Abstract
The coraco-acromial ligament (CAL) is partially resected during a subacromial decompression. Clinical studies have reported the regeneration of a structure which appears to be a new CAL. Histological studies of regenerated CAL have demonstrated an abundance of relatively acellular collagen fibrils orientated in the line of a ligament and mechanical testing of the regenerated tissue has properties similar to those of normal CAL. However it is still not clear whether this structure represents scar tissue or truly reformed ligament. Defining the major collagen constituent of this regenerated tissue would allow the distinction between ligament and scar tissue. Therefore the aim of this study was to examine the level of expression of types I and III collagen in regenerated coraco-acromial ligaments (CAL) in humans.
Samples of regenerated CAL were obtained during open surgery for repair of small rotator cuff tears at an average of 24 months (range 14 to 52) after arthroscopic subacromial decompression from 4 men and 3 women with an average age of 58 years (range 44 to 68). A standard protocol radio-active in-situ immunolocalisation technique was used to quantify the ratios of mRNA collagen I to collagen III in the samples.
The results demonstrated that the average ratio of collagen I to collagen III was 6.5. This ratio is similar to the value for normal hip capsule (5–6:1) and human posterior cruciate ligament (8:1).
We conclude that the reformed CALs are ligamentous structures, not scar tissue, and therefore represent truly regenerated ligaments.
These abstracts were prepared by Mr Cormac Kelly. Correspondence should be addressed to him c/o British Orthopaedic Association, Royal College of Surgeons, 35-43 Lincoln’s Inn Fields, London WC2A 3PN.
