Rotator cuff tears are common and 250,000 to 300,000 rotator cuff repairs (RCR) are performed in the United States every year, with an increasing percentage of them being carried out arthroscopically [1, 2]. The functional outcomes of RCR are reportedly affected by several parameters, including fear-avoidance behavior, alcohol consumption, sex, workers compensation claims, previous RCR procedure, preoperative functional score of the involved or the contralateral shoulder, smoking status, age, activities of daily living, subacromial decompression, tear size, biceps tendon intervention, preoperative pain, and muscle atrophy [3,4,5].

Fibromyalgia is described as a centralized pain state that is prevalent in 2–8% of the population, and characterized by widespread pain often accompanied by fatigue, memory problems, and sleep disturbances [6]. The effect of fibromyalgia on the outcomes of orthopedic surgery has been studied and reported in several publications. A recent systematic review described it as a risk factor for poor outcomes following orthopedic surgery [7]. Specific to shoulder surgery, another recent systematic review stated that due to the scarcity and low level of evidence in the available literature, it is currently impossible to determine whether fibromyalgia does or does not have an effect on shoulder surgery outcomes [8].

The aim of our study was to compare the outcomes of patients with and those without fibromyalgia who underwent arthroscopic rotator cuff repair (ARCR) in one medical institution, and to determine whether ARCR outcomes are affected by fibromyalgia. We hoped to provide clinical evidence of the effect of fibromyalgia on the outcome of surgery for rotator cuff tears to shoulder surgeons who treat patients with these coexisting pathologies.