Radiological and functional 24-month outcomes of resurfacing versus stemmed anatomic total shoulder arthroplasty

This study compared clinical and radiographic outcomes of patients undergoing resurfacing total shoulder arthroplasty (TSA) with those treated with a stemmed TSA.

Patients with primary osteoarthritis who underwent humeral resurfacing (RES) or stemmed (STA) TSA were identified in our shoulder arthroplasty register for retrospective analysis. Standard radiographs and clinical/patient-rated assessments were made up to 24 months post-surgery. Implant revisions were assessed. Patients were frequency-matched in a 1:1 (RES:STA) ratio based on gender and age, and compared with regard to operation time and shoulder function (Constant, SPADI and Quick DASH scores). Mixed models with statistical adjustments were applied.

From 2006 to 2014, 44 RES and 137 STA operations were performed in 157 patients; one and two revisions were recorded in the RES and STA group, respectively. The final matched cohort included a total of 69 patients and 37 operations per treatment group. Resurfacing TSA was 17 min shorter (95%CI: 5-28) compared to the stemmed procedure (p = 0.005). RES and STA patients showed significant functional improvement six months post-implantation, yet all measured scores did not differ between the groups at 2 years (p ≥ 0.131). The status of static centering of the humeral head, acromiohumeral distance, and a lack of signs of implant loosening were also similar between treatments.

Similar 24-month post-operative radiological and functional outcome is achieved by RES and STA patients, even with a shorter RES surgery time. Larger cohorts and longer follow-up are required to better assess implant survival.