The radiological fate of dermis-fat grafts in the human temporomandibular joint using magnetic resonance imaging.

The purpose of this study was to investigate the radiological fate of the dermis-fat graft within the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). Fifteen patients with dermis-fat grafts placed in 17 TMJs following discectomy for severe internal derangement were divided into 3 equal groups according to the time lapse between TMJ surgery and the MRI investigation: 0-6 months, 7-23 months and 2 or more years. The radiological presence of fat was found within the joint or surrounding the condyle in all 17 operated joints. The interpositional material found within the radiologically defined joint space was mainly grey (Grade 3, 12 joints), suggesting tissue change to other than fat, i.e. scar or granulation tissue. Two joints showed interpositional material entirely composed of fat (Grade 1), while 3 joints showed heterogeneous material composed of fat interspersed with grey tissue (Grade 2). There was no statistically significant difference in size of fat graft between the time intervals studied. Fat was present in similar quantities within or surrounding all joints regardless of the time lapse since surgery. Intermittent compressive forces of the joint may act as a negative influence on the growth and maintenance of fat tissue within the joint space itself.