This study analysed the relationship between complaints and mandibular function after closed treatment of fractures of the mandibular condyle in a prospective study. In a 1-year follow-up, complaints were assessed during physical examination and function was assessed using the mandibular function impairment questionnaire (MFIQ), scoring range 0–68. Data from 114 patients (41 women, 73 men), mean age 28.1 years (SD 13.3), were available. On average the MFIQ scores were low 3.4 (SD 7.3). Ten patients (9%) experienced pain and 45 (39%) patients had a MFIQ score > 0. Mean mouth opening was 51.9 mm (SD 8.4). Occlusion was perceived as moderate or poor by 24% of the patients. In the logistic regression analysis mandibular function impairment (MFIQ score > 0) was entered as a dependent variable. Risk factors for mandibular function impairment were: pain, perceived occlusion (moderate or poor), absolute difference between left and right horizontal movements and age. A protective factor was mouth opening. The results of this study show that complaints (i.e. pain, perceived occlusion, reduced mouth opening, difference between left and right lateral movements and increased age) are predictors of mandibular function impairment after closed treatment of fractures of the mandibular condyle.
Fractures of the mandible are the most common maxillofacial fractures (57%) . Of the maxillofacial fractures acquired while playing sports, about one-third are mandibular fractures . Fractures of the mandibular condyle represent 18–57% of all mandibular fractures . The most common cause of a fracture of the mandibular condyle is a traffic accident. Other causes are assault, stumbling, sports accidents, falls from heights, and industrial accidents .
The clinical features of a fracture of the mandibular condyle include malocclusion, open bite, swelling and tenderness over the joint, loss of mandibular function, deviation of the chin, crepitus and laceration of the skin .
Treatment options for fractures of the mandibular condyle are open reduction with internal fixation, and closed treatment . An endoscopically assisted intraoral approach with open reduction and internal fixation is becoming popular and these procedures show promising results .
Treatment of a fracture of the mandibular condyle depends on clinical and radiological evidence for the presence of the fracture, extent of the injury (unilateral or bilateral), level of the fracture, degree of displacement or dislocation, presence of additional facial fractures, dental malocclusion and mandibular dysfunction, posterior occlusal support, clinical experience of the surgeon and willingness of the patient to undergo surgery .
Complications resulting from a condylar fracture and its treatment include malocclusion, loss of ramus height, and related facial and or mandibular asymmetry, ankylosis (in 0.2–0.4% of the condylar fractures), anterior open bite, chronic pain, joint pain, reduced mandibular function, crepitation, hypomobility (8–10%), deviation on mouth opening, and facial nerve injury .
Recently in a prospective cohort study, perceived mandibular function and pain after closed treatment of fractures of the mandibular condyle was studied in a 1-year follow-up. It was found that the most important risk factor for pain persisting for 1 year after closed treatment is being a woman. The most important risk factors for functional impairment are an age over 25 years and gross displacement of the fracture parts .
The relationship between complaints assessed at 1-year follow-up and mandibular function was not reported in that study. Insight into that relationship may aid in prioritizing treatment of long term complaints after fractures of the mandibular condyle in order to improve mandibular functioning.
The aim of this study was to analyse the relationship between complaints after closed treatment of fractures of the mandibular condyle and mandibular function impairment in a prospective cohort study.
Materials and methods
Patients who were referred with a fracture of the mandibular condyle between March 1998 and July 2002 were asked to participate in this study. Inclusion criteria were fracture of the mandibular condyle less than 1 week old demonstrated on roentgenograms or CT scan. Exclusion criteria were a history of psychiatric disorders or mental retardation, the inability to understand Dutch, and impairment of mandibular function or pain in the temporomandibular joint or the muscles of mastication prior to fracturing the mandibular condyle.
Fracture type and the position of the fracture segments were assessed on roentgenogram by a senior staff member. The fracture types distinguished were intracapsular and extracapsular. Fracture segment position was scored as dislocation of the condylar head (yes or no), displacement (none, minor or gross) and deviation of the fracture segment (yes or no).
Previously the following criteria were defined: ‘Fracture segments were considered displaced when the proximal segment of the fracture was displaced relative to the distal segment and no overlap between the segments was present. The displacement was assessed as grossly displaced, or not or minor displaced. The fracture segments were considered deviated if the proximal segment and the distal segment made contact and there was angulation between the segments.’
Treatment of the fractured mandibular condyles was performed according to the standard procedures of the department. If the patient could reach maximal occlusion or occlusion was only minimally disturbed, no active treatment was provided. The patient was instructed to contact the department if occlusion deteriorated or if complaints increased.
