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.

Peripheral nerve injuries

The assessment of the peripheral nerves in a young child with a supracondylar fracture can be difficult owing to the natural reluctance to move the fingers and respond to appropriate testing. Indeed it is often impossible to undertake an adequate neurological examination immediately after injury. Generally, however, as pain reduces and recovery ensues, neurological evaluation becomes possible.

If on examination a nerve palsy is detected, the abnormal sensory and motor findings must be accurately recorded. The majority will be a neuropraxia and will spontaneously improve. In these cases, apart from reassurance and physiotherapy input to prevent contractures, little else is required. If, however, there are no signs of recovery at 3 months, nerve conduction studies should be performed. If these show no evidence of neurological recovery and muscle degeneration is taking place, then exploration of the nerve is indicated. Depending on the surgical findings a nerve release, repair or graft may be required. If, however, nerve conduction studies reveal subclinical recovery then an expectant policy can be adopted.

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.

Figure 9.1 Cubitus varus deformity.

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.

Figure 9.2 Dissolution of a portion of the trochlea.

Stiffness

While it is not unusual for children to have some loss of extension at the elbow after supracondylar fractures, this rarely continues and usually improves with time. By 8 and certainly 12 weeks following the injury it is unusual to identify more than a 10° loss of extension. If, however, a greater loss of movement occurs with satisfactory bony alignment, an active physiotherapy programme should be instigated. This involves gentle stretching in both flexion and extension together with the provision of a night splint to help correct the flexion or extension deformity. With therapy, stiffness generally resolves over a few months. Rarely is an arthrolysis required.

Vascular injury

At the author’s institution, exploration and appropriate surgery to the brachial artery or vein are undertaken as an emergency procedure in the presence of an acute vascular injury. Surgery may involve the release or removal of an obstruction, vascular repair or excision with an interposition graft. Generally the latter lies outside the remit of most orthopaedic surgeons and will require the assistance of a vascular or micro trained surgeon. What is important, however, is compartmental decompression with release of the deep fascia. Following this it is often impossible to do a primary skin closure, and a secondary closure or application of a split skin graft may be required.

Technique 1 – exposure of the neurovascular structures at the front of the elbow

With the patient supine, the arm abducted, the elbow extended and the forearm supinated, an incision is made over the anteromedial aspect of the elbow. This should be angled or stepped as it crosses the anterior elbow crease (Fig. 9.3A). The subcutaneous fat is dissected carefully and the medial cutaneous nerve of the forearm isolated and retracted as appropriate.

Figure 9.3 Anterior approach to the elbow. (A) Skin incision. (B) Major vessels and nerves.

The deep fascia is then opened longitudinally and the median nerve and brachial artery together with its venae comitantes identified; they lie immediately deep to the fascia. These structures are then traced proximally, lying medial to the biceps tendon. Distally the brachial artery lies on the brachialis muscle, bifurcating at the level of the neck of the radius into the radial and ulnar arteries. At the elbow, the median nerve lies just medial to the brachial artery.

Distally the radial artery crosses over the insertion of the pronator teres and the origin of the flexor pollicis longus, ultimately disappearing between the tendons of the abductor and the extensor pollicis brevis. The ulnar artery disappears from the cubital fossa, passing deep to the deep head of the pronator teres and beneath the fibrous arch of the flexor digitorum superficialis. Finally the median nerve exits the cubital fossa, between the two heads of the pronator teres (Fig. 9.3B).

Peripheral nerve injury

The exploration of peripheral nerves around the elbow in children is no different from that in adults. Generally the author would recommend the use of loupe magnification during these procedures. Routine exposures of the ulna, median and radial nerves are described in Chapter 31. Following a supracondylar fracture the approaches are the same.

Operative findings may reveal that the nerve is trapped or compressed and in these circumstances a release must be undertaken. Less commonly, the nerve may have been transected and will require excision of a segment and interposition of a nerve graft. Again this may require more specialist input.

Malunion

Preoperative planning is essential if an osteotomy for malunion is to be undertaken. This involves up-to-date comparative radiographs of both humeri in order to identify the amount of bone resection required to achieve correction of the deformity. Digital imaging and CT scans can also provide additional helpful information.

