BMI Impacts Long-Term Outcomes of Partial Knee Replacement

WEDNESDAY, March 29, 2023 (HealthDay News) -- Patients with higher body mass index (BMI) have higher revision rates for cemented unicompartmental knee replacements (UKRs), but not for the cementless UKRs, according to a study published online March 7 in the Journal of Bone & Joint Surgery.

Hasan R. Mohammad, D.Phil., from the University of Oxford in the United Kingdom, and colleagues examined the relative performance of cementless fixation in patients of different BMIs undergoing UKRs. The analysis included 10,440 propensity-matched cemented and cementless UKRs.

The researchers found that the revision rate per 100 component-years significantly increased with BMI for the cemented UKRs (normal weight: 0.92; overweight: 1.15; obese: 1.31). However, for cementless UKR, revision rates were 1.09, 0.70, and 0.96, respectively. The 10-year implant survival rates for the matched cemented and cementless UKRs were 93.8 versus 94.3 percent (hazard ratio, 1.17) in the normal-weight group, 88.5 versus 93.8 percent (hazard ratio, 0.61) in the overweight group, and 90.7 versus 91.8 percent (hazard ratio, 0.74) in the obese group. In the cementless group, patients with obesity had less than half the rates of aseptic loosening (0.46 versus 1.31 percent) and pain (0.60 versus 1.20 percent) compared with the cemented group.

"The present study suggests that cementless fixation may be better suited for overweight and obese patients, which is an important finding given an increasingly overweight population requiring knee replacement," the authors write.

One author disclosed financial ties to the pharmaceutical industry; one author disclosed various patents relating to unicompartmental knee replacement.

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