Meniscus or not: The radio-humeral synovial folds & its clinical importance

Introduction: Synovial folds present within the humero-radial compartment of elbow joint are prone to chronic inflammation in repeated users of elbow joint, mainly in athletes. Generally, these conditions are well managed with conservative medications, but if not cured, arthroscopic guided resection is suggested by researchers for maximum post-operative painless movement restoration. Aim: Aim of the present study was to find out the incidence of synovial folds of humero-radial part of synovial joint and gross structural variability of these folds along with histological structural details. Materials and Methods: 50 elbows from 25 embalmed cadavers were dissected in between March 2022 to February 2024. Incidence, morphology & morphometry of synovial folds were recorded. Part of the folds dissected out and stained with Hematoxylin eosin stain after tissue processing. Results: Posterolateral synovial fold is present in all the elbows followed by anterior fold which is present in 71% cases. Incidence of lateral fold and olecranon fold was almost similar 28% and 27% in sequence. Postero-lateral folds are largest in dimension, about 26.4 mm in length, 4.8mm in width and 2.9mm in thickness followed by anterior fold and lateral fold. The olecranon fold is smallest in all the dimensions measuring about 3.2mm in length, 2.7mm in width and 1.6 mm thickness. In hematoxylin eosin staining, it was found that all the folds are made up of fibrous tissue (predominantly collagen) without any chondrocytes. More specifically in the lateral synovial folds the collagen fibres are densely packed around an axis with very less amount of loose areolar tissue, but in rest of folds the collagen fibres are arranged loosely. Conclusion: Presence of such fibrous plica within the interposed surfaces of humero-radial part of elbow joint must be kept in mind during diagnosing and managing patients of persistent /chronic lateral elbow pain. Chronic inflammation of these plica or folds results into thickening of the folds which restrict the joint mobility and produces snapping elbow syndrome.