Keywords
The field of dance medicine has grown immensely over the last more than 20 years. Dancers, such as ballet, jazz, modern, tap, or competitive ballroom dancers, are artists and athletes. In dance, the choreographer acts as a sculptor, using the dancer as a medium of expression. This often entails placing the dancer’s body in positions that require extraordinary flexibility and movement, which need controlled power and endurance. All forms of dance are highly demanding activities, with a lifetime injury incidence of up to 90%. Most dance types are stressful, particularly on the dancer’s forefoot, but certainly, and there is no area of the foot or ankle that is exempt from potential injury.
Who is a typical dancer? In reviewing the literature, both peer-reviewed and trade publications, a profile appears for professional and competitive ballroom dancers.
In a study by Weiss and colleagues,
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a profile was developed as to the demographics and background of a typical modern dancer. They found that modern dancers are a unique group of artists, performing a diverse repertoire in dance companies of various sizes. The mean age of the dancers was 30.1 ± 7.3 years and they had danced professionally for 8.9 ± 7.2 years. The average body mass index (calculated as the weight in kilograms divided by the height in meters squared) was 23.6 ± 2.4 for men and 20.5 ± 1.7 for women. Women had started taking dance classes earlier (age, 6.5 ± 4.2 years) as compared with men (age, 15.6 ± 6.2 years). Women were more likely to have begun their training in ballet, whereas men more often began with modern classes (55% and 51%, respectively; P<.0001). In a survey, the professional modern dancers were found to spend 8.3 ± 6.0 hours in class and 17.2 ± 12.6 hours in rehearsal each week. It was reported that 50% took modern technique class and 67% took ballet technique class. The dancers (N = 84) who specified what modern technique they studied reported between 2 and 4 different techniques. The dancers also participated in a multitude of additional exercise regimens for a total of 8.2 ± 6.6 hours per week, with the most common types being Pilates, yoga, and upper body weight lifting. The dancers wore many different types of footwear, depending on the style of dance being performed. For modern dance alone, dancers wore 12 different types of footwear. Reflecting the diversity of the dancers and companies surveyed, women reported performing for 23.3 ± 14.0 weeks (range, 2–52 weeks) per year, whereas men reported performing 20.4 ± 13.9 weeks (range, 1–40 weeks) per year.A meta-analysis by Hincapié and colleagues
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determined that there is a high prevalence and incidence of lower extremity and back injuries, with soft tissue and overuse injuries predominating. For example, lifetime prevalence estimates for injury in professional ballet dancers ranged between 40% and 84%, whereas the prevalence of minor injury in a diverse group of university and professional ballet and modern dancers was 74%. Adolescent dancers account for most ballet injuries.Among the injuries, 53% occurred in the foot/ankle, 21.6% in the hip, 16.1% in the knee, and 9.4% in the back. There were 1.09 injuries per 1000 athletic exposures, and 0.77 injuries per 1000 hours of dance. Significant differences between injured and noninjured dancers were limited to the history of low-back pain (P = .017), right foot pronation (P = .005), insufficient right-ankle plantar flexion (P = .037), and lower extremity strength (P = .045). In a study of Irish dancers by Walls and colleagues,
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only 3 ankles out of 18 were considered radiologically normal. Achilles tendinopathy, usually insertional, was the most frequent observation (n = 14), followed by plantar fasciitis (n = 7), bone edema (n = 2), and calcaneocuboid joint degeneration (n = 2). There were limited correlations between magnetic resonance imaging (MRI) patterns and clinical scores, indicating that many conditions are subclinical. According to Kadel,4
the reported injuries occurred in 67% to 95% of ballet dancers and 17% to 24% of modern dancers. Of all dance injuries reported, 34% to 62% are foot and ankle injuries. Female ballet dancers reported more injuries than male ballet and modern dancers, and 23% to 45% foot and ankle injuries in professional musical theater dancers.No specific demographic data have been developed on competitive ballroom dancing; however, trade information reveals that there is a growing group of 40- to 70-year-old men and women participating in ballroom dancing. The information does not segregate or stratify between competitive ballroom dancing versus noncompetitive dancing. However, the latest trend is an aerobic dance trend called Zumba, a fusion of Latin and international music that creates a dynamic cardio workout. The overall incidence of dance injuries across the spectrum of dance styles varies widely, with a reported annual frequency of 23% to 85% of participants suffering a injury of that percentage; 65% are secondary to overtraining and 35% to trauma.
Biomechanics of the foot in dance
In any form of dance, great strain is placed on the lower extremity and the foot. A large percentage of injuries to dancers involve the foot and ankle. Understanding the structure, biomechanics, and physics of the lower extremity helps to diagnose and evaluate the mechanics behind these injuries. The lower extremity function is complicated and needs to be studied carefully to understand its laws and principles. For example, relevé can cause sickling and put the foot in an unstable position if there is forefoot instability, such as decreased stiffness of the medial column or a functional or structural hallux limitus or rigidus. If the forefoot is not strong enough, then the leg will externally rotate and the hip joint’s muscular support will not be stable during heel raise. In the opposite direction, when a dancer is executing plié, the outcome of an unstable foot is strain on the passive supporting structures, such as the plantar fascia, midtarsal joint capsules, and tarsometatarsal joint complex (Lisfranc joint). This strain leads to faulty bone alignment, increased load when the foot structure is not aligned to dissipate it across a broader surface, and risk of overuse injury.
The en pointe position of maximal plantar flexion through the forefoot, midfoot, and hindfoot requires tremendous flexibility and strength that can only be attained safely through many years of training.
