Though weight loss is encouraged prior to a total knee replacement, there are surgeons who’ll operate on someone who’s 300 pounds.

Recovery will typically be more arduous simply because of all the excess weight.

“Total knee replacements in obese patients can produce good functional recovery, but many reports favor less favorable outcomes among obese patients and higher complication rates,” says Marc F. Matarazzo, MD, a board certified orthopedic surgeon with The Center for Bone & Joint Surgery of the Palm Beaches, FL.

“In general, obese patients undergoing total knee arthroplasty experience higher revision rates and higher perioperative complications such as decreased wound healing, increased wound infections, increased joint infections, increased loosening of the implants and increased wear of the implants.

“These complications are well-known to increase healthcare costs and affect value-based care in which financial penalties are incurred for patients with complications.

“Many surgeons can be dissuaded from accepting these potential risks, which can lead to a disparity in access to care.

“When faced with an obese patient considering total knee replacement, a surgeon must evaluate the patient as a whole and not just the obesity.

“One of the main problems is that obesity is associated with other comorbidities that can also increase the risk of peri- and postoperative complications, such as diabetes, hypertension, coronary artery disease, respiratory problems, etc.

“This is why informed consent is of paramount importance when treating these patients.”

Obesity, in and of itself, without any consideration for other aspects of the patient including their medical history, should not be a deal breaker.

An obese middle age person may actually be free of diabetes and respiratory problems; may have normal blood pressure and no signs of coronary artery disease. Their only problem as far as disease is the osteoarthritis.

A projected surgical outcome for them would be much more favorable than for a similar size and age patient who has non-alcoholic fatty liver disease, early heart failure and a long history of smoking.

Chronic obesity, especially morbid, even in nonsmokers, usually comes with other challenges that can lead to postop complications – either immediate or months out such as loosened implants.

The older the patient who’s 300 pounds, the more likely he or she will have several comorbidities.

What a Morbidly Obese Person Can Expect Immediately After TKR

If there was pre-existing mobility impairment due to the patient’s weight, then postop ambulation will still be affected by this.

TKR patients are urged to be walking as soon as possible to prevent blood clots – for which obesity is an independent risk factor.

If someone is morbidly obese, everything is more difficult, from going up steps to getting in and out of cars and deep chairs, to various household tasks, bending over to pick up toddlers and so many other elements of daily existence.

“One would consider all activities of daily living (ADLs) as likely being more difficult for an obese patient after this surgery, in addition to social factors such as living arrangements (stairs, parking, etc.), family members to help, home modifications such as elevated toilet seats, shower stools, etc.,” says Dr. Matarazzo.

When you add a recent total knee replacement to the general mobility difficulties of morbid obesity, you can see how it’ll just take longer for recovery as well as the recovery process being more taxing.

For example, even if a healthy-weight person just had a TKR, they’ll need a booster seat on the toilet to lessen knee flexion when sitting and rising.

If someone at 5’7 weighs 300, rising off even a booster seat – soon after a TKR – will prove far more challenging than if that person weighed 150.

Even if the patient uses a metal bar to push off of with their hands, or a device to pull on to rise from the seat, all that extra body weight will make these tasks a lot tougher.

It’s all about gravity. What a 300 pound TKR patient faces after they get home from the hospital is a harder time getting around on their “new knee,” when compared to a much lighter version of themselves.

If there’s a staircase in the house that the patient must navigate, 150 extra pounds will make this all the more difficult during the recovery process.

The recovery process can take three months on average for even a person with a normal body mass index.

“Oftentimes a social worker or case manager could help in evaluating and coordinating these [modified living arrangements],” says Dr. Matarazzo. 

“Also, one may consider acute inpatient rehab or a skilled nursing facility to assist in care early on.”

Patients of all sizes must be diligent about taking their prescribed blood thinners and doing their assigned physical therapy, as well as avoiding activities that they were instructed to avoid.

Dr. Matarazzo specializes in sports medicine and related injuries. He performs minimally invasive and complex reconstructions, and joint replacements, of the shoulder and knee. Dr. Matarazzo is certified in the MAKO robotic-assisted knee replacement system and has 20+ years of orthopedic experience. He has a special interest in cartilage restoration and preservation.
Lorra Garrick is a former personal trainer certified by the American Council on Exercise. At Bally Total Fitness she trained clients of all ages for fat loss, muscle building, fitness and improved health.