Shoulder proprioception following reverse total shoulder arthroplasty

Joint replacement affects the proprioception, as shown in knees, elbows, and shoulder studies. Aim The aim was to evaluate shoulder joint position sense (JPS) following reverse total shoulder arthroplasty (rTSA) for patients with cuff arthropathy. Methods Twenty-nine patients that underwent unilateral rTSA (19 females, 10 males) and 31 healthy volunteers evaluated for JPS of shoulder using a dedicated high accuracy electronic goniometer. Error of active reproduction of joint position (EARJP) was assessed at the following reference positions: 30 degrees, 60 degrees, 90 degrees, and 120 degrees for forward flexion and abduction and 15 degrees, 30 degrees, and 45 degrees for internal and external rotation in rTSA, contralateral non-operated, and control shoulders. Results Results of EPRJP for rTSA, contralateral, and control (respectively) are as follows:Forward flexion: 30 degrees = (8.0 +/- 5.7, 9.8 +/- 6.1, and 4.9 +/- 3.0), 60 degrees = (5.0 +/- 2.8, 5.9 +/- 2.7, and 5.1 +/- 3.2), 90 degrees = (3.1 +/- 1.6, 5.5 +/- 2.6, and 3.2 +/- 1.4), and 120 degrees = (3.4 +/- 2.1, 5.6 +/- 4.0, and 3.5 +/- 1.7)Abduction: 30 degrees = (5.2 +/- 2.5, 9.1 +/- 6.1, and 4.6 +/- 2.3), 60 degrees = (5.2 +/- 3.6, 6.6 +/- 4.1, and 5.3 +/- 3.1), 90 degrees = (3.8 +/- 2.0; 7.4 +/- 5.5, and 4.1 +/- 1.9), and 120 degrees = (5.3 +/- 2.9, 7.7 +/- 5.3, and 4.2 +/- 1.9)Internal rotation: 15 degrees = (4.3 +/- 3.1, 6.2 +/- 4.4, and 2.8 +/- 1.2), 30 degrees = (3.2 +/- 1.9, 4.5 +/- 2.3, and 3.3 +/- 1.4), and 45 degrees = (3.5 +/- 2.0, 4.1 +/- 1.8, and 2.8 +/- 1.0)External rotation: 15 degrees = (3.0 +/- 1.7, 4.2 +/- 2.2, and 3.6 +/- 1.4) and 30 degrees = (3.1 +/- 1.5, 3.8 +/- 2.6, and 3.4 +/- 1.6)The results showed significantly better JPS (lower EPRJP) in shoulders following rTSA and normal control shoulders comparing with the patient's contralateral shoulder. The explanation can be that rTSA improves joint kinematics and stability, which allows better muscular performance and proprioception feedback. Conclusion Shoulders following rTSA show JPS superior to non-operated contralateral shoulders and comparable with healthy population shoulders. It seems that rTSA restores shoulder proprioception.