We read the article by Stembirek et al. with great interest. The authors present a suitable hypermobility model in pigs that could also be used for subsequent research, which is very interesting. Nonetheless, two points regarding the methodology deserve further discussion.

Firstly, no jaw immobilization was applied following the injection, which might have affected the results. Autologous blood should be kept in place during the formation of granulation tissue as an adhesive agent. As animals do not restrict their jaw movement, immobilization is required for the optimum effect of the injection. The findings presented by the authors confirm the need for immobilization, because the upper joint cavity surfaces remained smooth without changes or adhesions at 4 weeks after the injection.

Secondly, hypermobility of the temporomandibular joint (TMJ) is not caused by the disc; the integrity of the joint capsule and ligaments is one of the main causes of luxation. Machon et al. suggested that laxity of the TMJ ligaments with the weakness of the capsule, joint architecture, and hyperactivity of the jaw musculature leads to dislocation. Therefore restrictive therapies should be directed at the ligaments, eminence, or musculature rather than the disc. Although intra-articular injection of autologous blood is beneficial indirectly by scarring, or as an adhesive agent, it should be emphasized that injection around the capsule and ligament would be more effective in the minimal invasive treatment of TMJ hypermobility.