Obesity and Joint Replacement, Part 2: Does Losing Weight First Improve Outcomes?

We have been discussing obesity and joint replacement operations, specifically knee replacements and hip replacements, and the common practice of denying these to people of size.

In Part One, we discussed the highly questionable ethics behind denying "obese" people joint replacement operations or requiring that they undergo weight loss counseling or bariatric surgery first. These practices keep many people of size from accessing joint replacements and improving their functional abilities and pain levels, sentencing many larger people to the difficulties of dealing with mobility challenges and a poorer quality of life.

Today, we discuss the data on whether losing weight before joint replacement actually improves long-term outcome, as so many doctors insist it will. Up till now it has been assumed that it will, but a closer look at longer-term research calls this assumption into question. Indeed, several recent studies that suggest that losing weight before knee replacement surgery does NOT improve outcome and might even result in worse outcomes.

Does Weight Loss Before Knee Replacement Help?

Of course, some readers will be asking, why not consider weight loss? If it will reduce the physical load on the joint and lessen pain and wear, why not pursue weight loss?

The answer is complicated.

It certainly seems logical that it would be advantageous to lose weight before an operation to replace a weight-bearing joint. There would be less weight and therefore less force on the joint, right?

And to be fair, there's definitely research that shows modest improvements in functionality, joint force load, and pain levels with weight loss in patients with knee pain.

However, like most weight-loss research, these studies usually follow patients only short-term so the usual weight rebound effect is conveniently overlooked or minimized.

Even studies that promote weight loss for knee osteoarthritis admit (my emphasis):

Whether substantial weight loss can delay or even reverse the symptoms associated with osteoarthritis remains to be seen.

In other words, they do NOT have long-term proof that weight loss improves outcomes; they just assume it does because short-term studies (often just a few months) suggest some improvement.

This is the problem with nearly all weight-loss research; it only follows the patients long enough to show some benefits of a quick loss, but rarely follow patients long-term because many of the benefits are lost and most of the weight is regained (and often more), and doctors don't want to acknowledge that.

Even the usual recommendation to "lose just 5-10%" of a person's weight is problematic. While some research indicates modest benefits, research is actually quite limited on the long-term effects of such a loss. And most dieters do not manage or just barely manage that 5-10% weight loss over time.

Reviews of long-term research shows that for most people, few maintain the weight loss over time, most of the weight loss is regained with time, and many people rebound to higher weights or greater abdominal fat than they began with. There are biological reasons for this weight regain; it's not just about willpower.

Furthermore, weight loss can present risks as well as benefits, frequent weight fluctuation can be detrimental to health, and intentional weight loss/"dietary restraint" is one of the strongest predictors of long-term weight gain.

As a result, some care providers are now recommending that obese patients strive for weight stability rather than weight loss, and that the emphasis be placed on improving health habits and health measures instead of reducing a number on a scale.

Unfortunately, because short-term research shows modest improvements in joint function with weight loss, doctors have extrapolated this to assume that significant weight loss will improve long-term outcomes for joint replacement surgeries. As a result, some deny joint replacement to people above a certain BMI, practically mandate attendance at weight loss programs first, browbeat their patients about weight loss, or strongly push for bariatric surgery instead.

But does weight loss before joint replacement improve outcomes?

Weight Loss Before Joint Replacement 

In two recent new studies, the common assumption that having patients lose weight before having knee replacement surgery will automatically improve outcomes is questioned.

In a California study, only 12.4% of more than 10,000 knee replacement patients studied and 18% of more than 4000 hip replacement patients  managed to lose at least 5% of their starting weight in the year before their surgery. Around 75% of both groups stayed stable. Those who did manage to lose weight before knee replacement surgery did no better than those who did not lose weight before surgery. They had similar rates of surgical site infections and re-admissions for complications.

This certainly calls into question how helpful weight loss supposedly is before knee replacement.

In a companion study, those who lost weight before joint replacement surgery and managed to keep it off afterwards actually did worse than those whose weight stayed stable. The weight loss knee replacement group had more hospital re-admissions than those who did not lose weight. Furthermore, the hip replacement group who lost weight had more deep-site surgical infections. The authors noted:

These findings raise questions about the safety of weight management before total replacement of the hip and knee joints.

Why this increase in infections occurred is not clear. One theory is that when people are placed on a significantly low-calorie diet, nutrition can be impaired. It is difficult to get the proper amounts of all the nutrients when caloric intake is too low, and diets for these mobility-impaired people are often quite low-calorie because increasing exercise is difficult. As a result, some people with significant weight loss or chronic dieting histories develop nutrient deficiencies, and these may impair immune function. Research confirms that people with nutrient deficiencies have a greater risk for infections and other complications after joint surgery.

So while weight loss may reduce stress on the joint, nutrient deficiencies from this weight loss may affect immune function and ability to "bounce back" after surgery, negating any potential benefits of weight loss.

Furthermore, many people who lose substantial weight before joint replacements gain back that weight and more after the surgery. The end result of weight loss before joint replacement may be that the patient ends up weighing MORE later on, as one study found:

A patient with [hip replacement] had increased risk of important post-surgical weight gain of 12% (OR = 1.12, 95% CI, 1.08, 1.16) for every kilogram of pre-operative weight loss...Patients less than 60 years and who have lost a substantial amount of weight prior to surgery appear to be at particularly high risk of important post-surgical weight gain.

Ironically, requiring or strongly encouraging patients to lose a substantial amount of weight prior to joint replacement may backfire and ultimately add to the patient's weight, not lessen it. Yet most doctors continue to demand weight loss before joint replacement. Only now the emphasis is on weight loss via bariatric surgery instead.

Quote from Ragen Chastain, found here.

What About Bariatric Surgery First?

Because bariatric surgery is one of the only ways to lose weight in the long term (though it comes with many other complications and ususally involves some weight regain), many orthopedic surgeons are forming de-facto partnerships with bariatric surgeons.

As a result, many people of size are effectively blackmailed into weight loss surgery by BMI restrictions on joint replacements. 

One study from the Mayo Clinic states, "Morbidly obese individuals with severe degenerative joint disease who are considered unsuitable for arthroplasty because of excess weight should be considered for bariatric surgery."

Another surgeon reports that he accepts patients for knee replacements up to a BMI of 50, but after that he refers them for bariatric surgery first. (Because it makes SO much sense for someone too "at-risk" for one type of surgery to undergo a different type of surgery instead.)

Yet the common assumption that bariatric surgery should be promoted because it would surely improve outcomes in "morbidly obese" patients with significant osteoarthritis should also be questioned.

Some research does indicate improved outcomes in those who had bariatric surgery before joint replacement. And one recent study that looked only at short-term (90 days!) complications found lower rates of complications in those who had had bariatric surgery. Of course, the media was all over this study and it has been widely cited to justify requiring weight loss surgery.

However, other research does not support better outcomes with bariatric surgery, yet the press conveniently ignores that. In one study, complications were actually higher in the group with recent bariatric surgery (less than 2 years). The authors concluded:

Bariatric surgery prior to TJA [Total Joint Arthroplasty] may not provide dramatic improvements in post-operative TJA surgical outcomes. 

In another study from a major research hospital, researchers found an increased rate of joint replacements in bariatric patients who had experienced large or very rapid weight loss. They noted, "These results contradict the tenant that weight loss is universally protective against arthritis and merit larger prospective investigations."

Another recent study did not find improved outcomes in those who had had bariatric surgery before joint replacement. Indeed, many had worse outcomes instead, needing more revision surgeries afterwards.

This was echoed in a recent large retrospective cohort study that found worse outcomes in the group that had bariatric surgery first, compared to high-BMI people who did not. The WLS group had more infection, pneumonia, blood clots, heart issues, revisions, and manipulations of the prosthetetic.

A recent meta-analysis found no significant benefit from bariatric surgery before joint replacement. The authors concluded:

For most peri-operative outcomes, bariatric surgery prior to THA or TKA does not significantly reduce the complication rates or improve the clinical outcome. This study questions the previous belief that bariatric surgery prior to arthroplasty may improve the clinical outcomes for patients who are obese or morbidly obese.

