Continuous Shoulder Activity Tracking after Open Reduction and Internal Fixation of Proximal Humerus Fractures

Postoperative shoulder activity after proximal humerus fracture treatment could influence the outcomes of osteosynthesis and may depend on the rehabilitation protocol. This multi-centric prospective study aimed at evaluating the feasibility of continuous shoulder activity monitoring over the first six postoperative weeks, investigating potential differences between two different rehabilitation protocols. Shoulder activity was assessed with pairs of accelerometer-based trackers during the first six postoperative weeks in thirteen elderly patients having a complex proximal humerus fracture treated with a locking plate. Shoulder angles and elevation events were evaluated over time and compared between the two centers utilizing different standard rehabilitation protocols. The overall mean shoulder angle ranged from 11° to 23°, and the number of daily elevation events was between 547 and 5756. Average angles showed longitudinal change <5° over 31 ± 10 days. The number of events increased by 300% on average. Results of the two clinics exhibited no characteristic differences for shoulder angle, but the number of events increased only for the site utilizing immediate mobilization. In addition to considerable inter-patient variation, not the mean shoulder angle but the number of elevations events increased markedly over time. Differences between the two sites in number of daily events may be associated with the different rehabilitation protocols.

Quantifying shoulder activity after rotator cuff repair: Technique and preliminary results

Repair tissue healing after rotator cuff repair remains a significant clinical problem, and excessive shoulder activity after surgical repair is believed to contribute to re-tears. In contrast, small animal studies have demonstrated that complete removal of activity impairs tendon healing and have advocated for an "appropriate" level of activity, but in humans the appropriate amount of shoulder activity to enhance healing is not known. As an initial step toward understanding the relationship between postoperative shoulder activity and repair tissue healing, the objectives of this study were to assess the precision, accuracy, and feasibility of a wrist-worn triaxial accelerometer for measuring shoulder activity. Following assessments of precision (±0.002 g) and accuracy (±0.006 g), feasibility was assessed by measuring 1 week of shoulder activity in 14 rotator cuff repair patients and 8 control subjects. Shoulder activity was reported in terms of volume (mean acceleration, activity count, mean activity index, active time) and intensity (intensity gradient). Patients had significantly less volume (p ≤ .03) and intensity (p = .01) than controls. Time post-surgery was significantly associated with the volume (p ≤ .05 for mean acceleration, activity count, and mean activity index) and intensity (p = .03) of shoulder activity, but not active time (p = .08). These findings indicate this approach has the accuracy and precision necessary to continuously monitor shoulder activity with a wrist-worn sensor. The preliminary data demonstrate the ability to discriminate between healthy control subjects and patients recovering from rotator cuff repair and provide support for using a wearable sensor to monitor changes over time in shoulder activity.

Retears and Concomitant Functional Impairments After Rotator Cuff Repair: Shoulder Activity as a Risk Factor

BACKGROUND

Most patients return successfully to shoulder involving sports or activity after rotator cuff repairs. It has not been decided yet whether postoperative participation in shoulder activity adds to the risk of retear.

PURPOSE/HYPOTHESIS

The purpose was to verify whether patients who participate in shoulder activities after rotator cuff repair have a higher risk of structural failure than nonactive patients and to investigate the relationship between postoperative shoulder function and tendon integrity in active and nonactive patients. The hypotheses were that (1) active patients have a higher retear rate than nonactive patients and (2) structural failure is associated with worse functional outcomes in active patients.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A cohort study was performed using 145 patients who underwent arthroscopic rotator cuff repair from 2015 to 2017. Functional assessments and magnetic resonance imaging were performed at least 24 months postoperatively. Shoulder activities since 6 months after surgery were rated in 4 categories (sports, job, activities of daily life, and weight of general lifting) as sedentary, light, moderate, or strenuous. The activity level of each patient was defined by the highest rated category. Patients who were involved in light, moderate, and strenuous activity were identified as active for the present study, and the rest were defined as sedentary. The proportion of retears between groups and the functional conditions between retorn and intact tendons were compared.

RESULTS

A total of 48 patients were enrolled in the active group, and 97 were enrolled in the sedentary group. The active group demonstrated a significantly higher retear rate than the sedentary group (27.1% vs 11.3%, respectively; P = .016; risk ratio, 2.39 [95% CI, 1.16-4.93]). In the active group, patients with retears showed higher visual analog scale scores for pain, decreased abduction strength, and lower shoulder functional scores (American Shoulder and Elbow Surgeons score, Fudan University Shoulder Score, and Constant-Murley score) than those with healed tendons, whereas in the sedentary group, functional outcomes were generally similar across patients with and without retears.

CONCLUSION

Shoulder activity after the early postoperative period was associated with a high risk of retears in patients who underwent rotator cuff repair. A correlation between inhibited function and structural failure was detected but only in active patients, while sedentary patients with retears retained functional improvements similar to those with intact tendons.