Biomechanically evaluating the function is critical to developing a differential diagnosis and identifying the cause for any type of dancer. The shoe that is required for each type of dance must also be evaluated. There are many companies that fabricate a variety of shoes for each dance specialty. It is only recently that dance shoe manufacturers have started to incorporate biomechanical design features. For example, Capulet has redesigned the ballet pointe shoe to reduce abrasions, reduce impact force, and improve stability as well as by stiffening the shank. Each category of dance must be aesthetically pleasing in addition to being functional for the particular dance style. Competitive ballroom dancing has subcategories for men and women. Many of these dancing shoes are fitted tightly to the foot and leave little room for accomodations to treat biomechanical and structural deformities. Dance shoe evaluation is not only critical to the diagnostic evaluation of a patient’s problem but also an integral part of the treatment plan.
Other risk factors that must be considered and related to the dancers foot type and function are dancing barefoot, long training hours, increased flexibility, lifts and throws, increased rotational torque, and insufficient support either mechanically or from shoes.
Dancer evaluation and examination
Evaluating dance injuries should be as extensive as any sports injury. The physician must take a careful history including an attempt to understand the mechanism of injury, the patient’s preinjury level of activity, history of prior injuries, evaluation of the shoe gear, the type of dance, the frequency and intensity of practice, and the competition or performance schedule, as well as what other activities does the patient participate and what type of shoe gear is used for those activities.
Physical examination includes comparing the unaffected foot with the injured foot, putting each part of the foot through its range of motion, doing active and passive muscle testing and gait analysis, and if possible, evaluating the position or positions that cause the pain. Lastly, having the dance-specific shoe put on while evaluating the fit of the shoe and then doing a dance analysis, if possible, with the dance shoe on, thus recreating the problem.
Imaging
Diagnostic ultrasonography is a significant tool for this type of patient who typically has soft tissue overuse–type injuries. The tendon and fascial structures are clearly visualized with diagnostic ultrasonography. The metatarsophalangeal (MTP) joint’s plantar structures, ganglions, and neuromas can also be clearly visualized using diagnostic ultrasonography.
The use of computed tomography (CT) and MRI has certainly improved the diagnostic specificity of most overuse injuries when compared with plain radiographic evaluation. In a study by Russel and colleagues,
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the ballet dancers’ ankles weight bearing maximum plantar flexion (en pointe) were evaluated to assess whether the pathologic findings of MRI were associated with ankle pain reported by the subjects. In this study, 9 female ballet dancers (age, 21.0 ± 2.9 years; dance experience, 16.0 ± 4.1 years; en pointe dance experience, 7.0 ± 4.9 years) completed an ankle pain visual analog scale questionnaire and underwent T1- and T2-weighted scans using a 0.25-T open MRI device. The ankle was scanned in 3 positions: supine with full plantar flexion, standing with the ankle in anatomic position, and standing en pointe.MRI signs of ankle abnormality and anatomic variants were observed. Convergence of the posterior edge of the tibial plafond, posterior talus, and superior calcaneus was noted in 100% of cases. Widened anterior joint congruity and synovitis/joint effusion were present in 71% and 67%, respectively. Anterior tibial and/or talar spurs and Stieda process were each seen in 44%. However, clinical signs did not always correlate with pain reported by the subjects.
Certainly, many other studies have been completed, reporting a multitude of pathologic conditions that have a commonality with the typical dance injuries, and it is beyond the scope of this article to review the CT and MRI literature for foot and ankle injuries.
Commonly reported dance-related injuries and treatment highlights
- •Fractures varying from incomplete stress fractures to a full comminuted fracture, with no osseous structure exempt from potential injury
- •Structural deformities including hallux abducto valgus, hallux limitus, hallux rigidus, and contracted digital deformities. Impingement syndromes (anterior and posterior) of the ankle. Chondral injuries, such as Freiberg disease, and osteochondral avascular necrosis
- •Overuse injuries including tendon and fascial injuries, that is, plantar fasciitis, Achilles tendinitis, Achilles enthesopathy, tenosynovitis of the flexors and/or extensors, and shin splints
- •Sprains and strains of the ankle and subtalar, midtarsal, tarsometatarsal (Lisfranc joint), and MTP joints.
Discussion of commonly reported dance injuries (in the order of frequency)
Ankle Sprain
Ankle inversion injuries are the most common traumatic injuries in dancers. The lateral ligament complex of the ankle is the most frequently injured structure in the body. Although most simple ankle sprains do not result in long-term disability, a significant number do not completely resolve, leading to residual symptoms that may persist for years. Ankle stability is integral to normal mobilization and to minimizing the risk for ankle sprain. The ability of the dynamic and static stabilizers of the ankle joint to maintain their structural integrity is a major component of the normal gait cycle. Hiller and colleagues
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attempted to identify intrinsic predictors of lateral ankle sprain and they evaluated 115 adolescent dancers, 94 female and 21 male. They found that in the test group, an increased risk of sprain was predicted by younger age, previous sprain of the contralateral ankle, increased passive inversion range, and the inability to balance on demipointe. Of these predictors, only previous sprain of the contralateral ankle significantly predicted ankle sprain in the validation group. The most commonly reported symptoms, particularly among athletes, include instability, reinjury, and tendinitis. For example, ballet dancers perform in unusual positions, such as en pointe, that place the ankle in extreme plantar flexion, requiring stabilization by surrounding muscles. Dancers’ extraordinary performance demands place them at risk for other ankle injuries as well, including inflammation of the Achilles tendon, peroneals, and flexor hallucis longus (FHL) most notably. A literature review by Ritter and Moore7
reports that numerous studies have investigated ankle sprains and residual complaints, and nearly all studies report that lateral ankle sprains commonly lead to chronic ankle instability. Studies exploring ankle stability have demonstrated that the peroneal muscles play a crucial role in ankle stabilization; electromyographic (EMG) studies confirm that ankle stability is the first to occur during ankle inversion stress. The dancer’s need for exceptional ankle stabilization may lead to peroneal overuse and tendinitis. Studies have linked peroneal abnormality to a history of ankle sprain, but there is no dance medicine literature linking peroneal tendinitis to prior ankle sprains. A growing body of literature confirms myriad connections between lateral ankle sprains, residual instability, peroneal muscle increased activity, and tendinitis. Ritter and Moore7
concluded that ankle sprains lead to instability, particularly en pointe, for which the peroneal muscles attempt to compensate. Peroneal muscle overuse for this static stabilizing function, as well as for dynamic dance movements, then leads to tendonitis.Symptoms described by dancers when they initially present with an ankle injury are rolled ankle, hearing a “pop” type sound, and swelling and bruising over the lateral ankle, typically occurs after landing with a jump or after a combination of rapid leg movements.
