Restriction of Passive Glenohumeral Abduction Combined With Normal Passive External Rotation Is a Diagnostic Feature of Calcific Tendinitis

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.

Biomarkers associated with idiopathic frozen shoulder: a systematic review

Background: The pathophysiology of idiopathic frozen shoulder (FS) remains poorly described. There is a lack of differentiation between idiopathic and secondary cause. The aim of this systematic review was to summarize the evidence regarding the pathophysiology of idiopathic FS on a molecular level and emphasize the clinical relevance. Methods: A database search of Medline, EMBASE and Cochrane Central Register of Controlled Trials from inception to April 2018 was performed. Participants who underwent previous injections or surgeries were excluded. A thorough selection and quality assessment process using the Cochrane Risk of Bias assessment tool and the Joanna Briggs Institute Critical Appraisal Checklist was conducted by two reviewers independently. Results: A total of 15 studies analyzing 333 study subjects were included. Twelve studies evaluated capsular tissue and three studies investigated blood samples. The tissue samples revealed increased expression of various inflammatory cytokines including interleukins, cyclooxygenase and tumor necrosis factor. Several types of acid-sensing ion channels (ASIC1 and ASIC3) were associated with disturbed neurogenesis and melatonin-regulated pain mechanism. The blood samples showed prevalence of specific interleukin and metalloproteinase genotypes. A decreased matrix metalloproteinase/tissue inhibitor of metalloproteinase ratio was found both in tissue and blood. Conclusion: The findings indicate an abnormal local neurogenesis with possible regulation through melatonin. The disturbance in remodeling of the extracellular matrix and in collagen translation, together with a persistent inflammation and an impaired healing, all interact in the process that leads to persistent fibrosis. There is global fibroplasia with localized anterior capsule contracture.