Complications of Supracondylar Fractures and Their Management

Chapter 9 Complications of Supracondylar Fractures and Their Management





Background/aetiology


The incidence of vascular injuries following supracondylar fractures varies between 5% and 35%.1,2 In addition, patients may also suffer from vascular compromise, which can range from an absent or weak pulse to a frankly ischaemic limb.


Appreciation of the potential range and severity of vascular injuries following supracondylar fractures is essential if serious complications are to be avoided, and for this reason all patients presenting with supracondylar fractures must have a careful vascular assessment of the limb with the results documented in the patient record prior to focusing attention on the fracture.


In addition to major vessel injuries, children with supracondylar fractures may develop compartment syndrome of the forearm. Originally described by Volkmann in 1881, the condition is characterized by bleeding and haematoma formation, oedema or a combination of both within the deep compartment of the forearm. The pressure within the affected compartment increases, resulting in muscular fibrosis and neurological damage.


Peripheral nerve injuries occur in 5–15% of supracondylar fractures.3,4 All nerves crossing the elbow may be injured, with the commonest being the median and its anterior interosseous branch. The median nerve is most at risk with posterolaterally displaced fractures, while the radial nerve is more likely to be damaged if displacement is posteromedial. The greater the bony displacement, the greater is the risk of nerve injury. Although most nerves are damaged at the time of the fracture, it is important to appreciate that they are also at risk during surgical treatment. In particular, the ulnar nerve may inadvertently be injured during pin insertion for fracture fixation.


Malunions of the distal humerus are usually described as cubitus varus or cubitus valgus, despite the fact that the majority are three-dimensional, with varus or valgus, flexion or extension and rotational components. The commonest deformity is varus but whether this results from malunion at the fracture site or is the result of growth imbalance is unknown.


Stiffness following paediatric supracondylar fractures is uncommon and myositis ossificans is rare. Usually it is due to malunion with a flexion deformity at the fracture site, resulting in loss of extension or an extension deformity producing loss of flexion. Stiffness as a result of a soft tissue contracture will only occur after prolonged immobilization, and this should be avoided. In addition, it is generally accepted in children that a loss of elbow flexion and extension may progressively improve for at least a year following injury.



Presentation, investigation and treatment options



Vascular injuries


Vascular injuries are potentially catastrophic complications of supracondylar fractures. As such, any child presenting with a supracondylar fracture must undergo a careful vascular assessment prior to consideration of the bony injury. Presentations may include a diminished or absent pulse, pain on passive flexion/extension of the long flexors to the fingers, or a frankly ischaemic limb. The arterial injury itself can vary from a complete transection of the artery, an intimal tear or compression of the vessel. In addition, there is frequently damage to the venous drainage system.


Compartment syndrome occurs as a direct result of an increase in pressure within the closed compartments of the forearm. It results from disruption of the venous drainage in the presence of continued arterial input. Other factors that also contribute to its development include oedema, haematoma formation and compressive dressings or plaster casts.


Early diagnosis of vascular damage or impending compartment syndrome is essential and requires a thorough clinical examination not only at presentation but routinely thereafter at 15, 30 or 60 min intervals, depending on the severity of the injury.


A palpable, regular, radial pulse is important but may not exclude the diagnosis of compartment syndrome. A better method of assessment is passive and active extension of the fingers. If this is possible and painless it is highly unlikely that the patient has compartment syndrome. Examination of the neurological status of the hand should also be undertaken. Neural tissue as well as muscle is highly sensitive to ischaemia and impairment may be an indicator of ongoing vascular compromise. Conversely, the presence of a pulse together with painless passive finger extension and normal sensation in the fingers effectively excludes a major vascular injury.


Once it has been confirmed that the patient does not have limb-threatening vascular injuries it is appropriate to undertake anteroposterior and lateral radiographs of the elbow. These will reveal the nature of the bony injury and allow formulation of a management plan.


