Injuries to the Femur
Femoral fractures are relatively uncommon in sport, but come with an associated risk of morbidity and 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 significant risk of blood loss and potential for haemorrhagic shock. Immobilisation and appropriate resuscitation are therefore important.
Injuries to the Thigh
Thigh contusions are a very common injury in sport, especially in contact and collision sports. Brooks et al (2005) demonstrated high incidence rates 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 degrees of severity. While the majority recover spontaneously without complications, there have been reported cases of compartment syndrome following blunt trauma to the thigh in sport (Colosimo & Ireland, 1992).
Injuries to the Knee
Knee Dislocation and Multi-ligament 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 absent). While documented knee dislocations are uncommon in sport, multi-ligament injuries are not, and a dislocated knee may spontaneously reduce at the time of injury. Multi-ligament injuries should therefore be managed as dislocations until proven otherwise. Multiple ligament knee injuries are commonly associated with neurovascular complications such as popliteal artery, common peroneal nerve and 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 associated popliteal artery injury 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 50º of hyperextension resulted in a rupture of the popliteal artery (Kennedy, 1963).
The consequences of delayed recognition of popliteal artery compromise are significant. In 1977, Green and Allen reported an 86% amputation rate when popliteal artery circulation was not restored within 8 hours, with 89% salvage rate when restored within 8 hours.
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 correct preparation of the player for transfer to definitive care with appropriate documentation and communication with the receiving hospital.
Serial examination should be performed at least every 4 to 6 hours for 48 hours to monitor for late-developing complications such as compartment syndrome and popliteal artery thrombosis (Wascher, 2000). Nicandri et al (2010) presented data indicating that a single initial examination of pulses is not adequate to rule out a surgically significant vascular injury. They present a case report of a player who initially presented with normal pulse examinations but later developed distal ischemia that led to limb amputation. They propose that by using an evidence-based protocol, the incidence of a delay in diagnosis can be reduced. Evidence-based protocols include an 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 a minimum 24h.
Injury to the Peroneal Nerve
The common peroneal is the most frequently injured peripheral nerve with a 25% to 35% incidence associated with knee dislocation (Johnson et al, 2008). The mechanism of injury to the common peroneal is usually a varus stress and are therefore, commonly associated with posterolateral corner knee injuries (LaPrade and Terry, 1997). The 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 and sensory deficits. Motor function of the superficial peroneal nerve is tested by active foot eversion. Motor 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 common than injury 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. Sensation changes on the dorsum of the foot may be present.
Neurovascular injuries are commonly associated with knee dislocation and multi-ligament knee injuries. It is vital that the early assessment and management of these injuries is appropriate to reduce the potential for significant consequences.