Normal apophysis (more parallel to the shaft) is shown along with an avulsion fracture, which is more transverse at the base of the fifth metatarsal in a skeletally immature foot. Apophysis plus fracture: case courtesy of Dr. Alexandra Stanislavsky
Whenever loading is increased too rapidly, or there is repeated microtrauma of physiological loads that exceed the bones reparative capacity, a stress fracture can occur. Increased training intensity, hard floors, nutritional and hormonal factors, menstrual irregularities, low body mass index, and low energy availability have all been implicated in stress fractures. Dancing more than 5 h per day and having amenorrhea greater than 90 days have been demonstrated as risk factors for stress fractures in female dancers . Metatarsal stress fractures are the most common stress fracture reported in dancers [30, 31]. The fibula, tibia, spine, and hip are other potential sites.
The dancer with a stress fracture will report a dull, achy pain in the injured area. Initially pain will typically occur near the end of class or with jumps. A marked increase in training intensity (such as a summer dance program) often precedes the symptoms. As symptoms progress pain becomes more constant, and may occur with walking and at night. Rarely is swelling present, and often pain is not well localized. Bony tenderness may be present. Initial radiographs are often normal. Radionuclide bone scans can be positive only a few days after the injury, but MRI is recommended to make the diagnosis (Fig. 9.2a, b).
a Anteroposterior radiograph of healing right fibula stress fracture in 14-year-old female elite ballet dancer who developed ankle pain week 5 of a 6-week summer dance intensive program. b Lateral radiograph of the same healing right fibula stress fracture. The dancer was able to walk without pain after a total of 3 weeks in a removable boot and was allowed to weight-bear in sneakers and start pool, Pilates, and elliptical trainer exercises. Graduated return to full dance activities was begun after additional 3 weeks when radiographs demonstrated further healing
Dancers are at risk for a stress fracture at the base of the second metatarsal. Running athletes typically will have a stress fracture of the midshaft or more distal aspect of the metatarsal [31, 32]. In the midfoot, the second metatarsal is recessed and the second metatarsal-cuneiform joint is more proximal than the first or third metatarsal-cuneiform joints. The first and second metatarsals bear the majority of a dancers’ weight whether on demi-pointe, pointe, or in landing from a jump, and those stresses are transmitted proximally to the midfoot, where the base of the second metatarsal is locked in .
Synovitis of Lisfranc’s joints (the metatarsal-cuneiform joints) and a proximal second metatarsal stress fracture are difficult to distinguish with physical exam or a bone scan [31, 32, 34–36]. Therefore, MRI has become the preferred test in a dancer with midfoot pain, a suspected stress fracture, and negative radiographs. Healing time is prolonged for the stress fracture (6–8 weeks) compared to synovitis (3 weeks); hence, accurate diagnosis is important for managing these injuries . Treatment for foot and ankle stress fractures does not usually require casting, but some dancers need a removable cast boot for pain-free walking outside of class. Bone stimulators are often used to aid healing. Attention to energy availability, calcium and vitamin D levels, and correction of any deficits is important. Conditioning can be maintained with floor barre, Pilates, pool exercises, and exercise bicycle or elliptical trainer barring pain at the fracture site with those activities. Rehabilitation includes gradual return to class with avoidance of painful activities such as pointe work, jumps, turns, and demi-pointe until healing is completed and pain resolved.
Midfoot sprains/fractures in young dancers are not common, but the physician treating dancers should have a high index of suspicion because if this injury is not recognized and treated it can be career ending. The ligaments of the tarso-metatarsal joints act to support the medial and longitudinal arches of the foot. These injuries can be easily missed as radiographic findings may be subtle, and the midfoot pain can be mistaken for possible stress fracture or synovitis. Usually, these injuries have more swelling when compared to a stress fracture or isolated synovitis. Tenderness over the dorsal midfoot (especially the first and second metatarsal-cuneiform joints) is present. In acute cases plantar midfoot ecchymosis may be seen, increasing the likelihood of a Lisfranc injury diagnosis. Weight bearing AP radiographs may show a small diastasis between the first and second metatarsal bases (comparison views of the opposite foot aid in making the diagnosis). Lisfranc’s ligament is located between the medial cuneiform and the base of the second metatarsal. An avulsed fragment of bone between the first and second metatarsal bases may be seen if the ligament is injured.
The mechanism of injury to Lisfranc’s joints in dancers has been described to include a fall off pointe position, missed jump landings, take-off for a jump, and a foot catching a seam or irregularity in the floor. These injuries occur in ankle plantar flexion, with or without rotation, often with the metatarsal-phalangeal joints in maximal dorsiflexion (demi-pointe) [29, 37–39]. Most Lisfranc injuries require surgical treatment, and only a simple sprain with no instability should be treated non-surgically. Any suspected Lisfranc injury should be referred to an orthopaedic surgeon for evaluation. Recovery is prolonged, and immobilization with avoidance of weight bearing activities for 6–12 weeks is required. Rehabilitation of the entire kinetic chain will be needed to return the dancer to full performance level.
