Concomitant Rotator Cuff Tear with Frozen Shoulder: A Contemplation on the Necessity and Legitimacy of Magnetic Resonance Imaging Stratified by Age.

Background: Frozen shoulder (FS) is often accompanied by a rotator cuff tear (RCT), but it can be challenging to diagnose a concomitant RCT without imaging studies. Therefore, having practical criteria to identify patients requiring imaging studies at initial presentation with FS would lead to more cost-effective use of these studies. This study investigated the relationship between RCT and stiffness in patients with FS and whether this relationship was modified by patient age.

Methods: This study included 540 adults with shoulder pain who had ≥ 10° of limited passive range of motion in forward flexion, compared to the contralateral side. Patients were categorized into 2 groups depending on the degree of forward flexion stiffness: overhead stiffness (OHS) group, patients with ≥ 110° forward flexion (n = 349); and non-OHS group, patients with forward flexion < 110° (n = 191). The presence of concomitant RCT was determined by magnetic resonance imaging and compared between groups before and after stratification by age.

Results: The OHS group had increased odds of concomitant RCT, compared to the non-OHS group (odds ratio [OR], 4.99; 95% CI, 3.36-7.42). OHS was also significantly associated with a more severe grade of RCT (no tear, partial-thickness tear, or full-thickness tear) (OR, 4.42; 95% CI, 3.05-6.39). The odds of RCT in the OHS group, compared to the non-OHS group, increased with age (50-59 years: OR, 3.83; 95% CI, 1.96-7.48; 60-69 years: OR, 5.94; 95% CI, 3.14-11.26; and 70-79 years: OR, 7.67; 95% CI, 2.71-21.66).

Conclusions: Patients with FS and forward flexion range of motion ≥ 110° (i.e., OHS) at initial presentation had approximately 5-fold higher odds of concurrent RCT than patients with non-OHS. Moreover, in patients aged 50 years or above, these odds increased up to almost 8-fold. Therefore, we recommend confirming the rotator cuff integrity with magnetic resonance imaging in patients with FS and OHS.