Tibial and Fibula Fractures (Including Horse-rider's Knee)

Of the two bones of the lower leg, the tibia is the only weight-bearing bone. Fractures of the tibia are often associated with fracture of the fibula. The skin and subcutaneous tissue over the anterior and medial tibia are very thin and therefore lower leg fractures are often open. Even in closed fractures, the soft tissue can become compromised. The fibula is well covered by soft tissue except at the lateral malleolus.¹

• Tibial fractures in adults are usually caused by direct blows or falls onto the tibial shaft.
• Spiral fractures of the tibia and fibula may be caused by violent twisting injuries, usually from contact sports.
• Displaced fractures usually involve both the tibia and fibula.
• Displaced tibial shaft fractures may be complicated by injury to the popliteal artery and compartment syndromes. Fractures of the proximal fibula may be associated with injury to the common peroneal nerve. Distal pulses and sensation should therefore be checked and monitored regularly.
• Diagnosis is usually obvious with deformity, localised swelling and tenderness. All wounds near to the fracture site suggest compound injuries.
• X-rays: must show the whole length of the tibia and fibula. Check for associated injuries to the knee and ankle.
• Prognosis is generally good but is dependent on degree of soft-tissue injury and bony comminution.
• The prognosis is good for isolated fibula fractures.

Potential complications include:¹

• Neurovascular compromise: popliteal artery injury is very serious and easily missed
• Compartment syndrome
• Peroneal nerve injury:
  • The common peroneal nerve crosses the fibular neck and is susceptible to injury from a fibular neck fracture, the pressure of a splint or during surgical repair.
  • Peroneal nerve injury may result in foot drop and sensation abnormalities.
• Infection
• Gangrene
• Skin loss
• Osteomyelitis
• Delayed union, non-union, malunion
• Amputation
• Arthritis
• Fat embolism

• Those at risk include army recruits, runners and ballet dancers. There has often been an increase in intensity of training in the weeks or months leading up to the injury.
• Often not initially evident on x-ray but a bone scan will show increased bone activity at the site of the fracture. Later x-rays may show periosteal new bone, with a small transverse defect in the bone cortex.
• Presents with pain in the front of the leg. Pain is initially after exercise, then during and after exercise and then pain without exercise. Examination may reveal warmth, local tenderness and swelling.
• Management is to avoid the stressful physical activity for 8-10 weeks and then a gradual return to the activity.
• Persisting symptoms suggestive of stress fracture require orthopaedic follow up.

• Frontal impact at the level of the proximal tibio-fibular joint may result in posterior dislocation of the fibular head.
• Reduction usually requires manipulation under anaesthesia.

• Isolated fractures of the tibia are unusual except in children.
• There is a risk that the intact fibula will act to hold the fragments apart and so increase the likelihood of non-union, in which case the fibula may need to be divided.

Management

• Undisplaced transverse tibial shaft fractures:
  • Analgesia and immobilisation in a long leg POP back-slab.
  • Spiral and oblique fractures: immobilised in a long leg POP backslab. They are potentially unstable.
  • Refer to the orthopaedic team for admission.
• Displaced fractures:
  • Give IV analgesia, immobilise in a long leg POP backslab and refer to the orthopaedic team. May require manipulation under anaesthesia or closed intramedullary nailing.
  • Badly comminuted or segmental fractures may require open reduction and internal fixation.
  • Urgent orthopaedic referral is required for any case of suspected vascular injury, sensory deficit or gross swelling.
• Compound fractures:
  • Treatment includes irrigation of the wound with saline, cover the wound with a moist sterile dressing, give intravenous antibiotics (e.g. cefuroxime but depends on local guidelines) and tetanus toxoid if indicated.
  • Refer to the orthopaedic team for urgent wound cleaning, debridement and fixation with closed intramedullary nailing or external fixation.

• Undisplaced spiral fractures of the tibial shaft in children under 7 years old often follow minimal trauma and may not be visible on initial x-ray.³
• Can be difficult to diagnose but should be suspected whenever a child presents with a limp or fails to bear weight on the leg.
• Treatment consists of immobilisation for a few weeks to protect the limb and to relieve pain.
• Subperiosteal bone formation is usually apparent on x-rays by two weeks.

• These occur in combination with a tibial fracture or in isolation as a result of a direct blow or from twisting injuries.
• Proximal fibular injuries may cause damage to the common peroneal nerve, causing weakness of ankle dorsiflexion and reduced sensation of the lateral aspect of the forefoot.

Management

• Undisplaced proximal or fibular shaft fractures: analgesia and elevation. Support in a tubigrip or padded bandage.
• If unable to weight-bear, use a below knee POP for comfort with crutches until weight-bearing is possible. Arrange orthopaedic follow-up.
• Comminuted or displaced fractures: refer to the orthopaedic team.

• Stress fractures of the fibula are relatively common, typically affecting the fibular neck of military recruits and athletes following vigorous training.
• Treat symptomatically with rest and analgesia.

• Transmitted forces may fracture the proximal fibula following an ankle injury.
• This usually involves fracture of the medial malleolus and fracture of the proximal fibula or fibular shaft.
• It implies damage to the distal tibio-fibular syndesmosis.
• Examine the proximal fibula in all ankle injuries and x-ray if locally tender.