Temporomandibular joint ankylosis caused by condylar fractures: a retrospective analysis of cases at an urban teaching hospital in Nigeria

Abstract

Mandibular condylar fractures are common presentations to hospitals across the globe and remain the most important cause of temporomandibular joint (TMJ) ankylosis. This study aimed to analyze cases of mandibular condylar fracture complicated by TMJ ankylosis after treatment. A 16-year retrospective analysis was performed at the dental and maxillofacial surgery clinic of the study institution; patient data were collected from the hospital records and entered into a pro-forma questionnaire. It was found that 56/3596 (1.6%) fractures resulted in TMJ ankylosis. The age of patients with ankylosis ranged from 12 to 47 years. The age ( P = 0.03) and gender ( P = 0.01) distributions were significant, with most cases of ankylosis occurring in those aged 11–30 years ( n = 43/56, 76.8%). Fractures complicated by ankylosis were intracapsular ( n = 22/56, 39.3%) and extracapsular ( n = 34/56, 60.7%). Ankylosis increased significantly with the increase in time lag between injury and fracture treatment ( P = 0.001). Ankylosis was associated with concomitant mandibular (85.7%) and middle third (66.1%) fractures. Treatment methods were not significantly related to ankylosis ( P = 0.32). All cases of ankylosis were unilateral, and complete ( n = 36, 64.3%) and incomplete ankylosis ( n = 20, 35.7%) were diagnosed clinically. The incorporation of computed tomography scans and rigid internal fixation in the management of condylar fractures will reduce ankylosis.

Temporomandibular joint (TMJ) ankylosis is a debilitating condition and most often has an adverse effect on quality of life in those afflicted, as it results in impaired mastication, digestion, speech, appearance, and oral hygiene. It is a challenging clinical and social problem, and often starts during the active growth stage of early childhood. From a surgical perspective, ankylosis is not only challenging to treat technically, but in children, the surgeon must also consider the potential effects of time and growth on the outcome of the procedure.

When compared with other aetiologies, the condition is most commonly associated with trauma (13–100%), particularly to the mandibular condyle; fractures of the mandibular condyle constitute 25–35% of all mandibular fractures. As a result of an improved understanding of the management of condylar fractures, the incidence is decreasing in developed countries, but it is still relatively high in most third world countries, particularly Nigeria where confounding variables associated with the management of these fractures adversely affect treatment outcomes.

Consequently, because mandibular fractures are a common occurrence, mandibular condylar fractures are frequent presentations to hospitals across the globe and remain the most important cause or predisposing factor to the development of TMJ ankylosis. From the existing literature, several studies have reviewed various aspects of TMJ ankylosis with more emphasis placed on treatment, but few have evaluated the role played by mandibular condylar fractures and the resulting consequences in the propagation of this condition. Therefore, for the improved management of condylar fractures and prevention of TMJ ankylosis due to condylar fracture, the consequences of these fractures were examined retrospectively, for a 16-year period, in a tertiary hospital in Nigeria.

Materials and methods

This was a retrospective study of patients who sustained fractures of the mandibular condyle that were complicated by TMJ ankylosis after treatment was undertaken. The subjects presented to the oral and maxillofacial surgery clinic of the study institution in Calabar, Nigeria, between June 1996 and May 2012. The study was exempted from ethical clearance by the research and ethics committee of the institution.

Cases with complete data were included in the study, whereas cases with incomplete data were excluded. The condylar fractures studied were categorized based on the classification of Marker et al., with the following modification: condylar head and neck fractures were classified as intracapsular, while those below the neck were classified as extracapsular or subcondylar. The types of radiographic images utilized to classify fractures were postero-anterior (PA) of the jaws or skull, two oblique laterals of the mandible, and Towne’s view (axial). The radiographs were certified as standardized by the Association of Radiologists in Nigeria (Calabar branch). The images were evaluated by three examiners: an oral and maxillofacial surgeon who regularly deals with trauma, a senior resident in oral and maxillofacial surgery traumatology, and a traumatology radiologist. For the diagnosis of condylar fractures, the examiners were given three options to choose from: (1) fracture, (2) no fracture, and (3) uncertain.

The criteria for the diagnosis of TMJ ankylosis were the absence of protrusive movement on the involved side and the presence of bony consolidation in the region of the TMJ on postero-anterior skull, lateral oblique mandible, and TMJ radiographic views (transcranial). The ankylosis that presented was further categorized as follows: (1) Complete: restricted mouth opening with maximum inter-incisal distance of <0.5 cm; absence of palpable movements or complete immobility of the joints. (2) Incomplete: restricted mouth opening, but with a maximum inter-incisal distance of ≥0.5 cm; partial mobility of the joints on palpation.

Although computed tomography (CT) and magnetic resonance imaging (MRI) are the gold standards in the radiological diagnosis of mandibular condylar fractures and TMJ ankylosis, non-availability and unaffordability for the patient precluded their routine use for the diagnosis of condylar fractures and TMJ ankylosis in the study institution during the period studied.

Information obtained from the hospital register, case files, and plain radiographs of the subjects were recorded in a pro-forma questionnaire. The information recorded were age, gender, type of condylar fracture, displacement or no displacement of the fractured condylar fragment, and the presence of concomitant mandibular and midfacial fractures. Other factors considered were the time lag between injury and treatment of the fracture, methods of fracture treatment, and types of ankylosis that developed. The data obtained were analyzed using Epi Info 7, 2012 software (US Centers for Disease Control and Prevention, Atlanta, GA, USA). For analysis, simple frequency charts, descriptive statistics, and tests of significance were used. P -values of <0.05 were considered significant.

