Presentation, treatment, and outcome of tarsal coalitions in dancers: a retrospective case series.
Restricted subtalar motion, as revealed by the (modified) heel tip test, (6,7) is suggestive of the diagnosis. In this test, the patient is observed while forcing his or her feet into supination (inversion) in a standing position (Fig. 1).
A decrease in hindfoot motion is a sign of restricted subtalar motion. The hindfoot motion is the total of inversion and eversion in the foot and can be quantified by measuring the calcaneal angle (Fig. 2). (4,8)
Another sign demonstrated on physical examination is a rigid pes planus, or flatfoot. This can be examined using the "Hubscher maneuver," or "Jack Test." (9,10) The test is performed with the patient weightbearing while the clinician dorsiflexes the hallux and watches for restoration of the normal arch of the foot (Fig. 3). A positive assessment results from the flatfoot being flexible (arch formation); a negative assessment results from the flatfoot being rigid or contracted (lack of arch formation). (6,11)
In the general population, conservative treatment for symptomatic tarsal coalition aims to reduce stress on the tarsus or midfoot (12) by reducing activities that provoke symptoms or supporting the foot with orthoses. (5,13) Operative treatment options depend on the type of coalition. According to the literature, a calcaneo-navicular coalition can be treated successfully by resection of the coalition. (12,14) In talo-calcaneal coalitions, resection has inconsistent results, and the most commonly used surgical treatment is a triple or subtalar arthrodesis. (5,12,13,15,16)
The prevalence and optimal therapy of tarsal coalition in dancers are both unknown. The purpose of this article is to increase awareness by describing the presentation, types, and possible treatment modalities of tarsal coalitions in dancers.
Retrospectively, all consecutive patients at our institution who had been diagnosed clinically with a tarsal coalition that had been confirmed by computed tomography (CT) that had been evaluated by a musculoskeletal radiologist between 2008 and 2011 were identified. Any dancer or dance student dancing for at least 3 to 5 hours per week was included. Because of low incidence, all patient information was registered in a simple notebook and collected by the first author.
Ethics approval for this retrospective case series was obtained from the Medisch Ethische Toetsingscommissie Zuidwest Holland (METC-nr: 10025). Data on presentation and treatment were extracted from the medical records. Patients gave informed consent to participate in the study. For the end result, the dancers were interviewed regarding their perceived satisfaction and ability to participate in their desired dance activities 6 to 36 months after the completion of treatment.
A 10-year-old female recreational dancer (classical, contemporary, jazz, and tap) who danced 4 hours per week, experienced pain in the instep of her right foot and repeatedly sprained her right ankle, which limited her dancing. Physical examination elsewhere revealed a rigid subtalar joint. Lateral and antero-posterior radiographs of the feet showed no abnormalities. A CT scan of the right ankle showed fibrous tissue between the calcaneus and the navicular. An oblique (3/4) radiograph also showed the calcaneonavicular coalition in the right foot only (Fig. 4).
A resection of the "bar" in the right foot with interposition of the extensor digitorum brevis was performed in a different clinic. After two weeks in a circular lower leg cast, she started non-weightbearing functional mobilization. Thereafter she came to our clinic and began a dance-specific rehabilitation program. (17) The schedule was graded, with progression from no-, to low-, to high-impact exercises, but was also coordinated with activities in dance class. At three and six months after surgery she had no limitations and was able to participate fully in her dance classes and increase her dance activity to 7 hours per week. A postoperative radiograph clearly showed the resection of the "bar" (Fig. 4C). At 1 year postoperatively, she was dancing without limitation for 5 to 7 hours per week. At two years postoperatively, she was still dancing 7 hours per week, had almost symmetrical subtalar mobility, but mild lateral discomfort due to minor degenerative changes in the calcaneo-cuboid joint, which have been successfully treated with orthotics.
A tarsal coalition had been diagnosed during a physical screening required for admission to a vocational dance education program in a 13-year-old male recreational dancer (dancing 5.5 hours per week) and hockey player who was anticipating a career as a break dancer. For 4 months he had been experiencing pain under the lateral malleolus of his right foot during physical exercise, more while playing hockey than when dancing. No trauma had occurred. Physical examination showed a rigid pes planovalgus on the right side and that hindfoot motion was diminished. Active dorsiflexion of the talocrural joint of both feet was equal, but passive dorsiflexion of the right foot was painful. The strength of the posterior tibial muscle of the right foot was insufficient. This was tested in maximum active plantar flexion of the talocrural joint (i.e., "pointing" or "tendu") and by having the patient invert and adduct his foot. The strength is considered to be insufficient if the patient is not able to overcome full resistance of the examiner. Plain radiographs and a CT showed a calcaneo-navicular coalition of the right foot that was beginning to ossify.
