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applied with the ankle in plantarflexion; the foot is then steered into inversion or eversion to correct the displacement shown on the X-ray. The reduction is checked by X-ray; nothing short of ‘anatomic’ is acceptable. A below-knee cast is applied (with the foot still in equinus) and this is retained, non- weight-bearing, for 4 weeks. Cast changes after that will allow the foot to be gradually brought up to plantigrade; however, weight-bearing is not permitted until there is evidence of union (8–12 weeks).
If closed reduction fails (which it often does), open reduction is essential; indeed, some would say that all type II fractures should be managed by open reduction and internal fixation without attempting closed treatment. Through an anteromedial incision the fracture is exposed and manipulated into position. Wider access can be obtained by pre-drilling and then osteotomizing the medial malleolus. The fracture reduction is checked by X-ray and the fracture is then fixed with two screws. The osteotomized malleolar fragment is fixed back in position with screws. Postoperatively a below-knee cast is applied; weight-bearing is not permitted until there are signs of union (8–12 weeks).
Type III fracture-dislocations need urgent open reduction and internal fixation. The approach will depend on the fracture pattern and position of displaced fragments. Osteotomy of the medial malleolus might help; the malleolus is pre-drilled for screw fixation and osteotomized and retracted distally without injuring the deltoid ligament. This wide exposure is essential to permit removal of small fragments from the ankle joint and perfect reduction of the displaced talar body under direct vision; even then, it is difficult! The position is checked by X-ray and the fracture is then fixed securely with screws. If there is the slightest doubt about the condition of the skin, the wound is left open and delayed primary closure carried out 5 days later. Postoperatively the foot is splinted and elevated until the swelling subsides; a below-knee cast or splintage boot is then applied, following the same routine as for type II injuries.
DISPLACED FRACTURES OF THE BODY
Fractures through the body of the talus are usually displaced or comminuted and involve the ankle and/ or the talocalcaneal joint; occasionally the fragments are completely dislocated.
Minimal displacement can be accepted; a below-knee, non-weight-bearing cast is applied for 6–8 weeks; this is then replaced by a weight-bearing cast for another 4 weeks.
The small number of horizontal fractures that do not involve the ankle or subtalar joint are treated by closed reduction and cast immobilization (as earlier).
Displaced fractures with dislocation of the adjacent joints should be accurately reduced. In almost
all cases open reduction and internal fixation will be needed (Figure 32.19). An osteotomy of the medial malleolus is useful for adequate exposure of the talus; the malleolus is predrilled before the osteotomy and fixed back into position after the talar fracture has been dealt with. The prognosis for these fractures is poor: there is a considerable incidence of malunion, joint incongruity, avascular necrosis and secondary osteoarthritis of the ankle or talocalcaneal joint.
DISPLACED FRACTURES OF THE HEAD
The main problem is injury to the talonavicular joint. If the fragments are large enough, open reduction and internal fixation with screws is the recommended treatment. If there is much comminution, it may be better simply to excise the smaller fragments. Postoperative immobilization is the same as for other talar fractures.
FRACTURES OF THE TALAR PROCESSES
If the fragment is large enough, open reduction and fixation with K-wires or small screws is advisable. Tiny fragments are left but can be removed later if they become symptomatic.
OSTEOCHONDRAL FRACTURES
These small surface fractures of the dome of the talus usually occur with severe ankle sprains or subtalar dislocations. Most acute lesions can be treated by cast immobilization for 4–6 weeks. Occasionally a displaced fragment is large enough to warrant operative replacement and internal fixation – easier said than done! More often it is separated from its bed and is excised: the exposed bone is then drilled to encourage repair by fibrocartilage.
OPEN FRACTURES
Fractures of the talus are often associated with burst skin wounds. In some cases the fracture becomes ‘open’ when stretched or tented skin starts sloughing. There is a high risk of infection in these wounds and prophylactic antibiotics are advisable.
The injury is treated as an emergency. Under general anaesthesia, the wound is cleaned and debrided and all necrotic tissue is removed. The fracture is then dealt with as for closed injuries, except that the wound is left open and closed by delayed primary suture or skin grafting 5–7 days later, when swelling has subsided and it is certain that there is no infection. The plastic surgeons may have a role to play in providing early cover and closure.