If the hand is obviously ischaemic, the arm should be immediately manipulated and splinted in an extended position. This will often restore the circulation to the hand but if this fails the child should be taken immediately to the operating room for closed reduction and pinning. The role of arteriography is controversial.5,6 While plainly any information about the vascular status is helpful, undertaking the technique should not lead to undue delay with treatment. The rationale is that this is an emergency situation and, if the circulation does not return following reduction and pinning of the fracture, exposure of the brachial vessels should be performed. If the artery is trapped between bony fragments then the fixation should be taken down and the artery liberated. If the artery is crushed, transacted or has an intimal tear, reconstruction will be required, usually with help from a vascular or micro trained surgeon. In this situation it is also important to perform a fasciotomy of the deep fascia of the forearm, particularly if there has been significant ischaemia time.



The management of a limb that is initially ischaemic but becomes viable following reduction and internal fixation, or of a viable limb with a ‘deficient pulse’, is less controversial. In the absence of a radial pulse, but the presence of pink fingers with good capillary return and pain-free, passive and active finger movements, most clinicians would manage the patient conservatively, resting the arm in a splint at 20–30° of extension. If the pulse fails to return over the next 48–72 h, then an arteriogram should be performed, with further management being determined by the results of the investigation.


The initial symptoms of compartment syndrome are often subtle, or missed completely, resulting in a delay in diagnosis and treatment. The increase in pressure within the closed compartment ultimately results in anoxia of soft tissues, particularly muscle and nerve. Diagnosis is based on clinical awareness and should be made before the patient has severe pain, particularly on passive and active movement of the long flexor and extensor finger tendons. Other findings include paraesthesia and loss of capillary return to the finger tips. Loss of the radial/ulna pulse is frequently a late finding.


Treatment should be prompt, with elevation of the affected extremity and mobilization of the fingers, as appropriate. Any constrictive bandages should be removed. If clinical doubt exists, many clinicians undertake urgent pressure measurements within the flexor compartment. Several techniques have been described and there are now a number of propriety instruments that allow this to be undertaken. Controversy still exists, however, regarding the pressure that can be accepted before fasciotomy should be performed. Generally, if the pressure exceeds 30–35 mmHg, or if it is within 30 mmHg of the patient’s diastolic pressure, an emergency fasciotomy should be undertaken. If, however, facilities are not available to measure compartment pressure and clinical concern persists, an urgent fasciotomy should be performed.





Malunion


Cubitus varus or valgus is assessed by measuring the carrying angle of the arm. This is the angle created by the medial border of the fully supinated forearm and the medial border of the humerus when the elbow is extended (Fig. 9.1). The angle typically varies between the sexes, with the normal range lying between 6° and 12°. It is generally greater in female than male patients and is best assessed by comparison with the contralateral side. In addition, as the normal elbow extends, the carrying angle increases, i.e. becomes more valgus. With malunions, however, hyperextension tends to accentuate a cubitus varus deformity, while a flexion contracture can create the appearance of cubitus valgus. Measurement of rotational deformity is more difficult but can be assessed by asking the child to bend forward such that the thoracolumbar spine is parallel to the ground. Each arm is then placed in turn behind the patient’s back and rotation measured as the angle between the forearm and the patient’s thoracolumbar spine when the arm is maximally rotated.



Fortunately, there are few if any symptoms or functional limitations as a result of cubitus varus or cubitus valgus deformity. The principal concern is cosmesis. Occasionally cubitus valgus may be associated with a flexion contracture and in extreme cases the patient may also complain of ulnar nerve symptoms. Conversely in cubitus varus flexion may be limited and occasionally symptoms of elbow instability are present. Rarely, however, does this loss of flexion or extension result in any deficit in activities of daily living.


Unfortunately, there is little potential for angular malunion of the distal humerus to remodel and, as such, the best treatment is prevention. Mild degrees of cubitus valgus and varus should be treated by simple reassurance. However, if the deformity is severe and there are significant cosmetic concerns or any functional restriction. surgical reconstruction should be undertaken.



Gurkan et al7 described posterior instability of the shoulder in three patients with cubitus varus deformity.


A less commonly reported complication of supracondylar fractures of the humerus in children is the dissolution of a portion of the trochlea at a variable time after fracture (Fig. 9.2). If this defect to the trochlea is severe it will allow migration of the ulnar proximally.8 A similar complication on the lateral side of the elbow was reported by Vocke-Hell et al.9 They noted that this could occur at any time between 1 and 4 years after the fracture and may result in secondary radial head dislocation.



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Sep 8, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Complications of Supracondylar Fractures and Their Management

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