Congenital Medial Meniscus Hypoplasia

Anomalous insertion of the anterior horn of the medial meniscus combined with anterior horn hypertrophy and a synovial cyst: case report and literature review

Objective

To gain a greater understanding of anomalous insertions of the anterior horn of the medial meniscus through evaluation of a rare case and a review of the existing literature on medial meniscus malformations.

Methods

This report describes a 26-year-old man with an anomalous insertion of the anterior horn of the medial meniscus combined with symptomatic hypertrophy of the anterior horn and a synovial cyst. We also conducted a review of the existing literature on medial meniscus malformations using five major scholarly literature databases and search engines.

Results

The literature review revealed that the incidence of anomalous insertions of the anterior horn of the medial meniscus is 0.5% to 2.8%. Not all patients undergo surgical excision; some are only symptomatically treated. In our patient, the arthroscopic view was consistent with the imaging characteristics. No special operation was performed to treat the anomalous insertion. At the 18-month follow-up, the patient had no symptom recurrence and had returned to practicing sports.

Conclusion

The pain during hyperextension in our patient was caused by a cyst and anterior horn hypertrophy. If the symptoms in such cases are not caused by the anomalous insertion, no special treatment is needed.

Bilateral Hypoplasia of Both Medial and Lateral Menisci Partially Fused With the Cartilage Surface of the Tibial Plateau

Hypoplastic meniscus is an extremely rare abnormality. The authors present the first case of meniscal hypoplasia with a partial fusion of meniscus and tibial cartilage. A 22-year-old man underwent surgery for a chronic patellar dislocation. Preoperative magnetic resonance imaging and arthroscopy incidentally revealed hypoplasia of both medial and lateral menisci. Moreover, the posterior horn of the medial meniscus and middle body of the lateral meniscus were fused with the cartilage surface of the tibia. Magnetic resonance imaging of the contralateral knee showed similar meniscal anomalies. This case presents an interesting and extremely rare abnormality of the meniscus. [Orthopedics. 2018; 41(6):e884-e887.].