Risk factors for recurrence of frozen shoulder after shoulder manipulation under ultrasound-guided cervical nerve root block.

BACKGROUND: This study aimed to investigate risk factors for recurrence of frozen shoulder after shoulder manipulation under ultrasound-guided cervical nerve root block (MUC).

METHODS: We retrospectively reviewed 135 frozen shoulders in 121 patients who underwent MUC. We defined frozen shoulder as a limited shoulder range of motion (ROM) (passive forward flexion <120°, external rotation <30°, or internal rotation lower than L3). Patients fulfilling any one criteria were considered to have frozen shoulder. If patients continued to have severe pain and limited ROM at 3 months after MUC, we defined as recurrence of frozen shoulder and they were offered a further MUC or arthroscopic capsular release (ACR). We compared the ROM, Constant Shoulder (CS) score, and University of California, Los Angeles score before and 3 months after MUC between patients with the successful of MUC group (Success group) with those recurrence of frozen shoulder who required a further MUC or ACR group (Recurrence group). Multiple logistic regression analysis was used to identify risk factors for recurrence of frozen shoulder after MUC.

RESULTS: Patients who underwent MUC were retrospectively enrolled and divided into: the successful of MUC group (Success group, n = 112) and required a further MUC or ACR group (Recurrence group, n = 9). The Recurrence group had significantly lower external rotation and CS score before MUC than those in the Success group ( P  < .05). The Recurrence group showed significantly inferior all ROM and functional scores 3 months after MUC ( P  < .05). The levels of blood glucose and hemoglobin A1c both before and 3 months after MUC in the Recurrence group showed inferior compared with those of Success group. The difference, although not statistically significant, trended towards significance (before MUC/3 months after MUC; the glucose levels P  = .06/.06, the hemoglobin A1c levels P  = .07/.09, respectively). The visual analog scale pain score (at rest, during activity, at night) both before and 3 months after MUC in the Recurrence group showed significantly higher scores compared with those of Success group ( P  < .05). Multiple logistic regression analysis revealed that lower CS score before MUC was independent risk factor for recurrence of frozen shoulder after MUC.

CONCLUSION: The overall incidence of recurrence of frozen shoulder after MUC was 7.4%. The lower CS score before MUC was an independent risk factor for recurrence of frozen shoulder after MUC. Moreover, patients in the Recurrence group tended to have poorly controlled diabetes and higher visual analog scale pain score both before and 3 months after MUC.