The effect of sarcopenic obesity on knee biomechanics in individuals with end-stage knee osteoarthritis.

Background: It is unclear how knee biomechanics in individuals with Sarcopenic Obesity and osteoarthritis (OA-SO) affect ambulation relative to those with knee osteoarthritis (OA) without SO. The primary objective of this study was to compare the knee kinematics and spatio-temporal gait parameters during treadmill walking using simulated terrain modifications in individuals with end-stage knee OA awaiting total knee arthroplasty (TKA) with SO and obesity (OA-SO group) versus those with knee OA without SO (OA group).

Methods: We performed a cross-sectional analysis of individuals with knee OA (with or without SO) awaiting TKA. Gait assessments using Computer-Assisted Rehabilitation Environment (CAREN) occurred within one month before TKA; each participant was asked to perform two trials of self-selected treadmill speed for each of the following six walking conditions: (1) level; (2) uphill; (3) downhill; (4) cross slope with the affected body side elevated; (5) cross slope with the unaffected side elevated; and (6) medial-lateral walking surface translations. Data analyses compared demographics, gait kinematics, spatio-temporal, and clinical outcome measures between the groups using a two-tailed independent t-test for continuous measures and Chi Square tests for categorical data.

Results: The groups were similar in age and sex distribution (P = 0.90 and 0.37, respectively). Of the 18 participants with knee OA, eight were classified as with and ten without SO. On the affected side, the group-level knee flexion-extension range was significantly larger in the OA group compared to OA-SO group for all six walking conditions during the full gait cycle. The OA group walked significantly faster than the OA-SO group for all walking conditions. The stride length and step length were significantly longer in the OA group than in the OA-SO group during four of the six walking conditions.

Conclusion: Gait assessment for different walking conditions adds important information to level walking assessments. Individuals with knee OA and SO have less knee range of motion, are slower, and less stride and step length, compared to individuals with OA only. This study may indicate the need for preoperative and postoperative rehabilitation programs to address the needs of individuals with knee OA and SO.