Type 1 Complex Regional Pain Syndrome After Subacromial Shoulder Surgery: Incidence and Risk Factor Analysis

Complex Regional Pain Syndrome type 1 (CRPS1) is a potential complication, affecting the prognosis of functional joint recovery. Its incidence ranges from 2 to 40% depending on the series and the joints involved. Very few studies have evaluated the incidence of CRPS after shoulder surgery. The objective of our study was to determine the incidence of CRPS1 and to identify any pre-operative risk factors associated with its emergence after extra-articular subacromial space surgery.

This is a retrospective single-centre study of patients who underwent surgery for a subacromial extra-articular shoulder pathology from January 2016 to December 2016 and included a follow-up period of at least 6 months. The primary inclusion criterion was developing a CRPS1 as defined by Veldman. A pre- and post-operative clinical assessment was performed based on the Constant (Cst) score.

Among the 287 patients, with an average follow-up period of 6.5 months, included in the study, 38 (13%) presented with post-operative CRPS1. Treated hypothyroidism (OR = 3.79; 95% CI 1.58;9.07; p = 0.003), open surgery (OR = 2.92; 95% CI 1.35-6.32; p = 0.007) and the level of daily physical activity from the Cst score (OR = 0.088; 95% CI 0.79;0.97; p = 0.015) were found to be significantly associated with the onset of CRPS1.

CRPS1 affected more than 10% of patients who underwent surgery for a subacromial shoulder pathology. The current study identified hypothyroidism, open surgery, and pre-operative clinical status as risk factors for the onset of this complication. These parameters should, therefore, be taken into consideration during the patient's pre-operative consultation.