It may be that the potential benefits of reducing the load on the joint via weight loss from bariatric surgery may be outweighed by the nutrient deficits that are so common after weight loss surgery, even non-restrictive procedures. It may also be that the stresses on the body from rapid weight loss cause long-term damage to the body's ability to repair itself.

While some bariatric surgery patients have good outcomes and health improvement from the WLS, others have terrible outcomes, with significant nutritional deficits (sometimes despite supplements) and physical health problems. Some even die from the surgery or its after-effects. The problem is that you don't know which outcome group you are going to be in until after you've had the surgery. To strongly pressure joint replacement patients into bariatric surgery first means doctors are engaging in a high-stakes gamble with their patients' lives and quality of life.

And if joint replacement surgery at larger sizes is "too dangerous," why isn't weight loss surgery at larger sizes also too risky? Funny how patients are too fat for one surgery but surgeons can't wait to usher them into the Operating Room for WLS.

There are good reasons to question the common recommendation to have bariatric surgery before joint replacement. WLS is dangerous in and of itself, it often results in significant long-term nutrient deficits and other health problems, and it may not improve long-term outcomes for joint replacement.

However, as always, every person gets to make their own health decisions. Some people choose to have bariatric surgery before joint replacement and they have the right to do that. Others choose not to, and they also should have the right to do that. It's a choice with many pros and cons but one that should not be forced upon someone, which many doctors are essentially doing by denying joint replacement without bariatric surgery first.

In the past, care providers rarely studied whether or not bariatric surgery actually improved outcomes; they just assumed it will because it seems logical. But recent research shows there is good reason to question whether bariatric surgery really improves long-term outcome after all.

Mitigating Risk Through Better Management

Critics will no doubt point out that the risk for blood clots and post-operative infection are higher in obese patients and this is why they are concerned about operating on this group. This is true, and obese patients should be counseled about this fact. For example, one study found 6.7x the risk for infection in obese knee replacement patients, and 4.2x the risk for infection in obese hip replacement patients. The risk for infection is particularly strong among diabetics with a BMI over 40.

However, remember the dangers of using relative risk to discuss risk/benefit ratios; it can distort one's perception of risk. It is more helpful to use absolute numerical values so the magnitude of risks patients are assuming is more clear. One very large British study found that for knee replacements, risk for blood clots was increased from 2.0% to 3.3% and risk for infection from 3.0% to 4.1%, in obese patients with total knee replacements. For hip replacements, the risk for blood clots was increased from 2.2% to 3.3% and the risk for infection from 1.6% to 3.5% in obese patients. The authors noted (my emphasis):

Whilst an increased risk of wound infection and DVT/PE was observed amongst obese patients, absolute risks remain low and no such association was observed for MI, stroke and mortality.

However, the most important thing to point out is that an increased infection and clotting risk may be at least partly due to mismanagement of obese patients. Re-examining and changing the management protocols of these patients may improve outcomes independent of weight loss. 

For example, research shows that obese patients are chronically under-dosed with many medications. This is particularly relevant in antibiotics for preventing and treating infections, and in thromboprophylaxis medications for preventing blood clots after surgery. In other words, the two biggest risks of surgery in high-BMI patients may actually be largely preventable.

Obese patients, especially "morbidly-obese" (BMI 40+) and "super-obese" (BMI 50+) patients, are at particular risk for infections and may require larger initial antibiotic doses, extended or more frequent dosing regimens, use of more than one type of antibiotic, and perhaps topical infusions of antibiotics during surgery. This may help reduce their increased risk for infection after joint replacement surgery.

One recent study on infection in obese joint replacement patients strongly raised this issue of antibiotic underdosing. The authors found that above 100 kg (~220 lbs.), the rate of infections rose strongly. They noted that most patients in the study, regardless of BMI, were treated with a uniform dose (1.5g) of pre-op antibiotics and speculated that an increased antibiotic dose would help lower the rate of infections in this group. They stated:

The link between obesity and infection may be explained by several factors, but under-dosing of antibiotics is probably the most important to consider.

They also noted that noted that research examining the question of proper antibiotic dosage for obese patients undergoing joint replacement surgery was lacking. The problem of underdosing antibiotics in obese patients has been acknowledged in obstetric and bariatric surgery for several years. Why is it only NOW being brought up in orthopedic surgery?

Underdosing issues go beyond antibiotics. Research suggests that many obese patients are under-dosed with anti-clotting agents like heparin. One study found that weight-adjusted dosing cut the rate of blood clots in obese patients after surgery from 2.0% to 0.54% without increasing the risk for bleeding. Another study found that an extended prophylaxis period of anti-clotting agents lowered the risk for clots significantly, also without increasing bleeding.

Other surgical management protocols for obese patient need review as well. Some research suggests that surgical drains, often placed prophylactically in obese patients, have no benefit or may actually do more harm than good. Although further research is needed, one research review suggested omitting routine surgical drains in obese patients during joint replacement surgery.

As noted previously, another very interesting set of recent studies suggests that "morbid obesity" is less important that serum albumin levels on major complications like mortality and infections in joint replacement surgery. Serum albumin levels are an indicator of liver and kidney function but can also indicate nutrition status; obese people may be more at risk for malnutrition because of chronic dieting, highly restrictive intakes, or malabsorptive procedures like gastric bypass. Improving joint replacement outcomes might need to focus on measuring and fixing albumin levels and other nutrient deficits before surgery.

Bottom line, if the real concern is preventing poor outcomes, then perhaps the best approach is not to deny all high-BMI patients access to this surgery, but rather to lower morbidity by improving care for them instead via:

• Utilizing weight-based dosing more uniformly in antibiotics and blood clot prevention drugs 
• Using extended, adjunctive or more frequent antibiotic dosing regimens 
• Avoiding routine prophylactic surgical drains 
• Screening for and optimizing albumin and other nutrient levels before surgery

Ironically, a lot of the research on improving surgical outcomes in very obese patients is only done with bariatric surgery. It is past time to improve outcomes in high-BMI people in other types of surgery as well, including joint replacement surgery, instead of having to just extrapolate from bariatric surgery studies.

We need to know through evidence-based trials what the best protocols are for obese people undergoing joint replacement surgery. And in order to do that, we need for people of size to actually be given access to this surgery.

Summary

Sadly, even today, many orthopedic surgeons refuse to do knee replacements or hip replacements on anyone with a BMI over 35 or over 40 (or sometimes less).  In many places in the U.K., for example, people with a BMI over 35 have been routinely denied joint replacements and other surgeries. Some even deny joint replacements to those with a BMI over 30.

They do this because surgery is more technically challenging in very heavy people and because they view obesity as a voluntary condition brought on by poor lifestyle choices. They feel that losing weight is mostly a matter of willpower and choices, despite plenty of evidence to the contrary, and they feel they are doing their patients a favor by making them lose weight.

Surgeons also justify BMI restrictions by pointing out the short-term risks associated with orthopedic surgery in high-BMI people. They suggest that higher complication rates and somewhat lower functional outcomes justify denying surgery to this group and/or requiring weight loss or even bariatric surgery before joint replacement.

However, other surgeons are questioning the ethics of denying joint replacement surgery to high-BMI patients. They note that even very fat patients usually have good long-term outcomes from the surgery.

They recognize that the tremendous improvement in mobility, quality of life, knee function, and pain relief is worth the trade-off of a potentially increased risk for mild short-term morbidity. Many are willing to proceed with joint replacement surgery in high-BMI patients as long as they have been given informed consent about the benefits and risks.

It is reasonable to counsel obese patients about the potential risks of a higher weight before surgery, especially if they have co-morbidities like diabetes. However, the counseling should cover both risks and benefits. It should acknowledge that the magnitude of risk is relatively modest in most obese patients and that most have very good long-term results from both knee replacement surgery and hip replacement surgery.

Patients can also be counseled about the potential benefits of weight loss before joint replacement surgery, as long as the data used is realistic and the potential risks of weight loss are also covered. But weight loss should not be required in order to access such surgery because research is contradictory on whether this is helpful. Short-term research shows some benefits, but longer-term research shows little benefit and sometimes even harm. Furthermore, the risks of weight loss, yo-yo dieting, and bariatric surgery should not be overlooked. More research is needed, but requiring weight loss before surgery is certainly not evidence-based. The truth is that the evidence is mixed and the choice should be left to the patient.

