Bariatric surgery when combined with dietary and exercise management resulted in signifcant weight loss, reducedd knee pain and improved functions. With this approach, both obesity and osteoarthritis (OA) issues can be taackled. It is a major step forward in stemming the global epidemic of these two interlinked conditions.

In both developed and developing countries, at least 2.8 million adults died due to excess body weight. Therefore, obesity is considered to be the fifth leading risk factor for deaths worldwide. The numerous types of co-morbidities are reported to be associated with obesity such as diabetes, dyslipidemia, obstructive sleep apnea, hypertension and joint pain of knee and back. Recently, the association of obesity with diabetes has been increased with an alarming rate. According to the World Health Organization (WHO), approximately 1 billion people are overweight, and amongst them 300 million are obese. Obesity is known to be the most significant risk factor for the development of osteoarthritis (OA). The obese people are four times more likely to have knee OA than those with healthy weight.

Various studies found that weight loss in OA patients leads to a significant improvement in their OA symptoms. An observational study conducted by Framingham et al showed that only 5 kg reduction in body weight decreases the risk of developing knee OA. One more review by Messier et al also showed similar results, but they used combinations of diet and exercises weight reduction process in their study. With the increased prevalence of obesity, a need for joint replacement surgery was found to increase. Total knee replacement (TKR) is a highly prevalent and expensive surgical procedure. Although TKR helps in reducing pain in most patients, it does not resolve many of functional limitations associated with chronic knee arthritis that existed before the surgery. For the obese patients, the bariatric surgery came as a boon that removes up to 60-70% of excess body weight by changing the digestive system's anatomy and limiting the amount of food. Also, it significantly reduces the knee pain in OA patients.

Therefore, in the present study, the role of bariatric surgery with dietary and exercise changes on knee pain in overweight and morbidly obese OA patients making a way to delay the need for knee replacement was evaluated.

Rationale behind the research:

Various studies determined the beneficial effect of bariatric surgery on the knee OA, but none of the studies evaluated the synergistic effect of surgery and lifestyle modifications on the progress of OA.

Therefore, in the present study, Lajja Rishi et al. evaluated the combinational effect of bariatric surgery and dietary and exercise modifications on the development of knee OA.

Objective:

To find the weight reduction pattern and its outcome on knee pain and function in OA morbidly obese patients’ post-bariatric surgery with dietary and exercise changes. 

Study outcome measures:

• Western Ontario and McMaster Universities Arthritis Index (WOMAC): A standardized self-administered questionnaire, was used to evaluate both development and progression of OA. It comprised 24 questions (5 - pain, 2 - stiffness and 17 - physical functioning). WOMAC score was taken at baseline, 3 months and after 6 months of follow-up.
• The types of bariatric surgery performed were laparoscopic sleeve gastrectomy (LSG-12), mini gastric bypass (MGB-12) and Roux-en-Y gastric bypass (RYGB-6)
• A fixed 5-exercise protocol for knee OA with Mulligan mobilization was formed by bariatric physiotherapist (LR) that also included fixed ambulation in whole day both pre and postoperatively with proper knee cap and sports shoes mandatory 

Time period:  Baseline, 3 months and 6 months.

Study Outcomes

• Western Ontario and McMaster Universities Osteoarthritis Index:

As a result of bariatric surgery, there is as significant reduction in weight and BMI after 3 and 6 months postoperatively (p<0.0001). There was also a significant reduction in pain, stiffness and ADL after 3 and 6 months postoperatively (Figure 1).

Figure 1: Comparing average body mass index, pain, stiffness and activities of daily livings

• Correlation of percentage BMI change with percentage change in pain, stiffness, activities of daily living:

Significant correlation of percentage changes in BMI with percentage change of pain (r=0.479, P=0.007) and ADL (r= 0.414, P= 0.023) was observed. However, no correlation was seen with percentage stiffness change (r=−0.175, P=0.356).

• Correlation of type of surgeries with percentage change in weight reduction, body mass index:

On comparing the types of surgery with respect to 6^th-month weight loss, change in BMI and WOMAC score parameters, all the surgeries (LSG, MGB and LGB) gave insignificant results showing that all the surgeries are equally capable of reducing weight and improving BMI.

In this study, it seemed that bariatric surgery is beneficial for weight-bearing knee joint paint. Obesity-related OA is multifaceted, can be due to the mechanical factor, which includes increased pressure on the joint, which results in decreased joint space, muscle strength and altered biomechanics. Another one the aging and metabolic factor in which adipokine levels produce the biomechanical environment where chondrocytes do not respond to challenges.

Numerous studies have found the moderate-to-strong correlation between knee OA and obesity. With the advanced technology, the surgical management of knee pain has developed, i.e., knee replacement. But the outcome was also questionable due to intra- and post-operative reasons such as higher incidence of wound dehiscence, superficial infections, thromboembolic events, higher intraoperative blood loss leading to longer operative time, early failure, high revision rates and malposition of implants.

On the other hand, the outcome of bariatric surgery before orthopedic surgery reported being effective in weight loss, and many orthopedic surgeons prefer this in managing obesity before performing knee replacement surgery. The results of the current study showed a significant positive correlation between BMI and pain. Supportive research showing the effect of weight reduction on eighty knee OA patients found that with 10% weight reduction, the function was increased by 28%. Maybe future research and the follow-up study is needed to see the long-term change of weight reduction on stiffness and need for TKR.

In addition, the combination of protein-rich diet and physical exercise provides symptomatic relief from the knee pain. Therefore, researchers encouraged the patients to continue knee exercises further with some modifications to overcome degenerative changes due to aging in future.

Bariatric surgery with dietary and exercise changes is an important tool for both prevention and management of obesity with OA.