The Treatment of Temporomandibular Joint Dislocation

Abstract

Background

The estimated incidence of temporomandibular joint dislocation in Germany is at least 25/100 000 per year. A correct diagnosis and the initiation of appropriate treatment without delay are essential if permanent damage to the joint is to be avoided.

Methods

This review is based on pertinent publications retrieved by a systematic search in the PubMed, Cochrane, Embase, and ZB Med databases.

Results

The initial search yielded 24 650 hits; duplicates were removed and 136 studies were chosen for further analysis. The diagnosis of temporomandibular joint dislocation is generally made clinically from the finding of a lower jaw that is fixed in the open position. Acute dislocations are manually repositioned at once. The most common method is Hippocratic repositioning, in which the physician’s thumb is placed laterally next to the teeth and the other fingers are placed on the lower surface of the lower jaw. The physician then exerts pressure, first caudally, then dorsally. Repositioning is carried out in two steps. For dislocations that have been present for a longer time, manual repositioning may be ineffective and surgery may be needed. Recurrent dislocation can be treated in a minimally invasive way with botulinum toxin injections or autologous blood therapy. Surgery may be needed if these methods are ineffective.

Conclusion

There have been no more than a few randomized, controlled trials of treatments for temporomandibular joint dislocation, in particular concerning minimally invasive and open surgical treatments, and therefore only limited evidence-based conclusions can be drawn. Nonetheless, the diagnostic and therapeutic standards that have been established in recent years have gained wide international acceptance.

Temporomandibular joint dislocation account for 3% of all documented dislocations. In Germany, its incidence is currently estimated to be at least 25 per 100 000 population each year (based on an e-mail survey by the German Society of Oral and Maxillofacial Surgery [DGMKG, Deutsche Gesellschaft für Mund-, Kiefer- und Gesichtschirurgie] conducted in 2017). Consequently, it is a condition as common as, for example, giant-cell arteritis. Although primarily affecting young adults, it may also occur in older people prone to temporomandibular joint dislocation (1, 2). Because of the associated painful limitation of joint mobility, patients experience temporomandibular joint dislocation and the resulting impairment of essential functions (speaking, chewing) as very distressing (1).

Besides neurological and neuromuscular diseases (3), advanced tooth loss with resulting lack of posterior support is regarded a predisposition for temporomandibular joint dislocation (4, 5). In an aging population, it is reasonable to expect a future rise in incidence (6). A significant number of unreported cases can already be assumed today. Especially in older patients with multimorbidity, symptoms tend to be less pronounced. Combined with a reduced ability to communicate their complaints, delayed diagnosis of dislocation is common, further complicating the management of patients in this group (5). Physicians not specialized in treating temporomandibular joint dislocation see only few patients with this dislocation. Consequently, they face the problem that they lack routine in the diagnosis and management of the condition. However, the earliest possible reduction is crucial since the longer the delay the more difficult it is to reduce the dislocation and the higher is the risk for recurrent dislocations (7– 9). These are associated with a significant negative effect on the quality of life of the affected patients and lead in the long term to subsequent damage to the temporomandibular joint (7).

Management is typically based on traditional surgical experiences which have been published on the level of established, but not evidence-based textbooks. More recent publications on the management of temporomandibular joint dislocation primarily originate from non-European/Anglo-American countries and their evidence level is frequently low (small case series, inhomogeneous endpoints, short follow-up). Thus, to optimize patient care, the aim of this clinical practice guideline is to describe a standardized and literature-based management approach to temporomandibular joint dislocation.

Methods

Search, selection and grading of scientific evidence

A literature search starting May 2014 was conducted in the databases PubMed, Cochrane, Embase, and ZBmed. The initial search of the English and German literature, starting 2000 and using the search term “temporomandibular joint dislocation“, identified 24 650 citations. In addition, the reference lists of the identified articles were screened for not yet included sources. The manual search also included older articles. Using the same search strategy, the sources were updated in August 2015 to take into account evidence from studies newly published while the clinical guideline was being created. Based on the selection criteria, altogether 136 papers were identified and summarized in tables (eFigure). Subsequent grading of the evidence was based on the criteria of the Oxford Centre for Evidence-based Medicine (eTable 1).

c) extraoral method of reduction

eTable 1. Criteria for evidence classification, grade of recommendation and consensus strength.

