Total Knee Not a Weight Loss Panacea?

Postop slimmer you? Perhaps not, say researchers. The team, led by Maria Inacio, M.S., a doctoral candidate from the San Diego State University/University of California, San Diego, conducted a review of the current literature to find out. Their results appear online in the journal Clinical Orthopaedics and Related Research, published by Springer.

The authors conducted a review of 12 studies meeting their criteria. They considered the studies thus far in this area to be of generally low quality with small sample sizes and poor methods, leading to a risk of bias. Overall the studies reported between 14% to 49% of patients had lost weight a year after having a TJA (total joint arthroplasty). However, the ranges of weight loss suggested inconsistent loss and the differences in the study designs meant that overall there was no conclusive pattern. In fact, the studies showed that more patients gained weight than lost.

In a CORR Insights commentary on the manuscript, Stuart B. Goodman, M.D., Ph.D., of Stanford University said, “Obese patients frequently tell clinicians that they are overweight because their painful hips or knees limit their physical activities and their capability to ‘burn calories.’ Unfortunately, after a comprehensive analysis of the data, the answer to this important question is still unknown.”

Inacio, who is employed at Kaiser Permanente, told OTW,

This article is the first product from my PhD dissertation. I am currently conducting a study trying address the questions raised by this study and bring more clarity to the issue. Regarding what else needs to be done, a better understanding of how obesity affects this special population is necessary, both pre-operatively and post-operatively. From our review of the literature it is not clear that patients should expect total knee replacements to help them lose weight. We recommend that larger high quality studies be conducted to better characterize the patients undergoing total knee replacements and their historical and post-operative weight patterns. We hope that once patient characteristics and their associations with weight patterns are understood, this information can be used by clinicians/providers to personalize weight management interventions.