Sometimes, in open injuries, the talus is completely detached and lying in the wound. After adequate debridement and cleansing, the talus should be replaced in the mortise and stabilized, with fixaton. Later definitive fixation is then performed.
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3Complications
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Malunion The importance of accurate reduction |
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has been stressed. Malunion will lead to distortion |
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of the joint surface, limitation of movement and pain |
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TRAUMA |
on weight-bearing. If early follow-up X-rays show |
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redisplacement of the fragments, a further attempt at |
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reduction is justified. Persistent malunion predisposes |
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to osteoarthritis. |
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Avascular necrosis Avascular necrosis of the body |
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of the talus occurs in displaced fractures of the talar |
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neck. The incidence varies with the severity of dis- |
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placement: in type I fractures it is less than 10%; in |
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type II about 30–40%; and in type III more than |
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90%. The earliest X-ray sign (often present by the |
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sixth week) is apparent increased density of the avas- |
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cular segment; in reality it is the rest of the tarsus that |
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has become slightly porotic with disuse, but the avas- |
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cular portion remains unaffected and therefore looks |
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more ‘dense’. The opposite is also true: if the dome of |
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the talus becomes osteoporotic, this means that it has |
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a blood supply and it will not develop osteonecrosis. |
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This is the basis of Hawkins’ sign, which should be |
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looked for 6–8 weeks after injury. |
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If osteonecrosis does occur, the body of the talus |
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will eventually appear on X-ray to be more dense than |
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the surrounding bones. Despite necrosis, the fracture |
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may heal, so treatment should not be interrupted |
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by this event; if anything, weight-bearing should be |
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delayed in the hope that the bone is not unduly flat- |
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tened. Function may yet be reasonable. However, if |
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the talus becomes flattened or fragmented, or pain |
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and disability are marked, the ankle may need to be |
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arthrodesed. |
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Secondary osteoarthritis Osteoarthritis of the |
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ankle and/or subtalar joints occurs some years after |
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injury in over 50% of patients with talar neck fractures. |
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There are a number of causes: (1) articular damage |
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due to the initial trauma; (2) malunion and distortion |
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of the articular surface; (3) avascular necrosis of the |
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talus. Pain and stiffness may be managed by judicious |
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analgesic medication and orthotic adjustments, but in |
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some cases the painful hindfoot will simply not allow |
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a return to function; arthrodesis of the affected joints |
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can help to relieve symptoms. Operative fusion of one |
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joint may predispose to overload of the associated foot |
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joints, and hence to later arthritis, but this should be |
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accepted, and is usually many years later. |
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FRACTURES OF THE CALCANEUM |
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The calcaneum is the most commonly fractured tarsal |
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bone, and in 5–10% of cases both heels are injured |
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simultaneously. Crush injuries, although they always |
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heal in the biological sense, are likely to be followed |
by long-term disability. The general attitude to these injuries at the beginning of the twentieth century (at least from an industrial point of view) was that ‘the man who breaks his heel-bone is finished’. This was followed by attempts, throughout the latter part of that century, to modify the outcome through open reduction and internal fixation of these fractures. The efficacy of fixation and the results of operative intervention have been studied and questioned in the past few years. There is still a role for fixation, but the decision-making and operative techniques require considerable expertise.
Mechanism of injury
In most cases the patient falls from a height, often from a ladder, onto one or both heels. The calcaneum is driven up against the talus and is split or crushed. Over 20% of these patients suffer associated injuries of the spine, pelvis or hip.
Avulsion fractures sometimes follow traction injuries of the tendo Achillis or the ankle ligaments. Occasionally the bone is shattered by a direct blow.
Pathological anatomy
Based largely on the work of Palmer and EssexLopresti in the 1940s and 1950s, it has been customary to divide calcaneal fractures into extra-articular fractures (those involving the various calcaneal processes or the body posterior to the talocalcaneal joint – Figure 32.20) and intra-articular fractures
(those that split the talocalcaneal articular facet).
EXTRA-ARTICULAR FRACTURES
These account for 25% of calcaneal injuries. They usually follow fairly simple patterns, with shearing or avulsion of the anterior process, the sustentaculum tali, the tuberosity or the inferomedial process. Fractures of the posterior (extra-articular) part of
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Figure 32.20 Extra-articular fractures of the calcaneum Fractures may occur through: 1 the anterior process,
2 the body, 3 the tuberosity, 4 the sustentaculum tali, or 5 the medial tubercle. Treatment is closed unless the fragment is large and badly displaced, in which case it will need to be fixed back in position.
the body are caused by compression. Extra-articular fractures are usually easy to manage and have a good prognosis.
