ORIGINAL RESEARCH

https://doi.org/10.5005/jp-journals-10015-2254
World Journal of Dentistry
Volume 14 | Issue 6 | Year 2023

Assessment of Condylar Position in Treated Unilateral Unfavorable Mandibular Angle Fracture After 1-year Follow-up: A Prospective Study

Kathirvel Gopalakrishnan1, Reena R John2, Balamanikandasrinivasan Chandrasekaran3

1-3Department of Oral and Maxillofacial Surgery, Vinayaka Mission’s Sankarachariyar Dental College, Vinayaka Mission’s Research Foundation (Deemed to be university), Salem, Tamil Nadu, India

Corresponding Author: Balamanikandasrinivasan Chandrasekaran, Department of Oral and Maxillofacial Surgery, Vinayaka Mission’s Sankarachariyar Dental College, Vinayaka Mission’s Research Foundation (Deemed to be university), Salem, Tamil Nadu, India, Phone: +91 86681 97369, e-mail: drbalamanikandasrinivasan@vmsdc.edu.in

Received on: 07 May 2023; Accepted on: 09 June 2023; Published on: 22 August 2023

ABSTRACT

Aim: To assess the function and three-dimensional position of the condyle in unilateral horizontally unfavorable mandibular angle fracture preoperatively and 1-year postoperatively using the Helkimo clinical dysfunction index and computed tomography (CT), respectively.

Materials and methods: A total of 10 patients with unilateral horizontal unfavorable angle fractures were subjected to clinical and radiographic assessment before and 1-year after surgical management. The position of the condyle was evaluated through CT and compared between the following groups—group I, preoperative fractured vs nonfractured side; group II, postoperative fractured vs nonfractured side; group III, preoperative vs postoperative fractured side. Statistical analysis was done with the Chi-square and paired student t-test.

Results: Clinical evaluation showed severe dysfunction in 80% of patients preoperatively and showed no dysfunction in 80% of patients postoperatively (p = 0.001). CT evaluation in groups I and III showed changes in superior joint space (S1) and condylar angulation (CA) which was statistically significant (p < 0.05).

Conclusion: This study has given insight into the potential long-term changes in the position and function of the condyle in unilateral unfavorable angle fractures. Though CT evaluation showed changes, its implications in terms of clinical symptoms were minimal.

Clinical significance: From this study, it is understood that angle fracture influences condylar position in the sagittal and axial plane. Operating surgeons should remember that in a continuous bone-like mandible, a fracture of one part can impact the other. Therefore, appropriate fixation of angle fracture following protocols is paramount to avoid long-term Tempero Mandibular Joint (TMJ) dysfunction.

How to cite this article: Gopalakrishnan K, John RR, Chandrasekaran B. Assessment of Condylar Position in Treated Unilateral Unfavorable Mandibular Angle Fracture After 1-year Follow-up: A Prospective Study. World J Dent 2023;14(6):503-509.

Source of support: Nil

Conflict of interest: None

Keywords: Computed tomography analysis, Condyle position, Helkimo dysfunction index, Mandibular angle fracture, Unfavorable fracture.

INTRODUCTION

The mandible is a unique bone in the humans because of its form and function. The parabola shape of the mandible and the location of attachments of the muscles that elevate and depress the mandible make the pattern of fracture in this bone very predictable based on the direction, and energy imparted by the impact on the bone. The shape of the mandible is such that it resembles a Hunting bow in the manner in which the different forces of compression, tension, and torsion affect it when it is impacted by an external force. This bone is also affected by the manner of deposition and resorption of bone as explained by the Enlow V principle which again affects the pattern of fracture in different age-groups.

Articulation of the mandible with maxilla through dentition and with the skull base by the condyle helps in its synchronized movements.1 Mandibular angle is formed by the junction of the body and ramus where the bone is thinner in cross-section and the presence of a third molar further weakens the region.2,3 The angle of the mandible can get disrupted due to various etiologies—the most common being the fracture of the mandible.4,5 Among them, the incidence of angle fracture ranges from 27 to 30%.6 Fracture of mandibular angle occurs due to both direct and indirect injuries.7 The bone trajectories of the mandible run longitudinally in the horizontal corpus of the mandible which influences the propagation of the fracture line which forms the basis of Champy’s lines of osteosynthesis.7

Horizontal unfavorable angle fractures result in displacement of the proximal segment of the angle along with the condyle due to the influence of pterygo-masseter and temporalis muscle action.6,7 As the displaced segment of the angle is continuous with the mandibular condyle, it can be assumed that the condylar position may be influenced by the displaced fractures of the mandibular angle which in turn can affect condylar function. Assessment of condylar position after its fixation has been reviewed in the literature but the influence of mandibular angle fracture on condylar position has not been reported.

