Summary

Distance of 45 mm from acromion tip to the greater tuberosity demonstrated the best outcomes in terms of the range of motion, pain score and function post reverse shoulder arthroplasty for rotator cuff arthropathy

Abstract

Background

Rotator cuff arthropathy is a debilitating condition that causes pain and loss of function. Reverse shoulder arthroplasty (RSA) is an established treatment modality for this condition and can provide pain relief and restoration of function. In the absence of a rotator cuff, it restores the function of the shoulder by medializing the glenohumeral centre and leveraging on the deltoid muscle. Suitable tensioning of the deltoid is vital in ensuring the success of an RSA procedure.

Questions/Purposes
In this study we aim to identify the ideal RSA position in correlation to deltoid length, by utilizing Acromial Greater Trochanteric distance as a marker and assessing how its variation affects functional outcomes.

Patients and Methods
We retrospectively reviewed the prospectively collected perioperative data of 61 patients who underwent RSA. All 61 patients were assessed peri-operatively according to the 100-point modified Constant-Murley shoulder score, Visual Analogue Score, Oxford shoulder score and the University of California Shoulder Score. Post-operative assessment was performed at six-month and one-year time points. 2 independent observers measured the acromion to greater trochanter distance from the postoperative plain radiographs.

Results

The mean age of our patients was 69.9 ± 8.3. All patients demonstrated significant improvement in range of motion, pain score and function scores. A distance of 45 mm from acromion tip to the greater tuberosity demonstrated the best outcomes in terms of the range of motion, pain score and function. Lengths shorter than or greater to that demonstrated diminished outcomes.

Conclusion

We have demonstrated the ideal distance between the acromion and the greater tuberosity tip for the placement of an RSA. In this study we confirm that RSA is a reliable option for rotator cuff arthropathy in old patients with good results and for restoring shoulder functions. Future studies need to validate our findings with a larger sample size and longer duration of follow-up.