INTRA-ARTICULAR FRACTURES
These injuries are much more complex and unpredictable in their outcome. They are best understood by imagining the impact of the talus cleaving the bone from above to produce a primary fracture line that runs obliquely across the posterior articular facet and the body from posteromedial to anterolateral (Figure 32.21). Where it splits, the posterior articular facet depends upon the position of the foot at impact: if the heel is in valgus (abducted), the fracture is in the lateral part of the facet; if the heel is in varus (adducted), the fracture is more medial.
The upward displacement of the body of the calcaneum produces one of the classic X-ray signs of a ‘depressed’ fracture: flattening of the angle subtended
by the posterior articular surface and the upper surface of the body posterior to the joint (Böhler’s angle).
The advent of CT, and the trend towards operative reduction and fixation of displaced calcaneal fractures, have sharpened our understanding of these complex injuries (Figure 32.22). There are two important ways of assessing or classifying these injuries that are of relevance to the treating surgeon (and the patient). The work of Sanders and Gregory has helped to define the intra-articular fracture pattern and the associated outcome and prognosis. Knowledge of the variations in fracture pattern, particularly in relation to the lateral wall of the calcaneum, has improved our understanding of the anatomy that is likely to be encountered at operation, approaching from an extended L-shaped incision; the lateral joint fragment may sometimes be trapped within the body of the calcaneum and can only be reduced if the lateral wall of the body is osteotomized so as to gain access to it.
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Figure 32.21 Intra-articular fractures of the calcaneum 1 The primary fracture line (a,b) is created by the impact of the talus on the calcaneum – it runs from posteromedial to anterolateral. Secondary fracture lines may create ‘tongue’ (c) or ‘joint depression’ (d) variants to the fracture pattern.
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S |
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Figure 32.22 Intra-articular fractures of the calcaneum 2 CT scans have allowed a better understanding of the fracture anatomy. A coronal CT scan enables the identification of three major fragments in most intra-articular fractures: the lateral joint fragment (L), the sustentaculum tali (S) and the body fragment (B). In type 1 fractures (a) the lateral joint fragment is in valgus whereas the body is in varus. In type 2 fractures (b), the sustentaculum tali is in varus and the lateral joint is elevated in relation to it. In type 3 fractures (c) the lateral joint fragment is impacted and buried within the body fragment.
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3
TRAUMA
Clinical features
There is usually a history of a fall from a height or a road traffic accident; in elderly osteoporotic people even a comparatively minor injury may fracture the calcaneum.
The foot is painful and swollen and a large bruise appears on the lateral aspect of the heel. The heel may look broad and squat. The surrounding tissues are thick and tender, and the normal concavity below the lateral malleolus is lacking. The subtalar joint cannot be moved but ankle movement is possible.
Always check for signs of a compartment syndrome of the foot (intense pain, very extensive bruising and swelling, diminished sensation, with pain on passive toe movement).
Imaging
Plain X-rays should include lateral views, but once a fracture has been identified then cross-sectional imaging (CT scan) is the standard of care. Extra-articular fractures are usually fairly obvious. Intra-articular fractures can also often be identified in the plain films and, if there is displacement of the fragments, the lateral view may show flattening of the tuber-joint angle (Böhler’s angle) (Figure 32.23).
For accurate definition of intra-articular fractures, however, CT is essential and 3D reconstruction views are even better. Coronal sections will show the fracture ‘geometry’ clearly enough to permit accurate diagnosis of most intra-articular fractures.
With severe injuries – and especially with bilateral fractures (Figure 32.24) or in the unconscious patient – it is essential to assess the knees, spine and pelvis as well.
Treatment
For all except the most minor injuries, the patient is admitted to hospital so that the leg and foot can be elevated and treated with cold (ice or Cryo-Cuff) and compression until swelling subsides. This also gives time to obtain the necessary CT scans.
EXTRA-ARTICULAR FRACTURES
The essence of management of extra-articular fractures is ‘mobility and function are more important than anatomical repositioning’. The vast majority are treated closed: (1) compression bandaging, ice packs and elevation until the swelling subsides; (2) exercises as soon as pain permits; (3) no weight-bearing for 4 weeks and partial weight-bearing for another 4 weeks. Variations from this routine relate to specific injuries.
