Joint Reaction Forces Decrease Following Total Knee Arthroplasty up to 12‐Months Post‐Surgery

) during level gait and sit-to-stand at each timepoint. Medial, lateral, and total JRF peak values and impulses reduced significantly postoperatively at 3-months and did not return to preoperative values at 12-months for either activity. During level gait, mean total JRF peak values reduced by 0.72 BW (p < 0.001) (medial mean difference: 0.39 BW, p < 0.001; lateral mean difference: 0.23 BW, p < 0.001) at 3-months post-surgery. A similar trend was observed in the sit-to-stand activity with a mean decrease of 0.44 BW in the peak total JRF at 3-months (p < 0.001). Impulse values followed a similar trend to the peak values. Clinical relevance: People do not return to preoperative JRFs even at 12-months post-TKA, and this may be a contributing factor for previously reported decreases in BMD around femoral and tibial components.