Internal derangement

Content

• Introduction

• Etiology

• Biomechanics of TMJ

• Biomechanics of derangement

• Treatment

Introduction

• Anteromedial displacement of disk associated with posterosuperior displacement of condyle in closed joint

• Problems related to TMJ – Developmental – Diseases – Dysfunctions

• Two major symptoms are pain and dysfunction

• Pain originates only when soft tissue surrounding the joints are damaged

• Dysfunction disruption of normal movement and joint sounds – Click– Pop– Crepitations

• Catching sensation or lock

Etiology

• Acute macrotrauma

• Chronic microtrauma

• Developmental defects

Acute macrotrauma

• Blow to the mandible

• Mandibular whiplash – extreme translation – Injury to retrodiscal tissues and ligaments

• Mandibular hyperextension – Oral surgical procedures – During intubation

Chronic microtrauma

• Low grade trauma over a long period of time

• Overloading of the joint and disturbing the relationship of the condyle with disc and articular eminence

• Bruxism or clenching, loss of posterior teeth

• Disc lacks blood supply hence does not have capacity for cellular metabolism

Developmental defects

• Hypoplastic condyle

• Hyperplastic condyle

• Skeletal and facial asymmetry

Biomechanics of TMJ

• Two compartments • Only rotational

between condyle and disc – Discal ligament – Inferior lamina – Capsular ligament

• Interarticular pressure • Superior pterygoid

muscle • Morphology of the

disc

Biomechanics of TMJ

Biomechanics of internal derangement – single click

Reciprocal click

Functional dislocation with reduction

Without reduction or closed lock

Adhesion

Summary of continuum 1. Normal joint 2. Loss of normal condyle function

1. Microtruam 2. Microtruama

3. Abnormal translatory movement between disc and condyle 4. Poserior border of disc becomes thinned 5. Further elongation of discal and retrodiscal ligaments6. Disc becomes functionally displaced

1. Single click2. Reciprocal click

7. Disc becomes functionally displaced1. Dislocation with reduction (catching)2. Dislocation without reduction (closed lock)

8. Retrodiscitis 9. Osteoarthritis

Factor predisposing to disc derangement

• Steepness of articular eminence – Pt with steep eminence

• Morphology of condyle and fossa – Flat condyle against V shaped fossa

• Joint laxity – More lax joints are predisposed

• Attachment of superior lateral pterygoid – Attachment more to disc and less to the

codylar neck

Inflammatory joint disoreders

• Synovitis

• Capsulitis

• Retrodscitis

• Osteoarthritis

Patient evaluation – history

1. Description of problem in patients own words 2. Location of symptom 3. Length of time pt is having problem 4. How often pt has symptom 5. An particular event precede symptom6. Character of pain 7. What type of noises pt is aware of in the joints 8. History migraine and bruxism 9. Type of treatment pt has previously received

Examination - Opening

• Normal opening 40- 54 mm

• Opening of 27 mm can be due to acute closed lock

• If opening is less than that consider pain, adhesion ankylosis or extracapsular problem

Lateral excursion

• Most imp to differentiate between extra and intracapsular pathology

• In healthy joint ratio between maximum opening and translation is 4:1

• So if maximum opening is 40 mm then translation is 10 mm ( measured in lateral excursive movement)

Lateral excursion

• Ratio will help to differentiate between extra and intracapsular pathology

• Eg- 40 mm maximum opening and 5 mm lateral motion then problem is intracapsular

• 30 mm maximum opening and 10 mm lateral motion problem is extracapsular

• So if joint can translate it can rotate, but if it can rotate it will not necessarily translate

• Translation is primary measurement of intracapsular limitation and is the motion most often affected in joint disorder

