Spezielle Probleme und Sp�tfolgen nach OSG-Fraktur

Fixation of anterolateral distal tibial fractures: the anterior malleolus

OBJECTIVE

The anterior tibial rim with the anterolateral tibial tubercle provides attachment to the anterior tibiofibular syndesmosis. It may be considered an anterior or "fourth" malleolus. Fixation of a displaced anterior tibial fragment in the treatment of malleolar fractures aims at providing a bone-to-bone fixation of the anterior tibiofibular ligament and restoring the integrity of the tibial incisura.

INDICATIONS

Displaced intra-articular fragments of the anterior tibia; fractures involving the tibial incisura; fractures with intercalary fragments; impaction of the anterior tibial plafond; syndesmotic avulsions producing instability or preventing reduction of the distal fibula into the tibial incisura.

CONTRAINDICATIONS

Critical local soft tissues preventing an anterolateral approach; missing consent to surgery by the patient; overall critical general condition preventing surgery to the extremities.

SURGICAL TECHNIQUE

Anterolateral approach over the tibial tubercle. Identification and mobilization of the anterior tibial fragment without dissecting the anterior syndesmosis. Reduction of the anterior tibial fragment with a pointed reduction clamp. Fixation of extra-articular avulsion fractures (type 1) with suture anchor. Screw fixation of larger fragments involving the joint surface and incisura (type 2). Disimpaction, realignment of the joint surface, bone grafting as needed and plate fixation of impaction fractures of the anterolateral tibial plafond (type 3).

POSTOPERATIVE MANAGEMENT

Mobilization with partial weight bearing (15-20 kg) in a special boot (ankle foot orthosis) or cast for 6-8 weeks depending on the overall malleolar fracture pattern, bone quality and patient compliance.

RESULTS

Few studies report the results of anterior tibial fractures in adults. Failure to fix displaced fragments frequently leads to nonunions. Overlooked Chaput fractures have been reported to result in malpositioning of the distal fibula in the tibial incisura leading to incongruity of the ankle mortise requiring revision surgery. Secondary avascular necrosis of the anterolateral tibial plafond may develop after joint impaction.

[Minimally invasive fixation of distal fibular fractures with intramedullary nailing]

OBJECTIVE

Minimally invasive osteosynthesis of distal fibula fractures serves as a biomechanically stable and soft-tissue-friendly fixation method in the case of an unstable fracture, poor bone quality, and/or critical soft tissue conditions with restoration of the length, axis and rotation of the distal fibula as well as stabilization of the ankle mortise. The goal is to reduce and stabilize the distal fibular fracture in a quick and stable manner that protects the soft tissues in ankle fractures.

INDICATIONS

Unstable malleolar fractures and fracture dislocations; fibular fractures in combination with distal tibia fractures; critical soft tissue conditions around the ankle.

CONTRAINDICATIONS

No consent to surgery by the patient. Overall critical (life-threatening) general condition preventing surgery to the extremities. Very narrow medullary canal of the fibula (less than 3 mm, depending on the implant).

SURGICAL TECHNIQUE

Percutaneous placement of a guidewire into the distal fibular tip, opening the medullary canal and drilling the medullary canal in the distal fragment. Reduction of the axis by introduction of the fibular nail, with additional percutaneous use of reduction clamps for restoration of fibular length and rotation, if necessary. Placement of distal locking screws over the targeting device while maintaining rotation and length, in addition proximal static locking is mandatory to maintain the length of the fibula. In case of residual syndesmotic instability after fracture fixation, syndesmotic screws are inserted through the fibular nail via the aiming device.

POSTOPERATIVE MANAGEMENT

Following surgery, rest and elevation of the injured leg, and local cooling are indicated. Subsequently, mobilization with partial weight bearing (15-20 kg) in an ankle foot orthosis or plaster/cast for 6 weeks.

RESULTS

Minimally invasive fibular fixation with an intramedullary nail results in a significantly lower rate of wound healing complications compared with lateral plating. Reported union rates range from 97.4 to 100% with current nail designs. The quality of reduction and functional outcome is comparable to that after plate fixation. A certain learning curve has to be respected.

[External fixator: temporary fixation and soft tissue management of the ankle]

OBJECTIVE OF SURGERY

Joint-spanning transfixation of the ankle joint aims at mostly temporary retention of the reduction, i.e. restoring length and axial alignment and stabilization of the ankle mortise in highly unstable fractures around the ankle and under critical soft tissue conditions. In selected cases, external fixation serves as an additional stabilization also following completed internal fixation or the fracture can be treated in the external fixator. The goal of surgery is to allow quick soft tissue recovery, prevention of redislocation and stabilization of the ankle and adjacent structures.