The role of a typical physical examination is to evaluate the lateral collateral ligaments with an anterior drawer test (requires stabilizing the tibia, attempting to bring the talus forward in the mortise, and noting any anterior displacement). Physical examination also includes palpating the lateral collaterals for pain or instability. The examiner should evaluate and attempt to differentiate ankle injury from subtalar joint pain and identify whether the pain is localized at the lateral collaterals or more in the sinus tarsi than the peroneal tendons.
Imaging at this point is extremely important; plain radiography is performed first to rule out osseous pathologic conditions such as stress fracture, acute complete fracture, structural alignment issues, and the presence of Stieda process. Then a diagnostic ultrasonography would be appropriate to image the peroneal tendons and lateral ankle collaterals. Lastly, an MRI can be performed especially in a professional or competitive dancer to isolate the specific area of injury.
Initial therapy for ankle injury is (1) full evaluation, (2) compression using a compression stocking or an equivalent at a pressure of 15 to 20 mm Hg, (3) stabilization using a stiff controlling brace such as AirSport (Aircast) or an equivalent, and (4) contrast temperature therapy using cold application for 10 minutes, followed by heat application for 10 minutes, and then completing the set with a second cold application for 10 minutes. The process of contrast temperature therapy is repeated 4 to 5 times per day for the first 5 days and is then reduced to twice a day until the injury is resolved or imaging studies are completed. A full understanding of the injury is then completed, and a full treatment plan is developed.
Follow-up therapy includes proprioceptive strengthening exercises, possible diagnostic or therapeutic ankle arthroscopy, physical therapy including infrared laser treatment at 800 to 980 nm, ultrasonography, and exercise rehabilitation to return to full strength preinjury level. Additionally, the dancer biomechanics would be assessed and shoe evaluation would be completed to determine if a biomechanical device or modification to the dance shoe is necessary for injury prevention.
Dancers fracture, also known as spiral fracture of the fifth metatarsal base, typically occurs by rolling off pointe or by landing on the lateral aspect of the foot after a jump. Fifth metatarsal fractures are also common with ankle sprains.
The current gold standard for treatment of chronic fracture nonunion in the metaphyseal-diaphyseal region of the fifth metatarsal is intramedullary screw fixation, plating, or tension wire technique. Complications with these procedures, however, are not uncommon. Shock wave therapy can be an effective alternative treatment of fracture nonunions. In a study by Furia and colleagues,
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20 of 23 nonunions in the shock wave group and 18 of 20 nonunions in the screw fixation group were healed at 3 months after treatment. One of the 3 nonunions that were not healed by 3 months in the shock wave group was healed by 6 months. There was 1 complication in the shock wave group (posttreatment petechiae) and 11 complications in the screw fixation group (1 case of refracture, 1 cellulitis, and 9 symptomatic hardware). Both open reduction and internal fixation (ORIF) and shock wave therapy are effective treatments of fracture nonunion in the metaphyseal-diaphyseal region of the fifth metatarsal. ORIF is more often associated with complications that frequently result in additional surgery.Hallux Limitus/Rigidus
A limitation of motion in the first MTP joint can be attributed to several causes including a functional hallux limitus secondary to decreased stiffness of the first ray; with weight bearing, the first ray effectively elevates and the MTP joint is locked. Thus, the hallux cannot dorsiflex on the first metatarsal, forcing the foot to externally rotate and roll off the medial aspect of the hallux; however, in some patients, the hallux interphalangeal joint is forcibly dorsiflexed. Causes of hallux rigidus are also multifactorial; ultimately it can be considered on a continuum with functional hallux limitus. Grading is dependent on the extent of degeneration of the articular surfaces, progressive over time due to the repetitive jamming within the first MTP joint.
Modern, jazz, and ballet dancers complain of the pain in MTP joint earlier than a tap dancer because the shoes and the movements do not require as much motion in the first MTP joint and the shoe sole is much stiffer. Ballet dancers notice the restriction of motion especially in full relevé. Ballet dancers compensate with sickling during demipointe, which is not an acceptable alignment and can lead to lateral ankle sprains.
Modern, jazz, and ballroom dancers notice restriction with any dance step or jump that requires push off. The effects of hallux limitus/rigidus are more common among dancers who began dancing at an older age.
Treatment of hallux limitus should begin as early as possible, ensuring excellent function of the peroneus longus, which assists in stabilization of the first ray. Treatment can be performed with proprioceptive exercises, functional foot orthosis, and range of motion exercise of the MTP joint.
If the treatment fails and the limitation of motion continues to develop, then surgical options should be explored, including stabilization of the first ray with arthrodesis of the first metatarsal cuneiform joint and plantar-flexed position of the first metatarsal, possible gastrocnemius recession to achieve lengthening of the Achilles tendon and reduce equinus deformity, or subtalar artheroresis to control rearfoot motion and position during gait and dance. If the limitation of motion has progressed to rigidus and there is osteophytic proliferation around the metatarsal head and base of the proximal phalanx, then cheilectomy or other procedures including joint replacement may need to be considered.
