Anatomic total shoulder arthroplasty for patients with preserved preoperative motion

Abstract

BackgroundFor patients with end-stage glenohumeral osteoarthritis, anatomic total shoulder arthroplasty (TSA) serves as a reliable option for pain relief and improving function. It is not well understood if patients with pain due to osteoarthritis but preserved preoperative active range of motion (ROM) experience a similar postoperative benefit compared with those with more pronounced preoperative ROM deficits. MethodsA multicenter shoulder arthroplasty registry was queried to identify all patients who underwent TSA with minimum 2-year clinical follow-up. These patients were separated into two cohorts: (1) preserved preoperative active motion, defined as both forward flexion (FF) and external rotation (ER) at the side a minimum of one standard deviation greater than the mean (>140° FF and >45° ER), and (2) a control group with restrictions in preoperative motion, defined by both preoperative FF < 140° and ER < 45°. Controls were matched 2:1 to study patients by preoperative visual analog pain scale ± 1.5 points, sex, and age ± 2 years. Outcome measures were patient-reported outcomes, active ROM, and strength and satisfaction at a minimum of 2 years postoperatively. ResultsThirty patients were identified in the preserved preoperative motion group (mean baseline 154 ± 10° FF and 57 ± 11° ER). Sixty control patients with restricted motion were matched (mean baseline 97 ± 24° FF and 23 ± 16° ER). There were no significant differences in other baseline patient characteristics other than the Constant-Murley score and strength. At 2-year follow-up, there were no significant differences in visual analog pain scale (0.8 vs. 1.1, P = .446), all patient-reported outcomes, or any ROM measures other than FF which was higher in the preserved group (158 ± 15° vs. 146 ± 19°, P = .003). The change in ROM was significantly higher for all ROM measurements in the restricted motion cohort with restricted preoperative motion compared with study patients. Patients with restricted motion had a significantly greater increase in Constant scores than those with preserved motion (32.6 vs. 19.0, P < .001). There were no significant differences in rates of patients who were satisfied with their surgical result for all domains assessed between groups. ConclusionPatients undergoing TSA with preserved preoperative active ROM can expect similar final pain levels and improvement in pain compared with patients with greater limitations in preoperative ROM. As expected, patients with more restricted preoperative ROM have substantially greater improvement in ROM after TSA. However, there are no differences in satisfaction at 2 years after TSA regardless of preoperative active ROM. Level of evidenceLevel III; Retrospective Cohort Comparison; Treatment Study