High-energy distal femur fractures: an update

Abstract

Distal femur fractures follow a typical bimodal distribution between higher energy fractures affecting a younger population and lower energy fractures affecting a more elderly population. This article focuses on the former and the unique challenges they pose to the treating orthopaedic surgeon. Starting with initial assessment and early management there is discussion regarding appropriate investigation and classification of these injuries before moving on to discuss different techniques in their surgical management. These are complex injuries with potential for significant lifelong morbidity and as such the definitive management should be meticulously planned with appropriate input from experienced clinicians as well as other specialties and disciplines. There will and should be differences of opinion regarding ‘the best’ surgical technique for fixing these fractures, but the aim should be to restore pain-free function to the patient and limit the long-term sequelae of their injury.

Introduction

Distal femur fractures come in all shapes and sizes and can be broadly separated according to mechanism.

Low-energy distal femur fractures in the elderly should be managed in accordance with fragility fracture guidelines where the aim should be early restoration of weight-bearing in conjunction with optimal medical care.

Peri-prosthetic distal femur fractures should be discussed with lower-limb arthroplasty surgeons to ensure appropriate consideration and management of the in-situ implants.

Often there is overlap between these two groups and a multi-disciplinary approach is key to ensuring good outcomes in this complex subset of patients.

First we focus on high-energy distal femur fractures, covering the initial approach, diagnosis and classification as well as options in management. High-energy injuries encompass those where significant amounts of kinetic energy have been transferred to the patient. Fortunately in the UK, gunshot wounds and explosive injuries are rare, but road traffic collisions and falls from height are not and trauma surgeons should be comfortable in their management.

Initial assessment: the trauma bay

High-energy injuries always require thorough primary and secondary surveys to identify and treat more life-threatening injuries. In this acute stage the extremity injuries take a lower priority except in the case of catastrophic external haemorrhage which may require immediate life-saving intervention to prevent death through blood loss. The current ‘horizontal’ approach to trauma care does however allow concurrent activity that should not be ignored. Manual inline traction of a visibly deformed lower limb is unlikely to interfere with assessment of airway, breathing and circulation, but it will help stabilize a long bone fracture and as such aid with blood loss, pain and the physiological response to trauma. It also gives valuable information regarding the neurovascular status of the foot distal to the injury to the clinician holding the foot.

The presence of an orthopaedic specialist in the early stages of a trauma call cannot be underestimated for this reason. High-energy trauma patients are often intubated and ventilated for humanitarian reasons as the most effective means of controlling their pain and limiting further pain during early interventions and investigations. Once this has happened, neurological assessment of the limb distal to any injury is impossible. Being present for the patient handover also grants access to useful pre-hospital information that may otherwise be missed and can often be vital in helping the senior decision-makers settle on a management plan in the following day’s trauma meeting.

Soft tissues

Once the patient is stable attention can be turned to the soft tissues to identify the presence of open fractures with or without joint communication, compartment syndrome and any associated closed neurovascular injury. Open fractures should be managed in accordance with British Orthopaedic Association/British Association of Plastic, Reconstructive and Aesthetic Surgeons (BOA/BAPRAS) guidelines ensuring early antibiotics if not already administered in the pre-hospital setting and subsequent combined orthoplastic care. Wounds should be photographed with consent where possible on an appropriate imaging device. Gross contamination should be removed/cleaned prior to reducing any protruding bone remembering that volume of liquid is more important than sterility in this setting. Attempts should be made to reduce any associated dislocations in appropriately analgesed/anaesthetized patients and documentation of neurovascular status pre- and post-procedure must be completed. The timing of imaging can be contentious. Many (including the author) would consider the above interventions to be first aid and as such appropriate to be done in the trauma bay prior to any imaging. If X-ray can be done immediately then it may be reasonable to gather additional information first. The patient and their physiological status should aid decision-making. Unstable patients require early interventions to improve their stability, not investigations. Equally, grossly unstable limbs require early splinting to aid soft tissue resuscitation.

Initial management

Stabilizing a high-energy distal femur fracture will decompress neurovascular structures, provide a suitable environment for clot formation (thereby reducing blood loss) and crucially provide pain relief. All these factors combined will help reduce the physiological response to major trauma. The deforming forces across these fractures will tend to shorten (quadriceps and hamstrings) and extend/apex posterior (gastrocnemius) the fracture. The relationship of the adductor tubercle to the fracture can lead to varus or valgus deformity. Application of simple inline traction will go some way to overcoming these forces and serve to stabilize the limb. The majority of emergency departments will still use Thomas splints. Many pre-hospital practitioners will carry the Kendrick Traction Device Splint due to its light weight and ease of storage. These are entirely appropriate in the pre-hospital setting, but the webbing straps will quickly cause skin necrosis and should be exchanged for a properly padded Thomas splint as soon as practicable. Once the patient has been transferred to a ward/intensive therapy unit (ITU) bed this can be exchanged to skin traction to reduce the risk of pressure sores. Do not rely on the ward having a subject matter expert regarding skin traction readily available, it is the responsibility of the senior orthopaedic clinician present to ensure safe and appropriate traction is applied. Realistically, Hamilton–Russell skin traction is purely aspirational in the modern UK trauma centre. Persuading non-trauma experienced clinical teams to raise the foot end of the bed and hang 10% of the patient’s bodyweight off some skin traction will often pose a great test to one’s non-technical skills.

High-energy fractures in general warrant a high level of suspicion for associated vascular injury, this is particularly the case in the presence of a knee joint dislocation. Taking a pragmatic approach, all these injuries are going to have a CT scan. The addition of contrast and arterial phase scanning will identify any arterial injury including intimal flaps as well as providing information regarding the proximity of the femoral artery to any medial spikes of bone. Should any free tissue transfer be required for soft tissue coverage CT angiography will give sufficient information to plan anastomoses. If vascular injury is identified the patient should immediately be discussed with a surgeon able to perform vascular repair. As per BOAST, the ischaemic limb should be revascularized within 4 hours. There does not appear to be any difference in outcome regarding the sequence of vascular/bony repair in these patients, ^, but a spanning external fixator should provide stability to any definitive vascular repair, stabilize the fracture/joint and allow concomitant fasciotomies to be performed.

Early total care versus damage control orthopaedics

This article is focused on distal femur fractures in the context of major trauma; as such damage control orthopaedics may well be indicated while other life-threatening conditions are treated. Application of an external fixator in this setting will almost always have to span the knee joint. If applying a spanning external fixator across the knee ( Figure 1 ) consideration should be made regarding pin placement. Laterally placed femoral pins will make rolling a patient on ITU difficult but may be necessary in certain situations. Bi-planar frames will afford greater stability but are more time consuming to apply. Adjustments to almost every aspect of the construct can be made outside of the operating theatre, but that may be your only chance at getting the half pins right.