Hallux Abducto Valgus and Turf Toe
Injuries to the MTP joint of the great toe have increased in incidence over the past 30 years following the introduction of artificial playing surfaces and the accompanying use of lighter footwear. Although these injuries are most common in American football players, similar injuries can also occur in other sporting activities including soccer and dance or after trauma to the great toe. The mechanism of injury is typically hyperextension of the MTP joint, but injuries have also been reported secondary to valgus or varus stress or rarely as a result of hyperflexion. The abnormal forces applied to the first MTP joint during injury result in varying degrees of sprain or disruption of the supporting soft tissue structures, leading to the injury commonly referred to as turf toe. The extent of soft tissue disruption is influential in treatment planning and can be used to determine the prognosis.
As with hallux limitus and rigidus, treatment should start early in a dancer’s career, addressing the mechanical deficiencies in the foot structure and focusing on improving the stability of the medial column to prevent decreased stiffness of the medial column. When decreased stiffness develops in the medial column, there is an effective elevation of the first ray with weight bearing and this elevation limits motion at the first MTP joint. Over time, this jamming causes degeneration of the cartilaginous surfaces and osteophytic proliferation, moving from available motion and a viable joint space to the end point of severe degenerative arthritis with loss of the joint space within the first MTP joint.
Initially, the dancer needs to focus on reducing posterior muscle tightness (equinus) and maintaining good strength in the peroneal muscle group. Pronatory forces at the subtalar joint are reduced by using a functional foot orthotic, inverting the calcaneal position and loading the lesser metatarsals, and allowing the first ray to function in a more plantar-flexed position. To make a device to fit in a ballet slipper or pointe shoe, it can be fabricated from carbon graphite for minimal thickness and maximal structure and narrow arch area, allowing the heel cup to be wedged inverted (varus, higher medial than lateral) and molded in the forefoot depending on the foot type to hold the forefoot in neutral and allow the first ray to plantar flex as the forefoot loads. Several different modifications can be added to the forefoot placed on an extension from the orthotic to the toes. Using a kinetic wedge as described by Dananberg
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or reverse the Morton extension, these devices effectively increase the range of motion at the first MTP joint as the forefoot is loaded.Ultimately, if the progress cannot be slowed sufficiently, then surgical intervention should be considered which may include arthrodesis of the first metatarsal cuneiform joint to plantar flex the first metatarsal to achieve medial column stability with cheilectomy of the osteophytes that have developed around the metatarsal head and base of the proximal phalanx hallux. In an unpublished proof-of-concept (Bruce Werber, DPM, 2009) small group study of 12 patients with hallux limitus, who had a joint space and minimal osteophytic proliferation on radiographs, continued to have joint pain despite the use of appropriate foot orthotics. Their joints were injected with 1.5 mL of autogenous platelet-rich plasma (PRP). After 12 weeks, they reported a significant 80% to 90% reduction in joint pain, which has been effective for 40 weeks on average.
Metatarsalgia
Metatarsalgia is described as forefoot pain that is associated with increased stress/pain in the area of the metatarsal head region. Metatarsalgia is often referred to as a symptom rather than a specific disease. Differential diagnoses of metatarsalgia include interdigital neuroma, MTP synovitis, avascular necrosis, sesamoiditis, and inflammatory arthritis. Female competitive ballroom dancers seem to have a higher incidence of forefoot complaints than other types of dancers. This incidence is attributable to the types of shoes that are typically high heels with very thin soles and extremely tight fit, as well as the motions performed in certain turns and steps, requiring persistent weight focused on the forefoot.
The most common findings and diagnoses in order of frequency as noted in the author’s clinic are discussed in the following sections.
Neuritis/nerve entrapment is the most common finding. Dancers are required to perform at the extreme of their physiologic and functional limits. Under such conditions, peripheral nerves are prone to compression. Entrapment neuropathies in dancers can occur at multiple levels. The most common nerve disorders encountered in dancers include interdigital neuromas (second and third interspaces), tarsal tunnel syndrome, anterior tarsal tunnel syndrome, superficial and deep peroneal nerve entrapment, and sural nerve entrapment.
Treatment of these nerve disorders begins with their diagnosis using ultrasonography, MRI, or neurologic testing; in some cases, diagnostic nerve blocks are performed to isolate the cause of pain. Once the abnormality is identified, the treatment protocol is then to address the its mechanics if one exists and to decompress the nerve with physical therapy, change in technique or shoe, or with steroid injection, sclerosing injections of absolute alcohol,
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or surgical decompression.11
Sesamoid injuries of the first metatarsal phalangeal joint in dancers may result in prolonged pain, disability, and career limitation. A thorough understanding of sesamoid function and potential disorders is critical for all dancers, including aerobic, ballroom, and certainly, performance dancers. Sesamoid disorders are common causes of the forefoot pain metatarsalgia. There are significant mechanical stresses and anatomic variations reported and noted regarding the sesamoid complex. Numerous pathologic processes can affect the sesamoid apparatus of the first metatarsal phalangeal joint. These processes include acute fractures, stress fractures, nonunions, osteonecrosis, chondromalacia, and various inflammatory conditions that are grouped as sesamoiditis that is typically caused by synovitis.
Treatment includes activity and weight-bearing restrictions, protective padding, strengthening, functional retraining, and progressive return to dance. Injections of steroid must be used judiciously; bone stimulators have been reported to be successful in the treatment of stress fractures and complete fractures of the sesamoids. This is another area that can be potentially treated with PRP, with minimal risk. The potential loss of hallux plantar-flexion strength due to sesamoidectomy is a major consideration for dancers, and thus, sesamoidectomy should be a procedure of last resort.
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Capsulitis and rupture of the plantar plate in lesser metatarsal phalangeal joints potentially lead to the formation of contracture of the proximal interphalangeal joints (hammer toe deformity).
