To describe the clinical, radiographic, and arthroscopic characteristics of anchor-induced arthropathy after arthroscopic shoulder stabilization procedures and secondarily, to define risk factors for the development of anchor-induced arthropathy.
A total of 23 patients who underwent revision arthroscopic shoulder surgery and were diagnosed with glenohumeral arthropathy were retrospectively identified from prospectively collected data registries between January 2000 and May 2018. Data included initial diagnosis and index procedure performed, presenting arthropathy symptoms including duration, and exam findings prior to revision surgery. Pre-revision imaging was used to assess presence of glenohumeral osteoarthritis and chondromalacia, anchors/sutures, loose bodies, and labral pathology. The same parameters were recorded intraoperatively during revision surgery. Descriptive statistics were performed for demographic data and means with standard deviations were calculated for continuous data. A McNemar-Bowker test was used to analyze marginal homogeneity between preoperative radiographs and intraoperative findings.
Mean age at presentation was 33.4 +/- 11.7 years (range = 16 to 59, 17 male; 6 female). More than half (13/23) developed significant symptoms within 10 months after index arthroscopic procedure (mean 36.3 ± 50.0 months, range 2.3 to 166.1 months) with pain (87%) and loss of motion (100%). Plain radiographs demonstrated humeral osteoarthritis in 57% (13/23) of patients, MRI revealed recurrent labral pathology in 19/23 (83%) patients, implant concerns in 12/23 (52%), and loose bodies in 12/23 (52%). Intraoperatively, all had evidence of osteoarthritis; 22/23 (96%) had prominent implants. Humeral head chondromalacia was present in 21/23 patients (91%), the majority of which was linear stripe wear, and 6/23 (26%) had severe global glenohumeral osteoarthritis. Statistical analysis revealed 54.5% (95% CI [0.327, 0.749]) sensitivity of MRI identification of proud implants with a specificity of 100% (95% CI [0.055,1]. The ability of MRI to accurately assess chondromalacia of the humeral head (p = 0.342) or glenoid (p= 0.685) was not statistically significant.
Anchor arthropathy is characterized by symptoms of pain and stiffness and in many cases presents very early after stabilization surgery (<10 months). Although implants were implicated in the majority of humeral head chondromalacia, the timing of implant related damage is unknown. MRI’s may produce false negative identification of proud implants and can be a poor predictor of the severity of chondromalacia and intraarticular pathology, thus a high index of clinical suspicion is necessary in patients with stiffness and pain postoperatively.
Clinical Relevance: Surgeons should have a low threshold for early arthroscopic intervention to assess the painful and stiff shoulder after instability repair if anchor arthropathy is suspected.