The natural history of the knee following arthroscopic medial meniscectomy

We examined the natural history of arthroscopic medial meniscectomy in knee s with an isolated meniscal injury by reviewing 317 of 894 cases following medial meniscectomy. At the time of the initial surgery none of the knees h ad been operated on, and there was no evidence of ligament injury. The pati ents were reviewed clinically and radiologically after a mean of 11.5 years (range 10-15). The knee was considered "normal" or "nearly normal' by 91% of patients. In 218 patients the contralateral knee was asymptomatic withou t history of operation or significant injury and could be used as control f or comparison. Radiology showed 22.4% greater excess prevalence of joint sp ace narrowing in the operated compared to the control knee. The factors pre disposing to a poor radiological result were age above 35 years, the presen ce of medial compartment cartilage degeneration at the time of the first ar throscopy, resection of the posterior one-third of the meniscus, and menisc al rim resection. Preoperative participation in sport was a predictor of a better outcome.