Examination reveals tenderness and palpable fullness of the metatarsal phalangeal joint, painful dorsal drawer sign, adjacent interdigital tenderness, and developing nonrigid hammer toe deformity. Radiography may reveal mild to significant subluxation of the metatarsal phalangeal joint, with the proximal phalangeal base drifting medially or laterally. Diagnostic ultrasonography may reveal rupture of the plantar plate at its attachment to the base of the proximal phalanx, swelling of the flexor tendon, or swelling within the joint itself or a combination of any or all of these findings. Treatment includes intra-articular corticosteroid injection but must be used with caution because the fluid load of the lesser MTP joints is typically less than 1 mL and there is a risk of intrinsic tendon rupture, accelerating capsule tearing, or plantar plate rupture. The use of Budin splint helps reduce pressure and irritation and aligns overlapping digits while encouraging extension of flexible hammer or claw toes during gait. Temporary rocker-sole shoe modification to limit MP joint dorsiflexion helps to off-load the pressure. Restriction and modification of activity is a useful adjunct initially. Surgical options include open arthrotomy with synovectomy, using radio frequency coblation to perform synovectomy and repair plantar plate instability, shortening osteotomy of the metatarsal by performing an oblique osteotomy as described by Weil, and arthrodesis of the proximal interphalangeal joint and flexor transfer. These procedures are successful but must be used with caution in any dancer.
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Freiberg disease, or osteonecrosis of the second metatarsal head, is an uncommon cause of forefoot pain that can severely limit a dancer’s relevé. Dancers may be predisposed to the condition because of repetitive microtrauma to the ball of the foot during routine dance movements. Freiberg disease is diagnosed by history taking, physical examination, and plain film radiography. Conservative treatment in dancers is disappointing, and surgical options fail to produce uniformly good results.
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Several alternatives have been reported including an open arthrotomy of the second MTP, a synovectomy using radio frequency coblation under arthroscopic visualization, or injecting the joint with 1 mL of PRP and have protected weight bearing off-loading the forefoot for 2 to 3 weeks, then starting physical therapy and gradual return to activity.15
Miscellaneous forefoot complaints that can be concerning and disabling are ingrown toenails with or without infection, subungual bleeding, cracking or breaking of nails, and fungal infections of the skin or nails. Skin injuries are irritating should the dancer develop a blister or corns (hyperkeratosis) on the dorsal aspect of the proximal interphalangeal joints, and included in painful irritations is a viral infection causing a verruca (wart).
Treatment of warts and ingrown nail problems is fairly straightforward and is beyond the scope of this article to review. As far as the development of painful callus or porokeratosis, treatment can be fairly straightforward with periodic debridement, surgical correction of the causative deformity, or as advocated by Balkin,
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an intradermal injection of liquid silicon (Silikon 1000, Alcon, Fort Worth, TX, USA). Balkin’s work has been documented over 40 years using liquid silicon and he has reported significant resolution of painful hyperkeratosis without surgery and solely with injection of liquid silicon intradermally.Heel Pain, Plantar Fasciitis, Plantar Fasciosis, Heel Spur Syndrome
Heel pain cannot always be assumed to be caused by the pathologic condition in the plantar fascia. It is imperative that all potential causes be investigated and ruled out. Differential diagnosis consists of tarsal tunnel syndrome, entrapment of the medial calcaneal nerve, lumbar radiculopathy, compartment syndrome of the medial and plantar compartments of the foot, rare primary presenting sign of systemic inflammatory disorders, Achilles enthesopathy, stress fracture, bone tumor, and space-occupying lesions.
The cause of heel pain in a dancer is multifactorial; starting from the surface the dancer is working on. For example, whether the floor is sprung or nonsprung; if the floor is hard and unyielding, there will be more force on the foot as the dancer lands and thus increasing strain on the plantar fascia. If the dancer wears heels outside the dance practice and performance arena, then the posterior muscle group can tighten and contribute to increased pronatory forces being created along the plantar fascia.
Diagnosis of heel pain is essential to getting dancers back to their activity. Radiography is essential to evaluate osseous structures and ultrasonography is a tremendous tool to evaluate the plantar fascial thickness. Normal fascia is typically recognized to be approximately 2.5 to 3.5 mm thick at the calcaneal insertion, but as the thickness increases, the fascia becomes scarred and thickened worsening from an inflammatory state to a chronic thickened poorly vascularized state considered to be fasciosis. Lemont and colleagues
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reviewed histologic findings from 50 cases of heel spur surgery for chronic plantar fasciitis. Findings included myxoid degeneration with fragmentation and degeneration of the plantar fascia and bone marrow vascular ectasia. Histologic findings were presented to support the hypothesis that plantar fasciitis is a degenerative fasciosis without inflammation and not a fasciitis. In the studies by Almekinders18
from 1998 through 2002, he demonstrates clearly that there is minimal inflammatory response within the tendon and fascia after direct tissue injury and that there is no inflammatory response in the tissue that has suffered repetitive motion–type injuries. Khan used a rat model to produce acute tendinopathy by exposing the tissues to proinflammatory cytokines. The tissues demonstrated no inflammatory response but did show derangement and degradation of the collagen fibers.Diagnostic studies for the other differentials include MRI, CT scan, EMG, nerve conduction velocity studies, and possibly, bone scans to fully evaluate the causative factors. The diagnostician must look proximal as well to identify possible causes of heel pain especially in a dancer, for example, lumbar stenosis causing radiculopathy.
Treatment of heel pain varies from modification and change of the types of shoes worn during dancing and nondancing activities to aggressive stretching of the gastrocnemius and soleus and the plantar fascia and intrinsics of the foot. Steroid injections and foot orthotics have been a mainstay in treating plantar fasciitis and fasciosis. New technologies such as radio frequency coblation and injection of PRP show significant promise in combination with traditional therapeutic approaches. Near-infrared diode laser therapy in the frequency range of 800 to 980 nm show significant potential in stimulating the tissue to heal.
