Does Soft Tissue Injury Affect Intracapsular Condylar Fracture Healing?

The soft tissue healing patterns of mandibular intracapsular condylar fracture (ICF) after closed treatment have not been well characterized. The purpose of the present study was to classify the injury and healing patterns in adult patients using magnetic resonance imaging (MRI) evaluation.

The present study represents a retrospective review of MRI examinations performed on patients treated with closed reduction of an ICF from 2010 to 2013. The MRI scans used for comparison were taken at 1 week and at least 3 months after the injury. These studies were used to identify the common patterns of hard and soft tissue derangements. The predictor variable was the type of soft tissue injuries, categorized as anteromedial displacement of both the disc and the fractured bony fragment, anteromedial displacement of the bony fragment with the disc remaining over the residual ramus, tear of the retrodiscal tissue or capsule, and joint effusion. The outcome variables were the MRI comparisons of the disc position, healing status of the retrodiscal tissue and capsule, and resolution of joint effusions.

Twelve patients, all with ICFs, were included in the present study. Immediately after injury, all 17 fractures (100%) showed anteromedial displacement of both the disc and the fractured condylar fragment, and 10 fractures (58.8%) showed anteromedial displacement of the condylar fragment with the disc remaining over the residual condyle. Also, 11 (64.7%) showed evidence of perforation of the retrodiscal tissue, and 7 (41.2%) showed tears in the capsule. Finally, all 17 (100%) exhibited joint effusions. At 3 months after injury, all 17 fractures (100%) continued to exhibit displacement of both the disc and the condylar segments. Also, 15 fractures (88.2%) showed elongation of the disc and thickening of the retrodiscal tissue, 2 fractures (11.8%) had developed osteoid hyperplasia and meniscal perforation, and 6 fractures (35.3%) showed resolution of previous joint effusions. Finally, 17 fractures (100%) showed reactive bone formation at the condylar head.

ICFs treated with closed reduction consistently result in a specific pattern of temporomandibular joint pathologic features. These pathologic features are characterized by anteromedial displacement of the articular disc, elongation and thickening of the retrodiscal tissue, and reactive bone formation at the condylar head. The presence of a portion of the disc between the residual condyle and the fossa prevented the development of osteoarthritis and ankylosis. Perforation of the bilaminar tissue and contact between the residual condyle and the fossa promoted osteoarthritic changes and ankylosis.