Joint replacement surgery in very obese patients is technically harder and does carry risks. However, the magnitude of this risk is modest and the potential for improvement in quality of life is very strong. Restricting high-BMI people from joint replacement surgery or requiring them to lose weight in order to access this surgery is NOT justified or ethical.

Rather, the risks are a call to surgeons to further examine the long-overlooked issue of how they manage obese patients. Risks can most likely be mitigated by proper medication dosing and more optimal surgical management of high-BMI patients.

Instead of restricting joint replacement or requiring weight loss in high BMI patients, orthopedic surgeons should be focusing on how they can improve outcomes in this group through modifications to surgical management protocols.


References

General Information about Joint Replacement

• http://orthoinfo.aaos.org/topic.cfm?topic=a00389 - knee replacement info
• http://orthoinfo.aaos.org/topic.cfm?topic=a00377 - hip replacement info

Weight Loss Before Joint Replacement

Bone Joint J. 2014 May;96-B(5):629-35. doi: 10.1302/0301-620X.96B5.33136. The risk of surgical site infection and re-admission in obese patients undergoing total joint replacement who lose weight before surgery and keep it off post-operatively. Inacio MC, Kritz-Silverstein D, Raman R, Macera CA, Nichols JF, Shaffer RA, Fithian DC. PMID: 24788497

This study evaluated whether obese patients who lost weight before their total joint replacement and kept it off post-operatively were at lower risk of surgical site infection (SSI) and re-admission compared with those who remained the same weight. We reviewed 444 patients who underwent a total hip replacement and 937 with a total knee replacement who lost weight pre-operatively and sustained their weight loss after surgery. After adjustments, patients who lost weight before a total hip replacement and kept it off post-operatively had a 3.77 (95% confidence interval (CI) 1.59 to 8.95) greater likelihood of deep SSIs and those who lost weight before a total knee replacement had a 1.63 (95% CI 1.16 to 2.28) greater likelihood of re-admission compared with the reference group. These findings raise questions about the safety of weight management before total replacement of the hip and knee joints.

J Arthroplasty. 2014 Mar;29(3):458-64.e1. doi: 10.1016/j.arth.2013.07.030. Epub 2013 Sep 7. The impact of pre-operative weight loss on incidence of surgical site infection and readmission rates after total joint arthroplasty. Inacio MC, Kritz-Silverstein D, Raman R, Macera CA, Nichols JF, Shaffer RA, Fithian DC. PMID: 24018161

This study characterized a cohort of obese total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients (1/1/2008-12/31/2010) and evaluated whether a clinically significant amount of pre-operative weight loss (5% decrease in body weight) is associated with a decreased risk of surgical site infections (SSI) and readmissions post-surgery. 10,718 TKAs and 4066 THAs were identified. During the one year pre-TKA 7.6% of patients gained weight, 12.4% lost weight, and 79.9% remained the same. In the one year pre-THA, 6.3% of patients gained weight, 18.0% lost weight, and 75.7% remained the same. In TKAs and THAs, after adjusting for covariates, the risk of SSI and readmission was not significantly different in the patients who gained or lost weight pre-operatively compared to those who remained the same.

Osteoarthritis Cartilage. 2013 Jan;21(1):35-43. doi: 10.1016/j.joca.2012.09.010. Epub 2012 Oct 6.
Clinically important body weight gain following total hip arthroplasty: a cohort study with 5-year follow-up. Riddle DL, Singh JA, Harmsen WS, Schleck CD, Lewallen DG. PMID: 23047011

...DESIGN: We used multi-variable logistic regression to compare data from one of the largest US-based THA registries to a population-based control sample from the same geographic region. We also identified factors that increased risk of clinically important weight gain specifically among persons undergoing THA. The outcome measure of interest was weight gain of ≥5% of body weight up to 5 years following surgery. RESULTS: ...A patient with THA had increased risk of important post-surgical weight gain of 12% (OR = 1.12, 95% CI, 1.08, 1.16) for every kilogram of pre-operative weight loss. CONCLUSIONS: While findings should be interpreted with caution because of missing follow-up weight data, patients with THA appear to be at increased risk of clinically important weight gain following surgery as compared to peers. Patients less than 60 years and who have lost a substantial amount of weight prior to surgery appear to be at particularly high risk of important post-surgical weight gain. 

Arthritis Care Res (Hoboken). 2013 May;65(5):669-77. doi: 10.1002/acr.21880. Clinically important body weight gain following knee arthroplasty: a five-year comparative cohort study. Riddle DL, Singh JA, Harmsen WS, Schleck CD, Lewallen DG. PMID: 23203539

...METHODS: We used one of the largest US-based knee arthroplasty registries and a population-based control sample from the same geographic region to determine whether knee arthroplasty increases the risk of clinically important weight gain of ≥5% of baseline body weight over a 5-year postoperative period. RESULTS: Of the persons in the knee arthroplasty sample, 30.0% gained ≥5% of baseline body weight 5 years following surgery as compared to 19.7% of the control sample. The multivariable-adjusted (age, sex, body mass index, education, comorbidity, and presurgical weight change) odds ratio (OR) was 1.6 (95% confidence interval [95% CI] 1.2-2.2) in persons with knee arthroplasty as compared to the control sample. Additional arthroplasty procedures during followup further increased the risk for weight gain (OR 2.1, 95% CI 1.4-3.1) relative to the control sample. Specifically, among patients with knee arthroplasty, younger patients and those who lost greater amounts of weight in the 5-year preoperative period were at greater risk for clinically important weight gain. CONCLUSION: Patients who undergo knee arthroplasty are at an increased risk of clinically important weight gain following surgery. The findings potentially have broad implications to multiple members of the health care team. Future research should develop weight loss/maintenance interventions particularly for younger patients who have lost a substantial amount of weight prior to surgery, as they are most at risk for substantial postsurgical weight gain.

Bariatric Surgery Before Joint Replacement 

Bone Joint J. 2015 Nov;97-B(11):1501-5. doi: 10.1302/0301-620X.97B11.36477. Bariatric surgery does not improve outcomes in patients undergoing primary total knee arthroplasty. Martin JR, Watts CD, Taunton MJ. PMID: 26530652

Bariatric surgery has been advocated as a means of reducing body mass index (BMI) and the risks associated with total knee arthroplasty (TKA). However, this has not been proved clinically. In order to determine the impact of bariatric surgery on the outcome of TKA, we identified a cohort of 91 TKAs that were performed in patients who had undergone bariatric surgery (bariatric cohort). These were matched with two separate cohorts of patients who had not undergone bariatric surgery. One was matched 1:1 with those with a higher pre-bariatric BMI (high BMI group), and the other was matched 1:2 based on those with a lower pre-TKA BMI (low BMI group). In the bariatric group, the mean BMI before bariatric surgery was 51.1 kg/m(2) (37 to 72), which improved to 37.3 kg/m(2) (24 to 59) at the time of TKA. Patients in the bariatric group had a higher risk of, and worse survival free of re-operation (hazard ratio (HR) 2.6; 95% confidence interval (CI) 1.2 to 6.2; p = 0.02) compared with the high BMI group. Furthermore, the bariatric group had a higher risk of, and worse survival free of re-operation (HR 2.4; 95% CI 1.2 to 3.3; p = 0.2) and revision (HR 2.2; 95% CI 1.1 to 6.5; p = 0.04) compared with the low BMI group. While bariatric surgery reduced the BMI in our patients, more analysis is needed before recommending bariatric surgery before TKA in obese patients.

J Arthroplasty. 2016 Sep;31(9 Suppl):207-11. doi: 10.1016/j.arth.2016.02.075. Epub 2016 Mar 15. Lingering Risk: Bariatric Surgery Before Total Knee Arthroplasty. Nickel BT, Klement MR, Penrose CT, Green CL, Seyler TM, Bolognesi MP. PMID: 27179771

...METHODS: A total of 39,014 patients were identified in a claim-based review of the entire Medicare database with International Classification of Diseases, Ninth Revision codes to identify patients in 3 groups. Patients who underwent BS before total knee arthroplasty (group I: 5914 experimental group) and 2 control groups that did not undergo BS but had either a body mass index >40 (group II: 6480 bariatric control) or <25 (group III: 26,616 normal weight control)...RESULTS: ...Medical and surgical complication incidences were greatest in group I including: 4.98% deep vein thrombosis; 5.31% pneumonia; 10.09% heart failure; and 2-year infection, revision, and manipulation rates of 5.8%, 7.38%, and 3.13%, respectively. These values were significant elevation compared to III and slightly greater than II. CONCLUSIONS: This study demonstrates that BS before total knee arthroplasty is associated with greater risk compared to both nonobese and obese patients. This is possibly due to a higher incidence of medical or psychiatric comorbidities determined in the Medicare BS patients, wound healing difficulties secondary to gastrointestinal malabsorption, malnourishment from prolonged catabolic state, rapid weight loss before surgery, and/or age.

