Temporomandibular joint injuries and ankylosis in the cat

Objective: To evaluate cause, location, treatment, and the clinical outcome of traumatic temporomandibular joint (TMJ) lesions and TMJ ankylosis in cats. Methods: Cats with TMJ injuries were included in this study. Lesions were classified as luxations, fractures of the condylar process, and intra-articular temporal bone fractures. Signalment, cause and type of injuries, treatment methods, clinical outcome, complications and joint ankylosis were assessed and evaluated statistically. Results: Temporomandibular joint lesions were observed in 82 of 161 cats with maxillofacial injuries. One hundred forty-nine TMJ lesions were determined in 112 joints. Falling was the most common cause and fractures of the condylar process were the most common types of injuries. Isolated TMJ injuries and caudal TMJ luxations were mainly caused by falling. Condylectomy was used in ankylosis, chronic luxation, reluxation and in two cases with multiple TMJ lesions. Ankylosis was observed in 10.97% of cases and was generally observed in fracture combinations of condylar process and mandibular fossa (χ2 = 8.52; p <0.05). No significant relationship between age and development of ankylosis (χ2 = 3.995; p >0.05) was found. Conclusion: In contrast to previous studies, traumatic TMJ lesions were observed in a considerable amount of cats with maxillofacial injuries, and fractures of the condylar process were the most common type. Lesions caused by falling were mostly simple, whereas vehicular trauma caused more complicated lesions. Ankylosis did not appear as a rare condition. Any cat with TMJ injury is susceptible to the development of ankylosis.