The Association Between Cervical Foraminal Stenosis and Adhesive Capsulitis: An Imaging-based Case-Control Study.

Study Design: Retrospective single-center imaging-based case-control study.

Objective: To determine the association between cervical foraminal stenosis and adhesive capsulitis.

Summary Of Background Data: Patients with cervical spondylosis often exhibit shoulder symptoms. Cervical radiculopathies, particularly C5, can cause severe shoulder pain and reduced shoulder mobility, mimicking glenohumeral adhesive capsulitis (frozen shoulder), a common shoulder condition. This is the first study investigating the connection between adhesive capsulitis and cervical radiculopathy.

Methods: 438 patients who underwent glenohumeral hydrodistension between 2012 and 2019 were reviewed. Included were individuals with unilateral frozen shoulder investigated using ultrasound and cervical spine MRI to investigate cervical spondylosis. Foraminal stenosis at C3/4, C4/5, C5/6 and C6/7 was graded in axial T2 MRI, ipsilateral and contralateral to the adhesive capsulitis. The presence of foraminal stenosis ipsilateral to the frozen shoulder (cases) was compared with the contralateral side (control). McNemar's exact test was used to assess the strength of a correlation.

Results: Among 438 patients, 107 reported frozen shoulder and neck pain (24.5%), with 48 matching the study criteria. A significant association between ipsilateral frozen shoulder and C4/5 foraminal stenosis was observed (P=0.00000008636). Ipsilateral foraminal stenosis was observed in 57.3% of these cases, with bilateral stenosis in 29.1%. Additionally, 78% had neck pain on the same side as their frozen shoulder, and 44% had pain radiating to the shoulder. 48% patients underwent nerve-targeted interventions, with 44% addressing the C5 nerve (25% C5 steroid injection and 19% C4/5 anterior cervical discectomy and fusion).

Conclusion: A substantial association between C5 foraminal stenosis and ipsilateral frozen shoulder was found. C5 radiculopathy could be a risk factor for "neurogenic frozen shoulder". Those diagnosing frozen shoulder and cervicobrachialgia should recognize that frozen shoulder and C5 radiculopathy may coexist. A multidisciplinary approach involving both shoulder and spine specialists is recommended for a definitive diagnosis.