Dancers ankle injury

Nick Cullen takes a tour of the damage wreaked by this most graceful artform

Dancers put high stresses through their feet and ankles, often at the extremes of the range of movement of certain joints. Among female dancers in particular, the vulnerability of the foot and ankle is frequently compounded by the risk of injury as a result of the ‘female triad’ (nutritional deficiencies, amenorrhea and osteopenia). Up to 40% of all dance injuries occur to the foot and ankle.

Injuries may be acutely traumatic or chronic overuse. Chronic injuries may result from repetitive fatigue or impingement syndromes. Early recognition of symptoms and prompt treatment will help to speed the dancer’s return to performance, and can be career-saving.

Acute trauma

High level dance generates large forces within the skeleton, usually the result of the body’s deceleration from jumps and twists; ballet also requires remarkably fine-tuned balance. It is the combination of loss of balance and large force that causes many acute injuries among dancers.

Ankle sprains

Ankle sprains are common. They result from dancers working for hours a day in positions that predispose to sprains. The most common cause is loss of balance when landing from a jump. The anatomical location of injury depends on the ankle position during impact.

The talus is wider at the front and narrower at the back, making the joint potentially unstable in plantar flexion. However dancers rarely sprain the ankle when in full plantar flexion, such as at full pointe, as the ankle is stable, with the hindfoot locked into varus and the calcaneus engaged at the rear (posteriorly).

In full pointeit is the midfoot that is most frequently injured, however when the hindfoot unlocks, with just a few degrees of dorsiflexion off full pointe, the ankle becomes incongruent again, predisposing it to liga- mentous injury. In dorsiflexion the ankle again becomes stable. The most frequently injured ligament is the anterior talofibular ligament (ATFL), followed by the calcaneofibular (CFL, see Fig 1). Sprains are graded 1-3 in increasing severity.

Grade 1 sprains are the most common, representing partial tears of the lateral ligament, with lateral (outer edge) pain and swelling. Weight bearing is comfortable and tests (inversion and anterior drawer) will show no increased laxity. These injuries do not need immobilisation, but a RICE (rest, ice, compression, elevation) regime and early rehabilitation with peroneal and proprioceptive exercises. The client can expect to return to dance within three to four weeks.

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Grade 2 injuries involve a tear of the ATFL, with lateral swelling, a positive anterior drawer and negative inversion test. Weight bearing is uncomfortable. These ankles need to be immobilised for three weeks, followed by rehabilitation. The dancer should expect to take up to eight weeks before they return to dance.

Grade 3 injuries involve rupture of the entire lateral ligamentous complex and in essence are a kind of ankle dislocation; fortunately this is an uncommon pattern of sprain in dance. The dancer will have marked swelling and find weight bearing difficult because of pain; anterior draw and inversion tests will show gross instability. The optimal management of grade 3 injuries is contro- versial: some propose surgical repair, others immobilisation in a pneumatic walker (lightweight immobilising boot), allowing sagittal plane movement only, for four to six weeks, followed by peroneal strengthening and proprioceptive rehabilitation. A return to dance may take 12 weeks.

Grade 2 and 3 sprains can mimic fractures, so x-ray is advisable when a dancer is unable to weight-bear or has tenderness over the malleoli.

Chronic sprains

Pain, swelling or instability may persist after a sprain, which can be a result of:

Chronic ankle instability

This may be rotational or varus (inward- tilting). Varus instability is often compensated for by proper peroneal training. Rotational instability is very difficult to correct with rehabilitation. Dancers notice rotational instability when performing ‘inside turns’ (when the upper body is rotated outwards with the feet fixed to the floor).

Persistent pain

Anterolateral impingement can be caused by an incarcerated lateral ligament, synovitis or meniscoid type lesions. It often requires arthroscopic cleaning out. Pain may be exacerbated by peroneal weakness, so an appropriate peroneal rehabilitation programme is essential.

Longitudinal tears of the peroneal tendon, or peroneal subluxation, are often linked to persistent outer-edge ankle pain, swelling and clicking. Ultrasound or MRI scan are very good at showing subluxation and tears; these generally need surgical repair.

Osteochondral defects of the talar dome occur during ankle sprains and fractures. They can present with persisting pain, intermittent swelling, clicking and locking. Osteochondral lesions are best diagnosed on MRI scan and are treated initially with arthroscopic cleaning out and drilling. Resistant lesions are treated with chondral or osteochondral transplant.

