Long-term follow-up of arthroscopic treatment of discoid lateral meniscus in children

Objectives: The discoid meniscus, occurring almost exclusively on the lateral side, can lead to pain, popping, snapping, and decreased knee extension. The purpose of this study was to examine the long-term clinical outcomes of arthroscopic partial meniscectomy for the treatment of discoid lateral meniscus in children. Methods: A previous study at our institution identified 27 consecutive patients who underwent arthroscopic meniscal saucerization by one of two surgeons between 1997 and 2002. These patients were included in this study if they were willing and able to complete the five outcomes questionnaires (IKDC Subjective Knee Evaluation, Kujala Scoring Questionnaire, Lysholm Knee Scoring Scale, Marx Activity Rating Scale and Tegner Activity Scale). Seven additional patients that were treated consecutively at least 10 years ago were also included in the study. Patients were also given the opportunity to receive a knee exam performed by one of the two treating surgeons. The exam was documented as per the IKDC knee examination protocol. Associations between outcome scores and discoid type, meniscal stability, location of instability, and age at time of surgery were identified. Results: Of the 34 eligible patients (23 female, 11 male), 22 patients were contacted, and 21 agreed to participate. The average length of follow-up was 13.7 years, ranging from 10.3 years to 16.6 years. Average age at the time of surgery was 9.3 years. Long-term follow-up revealed average IKDC, Kujala, and Lysholm scores of 82.87, 86.63 and 83.73, respectively. Additionally, average Marx and Tegner scores were 5.36 and 5.63, respectively. Stratifying the Lysholm scores revealed outcomes that were 45.4% excellent, 18.2% good, 27.3% fair, and 9.1% poor. The average IKDC Knee Examination score was A (normal). In total, 20.6% (7 of 34) of eligible patients underwent a subsequent surgical procedure on the affected knee. Conclusion: Numerous studies have demonstrated good to excellent short-term outcomes after arthroscopic treatment of discoid meniscus. At an average follow-up of nearly 14 years, our data suggests that clinical outcome scores decline over time. Compared to our previous study with 2-year follow-up, there is an increased rate of knee pain, mechanical symptoms, and functional limitations. Despite excellent postoperative IKDC examination scores, approximately 40% of our patient cohort demonstrated relatively low Lysholm scores (fair and poor).