Bone Joint J. 2016 Sep;98-B(9):1160-6. doi: 10.1302/0301-620X.98B9.38024. Does bariatric surgery prior to total hip or knee arthroplasty reduce post-operative complications and improve clinical outcomes for obese patients? Systematic review and meta-analysis. Smith TO, Aboelmagd T, Hing CB, MacGregor A. PMID: 27587514

AIMS: Our aim was to determine whether, based on the current literature, bariatric surgery prior to total hip (THA) or total knee arthroplasty (TKA) reduces the complication rates and improves the outcome following arthroplasty in obese patients. METHODS: A systematic literature search was undertaken of published and unpublished databases on the 5 November 2015...RESULTS: From 156 potential studies, five were considered to be eligible for inclusion in the study. A total of 23 348 patients (657 who had undergone bariatric surgery, 22 691 who had not) were analysed. The evidence-base was moderate in quality. There was no statistically significant difference in outcomes such as superficial wound infection (relative risk (RR) 1.88; 95% confidence interval (CI) 0.95 to 0.37), deep wound infection (RR 1.04; 95% CI 0.65 to 1.66), DVT (RR 0.57; 95% CI 0.13 to 2.44), PE (RR 0.51; 95% CI 0.03 to 8.26), revision surgery (RR 1.24; 95% CI 0.75 to 2.05) or mortality (RR 1.25; 95% CI 0.16 to 9.89) between the two groups. CONCLUSION: For most peri-operative outcomes, bariatric surgery prior to THA or TKA does not significantly reduce the complication rates or improve the clinical outcome. This study questions the previous belief that bariatric surgery prior to arthroplasty may improve the clinical outcomes for patients who are obese or morbidly obese. This finding is based on moderate quality evidence. 

Other Possible Factors

Clin Orthop Relat Res. 2015 Oct;473(10):3163-72. doi: 10.1007/s11999-015-4333-7. Epub 2015 May 21. Low Albumin Levels, More Than Morbid Obesity, Are Associated With Complications After TKA. Nelson CL1, Elkassabany NM, Kamath AF, Liu J. PMID: 25995174

BACKGROUND: Morbid obesity and malnutrition are thought to be associated with more frequent perioperative complications after TKA. However, morbid obesity and malnutrition often are co-occurring conditions. Therefore it is important to understand whether morbid obesity, malnutrition, or both are independently associated with more frequent perioperative complications...METHODS: The National Surgical Quality Improvement Program (NSQIP) database was analyzed from 2006 to 2013. Patients were grouped as morbidly obese (BMI ≥ 40 kg/m(2)) or nonmorbidly obese (BMI ≥ 18.5 kg/m(2) to < 40 kg/m(2)), or by low serum albumin (serum albumin level < 3.5 mg/dL) or normal serum albumin (serum albumin level ≥ 3.5 mg/dL)...RESULTS: Mortality was not increased in the morbidly obese group (0.14% vs 0.14%; p = 0.942)...The group with low serum albumin had higher mortality than the group with normal serum albumin (0.64% vs 0.15%; OR, 3.17; 95% CI, 1.58-6.35; p =0.001)... CONCLUSIONS: Morbid obesity is not independently associated with the majority of perioperative complications measured by the NSQIP and was associated only with increases in progressive renal insufficiency, superficial surgical site infection, and sepsis among the 21 perioperative variables measured. However, low serum albumin was associated with increased mortality and multiple additional major perioperative complications after TKA. Low serum albumin, more so than morbid obesity, is associated with major perioperative complications. This is an important finding, as low serum albumin may be more modifiable than morbid obesity in patients who are immobile or have advanced knee osteoarthritis.

HSS J. 2017 Feb;13(1):66-74. doi: 10.1007/s11420-016-9518-4. Epub 2016 Aug 16. Hypoalbuminemia Is a Better Predictor than Obesity of Complications After Total Knee Arthroplasty: a Propensity Score-Adjusted Observational Analysis. Fu MC, McLawhorn AS, Padgett DE, Cross MB. PMID: 2816787

...METHODS: TKA cases were identified from the National Surgical Quality Improvement Program from 2005 to 2013... Malnutrition was defined as hypoalbuminemia (<3.5 g/dL). Patients were classified by BMI as follows: non-obese (18.5-29.9), obese I (30-34.9), obese II (35-39.9), or obese III (≥40). Postoperative complications were compared across obesity and nutritional statuses. Multivariable propensity-adjusted logistic regressions were performed to determine associations between malnutrition, obesity, and 30-day outcomes. RESULTS: There were 71,599 cases identified, with 34,800 (48.6%) having albumin measurements...Malnutrition prevalence increased with BMI (6.1% in obese III vs. 3.7% in non-obese). With propensity-adjusted multivariable analysis, obese III was the only obesity class associated with any complication, wound complication, and reoperation. Hypoalbuminemia was a stronger and more consistent independent risk factor, for any complication, wound, cardiac, or respiratory complications, and death. CONCLUSIONS: Hypoalbuminemia is a more consistent independent predictor of complications after TKA than obesity. Strategies for medical optimization of these conditions should be investigated.

Antibiotic Dosing and Surgical Infections

Acta Orthop. 2016;87(2):132-8. doi: 10.3109/17453674.2015.1126157. Epub 2016 Jan 5. Body mass and weight thresholds for increased prosthetic joint infection rates after primary total joint arthroplasty. Lübbeke A1, Zingg M1, Vu D2, Miozzari HH1, Christofilopoulos P1, Uçkay I1,2, Harbarth S3, Hoffmeyer P1. PMID: 26731633

...We included all 9,061 primary hip and knee arthroplasties (mean age 70 years, 61% women) performed between March 1996 and December 2013 where the patient had received intravenous cefuroxime (1.5 g) perioperatively. The main exposures of interest were BMI (5 categories: < 24.9, 25-29.9, 30-34.9, 35-39.9, and ≥ 40) and weight (5 categories: < 60, 60-79, 80-99, 100-119, and ≥ 120 kg). Numbers of TJAs according to BMI categories (lowest to highest) were as follows: 2,956, 3,350, 1,908, 633, and 214, respectively. The main outcome was prosthetic joint infection. The mean follow-up time was 6.5 years (0.5-18 years). RESULTS: 111 prosthetic joint infections were observed: 68 postoperative, 16 hematogenous, and 27 of undetermined cause. Incidence rates were similar in the first 3 BMI categories (< 35), but they were twice as high with BMI 35-39.9 (adjusted HR = 2.1, 95% CI: 1.1-4.3) and 4 times higher with BMI ≥ 40 (adjusted HR = 4.2, 95% CI: 1.8-9.7). Weight ≥ 100 kg was identified as threshold for a significant increase in infection from the early postoperative period onward (adjusted HR = 2.1, 95% CI: 1.3-3.6). INTERPRETATION: BMI ≥ 35 or weight ≥ 100 kg may serve as a cutoff for higher perioperative dosage of antibiotics.

