-By Dr Saqba Alam
The disorders related to TMJ are so diverse that it makes the task challenging to describe each in a single transcript. An attempt has been made to define each with its management using literary evidence briefly. The article describes all TMJ pathosis in a nutshell.
We have broadly divided the most common joint pathologies as following.
A-Developmental pathologies
These include condylar hyperplasia, condylar hypoplasia and condylar resorption.
B-Acquired pathologies
a) Non-inflammatory degenerative pathology: Osteoarthritis
b) Pathology related to infection/inflammation: Capsulitis, synovitis, ankylosing spondylitis, rheumatoid arthritis and psoriatic arthritis
c) Structural abnormalities of joint: Disc displacement with and without reduction, joint dislocation, joint subluxation, disc degeneration and effusion
d)Growth abnormalities: Condylar hypoplasia, Hemi mandibular hyperplasia and Hemi mandibular elongation
e) Pathology related to micro or macro trauma: Condylar fractures affecting TMJ and Ankylosis from intracapsular haemorrhage organisation
f) Tumors: Benign and malignant tumours of TMJ/condyle
The above-simplified version of TMJ disorders does not define the TMJ pathologies as a whole. Still, it highlights the most commonly presented cases related to the Temporomandibular joints in dental and maxillofacial Out Patient Departments. This article aims to briefly discuss the diagnosis, management, and treatment of these commonly presented disorders of TMJ.
Diagnosing such disorders becomes a difficult mission for a clinician as the disease may mimic various other disorders and can have overlapping symptoms. Accurate diagnosis is thus crucial in managing such complex joint pathologies.
A general approach to the joint after a detailed history begins with the detection of asymmetry.
- Inspection: Inspection from both frontal and lateral views is important to pick any contour or size discrepancies, height disturbances and problems with the interarch relationship. Good intraoral and bite examination (Opening and Occlusion, Angles classification, skeletal classification, overjet/overbite). A TMJ patient needs to rule out interferences and causes for functional drifts. Such patients may also have a history of some form of parafunctional habit. Besides periodontal health, fractures and wear should also be assessed to have indirect effects on the joint.
- Palpation: TMJ palpation gives many clues for building up a good differential diagnosis. Palpation is performed at 10 or 11 o'clock positions. Joint tenderness, temperature, crepitus or inflammatory discharge or effusion needs to be evaluated with radiographic correlation. Mouth opening should be charted, and the joint is palpated for detection of pain and clicks in the opening, closing and lateral excursive and protrusive movements. Frank popping and rubbing sounds should also be noted either with or without the use of a stethoscope. At this point in the clinical examination, if the dentist is suspecting a structural deformity (after excluding all other causes of odontogenic pain), that usually is an Internal Derangements (most common 70%), the clinician should be able to classify the stage of Wilkes (Type 1-Type 5) and simultaneously try to elicit a Manhans’ sign to confirm the diagnosis which later can be radiologically verified. The jaw should open and close in a normal individual without deviation or deflection at least up to 40mm. The patient should be able to move the jaw laterally with teeth together up to 12mm each way and protrude till 10mm.
The extraoral examination includes examining the orofacial and cervical musculature. It requires palpating head and vertebral regions to diagnose referred pains like migraines or pain related to autoimmune conditions like rheumatoid arthritis. Neck mobility and rigidity should be taken into account. A neck flexion should be around 65-70 degrees, with a backward flexion until 40 degrees is normal. Left to right pain-free neck movement should approximately be around 85 degrees.
- Auscultation: Joint auscultation is an important part of physical examination to differentiate normal anatomy from abnormal. However, stethoscope auscultatory methods for TMJ have been questioned in the literature. In their study published in the Journal of Prosthetic dentistry, Casimir and Brian have suggested that the external auditory meatus (EAM) is the closest anatomically approachable structure to the TMJ. The auditory canal is more sensitive than the surface of the skin when evaluating joint sounds. They fabricated an instrument with a soft, disposable, sterile tip for auscultation of TMJ sounds in the EAM. Some electronic auscultatory devices have also shown superior results when compared with stethoscope auscultation.