Therefore, this study intends to investigate the relationship between unilateral horizontally unfavorable mandibular angle fracture and position of condyle. The null hypothesis of this study will be that there is no relationship between unilateral horizontally unfavorable mandibular angle fracture and condyle position. The aim of this study is to assess the three-dimensional position of the condyle in unilateral horizontally unfavorable mandibular angle fracture preoperatively and 1-year postoperatively using computed tomography (CT). The objectives are to assess the condyle position of the fractured angle side with the contralateral normal side preoperatively and postoperatively after 1-year to compare the preoperative and 1-year postoperative position of the condyle in the fractured side and to assess the impact of angle fracture on the condyle in terms of position and function at 1-year postoperative period.

MATERIALS AND METHODS

This prospective study was carried out from December to August 2020 in the Department of Oral and Maxillofacial Surgery, Vinayaka Mission’s Sankarachariyar Dental College, Vinayaka Mission’s Research Foundation (Deemed to be University), Salem, Tamil Nadu, India, Salem which included surgery and 1-year follow-up also. Around 10 patients with unilateral unfavorable angle fractures who were willing for treatment and to be part of this study were included in this study. The study was approved by the Institutional Ethical Committee (IEC no: VMSDC/IEC/Approval no. 264). Around 10 male patients with ages ranging from 19 to 47 years (mean age of 30.7 years) participated in the study (Table 1). Surgery was performed in all patients by a single operator to reduce the bias. Two investigators who are Professors in the specialty of oral and maxillofacial surgery with >5 years of experience assessed the patients clinically and radiographically in the study. Patients with unilateral horizontally unfavorable mandibular angle fractures who gave consent to participate in the study were included and patients with comminuted angle fractures, associated multiple mandibular fractures, and neuromuscular disorders were excluded.

Table 1: Demographic details of patients with unfavorable angle fracture of the mandible
Patient Age/sex Side of fracture Follow-up
Right/left
1 30/M Right 1 year
2 25/M Left 1 year
3 33/M Left 1 year
4 41/M Right 1 year
5 42/M Right 1 year
6 20/M Left 1 year
7 19/M Left 1 year
8 25/M Left 1 year
9 47/M Left 1 year
10 25/M Left 1 year

Open reduction and internal fixation (ORIF) were done as per the protocol suggested by Moraissi and Ellis et al. in all patients.8 The fractures were approached intraorally with a vestibular incision extending to the ascending ramus. The periosteum was stripped from the bone to expose the fracture and a miniplate of 2.0 mm with bicortical screws of 8 mm was used for fixation (Figs 1 to 3—depict the preop, intraoperative, and 1-year postoperative clinical and radiographic follow-up of the case with operated left angle fracture).

Figs 1A and B: (A) Preoperative clinical picture; (B) Preoperative CT showing horizontally unfavorable angle fracture in the left side

Fig. 2: Intraoperative: ORIF under general anesthesia

Figs 3A and B: (A) Postoperative clinical picture after 1-year follow-up; (B) Postoperative CT after 1-year follow-up showing fixation of miniplate in left angle of mandible

Helkimo clinical dysfunction index was recorded for all patients pre and postoperatively to ensure consistency.9 Sum of the scores were calculated before and after 1-year of surgical management and compared. A score “0” is given where no clinical symptoms were present and 1–4 for mild, 5–9 for moderate, and 10–25 for severe dysfunction.9 Position of the condyle was assessed through a Revolution Aspire Computed Tomography 16 slice CT scan. (GE Medical Systems) of 0.6 mm thickness using radiographic landmarks in coronal, sagittal, and axial planes given by Choi et al.10

All patients had periodical follow and function and the position of the condyle was assessed postoperatively after 1-year through the Helkimo clinical dysfunction index and CT scan.

The following parameters were measured in CT:

Figs 4A and B: Assessment of condyle position in CT scan—axial section. (A) Preoperative measurement of CD and angulation; (B) Postoperative measurement of CD and angulation

Figs 5A and B: Assessment of condyle position in CT scan—coronal plane. (A) Preoperative measurement of CS; (B) Postoperative measurement of CS

Figs 6A to D: Assessment of condyle position on CT scan in the sagittal plane. Preoperative measurements of S1, closest anterior and posterior joint space. (A) On the fractured side; (B) On the normal side postoperative measurements of S1, closest anterior, and posterior joint space; (C) On the fractured side; (D) On the normal side

The data was tabulated and a comparison was made between the following groups:

Data were subjected to statistical analysis in Statistical Package for the Social Sciences version 21.0 software. Chi-square test and paired student t-test were done. The association between the condyle’s function preoperatively and 1-year postoperatively has been evaluated through the Chi-square test. Positional changes between preoperatively and 1-year postoperatively fixation of angle fractures were evaluated through paired t-tests.

