Short to mid-term results of stemless reverse shoulder arthroplasty in a selected patient population compared to a matched control group with stem

Abstract

Purpose: Little scientific evidence on the clinical and radiological outcome after stemless reverse shoulder arthroplasty (RSA) exists. The hypothesis of this study was that stemless RSA has an inferior outcome compared to RSA with stem.

Methods: All cases of cuff-arthropathy fullfilling strict selection criteria (selection rate 18.4 %) were treated with stemless RSA between 2009 and 2013. Twenty nine of 37 cases (78.4 %) were clinically and radiologically examined by an independent observer. Twenty four of the 29 cases could be matched with 24 patients that underwent conventional stemmed RSA at a different institution based on the following criteria: indication (cuff-arthropathy), age (within 5 years), gender, and time of follow-up (within 2 years). Clincial and radiological outcomes of both groups were compared.

Results: After mean follow-up of 35 months (range 24-75) no significant difference regarding constant score, ASES, subjective shoulder value, pain score, patient satisfaction, strength, and range of motion was detected. One case of traumatic dislocation was observed in the stemless RSA group. Scapular notching grade 1 was detected in two cases of the stemless group while in the stemmed group five cases with grade 1 and four cases with grade 2 notching were observed. Average post-operative humeral component inclination (neck-shaft angle) in the stemless RSA group (134.4°) was significantly steeper than in the stemmed RSA group (155°) (p < 0.001). No loosening of the humeral component was observed in both groups.

Conclusion: At short to mid-term follow-up, stemless RSA does not feature inferior clinical or radiological outcomes in a strictly selected patient population.

Keywords: Inclination; Neck-shaft angle; Notching; RSA; Reverse shoulder arthroplasty; Stemless.