Symptomatic Discoid Meniscus in Children and Adolescents: A Review of 470 Cases.

BACKGROUND: Discoid meniscus is a congenital variant, typically involving the lateral meniscus, that comprises a spectrum of meniscal shapes and degrees of instability in an estimated 1% to 15% of the population. The purpose of this study was to describe the clinical and operative course of a large cohort of children and adolescents patients with symptomatic lateral discoid meniscus. METHODS: Medical records of 470 knees with symptomatic lateral discoid meniscus in 401 patients ages 18 years or younger diagnosed at a single institution between 1991 and 2016 were reviewed retrospectively for patient characteristics, treatment course (nonoperative and/or operative), and complications. Surgical reports were reviewed in the operative group. RESULTS: The series included 401 patients of mean age 11.6 years (range: 1 mo-18.9 y), of which 222 (55%) were female, and 69 (17%) had bilateral involvement. Of 470 knees, 83 (18%) were initially managed nonoperatively. Of these, 32 knees (39%) failed nonoperative management and were converted to surgical treatment at a median of 7.9 months (interquartile range: 4.0-15.1). In total, 419 knees were managed surgically with saucerization (partial meniscectomy) with or without meniscal repair/stabilization; 84 knees (20%) required at least one concurrent nonmeniscal procedure. Discoid meniscus tears were reported in 264/419 knees (63%) intraoperatively; horizontal cleavage tears were most common. Reoperation was required for 66/379 cases (17%) with clinical follow-up, at a median of 19.6 months (range: 9.2-34.9) after index saucerization; 60/379 cases (16%) had ongoing pain and/or mechanical symptoms at final follow-up. CONCLUSION: With a failure rate of 39% (32/83 knees), nonoperative management for discoid lateral meniscus frequently convert to surgical treatment. During surgery, meniscus tearing and instability are common and should be anticipated. Postoperatively, 33% (126/379) of knees with clinical follow-up underwent either reoperation, or had ongoing symptoms of the knee at final follow-up. Discoid mensical retear is the most common complication (94%, 62/66) prompting repeat surgery, and should be discussed with families before the index operation. LEVEL OF EVIDENCE: Level IV-descriptive case series.

Reconstruction of Symptomatic Congenital Anterior Cruciate Ligament Insufficiency.

BACKGROUND: Hypoplasia or congenital absence of the anterior cruciate ligament (ACL) is a rare disorder occurring in ∼1 in every 6000 births. Although some patients with hypoplasia or agenesis of the ACL may not complain of instability, others desire to participate in more demanding activities that require the stability of a competent ACL. There are limited reports of surgical treatment of this patient population. The purpose of this study was to report ACL reconstruction in a case series of patients with symptomatic congenital ACL deficiency. METHODS: A retrospective medical record review of the surgical treatment of 14 knees (13 patients) with congenital absence of the ACL at a tertiary care institution from 1995 to 2012 was performed. Patients with a minimum of 1 year of clinical follow-up were eligible for inclusion. RESULTS: The mean age at time of surgery was 12.6 (range, 3 to 22), including 6 patients <12 years of age. Mean follow-up was 2.9 years (range, 1 to 6.6). Nine of 13 patients (69%) had underlying congenital abnormalities/associated syndromes. Preoperative Lachman and pivot shift examination was International Knee Documentation Committee grade C or D in all but 1 knee. ACL reconstruction was performed with combined intra-articular/extra-articular physeal sparing reconstruction with iliotibial band (n=5), autograft hamstring (n=2) or bone-patellar tendon-bone (n=3), or allograft (n=4). Multiligament reconstruction of associated ligamentous deficiency was performed in 7 knees (50%). Postoperative Lachman and pivot shift testing was International Knee Documentation Committee (IKDC) grade A or B in all but 1 knee. One patient with congenital absence of multiple knee ligaments required revision ACL reconstruction surgery, with concurrent first-time posterior cruciate ligament reconstruction, due to persistent instability. None required revision surgery due to graft tear at a minimum of 1-year follow-up. CONCLUSIONS: Surgical stabilization of symptomatic congenital ACL insufficiency, with associated ligamentous reconstruction as required on a case-by-case basis, results in improved stability at early clinical follow-up, with low complication rates. LEVEL OF EVIDENCE: Level IV-retrospective case series.