Heterotopic calcification and tears of the ulnar collateral ligament: Radiographic and MR imaging findings

OBJECTIVE. The purpose of this paper is to describe the radiographic and MR imaging appearance of heterotopic calcification in the ulnar collateral ligament. MATERIALS AND METHODS. Retrospective radiographic review of 710 patients examined for elbow pain yielded 42 individuals (age range, 16-38 years) with heterotopic calcification in the ulnar collateral ligament. Radiographic and MR imaging findings were compared with surgical findings. RESULTS. Fifty-one heterotopic calcifications were identified in 42 patients; nine patients had two sites of heterotopic calcification. Average initial calcification size in the craniocaudal dimension was 4 min (range, 1-12 mm) and in the transverse dimension was 1 mm (range, 1-4 mm). Five of 42 patients had enlargement of the calcification on follow-up radiography. The largest heterotopic calcification that was not visualized on MR imaging measured 5 x 4 mm in craniocaudal and transverse dimensions. Of 34 patients with heterotopic calcification who underwent surgery, 26 patients (76%) had either partial or complete tears of the ulnar collateral ligament. CONCLUSION. Heterotopic calcification in the ulnar collateral ligament may be associated with partial or complete tears. The MR imaging detection of heterotopic calcification is less sensitive than that of radiography of the elbow.