Elbow Kinematics and Function Following Treatment with Open Arthrolysis and Hinged External Fixator.

Abstract

Open arthrolysis (OA) combined with hinged external fixator (HEF) is a promising surgical option for patients with elbow stiffness. This study aimed to investigate elbow kinematics and function following a combined treatment with OA and HEF in elbow stiffness cases. Patients treated with OA with or without HEF due to elbow stiffness were recruited between August 2017 and July 2019. Elbow flexion-extension motion and function (Mayo elbow performance scores, MEPS) were recorded and compared between patients with and without HEF during a 1-year follow-up period. Additionally, those with HEF were assessed by dual fluoroscopy at week 6 postoperatively. Flexion-extension and varus-valgus motions, as well as ligament insertion distances of the anterior medial collateral ligament (AMCL) and lateral ulnar collateral ligament (LUCL), were compared between the surgical and intact sides. This study included 42 patients, of which 12 with HEF demonstrated a similar flexion-extension angle and range of motion (ROM) and MEPS as the other patients. In patients with HEF, the surgical elbows showed limitations in flexion-extension (maximal flexion, 120.5° ± 5.3° vs 140.4° ± 6.8°; maximal extension, 13.1° ± 6.0° vs 6.4° ± 3.0°; ROM, 107.4° ± 9.9° vs 134.0° ± 6.8°; all Ps < 0.01) compared with the contralateral sides. During elbow flexion, a gradual valgus-to-varus transition of the ulna, increase in the AMCL insertion distance, and steady change in the LUCL insertion distance were observed, with no significant differences between the bilateral sides. Patients treated with OA and HEF demonstrated similar elbow flexion-extension motion and function to those treated with OA alone. Although the use of HEF could not restore an intact flexion-extension ROM and might result in some minor but not significant changes in kinematics, it contributed to clinical outcomes comparable to that of the treatment with OA alone.