Media Articles on Joint Replacement Restrictions on BMI

• http://www.hss.edu/newsroom_knee-replacements-morbidly-obese-individuals.asp#.U-rVcvldW4g - "Study Overturns Common Assumption About Knee Replacements in Morbidly Obese Individuals"
• http://www.drsharma.ca/bmi-does-not-affect-outcomes-in-knee-replacement-surgery.html - "BMI Does Not Affect Outcomes in Knee Replacement Surgery"
• http://bonesmart.org/forum/threads/bmi-calculator-what-to-do-when-the-surgeon-says-youre-too-heavy-for-joint-replacement-surgery.15969/ - "What to Do When the Surgeon Says You're Too Heavy for Joint Replacement Surgery"
• http://health.usnews.com/health-news/patient-advice/articles/2016-04-11/too-fat-for-surgery - "Too Fat for Surgery" 
• http://www.erasmusmc.nl/erasmusjournalofmedicine/2787834/6th/EJM06_PAG_54-57 - "Sorry, but you will have to lose weight before receiving your knee replacement"
• https://www.peerwell.co/blog/2017/05/11/have-to-lose-weight-before-joint-replacement/ - "Told to Lose Weight Before a Joint Replacement Surgery? Here's Why" 

Obesity and Joint Replacement, Part 1: Are BMI Restrictions Ethical?

Should "obese" people be required to lose weight before being permitted to get joint replacement surgery? Or a kidney transplant? Or before receiving fertility treatment? Or to donate an organ?

The question of weight restrictions on access to healthcare is one of the most critical ethical questions in healthcare today. It is certainly one that causes great difficulties for many people of size as they seek the best medical care and quality of life possible. As one doctor notes:

We talk about racial disparities in care and gender disparities in care, but there's actually weight disparities in care because these patients aren't getting needed therapy because of their weight.

Many people of size are denied access to Total Knee Arthroplasty (TKA, a.k.a. knee replacement) or Total Hip Arthroplasty (THA, a.k.a. hip replacement), based solely on Body Mass Index (BMI). They are similarly denied access to many other procedures as well, but let's focus on joint replacements today.

It will come as no surprise to readers that I oppose such restrictions, but let's take a moment to discuss fairly the arguments for and against BMI cut-offs and weight loss counseling for joint replacement surgery.

Obesity and Joints

One risk associated with obesity that is pretty consistent between studies is the negative effect of a higher weight on joints like knees and hips.

For most risks, an association between obesity and a particular condition (diabetes, for example) is a correlation, not causation. Many type 2 diabetics are obese, for example, but fatness does not cause diabetes, or all fat people would be diabetic (they aren't), and no skinny person would have type 2 diabetes (many do). It may well be instead that fatness is merely a symptom of an underlying condition (like the insulin resistance of PCOS) and that condition predisposes towards diabetes, rather than fatness is an actual cause of diabetes.

But for joint issues, there is more evidence for a causal relationship. Extra weight creates extra stress on the joints, and the knees are especially vulnerable. As a result, fat people do get more arthritis, mostly in the knees but perhaps also in the hips, and this can create significant pain and mobility issues for some.

However, there may be more to the story, because fat people get more hand arthritis too, and that is not a weight-bearing joint. Some have speculated that there may be metabolic and/or inflammatory factors predisposing to arthritis in heavier people. Lipedema, an adipose tissue disorder which affects many people of size, has also been shown to increase risk for knee arthritis, independent of weight.

Whatever the relationship is, at some point many people of size experience joint pain and struggle to figure out how to deal with that, which at some point might include surgically replacing the joint.

Alternatives to Joint Replacement 

Of course, it's important to remember that joint replacement is not the only option for treating arthritic joints. It's always important to explore the least-invasive options available before resorting to surgery. Many doctors will require patients to do several of the following therapies before considering joint replacement surgery because they may help the patient delay or completely avoid joint replacement surgery:

• Physical therapy to strengthen and balance the muscles around the knees
• Stretching exercises to increase flexibility and loosen tight muscles
• Pilates, water exercise, or directed exercise programs to increase strength and flexibility
• Injections of various types into the joint to help reduce inflammation and improve viscosity 

In addition to these traditional therapies, many patients have found help with:

• Acupuncture to reduce pain and loosen tight muscles
• Chiropractic care to keep the pelvis and back in better alignment and reduce joint stress
• Focused bodywork, like medical massage, fascial release, etc. to reduce pain, loosen tight muscles, and release scar tissue and restrictions
• Orthotics for better arch support and improved gait
• Muscle re-education programs (like the Alexander Technique or Rolfing) to address muscle strength imbalance and gait issues
• Various nutritional supplements (glucosamine, bone broth/gelatin, chondroitin, etc.) to help repair cartilage in the joint area and reduce pain

Stories of people of size using these and other ideas can be found here and here.

However, despite all these measures, some people of size have to consider at some point whether or not to get a joint replaced.

Of course, surgery in larger people is more technically difficult and always carries more risk for anesthesia accidents and surgical site infections, so surgeons aren't wild about doing surgery on fat people. That is understandable.

But should these challenges mean they should completely DENY access to knee or hip replacement surgery to fat people? Is it ethical to deny patients access to medical procedures because of weight restrictions? Is it ethical to require obese patients to undergo weight loss treatment before they can even be considered for joint replacements?

These are the critical ethics questions faced by orthopedic care providers these days.

Ethics Questions

One orthopedic surgeon, interviewed for an article about the ethics of denying high-BMI people access to knee replacement surgery, stated:

Obesity often causes osteoarthritis of the knee at relatively young age and these patients present themselves at your out-patient clinic demanding a total knee replacement as a solution for their problem...Bariatric surgery can definitely be an important part of treatment, but only in a multidisciplinary context in which psychological treatment is also applied. 'Obesity is a disorder which will only pass after specific treatment by a whole team of specialists. On top of that, if the obesity remains, the other non-orthopaedic health risks stay as well...for multiple reasons, a TKR [total knee replacement] is not the appropriate solution for a morbidly obese patient and will not lead to weight reduction. It is important to address the root cause and not fight the symptoms. Morbid obesity should be seen as a life-event that requires a multidisciplinary approach and cannot be resolved just by an orthopaedic surgeon.

This shows this doctor's bias. Nothing else matters but weight loss and "resolving" obesity. He views obese patients as having psychological problems, so he believes they need treatment by a "whole team of specialists." He sees fat people as physically and psychologically sick, thinks they brought the problem on themselves, and doesn't believe they deserve a joint replacement unless they earn it by being "reforming" their lives. Since a knee replacement doesn't usually produce weight loss (and to him weight loss is the real goal), he sees no reason to do a joint replacement on obese people unless they agree to weight loss treatment first, and joint replacement is the blackmail he holds over patients' heads until they comply.

News flash! The main justification for doing joint replacements is not to solve an "obesity problem."

Yes, many studies about weight patterns after joint replacement show that joint replacement doesn't usually result in weight loss and is not justified as a way to help people lose weight. However, these studies miss the point.

Whether or not weight loss occurs after joint replacement is IRRELEVANT. Impaired mobility and major pain are a significant interference with quality of life. The purpose of joint replacements is to IMPROVE QUALITY OF LIFE.

Let's say that again. Weight loss should NOT be the goal of joint replacement for obese people. Instead, the main goal is to improve quality of life, reduce pain, and to regain function. 

That this question is even brought up reveals the bias in so much of health care. The focus is on weight loss and little else. If a procedure does not lead to weight loss, then its utility and appropriateness is questioned, even when it brings many improvements in function and pain. And if people of size decline weight loss treatment, then many health care providers believe we don't "deserve" access to the same level of health care as everyone else.

Shame and Blame Only for Fat People

Another ethical problem in joint replacement discussions is the issue of blame. Fat people are not seen as "deserving" a joint replacement because they are blamed for developing the joint issues in the first place. The article quoted above has a typical viewpoint:

A patient needs to take responsibility for the choices they make. By choosing for an unhealthy lifestyle, consuming junk food frequently and rarely exercising, your tendency to become overweight is greater than that of a healthy individual. The greater the load a joint has to carry, the sooner it wears out and the sooner a total knee replacement is required. 

Here is the typical assumption of most care providers, that obesity is a choice. In other words, fat people are only fat because they have bad habits and refuse to take responsibility for them.

Yet the issue of obesity is far more complicated, since many fat people do not have "bad" habits and yet still are fat. Genetics are highly relevant. In addition, many diseases (such as Polycystic Ovary Syndrome and Lipedema) and medications (such as steroids, birth control, or SSRIs) can result in weight gain and obesity. The bottom line is that what causes obesity is quite complex and that for many people, OBESITY IS NOT A BEHAVIOR.

Yet orthopedists routinely justify denying joint replacement surgery to fat people based on the idea that they have caused their own condition and don't "deserve" treatment.

