CASE 53 SUBTALAR DISLOCATION
|
KS |
A 28-year-old man is brought to the emergency department after falling from a high wall late in the evening at around 10 p.m. He has a clinically swollen and deformed foot and ankle, and a single radiograph is shown here.
- Describe this x-ray.
This is an AP radiograph of the tibia, ankle and hindfoot. The view is partially obscured by a plaster or splint. The radiograph shows a medial subtalar dislocation with the calcaneus and the rest of the foot displaced medial to the talus.
- This is an isolated injury. Describe your initial management of the patient and this injury.
Having treated this patient along ATLS guidelines and established that this is an isolated injury, I would examine the limb carefully, looking to identify any open wounds or threatened skin as a result of the dislocation. I would ensure that the patient had adequate analgesia and make a careful assessment of the neurovascular status. The radiograph does not show any obvious associated fractures, but I would scrutinise it carefully. I would arrange to perform a closed reduction of the disloca- tion in the emergency department under sedation. I would assess the stability of the reduction, repeat the neurovascular assessment, place the patient in a below knee backslab and confirm the reduction with further radiographs.
- If it is not possible to achieve a closed reduction, how would you proceed?
In this situation I would make arrangements to take the patient to the operating theatre. I would attempt a closed reduction under formal general anaesthesia, and should this fail, I would undertake this as an open procedure in the operating the- atre. If a CT could be arranged urgently then I would arrange it, but I would not allow this to cause delay, especially where there is evidence of vascular injury, threatened skin or soft tissue compromise. In the operating theatre, once consented, positioned and anaesthetised, I would use an anteromedial incision. A closed reduction may be prevented by the talar head becoming buttonholed through the capsule, caught in the extensor retinaculum or impacted into the navicular, causing a mechanical obstruction to reduction. An open approach would allow me to identify and address any of these. I would debride and wash out any wounds and confirm the reduction using image intensification. I would also scrutinise the images for evidence of any associated fractures. I would arrange further imaging with CT after reduction if not already obtained.
- Describe your plan for definitive management.
Most subtalar dislocations without significant associated fractures are stable after reduction. Treatment in a non-weight bearing below knee cast for 6 weeks is usu- ally sufficient. Where the reduction is unstable as a result of the injury or following debridement, CT may identify additional fractures that should be treated. Where the reduction is unstable as a result of soft tissue injury, I would stabilise the subtalar and talonavicular joints with smooth Steinmann pins augmented with a below knee non-weight bearing plaster cast. I would remove both and commence rehabilitation after 6 weeks.
- How would you advise the patient as to the likely outcome for this injury and treatment?
These are not common injuries. Fortunately, persistent instability is infrequent. Complications vary and seem to be related to the degree of energy of the injury. Post-traumatic arthritis evident on radiographs is common although the symptom- atic effects of these changes may vary. These may be a result of injury to the joint surface, occult fractures or persistent instability. Open fracture dislocations with associated injuries to the nerves, vessels and related tendons (tibial nerve, posterior tibial artery or posterior tibial tendon) have been associated with worse outcomes.