Condylar Hyperplasia

§ overviewOverview

Persistent, self-limiting enlargement of the condyle, condylar neck and/or ramus caused by aberrant endochondral proliferation.

§ epidemiologyEpidemiology

Adolescents to young adults; slight female predilection; usually unilateral.

§ pathogenesisPathogenesis

Persistent proliferative activity of the condylar cartilage growth centre beyond skeletal maturity; oestrogen and IGF-1 implicated.

§ clinicalClinical Features

• 01Progressive facial asymmetry with chin deviation to the unaffected side (Type II) or ipsilateral (Type I)
• 02Unilateral posterior open bite / crossbite
• 03Occlusal cant
• 04Preserved TMJ function

§ differentialDifferential Diagnosis

• 01Fibrous dysplasia
• 02Osteochondroma of condyle
• 03Condylar tumour
• 04Ameloblastoma

§ investigationsInvestigations

• 01OPG, PA cephalogram, 3D CT
• 02Bone scintigraphy (99mTc-MDP): >10% uptake asymmetry = active
• 03SPECT for improved localisation

§ classificationClassification

• 01Obwegeser & Makek: Type I hemimandibular elongation, Type II hemimandibular hyperplasia, Type III combined

§ treatmentTreatment

• 01Active disease: high condylectomy (5 mm) to arrest growth ± orthognathic correction
• 02Burnt-out disease: orthognathic surgery alone (bimaxillary + genioplasty)
• 03Orthodontic decompensation before surgery

§ complicationsComplications

• 01Recurrence if condylectomy inadequate during active phase
• 02Facial nerve injury
• 03Malocclusion relapse

§ prognosisPrognosis

Excellent with correct timing; monitor with serial cephalometrics and bone scans.

§ examKey Examination Points

• 01Chin deviation direction discriminates Type I vs II
• 02Confirm activity before definitive surgery

§ revisionQuick Revision Summary

• 01Obwegeser I/II/III · bone scan for activity · condylectomy if active

§ vivaBDS Viva Questions

• 01Differentiate hemimandibular elongation and hyperplasia.
• 02How do you determine activity?
• 03Role of high condylectomy?

§ mcqsMCQs — Assessment (3)

§ relatedRelated Diseases