Histological evaluation of the changes in temporomandibular joint capsule and retrodiscal ligaments following autologous blood injection

IntroductionIn recent years injection of autologous blood into the temporomandibular joint (TMJ) has been reintroduced as a treatment of chronic recurrent TMJ dislocation. The effects of this treatment on components of the TMJ is not fully understood. The purpose of this article is to evaluate the effects of autologous blood on TMJ capsule and the retrodiscal ligament.Material and methodsA total of 16 healthy adult country bred pig were used in this study. Autologous blood were injected into the upper joint space (4 ml) and around the capsule of TMJ unilaterally (1 ml). This procedure was then repeated on the opposite side only by using 5 ml of 0.9% saline. TMJ capsules and retrodiscal ligaments were examined four weeks following the injections.ResultsHistological examination of TMJs injected with autologous blood revealed fibrotic changes in 81.25% of the retrodiscal ligaments and 56.25% of the capsular areas. Whilst no changes were seen in the retrodiscal ligaments nor in the capsules of TMJs injected with saline alone.ConclusionThere is little published clinical data on the use of autologous blood injection and as such the mechanism of action is still unclear. The rate of induction of fibrosis within the retrodiscal ligaments in this study were similar to previously reported studies and case series. However, further studies to evaluate the mechanism of this safe and simple technique are needed.