Soft tissue constraint injuries in complex elbow instability: prevalence, pathoanatomy, and classification.

The types and prevalence of soft tissue constraint injuries associated with complex elbow instability have been rarely investigated. The purpose of this study was to analyze the intraoperative findings of soft tissue constraint injuries in complex elbow instability and provide a comprehensive classification of these lesions. Forty-seven patients undergoing surgery for complex elbow instability were prospectively analyzed. Ligament injuries were classified as simple or complex lesions, depending on whether the ligament was damaged at a single zone or 2 to 3 zones, including its proximal, middle, and distal portions. Posterolateral capsule injuries were classified as small or large in the presence of capsular avulsions smaller than or larger than 1 cm, respectively. The presence of lesions of the common extensor and flexor-pronator muscles were also recorded. Ligament injuries were found in 96% of patients. The lateral collateral ligament showed a simple lesion, including a proximal and distal avulsion, in 19% and 2% of patients, respectively, and a middle-zone tear in 13%. Complex lesions, including the association of a middle-zone tear with a proximal or distal avulsion, were found in 47% and 6% of patients, respectively, and a combination of proximal, distal, and middle-zone injuries in 4%. Small and large posterolateral capsule lesions were found in 49% and 17% of patients, respectively. A medial collateral ligament injury was present in 45% of patients. A high prevalence of soft tissue constraint lesions was found to be associated with complex elbow instability. Soft tissue constraint status should be carefully evaluated pre- and intraoperatively in patients with complex elbow instability. The classification reported herein may be helpful in planning the proper treatment of these complex injuries.