Radial tears of the posterior horn of the medial meniscus.

PURPOSE: The purpose of this study was to introduce clinical features and characteristics of radial tears of the posterior horn of the medial meniscus and the results of arthroscopic surgery. TYPE OF STUDY: Retrospective case series.
METHODS: From August 1996 to December 1999, 345 consecutive cases of medial meniscal tears were treated using arthroscopic surgery in Asan Medical Center, Seoul, Korea. Of these, 96 cases (27.8%) with radial tears of the posterior horn of the medial meniscus were reviewed. All patients were treated with arthroscopic partial meniscectomy. Based on medical records, including surgical notes and detailed arthroscopic photographs, we reviewed the age distribution of the patients, preoperative physical signs, magnetic resonance imaging, surgical findings, and clinical results using the Lysholm Knee Scoring scale and our own questionnaire.
RESULTS: Radial tears of the posterior horn of the medial meniscus were more common than previously known and also were more common in elderly patients. Most patients presented mechanical symptoms. Magnetic resonance imaging often failed to reveal the tears. Careful attention to the nature of pain and the physical examination was critical in making a diagnosis. Although most patients were elderly and had degenerated articular cartilages, subjective symptoms improved significantly after arthroscopic partial meniscectomy.
CONCLUSIONS: Radial tears of the medial meniscus posterior horn are common. Diagnosis of this tear is often difficult because most patients have osteoarthritic knees masking meniscal tears and magnetic resonance imaging shows unacceptably high rates of false-negative results. Following strict surgical indications, arthroscopic partial meniscectomy can help patients with low morbidity. LEVEL OF EVIDENCE: Level IV therapeutic study (case series, no or historical control group).