Abstract
The aim of this retrospective study was to investigate the clinical characteristics of superolateral dislocation of the mandibular condyle, and to review our experience of its treatment. Thirteen patients were included in this study. Demographic information and details of their original injury were analyzed by descriptive statistics and the treatment methods were summarized. These patients could be classified into three types: (1) unilateral dislocation with isolated condylar fracture ( n = 3); (2) unilateral dislocation with associated condylar fracture and other mandibular fracture ( n = 7); (3) bilateral dislocation with associated condylar fracture and other mandibular fracture ( n = 3). Treatment involved three main aspects: (1) relief of the condylar dislocation by manual manipulation or open reduction; (2) reduction of the medial condylar fragment and fixation with screws, or removal of the fragment if less than 50% of the condylar width; however, in one case with a tiny condylar fragment, this was left in situ ; (3) management of the other associated mandibular fractures by open reduction and internal fixation (ORIF). Follow-up ranged from 6 to 20 months (average 13.69 months). Satisfactory functional outcomes were achieved in these cases. The results of this study indicate that superolateral dislocation of the condyle assumes many forms, and the treatment depends on the presence of fractures.
According to the direction of displacement, complete dislocation of the mandibular condyle from the mandibular fossa can be classified as anterior, posterior, lateral, or superior. Allen and Young classified lateral dislocations into type I (lateral subluxation) and type II (complete dislocation), in which the condyle is forced laterally and then superiorly. However, superolateral dislocation of the condyle occurs very infrequently. Superolateral dislocation of the condyle is frequently associated with fractures of the mandible. The previous literature on patients with superolateral dislocation of the mandibular condyle consists mostly of case reports, with no systematic research.
The purpose of this retrospective study was to investigate the clinical characteristics of superolateral dislocation of the mandibular condyle, and to review our experience of the treatment of these cases.
Patients and methods
All patients identified as suffering superolateral dislocation of the mandibular condyle presenting to the Department of Oral and Maxillofacial Surgery between January 2007 and January 2012, were included in this retrospective study. This research was approved by the local institutional review board and was conducted in accordance with the local institutional review board standards and the guidelines of the Declaration of Helsinki.
The following information was collected from the medical records: patient gender, age, aetiology of injury, site of injury, and form of injury. Demographic information and details of the original injury were tabulated and analyzed by descriptive statistics. At the same time, the methods of treatment were analyzed and summarized, including how the condylar dislocation was relieved, how the associated fractures were managed, and whether there was any associated management (i.e. to the articular soft tissues).
The follow-up period ranged from 6 to 20 months (average 13.69 months). Postoperative assessment of the 13 patients was conducted. A radiologic assessment (panoramic radiograph or computed tomography (CT)) was performed during the follow-up. The follow-up consisted of regular clinical assessment of maximum mouth opening, deviation on opening, nerve injury, and pain. The follow-up results determined the need for supplemental management such as mobilization or physiotherapy.
Results
Thirteen patients suffering superolateral dislocation of the mandibular condyle were included in the study ( Table 1 ); 11 were males and two were females. Their ages ranged from 18 to 45 years, with a mean of 29.38 years. The aetiology of the injury included traffic accidents ( n = 11) and falls ( n = 2). All patients were injured by direct force on the mandibular symphysis or body.
| Case No. | Gender | Age (years) | Aetiology | Dislocation condition | Sagittal split of condyle (size) | Treatment of condyle fracture | Associated mandibular fracture | Treatment of mandibular fracture | Time of follow-up (months) | Maximum opening (mm), Pre/Post | Deviation on opening Post (mm) | Nerve injury |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | M | 28 | TA | Uni | Tiny | No treatment | No fracture | – | 12 | 0/39 | 0 | No |
| 2 | M | 31 | TA | Uni | 1/3–1/2 | Remove | Symph | ORIF | 12 | 10/38 | 1 | No |
| 3 | M | 19 | TA | Uni | >1/2 | Screw fixation | Symph | ORIF | 12 | 8/36 | 1 | No |
| 4 | M | 42 | TA | Uni | 1/3–1/2 | Remove | Symph | ORIF | 18 | 12/34 | 0 | No |
| 5 | M | 36 | TA | Uni | >1/2 | Screw fixation | No fracture | – | 20 | 2/39 | 0 | No |
| 6 | F | 19 | TA | Uni | 1/3–1/2 | Remove | Symph | ORIF | 13 | 13/36 | 1 | No |
| 7 | M | 25 | TA | Uni | <1/3 | Remove | Body | ORIF | 6 | 15/34 | 2 | No |
| 8 | M | 22 | TA | Uni | >1/2 | Screw fixation | Symph | ORIF | 10 | 12/35 | 0 | a |
| 9 | M | 18 | TA | Uni | 1/3–1/2 | Remove | No fracture | – | 19 | 10/40 | 2 | No |
| 10 | F | 36 | Fall | Uni | 1/3–1/2 | Remove | Body | ORIF | 12 | 7/36 | 0 | No |
| 11 | M | 43 | Fall | Bi | Lt < 1/3; Rt > 1/2 | Remove (Lt); screw fixation (Rt) | Symph and body | ORIF | 16 | 6/33 | 1 | No |
| 12 | M | 18 | TA | Bi | Both 1/3–1/2 | Remove | Symph | ORIF | 15 | 5/28 | 2 | No |
| 13 | M | 45 | TA | Bi | Both <1/3 | Remove | Symph | ORIF | 13 | 8/35 | 0 | No |
| N = 13 | M = 11; F = 2 |
18–45; Avg = 29.38 |
TA = 11; Fall = 2 | Uni = 10; Bi = 3 | Tiny = 1; <1/3 = 4; 1/3–1/2 = 7; >1/2 = 4 |
No treatment = 1; Remove = 11; Screw fixation = 4 | No fracture = 3; Symph = 7; Body = 2; Symph and body = 1 |
No fracture = 3; ORIF = 10 | 6–20; Avg = 13.69 |
Pre Avg = 8.31; Post Avg = 35.62 |
Avg = 0.77 | No |
Among the 13 patients, three cases suffered bilateral condyle dislocation and 10 cases suffered unilateral dislocation. Sagittal split of the medial condyle, varying in size ( Fig. 1 ), occurred simultaneously in all the 16 dislocated condyles. One of these cases was accompanied by a zygomatic arch fracture ( Fig. 2 A and B). Of the 13 patients, three had no other associated mandibular fracture except for the condylar fracture ( Fig. 3 ); the other 10 cases had other associated fractures in the symphyseal or body region of the mandible ( Fig. 4 ). Based on the clinical manifestations, the 13 patients in this study could be classified into three types: (1) unilateral dislocation with isolated condylar fracture ( n = 3); (2) unilateral dislocation with associated condylar fracture and other mandibular fracture ( n = 7); (3) bilateral dislocation with associated condylar fracture and other mandibular fracture ( n = 3).
