Introduction: Instability of the anterior horn of the medial meniscus (MM) has been described as dislocating, subluxating or hypermobile, but it is still controversial whether segments of the MM of the knee were surgically treated by arthroscopic stabilization. The average age of the patients was 28.7 (range 12 to 56). There were 9 men and 4 women. All patients complained of medial knee pain and felt tenderness in the medial joint space, most of them on the anterior side. None showed an apparent tear of the meniscus by arthroscopy or on MRI images, but all arthroscopically showed hypermobility (or easy dislocation from the edge of the tibial plateau) of the anterior to middle segment of the MM. No other apparent pathological changes were found. Six knees had marked limitations in the range of knee motion before operation. Arthroscopic stabilization of the hypermobility was performed in order to restrain the movement of the MM by fixing it to the tibial edge, using staples (2 cases), Kirschner wires (2 cases) or suture anchors (9 cases). Using the Japanese Orthopaedic Association meniscus injury score (maximum 100 points), the result was evaluated. The average follow up period was 20.1 months (range 9 to 49 months)

Results: The result of arthroscopic fixation was satisfactory (excellent in 8 cases good in 1, fair in 1, and poor in 1). The average meniscus score at follow up was 87.8, while that of before operation was 41.9. It is suggested that instability of the anterior segment of the MM can be effectively treated by arthroscopic fixation of this site.

Discussion: Since all of the knees in this study had an isolated lesion of instability in the anterior segment of the MM, the marked improvement in medial knee pain that resulted from fixation of this site does show that this lesion can be symptomatic. After excluding other possible pathological lesions, stabilization of this lesion by arthroscopic fixation is a good choice of treatment.