AtlasTMJCondylar Hyperplasia

TMJ Disorders

Condylar Hyperplasia

aka CH · Unilateral Condylar Overgrowth

Unilateral non-neoplastic overgrowth of the mandibular condyle producing progressive facial asymmetry, cross-bite and open-bite in adolescents.

Classification
Obwegeser I/II/III
Activity test
SPECT bone scan
Rx
High condylectomy

§ 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)

Question 1

Investigation to determine activity:

Question 2

Chin deviates AWAY from affected side in:

Question 3

Treatment of active CH:

References

  1. Obwegeser HL. J Maxillofac Surg 1986

Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.