Structures contributing to the shoulder contracture in brachial plexus birth palsy. An intraoperative biomechanical study

Internal rotation contracture of the shoulder is a common sequel of the brachial plexus birth palsy. The purpose of this study is to describe the surgical method used in our centre and to measure the effect of sequentially releasing several anatomical structures that have been ascribed as the cause of the contracture. Twenty-four consecutive patients were operated on with an open release. We documented the increase in passive external rotation after each surgical step. We found small gains in passive external rotation when performing coracoidectomy and division of the upper part of the subscapularis tendon; 4° (95% confidence interval [CI] 2°–6° p < 0.01) and 6° (95% CI 4°–8° p < 0.01), respectively. A substantial gain in external rotation occurred when dividing the entire subscapularis tendon, 43° (95% CI 38°–48°, p < 0.01). Our findings indicate that a clinically relevant surgical release of the contracture requires lengthening of the entire subscapularis musculo-tendinous unit. Level of evidence: IV

Platelet-rich plasma as a potential prophylactic measure against frozen shoulder in an in vivo shoulder contracture model

Introduction Frozen shoulder (adhesive capsulitis) is a common painful and functionally-limiting disease affecting around 2% of the population. So far, therapeutic options are limited and often unsatisfactory. Platelet-rich plasma (PRP) has been used as a treatment option in other orthopedic diseases since it contains growth factors that stimulate tissue repair. So far, the effect of PRP on frozen shoulder lacks evidence. We hypothesized that PRP may be valuable in the prophylaxis and treatment of secondary frozen shoulder due to capsular remodeling. Materials and methods An experimental study of an in vivo frozen shoulder model was conducted. Twenty Sprague–Dawley rats underwent surgery in which the body of the scapula was connected to the humerus with a high-strength suture. Two groups of 8 weeks survival time were allocated; a treatment group with one intraoperative injection of PRP into the glenohumeral joint (n = 10) and a control group without PRP (n = 10). The primary outcome was the structural change in the posterior synovial membrane of the posterior and inferior part of the glenohumeral joint using a semi-quantitative grading from 0 (lowest) to 3 (highest). Results The posterior synovial membrane structural changes were significantly lower in the PRP group (median = 1 [interquartile range (IQR) = 0–1]) compared to controls (median = 2 [IQR = 1–3]) (p = 0.028). There were no differences for the remaining synovial membrane changes and fibrous capsule responses between groups. Conclusions In this in vivo shoulder contracture model, PRP injections seem to reduce the histological severity grade of some parts (i.e., posterior synovial membrane changes) of the secondary frozen shoulder without causing any side effects. It may be considered to investigate this effect further in future studies as a potential prophylaxis of secondary frozen shoulder (e.g., in operated or immobilized shoulders) or as a treatment option for patients with frozen shoulder in the early stage.