AtlasTMJTMJ Ankylosis

TMJ Disorders

TMJ Ankylosis

Bony or fibrous fusion of the mandibular condyle to the glenoid fossa producing limited or absent mouth opening; a paediatric-onset case causes 'bird-face' deformity.

Classification
Sawhney I–IV
Protocol
Kaban 6 steps
Child graft
Costochondral

§ overviewOverview

Restriction of jaw movement caused by fusion of the mandibular condyle to the temporal bone through fibrous, bony or fibro-osseous tissue.

§ etiologyEtiology

  • 01Trauma (most common — 50%)
  • 02Infection (otitis media, osteomyelitis)
  • 03Systemic (ankylosing spondylitis, rheumatoid)
  • 04Radiotherapy
  • 05Congenital

§ epidemiologyEpidemiology

Children and young adults; unilateral more common; more prevalent in developing countries due to untreated trauma/infection.

§ clinicalClinical Features

  • 01Reduced or absent mouth opening
  • 02Micrognathia (unilateral: chin deviation to affected side; bilateral: bird-face)
  • 03Sleep-disordered breathing/OSA
  • 04Poor oral hygiene, dental crowding

§ investigationsInvestigations

  • 01OPG, PA cephalogram
  • 02CT / 3D CT (gold standard for bony architecture)
  • 03MRI to assess disc

§ classificationClassification

  • 01Sawhney (1986): Type I fibrous, Type II fibro-osseous with condyle intact, Type III bony bridge with condylar destruction, Type IV extensive bony ankylosis obliterating architecture

§ treatmentTreatment

  • 01Aggressive early release to prevent deformity and OSA
  • 02Kaban protocol: (1) aggressive gap arthroplasty ≥1.5 cm, (2) ipsilateral coronoidectomy, (3) contralateral coronoidectomy if opening <35 mm, (4) interpositional material (temporalis flap or alloplastic), (5) rigid fixation with early mobilisation, (6) aggressive physiotherapy for ≥6 months
  • 03Costochondral graft in growing children; TMJ prosthesis in adults

§ complicationsComplications

  • 01Re-ankylosis
  • 02Facial nerve injury
  • 03Growth disturbance
  • 04OSA

§ prognosisPrognosis

Good with strict adherence to Kaban protocol and physiotherapy; re-ankylosis if immobilised.

§ examKey Examination Points

  • 01Measure MIO
  • 02Assess airway (OSA)
  • 03Type on CT

§ revisionQuick Revision Summary

  • 01Sawhney classification · Kaban protocol · aggressive physio

§ vivaBDS Viva Questions

  • 01Sawhney types?
  • 02Kaban protocol?
  • 03Choice of interpositional material?

§ mcqsMCQs — Assessment (3)

Question 1

Most common cause:

Question 2

Preferred graft in growing child:

Question 3

Sawhney Type III describes:

References

  1. Kaban LB. J Oral Maxillofac Surg 2009

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