Sadly, shame and blame are part of the joint replacement discussion only for fat people. Average-sized people are rarely held responsible for their own mobility challenges, even those who have caused or added to the issue by engaging in certain sports or by participating in extreme sports.

Few athletes are denied joint replacements or other surgeries even though their injuries may lead to joint issues at a relatively early age and a high rate of needing the artificial joint replaced. But fat people are felt to have caused their own disability and therefore are seen as not "deserving" treatment. Haven't devotees of extreme sports and over-exercising brought on their own joint issues? Yet they are rarely denied joint replacements.

Don't forget, fat people have accidents and injuries too. Weight can exacerbate an injury and speed the development of arthritis, yes, but is often not the original cause. As with thinner people, the original injury causes the problem; the weight may accelerate susceptibility to arthritis but does not cause it. Yet many fat people with a history of injury are denied access to joint replacements and told that they only developed arthritis because they were fat, completely ignoring the role of the intervening injury.

But does it really matter why the condition developed? Playing the blame game does not serve anyone. EVERYONE deserves to have maximum function, mobility, and relief of pain. In the end, it does not matter why the arthritis has developed, just that it has developed and that it needs to be treated.

Yet many high-BMI patients are often told that they must lose weight to a certain BMI, are referred for bariatric surgery, or must submit to hard-core weight loss counseling or medical weight loss programs (which is often condescending or which involve dubious very low calorie diets) in order to be considered for a joint replacement.

Ethically, physicians can present information about the possible benefits of weight loss and can offer assistance for those who wish to pursue weight loss. It is one form of treatment that can be considered, and some people will be interested in pursuing it.

However, informed consent means that patients need to be presented with information on the benefits AND the risks of a proposed treatment. Therefore, physicians should also have to be honest about the strong evidence that few people manage to lose to a reasonable BMI or keep the weight off for any meaningful length of time, that weight loss has its own risks, and that for many, weight loss often leads to weight cycling and greater rebound, and weight cycling also has risks.

People of size can be counseled about the potential benefits and risks of weight loss before joint replacement. But informed consent means that patients also have the right not to choose a particular therapy. To outright deny the surgery, or to blackmail people into weight loss counseling or risky bariatric surgery in order to have access to a procedure to regain a normal life is fraught with ethical problems. It is just plain WRONG.

Some doctors even deny access to pain relief medication unless fat patients show a certain amount of weight loss. The comments section of one blog post tells such a story:

Now the...doctor is telling a woman I know that she needs to lose large amounts of weight before he can sign her up for a pain management clinic. Yes, being unable to exercise for the past year due to serious knee issues has meant that she’s gained weight… but if she’s serious about getting pain-free, apparently she will miraculously become able to do heavy-duty exercise until she loses fifty pounds and is suddenly worthy to have her pain managed.

Sometimes fat patients are even denied medical treatments to lessen pain:

A colleague of mine told me today that he was denied a cortisone shot in his knee by the VA because of his weight. He was told that when he got down to 250 pounds, then he could have the shot. This seems so wrong to me. He wants to be more active, but cannot because of knee pain. This pain is treatable, and the treatment could enable him to be more active, which would improve his health. But, they will not treat his knee pain because of their pre-conceived notion of what is healthy.

This is another ethical lapse; pain relief should not be used as emotional and physical blackmail into weight loss compliance.

Inevitably, when weight loss fails, as research shows it almost certainly will, that leaves patients with no recourse for pain relief. As one care provider succinctly put it in an article about denying hip replacements to patients with a BMI over 30:

Relief of pain is a universal human right.

Denying fat people adequate pain relief simply because of their size is blatantly unethical. As another commentator in the article remarked, "The decision is perverse and appears to breach basic principles of healthcare."

What Happens When Joint Replacement Is Denied?

Another important ethics question ignored by many in the orthopedics field is what happens to obese people who are denied access to joint replacements?

One recent online article did look at this question (my emphasis):

Because of the increased risks of complications, it is common practice for some surgeons to restrict the use of TKA in patients with a BMI of 40 or higher. Based on the current available data, many surgeons and surgeon groups across the country withhold surgical intervention in morbidly obese patients until body weight is optimized and associated medical comorbidities are better controlled...The medical and societal implications of withholding TKA in morbidly obese patients are unknown. 

We posit three potential outcomes for patients who are denied TKA based on their having a BMI of 40 or higher and other associated comorbidities: 1) The patient chooses to seek a second opinion and have total joint arthroplasty performed at another institution. 2) The patient chooses to seek appropriate medical options such as medical weight management counseling, bariatric surgery, or both, and achieves successful weight reduction to meet the total joint arthroplasty healthy BMI threshold (BMI less than 40). 3) The patient chooses to seek appropriate medical options such as medical weight management counseling and/or bariatric surgery, but is unable to achieve successful weight reduction to meet the total joint arthroplasty healthy BMI threshold. 

We propose that this last group of patients is the cohort that is most concerning and may benefit most from a targeted care pathway and a multidisciplinary medical weight loss management team. This healthcare team should include an orthopedic surgeon, bariatric surgeon, registered dietitian, exercise specialist, and mental health provider who can in concert provide comprehensive support for the morbidly obese patient to safely achieve the target body weight and BMI required for a safe and effective TKA that can improve quality of life. We are in the initial stages of developing such a program at our institution.

It's great that this group of doctors are actually concerned about what happens to fat people who are denied joint replacement access. However, it's appalling that their answer is to simply pressure those people into ever more radical weight loss techniques (and apparently, bariatric surgery).

They refuse to relax their clinic's BMI restrictions on the premise that it is too risky for these patients to undergo surgery, yet it's perfectly fine for those same people to undergo bariatric surgery instead? Somehow they miss the irony in this protocol.

Furthermore, they COMPLETELY MISS what is the most likely outcome of denying fat people joint replacement ─ increasing disability and pain, accompanied by decreasing mobility and fitness.

These doctors assume that fat people denied surgery will either lose weight (despite low long-term success rates of even fairly small amounts of weight), undergo radical weight loss treatment (on the assumption that this will help improve outcomes), or go find another doctor who will do their surgery at their weight.

They are completely discounting the many, many fat people who will stop their search right there because they assume that all orthopedic surgeons will deny joint replacement to them. It also ignores the fact that many fat people live in areas where indeed, all orthopedic surgeons do deny joint replacement to fat people.

And in the meantime, the arthritis just gets worse (making it harder to operate on), and the person becomes increasingly disabled. As Dr. John Morton of Stanford University School of Medicine notes:

Not operating on obese patients to avoid risk or cost can backfire, Morton points out. "When you delay treatment of these patients, it gets worse," he says.

The result of denying joint surgery based on BMI is that many fat people will grow increasingly disabled, increasingly unfit, and increasingly immobile because they cannot access the procedures which could help them regain their mobility and decrease their pain.

Since fitness is the biggest key to wellness and longevity regardless of BMI, denying fat people joint replacement may well shorten their lives. 

This is why fat people often stop seeing doctors for years and years. The condescending and patronizing way they are treated, the unrelenting pressure for radical weight loss or bariatric surgery, the denial of access to pain relief or procedures to help improve quality of life...all this is why fat people have so little trust in doctors.

And it's typical that even well-meaning providers like the ones in this article simply do not have a clue how they actually often WORSEN fat people's health in their attempt to "help" them.

Summary

Sadly, even today, a lot of orthopedic surgeons still refuse to do knee replacements or hip replacements on anyone with a BMI over 35 or over 40 (or sometimes less). 

In many places in the U.K., for example, people with a BMI over 35 have been routinely denied joint replacements and other surgeries. Some even deny joint replacements to those with a BMI over 30.

They justify this by pointing out the short-term risks associated with orthopedic surgery in high-BMI people. They suggest that higher complication rates and somewhat lower functional outcomes justify denying surgery to this group.

However, while substantial research shows that obese patients have higher rates of short-term problems like infection, blood loss, surgical revisions, blood clots and slower recovery after joint replacement surgery, not all research shows increased risks.

Furthermore, obese patients often show greater overall improvements in function and pain relief than non-obese patients, or the differences are not clinically meaningful.

Although clearly obese patients should be counseled about the potential risks (particularly the risk for infection among diabetics with a BMI over 40), the magnitude of risk is relatively modest and not so great that it justifies precluding obese patients from this surgery.