When using orthotics for dance shoes, all dance shoes must fit snugly and must be cut narrow and tight to the foot. Pointe shoes are the most difficult to accomodate for any type of biomechanical correction. At times, gluing accommodations directly into the shoe works best or using extremely thin poly prefabricated devices and modifying those shells that typically are 1 to 2 mm in thickness has worked well to stabilize the foot in the pointe shoe. In ballroom, jazz, and tap shoes for men, it is much easier to add thin poly or carbon graphite shells with intrinsic corrections built into the orthosis. It is extremely difficult to modify or accommodate a removable type of orthosis in ballroom shoes for women. In these cases, a shoe repair expert can help to build and modify the inner sole of the shoe, along with the pads and straps to improve foot function.
Achilles Tendinitis, Enthesopathy, and Haglund Deformity
These conditions present with pain in the posterior lower leg and heel. The differentiation between the 3 diagnoses depends on location. Achilles tendinitis or tendinopathy that is found typically 3 to 6 cm from the Achilles tendon insertion presents as a dull ache or discomfort and expands to a nodule within the Achilles tendon, with a feeling of crepitus as the foot is dorsiflexed and plantar flexed. There is swelling and inflammation around the painful area of the tendon. Achilles tendon injuries are typically caused by overtraining to perform relevé and jumps, a case of too much too soon associated with a lack of flexibility of the calf muscles.
The tendon experiences a similar course of events as the plantar fasciosis, with an initiating event occurring to injure the tendon. Initially, an inflammatory reaction occurs, but because of the continued activity or intake of antiinflammatory medications, the normal healing process is interrupted and instead of a healthy tendon a poorly vascularized thickened scar-like tissue is formed. Achilles enthesopathy occurs at the insertion. This condition is typically caused by either repetitive sudden forces at the insertion or chronic equinus with pulling and tearing of the Achilles insertion with reactive bone formation within the tendon insertion. Haglund deformity typically becomes apparent when there is chronic irritation from the shoe on the posterosuperior surface of the calcaneus, resulting in bursa formation and then chronic pain on the posterosuperior aspect of the heel.
Achilles tendon rupture does occur in dancers but is a rare occurrence and must always be in the differential list and ruled out via MRI or diagnostic ultrasonography.
Treatment of Achilles tendinitis and enthesopathy is similar to treating heel pain and is followed by stretching, near-infrared laser therapy, and/or PRP injection if the tendon injury does not respond to the traditional therapy of rest, bracing, and physical therapy. Certainly, using appropriate diagnostic modalities is necessary to confirm the diagnosis; MRI or ultrasonography is an excellent option for visualizing the tendon. If the patient does not respond to conservative modalities, including PRP injection and laser therapy, then an open surgical approach may be necessary to resolve the chronic intractable condition. During surgery for chronic nodule formation and intractable tendinopathy, a posterolateral approach is taken; the tendon is inspected and incised, resecting the poorly organized and formed tissue, radio frequency coblation is performed, and a primary repair is done. This surgical approach is applied for Achilles enthesopathy as well; in addition to repairing the distal tendon, the reactive bone is resected as well, and the author uses knotless anchors to reattach the tendon to the calcaneus.
Ankle Posterior Impingement Syndrome
This syndrome is an impingement at the posterior of the ankle between the talus and tibia. It is also known in the literature as os trigonum syndrome, talar compression syndrome, posterior ankle impingement syndrome, and posterior tibiotalar impingement syndrome.
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The posterior tubercle or elongated posterolateral talar process (Stieda process) of the talus can effectively be pinched between the talus and tibia, causing pain. Hypertrophy or tear of the posteroinferior talofibular ligament (TFL), transverse TFL, tibial slip, or pathologic labrum on the posterior ankle joint can lead to posterior ankle impingement, which can affect the os trigonum or posterior talus of the calcaneus. Shepherd fracture is a synchondrosis of the os trigonum or a fracture of the posterior or trigonal process of the talus.26
The dancer describes pain and tenderness at the back of the ankle. Pain is triggered when the ankle is passively plantar flexed to the extreme range of motion. A local anesthetic block injection is given to the affected area, and if passive plantar flexion no longer triggers pain, it is an indication of impingement. This syndrome can also result from abnormality of the os trigonum–talar process, ankle osteochondritis, FHL tenosynovitis, and subtalar joint disease. Pain is elicited by forced plantar flexion and push-off maneuvers.
27
In ballet dancers, forcing a turnout of the foot can predispose to this condition.27
Hardaker28
found that in extreme plantar flexion, an os trigonum, a Stieda process, a prominent dorsal process of the calcaneus, or the presence of adhered or loose osteophytes can occupy space within the posterior ankle joint and lead to soft tissue impingement.Hamilton
29
described a labrum or pseudomeniscus of the posterior lip of the tibia, which can become torn or hypertrophied with ankle sprains and lead to posterior impingement. Excessive plantar flexion at the ankle joint can cause compression of the posterior synovial, capsular, and/or ligamentous tissues against the posterior tibia. With repeated entrapment, the posterior soft tissue structures can undergo inflammatory changes, thickening, and fibrosis, leading to scarring and/or calcification.30
, 31
, 32
FHL tendinopathy is a common injury especially in ballet dancers who function frequently en pointe and is included in the differential of posterior impingement syndrome. Repetitive and prolonged plantar flexion leads to tenosynovitis or tendinopathy. Further overuse frequently progresses to frank longitudinal tearing. As in any tendinopathy, there is a thickening of the tendon initially secondary to inflammation, and as the injury goes untreated, the tendon thickens and synovitis develops. As the tendon passes into the flexor sheath in the posterior aspect of the ankle, the thickened tendon essentially gets caught on the edge of the tendon sheath. Inflammation of the FHL tendon generally can occur in one of the following areas: at the fibro-osseous tunnel along the posteromedial ankle, under the base of the first metatarsal where the flexor digitorum longus tendon crosses the FHL tendon (knot of Henry), or where the FHL tendon passes between the great toe sesamoids beneath the metatarsal head.