Cubitus varus is the commonest deformity that occurs following a supracondylar fracture. To correct this, excision of a laterally based wedge of bone from the humerus is required. Once this wedge is closed the deformity is corrected. For valgus deformity the wedge must be medially based. For extension and flexion deformities, volar and dorsal corrections are required. For complex three-dimensional deformities a dome-shaped osteotomy can be performed as this will allow the surgeon to correct all aspects of the deformity without significant loss of bone length.

Fixation of the osteotomy can be undertaken with pins as well as plates and screws. At the author’s institution the latter is more commonly used with the application of a small fragment AO semi-tubular plate (Fig. 9.4). This fixation is supplemented by plaster cast splintage for 3–4 weeks.

Figure 9.4 Fixation of corrective osteotomy.

Surgical correction of cubitus varus and cubitus valgus deformities

The operation is performed under general anaesthesia with the use of a small high tourniquet. A longitudinal skin incision is made over the lateral aspect of the distal humerus. Any obvious vessels are coagulated, and the deep fascia opened, allowing exposure of the lateral edge of the humerus. The intermuscular septum is identified and the radial nerve found and reflected anteriorly. A subperiosteral dissection is then undertaken to expose the anterior and posterior aspects of the humeral shaft. The site for the corrective osteotomy is identified at or slightly proximal to the malunion. It is important when this is being planned that the trochlear notch is not violated, as this may impair subsequent elbow movement. Two retractors are placed around the site of the osteotomy, which is marked. The bone is then excised using a combination of a saw and sharp osteotome. Once the wedge is excised the osteotomy is closed using the medial periosteum as a hinge. The osteotomy is then fixed with a four-hole contoured semi-tubular plate. It is important that the screws do not transgress into the trochlear notch. Fixation is checked by X-ray. It is also an advantage to pre-drill the screws distally prior to sectioning the humerus.

Following routine closure the arm is immobilized with a splint, maintaining the elbow at 90° and the forearm in neutral rotation. The arm is splinted for between 3 and 4 weeks before allowing gradual mobilization. A removable splint is then used for a further 2–3 weeks. Usually the osteotomy has healed by between 6 and 10 weeks.

For cubitus valgus deformities, a similar technique is used on the medial aspect of the arm. During this technique, it is important to identify and protect the ulnar nerve. Indeed, if appropriate an anterior transposition of the nerve can be performed.

For flexion and extension osteotomies a lateral approach can again be used. In this instance, however, the osteotomy is angulated in the anteroposterior rather than the lateromedial plane (Fig. 9.5). Fixation is once more achieved using a plate and screws. As an alternative in very young children the osteotomy can be held with crossed K-wires and external plaster splintage.

Figure 9.5 Methods of corrective osteotomy.

For complex multiplanar deformities a dome osteotomy can be useful. The distal humerus is approached via a posterior incision and the triceps split to expose the distal humerus and malunion site. A dome is marked out and multiple drill holes and a sharp osteotome used to create the osteotomy. As this osteotomy has a curved shape the distal fragment of the humerus can be rotated to ‘dial in’ the appropriate correction. The osteotomy is stabilized with a plate and the arm immobilized as described above.

Stiffness

It is unusual for any child who has suffered a supracondylar fracture to require a secondary procedure to treat stiffness. Usually a course of physiotherapy and ‘skilful neglect’ is all that is required. Certainly it is well accepted that soft tissue tightness will improve with time. If, however, there is a persistent soft tissue flexion or extension contracture in an older child, surgical correction may be required. The technique of anterior and posterior capsular release is described in Chapter 29.

Outcomes of treatment for vascular complications

A review of the literature reveals areas of agreement and controversy in the management of a pulseless arm associated with a supracondylar fracture. All clinicians agree that in such a scenario the patient should undergo an immediate reduction and fixation of the fracture, usually with K-wires. Thereafter, the arm should be splinted in extension, further reducing compression of the artery and vein.¹⁰ Elevation of the arm is also useful to prevent oedema. In the majority of patients treated this way the radial pulse is usually restored. Plainly, this situation will require regular monitoring in the early postoperative/injury phase. It is also important to identify any signs of a compartment syndrome.