Rather, the risks are a call to surgeons to further examine the long-overlooked issue of proper medication dosing, the use of surgical drains, and wound management in high-BMI patients. 

Although total function may be modestly less improved and more revisions may need to be done in larger patients, most obese patients have very good long-term results from the surgery, even when both knees are replaced.

Even in super-obese patients (BMI over 50), joint replacements last well, although total function may be somewhat impacted compared to average-sized people.

Similarly, despite some increase in short-term risks, obese people respond well to hip replacement surgery and do well in the long-term. One study which followed obese hip replacement patients for a mean of 14.5 years concluded:

Our findings suggest there is no evidence to support withholding total hip replacement from obese patients with arthritic hips on the grounds that their outcome will be less satisfactory than those who are not obese.

Furthermore, if overall health is the real priority, the advantages of joint replacement for obese people is obvious.

It's hard to work on fitness when exercising results in high levels of pain. Yet once the joint is replaced, mobility is greatly increased and pain levels are decreased. Whether or not joint replacement leads to weight loss post-operatively is irrelevant; better mobility and less pain is a significant gain in quality of life and may also lead to better fitness, independent of weight change.

And better fitness, regardless of BMI, improves health, life span, and often quality of life. As one study put it:

Performing TKA or THA on patients with high BMI may increase mobility leading to improved quality of life.

Bottom line, obese people should not be denied access to the potentially life-changing pain relief and functional improvement of joint replacement surgery.

Although some orthopedic surgeons still outright deny surgery or require that high-BMI people lose weight or undergo bariatric surgery before being considered candidates for a joint replacement, more surgeons are beginning to recognize that such restrictions are unethical and unfair. One study stated:

Withholding surgery based on the BMI is not justified. 

Another study's authors concluded:

Universal denial of surgery based on BMI is unwarranted.

Some surgeons do not withhold knee replacement surgery, but do require that patients be referred to weight loss specialists first before being able to access surgery, even if such referrals do not result in weight loss. One recent review states:

We believe that obese patients should be informed of the above-mentioned risks and should be advised to lose weight. Many patients will fail to achieve this goal without professional help, so we refer obese patients with osteoarthritis to a multidisciplinary obesity outpatient clinic. If this approach fails to result in weight loss, the patient at least benefits from a thorough analysis of existing comorbidity and optimization of his or her medical condition. We do not withhold a total knee arthroplasty from these patients, but we inform them extensively regarding the risk that their obesity poses with regard to this procedure.

This presents another ethical dilemma. It is of course reasonable to inform patients of their risk profile before surgery, and this includes the potential risks associated with obesity and surgery. However, is this "extensive" information about risk presented neutrally without judgment, or is it done with scare-mongering and emotional blackmail? Too many care providers err on the side of the latter instead of the former in hopes of scaring fat people into weight loss compliance. This is not ethical and is not good medicine.

Similarly, the potential benefits of weight loss can be presented as a therapeutic option ─ as long as the surgeon also gives full disclosure of the potential risks of weight loss/cycling and its poor long-term success rate. But rarely do doctors acknowledge both the pros and cons of weight loss, and many emotionally harass patients about losing weight or mandate weight loss treatment before surgery can be accessed.

Fortunately, there is some good news on this topic. In the last few years, more and more surgeons and organizations are speaking out against BMI restrictions on access to joint replacements. They recognize that the tremendous improvement in mobility, quality of life, knee function, and pain relief is worth the trade-off of a potentially increased risk for mild short-term morbidity. As one review put it:

The improvements in patient-reported outcome measures experienced by patients were similar, irrespective of body mass index. Health policy should be based on the overall improvements in function and general health gained through surgery. Obese patients should not be excluded from the benefit of total knee arthroplasty, given that their overall improvements were equivalent to those of patients with a lower body mass index.

Other care providers are not quite there yet but are at least beginning to recognize the ethical implications of such restrictions and are debating their merits, as in this article:

While obesity does raise the risks of surgical complications, those don't always outweigh the benefits of the procedure, says Dr. Michael Parks, an orthopedic surgeon at the Hospital for Special Surgery in New York City who chairs the American Academy of Orthopaedic Surgeons Workgroup on Obesity..."We have to weigh ... their improvement in quality of life versus the potential costs," he adds.

And some care providers are also now beginning to recognize that much short-term morbidity in obese people may be prevented with different medication dosing and re-evaluating standard surgical protocols.

IT'S ABOUT TIME.

Now it's time to ensure that those surgeons who are still resisting treating high-BMI people also get the memo.

*You can read more about one Health At Every Size activist's journey with knee replacements here. You can read more about doctors requiring weight loss surgery in order for high-BMI patients to access knee replacement here. 


References

Media Articles on Joint Replacement Restrictions on BMI

• http://www.hss.edu/newsroom_knee-replacements-morbidly-obese-individuals.asp#.U-rVcvldW4g - "Study Overturns Common Assumption About Knee Replacements in Morbidly Obese Individuals"
• http://www.drsharma.ca/bmi-does-not-affect-outcomes-in-knee-replacement-surgery.html - BMI Does Not Affect Outcomes in Knee Replacement Surgery
• http://bonesmart.org/forum/threads/bmi-calculator-what-to-do-when-the-surgeon-says-youre-too-heavy-for-joint-replacement-surgery.15969/ - What to Do When the Surgeon Says You're Too Heavy for Joint Replacement Surgery
• http://health.usnews.com/health-news/patient-advice/articles/2016-04-11/too-fat-for-surgery - "Too Fat for Surgery" 
• http://www.erasmusmc.nl/erasmusjournalofmedicine/2787834/6th/EJM06_PAG_54-57 - "Sorry, but you will have to lose weight before receiving your knee replacement"

BMI and Morbidity from Knee Replacement Surgery (positive and negative)

J Bone Joint Surg Br. 2006 Mar;88(3):335-40. Does obesity influence the clinical outcome at five years following total knee replacement for osteoarthritis? Amin AK1, Patton JT, Cook RE, Brenkel IJ. PMID: 16498007

A total of 370 consecutive primary total knee replacements performed for osteoarthritis were followed up prospectively at 6, 18, 36 and 60 months. The Knee Society score and complications (perioperative mortality, superficial and deep wound infection, deep-vein thrombosis and revision rate) were recorded...There was no statistically-significant difference in the complication rates for the subgroups studied. Obesity did not influence the clinical outcome five years after total knee replacement.

J Bone Joint Surg Am. 2012 Oct 17;94(20):1839-44. doi: 10.2106/JBJS.K.00820. The influence of obesity on the complication rate and outcome of total knee arthroplasty: a meta-analysis and systematic literature review. Kerkhoffs GM1, Servien E, Dunn W, Dahm D, Bramer JA, Haverkamp D. PMID: 23079875

...A search of the literature was performed, and studies comparing the outcome of total knee arthroplasty in different weight groups were included...twenty studies were included in the data analysis. The presence of any infection was reported in fourteen studies including 15,276 patients (I2, 26%). Overall, infection occurred more often in obese patients, with an odds ratio of 1.90 (95% confidence interval [CI], 1.46 to 2.47). Deep infection requiring surgical debridement was reported in nine studies including 5061 patients (I2, 0%). Deep infection occurred more often in obese patients, with an odds ratio of 2.38 (95% CI, 1.28 to 4.55). Revision of the total knee arthroplasty, defined as exchange or removal of the components for any reason, was documented in eleven studies including 12,101 patients (I2, 25%). Revision for any reason occurred more often in obese patients, with an odds ratio of 1.30 (95% CI, 1.02 to 1.67). CONCLUSIONS: Obesity had a negative influence on outcome after total knee arthroplasty.

