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Background: Previous work evaluating the pronator quadratus (PQ) muscle following volar plate fixation (VPF) of distal radius fractures (DRF) suggests that PQ repair often fails in the postoperative period. The purpose of this investigation was to assess PQ repair integrity following VPF of DRF using dynamic musculoskeletal ultrasonography. Methods: Twenty adult patients who underwent VPF of DRF with repair of the PQ with a minimum follow-up of 3 months underwent bilateral dynamic wrist ultrasonography. The integrity of the PQ repair, wrist range of motion (ROM) and strength, and functional outcome scores were assessed. Results: Mean patient age at the time of surgery was 59 ± 14 years, and 50% underwent VPF of their dominant wrist. Patients were evaluated at a mean 9 ± 4 months after VPF. All patients had an intact PQ repair. The volar plate was completely covered by the PQ in 55% of patients and was associated with a larger PQ when compared to patients with an incompletely covered volar plate ( P = .026). The flexor pollicis longus tendon was in contact with the volar plate in 20% of patients, with those patients demonstrating a trend toward significantly increased wrist flexion ( P = .053). No difference in ROM, strength, or outcome scores was noted among wrists with completely or incompletely covered volar plates. Conclusions: The PQ demonstrates substantial durability after repair following VPF. Wrist ROM, strength, and functional outcomes are similar in wrists in which the volar plate is completely or incompletely covered by the repaired PQ.

Background: Forearm immobilization techniques are commonly used to manage distal radius, scaphoid, and metacarpal fractures. The purpose of our study was to compare the degree of rotational immobilization provided by a sugar-tong splint (STS), short arm cast (SAC), Munster cast (MC), and long arm cast (LAC) at the level of the distal radioulnar joint (DRUJ), carpus, and metacarpals., Methods: Seven cadaveric upper extremity specimens were mounted to a custom jig with the ulnohumeral joint fixated in 90° of flexion. Supination and pronation were unrestricted. K-wires were placed in the distal radius, scaphoid, and metacarpals using fluoroscopic guidance to measure the total arc of rotation referenced to the ulnar ex-fix pin. Baseline measurements followed by sequential immobilization with well-molded STS, SAC, MC, and LAC were obtained with 1.25, 2.5, and 3.75 ft-lb of supination and pronation force directed through the metacarpal K-wire. Each condition was tested 3 times. Digital photographs were taken perpendicular to the ulnar axis to analyze the total arc of motion., Results: The most effective constructs from least to greatest allowed rotational arcs were LAC, MC, SAC, and STS. Above-elbow constructs (MC, LAC) demonstrated superior immobilization compared with below-elbow constructs (SAC) ( P < .001). Circumferential constructs (SAC, MC, LAC) were superior to the noncircumferential construct (STS) ( P < .001). There were no significant differences between the MC and LAC in all conditions tested., Conclusions: Both circumferential and proximally extended immobilization independently improved rotational control of the wrist. However, extending immobilization proximal to the epicondyles did not confer additional stability.