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

Abstract

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.