We assessed the accuracy of magnetic resonance imaging in detecting clinically significant lesions of the anterior horn of the meniscus by reviewing 947 consecutive knee magnetic resonance imaging reports. Of these, 76 (8%) indicated a tear of the anterior horn of the medial or lateral meniscus. Thirty-one of these 76 patients underwent a subsequent arthroscopic examination, and their operative reports were reviewed. The 45 patients who were not examined arthroscopically were contacted and interviewed for clinical follow-up. Among the 31 patients who underwent arthroscopic examination, 8 anterior horn tears were noted in the predicted area (26% true-positive results), 23 patients had intact anterior horns (74% false-positive results), and 18 had normal intact menisci in all zones. Of the 45 patients who did not undergo arthroscopic surgery, 6 had isolated anterior horn tears reported on magnetic resonance imaging, and 5 of the 6 were asymptomatic at follow-up. The other 39 patients had multiple pathologic conditions noted on the magnetic resonance imaging report and continued to report knee pain at the follow-up interview. Increased signal intensity at the anterior horn of the meniscus seen on magnetic resonance imaging commonly does not represent a clinically significant lesion. We recommend correlation with the physical examination when interpreting this "positive" finding on knee magnetic resonance imaging examinations.

Stability of the thumb metacarpophalangeal joint is provided by the collateral ligament proper, the accessory collateral ligament, the proximal and distal palmar ligaments, and the palmar plate. The adductor pollicis and flexor pollicis brevis muscles also provide soft tissue support and insert on the proximal phalanx of the thumb by way of the sesamoid bones. Fractures of the metacarpophalangeal joint sesamoid bones are uncommon but are often associated with sporting injuries during which the joint is acutely hyperextended. Routine anteroposterior and lateral radiographs may be unremarkable, and oblique views are often necessary to document the fracture. We report eight cases of fracture of the thumb metacarpophalangeal joint sesamoid. Seven were isolated sesamoid fractures, and one was associated with a metacarpophalangeal joint dislocation. None of the fractures were evident on anteroposterior radiographs, but all were seen in the oblique projection. Six fractures were treated with splint or cast immobilization for 2 to 3 weeks, and two were taped. Clinical followup of the seven patients with isolated sesamoid fracture at 6 to 8 weeks revealed pain-free normal function. One patient could not be reached for followup.