Level of evidence (LoE)	Study design
I	randomized controlled trial (RCT)
II	experimental study with control group (prospective)
III	retrospective cohort study, retrospective case-control study
IV	case series, animal experiment
V	case report, expert opinion
+	good quality* or sample size n>100
−	poor quality* or sample size n<10
a	meta-analysis or review article
b	single study
Grade of recommendation (GoR)	Description	Syntax
A	strong recommendation	shall
B	recommendation	should
0	recommendation open	may
Strength of consensus
strong consensus	>95% or participants
majority consensus	>75–95% of participants
consensus	50–75% of participants
no consensus	<50% of participants

* Quality criteria: disclosure of patient characteristics, no excessively strict exclusion criteria, precise description of diagnosis and management, as well as study analysis, internal (alternative explanations unlikely) and external validity (applicability of study results on the given decision context) of the results

Recommendations, structured consensus development, external review, and adoption

First, the draft guideline created based on the literature search was presented to the members of the Guideline Group Temporomandibular Joint Surgery of the DGMKG for structured consensus development. The draft was unanimously adopted as a proposal. The external professional societies involved in the interdisciplinary Delphi procedure and the adoption of the guideline are listed in eTable 2. On 30 June 2016, the AWMF published this clinical practice guideline online. Since then, 2 new studies on temporomandibular joint dislocation have become available. Since the evidence from the two studies supports the findings previously published in the literature, no revision of the guideline recommendations is currently required.

eTable 2. Participating professional societies.

Professional society	Acronym	Elected representative	E-mail
Deutsche Gesellschaft für Mund-, Kiefer- und Gesichtschirurgie (German Society of Oral and Maxillofacial Surgery)	DGMKG	Prof. Dr. med. Dr. med. dent. Andreas Neff (coordinator)	neffa@med.uni-marburg.de
Deutsche Gesellschaft für Prothetische Zahnmedizin und Biomaterialien e.V. (German Society of Prosthodontics and Biomaterials)	DGPro	Prof. Dr. med. dent. Peter Ottl	peter.ottl@med.uni-rostock.de
Deutsche Gesellschaft für Funktionsdiagnostik (German Society for Functional Diagnostics and Therapy)	DGFDT	PD. Dr. med. dent. M. Oliver Ahlers	oliver.ahlers@cmd-centrum.de
Deutscher Verband für Physiotherapie (The professional association of physiotherapists in Germany)	ZVK	Ima Feurer	info@ima-feurer.de

Definition and etiology

Temporomandibular joint dislocation of the non-fractured mandible most commonly involves bilateral dislocation of the mandibular heads anterior to the articular tubercles without spontaneous reduction (Figure 1) (10). Typically, younger adults between 25 and 45 years of age are affected (2, 11, 12).

Figure 1.

Anatomy of the temporomandibular joint

a) normal situation, b) anterior temporomandibular joint dislocation

The most common triggers are everyday activities associated with wide opening of the mouth, such as yawning, laughing or biting (1, 8, 13).

Iatrogenic triggers, such as anti-dopaminergic medication, intubation, endoscopic examinations, and prolonged dental treatments (e.g. tooth extractions) are less common (1, 8, 14). Here, dislocation is caused by prolonged and forced jaw opening in a patient with decreased muscle tone under medication (15). Therefore, patients should be asked prior to any surgical procedure to be performed under general anesthesia about any previous dislocations and risk factors for dislocation (grade of recommendation [GoR] B; levels of evidence [LoE] IV–V +) (14, 16). In addition, functional jaw mobility should be clinically checked before and after intubation to rule out temporomandibular joint dislocation (GoR B; LoE IV–V +) (14, 16). Predisposing risk factors include, among others, neurological and neuromuscular disorders (e.g. Parkinson’s disease, oromandibular dystonia), advanced tooth loss and congenital joint hyperlaxity (e.g. Marfan syndrome) (1, 3, 5). These factors cause a second incidence peak in older patients (5, 6).

Persistent mandibular dislocation has to be understood as the constant blockade of the mandibular condyle by the articular tubercle of the temporal bone and thus the long-term displacement of the mandibular condyle from the glenoid fossa. This leads to irreversible intra- and pericapsular changes (16, 17). From an accidental (acute, one-time) temporomandibular joint dislocation, recurrent temporomandibular joint dislocation may develop which involves recurrent, possibly fixed dislocations within a short period of time. Once this mechanism has been facilitated, it leads to habitual dislocations of the affected temporomandibular joint. At this point, dislocations can already occur during normal activities.

Diagnosis

Cardinal symptoms of temporomandibular joint dislocation are impaired occlusion/inability to close the jaws, and pain (1, 8). On clinical examination, an empty temporomandibular joint socket may be found and, in patients with long-term dislocation, signs of malnutrition (8). In patients under sedation, patients after trauma, patients with dementia and in patients with persistent dislocation, symptoms may be less noticeable so that the temporomandibular joint dislocation may initially be missed (1, 8, 14, 16).

Patients without acute facial trauma who for the first time experience a temporomandibular joint dislocation can be diagnosed based on medical history and physical examination alone, if the symptoms are sufficiently indicative of temporomandibular joint dislocation (GoR 0; LoE IIIa–V +) (8– 10, 18).

Imaging examinations (orthopantomogram [OPG], CBCT/DVT, MRI) should be performed in patients with symptoms allowing for other differential diagnoses, to rule out facial fractures and to provide information for further treatment planning (GoR B; LoE I–V +) (8, 10, 16, 19). Especially in older patients with multimorbidity, temporomandibular joint dislocation may initially be overlooked as symptoms are milder and the ability to communicate is often limited (5).

The treatment of acute temporomandibular joint dislocation

Every patient with non-traumatic temporomandibular joint dislocation should initially be treated with manual reduction (GoR B; LoE IIIa) (3). The earlier the reduction is performed the greater the chance of success (2, 9). The most commonly used technique is the Hippocratic method of reduction (8, 9, 20) (Figure 2a). According to more recent studies, the wrist pivot method represents an alternative manual technique for temporomandibular joint reduction which is at least equal to the Hippocratic method of reduction with regard to success rate, reduction-related pain and reduction time (9, 19, 21) (Figure 2b). Taking into account the risk of injury associated with this intraoral reduction technique, reduction may also be performed via the extraoral route in patients with unilateral dislocation (GoR 0; LoE I) (19) (Figure 2c). However, this technique is somewhat more painful and time-consuming compared to the described intraoral maneuvers (19).

a) Method of reduction according to Hippocrates (modified)

In patients with bilateral dislocation, the extraoral method has a low success rate (54.5% in patients with bilateral dislocation versus 96.7% in patients with unilateral dislocation) and its use is therefore only recommended in case of increased bite or infection risks (for example, in patients with dementia, hepatitis C patients) (19). Figure 3 provides a flow chart of an algorithm for the management of anterior temporomandibular joint dislocation. During reduction with the patient in a sitting position, the patient’s head should be stabilized using a headrest (GoR B; LoE IV–V +) (21, 22). When reduction is performed via the intraoral route, the use of bite blocks and gloves can help to prevent bite injuries and associated infections (GoR B; LoE V +to V) (21, 23).

b) Reduction using the wrist pivot method

According to the recommendation of the group of authors, attention should be paid that the fingers are placed not on, but lateral to the occlusal surfaces of the mandibular molars when using the modified Hippocratic technique (GoR B; LE V; expert consensus). In recent years, some studies presenting novel reduction methods have been published, but due to the small number of cases and the lack of control groups their statistical power is limited (13, 24, 25).

As a general rule it can be stated that the experience of the physician with the technique is key to the success of the reduction attempt and that the successful mobilization for reduction can be achieved with various maneuvers. Manual reduction of an acute dislocation can initially be attempted without administration of any medications (GoR 0; LoE IIIa–V +) (3, 7, 9, 20, 21). If the attempt is unsuccessful, further reduction attempts can be made under medication (muscle relaxants and/or analgesics) or, if required, under analgosedation or general anesthesia (GoR 0; LoE IIIa–V +) (3, 7, 9, 20, 21, 26).

The treatment of persistent temporomandibular joint dislocation

Approximately 30% of all temporomandibular joint dislocations presented to physicians are persistent dislocations (1, 3). Due to the low incidence of the condition, treatment recommendations are based on case series and case reports. If the dislocation has persisted for 3 to 4 weeks, manual reduction attempts are usually no longer successful. In this case, surgical reduction should be considered (GoR B; LoE I–V +) (1, 7, 20). Redressive methods (articular capsule opened for reduction) and more invasive techniques (eminectomy, condylectomy, special osteotomy techniques, endoprosthesis) are available for the surgical management of chronic dislocations (1, 7, 20).

The treatment of recurrent temporomandibular joint dislocation

The incidence of recurrence after initial dislocation is 22% according the literature (3). Minimally invasive techniques (botulinum toxin injection, autologous blood injection, prolotherapy) for the treatment of recurrent temporomandibular joint dislocation are primarily indicated in patients with reduced compliance or increased surgical risk (12). However, long-term outcomes are often not satisfactory and eventually invasive surgical management is required (8, 27– 29). Studies evaluating treatment with botulinum toxin injection include case series of up to 21 patients.

The available studies reported no further dislocations over a period of at least 5 months after single or multiple injections of botulinum toxin into the lateral pterygoid muscle (12, 30, 31).

