Is malunion of the greater tuberosity after reverse shoulder arthroplasty in patients with complex proximal humerus fracture associated with worse clinical outcomes? A prospective cohort study

PURPOSE

To assess patient outcomes following reverse shoulder arthroplasty in patients with complex proximal humerus fracture and the clinical implications of greater tuberosity malunions.

METHODS

This prospective study included 56 patients who underwent RSA (DELTA XTEND™, DePuy Synthes, Warsaw, IN, USA) to treat proximal humerus fractures. We used a standardized suture technique to reattach the tuberosities. Demographic, comorbidity, and radiological parameters were collected. Assessments at 2-year follow-up (n = 49) are given as follows: range of motion (ROM), pain level, Constant Murley scores (CS), subjective shoulder value (SSV), and tuberosity healing.

RESULTS

Anatomic tuberosity healing was achieved in 31 (55%) patients (group 1), 14 (25%) had a malunion (group 2), and complete migration occurred in 11 (20%) (group 3). No statistically significant differences between groups 1 and 2 were detected: CS (p = 0.53), SSV (p = 0.07), ROM (forward flexion (FF) p = 0.19, internal rotation (IR) p = 0.34, and external rotation (ER) p = 0.76). Group 3 had poorer outcomes (median [IQR]) than group 1: CS (59 [50-71]) vs. 72 [65-78]), FF (120 [100-150]) vs. 150 [125-160] and ER (- 20 [- 20 to 10] vs. 30 [20-45], respectively. Three complications (group 1) occurred: one-stage revision after low-grade infection, haematoma due to early rivaroxaban intake, and open reduction and internal fixation for acromion insufficiency fracture. No patients showed signs of stem or glenoid loosening after 2 years.

CONCLUSION

Cases with complete superior migration experienced poorer clinical outcomes than those with anatomic healing. Despite a relatively high malunion rate, the outcomes were not significantly worse in these patients compared to anatomically healed GT cases.

[Current trends in reverse fracture arthroplasty]

The reliable results of reverse arthroplasty have made this the preferred treatment method for non-reconstructable proximal humeral fractures. The individual consideration of the patient and the morphological features of the fractures are essential. Computed tomography (CT) images provide crucial information on the perfusion of the humeral head relevant for the prognosis and treatment. In this context a differentiation must be made between hard and soft criteria against a reconstruction. Tuberosities should be reduced whenever possible, because reverse arthroplasty with healed tuberosities provides a better range of motion and more strength for external rotation and anteversion, less complications and longer survival rates. In recent years the trend has been towards anatomical designs of prostheses with a humeral inclination of 135°. Revision rates for primary fracture prostheses are overall low with instability as the main reason for revision surgery, followed by periprosthetic fractures and infections. Reverse fracture arthroplasty has comparable or better clinical results compared to conservative treatment, osteosynthesis for geriatric patients, hemiarthroplasty and prosthesis implantation by elective surgery. Reverse arthroplasties, which were implanted in conditions of fracture sequelae, did not achieve significantly poorer clinical outcome at mid-term follow-up and can significantly improve shoulder function.

Tuberosity union in patients with proximal humerus fractures treated with reverse shoulder arthroplasty: a technical note and exploratory analysis

PURPOSE

The use of reverse shoulder arthroplasty (RSA) to treat complex humerus fractures is increasing, especially in older, osteoporotic patients. Refixation and tuberosity healing are needed to achieve an optimal range of motion (ROM), external rotation, active forward elevation, and patient satisfaction. Proper healing has been reported, however, in only 40-84% of cases. Our study's aim was to describe a simple, reproducible fixation technique designed to improve tuberosity healing.

METHODS

We included 30 patients with acute proximal humerus fractures undergoing RSA (Global Unite Reverse Fracture, DePuy Synthes, Warsaw, IN, USA) with tuberosity reattachment. The humerus stem was cemented in 24 cases. A standardized suture technique with two fiber tapes was used to reattach tuberosities. Clinical and radiological parameters, which were collected one year post-operatively, included ROM, pain level, Constant scores, subjective shoulder value (SSV), and tuberosity healing.

RESULTS

The mean age of the patients was 79.3 years (± 7; range 65-92), and the tuberosity healing rate was 90.0% (27 of 30). Two patients showed migration (one nonunion, one malunion), and another had complete resorption after an initial period of proper healing. Radiolucent lines around the humerus stem occurred in one case, and three patients had scapular notching. The mean SSV was 86% (± 11; range 60-100), the Constant score was 72 (± 10.3; range 48-92), the active forward flexion was 140° (± 14.3; range 115-165), and external rotation was 23° (± 16.5; range 0-50).

CONCLUSIONS

This reattachment technique, which is simple and reproducible, achieved a higher tuberosity healing rate than previously published rates.