ABSTRACT
BACKGROUND: Reversed shoulder arthroplasty (RSA) aims to restore function in patients with rotator cuff failure and joint arthropathy. After surgery, patients are routinely referred to a rehabilitation specialist to regain range of motion, strength, and function. A key element in these programs is active exercises. The exercises are often selected based on assumed muscle activity, investigated by electromyography (EMG). In particular, in this patient population, activation of the deltoid and the scapular muscles is the focus of exercise therapy. Currently, most studies investigating muscle activity levels during exercises are performed on healthy individuals. To our knowledge, no study exists analyzing EMG activity during exercises in a population of shoulder arthroplasty patients. Therefore, the study aimed to analyze activity in the shoulder girdle muscles during 6 commonly used rehabilitation exercises 12 weeks after RSA surgery. METHODS: Forty-four patients (50 shoulders) participated in this cross-sectional study, 12 weeks postoperatively (mean 99.18±12.8 days), aged 68.9±7.75 years. Surface EMG activity was measured in 10 shoulder girdle muscles: the 3 trapezius parts, serratus anterior, the 3 deltoid parts, latissimus dorsi, and 2 pectoralis major parts during 6 exercises, 3 in a closed chain, and 3 open chain elevation exercises. RESULTS: Gravity- minimized exercises (horizontal plane) show low activity for almost all muscles. Vertical closed kinetic chain exercises show an increased activity compared to horizontal plane exercises. Open kinetic chain exercises against gravity showed the greatest activity in Deltoid and Upper trapezius. For the other muscles no consistency in progression was found. CONCLUSION: This study offers a progression of exercises for patients after reversed shoulder arthroplasty based on increased muscle activity.
ABSTRACT
BACKGROUND: Glenoid component loosening remains an important concern in anatomic total shoulder arthroplasty. The aim of this study was to evaluate the clinical and radiographic results of a fully uncemented all-polyethylene fluted central peg bone-ingrowth glenoid component at a minimum 5-year follow-up. METHODS: Thirty-five shoulders in 31 patients (mean age, 73 years) with a mean follow-up of 100 months were retrospectively evaluated at an early and mid-term time point for Constant score (CS). Computed tomography visualized glenoid component fixation at both time points. RESULTS: Mean CS improved from 40 preoperatively to 66 postoperatively at latest follow-up (P < .001). A mean CS of 74 at early follow-up remained consistent with a mean CS of 66 at latest follow-up (P = .158), with only strength demonstrating a decrease over time (P < .001). An initial osseointegration rate of 81% at early follow-up decreased to 71% at latest follow-up with 74% of the shoulders demonstrating progressive radiolucent lines, resulting in a radiographic loosening rate of 31%. Of the 35 shoulders, 4 were revised (survival rate of 88%), of which 2 due to symptomatic aseptic loosening. CONCLUSIONS: Uncemented fixation of an all-polyethylene central peg bone-ingrowth glenoid was associated with satisfactory clinical and radiographic scores, and an acceptable revision rate at mid- to long-term follow-up. Despite initial bony osseointegration in the majority of cases, radiographic loosening over time remains a concern, potentially jeopardizing long-lasting fixation of this type of glenoid component when implanted in an off-label uncemented fashion.