If occlusion deteriorated and the patient could not reach maximal occlusion, arch bars with guiding elastics were inserted the day the patient was first seen (usually the day of the accident or the day after) for 2–3 weeks. Standard arch bars were inserted and guiding elastics were given if the posttraumatic open bite was more than 1.5 mm.
Bilateral condyle fractures were treated with arch bars and guiding elastics except when no occlusal disturbances were present. Rigid intermaxillary fixation was not used. If occlusal disturbances occurred over time, additional guiding elastics were added. The arch bars were removed after 6 weeks.
During the first 3 weeks of recovery the patients were advised to follow a soft food diet. A gradual increase in food consistency was allowed depending on complaints.
Standard follow-up appointments were made at 1 week, 3 weeks, 6 weeks, and 12 weeks after trauma.
During the first visit to the department (T0), for diagnosing the fracture, the patients were asked whether they had experienced any pain, restricted mouth opening, joint sounds or occlusal problems before the accident, and if so whether these problems had caused mandibular function impairment.
Patients were invited to visit the department for follow-up at 6 months and 12 months after fracturing the mandibular condyle. If the patient failed to meet the appointment, a new invitation was sent. If the patient did not respond after 2 weeks, a reminder was sent. If the patient failed to respond to that no further action was undertaken. At follow-up (6 months and 12 months) a physical examination was performed by one examiner (PD). The presence of joint sounds and pain during mandibular movements was assessed. Pain was assessed on palpation of the temporomandibular joints and the muscles of mastication. Maximal mouth opening, left and right lateral mandibular movement, and protrusion were measured as described previously . Dentition and occlusion were assessed by an oral and maxillofacial surgeon (RB). Patients were requested to fill out the mandibular function impairment questionnaire (MFIQ). The MFIQ was designed to assess the patient’s perception of mandibular function impairment. It consists of 17 items, each item is presented with a 5 point Lickert scale on which the patient can indicate how much difficulty was experienced while performing a particular mandibular movement or task (e.g. eating food, speaking, drinking, laughing, yawning). The scores of the 5 point Lickert scale are: 0 = no difficulty, 1 = a little difficulty, 2 = quite a bit of difficulty, 3 = much difficulty, 4 = very difficult or impossible without help. The MFIQ has a scoring range from 0 to 68, where 0 indicates no mandibular function impairment .
The average pain intensity experienced during the week prior to follow-up was assessed using a visual analog scale (VAS) of 100 mm. Patients were asked how they rated their occlusion (good, moderate, poor).
For this study the results of the assessments at 12 months after trauma were used, if these data were missing the data from the 6 months follow-up were used (last observation carried forward).
This study was approved by the medical review board of the University Medical Center Groningen.
Statistical analyses were performed in SPSS (Version 16.0) for Windows. In this study the factors possibly associated with mandibular function impairment were: presence of pain (either perceived during physical examination or assessed on the VAS), joint sounds, maximal mouth opening, occlusion disturbances, horizontal movement of the mandible (left and right, and protrusion), perceived occlusion good (yes, no), complete dentition, sex, and age.
A multivariate linear regression analysis was performed with the MFIQ scores as dependent variable and the factors of possible influence on mandibular function impairment as possible predictors. The residuals of the linear regression analysis were not normally distributed. Logarithmic transformation of the data did not result in a normal distribution of the residuals. The MFIQ scores were dichotomized as no function impairment (0) and function impairment (≥1) and entered in a multivariate logistic regression analysis (stepwise backward) as dependent variable. For all statistical tests, a significance level of 0.05 was used.
Initially, 144 patients with fractures of the mandibular condyle were included in this study. Follow-up data were present for 119 patients (83%). Two patients were excluded because MFIQ data were not available. Another two patients were excluded because they received open reduction for comminuted multiple mandibular fractures. An additional patient was excluded because of function impairment prior to trauma. The data from 114 patients (79%), 36% woman ( n = 41) and 64% men ( n = 73), were available for analysis. Of the 114 patients, 88 had a follow-up of 12 months and 26 had a follow-up of 6 months. The mean age of the patients was 28.1 years (SD 13.3). Patient, accident and fracture characteristics are summarized in Table 1 .
