A sheep model of intracapsular condylar fracture.
OBJECTIVE
An animal model of a condylar head fracture similar to a type B intracapsular fracture in humans was created. The effect of this model on mandibular function and morphological changes of temporomandibular joint (TMJ) structure was evaluated.


METHODS
Ten sheep were divided into 3 groups, sacrificed at 1 week (2 sheep), 4 weeks (4 sheep), and 12 weeks (4 sheep) after surgery. The right side of the TMJ was considered the surgical group; the left side, the control group. The anterior and posterior attachments of the discs were cut, and an oblique vertical osteotomy was made from the lateral pole of the condyle to the medial side of the condylar neck. The condyle fragment was pushed together with the disc anteriorly, inferiorly, and medially. The lateral side of the condylar stump was sutured to the capsule to limit movement. Preoperative and postoperative body weight, maximum mouth opening, lateral excursions, and x-ray and computed tomography (CT) findings in the 3 surgical groups and the control group were recorded. The SPSS software program was used for all statistical analyses.


RESULTS
There were no significant differences in weight loss and left lateral movement among the 3 surgical groups, but maximum mouth opening and the right lateral movement decreased significantly in the 4-week and 12-week surgical groups. X-rays demonstrated severe bone erosion and new bony outgrowth in the lateral side of the condylar stump and a narrowed, indistinct joint space in these 2 groups. Three-dimensional reconstruction of CT images showed changed contours of the condylar stump, condylar fragment and articular eminence in all 3 surgical groups.


CONCLUSIONS
This study demonstrates progressive changes toward ankylosis and pathological changes in sheep TMJ over time consistent with what has been found in humans.
Long
Xing
X
Department of Oral and Maxillofacial Surgery, Key Laboratory for Oral Biomedical Engineering of the Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wutan, Hubei, People's Republic of China. longxing_china@hotmail.com
Goss
Alastair N
AN
D000818:Animals; D000844:Ankylosis / Q000209:etiology; D001862:Bone Resorption / Q000209:etiology; D004195:Disease Models, Animal; D005096:Exostoses / Q000209:etiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D017746:Joint Capsule / Q000293:injuries*; D004204:Joint Dislocations / Q000473:pathology / Q000503:physiopathology; D008297:Male; D008335:Mandibular Condyle / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology; D008336:Mandibular Diseases / Q000209:etiology; D008337:Mandibular Fractures / Q000209:etiology*; D010003:Osteoarthritis / Q000209:etiology; D010026:Osteosclerosis / Q000209:etiology; D016059:Range of Motion, Articular / Q000502:physiology; D012756:Sheep; D013701:Temporal Bone / Q000473:pathology; D013704:Temporomandibular Joint / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology; D019224:Temporomandibular Joint Disc / Q000293:injuries; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods