Key points
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Mandibular trauma with or without condylar fractures can affect the temporomandibular joint.
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Almost all condylar fractures in children and most of them in adults can be managed with closed reduction with acceptable outcomes.
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Recent data report better functional outcomes with open treatment of condylar fractures and concomitant soft tissue repair but at a low risk of facial nerve injury.
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Severely displaced condylar fractures may be associated with soft tissue injuries that are in need of soft tissue repair.
Introduction
Maxillofacial trauma involves the mandible up to 50% of the time. Condylar fractures constitute 10% to 40% of mandibular fractures. Much of the literature on management of condylar fractures historically focused on treating the bony injury with closed or open approaches, overlooking soft tissue injuries within the temporomandibular joint (TMJ). Available data support closed treatment of almost all condylar fractures in children younger than 12 years because of their excellent remodeling capacity. Treatment of condylar fractures in adults remains controversial between proponents of open treatment versus closed treatment, with open treatment recently gaining more acceptance. Recent studies based on MRI and arthroscopy show objective evidence of injury to the capsule, meniscus, and ligaments in and around the TMJ. Based on these studies, we now know that mandibular trauma with or without fractures can be associated with injury to the soft and hard tissues of the TMJ. Improved long-term outcomes have been reported by some prospective studies with simultaneous soft tissue repair during open treatment of certain types of condylar fractures as opposed to closed treatment. Further knowledge on the role of soft tissue injury in healing of condylar fracture may pave the way for a major change in treatment protocols in the future. The current article focuses on treatment of injury to the TMJ region as a combination of soft tissue injury and condylar fractures.
Incidence and presentation of temporomandibular joint trauma
A recent 5-year data review by Alfrooz and colleagues in 2015 from the National Trauma Data Base (NTDB) with 13,142 patients found that condylar and subcondylar fractures constituted 14.8% and 12.6% of all mandibular fractures, respectively, in the United States. In the same study, the mechanism of injury most commonly causing condylar fractures were motor vehicle accidents and assaults. A traumatic injury that can result in mandibular trauma presumably also can cause direct or indirect TMJ trauma. MRI and arthroscopy studies have shown evidence of trauma to the soft tissues within the TMJ even without radiographic evidence of condylar fractures. Trauma to the TMJ with or without condylar fractures commonly manifests with facial swelling, malocclusion, and limitation in mandibular range of motion. The preauricular region may elicit ecchymosis and/or tenderness to palpation. In patients with displaced unilateral condylar or subcondylar fractures, occlusal examination may show premature contact on the ipsilateral side secondary to loss of ramus height with open bite on the anterior and contralateral posterior dentition. Patients who have hemarthrosis without a fracture in the condylar region may show open bite on the side of the injury ( Fig. 1 A, B ). Limited mandibular range of motion is consistent with injury to the muscles of mastication, with limited lateral excursions in the direction away from the side of fracture in unilateral cases. Bilateral condylar fractures commonly present with an anterior open bite with premature posterior contact ( Fig. 1 C). Presence of concomitant facial fractures in the rest of the maxillofacial region may mask or change the signs of malocclusion ( Fig. 1 D).
Initial radiographic evaluation of maxillofacial trauma at most modern medical centers consists of orthopantomogram/plain skull films with or without computed tomography (CT) scans. CT scan evaluation is considered the gold standard in the diagnosis of maxillofacial fractures. Although CT scans may not be the best imaging to assess soft tissue structures, hemarthrosis or fluid buildup is often noted on CT scan, evident by an increase in the joint space (see Fig. 1 A). Although MRI scan is not standard of care in facial fractures and may not be feasible in an acute trauma setting, it is a reliable technique to assess soft tissues in the TMJ. Several investigators have studied acutely injured TMJs with MRI scans to assess the extent of soft tissue injuries. These studies show a high incidence of hemarthrosis, capsular tear, disc displacement, and perforation of the disc or bilaminar tissues ( Fig. 2 ). Patients who sustain severe condylar displacement show much worse soft tissue injuries. It is also found that the cases without bony fracture in the condyle also sustain significantly more injury than the ones that have evidence of condylar fractures, perhaps due to the amount of force transferred to the soft tissues. Arthroscopic studies showed hemarthrosis in the superior joint space in all cases of condylar injury, and in approximately 60% of the inferior joint spaces in patients with mandibular trauma with or without evidence of fracture.