Condylar hyperplasia
Postnatal growth abnormality of TMJ caused by continued hyperactivity of the mandibular condyle (after the closure of epiphyseal growth plates in long bones), resulting in progressive mandibular growth leading to jaw asymmetry over time.
Obwegeser, in 1986, classified jaw asymmetry as Hemi mandibular hyperplasia(vertical), Hemi mandibular elongation (horizontal)and a Hybrid variant.
Condylar hyperplasia is usually idiopathic. It has a progressive adolescent onset. Most cases are unilateral. Asymmetry happens later in the disease. However, the acquired abnormality can also occur secondary to trauma or infection due to excessive proliferation in the repair process, genetic factors, hypervascularity or increased functional loading of the joint.
Management options
- Symptomatic pain relief, wait for burnout/quiescent phase, then Orthognathic surgery
- Staged surgery, high condylar shave followed by orthognathic surgery
- Condylar shave with orthognathic surgery in one stage
- Total Mandibular Joint Replacement (TMJR)
Condylar resorption:
Progressive alteration in shape and size of the condyle due to idiopathic resorptions can be self-limiting. Resorption can be reactivated by joint loading, iatrogenically, after orthodontics or orthognathic surgeries. Some hormonal factors are also identified, linking the low estrogen levels associated with increased condylar resorption in females. Patients may complain of pain and intermittent locking.
These patients have a common facial morphology, including high occlusal and mandibular plane angles, progressively retruding mandible, and Class II occlusion with or without an open bite. Imaging usually demonstrates small resorbing condyles and TMJ articular disc dislocations.
Management options
The treatment can be conservative or invasive. Less invasive management for idiopathic condylar resorption comprises fabrication of splint to aid in pain relief and avoidance of unnecessary joint loading and deferment of orthodontic/orthognathic treatment until remission condylar resorption is vital. NSAIDs and other pharmacological therapy in conjunction play a role.
TMJ surgery for condylar resorption should include arthroscopy, joint lavage. Severe cases require open joint surgery and, lastly, alloplastic replacement in a stepwise manner. For cases that are not active, camouflage treatment with genioplasty and chin advancement may be the best choice with fewer complications postoperatively. However, Condylar resorption cases with anterior open bite should be managed with maxillary osteotomies.
Inflammatory joint conditions:
Managing inflammatory joint condition like arthritis or ankylosing spondylitis is a long, painstaking task. Still, a more or less same stepwise approach is required in treating all inflammatory conditions after a correct diagnosis has been made.
The common findings on an x-ray may include variable joint head erosions or flattening, osteopenia, joint effusion, or synovial thickening condition may be acute or chronic. A TMJ arthritis patient may have a normal x-ray but can be very symptomatic (pain, fever)or vice versa. Signs of inflammation may appear evident in acute cases and may be completely absent in chronic scenarios with malocclusion and “dull ache” as the only presenting complaint.
Management options
Rule out the cause (complete history, age, gender, and involvement of any other joints) examining TMJ as mentioned above. Investigations-Complete Blood Count, RA factor (for Rheumatoid Arthritis), Antinuclear Antibody, Erythrocyte Sedimentation Rate, C Reactive Protein.
- Step1-Medical Mx and Conservative options: Reassure, jaw rest, soft diet, avoidance of wide mouth opening, physiotherapy, NSAIDs, soft splints. For autoimmune joint diseases, DMARDS, low dose Tricyclic Antidepressants (TCAs) for chronic pain can be considered.
- Step 2-Pain relief using Anesthesia: Arthroscopy and Arthrocentesis(upper joint cavity), joint lavage, long-acting Bupivacaine intraarticular or periarticular injections for pain relief.
- Step 3- Open Joint Surgery: After 3D planning, MRI, Arthroscopy and definite evidence of degenerating disease. When step 1 and step 2 do not give effective results or the patient’s pain scores, remain 4 and above, consider open joint surgery (minimal invasive to invasive):- synovectomy, adhesiolysis, eminoplasty, eminectomy, disc plication, discectomy, condylar shave.