The plantar aponeurosis is a strong band of fascia extending from the calcaneal tuberosity to attach at the plantar aspect of the proximal phalanges. In young dancers plantar fasciitis usually coincides with calcaneal apophysitis, but in older adolescent dancers with closed physes it can exist by itself and presents as plantar-medial arch or heel pain . The literature suggests that this is not a true inflammatory condition, but rather the result of repetitive microtrauma after increased training intensity . Dancers will usually have pain with their first few steps in the morning, which improves quickly and then worsens later with increased activity. Diagnosis is based on history and physical exam findings of tenderness over the anteromedial aspect of the heel, worst with the foot and toes in dorsiflexion and less tender with plantar flexion of the toes. This, like Sever’s disease, is a clinical diagnosis, because radiographs are often not helpful. However, tenderness of the calcaneal wall should alert the clinician to a possible calcaneal stress fracture (or Sever’s disease in a skeletally immature dancer), and further imaging is needed.
Treatment should include relative rest (including avoidance of painful activities), dorsiflexion night splint for sleeping, and gastrocnemius, soleus, and plantar arch stretches. Use of a stiff-soled shoe for walking, such as hiking boots or clogs, can help to avoid stressing the plantar fascia by limiting flexion of the MTP joints . Use of the night splint and stiff-soled shoes is often needed for 4–6 weeks minimum. Taping the foot arch can improve symptoms in many dancers.
Apophysitis of the Os Calcis (Sever’s Disease)
Sever’s disease (calcaneal apophysitis) is a traction apophysitis and should be considered in any young dancer with open physes (growth plates) who complains of heel pain. The calcaneal apophysis is located in the posterior calcaneus, oriented perpendicular to the long axis of the tuberosity. It first appears on radiographs at ages 4–7 years in females and 4–10 years in males; it does not fuse until an average age of 16 years. The Achilles tendon inserts along the posterior calcaneal tuberosity, and the plantar fascia on the plantar medial tuberosity [28, 29]. The diagnosis is particularly common in Irish step dancers, and seen in both males and females . The dancer may complain of heel pain in the morning, pain with jumping, on heel strike when walking, and with percussive movements. Radiographs are often negative, but fragmentation or widening of the growth plate may be present. Physical exam findings include tenderness to palpation over the apophyseal calcaneal growth plate and posterior heel, pain with medial and lateral squeeze test of the calcaneus, weakness of ankle dorsiflexion, and contracture of the Achilles tendon .
Treatment includes avoidance of painful activities, and in most cases use of a removable walking boot cast for three weeks, plantar fascia night splint for sleeping, and gentle Achilles stretches along with ankle dorsiflexion resistance band strengthening. The young dancer may need to continue use of the night splint for sleep and wearing a cushioned supportive shoe outside of class for an additional 4–6 weeks as symptoms subside. Return to dance includes relative rest, such as avoidance of jumps and other painful maneuvers, until symptoms are resolved.
Ankle sprain is the most frequent traumatic injury in dancers, and may be related to the increased time dancers spend weight bearing in ankle plantar flexion, a highly unstable position for the ankle joint. Rolling over the lateral border of the foot while on pointes or demi-pointe, or landing poorly from a jump, is the usual mechanism of injury. In most ankle sprains, the lateral ligaments are injured, especially the anterior talofibular ligament (ATFL). The ATFL is injured when the ankle is in plantarflexion; the calcaneofibular ligament (CFL) is injured when the inversion occurs with the ankle (foot) in dorsiflexion (or neutral) position. It is important to note that in younger dancers with open growth plates there is a higher risk of physeal injury or fracture rather than ligamentous disruption. Any tenderness of the distal fibula should be assessed for possible distal fibula fracture or physeal (growth plate) injury. It is well recognized that the greatest risk factor for an ankle sprain is a previous inversion injury, and those dancers with a cavus foot type and varus heel also have higher inversion injury risk [42–46].
Findings on examination include tenderness to palpation over the anterolateral ankle ligaments, swelling, and ecchymosis. Laxity on ankle drawer testing may be present, but must be compared to the contralateral ankle. Any tenderness over the fibula, sinus tarsi, or fifth metatarsal should alert the clinician to obtain foot and ankle radiographs. A computed tomography (CT) scan or magnetic resonance imaging (MRI) scan should be obtained to identify possible osteochondral injury to the talus or occult fracture if symptoms have not started to improve in one week. In cases of recurrent sprains, AP stress views of both ankles can help quantitate the degree of instability, with 5° difference between sides considered significant.
The majority of sprains resolve with conservative management. Early functional treatment of ankle sprains is recommended. Compression bandage, brief icing, ankle air-stirrup brace in athletic shoes outside of class, and limited class participation are instituted as pain allows. Severe sprains may require use of a removable walking boot cast for 3 weeks. The boot should be removed for icing and range-of-motion exercises, and worn for walking and sleeping until pain resolves (not more than 3 weeks). McCormack et al. observed that dancers with generalized hypermobility have a more prolonged recovery from soft tissue injuries than non-hypermobile dancers [47, 48].