Bone Joint J. 2016 Sep;98-B(9):1160-6. doi: 10.1302/0301-620X.98B9.38024. Does bariatric surgery prior to total hip or knee arthroplasty reduce post-operative complications and improve clinical outcomes for obese patients? Systematic review and meta-analysis. Smith TO, Aboelmagd T, Hing CB, MacGregor A. PMID: 27587514 

AIMS: Our aim was to determine whether, based on the current literature, bariatric surgery prior to total hip (THA) or total knee arthroplasty (TKA) reduces the complication rates and improves the outcome following arthroplasty in obese patients. METHODS: A systematic literature search was undertaken of published and unpublished databases on the 5 November 2015. All papers reporting studies comparing obese patients who had undergone bariatric surgery prior to arthroplasty, or not, were included. Each study was assessed using the Downs and Black appraisal tool. A meta-analysis of risk ratios (RR) and 95% confidence intervals (CI) was performed to determine the incidence of complications including wound infection, deep vein thrombosis (DVT), pulmonary embolism (PE), revision surgery and mortality. RESULTS: From 156 potential studies, five were considered to be eligible for inclusion in the study. A total of 23 348 patients (657 who had undergone bariatric surgery, 22 691 who had not) were analysed. The evidence-base was moderate in quality. There was no statistically significant difference in outcomes such as superficial wound infection (relative risk (RR) 1.88; 95% confidence interval (CI) 0.95 to 0.37), deep wound infection (RR 1.04; 95% CI 0.65 to 1.66), DVT (RR 0.57; 95% CI 0.13 to 2.44), PE (RR 0.51; 95% CI 0.03 to 8.26), revision surgery (RR 1.24; 95% CI 0.75 to 2.05) or mortality (RR 1.25; 95% CI 0.16 to 9.89) between the two groups. CONCLUSION: For most peri-operative outcomes, bariatric surgery prior to THA or TKA does not significantly reduce the complication rates or improve the clinical outcome. This study questions the previous belief that bariatric surgery prior to arthroplasty may improve the clinical outcomes for patients who are obese or morbidly obese. This finding is based on moderate quality evidence. 

Osteoarthritis Cartilage. 2014 Jul;22(7):918-27. doi: 10.1016/j.joca.2014.04.013. Epub 2014 May 13. The effect of body mass index on the risk of post-operative complications during the 6 months following total hip replacement or total knee replacement surgery. Wallace G, Judge A, Prieto-Alhambra D, de Vries F, Arden NK, Cooper C. PMID: 24836211

OBJECTIVE: To assess the effect of obesity on 6-month post-operative complications following total knee (TKR) or hip (THR) replacement. DESIGN: Data for patients undergoing first THR or TKR between 1995 and 2011 was taken from the Clinical Practice Research Datalink...RESULTS: 31,817 THR patients and 32,485 TKR patients were identified for inclusion. Increasing BMI was associated with a significantly higher risk of wound infections, from 1.6% to 3.5% in THR patients (adjusted P < 0.01), and from 3% to 4.1% (adjusted P < 0.05) in TKR patients. DVT/PE risk also increased with obesity from 2.2% to 3.3% (adjusted P < 0.01) in THR patients and from 2.0% to 3.3% (adjusted P < 0.01) in TKR patients. Obesity was not associated with increased risk of other complications. CONCLUSION: Whilst an increased risk of wound infection and DVT/PE was observed amongst obese patients, absolute risks remain low and no such association was observed for MI, stroke and mortality. However this is a selected cohort (eligible for surgery according to judgement of NHS GPs and surgeons) and as such these results do not advocate surgery be given without consideration of BMI, but indicate that universal denial of surgery based on BMI is unwarranted.

J Surg Res. 2012 May 1;174(1):7-11. doi: 10.1016/j.jss.2011.05.057. Epub 2011 Jun 25. Does BMI affect perioperative complications following total knee and hip arthroplasty? Suleiman LI1, Ortega G, Ong'uti SK, Gonzalez DO, Tran DD, Onyike A, Turner PL, Fullum TM. PMID: 21816426

BACKGROUND: Orthopedic surgeons are reluctant to perform total knee (TKA) or hip (THA) arthroplasty on patients with high body mass index (BMI). Recent studies are conflicting regarding the risk of obesity on perioperative complications. Our study investigates the effect of BMI on perioperative complications in patients undergoing TKA and THA using a national risk-adjusted database. METHODS: A retrospective analysis was performed using the 2005-2007 American College of Surgeons-National Surgical Quality Improvement Program ACS-NSQIP dataset. Inclusion criteria were patients between 18 and 90 y of age who underwent TKA or THA. Patients were stratified into five BMI categories: normal, overweight, obese class I, obese class II, and morbidly obese. Demographic characteristics, length of stay, co-morbidities, and complication rates were compared across the BMI categories. RESULTS: A total of 1731 patients met the inclusion criteria, with 66% and 34% undergoing TKA and THA, respectively. A majority were female (60%) and >60 y (70%) in age. Of the patients who underwent TKA, 90% were either overweight or obese, compared with 77% in those undergoing THA. The overall preoperative comorbidity rate was 73%. The complication and mortality rates were 7% and 0.4%, respectively. When stratifying perioperative complications by BMI categories, no differences existed in the rates of infection (P = 0.368), respiratory (P = 0.073), cardiac (P = 0.381), renal (P = 0.558), and systemic (P = 0.216) complications. CONCLUSIONS: Our study demonstrates no statistical difference in perioperative complication rates in patients undergoing TKA or THA across BMI categories. Performing TKA or THA on patients with high BMI may increase mobility leading to improved quality of life.

J Bone Joint Surg Am. 2012 Aug 15;94(16):1501-8. The association between body mass index and the outcomes of total knee arthroplasty. Baker P1, Petheram T, Jameson S, Reed M, Gregg P, Deehan D. PMID: 22992819

BACKGROUND: In the United Kingdom, organizations involved in health-care commissioning have recently introduced legislation limiting access to total knee arthroplasty through the introduction of arbitrary thresholds unsupported by the literature and based on body mass index. This study aimed to establish the relationship between body mass index and patient-reported specific and general outcomes on total knee arthroplasty. METHODS: Using national patient-reported outcome measures (PROMs) linked to the National Joint Registry, we identified 13,673 primary total knee arthroplasties performed for the treatment of osteoarthritis...The improvement...was compared for three distinct groups based on body mass index (Group I [15 to 24.9 kg/m(2)], Group II [25 to 39.9 kg/m(2)], and Group III [40 to 60 kg/m(2)]) with use of multiple regression analysis to adjust for differences in age, sex, American Society of Anesthesiologists grade, general health rating, and number of comorbidities. RESULTS: The preoperative and postoperative patient-reported outcome measures declined to a similar extent with increasing body mass index. The gradient of the linear regression equation relating to the change in scores was positive in all cases, indicating that there was a tendency for scores to improve to a greater extent as body mass index increased...Wound complications were significantly higher (p < 0.001) at a rate of 17% (168 of 1018 patients) in Group III compared with 9% (121 of 1292 patients) in Group I. CONCLUSIONS: The improvements in patient-reported outcome measures experienced by patients were similar, irrespective of body mass index. Health policy should be based on the overall improvements in function and general health gained through surgery. Obese patients should not be excluded from the benefit of total knee arthroplasty, given that their overall improvements were equivalent to those of patients with a lower body mass index.

Obes Surg. 2016 May 17. [Epub ahead of print] Does Obesity Influence on the Functional Outcomes of a Total Knee Arthroplasty? Torres-Claramunt R1,2, Hinarejos P3,4, Leal-Blanquet J3, Sánchez-Soler JF3, Marí-Molina R3, Puig-Verdié L3,4, Monllau JC3,4. PMID: 27189353

BACKGROUND: The objective of this study was to compare the total knee arthroplasty (TKA) functional outcomes and quality of life of obese and non-obese patients. METHODS: Prospective comparative study, including all patients underwent TKA in a single centre. Patients were divided into three groups: Group 1 (Gr.1) BMI <30 kg/m2, Group 2 (Gr.2) BMI ≥ 30 kg/m2 and <35 kg/m2 and Group 3 (Gr.3) BMI ≥35 kg/m2. The Knee Society score (KSS) and SF-36 scores were obtained preoperatively and at 5 years of follow-up. RESULTS: A total of 689 patients were included (72.2 ± 7 years, 76.3 % women)...CONCLUSIONS: Although non-obese patients obtained better functional and reported quality of life scores than obese patients, there were no differences in the gain of quality of life and knee functionality between both groups at 5-years of follow-up. This is one of the largest series in a single centre published in literature and confirms the results obtained by other authors. Taking into account the different outcomes obtained, surgery should not be denied to patients that are obese, given that they obtained similar benefit than non-obese patients.