Results

A total of 3337 patients with 3596 condylar fractures were included in this study, and 56/3596 (1.6%) fractures were complicated by TMJ ankylosis after treatment. The age and gender distributions of the patients are shown in Fig. 1 . There were 41 males and 15 females, giving a male to female ratio of 2.7:1. The males outnumbered the females in all age categories. The gender ( P = 0.01) and age ( P = 0.03) distributions were significant. The age of patients with TMJ ankylosis ranged from 12 to 47 years (mean 31.4 ± 2.3 years). More cases of ankylosis was recorded in those aged 11–30 years ( n = 43/56, 76.8%) compared to those aged 31–50 years ( n = 13/56, 23.2%).

Fig. 1
Age and gender distributions of patients with TMJ ankylosis (age: χ 2 = 147.376, df = 8, P = 0.03; gender: χ 2 = 147.376, df = 8, P = 0.01).

Road traffic accidents (RTA) were the major ( n = 49/56, 87.5%) cause of fractures that resulted in ankylosis, while assault was the cause in the remainder ( n = 7/56, 12.5%). The types of condylar fracture involved were intracapsular ( n = 22/56, 39.3%) and extracapsular or subcondylar ( n = 34/56, 60.7%). The number of TMJ ankylosis cases increased with the increasing time lag between injury and fracture treatment, and this was significant ( P = 0.001) ( Fig. 2 ).

Fig. 2
Time lag in weeks between injury and treatment of condylar fractures ( χ 2 = 206, df = 12, P = 0.001).

The distribution of ankylosis according to the types of condylar fracture and concomitant mandibular fractures are shown in Table 1 . Those with intracapsular fractures and displaced condylar segments were found to be more prone to ankylosis than those with extracapsular (subcondylar) and undisplaced fractures. Of those with ankylosis, this was associated with concomitant mandibular fractures in 85.7% (48/56); 14.3% (8/56) had no concomitant mandibular fractures. Symphysis/angle and symphysis/parasymphysis/body fracture combinations resulted in more ankylosis than the other concomitant mandibular fracture combinations.

Table 1
fractures of the mandible.
Type of fracture No ankylosis Ankylosis Total
Number % Number % Number %
Site
Intracapsular 568 96.3 22 3.7 590 100
Extracapsular 2613 98.7 34 1.3 2647 100
Displacement of fragment
Displacement 1561 97.4 41 2.6 1602 100
No displacement 1720 99.1 15 0.9 1735 100
Concomitant fracture
Not present 462 98.3 8 1.7 470 100
Present 2819 98.3 48 1.7 2867 100
Distribution of concomitant fractures
Symphysis/angle 463 16.2 13 0.4 476 16.6
Symphysis/parasymphysis/body 503 17.5 11 0.4 514 17.9
Symphysis/body/angle 312 10.9 8 0.3 320 11.2
Parasymphysis/body 327 11.4 6 0.2 333 11.6
Symphysis/body 385 13.4 3 0.1 388 13.5
Angle 182 6.4 2 0.1 184 6.5
Symphysis 109 3.8 3 0.1 112 3.9
Angle/body 78 2.7 1 0.1 79 2.8
Body 236 8.2 1 0.0 237 8.2
Parasymphysis/angle 224 7.8 1 0.0 225 7.8
Total 2819 98.3 48 1.7 2867 100

Table 2 shows the distribution of ankylosis according to concomitant fractures of the midfacial bones. Thirty-seven of the 56 cases (66.1%) had these concomitant fractures associated with TMJ ankylosis; 19/56 (33.9%) cases occurred without their involvement. Furthermore, a greater number of subjects were recorded with fracture combinations of Le Fort I, II, III, nasal ( n = 6/37, 0.3%) and Le Fort II, III, nasal ( n = 6/37, 0.3%).

Table 2
Distribution of TMJ ankylosis according to concomitant fractures of the middle third of the facial bones.
No ankylosis Ankylosis Total
Number % Number % Number %
Concomitant fracture
Not present 1549 98.8 19 1.2 1568 100
Present 1732 97.9 37 2.1 1769 100
Distribution of concomitant fractures
Type of fracture
Le Fort I, II, III, nasal 195 11.0 6 0.3 201 11.4
Le Fort II, III, nasal 188 10.6 6 0.3 194 11
Le Fort I, II, zygomatic complex 166 9.4 5 0.3 171 9.7
Le Fort I, II, III 104 5.9 5 0.3 109 6.2
Zygomatic complex 172 9.7 4 0.2 176 9.9
Le Fort I, II 293 16.6 3 0.2 296 16.7
Le Fort I, II, nasal 219 12.4 3 0.2 222 12.5
Le Fort I 321 18.1 2 0.1 323 18.2
Zygomatic arch 26 1.5 2 0.1 28 1.6
Nasal 48 2.7 1 0.1 49 2.8
Total 1732 97.9 37 2.1 1769 100
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Jan 17, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Temporomandibular joint ankylosis caused by condylar fractures: a retrospective analysis of cases at an urban teaching hospital in Nigeria
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