Hindfoot injuries

Hindfoot sprains and dislocations are often misdiagnosed as ankle sprains. They involve injuries to the interosseous and cervical ligaments, or dislocations of the subtalar or calcaneocuboid joints. Hindfoot dislocations frequently produce stiffness or ongoing instability. These injuries may present with persistent instability or pain and swelling in the sinus tarsi (‘sinus tarsi syndrome’).

Midfoot injuries

These occur as a result of loss of balance in the en pointeposition. They present with midfoot swelling and tenderness. Chronic midfoot injuries also occur, associated with ‘sickling’ (excessive supination). Weight bearing x-rays of the foot may show diastasis (separation) of the Lisfranc joint; stress x-rays or CT scan should also be considered as the deformity may be subtle. Undisplaced injuries or those with mild laxity may be immobilised in a plaster cast, displaced injuries are treated operatively to close and fix the gap.

Fractures

Ankle

Ankle fractures are uncommon in dancers. Stable fractures may be treated in a plaster cast; displaced or unstable fractures are treated surgically to prevent problems with bone healing and allow early rehabilitation.

Fifth metatarsal base

Dancers are susceptible to fractures of the fifth metatarsal (see Fig 3, opposite). These may be avulsion type fractures of the base or occur at the metaphyseal-diaphyseal junction. Suspected fifth metatarsal fractures should be investigated with plain x-ray. Many are treated symptomatically in a pneumatic walking boot, but displaced intra-articular fractures and those at the metaphyseal- diaphyseal junction should be surgically fixed.

Chronic overuse injuries

Stress fracture

Stress fractures are caused by repeated loading of a bone. Dancers have a high incidence of osteopenia in which their bones are weaker and more prone to a type of stress fracture known as insufficiency fracture.

Stress fractures can occur in any bone in the lower limb. They initially present as pain after activity, but with time pain can be experienced during normal activity and at rest, and night pain is quite common. The patient may find it hard to pinpoint the source of pain and frequently there is a paucity of clinical findings – x-rays, for instance, can show as normal, especially within two weeks of onset. It is therefore important to keep this injury in mind, as early diagnosis will minimise recovery time for the dancer.

The most common stress fracture among dancers is to the base of the second metatarsal. The area will be tender to palpa- tion. MRI or bone scan should be performed in those with negative or equivocal radiographs. Most of these fractures heal with conservative treatment, which should involve immediate rest and immobilising the foot in a pneumatic walker, returning to dance once the patient is pain free.

Other stress fractures are managed similarly. However, navicular stress fractures (which are fortunately relatively uncommon), require more stringent immobilisation in a below-knee cast if the fracture extends into cortical bone.

Complete fractures and those remaining symptomatic after immobilisation should be surgically fixed.

Flexor hallucis longus (FHL) dysfunction

Among dancers the FHL tendon is particularly susceptible to injuries (see Fig 2, above). In some dancers, when the foot is in extreme ankle dorsiflexion, the muscle belly of the FHL will impact on the fibro-osseous canal of the tendon. Repeated impaction may cause medial (inner side) ankle pain.

Alternatively, the FHL tendon can become entrapped along its course, resulting in stenosing tenosynovitis and partial tears and nodules. The nodules can produce trig- gering of the great toe. FHL tendinosis is frequently found in association with posterior impingement syndromes.

In addition to its role as a flexor of the great toe (big toe), the FHL is a dynamic stabiliser of the medial foot and ankle, especially in plantar flexion. Repetitive activity such as en pointeor sickling in abduction may cause the tendon to become inflamed.

Initial treatment is RICE and rehabilitation, with a graduated return to activity, restricting pliéand pointework. Where conservative management fails, surgical decompression of the FHL sheath may be appropriate.

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Achilles tendinosis

Achilles tendinosis is common in dancers, with overuse being a significant factor. It is not usually an inflammatory condition other than in the early stages. The dancer places heavy demands on the tendon during en pointeand plié. Mechanical contributors are overpronation and tight heel cords.

Dancers usually present with local tenderness over the Achilles tendon, occasionally with swelling. Initial treatment is rest, ice and physiotherapy; a heel raise can be used but should be discarded as soon as possible to avoid further calf contracture. Rehabilitation should progress through concentric and eccentric strengthening and stretching exercises. Orthotic management for overpronation can be useful but often proves impractical in dance footwear. Steroid injections should be avoided: this is not an inflammatory condition and these injections can predispose to tendon rupture. Surgical cleaning out may be needed if conservative manage- ment fails.