If the pulse does not return, the management options vary. Some clinicians, predominantly from the United States, advocate emergency exploration of the brachial artery. Authors report finding arterial entrapment and in some cases intimal tears often needing a vascular graft.^11–13 In most patients repairs remain patent, although a progressive postoperative deterioration in circulatory status has been seen 24–36 h after surgery in a small number of cases. This group required further investigation and surgery.

In contrast, the majority of orthopaedic surgeons in the United Kingdom faced with the same scenario would manage the arm conservatively, provided that following reduction of the fracture the hand remains pink and well perfused, and passive movement of the fingers is pain free. The patient would undergo regular review with the expectation that as the swelling subsides the circulation will be restored.¹⁴ In this situation further investigation, specifically pressure monitoring, duplex scanning and magnetic resonance angiography, will enable the clinician to confirm that there is no surgically treatable cause for the absent pulse.

There is no doubt, however, that recovery following severe upper limb ischaemia is limited. Motor recovery does not take place, leaving the patient with significant permanent contractures. Although some degree of sensory recovery may occur, it can take between 6 and 12 months to maximize.¹⁵

Compartment syndrome was noted by Blakemore et al¹⁶ in three out of a series of 33 children, all of whom had displaced extension type supracondylar fractures. This gives an incidence for this complication of 7%. Fasciectomy resulted in a satisfactory outcome in all cases. Ramachandran et al¹⁷ identified 11 patients with this condition, 10 of whom presented with severe swelling around the elbow. In addition, for one reason or another all had surgery delayed by an average of 24 h. Interestingly, all patients presented with low-energy injuries and an intact radial pulse. The authors concluded that significant swelling at presentation and delay to fracture reduction were warning signs for the development of this dangerous complication.

Outcomes of treatment following nerve injury

The incidence of nerve injuries following supracondylar fractures varies from 5% to 15%. Although all of the nerves crossing the elbow may be injured, the most commonly reported are the median and anterior interosseous nerves. Injury can occur with all types of supracondylar fracture but are more common in cases with posterolateral displacement.¹⁸

The next most commonly involved nerves are the radial and posterior interosseous, which are injured in fractures with posteromedial displacement. Injuries to the ulnar nerve may also occur but usually follow percutaneous K-wire fracture fixation rather than as a direct result of the fracture. They occur in 5% of cases.¹⁹

With regard to management, most appear to be a neuropraxia and resolve relatively quickly. Indeed, a significant number referred for more specialist treatment also seem to improve with time. The usual period to full recovery is 2–3 months.

For those who do not recover within that time period, exploration is required. Generally this is undertaken between 3 and 6 months following the injury. The findings at exploration may include bony entrapment, scarring, neuroma formation and complete nerve transection. In the majority of reported cases neurolysis is the commonest procedure undertaken, generally with a good outcome. Some patients do, however, ultimately require exploration and neurolysis and occasionally excision of neuroma and nerve grafting.²⁰ If these techniques are unsuccessful at restoring function, tendon transfers may be required.

It is important to appreciate that while most nerve injuries around the elbow ultimately become obvious clinically, injuries to the anterior interosseous nerve may be less apparent. This is because the anterior interosseous nerve has only motor fibres and if specific testing for the nerve is not undertaken the injury may not be recognized. Fortunately in the majority of cases the nerve spontaneously recovers.

Ulnar nerve injuries that become apparent after supracondylar fracture fixation require urgent treatment. This initially involves removal or repositioning of fixation wires after, which recovery has been reported to occur relatively quickly.²¹ If this is not the case, however, exploration and decompression or rarely reconstruction of the ulna nerve may be required.

Injury, most frequently to the ulnar nerve, may also occur as a late complication of supracondylar malunion. It results in part from an increase in the carrying angle, but also from deformities of the cubital tunnel that comprise a dysplastic trochlea, medial shift of the ulna and deformity of the medial epicondyle. If symptoms are severe, surgery is indicated with decompression of the nerve, release of fibrous bands and anterior transposition. In addition, with marked malunion deformities and ulnar nerve symptoms a corrective osteotomy should also be considered. Finally, the nerve can become unstable and sublux or dislocate out of the cubital tunnel on elbow flexion. If this causes pain and discomfort, treatment involves either a corrective valgus osteotomy of the distal humerus or anterior transposition and stabilization of the nerve.

