Isolated arthroscopic subacromial decompression (IASD) is a widely used surgical procedure with high success rates. However, up to 25% of patients experience residual pain. It is unclear whether aberrant central nervous system processing of pain as described in fibromyalgia (FM) could have a detrimental effect on outcomes. To test this hypothesis, the authors conducted a retrospective case- control study of patients undergoing IASD.
Between 2008 and 2015, 26 patients with preoperative diagnosis of fibromyalgia and an IASD procedure were identified. Six patients were lost to follow-up. Each fibromyalgia patient was matched with one control patient (n=20) recruited from the remainder with IASD. Outcomes were assessed by DASH score (Disability Arm Shoulder and Hand), Constant (CS), relative Constant score (rCS) and Visual Analogue Scale (VAS). Patient satisfaction was determined with a single 2-level question. Failure of the IASD was defined as persistent pain (VAS>3) at last follow-up.
The average age of the sample was FM/Control group 51/48, with a mean follow-up of 36/42 months respectively. Both groups exhibited significant clinical improvement in the pain VAS, DASH and rCS at final follow-up (P<.001) compared with the preoperative scores. Mean postoperative scores FM/Control group were: Constant 63.5/74 (P=.07), rCS 82/88 (P=.18), DASH 38.9/20.7 (P=.009), VAS 3.8/2.8 (P=.2). Eighty-five percent of patients in the control group were satisfied with the surgery compared with 55% in the FM group (P=.03). Failure of the procedure was 60% in the FM group, and 30% in the control group (P=.056).
Fibromyalgia can be considered a prognostic factor of a poor postoperative outcome after an IASD. However the clinical improvement experienced by these patients over their preoperative situation leads us to recommend their surgical treatment when indicated.