Attention to strengthening, edema control, and range of motion and proprioception exercises are needed for rehabilitation from an ankle sprain. Ballet dancers require full mobility of their hindfoot, midfoot, and ankle joints to dance en pointe. Failure to restore posterior talar glide and full ankle dorsiflexion following ankle sprain may lead to posterior ankle impingement . The insufficient ATFL allows the talus to translate forward in the ankle mortise in the plantar flexed position, resulting in impingement of bone and/or soft tissues in the posterior ankle joint. It is important in dancers to encourage work on attaining full dorsiflexion at the tibiotalar joint following an ankle sprain; therapists should be encouraged to assist the dancer in achieving posterior talar glide and restoration of subtalar joint mobility with manual therapy.
Dancers often have a very flexible ankle and a moderately or highly arched (cavus) foot. Subtle hindfoot varus may be present, increasing the prospect of re-injury. Studies have found dancers and athletes with previous ankle sprain have impaired dynamic postural control (more postural sway than controls or uninjured dancers). Even after return to full professional dance or sport participation, and without complaints of instability, measurable differences in postural sway can be demonstrated [42–46].
Work on the entire kinetic chain is crucial for full recovery. Core strengthening, proprioception, and proximal hip strengthening exercises should be included in any dancer’s rehabilitation from ankle sprain, in addition to fibularis longus and brevis muscle strengthening. Work on unstable surfaces and balance tasks with eyes closed will assist return of proprioception and full function. Practicing relevés in parallel position with a tennis ball held between the malleoli can help the injured dancer retrain ankle strength and motion in a neutral ankle joint position, avoiding sickling during relevé .
Osteochondritis dessecans of the talus is an injury or abnormality of the articular cartilage and subchondral bone of the talar dome. In the ankle, an osteochondral lesion on the talus is an area of subchondral bone with poor blood supply and inflammation, osteonecrosis, and delamination, with an abnormality of the overlying articular cartilage. Theories regarding the cause include repeated microtrauma, multiple ankle sprains, and genetic factors. A history of trauma is implicated in 75–94% of patients, less often in posteromedial lesions. Lesions may be bilateral in up to 10% of cases. Exact incidence is unknown, but is estimated to occur in 40–70% of cases after ankle sprain. Age at presentation is most commonly the second decade, but ranges from age 10 to 40. Symptoms typically include deep ankle pain with weight bearing activities, stiffness, and limited range of motion. Catching, clicking, locking, and swelling may occur. MRI is the best study for suspected lesions, as they may be difficult to identify on radiographs. These dancers should be referred to an orthopaedic foot and ankle specialist for treatment. Initial treatment in adolescents involves casting in removable boot, crutches, and non-weight bearing in an attempt to heal the lesion if not displaced [50–52].
Ankle Impingement Syndromes
Posterior Ankle Impingement
The term “posterior ankle impingement” is used to describe any painful condition due to compression of soft tissues or bone between the posterior edge of the tibia and the calcaneus, typically when the ankle is in plantar flexion. A normal ossification center is located at the posterior aspect of the talus. It usually appears at 9–12 years of age and fuses 1 year after its appearance. If it does not fuse with the talus, an ossicle develops, known as the os trigonum . This ossicle or a large posterior lateral process of the talus called a Steida process are the usual sources of bony impingement (Fig. 9.3a, b). While it may be seen at any age, most commonly this problem presents in the adolescent dancer. Flexor hallucis longus (FHL) tenosynovitis secondary to an impinging os trigonum is also reported in dancers, and should be suspected in any dancer with posterior ankle pain [53–63]. An acute fracture of the posterolateral process of the talus can also cause posterior ankle pain .
a Radiograph of a 13-year-old dancer with posterior impingement and a painful os trigonum. Note that the dancer is unable to achieve full demi-pointe position with weight bearing (i.e., she is unable to align her metatarsals under the tibia or get maximal ankle plantarflexion). b Radiograph of a 15-year-old dancer demonstrating the “en pointe” position of the foot. Although this dancer has a prominent Steida process, she had no impingement symptoms at the time of the radiograph, and could easily achieve maximal ankle plantarflexion
Dancers with posterior ankle impingement usually describe pain in the posterolateral ankle behind the fibularis tendons, along with stiffness and limitation in plantar flexion motion. Pain is worse with plantar flexing of the foot, as in tendu and relevé maneuvers. This condition may be mistaken for fibularis or Achilles tendonitis, and may follow an ankle sprain . An affected dancer may have difficulty achieving the full pointe position on the affected side. Swelling and tenderness may be present behind the lateral ankle joint anterior to the Achilles tendon. Dancers with posterior ankle impingement will have a positive plantar flexion sign: pain with forced passive ankle plantar flexion with the dancer’s knee flexed at 90° will reproduce the symptoms. This test will not be positive in Achilles, fibularis, or isolated FHL tendinitis [53–57, 60–63]. Those with FHL tendonitis and an os trigonum will have posteromedial ankle tenderness and pain with flexion of the great toe against resistance. Palpable crepitus just posterior to the medial malleolus may be found with range of motion of the great toe. Triggering or locking of the great toe may be present [62, 63].