Muscle activity while ambulating on stairs and slopes: A comparison between individuals scheduled and not scheduled for knee arthroplasty and healthy controls

Objective: To examine muscle activity patterns of the lower limbs while ascending and descending stairs and slope in adults with knee Osteoarthritis (knee-OA), who were scheduled or not scheduled for Total Knee Replacement (TKR) and healthy controls. Methods: This cross-sectional study included three groups: knee-OA subjects scheduled for TKR (TKR group; N = 15) and not scheduled for TKR (NTKR group; N = 15) and age-matched controls (N = 11). Outcome measures included: joint range of motion (ROM), Timed Up and Go (TUG), joint pain levels, and functional disability (Oxford) score. Also, durations of muscle activity (rectus femoris, semitendinosus, medial gastrocnemius, bilaterally, and soleus, and tibialis anterior of the OA limb) were recorded while the subjects ascended and descended stairs and a level surface. Results: Both knee-OA groups had significantly higher Oxford scores and bilateral knee pain levels compared to the control group. The TKR group had higher TUG score compared to the NTKR group. The activation duration of the Tibialis Anterior of the OA limb while ascending and descending stairs and slope were higher in the TKR group compared to the NTKR group. No differences in muscle activity durations were found when comparing the OA limb to contralateral limb. Conclusion: The muscle activity strategies differentiated between individuals scheduled and not scheduled for TKR. The longer duration of muscle activity of Tibialis Anterior muscle in the TKR group compared to the NTKR group suggest that customized prehabilitation program is required for these groups.