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Sesamoid disorders

Large forces pass through the sesamoids during dance, notably when rolling through on demior full pointe, so dancers are prone to injuries including fracture arthritis and ‘sesamoiditis’.

Sesamoid injuries can result in prolonged disability. Dancers complain of pain in the plantar aspect of the ball of the foot. Pain is worse on passive dorsiflexion and resisted plantar flexion.

Treatment is symptomatic and can require extended periods away from dance. Work in demi pointeshould initially be restricted and an offloading U-shaped pad should be worn. Steroid injections can be useful. Sesamoidectomy can be considered in resistant cases but should be regarded as a last resort, as it may prevent a return to high level dance.

Impingement syndromes

The extremes of plantar and dorsiflexion that certain dance positions require can lead to impingement syndromes of the front and rear ankle joints.

In anterior impingement, the pain may at first be poorly localised, usually occurring during plié. It may present as a restriction to dorsiflexion and be mistakenly diagnosed as tight heel cords – the prescribed stretching regimes for such injuries may in this case exacerbate the problem.

Anterior spurs (osteophytes, bony prominences) may develop after prolonged impingement or can result from ankle sprains. Examination may reveal anterior ankle tenderness, especially in dorsiflexion. Lateral ankle x-rays in maximal dorsiflexion show tibiotalar contact.

The dancer should take anti-inflammatories, use a small heel raise when not dancing, and avoid provocative positions. Arthroscopic clear-out of osteophytes is performed if conservative treatment fails, but spurs do tend to recur over a few years.

In posterior impingement, also known as ‘talar compression syndrome’, the dancer will feel pain at the rear of the ankle, especially in the demiand en pointepositions. The pain can prevent the dancer from achieving these positions. There may be posterior swelling, tenderness and crepitus (grinding). Rapid dorsiflexion from a plantar flexed position reproduces the symptoms.

Posterior impingement may be soft tissue or bony. Bony impingement results from a prominent posterior process of talus, an accessory posterior ossicle ‘os trigonum’ (these can be associated with FHL tendinosis), or occasionally a prominent calca- neus. Ankle instability can also cause posterior impingement.

Treatment in the early stages involves restriction of relevéand en pointe,proprioceptive work and anti-inflammatory medica- tion. Ultrasound-guided injection may help settle symptoms. Surgical excision of the os trigonum or prominent posterior process may be appropriate.

Further reading

* Faciszewski, T, Burks, RT, Manaster, J (1990) ‘Subtle Injuries of the lisfranc joint’, JBJS. 72-A;10. 1519-22.

* Hamilton, WG (1982) ‘Stenosing tenosynovitis of the flexor hallucis longus tendon and posterior impingement upon the os trigonum in ballet dancers’. Foot & Ankle, 3:74-80.

* Hamilton, WG(1982) ‘Sprained ankles in ballet dancers’. Foot & Ankle. 3.2; 99-102

* Hamilton, WG, Geppert, MJ, Thompson, FM (1996) ‘Pain in the posterior aspect of the ankle in dancers: Differential diagnosis and operative treatment’. JBJS, 78-A; 10. 1491-99.

* Hardaker, WT, Margello, S, Goldner, JL (1985) ‘Foot and ankle injuries in theatrical dancers’. Foot & Ankle, 6; 2. 59-69.

* Kleiger, B (1982) ‘Anterior tibiotalar impingement syndromes in dancers’. Foot & Ankle, 3;2 69-73.

* Kolettis, GJ, Micheli, LJ, Klein, JD (1996) ‘Release of the flexor hallucis longus tendon in ballet dancers’. JBJS, 78-A; 9 1386-90.

* Macintyre, J, Joy, E (2000) ‘Foot and ankle injuries in dance’. Clinics in Sports Medicine, 19;2 351-66.

* Martin, J, O’Malley, WGH et al (1996) ‘Stress fractures at the base of the second metatarsal in ballet dancers’. Foot & Ankle International, 17:89-94.

* Ryan AJ, Stephens, RE (1987) ‘The epidemiology of dance injuries’, in Ryan AJ and Stephens RE (Eds), Dance medicine – A Comprehensive Guide, Chicago, Pluribus press.

* Wredmark, T, Carlstedt, CA et al (1991) ‘Os trigonum syndrome: A clinical entity in ballet dancers’. Foot & Ankle, 11.6; 404-06.