When the tendon becomes nodular, triggering of the great toe (hallux saltans) can occur and lead to hallux rigidus. Complete tears of the FHL tendon are infrequent, with fewer than 4 cases of acute rupture being reported.
Symptoms described by the dancer include a feeling of the hallux clicking or getting caught, and the dancer will be unable to move into en pointe due to a sense of having no strength and also pain while lowering from demipointe.
Ankle Anterior Impingement Syndrome
This syndrome is an impingement at the anterior portion of the ankle between the talus and tibia. The characteristics of the syndrome are restriction of full plié on one side, pain with deep pliés, swelling may be noted at the anterior ankle joint, and osteophytes may be noted on the anterior aspect of the tibia or the neck of the talus. Bassett and colleagues
33
found and described a separate pathologic fascicle of the anterior TFL in syndesmotic impingement. Following a tear of the anterior TFL, the anterolateral talar dome extrudes anteriorly with dorsiflexion, resulting in impingement. Chronic repetitive microtrauma can lead to bone spur formation (anterior tibiotalar osteophytes), which gradually causes subsequent limitation of movement and pain. The development of anterior ankle impingement in ballet dancers requires hyperdorsiflexion to accomplish the demiplié position, which, in turn, can lead to direct contact and impingement of the anterior lip of the tibia on the talar neck.34
, 35
Repetitive impingement secondary to extreme dorsiflexion proliferates exostosis formation at the anterior ankle joint.28
, 36
Conservative treatment of ankle impingement syndromes includes modifying activity, wearing protected bracing or casting, immobilization by rest, physical therapy, heel lifts, dance and regular shoe modifications, antiinflammatory medication, and corticosteroid and PRP injections. If conservative measures fail and the patient continues to experience swelling, tenderness, limitation of motion, and weakness, then surgical management should be considered.
Reach and colleagues
37
investigated the degree to which ultrasonographically guided injections could accurately reach the common foot and ankle injection sites. Using ultrasonographic guidance, a methylene blue–saline mixture was injected into 10 fresh cadaver feet, targeting the FHL sheath as well as the first and second MTP joints, the tibiotalar joint, the Achilles peritendinous space, the posterior tibial tendon sheath, and the subtalar joint. It was reported that the injections for all sites were 100% accurate, whereas that of the subtalar joint was 90% accurate.Open and arthroscopic techniques have been described for the management of anterior and posterior ankle impingement syndromes. Scranton and McDermott
38
did a comparison of open versus arthroscopic measures for anterior ankle impingement, demonstrating that arthroscopy yielded shorter period of postoperative hospitalization and recovery time.In a retrospective study, Nihal and colleagues
39
reviewed arthroscopic treatment of the anterior bony and soft tissue impingement of the ankle in elite dancers. Out of the 12 patients, 9 returned to full dance activity at an average of 7 weeks after surgery. It was concluded that arthroscopic debridement is an effective method for the treatment of bony and soft tissue anterior ankle impingement syndrome in dancers and has minimal morbidity.40
, 41
, 42
, 43
The objective for surgical treatment of posterior ankle impingement is excision of the impeding anatomic structure. An open medial approach is recommended if the pathologic condition affects the FHL tendon (eg, tear, tenosynovitis) in addition to posterior bony impingement, whereas a lateral approach would be appropriate if the abnormality is primarily osseous., 20
, 44
Posterolateral Injuries
Calcaneocuboid joint subluxation and peroneal tendinitis
Cuboid syndrome is defined as a minor disruption or subluxation of the structural integrity of the calcaneocuboid portion of the midtarsal joint. This syndrome is also known as lateral plantar neuritis, cuboid fault syndrome, dropped cuboid, locked cuboid, and subluxed cuboid and is a common cause of lateral foot pain in the dancing population. The chief complaint is that of lateral foot pain and weakness during push off. The pain is described as radiating to the medial plantar aspect of the foot and/or to the anterolateral ankle joint or along the fourth and fifth metatarsals. The patient complaints of an inability to “work through the foot” while moving from a foot flat position to demipointe or a full en pointe position. This syndrome typically occurs acutely when dancers land from jumps or as an overuse syndrome from repetitive pointe work. It is thought that repetitive forces can lead to decreased stability of the midfoot and predispose dancers to cuboid syndrome.
45
, 46
, 47
Diagnosis of cuboid syndrome is difficult. Radiography, CT scan, and bone scans provide limited information; MRI has a higher diagnostic potential but has limitations. The physician must work through the differential diagnoses including sinus tarsi syndrome, lateral process fracture of the talus, acute tendinitis of the peroneus longus tendon, fracture of the anterior process of the os calcis, fractures (including stress fractures), fracture or dislocation of the os peroneum, and tarsal coalitions (in adolescents).
Treatment is difficult for this syndrome; several investigators suggest reducing the subluxed cuboid by using a manipulative technique, which is defined as a low-amplitude high-velocity mobilization at the end of joint range, to restore proper joint congruency. In addition to or as a primary treatment a cuboid pad can be applied directly under the cuboid and the patients’ body weight is used to manipulate the cuboid into a corrected position. A low-Dye taping with a cuboid pad has been suggested to hold the cuboid reduction and stabilize subtalar joint motion. Should these maneuvers be successful, a functional foot orthosis with an intrinsic cuboid raise or an additional pad can be fabricated.
The peroneal muscles make up the lateral compartment of the leg and are innervated by the superficial peroneal nerve. The tendon of peroneus longus courses behind the peroneus brevis tendon at the level of the ankle joint, travels inferior to the peroneal tubercle, and turns sharply in a medial direction at the cuboid bone. The tendon inserts into the lateral aspect of the plantar first metatarsal and medial cuneiform. The peroneus longus plantar flexes the first ray, everts the foot, and assists in plantar flexion of the ankle. A sesamoid bone called the os peroneum may be present within the peroneus longus tendon at about the level of the calcaneocuboid joint. The frequency with which an os peroneum occurs is approximately 20% of the population.