RESULTS

Five patients (50%) were in the 18–30 years and five (50%) were between 31 and 50 years age-group. The mean age of the patients was 30.7 years. The most common site of fracture in the present study was left side—70% (n = 7). At the time of injury, all patients had deranged occlusion and had symptoms such as restriction in mouth opening and deviation of the mandible during opening or closing.

Preoperative evaluation by the Helkimo clinical dysfunction index revealed the presence of severe and moderate dysfunction in 80% (n = 8) and 20% (n = 2) patients, respectively. At the end of 1-year follow up 80% (n = 8) showed no dysfunction and 20% (n = 2) showed mild dysfunction (p = 0.001) (Fig. 7).

Fig. 7: Clinical evaluation through Helkimo clinical dysfunction index

On comparison between the preoperatively fractured vs nonfractured side through CT, changes were revealed in CA (affected side—22.950 ± 1.522°, unaffected side—19.960 ± 2.622°) (p = 0.015) and S1 (affected side—2.439 ± 1.027 mm, unaffected side—2.940 ± 1.125 mm) (p = 0.022) in group I which was statistically significant (Table 2).

Table 2: Comparison between preoperative fractured vs nonfractured side
Preoperative N Mean Standard deviation Standard error t p
CD Fractured 10 4.072 0.255 0.081 1.636 0.136
Normal 10 3.979 0.261 0.083
CA Fractured 10 22.950 1.522 0.481 3.002 0.015*
Normal 10 19.960 2.622 0.829
CS Fractured 10 3.066 1.269 0.401 2.149 0.060
Normal 10 3.822 2.171 0.687
S1 Fractured 10 2.439 1.027 0.325 2.424 0.022*
Normal 10 2.940 1.125 0.356
S2 Fractured 10 1.496 0.800 0.253 0.481 0.642
Normal 10 2.940 1.125 0.356
S3 Fractured 10 1.496 0.800 0.253 0.560 0.589
Normal 10 1.374 0.368 0.116

*Significant at 5%. CA, condylar angulation; CD, condylar distance; CS, condylar space; S1, the superior joint space; S2, the closest anterior joint space; S3, the closest posterior joint space

On comparison between preoperatively and 1-year postoperatively CT, changes were noted in CA (preoperatively—22.95 ± 1.522°, postoperatively—19.72 ± 3.590°) (p = 0.046) and S1 (preoperatively—2.44 ± 1.027 mm, postoperatively—3.31 ± 0.604 mm) (p = 0.024) in group III, which was statistically significant (Table 3). The results of this study infer that horizontally unfavorable angle fractures can influence the condylar position in both the sagittal and axial plane. However, when the measurements were compared between the postoperatively fractured and nonfractured side (group II), the values were not statistically significant (Table 4).

Table 3: Comparison between fractured side: preoperative vs postoperative
Affected N Mean Standard deviation Standard error t p
CD Pre 10 4.07 0.26 0.08 0.767 0.463
Post 10 4.05 0.23 0.07
CA Pre 10 22.95 1.522 0.481 2.319 0.046*
Post 10 19.72 3.590 1.135
CS Pre 10 3.07 1.27 0.40 0.449 0.664
Post 10 2.88 0.90 0.28
S1 Pre 10 2.44 1.027 0.325 2.704 0.024*
Post 10 3.31 0.604 0.191
S2 Pre 10 1.50 0.80 0.25 1.516 0.164
Post 10 1.23 0.33 0.11
S3 Pre 10 2.26 0.97 0.31 0.300 0.771
Post 10 2.17 0.79 0.25

*Significant at 5%. CA, condylar angulation; CD, condylar distance; CS, condylar space; S1, the superior joint space; S2, the closest anterior joint space; S3, the closest posterior joint space

Table 4: Comparison between postoperative fractured vs nonfractured side
Postoperative N Mean Standard deviation Standard error t p
CD Fractured 10 4.047 0.234 0.074 0.770 0.461
Normal 10 4.005 0.221 0.070
CA Fractured 10 19.720 3.590 1.135 0.422 0.683
Normal 10 20.220 2.801 0.886
CS Fractured 10 2.875 0.901 0.285 1.868 0.095
Normal 10 2.605 0.582 0.184
S1 Fractured 10 3.314 0.604 0.191 0.628 0.546
Normal 10 3.207 1.000 0.316
S2 Fractured 10 1.229 0.334 0.106 1.959 0.082
Normal 10 1.421 0.320 0.101
S3 Fractured 10 2.169 0.793 0.251 1.622 0.139
Normal 10 1.758 0.573 0.181

*Significant at 5%. CA, condylar angulation; CD, condylar distance; CS, condylar space; S1, the superior joint space; S2, the closest anterior joint space; S3, the closest posterior joint space

On comparison between the preoperatively fractured vs nonfractured side through CT, changes were revealed in CA (p = 0.015) and S1 (p = 0.022) in group I which was statistically significant (Table 2). On comparison between preoperatively and 1-year postoperatively CT, changes were noted in CA (p = 0.046) and S1 (p = 0.024) in group III which was statistically significant (Table 3). The results of this study infer that horizontally unfavorable angle fractures can influence the condylar position in both the sagittal and axial plane. However, when the measurements were compared between postoperatively fractured and nonfractured sides (group II), the values were not statistically significant (Table 4).

