Lower Limb

Injuries to the Femur

Femoral fractures are relatively uncommon in sport but have an associated risk of morbidity and occasionally mortality. A significant force is required, and fractures may occur at the femoral neck, shaft or distal femur. Fractures may be open or closed, with a risk of haemorrhagic shock. Fracture immobilisation and appropriate resuscitation are important.

Injuries to the Thigh

Thigh contusions are a very common injury, especially in contact and collision sports. Brooks et al (2005) demonstrated a high incidence of thigh haematoma in rugby union during match play (8 injuries/1000hrs). Anterior thigh injury is most common and blunt trauma to the quadriceps muscle group can result in a contusion of varying severity. While the majority recover spontaneously without complications, cases of compartment syndrome have been reported following blunt trauma to the thigh in sport (Colosimo & Ireland, 1992).

Injuries to the Knee

Knee Dislocation and Multiligament Injury

Knee ligament injuries are a very common injury in sport, especially in contact and collision sport. Brooks et al (2005) demonstrated high incidence rates of medial collateral ligament sprains in rugby union during match play (3.1 injuries/1000hrs) and a high severity rate with anterior cruciate ligament injuries (258 mean days of absence from sport.). While documented knee dislocations are uncommon in sport, multiligament injuries are not, and a dislocated knee may spontaneously reduce at the time of injury. Multiligament injuries should therefore be managed as dislocations until proven otherwise. Multiligament knee injuries are also commonly associated with neurovascular complications such as; popliteal artery, common peroneal nerve or tibial nerve injuries (Johnson et al, 2008) and good pre-hospital management is vital.

Injury to the Popliteal Artery

Studies have shown the incidence of popliteal artery injury associated with a dislocated knee to be 32% (Treiman et al, 1992). The popliteal artery is susceptible to injury as it is tethered proximally as it emerges from the adductor hiatus and distally at the tendinous arch of the soleus. An anterior knee dislocation mechanism usually produces a stretching injury of the artery with small intimal tears. Posterior dislocations are more likely to result in the complete disruption of the artery. Cadaveric studies found that over 50º of hyperextension resulted in a rupture of the popliteal artery (Kennedy, 1963).

A brief history to understand the mechanism of the injury should be taken. The knee may have no deformity due to spontaneous reduction. An assessment of the neurovascular status should be made and documented. If there is an obvious deformity at the knee joint it should be reduced immediately with adequate analgesia, using longitudinal traction. Assessment of the neurovascular status must be carried out before and after reduction. The limb should be splinted and the player prepared for transfer to definitive care with appropriate documentation and communication with the receiving hospital.

Serial examinations should be performed at least every 4 to 6 hours for 48 hours to look for late complications such as compartment syndrome or popliteal artery thrombosis (Wascher, 2000). Nicandri et al (2010) presented data indicating that a single initial examination of pulses was not adequate to rule out a surgically significant vascular injury. They published a case report of a player who initially presented with normal pulse examinations but later developed distal ischemia that led to limb amputation. They proposed that by using an evidence-based protocol, the incidence of delay in vascular injury diagnosis could be reduced. Evidence-based protocols include initial palpation of pedal pulses and at least one of the following; angiography, duplex ultrasonography, ankle brachial indices or repeated physician documented physical examination over an observation period of at least 24 hours.

Injury to the Peroneal Nerve

The common peroneal is the most frequently injured peripheral nerve with a 25-35% incidence associated with knee dislocation (Johnson et al, 2008). The common peroneal nerve is usually  injured when the knee is in a varus stress and is commonly associated with posterolateral corner knee injuries (LaPrade and Terry, 1997). Its superficial location as it wraps around the fibula, together with the relative immobility of the nerve, makes it susceptible to injury.

A neurovascular assessment of the limb should include; peripheral pulses, capillary refill time and if time allows during the secondary survey an assessment for any motor or sensory deficits. Motor function of the superficial peroneal nerve is tested by active foot eversion. Motor function of the deep peroneal nerve is tested by asking the player to dorsiflex the foot and extend the toes. The superficial branch of the common peroneal nerve provides sensation to the lateral aspect of the lower leg and the dorsum of the foot. The deep peroneal branch provides sensory innervation to the first dorsal web space.

Injury to the Tibial Nerve

Tibial nerve injury is much less commonly injured  compared to the common peroneal nerve. Wascher et al (1997) reported 5 cases of tibial nerve injury associated with knee dislocation. Examination of motor function may show full strength in the soleus, gastrocnemius, and biceps femoris, but weakness of tibialis posterior, flexor digitorum longus and flexor hallucis longus and brevis may be present due to their innervation being distal to the knee. Sensory changes on the dorsum of the foot may be present.

Neurovascular injuries are commonly associated with knee dislocation and multiligament knee injuries. It is important that the early assessment and management of these injuries is appropriate to reduce the potential for significant consequences.