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Figure 32.23 Fracture of the calcaneum – imaging (a,b) Measurement of Böhler’s angle and the X-ray appearance in a normal foot. (c) Flattening of Böhler’s angle in a fractured calcaneum. (d) The CT scan in this case shows how the articular fragments have been split apart.
Figure 32.24 Calcaneal fractures – imaging Bilateral calcaneal fractures (a,b) are caused by a fall on the heels from a height or by an explosion from below. In either case the spine also may be fractured, as it was in this patient (c). With bilateral heel fractures, always assess the spine.
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Figure 32.25 Extra-articular calcaneal fractures – treatment (a) Avulsion fracture of posterosuperior corner (b) fixed by a screw.
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Fractures of the anterior process Most of these are avulsion fractures and many are mistaken for an ankle sprain. Oblique X-rays will show the fracture, which almost always involves the calcaneocuboid joint. If there is a large displaced fragment, internal fixation may be needed; this is followed by the usual ‘closed’ routine.
Fractures of the tuberosity These are usually due to avulsion by the tendo Achillis; clinical signs are similar to those of a torn Achilles tendon. If the fragment is displaced, it should be reduced and fixed with cancellous screws (Figure 32.25); the foot is then immobilized in slight equinus to relieve tension on the tendo Achillis. Weight-bearing can be permitted after 4 weeks.
Fractures of the body If it is certain that the subtalar joint is not involved, the prognosis is good and the fracture can be treated by the usual ‘closed’ routine. However, if there is much sideways displacement and widening of the heel, closed reduction by manual compression should be attempted. Weight-bearing is avoided for 6–8 weeks; however, cast immobilization is unnecessary except if both heels are fractured or if the patient simply cannot or will not manage a onelegged gait with crutches (e.g. those who are elderly, frail or poorly compliant).
INTRA-ARTICULAR FRACTURES
Undisplaced fractures These are treated in much the same way as extra-articular fractures: compression bandaging, ice-packs and elevation followed by exercises and non-weight-bearing for 6–8 weeks. As long as vertical stress is avoided, the fracture will not become displaced; cast immobilization is therefore unnecessary and it may even be harmful in that it increases the risk of stiffness and algodystrophy. Good or excellent results can be expected in most patients with undisplaced intra-articular fractures.
Displaced intra-articular fractures Open reduction and internal fixation as soon as the swelling subsides is the best treatment for these fractures. CT has greatly facilitated this approach; the medial and lateral fragments can be clearly defined and, with suitable drawings or models, the surgical procedure can be carefully planned and rehearsed.
The operation is usually performed through a single, wide lateral approach; access to the posterior facet and medial fragment is achieved by taking down the lateral aspect of the calcaneum, performing the reduction, and then rebuilding this wall. The various fragments are held with interfragmentary screws – bone grafts are sometimes added to fill in defects. The anterior part of the calcaneum and the calcaneocuboid joint also need attention; the fragments are similarly reduced and fixed. Finally a contoured plate is placed on the lateral aspect of the calcaneum to buttress the entire assembly (Figure 32.26). The wound is then closed and may be drained.
Postoperatively the foot is lightly splinted and elevated. Exercises are begun as soon as pain subsides and after about 2 weeks the patient can be allowed
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Figure 32.26 Intra-articular calcaneal fracture – treatment (a) X-ray gives limited information, but the CT (b) shows the severe depression of the posterior calcaneal facet. This was treated operatively with a calcaneal locking plate, to reconstitute the posterior facet (arrow) and restore the height of the calcaneum (c,d).
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3up non-weight-bearing on crutches. Partial weightbearing is permitted only when the fracture has healed (seldom before 8 weeks) and full weight-bearing about 4 weeks after that. Restoration of function may take 6–12 months.
