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Background: Controlled joint extension followed by gradual distraction with use of an external fixator may facilitate primary repair of peripheral nerve defects by permitting end-to-end repair without tension. The hypothesis of the present study was that gradual lengthening of nerve repairs with use of incremental distraction would provide superior results compared with grafting or repair under tension. Methods: A median nerve segment measuring four times the diameter of the nerve was resected in thirty-six rabbits to create a 7-mm gap in the nerve. Neurorrhaphy was performed with use of one of three techniques. In Group 1 (cable graft), a tension-free medial antebrachial cutaneous graft was placed to allow full range of motion of the elbow postoperatively. In Group 2 (end-to-end repair without distraction), the elbow was externally fixed in hyperflexion and the nerve was repaired end-to-end. At fourteen days, the fixator was removed and unprotected elbow motion was permitted. In Group 3 (end-to-end repair with gradual distraction), the elbow was externally fixed in hyperflexion and primary neurorrhaphy was performed. At fourteen days, the elbow was extended 10° every other day with use of the articulated external fixator until full extension was achieved. Median nerve amplitude, latency, and nerve-conduction velocity; flexor digitorum superficialis single-twitch force generation and maximum tetanic force generation; muscle mass; and elbow range of motion were measured at three or six months. In addition, histologic analysis of the median nerve distal to the repair site and the morphometry of the neuromuscular junction in the flexor digitorum superficialis were performed at six months. Results: All rabbits regained full active and passive range of motion. At three months, the nerve-conduction velocities in Groups 2 and 3 were significantly greater than that in Group 1. At six months, the nerve-conduction velocities and amplitudes in Group 3 were significantly greater than those in Groups 1 and 2. At six months, the tetanic force in Group 3 was significantly greater than those in Groups 1 and 2. There were no significant differences in muscle mass among the groups. There were no significant differences in histological findings among the three groups, although there was a trend toward larger fiber size in Group 3 as compared with the other two groups. The neuromuscular junctions in Group 3 had a significantly larger surface area than did those in Group 1 (p = 0.002) and Group 2 (p = 0.034). Conclusion: The use of an articulated external fixator and controlled gradual distraction appears to facilitate the treatment of peripheral nerve defects. Clinical Relevance: This nerve repair technique may prove useful in clinical situations involving peripheral nerve defects. [ABSTRACT FROM AUTHOR]

Case: The lateral ulnar collateral ligament (LUCL) is one of the primary stabilizers of the elbow. Disruption typically occurs from the humeral origin and may be because of an elbow dislocation or fracture/dislocation. If not identified and properly managed, posterolateral rotatory instability may result from LUCL insufficiency. We describe the case of a patient with bipolar LUCL disruption consisting of an avulsion fracture of the crista supinatoris and a soft-tissue avulsion from the lateral epicondyle. Conclusion: Bipolar disruption of the LUCL is a previously unreported injury pattern that may lead to posterolateral instability if not identified and treated. [ABSTRACT FROM AUTHOR]

Introduction: Heterotopic ossification (HO) is a well-known sequela after an elbow injury and is widely studied given the associated morbidity. The anatomic location of HO development for specific elbow injuries has not been reported. The purpose of this study was to describe the precise, anatomic location of HO development after different peri-articular elbow injuries. Methods: A retrospective chart review was performed for patients with peri-articular elbow fracture and/or dislocation who underwent an elbow contracture release. The injuries were grouped into coronal shear distal humerus/AO 13.B3 (CSDH), distal humerus/AO 13.A, 13.B1, B2 or 13.C (DH), olecranon/AO 21.B1 (OL), radial head/AO 21.B2 (RH), extra-articular proximal radius and ulna/AO 21.A (EAPRU) fractures and elbow dislocations (DL). The HO location was determined by reviewing elbow radiographs and CT scans and were classified as anterior capsule, medial or lateral collateral ligaments, and posterior capsule/triceps insertion. Results: The study consisted of 49 patients, such as 6 CSDH, 13 DH, 6 OL, 21 RH, 4 EAPRU fractures and 20 elbow DL. All CSDH and RH fractures and 19/20 elbow DL developed HO in the collateral ligaments, while 12/13 DH fractures developed an anterior capsule HO. All 6 OL fractures developed HO posteriorly, and 3/4 EAPRU fractures developed a proximal radioulnar synostosis. Conclusions: Our findings suggest that the location of HO development is specific to the injury type and is influenced by the soft tissues involved. This is consistent with the understanding that HO is the abnormal ossification of normal structures. [ABSTRACT FROM AUTHOR]

Background: Longitudinal instability of the forearm (the Essex-Lopresti lesion) following radial head excision may be difficult to detect. This cadaveric study examines a stress test that can be performed in the operating room to identify injury to the ligamentous structures of the forearm.Methods: Twelve cadaveric upper extremities were randomized into two groups and underwent radial head resection. Group 1 underwent sequential transection of the triangular fibrocartilage complex and the interosseous membrane. Group 2 underwent sequential transection of the interosseous membrane and the triangular fibrocartilage complex. Ulnar variance and radial migration were examined with use of fluoroscopy of the wrist before, during, and after the application of a 9.1-kg load via longitudinal traction on the proximal part of the radius.Results: Group 1 demonstrated no significant changes in proximal radial migration with load (compared with the findings after radial head resection alone) after transection of the triangular fibrocartilage complex. However, Group 2 demonstrated significant changes in proximal radial migration with load after transection of the interosseous membrane (p = 0.03; median, 3.5 mm). In both groups, transection of both the triangular fibrocartilage complex and the interosseous membrane resulted in significant changes in proximal radial migration with load (p = 0.001; median, 9.5 mm). When the load was removed, specimens were ulnar positive (median, 3.0 mm), with no specimen returning to the preload position of ulnar variance (p = 0.001).Conclusion: After radial head resection, 3 mm of proximal radial migration with longitudinal traction indicated disruption of the interosseous membrane. In all specimens, proximal radial migration of > or =6 mm with load indicated gross longitudinal instability with disruption of all ligamentous structures of the forearm. [ABSTRACT FROM AUTHOR]