Patient-Reported and Objectively Measured Function before and after Reverse Shoulder Arthroplasty

Background and Purpose: Documenting functional outcomes after reverse shoulder arthroplasty (RSA) is critical to advancing patient care. The interplay been self-reported and objectively measured outcome measures has not been widely described. The utilization of wearable devices to document upper extremity limb activity is a new approach for objectively measuring outcomes. Therefore, the purpose of this study was to evaluate changes in pain, and self-reported function and objectively measured limb activity after RSA. We also assessed the influence of pain on self-reported function and objectively measured limb activity to determine the impact of pain on outcomes after RSA. Materials: This study implemented a prospective, repeated-measures design. Fourteen patients undergoing RSA underwent testing before surgery, and 2 and 12 months after surgery. Patient-reported instruments included pain, Disabilities of Arm, Shoulder and hands (DASH), and physical component summary (PCS) of the 36-Item Short Form Health Survey. Objective limb activity (mean activity value, m/s²/min epoch; inactive time, %; low activity, %; and high activity, %) was captured with triaxial accelerometers worn on the upper and lower arm. A repeated-measures ANOVA tested for differences across time. The Spearman rank-order correlation was calculated to evaluate the influence of pain on DASH, PCS scores, and mean limb activity. Results: Patient-reported measures improved after surgery (pain, P <.01; DASH, P <.01; PCS, P =.01). No change in limb activity was found at 1 year compared with preoperative values for mean (forearm, P = 1.00; arm, P =.36), inactivity (forearm, P =.33; arm, P =.22), low (forearm, P =.77; arm, P =.11) or high (forearm, P = 1.00; arm, P =.20) activity. There was a relationship between pain and DASH scores 1 year after surgery (P =.04) but not before surgery (P =.16), or 2 months after surgery (P =.30). There was no relationship between pain and PCS scores at any time point (preoperative, P =.97; 2 months, P =.21; 1 year, P =.08) nor pain and limb activity (forearm: preoperative, P =.36; 2 months, P =.67; 1 year, P =.16; arm: preoperative, P =.97; 2 months, P =.59; 1 year, P =.51). Conclusions: RSA reduced pain and enhanced patient-perceived function. Objectively measured upper extremity limb activity is not different 1 year after surgery compared with preoperative levels. Level of Evidence: III.