Outcome
TRAUMA |
Extra-articular fractures |
and undisplaced |
intra- |
articular fractures, if properly treated, usually have a |
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good result. However, the patient should be warned |
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that it may take 6–12 months before full function |
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is regained, and in about 10% of cases there will be |
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residual symptoms that might preclude a return to |
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their previous job if this involved walking on uneven |
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surfaces or balancing on ladders. |
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The outcome for displaced intra-articular frac- |
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tures is much less predictable. The results of opera- |
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tive treatment are heavily dependent on the severity |
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of the fracture and the experience of the surgeon. |
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A Canadian multicentre study showed a shorter time |
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off work and lower requirement for subtalar arthrod- |
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esis in those managed operatively. Results were par- |
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ticularly favourable with internal fixation in younger |
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men and those not working with heavy loads or |
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receiving workmen’s compensation. In experienced |
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hands, for selected fractures, this is a rational treat- |
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ment. A large multicentre UK trial cast doubt on the |
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need for fixation, but scrutiny of this revealed sig- |
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nificant selection bias. However, calcaneal surgery is |
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not an enterprise for the occasional foot and ankle/ |
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trauma surgeon and, unless the appropriate skills and |
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facilities are available, the patient should be referred |
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to a specialist centre. |
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The fact remains that the heel fracture is a serious |
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and disabling injury in many patients with heavy or |
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physically demanding jobs; mechanical reconstruction |
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of the bony anatomy does not necessarily improve the |
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functional outcome. |
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Complications |
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EARLY |
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Swelling and blistering |
Intense swelling and blis- |
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tering may jeopardize operative treatment. The limb |
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should be elevated with the minimum of delay. |
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Compartment syndrome |
About 10% of |
patients |
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develop intense pressure symptoms. The risk of a full- |
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blown compartment syndrome can be minimized by |
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starting treatment early. If operative decompression |
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is carried out, this will delay any definitive procedure |
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for the fracture. |
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LATE |
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Malunion Closed treatment of displaced fractures, |
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or injudicious weight-bearing after open reduction, |
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may result in malunion. The heel is broad and squat, and the patient has a problem fitting shoes. Usually the foot is in valgus and walking may be impaired.
Peroneal tendon impingement Lateral displacement of the body of the calcaneum may cause painful compression of the peroneal tendons against the lateral malleolus. Treatment consists of operative paring down of protuberant bone on the lateral wall of the calcaneum.
Insufficiency of the tendo Achillis The loss of heel height may result in diminished tendo Achillis action. If this interferes markedly with walking, subtalar arthrodesis with insertion of a bone block may alleviate the problem.
Talocalcaneal stiffness and osteoarthritis Displaced intra-articular fractures may lead to joint stiffness and, eventually, osteoarthritis. This can usually be managed conservatively but persistent or severe pain may necessitate subtalar arthrodesis. If the calcaneocuboid joint is also involved, a triple arthrodesis is better.
MIDTARSAL INJURIES
Injuries in this area vary from minor sprains, often incorrectly labelled as ‘ankle’ sprains, to severe fracture-dislocations that can threaten the survival of the foot. The mechanism differs accordingly, from benign twisting injuries to crushing forces that produce severe soft-tissue damage; bleeding into the fascial compartments of the foot may cause a typical compartment syndrome.
Isolated injuries of the navicular, cuneiform or cuboid bones are rare. Fractures in this region should be assumed to be ‘combination’ fractures or fracture-subluxations, until proved otherwise.
Remember that small flakes of bone on X-ray often have large ligaments attached to them, and that ‘midfoot sprain’ (like ‘partial Achilles tendon rupture’) is a dangerous diagnosis to make.
Pathological anatomy
The most useful classification is that of Main and Jowett, which is based on the mechanism of injury.
•Medial stress injuries are caused by violent inversion of the foot and vary in severity from sprains of the midtarsal joint to subluxation or fracture-subluxation of the talonavicular or midtarsal joints.
•Longitudinal stress injuries are the most common. They are caused by a severe longitudinal force with the foot in plantarflexion. The navicular is compressed between the cuneiforms and the talus,
resulting in fracture of the navicular and subluxation of the midtarsal joint.
•Lateral stress injuries are usually due to falls in which the foot is forced into valgus. Injuries include fractures and fracture-subluxations of the cuboid and the anterior end of the calcaneum as well as avulsion injuries on the medial side of the foot.
•Plantar stress injuries result from falls in which the foot is twisted and trapped under the body; they usually present as dorsal avulsion injuries or fracture-subluxation of the calcaneocuboid joint.
•Crush injuries usually cause open comminuted fractures of the midtarsal region.
