The effect of scapholunate dissociation on wrist function in patients with distal radius fractures

Purpose This study aimed to investigate the effect of scapholunate dissociation (SLD) on wrist function after distal radius fractures (DRFs). Methods This retrospective study was conducted to analyze the clinical information of 96 patients diagnosed with unilateral DRFs who received open reduction and internal fixation (ORIF) from October 2019 to September 2023. Mean follow-up was 17.9±4.2 (range, 12–24) months. Patients were divided into three groups: group1 (SLI＜2mm, n＝52), group2 (2mm≤SLI＜3mm, n=32), and group3 (SLI≥3mm, n=12) according to the scapholunate interval (SLI) on the central coronal slice of the computed tomography (CT) scan. The SLI was measured at the distal end of the scapholunate joint on the central coronal slice of the CT scan. Demographic features of patients, the scapholunate angle (SLA), and postoperative radiographic parameters (including volar tilt, ulnar inclination, and radial height), as well as functional outcomes related to wrist range of motion (ROM), pain (VAS), and function (DASH), were assessed and compared among the different groups. Results All patients underwent successful surgeries. No complications related to soft tissues, including incision, blood vessel, or nerve injuries, occurred during the operation, post-operation, or in the perioperative period. The average SLA was (54.3°±7.1°, 63.1°±4.6°, 72.9°±4.7°) in group1, group2, and group3, respectively. The SLA in group3 was larger than that in the other two groups (F = 62.801, P < 0.001). There was significant difference in the size of the SLA among the three groups (P < 0.05). There was no significant difference in postoperative radiographic parameters (including volar tilt, ulnar inclination, and radial height) among the three groups immediately after operation (P > 0.05). The ROM of wrist flexion of the three groups at 3 months after operation were (51.2°±5.5°,47.4°±3.6°, 45.3°±3.6°), the ROM of wrist extension were (49.1°±4.4°,45.5°±2.9°, 44.3°±2.6°), the VAS were (1.9±0.5, 2.2±0.4, 2.4±0.5), and the wrist DASH scores were （22.2±2.4 , 24.0±3.3, 25.7±3.6), respectively. The ROM of wrist flexion and extension, VAS and DASH scores in group1 were better than those in group2, and group3 (P < 0.05). There were no significant differences in terms of the ROM of wrist flexion and extension, VAS and DASH scores between group2 and group3 (P > 0.05). The ROM of wrist flexion of the three groups at 12 months after operation were (68.8°±4.3°,66.5°±4.3°, 65.3°±5.1°), the ROM of wrist extension were (65.5°±4.7°,64.2°±3.2°,61.6°±4.8°) and the wrist DASH scores were（12.7±2.2, 14.2±2.9, 15.1±3.1), respectively. The ROM of wrist flexion and extension, DASH scores in group 1, group 2 were better than those in group 3 (P < 0.05). There were no significant differences in terms of the ROM of wrist flexion and extension, and DASH scores between group1 and group2 (P > 0.05). Conclusion This study demonstrated that wrist function after surgery is notably restricted When the SLI ≥ 3.0mm. Consequently, additional interventions are required for patients with a SLI ≥ 3.0mm to enhance their wrist functionality.