|Variables ( n )||Mean (SD)||Frequency (%)|
|Age (113)||28.1 (13.3)|
|Partial dentate||16 (14%)|
|Accident characteristics (114)|
|Traffic accidents||66 (58%)|
|Other (sports injury, occupational injury)||7 (6%)|
|Intra articular fracture (113)|
|Right side||12 (11%)|
|Left side||17 (15%)|
|Condylar neck fractures (113)|
|Right side||56 (50%)|
|Left side||60 (53%)|
|Bilateral fractures (113)||31 (27%)|
|Displacement of fracture (113)|
|Dislocation of fracture (112)||22 (20%)|
|Additional mandibular fractures (113)|
The most common cause of the fractures was a traffic accident (in 66 patients). Condylar neck fractures were the most common fractures and were present in 50% of the patients. Additional mandibular fractures were found in 52% of all patients.
The results of the follow-up assessments are summarized in Table 2 . VAS pain data had a highly skewed distribution so it was dichotomized into ‘pain reported’ present or absent. Of 114 patients, 10 (9%) experienced pain and 45 (39%) had a MFIQ ≥ 1. The mean MFIQ scores were low, 3.4 (SD 7.3). The mean mouth opening was 51.9 (SD 8.4). Occlusion was perceived as ‘good’ by 76% of patients.
|Variables ( n )||Mean (SD)||Frequency (%)|
|VAS pain (114)||2.3 (9.4)|
|Pain reported (114)||10 (9%)|
|Perceived occlusion (112)|
|MFIQ (114)||3.4 (7.3)|
|MFIQ score ≥ 1 (114)||45 (39%)|
|Physical examination *|
|Range of motion of the mandible|
|Maximal mouth opening (112)||51.9 (8.4)|
|Left lateral movement (110)||9.2 (2.8)|
|Right lateral movement (109)||8.9 (2.8)|
|Protrusion (110)||8.8 (2.9)|
|Abs (left–right lateral movements) (109)||2.2 (1.9)|
|Symmetric left, right movements) (109)||24 (22%)|
|Maximal occlusion (110)||102 (93%)|
|Joint sounds (114)||36 (32%)|
The results of the regression analysis are summarized in Table 3 . The beta values (regression coefficients) of mouth opening and absolute difference between left and right mandibular movements were not significant ( p = 0.059 and p = 0.072, respectively). Removing the latter two predictors from the regression equation resulted in a significant decrease in model fit, therefore they remained as predictors in the regression equation.
|Predictors||B||Se β||P of β||e β = OR||95% C.I. e β|
|Pain (yes = 1: no = 0)||2.057||0.955||0.031||7.825||1.204–50.842|
|Perceived occlusion (good = 0: moderate/poor = 1)||1.278||0.527||0.015||3.589||1.278–10.081|
|Mouth opening (per mm)||−0.054||0.029||0.059||0.947||0.895–1.002|
|Absolute difference between left and right movements (per mm)||0.215||0.120||0.072||1.240||0.981–1.567|
|Age (per year)||0.047||0.019||0.016||1.048||1.009–1.088|
The odds ratio of having mandibular function impairment was larger when pain was present (7.8), occlusion was perceived as moderate or poor (3.6), the absolute difference between left and right lateral movement was larger (1.2) and if patients were older (1.05). The odds ratio of having mandibular function impairment was less when mouth opening (0.95) was larger. Thus larger mouth opening was a protective factor.
Clinically, the results of the logistic regression analysis enabled the calculation of the risk of having mandibular function impairment in an individual by using the formula:
p ( mandibular function impairment ) = e s 1 + e s
In this formula, p (mandibular function impairment) is the risk of having mandibular function impairment, s is the regression score of that individual, and e = 2.72.
For example, the risk of having mandibular function impairment in subject A, a male of 50 years, who experiences no pain, has moderate occlusion, a mouth opening of 30 mm and who has no absolute difference between left and right movements, can be calculated as follows:
s ( regression score subject A ) = 0 × 2.057 + 1 × 1.278 + 30 × − 0.054 + 0 × 0.215 + 50 × 0.047 − 0.031 = 1.977 .
e 1.977 = 7.22
p ( mandibular function impairment ) = 7.22 1 + 7.22 = 0.878 .
By contrast, the risk of having mandibular function impairment in subject B, a female of 20 years, who experiences no pain, who has good occlusion, a mouth opening of 55 mm and who had no absolute difference between left and right movements, can be calculated as follows:
s ( regression score subject B ) = 0 × 2.057 + 0 × 1.278 + 55 × − 0.054 + 0 × 0.215 + 20 × 0.047 − 0.031 = − 2.061