Is minimally invasive surgery-total knee arthroplasty truly less invasive than standard total knee arthroplasty? A quantitative evaluation.

With recent technical advancements, the number of operative manipulations in the knee joint by minimally invasive surgery-total knee arthroplasty (MIS-TKA) is now considered to be the same as that using standard TKA (S-TKA). The question still remains, however, if MIS-TKA improves recovery compared to S-TKA. We compared MIS-TKA and S-TKA patients' physical activity as measured by an accelerometer. Physical activity expressed as cumulative acceleration was significantly higher in the MIS-TKA than in the S-TKA group on postoperative days (POD1, 2, 3, 4, 5, 10, 11) (P < .05). The recovery time, defined as the number of days required to achieve cumulative acceleration of 80% of the preoperative level, was significantly shorter (P < .05) in the MIS-TKA (3.0 +/- 3.3 days) group than in the S-TKA (7.0 +/- 3.5 days) group. Minimally invasive surgery-total knee arthroplasty appears to allow an earlier recovery after the operation than S-TKA. Less invasion to muscle during the surgery appears to contribute to shorter convalescence.