- Step 4-Recurrence or previously operated cases with higher pain scores: Consider Total Joint Replacement with Alloplastic devices.
Non-inflammatory osteoarthritis and degenerative joint disease
TMJ osteoarthritis is a degenerative joint disease with varying degrees of inflammation and destruction of the articular cartilage and subchondral bone resorption. It is more prevalent in women and the elderly. The degenerative changes are more frequent in the mandibular condyle than in the mandibular fossa or the articular eminence, and the characteristic pathological bony changes are erosion, osteophytes, and deformity. Adaptive bony changes are marginal proliferation, flattening, concavity, sclerosis, and subchondral cyst. Such conditions are diagnosed using conventional CT, CBCT and sometimes bone scintigraphy. One or more degenerative changes can be found in a single individual example, osteoarthritis with joint effusion or osteoarthritis with internal derangement and pain.
Management options
The management options include invasive surgical procedures, less invasive surgical procedures and conservative methods of treatment.
Internal derangements
Structural deformities of the meniscus or disc are known as internal disc derangements. Wilkes staging system classifies these deranged discs into five types, with 5 being the most severe needing a prosthetic replacement of the joint itself. If the disc remains anterior to the condyle, it is said to be a derangement without reduction. At any point during movement, the disc returns to the head of the condyle; it is called a disc derangement with reduction. The challenge for clinicians is to diagnose the exact condition that causes the disc derangements. Once identified, the basis for the treatment is to relieve the patient’s symptoms and improve healing while simultaneously removing the causal factors. The following causal should be addressed carefully: excessive joint loading (increased joint friction disrupts the cartilage metabolism leading to sequelae of disc deformity), trauma, systemic and localised arthropathies.
Management options
Usually a click or a popping sound is heard during the early opening or late closure of the rotational/translational cycle. That is when a patient with disc derangement benefits most from conservative therapies of pain relief such as splint fabrication. Late Wilkes stages (2,3,4) may require arthroscopy and joint lavage via arthrocentesis. Stage 4 and 5 Wilkes’ may require the clinician to opt for open joint procedures such as meniscus repair, repositioning and replacement and use of alloplastic prosthesis. However, Ufuk Tatli and Vladimir Machon, in their article published in 2016, suggested that conservative and surgical treatments should never be considered separately. The two therapeutic options should always be taken into account, and that the failure to identify and control the causal factors such as joint overload usually results in treatment failure.
Discs can be displaced in any direction; however, anterior disc derangements are most commonly presented.
Joint hypermobility –Subluxation and luxation:
A temporomandibular joint dislocation occurs when the disc remains in the anterior position to the eminence and does not retract, thereby pulling the retrodiscal pad being pulled between the two bony surfaces of the condyle and the temporal bone. This laxity of the disc and spasm in the lateral pterygoids results from imbalances either in the neuromuscular dysfunction(central cause)or structural deficits (local causes). The hypermobility of the joint can be acute or chronic, partial or self-reducible (subluxation) and complete (luxation)or difficult to reduce by the patient. Predisposing factors leading to capsular laxity and weaker ligaments include local trauma altering joint anatomy and atypical disc position or neurodegenerative disorders like Parkinson's’, multiple sclerosis and epilepsy. Some connective tissue disorders like Ehler danlos syndrome can result in joint dislocations. Iatrogenic causes include intubation, long-standing dental treatment like Root canal treatments where the patient must open the jaw for long periods.
Unlike TMJ subluxation (partially dislocated), in the case of TMJ luxation (complete dislocation), condyles are unable to self return to the fossa without the help of a clinician to manoeuvre the jaw back into a normal position. The most common clinical symptom is the inability to close the oral cavity, i.e., ‘open lock,’ difficulty in speech, drooling of saliva, and lip incompetency. There is a pain in the pre auricular region in acute cases, but patients are usually asymptomatic in chronic recurrent dislocations. Dislocations are usually bilateral, but unilateral dislocation may lead to deviation of the chin to the contralateral side. Palpation over the preauricular region may suggest emptiness in the joint space.