Clinical features
The foot is bruised and swollen. Tenderness is usually diffuse across the midfoot. A medial midtarsal dislocation looks like an ‘acute club foot’ and a lateral dislocation produces a valgus deformity; with longitudinal stress injuries there is often no obvious deformity. Any attempt at movement is painful. It is important to exclude distal ischaemia or a compartment syndrome.
Imaging
Multiple X-ray views are necessary to determine the extent of the injury; be sure that all the tarsal bones are clearly shown. Tarsometatarsal dislocation may be missed if the forefoot falls back into place; fractures of the tarsal bones or bases of the metatarsals should alert the surgeon to this possibility (Figure 32.27). Abnormality of alignment, or fracture, on any view should lead to CT scanning to better assess the extent of injury (Figure 32.28).
Treatment
Ligamentous strains The foot may be bandaged until acute pain subsides. Thereafter, movement is encouraged. Be prepared to re-examine and re-X-ray the foot that does not settle within a few weeks.
Undisplaced fractures The foot is elevated to counteract swelling. After 3–4 days a below-knee cast or removable splintage boot is applied and the patient is allowed up on crutches with limited weight-bearing. The plaster is retained for 4–6 weeks.
Displaced fractures An isolated navicular or cuboid fracture is sometimes displaced and, if so, may need open reduction and screw fixation.
Fracture-dislocation These are severe injuries. Under general anaesthesia, the dislocation can usually be reduced by closed manipulation but holding it is a problem. If there is the least tendency to redisplacement, percutaneous K-wires are run across the joints to fix them in position.
The foot is immobilized in a below-knee cast for 6–8 weeks. Exercises are then begun and should be practised assiduously; it may be 6–8 months before function is regained.
If accurate reduction cannot be achieved by closed manipulation, open reduction and screw fixation is necessary; the importance of anatomical reduction cannot be overemphasized. However, missed fractures are a lost cause and open reduction will seldom improve the situation in those who present late (more than a few weeks after injury). In these cases an arthrodesis of the involved joints might be appropriate.
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Figure 32.27 Midtarsal injuries (a) X-ray showing dislocation of the talonaviclar joint. (b) X-ray on another patient showing longitudinal compression fracture of the navicular bone and subluxation of the head of the talus. This injury is often difficult to demonstrate accurately on plain X-ray.
Figure 32.28 Midtarsal injuries Reconstructed CT after |
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reduction of a severe tarsometatarsal injury reveals asso- |
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ciated injuries of the cuboid and the lateral cuneiform. |
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Comminuted fractures Severely comminuted frac- |
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tures defy accurate reduction. Attention should be |
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paid to the soft tissues; there is a risk of ischaemia. The |
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foot is splinted in the best possible position and ele- |
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vated until swelling subsides. Early arthrodesis, with |
TRAUMA |
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restoration of the longitudinal arch, is advisable, with |
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stable fixation and interpositional bone graft block. |
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Outcome |
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A major problem with midtarsal injuries is the fre- |
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quency with which fractures and dislocations are |
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missed at the first examination, resulting in under- |
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treatment and a poor outcome. Even with accu- |
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rate reduction of midtarsal fracture-dislocations, |
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post-traumatic osteoarthritis may develop and about |
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50% of patients fail to regain normal function. If |
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symptoms are persistent and intrusive, arthrodesis |
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may be indicated. |
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TARSOMETATARSAL INJURIES |
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The five tarsometatarsal (TMT) joints form a struc- |
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tural complex that is held intact partly by the interdig- |
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itating joints and partly by the strong ligaments that |
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bind the metatarsal bones to each other and to the |
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tarsal bones of the midfoot. |
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An appreciation of the anatomy across the TMT |
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joints is important in understanding these inju- |
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ries. The second metatarsal base is set into a recess |
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formed by the medial, intermediate and lateral |
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cuneiforms. There is no ligament between the first |
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and second metatarsal bases, but the plantar liga- |
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ment between second metatarsal base and medial |
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cuneiform is short and thick. In the coronal plane, |
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the second metatarsal base forms the apex or key- |
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stone in the arch. |
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Dislocation is rare, but important not to miss; |
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twisting and crushing injuries are the usual causes, |
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with the foot buckling or twisting at the midfoot– |
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forefoot junction. The term Lisfranc injury is often |
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used for the disruptions that occur at the midfoot– |
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forefoot junction. Classifying these by direction |
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of forefoot dislocation is, however, pointless – it is |
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neither a guide to treatment nor an indication of |
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outcome. These are often high-energy injuries with |
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extensive damage to the whole region of the foot, |
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and simply to assess the direction of metatarsal dis- |
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placement is to miss the complexity of the injury |
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falls. Unfortunately, about 20–30% of these injuries are initially missed. Only with severe injury is there an obvious deformity.
