Displaced mandibular angle fracture with a tooth in the fracture line
A 26-year-old man is brought to the emergency department after a road traffic accident. He has a 2 cm laceration of the chin, an anterior open bite and a step deformity in the right angle region. CT shows a displaced unfavourable right mandibular angle fracture, a minimally displaced left parasymphysis fracture, and a non-displaced right condylar head fracture. Tooth 38 is partially erupted in the angle fracture line; it is not mobile, not tender to percussion and there is no pericoronitis. Mouth opening is 18 mm; there is no airway compromise, no cervical spine injury and GCS is 15. He is fit and well, takes no medication and has no allergies.
1. Would you treat this with closed reduction and maxillomandibular fixation or open reduction and internal fixation? Justify the choice for each fracture.
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Right angle: an unfavourable, displaced angle fracture with a step deformity and malocclusion is the classic indication for open reduction and internal fixation. The masseter and medial pterygoid elevate the proximal segment, so closed treatment is mechanically less stable, and ORIF allows anatomical reduction, earlier function and faster return to work and diet. A single miniplate along Champy's ideal line, or two plates for a comminuted or severely displaced fracture, via an intraoral approach, would be my plan.
Left parasymphysis: even though minimally displaced, this is functionally a bilateral fracture when combined with the angle. The geniohyoid and digastric pull the symphysis down and back, and fixation of one side without the other leaves the mandible unstable. Both should be fixed, restoring occlusion first.
Right condyle: non-displaced, so no fixation. Condylar fractures are managed closed with early mobilisation and physiotherapy, since prolonged immobilisation risks ankylosis and reduced opening. The condyle serves as the posterior vertical stop once the other fractures are reduced.
Practical point: reduction is judged by occlusion, not by the radiograph, so establish the pre-injury occlusion with temporary maxillomandibular fixation before plating.
2. What would you do with tooth 38, and on what criteria?
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The default is to retain it, and this tooth meets the retention criteria: it is not mobile, not tender, not fractured, has no pericoronitis, no caries or periapical pathology, and it does not prevent reduction.
Reasons to retain: the tooth preserves alveolar bone and a possible future abutment, and removing it can convert a favourable fracture into a defect and destabilise reduction.
Criteria for extraction in the fracture line: mobility of the tooth or of a fragment, a fractured or exposed root, established infection or pericoronitis, unrestorable caries or periapical pathology, a tooth that physically prevents anatomical reduction, or a badly comminuted fracture segment. Extraction must then be done carefully to avoid displacing a fragment or the tooth into the submandibular space.
If retained: record it explicitly in the plan, give prophylactic antibiotics covering oral flora, review clinically and radiographically at 1-2 weeks and 6 weeks, and warn the patient that a partially erupted third molar in a fracture line carries a higher infection risk and may need later removal. If infection develops or the fracture fails to heal, remove it then. Do not leave the decision implicit - an unrecorded 'tooth in the line' is a common source of avoidable morbidity.
3. Outline the sequence of management, including antibiotics, fixation duration and follow-up.
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Emergency phase: ATLS priorities first - airway, breathing, circulation, cervical spine clearance and haemorrhage control. The chin laceration is cleaned, explored for a through-and-through component and repaired; tetanus status is checked; baseline photographs and occlusion are recorded. Analgesia and a single preoperative intravenous antibiotic dose (for example co-amoxiclav, or clindamycin if penicillin-allergic) are given, with the drug continued for no more than 24 hours postoperatively - prolonged courses have not been shown to reduce infection and select resistant flora.
Surgical phase: theatre within 24-72 hours once medically fit. Establish the pre-injury occlusion with temporary maxillomandibular fixation, reduce and plate the angle and parasymphysis via intraoral approaches, and release fixation at the end of surgery to check the occlusion.
Postoperative phase: soft diet, chlorhexidine mouthwash, analgesia, and early mobilisation of the condyle with jaw exercises and physiotherapy. If stable fixation is achieved, rigid maxillomandibular fixation is unnecessary; if fixation is judged less stable, guided elastic traction for 2-3 weeks rather than 6 weeks of rigid fixation.
Follow-up: at 1 week (wound, occlusion, infection), 6 weeks (occlusion, union, remove any arch bars), and 3 months (mouth opening, nerve function, radiograph if indicated). Warn about altered sensation in the lower lip and about plate removal only if it becomes symptomatic.