Classification of temporomandibular joint trauma
Several classification systems involving the condylar fractures have been described over the past century, but none has been universally accepted. The varying nomenclature for types of condylar fractures has made this more challenging. A comprehensive classification system proposed by Lindahl is based on level of the bony fracture, dislocation of the fractured segment, and its relationship to the articular fossa. The level of fractures was classified into condylar head, neck, and subcondylar types ( Fig. 3 ). Although this classification is comprehensive, it is complex for practical application and does not involve possible treatment. A newer classification system proposed by Bhagol and colleagues for subcondylar fractures based on 2 known predictable variations that determine the type of treatment, including the degree of displacement and amount of reduction in ramus height, was validated with a prospective clinical study. Subcondylar fractures were classified into minimally displaced, moderately displaced, and severely displaced, and correlated with increasing loss of ramus height. Class I fractures are minimally displaced fractures and are treated closed, whereas class II fractures can be treated with open or closed and class III fractures are treated with open reduction. Unfortunately, none of the current classification systems include soft tissue injuries. Hence, the treating surgeon should consider trauma on a case-by-case basis considering type of condylar fractures, concomitant fractures, injury to the TMJ soft tissues, risk to the facial nerve, and patient-specific variables that prevent open or closed treatment.
Management of temporomandibular joint trauma
Bony injury
Bony components of the TMJ include the condyle, eminence, and the glenoid fossa. Condylar fractures are commonly seen bony injuries in TMJ trauma with varying levels of displacement and resultant loss of ramus height. Glenoid fossa fractures are fortunately less common and could result in displacement of the condyle into the middle cranial fossa.
Condylar fractures
Up to 70% of condylar fractures, in general, are found to be associated with concomitant mandibular fractures in other regions of the mandible, most commonly the parasymphysis and body. Conventionally, condylar fractures have been treated with closed treatment approaches involving varying periods of immobilization of the jaws with maxillomandibular fixation (MMF) ranging from 2 to 6 weeks. MMF is performed with using arch bars and wires or MMF screws and wires or hybrid arch bars that are secured with screws interdentally ( Fig. 4 ). Closed treatment technique is easier, quicker, associated with fewer surgical risks, and does not require a steep learning curve that may be required for open treatment. Closed treatment of condylar fractures is based on the ability of the teeth, soft tissue, and bone in the condyles to adapt to the new position and still maintain form and function. Almost all condylar fractures in children can be treated with closed treatment due to the capability of bone to remodel over the growth years. In adults, nondisplaced or minimally displaced condylar or subcondylar fractures can be managed with short-term immobilization using maxillomandibular fixation for 1 to 2 weeks followed by rehabilitation using jaw exercises and guiding elastics to maintain occlusion.
Open treatment versus closed treatment of condylar fractures
Closed treatment of condylar fractures in adults has been the mainstay for several decades. Although easier to perform and associated with fewer surgical risks, closed treatment has been shown to result in increased mandibular deviation, increased risk of malocclusion, and minimal anatomic changes in the displaced bone and soft tissues of the TMJ. Overall, the results from treatment of condylar fractures with closed treatment have been acceptable, if not ideal. The patient’s medical comorbidities and expectations always should be considered when choosing between open versus closed treatment in any type of condylar fracture. A proper informed consent with discussion of treatment options, risks involved, and patient expectations and their capability to handle MMF is crucial to make the correct decision. In 1983, Zide and Kent recommended absolute and relative indications for open treatment of condylar fractures, but the absolute indications are rare and relative indications are difficult to justify in all cases.
Multiple prospective randomized studies have shown acceptable outcomes with closed treatment while showing improved functionality with open treatment. A recent systematic review with meta-analysis comparing open versus closed treatment for condylar fractures by Al Morriasi and Ellis showed superiority of open treatment with regard to maximal mouth opening, malocclusion, lateral excursions, chin deviation, pain, and asymmetry. But some of the drawbacks of this systematic review were the inability to differentiate the types of fractures among the studies included, inclusion of bilateral condyle fractures with unilateral fractures, and variability and bias in the studies.
Open treatment of condylar fractures is gaining preference lately, with increasing knowledge of improved outcomes as well as improved fixation techniques. Open treatment provides the advantage of early function, better anatomic correction of displaced condyles, and the opportunity to assess and repair soft tissue injuries. It carries the risk of facial nerve injury and scar formation. Based on the level of condylar fracture, extraoral or intraoral surgical approaches to perform open reduction and internal fixation can be used. Extraoral approaches may include the preauricular approach, retroauricular approach, and retromandibular and submandibular approaches. Modification of these conventional approaches also has been described, such as the transmasseteric approach ( Fig. 5 ). Intraoral approaches with or without endoscopic assistance have been described to reduce the chance of facial nerve injury. Studies on surgical complications from open treatment of condylar fractures report a high incidence of transient facial nerve weakness but low incidence of permanent facial nerve injury. Endoscopic approaches also are reported to have an incidence of transient facial nerve injury. Because of the steep learning curve, special equipment required, and prolonged duration of the operation, endoscopic repair of condylar fracture has fallen out of favor. Other rare potential complications from open treatment of condylar fractures, although rare, include Frey syndrome, sialocele formation, infections, resorption of the condyle, and failure of hardware. Although open treatment may have better functional outcomes, surgical risks should be weighed against the benefits. Several factors should be considered before using an open approach, including type/location of fracture, displacement of the condyle, the patient’s ability to undergo surgery from a medical standpoint, the surgeon’s expertise with open approaches, risk for scar formation, and facial nerve injury.
