Glenohumeral osteoarthritis: frequency of underlying diagnoses and the role of arm dominance-a retrospective analysis in a community-based musculoskeletal practice.

Patients with shoulder pain are commonly seen in adult primary care, and are typically referred to musculoskeletal specialists when their symptoms are persistent. Rotator cuff disorders (RCD) most commonly underlie non-traumatic shoulder pain in adults, and glenohumeral osteoarthritis (GHOA) has been considered to be relatively uncommon (Nakagawa et al., J Shoulder Elb Surg 8:580-584, 1999). Our impression has been that GHOA affects significant numbers of patients, is less well studied, and may be under recognized. Among adults referred to a musculoskeletal practice for shoulder pain evaluation, we determined the relative numbers of patients with a clinical diagnosis of RCD and GHOA by age and by gender, assessed the role of handedness in GHOA, and the proportion of patients with underlying conditions (versus primary or idiopathic GHOA). We also assessed the frequency of progression to operative management over a defined time interval. This is a retrospective case series of patients presenting to a musculoskeletal referral practice for shoulder pain. Patients with a clinical diagnosis of GHOA were identified with electronic medical records, and then assessed for demographic data, physical measures, comorbidities, and progression to surgical intervention within 2 years. Among non-traumatic shoulder pain patients presenting to our practice during a 9-month period in 2013, RCD was diagnosed in 984 patients, and GHOA was diagnosed in 209 patients. 152 of the GHOA patients (73%) had primary (idiopathic) GHOA, without associated inflammatory conditions or cuff arthropathy. Primary GHOA affected the dominant arm in 38.7%, the non-dominant arm in 33.8%, and was bilateral in 27.5%. Patients diagnosed with primary GHOA were older than those with RCD (69.8 ± 12.2 vs 57.1 ± 15.1; p = 0.0001). Women represented 54% of cases of primary GHOA, and their presentation age was older than men (72.9 ± 11.2 vs 66.1 ± 12.4; p = 0.0005). Primary GHOA patients had a mean BMI of 31.0 ± 6.3, 48.7% had hyperlipidemia and 57.2% had hypertension. 24.3% were treated surgically within 2 years of follow-up. GHOA is a significant cause of shoulder pain in older age groups, and the majority of these patients have primary (idiopathic) GHOA. Primary GHOA affects dominant and non-dominant arms at similar rates, suggesting that anatomical and/or systemic factors are more important than overuse in GHOA pathogenesis. Given the prominence of GHOA in older age groups, changes in population demographics, and limitations of non-operative treatment, continued increases in shoulder replacement surgery are likely. Efforts to further understand GHOA pathogenesis and develop new, more effective therapies are advocated.