Temporomandibular joint luxation in the cat: Diagnosis and management

Temporomandibular joint (TMJ) injuries in the cat frequently result in luxation and are commonly seen with other maxillofacial injuries (1–3). A luxation is a condition in which the articular surfaces of a joint are completely dislocated (2,4). Patients with TMJ luxation typically present with an inability to completely close the mouth due to mandibular drift resulting in maligned dental arches (3,4; Figure 1). Temporomandibular joint luxations are usually unilateral and rostrodorsal, with the mandibles shifted to the side opposite the luxation. Initial oral examination is often limited to observation of the malocclusion and the inability of the patient to completely close the mouth. Complete oral examination is necessary to rule out additional trauma to teeth and other maxillofacial structures; this requires anesthesia. A detailed preanesthetic evaluation is necessary due to the traumatic nature of TMJ luxation and this should include a physical examination, a neurologic examination, serum biochemistry profile, complete blood (cell) count (CBC), thoracic radiographs, abdominal ultrasound, and an electrocardiogram (2). After all other systems have been evaluated for additional injuries, anesthesia is induced and a thorough oral evaluation is performed. The mandibles and maxillae are carefully palpated while attempting to open and close the mouth. Indications of jaw fracture include crepitus on palpation and the ability to close the mouth with gentle pressure (2). If the TMJ is luxated, the malocclusion and the inability to close the mouth remain with increased forces (2). Gentle forces are recommended in an effort not to cause additional traumatic injuries such as mandibular fractures