Summary

At the mean follow-up period with 3.7 years for primary frozen shoulder, 72.2% revealed subjective satisfaction for current shoulder status and 39.3% revealed persistent motion deficit. Diabetes, male, longer duration of symptoms, and bilateral involvement were poor prognostic factors of primary frozen shoulder.

Abstract

Purpose

Although numerous studies have suggested that primary frozen shoulder (FS) is a self-limiting disease with most cases recovering within 2 years, its natural history is still controversial. The aims of this study were to evaluate the natural history of primary FS and to determine its predictors of clinical outcome.

Materials And Methods

Two-hundred and thirty-four shoulders (216 patients) treated by conservative treatment for primary FS were included. The mean follow-up period was 3.7 years (range, 2-10.4 years). Initial evaluation included demographics, stereotyped detail medical history, and clinical assessments for shoulder status. Questionnaires including the visual analogue scale (VAS) pain score, American Shoulder and Elbow Surgeons (ASES) score, subjective shoulder value (SSV), range of motion (ROM) and satisfaction grading (5 grading; very satisfied, satisfied, fair, dissatisfied, very dissatisfied) for current shoulder status were assessed at the final follow-up.

Results

The mean age at symptom onset was 55.9 years and the mean duration of symptoms was 9.5 months. Women affected more commonly than men (1.6:1.0). Thirty-three patients (15.3%) had bilateral involvement. The mean VAS pain score, ASES score, SSV significantly improved from 6.7 ± 1.8, 37.0 ± 13.2, 40.1 ± 14.7 % at the time of initial evaluation to 1.5 ± 2.1, 87.6 ± 18.0, 85.0 ± 19.0 % at the final follow-up evaluation (all P < 0.001). According to satisfaction grading at the final follow-up, 101 shoulders (43.2%) were very satisfied, 68 (29.1%) satisfied, 37 (15.8%) fair, 20 (8.5%) dissatisfied, and 8 (3.4%) very dissatisfied. According to ROM grading, 141 shoulders (60.3%) had normal ROM, 70 (29.9%) mild motion deficit (< 25%), 18 (7.7%) moderate motion deficit (25% to 50%), and 5 (2.1%) severe motion deficit (> 50%). In the view point of satisfaction grading, the presence of diabetes (P = 0.090), male (P = 0.044), contra-lateral involvement (P = 0.011), simultaneous bilateral involvement at first visit (P = 0.016) and long duration of symptoms at first visit (P = 0.002) were associated with poor outcomes at final follow-up. Depending on final ASES scores, the presence of diabetes (P = 0.030), contra-lateral involvement (P = 0.034), simultaneous bilateral involvement at first visit (P = 0.042) and long duration of symptoms at first visit (P = 0.017) were associated with poor outcomes.

Conclusions

At the mean follow-up period with 3.7 years, 72.2% revealed subjective satisfaction for current shoulder status and 39.3% revealed persistent motion deficit. Diabetes, simultaneous and sequential bilateral involvement, and longer duration of symptoms were poor prognostic factors of primary FS.