DISCUSSION

The mandibular angle has a distinctive curved morphology which is influenced by the strong masticator muscles. These muscles determine the direction of displacement during the fracture by creating tensile forces in the superior border and compressive forces in the inferior border.1,3 The most important goal in the management of mandibular angle fracture as with any other facial bone fracture is to restore form and function to pretrauma state.

In horizontally unfavorable angle fractures, such displacement can cause overriding between proximal and distal segments of the mandible. Since the condyle is a part of the proximal segment, the displacement that happens due to angle fracture can affect temporomandibular joint (TMJ) function and its dysfunction. The harmony between the condyle and articular fossa should be maintained in its normal anatomical position to prevent stretching of the articular ligaments and muscles which may lead to long-term complications such as pain, occlusal instability, and degenerative joint changes.11 Therefore, the need to assess TMJ function arises in terms of the range of movements, function, and pain during motion which was assessed using the Helkimo dysfunction index in this study. This index is helpful for grading various symptoms of TMJ using a specific set of variables and scores.

Several studies are prevalent in the literature on the fixation of angle fractures and about changes in condyle position in condyle fracture.3,8,12,13 But, the influence of angle fracture on condyle’s function and position with 1-year postoperative follow-up has not been discussed in the earlier literature. The operating surgeon should remember that the effect of a fractured part need not be confined only to that affected area but can influence adjacent areas as is the case with the mandibular angle fracture.

The changes that happen in a condylar position due to angle fracture need not be the same as the condylar position in a condylar fracture as the influence of muscle pull and biomechanics differ in both conditions despite their proximity. Clinical evaluation of this study showed no dysfunction in eight out of the 10 patients and mild dysfunction in two patients after 1-year follow-up.

Literature evidence with regards to the influence of condylar fracture on temporomandibular joint function and its position showed the following results. Suhas and Ramdas assessed temporomandibular joint dysfunction in condylar fracture patients using the Helkimo index. Around 33 cases that were reviewed at the 8th week postoperatively showed no dysfunction in 9%, mild dysfunction in 60%, and moderate dysfunction in 30% of cases. None had severe dysfunction. Their study showed higher dysfunction when compared with the current study.9

The 6-month follow-up of 31 patients by Rajantie et al. on assessment of temporomandibular dysfunction in mandibular fractures not involving condyle revealed mild dysfunction in 19 patients (61.3%) and moderate dysfunction in six patients (19.4%), and none had severe dysfunction.14

Kumar assessed temporomandibular dysfunction using the Helkimo index in condylar fractures at the 10th postoperative week and found that 64% had mild dysfunction, 24% had moderate dysfunction only 12% had no dysfunction. When comparing their results with the current study, the results were similar inferring that mandibular angle fracture can also have an influence on the TMJ function and position.15

Computed tomography (CT) images help to evaluate the spatial localization of condyle position. The condylar position on CT was assessed based on the landmarks described by Choi et al.10 The position of the condyle in horizontally unfavorable angle fracture is displaced superiorly causing a reduction in S1 and medially rotated along the horizontal axis in groups I and III. When compared between postoperative fracture and nonfractured side (group II) statistical analysis revealed no significant changes between them which implies that after correct fixation of angle fracture, condyle position in glenoid fossa and angulation of condylar head replicated the nonfractured side.

Two out of 10 treated patients had mild dysfunction on clinical evaluation through the Helkimo clinical dysfunction index. This implies that, although positional changes of condyle were noted with respect to CA and S1, those changes had only minimal clinical effects in terms of function. This could be due to adaptive mechanisms of surrounding masticatory muscles during postoperative healing as stated by Choi.13 Smaller sample size and study results based on a single institution are the limitations of this study.

CONCLUSION

The influence of the angle fractures on condylar position has not been studied elsewhere and has scope for research. With the present sample size, this paper concludes that horizontally unfavorable angle fractures influence condylar position in the sagittal and axial plane. The condylar malposition gets corrected by following proper fixation protocols of the mandibular angle fracture. Therefore, it is paramount to fix angle fractures following proper protocols to avoid long-term TMJ dysfunction.

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