INDICATIONS

a) Fractures of the tibial pilon; b) very distal, extra-articular lower leg fractures (without the option for pin positioning in the distal fragment); c) highly unstable malleolar fractures with tendency to subluxation and dislocation fractures; d) critical soft tissue conditions around the ankle; e) dislocation fractures of the talus, Chopart and Lisfranc joints (if necessary with additional transarticular transfixation).

CONTRAINDICATIONS

Missing consent to surgery by the conscious patient, life-threatening general condition by other prioritized injuries.

SURGICAL TECHNIQUE

Percutaneous pin placement of the appropriate caliber into so-called safe zones of the tibia, metatarsus and calcaneus, as needed. Additional transfixation of the Chopart and Lisfranc joints with K‑wires as needed. Fixation of the struts with the foot in a neutral position. Besides consideration of biomechanical principles, pin placement must be done in anticipation of the definitive stabilization and future approaches respecting the anatomical structures while achieving maximum stability and soft tissue protection.

POSTOPERATIVE MANAGEMENT

Following initial transfixation, elevation of the injured leg for soft tissue protection, local cooling and bed rest are indicated. In cases of compartment syndrome and open fractures with temporary soft tissue coverage, second look surgery after 24-72 h is mandatory. For exact fracture analysis and optimal planning of the definitive surgical strategy, the indications for CT imaging should be generously considered. The timing of definitive care depends on the local soft tissue status and the overall condition of the patient.

RESULTS

The presence of a dislocation at the time of the accident represents a negative prognostic factor for ankle fractures. Higher rates of posttraumatic arthrosis are also found in pilon fractures and trimalleolar fractures, direct cartilage damage and rupture of the syndesmosis. In cases of anatomic reconstruction of the mortice and ankle joint congruence, good to excellent results can be achieved in 75-89%.

Early Corrections after Failed Ankle Fracture Fixation

Even minor residual fragment malpositioning after internal fixation of ankle fractures is associated with a worse prognosis. Frequent causes for non-anatomical reduction are fibular shortening due to comminuted fractures or poor bone quality, translational or rotational malpositioning of the distal fibula within the tibial incisura with unstable syndesmosis injuries, and inadequately addressed bony avulsions of the tibiofibular syndesmosis. After operative treatment of fracture dislocations with syndesmotic fixation, in case of complex fracture pathoanatomy, and with suspected non-anatomic reduction in postoperative radiographs, computed tomography imaging of both ankles should be performed. Correction of relevant malreductions should be performed as early as possible in order to speed up rehabilitation and to avoid late sequelae due to a load shift or instability in a weight-bearing joint.

[Operative treatment of pronation fracture--dislocations of the ankle]

OBJECTIVE

Early reduction of the dislocation and anatomic reconstruction of axial alignment, ankle mortise and articular congruity with special focus on syndesmotic stability.

INDICATIONS

Fracture-dislocations resulting from pronation injuries to the ankle with a highly incongruent and unstable mortise and either considerable internal pressure on the soft tissues by the displaced fragments or open soft tissue damage.

CONTRAINDICATIONS

General contraindications to surgery: closed reduction and cast immobilization or external fixation.

SURGICAL TECHNIQUE

Early preoperative closed reduction of complete dislocations is achieved through longitudinal traction and movements contrary to the original fracture mechanism. A cast or joint-spanning external fixator is applied temporarily. Ideally, definite anatomic reduction of the posterior tibial fragment, the distal fibula and medial malleolus and stable internal fixation is achieved within the first hours after the injury. Congruity of the ankle mortise and syndesmotic stability is controlled intraoperatively and a syndesmotic screw is inserted if necessary. In these cases, the correct positioning of the distal fibula within the tibial incisura is verified with three-dimensional fluoroscopy or postoperative computed tomography scanning.

POSTOPERATIVE MANAGEMENT

Early range of motion exercises of the ankle and subtalar joints are initiated the second postoperative day or after soft tissue consolidation and removal of the external fixation. Patients are mobilized with partial weight bearing (20 kg) in a cast or special boot for 6 weeks postoperatively. The syndesmotic screw is then removed in most cases and weight-bearing is rapidly increased.

RESULTS

The presence of a dislocation at the time of injury represents a negative prognostic factor in malleolar fractures. Higher rates of posttraumatic arthritis are also observed with trimalleolar fracures, especially fractures of the posterior tibial rim, cartilage damage, and syndesmotic disruption. Irrespective of the fracture classsification, good to excellent results can be obtained in 75-89% of cases with anatomic reconstruction of the ankle mortise and the articular surfaces. Proper reduction of the distal fibula into the tibial incisura is of utmost importance in cases of frank syndesmotic diastasis.