Mechatronic Design of a Prototype Orthosis to Support Elbow Joint Rehabilitation

Comparative study of open elbow arthrolysis with and without hinge external fixation for the treatment of post-traumatic elbow stiffness

BACKGROUND

The present study aimed to compare the functional outcomes of hinged external fixators and non-external fixation in open elbow arthrolysis (OEA) for post-traumatic elbow stiffness (PTES) and to evaluate their applicability and limitations in patients with posttraumatic elbow stiffness.

METHODS

The clinical data of patients with PTES treated with OEA at our hospital between March 2015 and June 2022 were retrospectively analyzed. The assessed variables were the operation time, intraoperative blood loss volume, duration of hospitalization, and treatment costs. The elbow range of motion (ROM), Mayo Elbow Performance Score (MEPS), shortened disabilities of the arm, shoulder and hand questionnaire (Q-DASH) score, Oxford Elbow score (OES), Broberg and Morrey score (BMS), visual analog scale (VAS) for pain, and complications such as pin tract infection and heterotopic ossification were compared between patients with and without hinge external fixation. We also compared the baseline characteristics and functional outcomes of patients with and without hinge external fixation.

RESULTS

A total of 156 patients (48 patients with hinged external fixators and 108 patients without external fixators) diagnosed with PTES were included in this study. The mean follow-up was 15.8 ± 3.6 months. Compared with patients without external fixators, those with external fixators showed significantly greater improvements in elbow flexion and extension ROM (59.6° ± 26.1° vs. 46.2° ± 26.2°, p = 0.004) but had a significantly longer duration of hospitalization (p < 0.001), significantly longer operation time (p < 0.001), significantly higher treatment costs (p < 0.001), and significantly greater intraoperative blood loss volume (p < 0.001). There were no significant differences between the two groups in terms of improvement in elbow rotation ROM, MEPS score, VAS score for pain, OES score, Q-DASH score, BMS score, or incidence of complications.

CONCLUSION

The use of a hinged external fixator in open arthrolysis for posttraumatic elbow stiffness may result in short-term improvements in flexion-extension range of motion but is accompanied by increased blood loss, longer operative time, extended hospitalization, and higher costs. Further studies are needed to confirm these findings.

CLINICAL TRIAL NUMBER

Not applicable.

Biomechanical study of the effect of traction on elbow joint capsule contracture

Dynamic orthoses have a significant effect on the treatment of elbow capsular contracture. Because of the lack of quantitative research on traction forces, determining the appropriate traction force to help stretch soft tissues and maintain the joint's range of motion is a challenge in the rehabilitation process. We developed a human elbow finite element (FE) model incorporating the activity behavior of the muscles and considering different capsular contracture locations, including total, anterior and posterior capsular contractures, to analyze the internal biomechanical responses of different capsular contracture models during flexion (30 to 80 degrees). Traction loads of 10, 20, 30 and 40 N were applied to the ulna and radius at the maximum flexion angle (80 degrees) to explore the appropriate traction loads at week 4 after a joint capsule injury. We observed a significant increase in posterior capsule stress with anterior capsular contracture (ACC), and the maximum peak stress was 1.3 times higher than that in the healthy model. During the fourth week after elbow capsule injury, the appropriate traction forces for total capsule contracture (TCC), ACC and posterior capsule contracture (PCC) were 20, 10 and 20 N, respectively; these forces maintained a stable biomechanical environment for the elbow joint and achieved a soft tissue pulling effect, thus increasing elbow mobility. The results can be used as a quantitative guide for the rehabilitation physicians to determine the traction load for a specific patient.