Arthroscopic treatment of symptomatic discoid meniscus in children.

PURPOSE: To study discoid meniscus in children who underwent arthroscopic surgery at our center.

SUBJECTS AND METHODS: Thirty-four patients (39 knees) younger than 15 years with discoid lateral meniscus (mean age, 12.9 years; 13 males, 21 females) who underwent arthroscopic surgeries since 2007 were studied. The surgical procedure consisted of, in principle, saucerization with additional suture repair in the case of meniscal instability at the peripheral rim of the residual meniscus. The mechanisms of symptom onset, symptoms, complications and postoperative outcome in these cases were examined. In addition, Lysholm scores were obtained before surgery and at the last postoperative follow-up in all patients.

RESULTS: Symptom onset was associated with sports in 18 knees, fall in 3 knees, and no definitive trigger in the remaining knees. The presenting symptoms were pain in 32 knees, catching in 11 knees, and locking in 6 knees. According to Watanabe classification, 26 knees were complete type and 13 knees were incomplete type. The modes of tear included horizontal tear in 10 knees and longitudinal tear in 10 knees, while no definitive tear was present on the knee joint surface. The surgical procedures included saucerization only in 22 knees, partial meniscectomy in 10 knees, and saucerization with suture repair in 5 knees. The mean Lysholm score was 63.9 before surgery, and improved significantly to 92.3 at the last follow-up. Only two knees developed osteochondritis dissecans after surgery. Two knees required reoperation; one knee underwent subtotal meniscectomy and one knee had partial meniscectomy with suturing.

CONCLUSION: Although the short-term outcome after saucerization with or without suture repair for discoid meniscus is favorable, degenerative change or change of lower limb alignment may occur in the long term. Further long-term study is required.