In a retrospective review of the results of 3,612 arthroscopic procedures that were performed for the treatment of an acute or a chronic meniscal lesion, with or without an associated ligamentous lesion, we identified eighty meniscal tears (in seventy-five patients) that had been assumed to be stable. Seventy were vertical longitudinal tears and ten were vertical radial tears. The seventy longitudinal tears included fifty-two lateral and eighteen medial meniscal lesions. All of the radial tears were in the lateral meniscus. Of the seventy-five patients, fifty-two had been followed for two to ten years. At the time of follow-up, only six of these fifty-two patients had needed additional intervention because of symptoms that were related to the meniscal tear. Four of them had the intervention after a sports-related traumatic extension of a stable tear, and two, because persistent symptoms were caused by the original meniscal lesion. A repeat arthroscopy was performed on thirty-two patients (twenty-six of whom had a longitudinal tear and six of whom had a radial tear), at an average of twenty-six months after the original arthroscopy. Seventeen of the twenty-six longitudinal tears had completely healed. Five of the six radial tears had no evidence of healing and one had extended. Neither ligamentous laxity nor a meniscal tear that was chronic at the time when it was discovered appeared to preclude healing of the stable longitudinal tears. No localized degenerative changes in the adjacent articular cartilage were found in association with any of the stable vertical longitudinal or radial meniscal lesions. Excluding the six patients who had had additional surgical treatment, none of the fifty-two patients who filled out a questionnaire reported that they had symptoms of a meniscal lesion, and none of the forty-two patients who were re-examined two years or more after the operation had signs of a meniscal lesion. Stable vertical longitudinal tears, which tend to occur in the peripheral vascular portions of the menisci, have great potential for healing. The tear should be left alone unless it is the only abnormality that is found and it is causing symptoms that warrant treatment. Stable radial tears, which tend to occur in the avascular inner one-third of the meniscus, have little potential for healing. Whether it is best to leave these lesions alone or to fashion an intact rim by contouring the meniscus was not established by this study.