The peroneus brevis inserts onto the base of the fifth metatarsal and everts and plantar flexes the foot.
The peroneal tendons share a common tendon sheath proximal to the distal tip of the fibula. More distally, each tendon is within its own sheath. The common sheath is on the posterolateral aspect of the fibula. When the superior peroneal retinaculum (SPR) is intact, it prevents subluxation of the tendon. The hallmark of disorders of the peroneal tendons is laterally based ankle or foot pain with loss of eversion strength. Tenosynovitis and tendinous disruption (acute or chronic) as well as longitudinal tears of both the longus and brevis also occur. The brevis has been reported to be more susceptible to longitudinal tearing. The os peroneum may be involved with the degenerative process or a singular disorder and can be fractured or fragmented.
48
Brandes and Smith49
have reported that 82% of patients with primary peroneus longus tendinopathy had a cavovarus hindfoot. Overcrowding from a peroneus quartus muscle also has been reported. The mechanism of injury typically involves an inversion to the dorsiflexed ankle, with concomitant forceful contraction of the peroneals.Brandes and Smith
49
have described and classified primary peroneus longus tendinopathy into 3 anatomic zones in which the tendon can be injured. Zone A is the level of the SPR. Zone B is the level of the inferior peroneal retinaculum, typically partial ruptures. Zone C is the level of the cuboid notch where complete ruptures are most likely. Sobel and colleagues50
, 51
have presented a classification for tears of the peroneus brevis tendon as follows:- •Grade 1, flattened tendon
- •Grade 2, partial-thickness split less than 1 cm in length
- •Grade 3, full-thickness split less than 2 cm in length
- •Grade 4, full-thickness split more than 2 cm in length.
Eckert and Davis
52
have classified SPR abnormality as follows:- •Grade I, SPR elevated from fibula
- •Grade II, fibrocartilaginous ridge elevated from fibula with SPR
- •Grade III, cortical fragment avulsed with SPR.
The patient typically complaints of laterally based ankle or rearfoot pain increasing with activity and subsiding with rest. There usually is tenderness along the peroneal tendons. To evaluate the peroneal tendon stability, the patient’s foot is hung in a relaxed position with the knee at 90° and pressure is applied to the peroneal tendons posterior to the fibula. The patient is then asked to dorsiflex and evert the foot. Pain may be elicited and/or the tendons can be seen subluxing or examiner can feel the subluxation.
Conservative therapy includes modifying activity, modification or changing shoe gear, temporary immobilization, or bracing. Biomechanical therapy with functional foot orthosis adding valgus wedging reduces lateral stress. Consideration should be given to treating with electric stimulation, near-infrared laser therapy, and/or PRP injection with ultrasonographic guidance.
Surgical treatment is best considered under the specific pathology being addressed. With any procedure, it is important to remove abnormal-appearing synovium or tenosynovium. Tenosynovitis may be treated surgically with a simple division of the tendon sheath or radio frequency coblation. Care must be taken to protect the sural nerve. Brandes and Smith
49
advocate adding a lateral closing wedge calcaneal osteotomy (Dwyer type procedure) if the patient has a cavus or varus deformity of the hindfoot. Coughlin recommend tenodesis of the peroneus longus if less than one-third of the tendon remains.53
, 54
Shin splints and dancers
Shin splint is a nonspecific term for an overuse syndrome affecting the lower leg. Poorly conditioned and new dancers are especially susceptible to this syndrome. Usually, shin splint pain is found on the inside edge of the lower two-thirds of the tibia. This syndrome is commonly attributed to overuse of the posterior tibialis tendon and/or anterior tibial tendon. Other conditions that can elicit pain on the shin area are stress fractures and compartment syndrome.
Treatment of tibial stress fractures in elite dancers includes rest and activity modification. Miyamoto and colleagues
55
evaluated 1757 dancers; 24 dancers (1.4%) had 31 tibial stress fractures. The mean age at the time of stress fracture was 22.6 years. The mean duration of symptoms was 25.8 months.Typically, a change in activity and appropriate training along with a posterior muscle group stretching routine are sufficient to resolve shin splint problems. Rarely, as evidenced in Miyamoto and colleagues report, do the dancers require surgical intervention.
Fractures and dancers
Fractures in the dance population are common. Radiography, CT, MRI, and bone scan should be used as necessary to arrive at the correct diagnosis after a thorough physical examination. Treatment must address the fracture itself and any surrounding problems such as nutritional/hormonal issues and training/performance techniques and regimens. Compliance issues in dancers are of great concern, and treatment strategies must be developed accordingly. Stress fractures, in particular, can present difficulties for the patient and the physician.
Training concerns and age
The initiation of pointe training for dance students should be determined after careful evaluation. Evaluation of the following criteria is imperative: student’s stage of physical development; the quality of trunk, abdominal, and pelvic control (core stability); the biomechanical alignment and strength/stability of the hip, knee, ankle, and foot; and the duration and frequency of dance training. Pointe work should not be considered before the fourth year of training. Students with poor core stability or hypermobility of the feet and ankles require additional strengthening to allow them to safely begin pointe training. Students with insufficient ankle and foot plantar flexion or poor lower extremity alignment should not be allowed to do pointe because it is not worth the risk.
56
, 57
, 58
Summary
Treatment of dancers can be challenging and rewarding. Dancers often have unusual difficulties related to the dynamic biomechanical forces required by their individual dance form. A thorough understanding of these movements guides the physician to the cause of the injury, particularly in understanding specific overuse injuries. This knowledge, coupled with a meticulous physical examination, is essential for diagnosis and treatment of the dancer, who is both an artist and an athlete. Treatment requires the physician to be creative in some respects to treat the underlying biomechanical issues within the restraints of the particular dance type and shoe gear required.
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