Imaging
X-rays may be difficult to interpret; something looks wrong but it is often difficult to tell what. A systematic method for examining the foot X-rays can help to improve the pick-up rate for these injuries. Concentrate on the second and fourth metatarsals in the oblique views: the medial edge of the second should be in line with the medial edge of the second cuneiform, and the medial edge of the fourth should line up with the medial side of the cuboid. A true lateral may show the dorsal displacement of the second metatarsal base. If a fracture-dislocation is suspected (the displacement may reduce spontaneously and not be immediately detectable), stress views may reveal the abnormality, but a CT scan is a more efficient way of showing the extent of injury.
Treatment
The method of treatment depends on the severity of the injury. Undisplaced sprains require cast or boot immobilization for 4–6 weeks. Subluxation or dislocation calls for accurate reduction. This can often be achieved by traction and manipulation under anaesthesia; the position is then held with percutaneous K-wires or screws and cast immobilization (Figure 32.29). The cast is changed after a few days when swelling has subsided; the new cast is retained, non-weight-bearing, for 6–8 weeks. The K-wires are then removed and rehabilitation exercises begun.
If closed reduction fails, open reduction is essential. The key to success is the second TMT joint. Through a longitudinal incision, the base of the second metatarsal is exposed and the joint manipulated into position. Reduction of the remaining parts of the tarsometatarsal articulation will not be too difficult. The bones are fixed with percutaneous K-wires or screws and the foot is immobilized as described earlier.
Complications
Compartment syndrome A tensely swollen foot may hide a serious compartment syndrome that could result in ischaemic contractures. If this is suspected, intracompartmental pressures should be measured (see Chapter 23). Treatment should be prompt and effective in decompressing the affected area. Through a medial longitudinal incision, or two well-spaced dorsal incisions, all the compartments can be decompressed; the wound is left open until swelling subsides and the skin can be closed without tension or grafted with a meshed graft that will later contract.
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Figure 32.29 TMT injuries (a) Dislocation of the TMT joints. (b) X-ray after reduction and temporary stabilization with K-wires – later stabilization with screw fixation was performed. (c) X-ray showing a high-energy fracture-dislocation involving the TMT joints. These are serious injuries that may be complicated by (d) compartment syndrome of the foot.
INJURIES OF METATARSAL BONES
Metatarsal fractures are relatively common and are of four types: (1) crush fractures due to a direct blow;
(2) a spiral fracture of the shaft due to a twisting injury; (3) avulsion fractures due to ligament strains;
(4) insufficiency fractures due to repetitive stress.
Clinical features
In acute injuries pain, swelling and bruising of the foot are usually quite marked; with stress fractures, the symptoms and signs are more insidious.
X-rays
X-rays should include routine AP, lateral and oblique views of the entire foot; multiple injuries are not uncommon. Undisplaced fractures may be difficult to detect and stress fractures usually show nothing at all until several weeks later.
Treatment
Treatment will depend on the type of fracture, the site of injury and the degree of displacement.
UNDISPLACED AND MINIMALLY DISPLACED FRACTURES
These can be treated by support in a below-knee cast or removable boot splint; the foot is elevated and active movements are started immediately, partial weight-bearing for about 4–6 weeks. At the end of that period, exercise is very important and the patient is encouraged to resume normal activity. Slight malunion rarely results in disability once mobility has been regained.
DISPLACED FRACTURES
Displaced fractures can usually be treated closed. The foot is elevated until swelling subsides. The fracture may be reduced by traction under anaesthesia and the leg immobilized in a cast – non-weight-bearing – for 4 weeks. Alternatively the fracture position might be accepted, depending on the degree of displacement. For the second to fifth metatarsals, displacement in the coronal plane can be accepted and closed treatment, as above, is satisfactory. However, for the first metatarsal and for all fractures with significant displacement in the sagittal plane (i.e. depression or elevation of the displaced fragment) open reduction and internal fixation with K-wires, or better with stable fixation using a plate and small screws, is advisable. A below-knee cast or boot is applied and weightbearing is avoided for 4 weeks; this is then replaced by a weight-bearing cast or boot for another 4 weeks.