• Rehabilitation should be directed towards the improving translatory movement

Deviation

Selective loading

Joint noise

• Early, midway or late

• Later the click during opening more sever is the problem

• Early during closing more sever the problem

• Crepitus is evidence of change in osseous contour

Treatment

• Nonsurgical – Definitive – eliminating etiology – Supportive – directed towards altering

patients symptoms

• Surgical

Definitive – for occlusal factors

• Reversible –– Occlusal appliances for optimum condyle disc

relationship

• Irreversible –– Selective grinding of the teeth, restorative

procedure or orthodontic treatment

Emotional stress

• Stress increase resting activity of muscles and also bruxism

• Identify the emotional stress

• Patient awareness

• Restrictive use

• Voluntary avoidance

• Relaxation therapy

Trauma

• Macrotruama

• Microtruama (bruxism or clenching)

Parafunctional activity

Supportive therapy - Pharmacologic

• Analgesic

• Corticosteroids

• Anxiolytic

• Muscle relaxant

• Local anesthetics

Physical therapy

• Thermotherapy – Initial condition of decreased blood flow to tissue is responsible

for myalgia

• Coolant – Relaxation of muscles that are in spasm – Should be kept till numbness occurs

• Ultrasound – Increase in temperature deeeper than the surface heat – Seprates colllagen fibers hence increases flexiblity of tissues

• Phonophoresis – Administer drugs through the skin by use of ultrasound

• Iontophoresis

• Transcutaneous electrical nerve stimulation– Continuous Electrical stimulation of cutaneous

nerves at subpainful level– Low amperage, low voltage biphasic current – Sensory counterstimulation – Constant impulses prevent painful stimuli

reaching the brain

Surgical

Arthrocentesis

• Patient who fail conservative measures are candidates for Arthrocentesis.

• Lavage and Iysis of the joint space allows for removal and dilution of inflammatory mediators, which may contribute to reduction of pain.

• Elevated protein levels in synovial fluid parallel the degree of inflammation because of increased permeability of the synovial membrane to plasma proteins.

Indications

1. Acute and chronic limitation of opening because of anteriorly displaced disk without reduction

2. Chronic pain with good range of motion and anterior disc displacement with reduction

3. Degenerative osteoarthritis

Contraindications

• Those patients who have not undergone appropriate conservative non-surgical and pharmacologic treatment,

• Bony or fibrous ankylosis,

• Have extracapsular source of pain.

• Disk perforation

Technique • A canthal-tragal line is drawn from the midpoint of the tragus to the

lateral canthus of the ipsilateral eye. • A point is made 10 mm forward from the tragus and 2 mm inferior to

the line. • This 10-2 point approximates the posterior extent of the articular

fossa. • This should be confirmed by palpation with the patient opening and

closing the mouth. • A second point corresponding to the height of the articular eminence

can be marked at  20 mm anterior to the midtragal point and 10 mm below the tragal-canrhal plane.

• This can function ‘as a land- mark for the placemernt of the second portal

• The superior joint is entered with an 18-gauge needle directed in an anterior-medial-inferior direction at the 10-2 entry point, aiming for the posterior aspect of the articular eminence or anterior recess.

• Once the joint space is entered, it may be insufflated with saline or lactated Ringer’s solution.

• Several milliliters solution can be injected rather passively into the joint space to the end point, where there is rebound of the syringe pressure with jaw movement.

• A second needle must be inserted for the outflow portal slightly anterior to the initial needle placement

• The lavage is performed by the surgeon using approximately 100 mL of fluid either manually or with intravenous fluid set-up.

• The joint can he manipulated by the assistant by protrusive and excursive movements.

• 40 mm of interincisal opening should be achieved after completion of arthrocentesis

• Inject steroids for their anti-inflammatory effects on the synovial tissue.

• Sodium hyaluronate has been proposed as a therapeutic agent in orthocentesis .

• It is a glycosarninoglycan produced by synovial cells and present in high concentrations in the joint cartilage and synovial fluid.

• This viscous, high molecular weight substance plays an important role in joint lubrication and protection of the cartilage.

• It has been demonstrated that arthrocentesis with the injection of sodium hyaluronate (a process called viscosupplementation) is an effective treatment 

• Contributes to joint function by lubrication, minimizing mechanical wear, and playing a role in the nutritional support of the avascular portion of disc and condylar cartilage

• Sever preoperative pain

• Relapse of maximal mouth opening

• Preoperative condylar deformation evident in MRI