Clinical outcome of arthroscopic capsular release for frozen shoulder: essential technical points in 255 patients

BACKGROUND The purpose of this study was to investigate the long-term clinical outcome and its related factors regarding the severity of adhesion of CH ligament over long head of biceps (LHB) after shoulder arthroscopic capsular release for frozen shoulder with technical points in 255 patients. METHODS We performed arthroscopic capsular release for frozen shoulder in 267 shoulders of 255 patients, 112 males and 143 females, with mean age of 56.39 years, mean disease duration periods of 0.934 years for conservative treatment, and mean follow-up periods of 5.6 years. The frozen shoulders were divided based on the severity of adhesion between CH ligament over LHB: those with slight degree of synovitis, no adhesion by obtuse rod, and slight thickness of the released capsule (type A), those with moderate degree of synovitis, moderate adhesion of the LHB by obtuse rod, and moderate thickness of the released capsule (type B), and those with severe degree of synovitis, severe adhesion of the LHB by obtuse rod, and severe thickness of the released capsule adhesion and a flatly shaped LHB (type C). We assessed the clinical factors related to the scoring of the shoulders by the criteria of the American Shoulder and Elbow Surgeons (ASES) and the relationship with severity of LHB adhesion. RESULTS The ASES scores improved at 5 years postoperatively in all three groups significantly. The range of motion also significantly improved in all three groups significantly. The severity of the LHB adhesion over the CH ligament was confirmed to influence the ASES scores before and after the arthroscopic capsular release. There was a significant difference between type A and type B (p < 0.0001) or type C (p < 0.0001) before and after surgery. Logistic regression analysis showed disease duration, diabetes mellitus (DM), and ASES score were significantly associated to the severity type of LHB, especially DM has high odds ratio and was a risk factor for LHB adhesion. There is no adverse event including dislocation or axillary nerve injury and recurrence after arthroscopic capsular release at 5 years after surgery. CONCLUSIONS The long-term results of arthroscopic capsular release in frozen shoulder were confirmed in 255 patients. The severity of LHB adhesion over the CH ligament, a pathological condition related to DM as a risk factor, seems to play an important role in the functional outcome. Therefore, the sufficient release of LHB was essential technical point for arthroscopic capsular release in frozen shoulder.