Fractures of the metatarsal neck have a tendency to displace, or re-displace, with closed immobilization. It is therefore important to check the position repeatedly if closed treatment is used. If the fracture is unstable, it may be possible to maintain the position by percutaneous K-wire or screw fixation. The wire is removed after 4 weeks; cast immobilization is retained for 4–6 weeks.
FRACTURES OF THE FIFTH
METATARSAL BASE
Forced inversion of the foot (the ‘pothole injury’) may cause avulsion of the base of the fifth metatarsal, with pull-off by the peroneus brevis tendon or the lateral band of the plantar fascia (Figure 32.30). Pain due to a sprained ankle may overshadow pain in the foot. Examination will disclose a point of tenderness
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foot and ankle the of Injuries
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TRAUMA
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Figure 32.30 Metatarsal injuries (a) Transverse fractures of three metatarsal shafts. (b) Avulsion fracture of the base of the fifth metatarsal – the pothole injury, or Robert Jones fracture. (c) Florid callus in a stress fracture of the second metatarsal. (d) Jones fracture of the fifth metatarsal.
directly over the prominence at the base of the fifth metatarsal bone.
A careful assessment of the fracture pattern will provide a guide to prognosis and treatment. Again, an appreciation of the pathoanatomy explains these factors.
The fifth metatarsal base extends much more proximal into the midfoot region, compared to the other metatarsal bases. It articulates with the cuboid and with the fourth metatarsal. The peroneus brevis tendon and lateral band of the plantar fascia insert onto the base of the fifth metatarsal. There is a relative watershed in the blood supply to the fifth metatarsal at the junction between the diaphysis and metaphysis.
Robert Jones, a founding father and doyen of orthopaedics, described his own fracture (sustained while dancing), as a fracture of the fifth metatarsal about three-fourths of an inch from its base. Unfortunately, as observed above with Pott’s fractures, what has passed into history as this eponymous fracture is often not what was actually described, and the term ‘Jones fracture’ is now sometimes used for any fracture of the proximal fifth metatarsal. A more useful classification system takes account of the fracture line, and whether it is proximal, affecting the tuberosity, in the region of articulation with the fourth metatarsal, or at the metaphyseal/diaphyseal junction – the latter has a higher rate of non-union, probably as a consequence of the relatively poor blood supply in that region.
Occasionally a normal peroneal ossicle in this area may be mistaken for a fracture; there is also an apophyseal ossification centre in the tuberosity.
interfragmentary screw or screws and plate is therefore an issue for discussion between the surgeon and the patient, depending to a large extent on the patient’s functional demands and expectations with respect to sport and activity, and time away from these.
STRESS INJURY (MARCH FRACTURE)
In a young adult (often a military recruit or a runner building up training) the foot may become painful and slightly swollen after overuse. A tender lump is palpable just distal to the midshaft of a metatarsal bone. Usually the second metatarsal is affected, especially if it is much longer than an ‘atavistic’ first metatarsal. The X-ray appearance may at first be normal but a radioisotope scan will show an area of intense activity in the bone. Later a hairline crack may be visible and later still (4–6 weeks) a mass of callus is seen.
Unaccountable pain in elderly osteoporotic people may be due to the same lesion; X-ray diagnosis is more difficult because callus is minimal and there may be no more than a fine linear periosteal reaction along the metatarsal. If osteoporosis has not already been diagnosed, then this should be considered and assessed with bone densitometry.
Metatarsal pain after forefoot surgery may also be due to stress fractures of the adjacent metatarsals, a consequence of redistributed stresses in the foot.
No displacement occurs and neither reduction nor splintage is necessary. The forefoot may be supported with an elastic bandage and normal walking is encouraged.
Treatment
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The proximal avulsion fractures can usually be treated |
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with early mobilization and return to function. |
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The intra-articular injuries and those at the metaph- |
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yseal–diaphyseal junction may also be treated non- |
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operatively, but there is a greater risk of non-union and |
slower return to function. The role of fixation with an |
INJURIES OF
METATARSOPHALANGEAL JOINTS
Sprains and dislocations of the metatarsophalangeal (MTP) joints are common in dancers and athletes. A simple sprain requires no more than light splinting; strapping a lesser toe (second to fifth) to its neighbour