However, treatment of recurrent temporomandibular joint dislocation with botulinum toxin is considered off-label use of the drug. Warnings of the manufacturers regarding the use of and indications for botulinum toxin should be observed (GoR A; LoE V; expert consensus). However, the authors of the guideline are of the opinion that the use of botulinum toxin to treat recurrent dislocations should be added as a new indication (GoR A; LoE V; expert consensus). Studies evaluating treatment with autologous blood comprise case series with up to 30 patients. It is assumed that injecting autologous blood into and around the temporomandibular joint will reduce the mobility of the articular head in the long term, thus preventing recurrent dislocations. In several case studies, the processes after autologous blood injection were followed up using MRI. Even though the postulated development of fibrosis was not confirmed—if it were, this would have to be viewed critically in case of excessive response—, it appears that temporomandibular joint mobility is restricted in the midterm so that the rate of recurrence of dislocation is reduced or the patient experiences no more recurrences at all. Yet, the exact underlying pathohistological mechanism remains unclear. Summarizing the larger studies of the last few years, approximately 80% of patients become symptom-free for the next 12 months. Aggravation of symptoms as a complication has not been reported (28, 32, 33). Similar assumptions as for treatment with autologous blood are made for prolotherapy (syn. sclerotherapy). Currently, a case series with 30 patients is available on this method in which 91% of patients experienced no recurrence of dislocation over a period of 6 months (18).

In patients with recurrent dislocations, an indication for open surgical treatment may be established after failure of conservative and/or minimally invasive methods (GoR 0; LoE IIIa–IV +) (28, 32). The most commonly used surgical techniques include eminectomy, blocking or sling procedures and surgery on the capsular ligament complex. Currently, eminectomy procedures are the best documented and most promising techniques among the various, to some extent competitive surgical methods (2, 27, 29).

Supplementary measures

In patients with persistent dislocations, reduction should be followed by immobilization to limit maximum opening of the mouth over a prolonged period of time (1 to 4 weeks) to prevent recurrence (GoR B; LoE IV–V) (7, 34). Bandages, head-chin cap or an elastic intermaxillary fixation (IMF) may be used for immobilization (1, 7). After surgery, regardless of the technique used, patients should for some days only eat soft food and avoid opening the mouth widely (GoR B; LoE IIb–V +) (6, 9, 18, 35– 37).

Furthermore, immobilization may be indicated especially after autologous blood injection and after surgery on the capsular ligament complex (GoR 0; LoE Ib–V) (28, 29, 33, 36, 37– 40). The goal is here to limit maximum opening of the jaws; rigid fixation should be avoided. In case of complicating further problems, such as malocclusion (for example, anterior open bite due to persistent dislocation refractory to treatment), an individualized approach based on the range of functional surgical procedures for temporomandibular joints as well as reconstructive and orthognathic surgery may be required (GoR 0; LoE IIIa–V) (3, 5, 20).

Conclusions

Due to small sample sizes and inhomogeneous study designs with often very short follow-up periods, there is a lack of reliable epidemiological data on the various treatment approaches. Consequently, higher-grade evidence-based recommendations can still not be issued and outcome analyses from research designed to provide high levels of evidence (randomized, controlled trials, meta-analyses) will not become available in the foreseeable future (8, 27). Nevertheless, in recent years some interventions with good success rates have been established as generally accepted standards on an international level.

The treatment of temporomandibular joint dislocation should be initiated as early as possible to limit degenerative changes or their progression—resulting from prolonged or recurrent dislocation or an increasing dislocation rate—and to enhance the chances of success of conservative/minimally invasive treatment methods (GoR B; LoE IIIa–V +) (1, 2, 7, 9).

Which treatment has the best chance of success is dependent on numerous factors, including pathogenesis, age of patient, secondary diagnoses, compliance, treatment goal, and care structures, among other. Thus, the best treatment for each individual patient should be determined based on a thorough medical history and physical examination (GoR B; LoE IIIa–IIIb -) (20, 35).

Figure 3.

Algorithm for acute anterior temporomandibular joint dislocation

Key Messages.

• Acute temporomandibular joint dislocation should immediately be manually reduced.

• The Hippocratic method of reduction and the wrist pivot method are considered to be equivalent. With both methods, the fingers should be placed lateral to the occlusal surfaces to prevent bite injuries.

• Given the risk of injury associated with intraoral reduction, extraoral reduction may be performed especially in infectious patients with unilateral dislocation. In patients with unilateral dislocation, the success rate of extraoral reduction is 96.7%.

• If the dislocation has persisted for 3 to 4 weeks, manual reduction attempts are usually no longer successful; in such cases, surgical reduction techniques are used.

• After the first temporomandibular joint dislocation, recurrence of dislocation is to be expected in about 20% of patients.

eFigure.

Literature search