Management options
Management of acute cases differs greatly from both chronic and recurrent dislocations.
Akinbami classified TMJ dislocation into the following three types:
- Type I - the head of the condyle is directly below the tip of the eminence
- Type II - the head of the condyle is in front of the tip of the eminence
- Type III - the head of the condyle is high-up in front of the base of the eminence
Acute dislocations are quite painful but are easy to manage. Many different manoeuvres are described in the literature. The clinician uses manual reduction under local anaesthesia or via auriculotemporal nerve blocks using the downward, backward and upward Hippocrates method and many others, including gag reflex by probing the soft palate, creating a reflex neuromuscular action causing reduction.
Chronic dislocations, however, are difficult to manage and reduce back into the fossa. Chronic persistent dislocation can be defined as acute dislocation left untreated or inadequately treated for 72 hours or more. There is consensus that if the situation persists for more than a month, it is labelled as long-standing or protracted temporomandibular joint dislocation. This last condition is the most challenging and difficult to treat of the three. Dislocations persisting for more than four weeks are usually unable to reduce with secure methods, and an open joint reduction becomes necessary. These open procedures include eminectomy, meniscectomy, myotomy or condylotomy.
For recurrent cases, several surgical procedures for creating an obstacle at the eminence have been suggested for limiting the anterior movement of the condylar head to hinder recurrent TMJ luxation. Examples are down fracture of the zygomatic arch, also known as Daltrey's procedure, bone grafting, myotomy of lateral pterygoids, muscle or tendon scarifications. Botox and sclerotherapy also play an effective role.
Trauma:
Condylar fractures roughly account for 20-25% of all mandibular fractures. Any injury to the condyle itself affects the TMJ unit as a whole. Facial asymmetry, malocclusion, disturbances in growth, osteoarthritis, and ankylosis can manifest as complications from trauma to the TMJ or secondary post-traumatic injury.
Temporomandibular joint ankylosis secondary to condylar fractures results as sequelae after displacement of the detached condylar stump laterally or superolateral concerning the zygomatic arch where it fuses. The organisation of the blood clot leads to calcification and obliteration of joint space. Treatment goals for all traumatic cases remain the same: achievement of pre-traumatic function, the establishment of the vertical height of the lower face, restoration of facial symmetry, and resolution of pain.
In cases of ankylosis, complete resection of ankylotic chunk followed by reconstruction of whole Ramal Condylar Unit via autogenous (allowing dynamic growth)Costochondral Rib/metatarsal/Sternoclavicular/calvarial or alloplastic -distraction/ (TMJR) means remain the gold standard.
Condylar fracture treatments can be grouped into closed methods (intermaxillary fixation using wires/screws/elastics and open procedures (Open Reduction and Internal Fixation-ORIF).
The choice of surgical or non-surgical treatment of mandibular condylar fractures remains controversial.
Tumours:
Tumours (true neoplasms)and pseudotumours (osteochondromas, synovial chondromatosis, pigmented villonodular synovitis and eosinophilic granuloma ) of the Temporomandibular joint are extremely rare. According to a study published in 2013 by Rafael et al., only 285 TMJ tumours are published in 15 journals covering 20 years. They found that the most frequent lesions were pseudotumours. Clinical manifestations were pain, swelling and the limitation of joint movements. The most common radiological findings for both benign and malignant lesions were radiopacities and radiotransparencies.
Management of such lesions is therefore controversial due to the paucity of literature. However, true malignancies should be treated using the same protocol for other maxillofacial neoplasms.
-The author is an oral and maxillofacial FCPS finalist. She has completed her residency at Abbasi Shaheed hospital, Karachi and has worked as an intern at various renowned hospitals. She has national and international internship experiences as a dental student and has also worked as an observer at an NHS private practice in the UK. She has been working as a Registrar at Altamash Medical Hospital and currently working at an esthetic clinic and can be reached at drsaqbaalam@gmail.com
