Treatment Effects of Reverse Total Shoulder Arthroplasty for Unilateral Cuff Tear Arthropathy – Outcomes at 6, 12, 24 and 60 Months and Confounders

Joerg Huber

Department of Orthopedics, Stadtspital Triemli, Switzerland

^*Correspondance to: Joerg Huber 

 PDF  Full Text DOI: 10.25107/2474-1647.2718

Abstract

Background: Although shoulder arthroplasty is less common than knee or hip arthroplasty, the number of procedures being performed is increasing rapidly. The aim of this study was to measure the treatment effects of reverse total shoulder arthroplasty for unilateral rotator cuff arthropathy in a multicenter study over 5 years and analyze the influence of different confounders (preoperative severity of degenerative shoulder pathology as Hamada grade, gender, age, dominant side and comorbidities) on the two-year outcome. Methods: The patients of five European clinics specialized in shoulder surgery in three countries were included in this prospective study. Each patient had reversed total shoulder arthroplasty (Affinis® inverse, Fa Mathys, Bettlach, Switzerland) in a standardized way in beach chair position with cementless fixation of the base plate of the glenoid component and non-cemented or cemented fixation of the stem. The outcome was measured as Treatment Effects (TE’s), a number to describe the outcome of each patient (positive = amelioration, 0= unchanged, negative = worse). The treatment effect can be calculated as follows: score reduction/score preop. 1 is the maximal effect and corresponds to a patient without symptoms/impairments. 0 means no effect and a negative TE means more symptoms/impairments than preoperatively. A prerequisite for correct calculation is a positive score, meaning 0 equals no symptoms/impairments and a positive number symptoms/ impairments. Therefore the used American Shoulder and Elbow Surgeons (ASES) score needed to be inversed. The primary aim was to calculate the TE’s for RSA at 6, 12, 24, and 60 months postoperatively. The secondary aim was to analyze different confounders (preoperative grade of cuff tear arthropathy, age, gender, dominance, side of the affected shoulder, general co-morbidities measured using ASA grade). Results: A 203 patients were included for this analysis of whom 183 patients had a complete followup ASES score. Over the 24-month follow-up period, the mean ASES score augmented significant from 20.5 to 78.7 (a difference of 58.2 (p<0.001)). The treatment effects two years postoperatively ranged from 1 to 0.09 (the maximum being 1). We had no patient with a negative TE. The median TE 24-month postoperatively was 0.76. In the adjusted linear regression model a higher Hamada grade was associated with better TE’s (Hamada grade 4+ vs. 2 differences in TE’s 0.08 95% confidence interval (CI) (0.00 to 0.15), p-value 0.042). For age and dominant side there were weak associations where those aged 80+ and dominant side had better TE’s. For gender there was no association. The patients with higher ASA grade had lower TE’s (ASA grade 4+ vs. 1 difference in TE’s -0.16 95% Confidence Interval (CI) (-0.03 to -0.28), p-value 0.013). The median TE’s for the different followup intervals were 0.77 at 6-months, 0.81 12-months, 0.76 24-months and 0.73 at 60-months. Conclusion: The treatment effects for reverse shoulder arthroplasty vary from 1 to 0.09. For correct calculation the ASES score had to be inversed. The treatment effects changed little in the first five postoperative years (varying from 0.73 to 0.81). The confounders for better TE’s in this cohort were: higher severity of cuff arthropathy (Hamada grade 3, 4 and 5), less co-morbidities (ASA Grade 1), higher age (80+) and dominant side. Gender did not influence the 2-year TE’s.

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Cite the article

Huber J. Treatment Effects of Reverse Total Shoulder Arthroplasty for Unilateral Cuff Tear Arthropathy – Outcomes at 6, 12, 24 and 60 Months and Confounders. Clin Surg. 2020; 5: 2718..