Early Joint Use Following Elbow Dislocation Limits Range-of-Motion Loss and Tissue Pathology in Posttraumatic Joint Contracture

Background: Simple elbow dislocation occurs at an incidence of 2.9 to 5.21 dislocations per 100,000 person-years, with as many as 62% of these patients experiencing long-term elbow joint contracture, stiffness, and/or pain. Poor outcomes and the need for secondary surgical intervention can often be prevented nonoperatively with early or immediate active mobilization and physical therapy. However, immobilization or limited mobilization may be necessary following trauma, and it is unknown how different periods of immobilization affect pathological changes in elbow joint tissue and how these changes relate to range of motion (ROM). The purpose of this study was to investigate the effects of varying the initiation of free mobilization on elbow ROM and histological features in an animal model of elbow posttraumatic joint contracture. Methods: Traumatic elbow dislocation was surgically induced unilaterally in rats. Injured forelimbs were immobilized in bandages for 3, 7, 14, or 21 days; free mobilization was then allowed until 42 days after injury. Post-mortem joint ROM testing and histological analysis were performed. One-way analysis of variance was used to compare ROM data between control and injured groups, and Pearson correlations were performed between ROM parameters and histological outcomes. Results: Longer immobilization periods resulted in greater ROM reductions. The anterior and posterior capsule showed increases in cellularity, fibroblasts, adhesions, fibrosis, and thickness, whereas the measured outcomes in cartilage were mostly unaffected. All measured histological characteristics of the capsule were negatively correlated with ROM, indicating that higher degrees of pathology corresponded with less ROM. Conclusions: Longer immobilization periods resulted in greater ROM reductions, which correlated with worse histological outcomes in the capsule in an animal model of posttraumatic elbow contracture. The subtle differences in the timing of ROM and capsule tissue changes revealed in the present study provide new insight into the distinct timelines of biomechanical changes as well as regional tissue pathology. Clinical Relevance: This study showed that beginning active mobilization 3 days after injury minimized posttraumatic joint contracture, thereby supporting an immediate-motion clinical treatment strategy (when possible). Furthermore, uninjured but pathologically altered periarticular tissues near the injury location may contribute to more severe contracture during longer immobilization periods as the disease state progresses.