Temporomandibular joint ankylosis caused by chondroid hyperplasia from the callus of condylar neck fracture.
A patient who complained of difficulty in opening his mouth after condylar neck fracture 1 year ago presented typical features of temporomandibular joint ankylosis in clinical and radiologic examinations. To demonstrate a possible pathogenesis of temporomandibular joint ankylosis after condylar neck fracture, the fractured condylar portion removed was examined by histologic and immunohistochemical stainings. Interpositional gap arthroplasty was performed by removing the inferomesially displaced fractured condyle, and reconstruction with subcutaneous dermis to the previous vertical height was performed immediately. The fractured condylar portion was almost intact with slight erosion of the condylar cartilage. In the hematoxylin and eosin and Masson trichrome stainings, an extensive chondroid hyperplasia with abundant hyaline cartilage was shown in the removed condylar portion. There were also hyperplastic features of the synovial membrane, which were abnormally distributed throughout the chondroid tissues. In the immunohistochemical stainings of proliferating cell nuclear antigen (PCNA) and bone morphogenetic protein (BMP)-2 and BMP-4, the chondroid tissues were conspicuously hyperplastic and strongly positive for BMP-4 but sparse for BMP-2. From these results, we think that the hyperplastic chondroid tissue was derived from the callus of the primary fractured site of the condylar neck and propose that the chondroid tissue could proliferate continuously because of synovial tissue support from around the temporomandibular joint, resulting in temporomandibular joint ankylosis. This pathogenesis is quite different from those of other diaphyseal fracture of long bones.
Kim
Soung Min
SM
Department of Oral and Maxillofacial Surgery, College of Dentistry, Seoul National University, Seoul, South Korea.
Park
Jung Min
JM
Kim
Ji Hyuck
JH
Kwon
Kwang Jun
KJ
Park
Young Wook
YW
Lee
Jong Ho
JH
Lee
Sang Shin
SS
Lee
Suk Keun
SK
D000328:Adult; D000844:Ankylosis / Q000209:etiology*; D001178:Arthroplasty; D055396:Bone Morphogenetic Protein 2 / Q000032:analysis; D055415:Bone Morphogenetic Protein 4 / Q000032:analysis; D002146:Bony Callus / Q000473:pathology*; D002358:Cartilage, Articular / Q000473:pathology; D017102:Fracture Healing / Q000502:physiology; D006801:Humans; D051457:Hyaline Cartilage / Q000473:pathology; D006965:Hyperplasia; D008297:Male; D008335:Mandibular Condyle / Q000293:injuries* / Q000473:pathology; D008337:Mandibular Fractures / Q000150:complications*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D013583:Synovial Membrane / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000209:etiology*
C525718:BMP2 protein, human; C525809:BMP4 protein, human; D055396:Bone Morphogenetic Protein 2; D055415:Bone Morphogenetic Protein 4; D018809:Proliferating Cell Nuclear Antigen