Prevalence and clinical outcomes of heterotopic ossification after ulnar collateral ligament reconstruction.

Background: Ulnar collateral ligament (UCL) reconstruction has become increasingly popular in elite athletes. However, the prevalence of heterotopic ossification (HO) formation after UCL reconstruction has not yet been reported. We sought to determine the prevalence of HO formation after UCL reconstruction and the clinical outcomes following HO treatment.

Materials And Methods: From October 2005 to April 2014, 179 patients underwent primary UCL reconstruction. Of the 179 patients, 161 with a minimum of 2 years of follow-up were retrospectively reviewed to evaluate HO formation and clinical outcomes.

Results: Among 161 patients, HO was detected in 8 cases (5%). Of these 8 patients, 2 were asymptomatic and another 2 complained about transient ulnar neuropathy. The remaining 4 patients had pain; 2 were treated with open excision, and 1 underwent arthroscopic excision. The odds of HO in patients in whom transient ulnar neuropathy develops after UCL reconstruction are 6 times higher than those without transient ulnar neuropathy (odds ratio, 5.957; 95% confidence level, P = .04). Of the 8 patients, 7 returned to the same level or a higher level of competition. HO was found, on average, 5 months (range, 3-9 months) after UCL reconstruction.

Conclusion: The prevalence of HO formation was approximately 5% after UCL reconstruction and increased with transient ulnar neuropathy. After UCL reconstruction, the surgeon should carefully observe HO formation, especially in the early stages after the operation. With appropriate treatment, the clinical outcomes of HO treatment after UCL reconstruction are favorable.