title: Surgical risk factors for condylar resorption after orthognathic surgery.
abstract: OBJECTIVE
  The purpose of this study was to look for surgical risk factors for condylar resorption after orthognathic surgery.
  
  
  METHODS
  Seventeen patients of a group of 452 patients who had undergone orthognathic surgery consecutively and who were in accordance with the inclusion criteria of this study showed postoperative condylar resorption (group I). Preoperative cephalometric characteristics and surgically induced movements of this group were compared with a control group of 17 of 452 patients (group II) in whom postoperative condylar resorption and skeletal relapse did not develop, despite mandibular retrognathism (ANB angle >4 degrees) and high mandibular plane angle (>40 degrees).
  
  
  RESULTS
  The kind of osteosynthesis used was not significantly different between the 2 groups. The amount of surgical advancements and the vertical movements of the jaws were not significantly different between the 2 groups. However, the distal (P =.005) and proximal (P =.007) mandibular segments were rotated significantly further counterclockwise in group I. Surgically induced posterior condylar displacement occurred significantly more frequently (P =.007) in group I.
  
  
  CONCLUSIONS
  Counterclockwise rotation of the distal and proximal mandibular segments and surgically induced posterior condylar displacement seem to be important surgical risk factors for postoperative condylar resorption. Therefore, these movements seem to be contraindicated in patients who are at high risk.
authors.affiliation: University Zurich and University Hospital Zurich, Switzerland.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hwang
authors.forename: P E
authors.initials: PE
authors.lastname: Haers
authors.forename: A
authors.initials: A
authors.lastname: Zimmermann
authors.forename: C
authors.initials: C
authors.lastname: Oechslin
authors.forename: B
authors.initials: B
authors.lastname: Seifert
authors.forename: H F
authors.initials: HF
authors.lastname: Sailer
mesh_terms: D000293:Adolescent; D000328:Adult; D001862:Bone Resorption / Q000209:etiology*; D002508:Cephalometry; D005260:Female; D006801:Humans; D019248:Jaw Fixation Techniques / Q000009:adverse effects; D016015:Logistic Models; D008312:Malocclusion, Angle Class II / Q000601:surgery; D008334:Mandible / Q000002:abnormalities / Q000503:physiopathology / Q000601:surgery; D019186:Mandibular Advancement / Q000009:adverse effects; D008335:Mandibular Condyle / Q000473:pathology*; D008336:Mandibular Diseases / Q000209:etiology*; D016017:Odds Ratio; D019647:Oral Surgical Procedures / Q000009:adverse effects*; D019340:Osteotomy, Le Fort / Q000009:adverse effects; D063173:Retrognathia / Q000601:surgery*; D012307:Risk Factors; D012399:Rotation; D018709:Statistics, Nonparametric; D013705:Temporomandibular Joint Disorders / Q000209:etiology*