What are the Risk Factors for Failure after Conservative Treatment of Ulnar Collateral Ligament Injuries of the Elbow in Baseball Players?

Abstract

Objectives:Recovery from ulnar collateral ligament (UCL) injury of the elbow was previously thought to be beyond hope for baseball players. In recent years, however, surgical treatment of UCL injury in baseball players has resulted in a high return-to-play rate. Meanwhile, the effectiveness of rehabilitation as conservative treatment has been re-evaluated; many players can return to play by improving bodily functions and pitching forms without surgery. The factors that are cause adverse effect on conservative treatment and that bring them to surgery remain yet unclear. To identify the factors that affect to the results of conservative treatment, we prospectively compared the patients who were able to return to play with the patients who failed.Methods:From November 2009 to June 2012 (31 months), 295 baseball players were diagnosed with UCL injury at our facility. Of these, players with pain other than that due to UCL injury, those undergone rehabilitation less than 3 months, and those playing for recreation were excluded. 166 patients who have completed rehabilitation (>3 months) and who could be followed up at a competitive sport level were evaluated in this study. Eighty-two players (age, 16.0 ± 2.0 years) returned to competitive play with conservative treatment (succeeded group) and 84 (age, 18.9 ± 3.8 years) underwent to surgical treatment or could not return to competitive play (failed group). Factors for comparison included existence of ossicle in ligament, presence of symptoms of ulnar nerve disturbance during or after pitching, the extent of UCL injury (partial or complete) on magnetic resonance imaging (MRI), malunion of the medial epicondyle avulsed fragment, DASH sports, etc. They were compared using the statistical software SPSS 20.0.Results:There was an increased risk of negative results in patients with a residual ossicle (relative risk [RR] = 2.6, p<0.01), symptomatic ulnar nerve disorders (RR=2.2, p<0.01), complete UCL injury on MRI findings (RR 4.5, p<0.01) (Tables 1-3), period of pain and DASH score (p<0.01). Complete injury was the most significant factor. Though pitching was stopped for three months, it was a poor return rate of about 33 %. (Table 3) Players with these factors showed a significantly high probability of requiring UCL reconstruction surgery. On the other hand, 82% in players with partial injury could return to play with competitive level. (Table 3).Conclusion:We identified several baseline injuries that may increase the risk of adverse results of conservative treatment in patients with UCL injury in high level baseball players. In UCL injury with a residual ossicle of the ligament-bone junction, repeating sharp pain and remission readily leads to tear of the medial support structure and poor performance. Secondary ulnar nerve symptoms can result from medial instability by UCL injury during extended periods. Thus, these factors were considered to be refractory to conservative treatment. We believe that the results may help in evaluating candidates for surgery for UCL reconstruction.