Outcome of procedures to correct bony deformities

Several reports clearly show that fractures treated by immediate fixation, particularly K-wires, result in fewer and milder cases of cubitus varus deformity when compared to other treatment techniques.^22,23 This minimizes the cosmetic deformity that many patients find unacceptable and reduces the need for corrective surgery. In addition to tardy ulnar nerve palsy seen in cubitus valgus deformity, instability of the ulnar nerve has also been reported.^24,25 The latter is often associated with an unstable or snapping medial triceps.

Posterolateral rotatory instability has been described as a complication of long-standing varus deformity. Following an initial case report by Abe et al,²⁶ O’Driscoll et al²⁷ described 24 cases (25 limbs) of this condition, which occurred two to three decades after the original injury. All patients presented with lateral elbow pain and recurrent instability. The average varus deformity was 15°. The explanation for this complication was stated to be repetitive external rotation torque on the ulna, resulting in stretching of the lateral collateral ligament complex. Surgical treatment included a supracondylar valgus osteotomy and transposition of a portion of the medial head of the triceps to the lateral aspect of the olecranon. Although this was generally successful, two patients in this series continued to have snapping of the medial head of the triceps.

A biomechanical analysis of the effect of distal humeral varus deformity on strain to the lateral ulna collateral ligament was undertaken by Beuerlein et al.²⁸ Using fresh frozen cadaveric elbow joints they measured strain in the ligament while stressing the ulnar humeral joint in several positions of varus. They confirmed that increasing deformity increased strain on the lateral ulnar collateral ligament.

Correction of the deformity is achieved by performing a closing valgus wedge osteotomy. Bellemore et al²⁹ from Sydney reported their results in 32 patients over a 10-year period. Half of these underwent the technique described by French³⁰ to fix the osteotomy. This involved the insertion of a screw either side of the osteotomy with a figure-of-eight wire around the screws to provide compression at the osteotomy site. Overall, apart from an unsightly scar in four cases, they reported a significant improvement in cosmesis, within 5° of the contralateral side. There were, however, some failures due to inadequate osteotomy fixation. These occurred principally in the group fixed by K-wires alone. Range of motion was generally preserved and, overall, they recommended this technique. The problems with K-wire fixation have also been reported by Rang,³¹ who in a series of 20 patients experienced loss of fixation, infection, nerve palsy and an aneurysm of the brachial artery. Oppenheim et al³² from the United States reported their results of 45 osteotomies performed in 43 children with an average follow-up of years. While good to excellent results were obtained in most patients, unsatisfactory results were seen in 12. There was also a significant complication rate of 24%, which included neuropraxia, sepsis and cosmetically unacceptable scarring. It should be noted again that in this series fixation was undertaken by threaded Steinmann pins alone.

A variation on this technique was described by DeRosa and Graziano in 1987,³³ when they reported a step-cut osteotomy that allowed fixation by a single screw. In their series of 11 patients, they were able to obtain an average correction of 28.4°, leaving a carrying angle of 9.3° in most patients. There were no complications.

New techniques of osteotomy fixing include the use of plates and external fixation.³⁴ Devnani in 1997³⁵ reported his results in nine children undergoing osteotomies that were internally fixed with a two-hole plate. Generally the results were good, with no loss of correction due to implant failure. The implant was usually removed 12 months after surgery. Many clinicians would now use a four-hole plate.

In 1997 Matsushita and Nagano³⁶ from Japan reported the technique of an arc or dome osteotomy. This technique allowed simultaneous correction of both the angulatory deformity and any lateral shift. In 12 patients followed for 28 months the average carrying angle was corrected from 22° of varus to 6° of valgus with no complications. Movements were also well maintained. Finally, Usui et al³⁷ from Japan described a three-dimensional corrective osteotomy for the treatment of cubital varus. This osteotomy, which is again principally lateral based, also allows correction of any hyperextension or internal rotation deformity.