A resection of the "bar" in the right foot was performed. The edges were covered with bone wax, and "spongostan" (an absorbable hemostatic gelatin sponge) was placed between the bone edges to prevent fusion. Preoperatively, exercises were given to strengthen the peroneal and tibialis posterior muscles. Postoperatively the patient was non-weightbearing for 3 weeks. Two months postoperatively, the peroneal muscles on the operated right side were still insufficient, and he was unable to participate fully in dance activities. A dance-specific rehabilitation program, including strengthening exercises for the peroneal muscles, was started. Within six months after surgery, he was able to participate fully in dance activities.
A presumably symptom free 16-yearold female dancer was found to have a rigid subtalar joint in both feet, more obviously on the right, during pre-vocational screening. Confronted with these findings, the patient realized that she always felt unstable on uneven surfaces and that she avoided these circumstances to prevent ankle sprains on the right, and that she also experienced some stiffness in her right ankle. The mobility in the right talocrural joint was limited; her tendu (active plantar flexion of the foot-ankle complex, a.k.a. "pointing") was a full 90[degrees] (dorsum of foot in line with front of tibia) on the left side and 85[degrees] (which means "limited" for a dancer) on the right. There was full strength of 0.3 for the tibialis posterior and peroneal muscle groups bilaterally. Radiographs showed a fibrocartilaginous calcaneo-navicular coalition in both feet, more clearly on the right side (Fig. 5). This was confirmed with a CT scan.
Initially, after extensive explanation, the advice was given to start a dance-education program and not "save" the feet during dance training; i.e., to dance fully. Immediately after starting the program, she experienced little pain, but found herself too limited in her dancing abilities due to stiffness of her feet, especially the right foot, in jumps and tendus. Gradually she started to experience pain and became convinced that an operation was unavoidable. Half a year after the start of her vocational dance training, the coalition or "bar" in the right foot was resected at age 17. She resumed her dance training at a professional level 6 months after the operation, and 1.5 years after the resection the patient subjectively reported an excellent result (Fig. 5C-F).
An 11-year-old female recreational dancer anticipating a professional career as a musical show dancer presented to our clinic. She danced approximately 10 hours per week and also trained in gymnastics for 3 hours a week. On initial presentation she was pain free and had rigid flat feet, particularly on the left side. She mentioned that she had often received comments from her dance teachers on the shape and position of her feet. Physical examination showed a rigid pes planovalgus and subtalar joint on the left side. The medial foot border did not improve in releve (Fig. 6).
Radiographs (antero-posterior and oblique) of the left tarsus showed no abnormalities, but the talo-calcaneal joint could not be properly assessed. A CT showed a fibrous talo-calcaneal coalition in the left foot in which at least 30% of the joint surface was involved. The whole middle facet of the talocalcaneal joint was involved (Fig. 7A). At the age of 13.5 years, another CT showed that the coalition had almost completely ossified (Fig. 7B).
Because this patient had a pain free talo-calcaneal coalition with involvement of a large percentage of the joint surface in a weightbearing part of the joint, a regimen of observation and conservative treatment was chosen. She received a custom-made night splint and an UCBL orthosis, (18) an insole constructed from a plaster mold taken while the foot is in its neutral position ("casted in situ"), in an attempt to prevent further (valgus) deformity (Fig. 8) and to support the foot in her ordinary street shoes. During follow-up, it was noticed that there was obvious wasting of the calf, weakness of the left m. tibialis posterior, and insufficient strength in the peroneal muscles bilaterally. Specific exercises were given to strengthen these muscles. After a period of 6 months, full strength and muscle balance were achieved, and she experienced no limitations in the activities of daily living or in dancing.
At follow-up, she did complain of pain with releve and tendus. Upon examination, there was tenderness of the tendon of the m. flexor hallucis longus (FHL) in the left foot. A typical FHL tendovaginitis, common in dancers, was diagnosed. It was believed that the valgus position of the foot may have triggered this "dancers' tendinitis," and at age 13.5, an operative release of the FHL tendon sheath was performed. After 6 weeks, the patient subjectively reported a good result, and with the dance-specific rehabilitation program, (17) she built up her dancing. One year after the FHL release on the left side she was able to participate fully in all dance activities, including classical ballet. She currently is training at a professional level in a vocational musical show dance academy.
A 26-year-old ballroom dancer presented to our clinic for a second opinion about her ankle complaints. She had experienced multiple sprains of the left ankle. After a period of intensive training, without specific trauma, she noticed increasing pain deep in the ankle, under the lateral malleolus. She had been treated with taping and had a thorough analysis where it was found that "there is something wrong" in the subtalar joint, for which she wore a cast for 4 weeks. Her lower leg then became edematous and red, so the cast was removed. After this, on first examination in our clinic, there was a rigid left subtalar joint and weakness of the peroneal muscles. Review of an earlier MRI showed an overlooked talo-calcaneal coalition with a large percentage of the joint surface involved. A CT scan revealed the coalition to be more clearly visible (Fig. 9).
A removable circular walking cast was provided, and she was advised to mobilize the ankle and foot in a swimming pool. This combination of immobilization and mobilization relieved some of the pain, but the foot was still painful. To help relieve the pain, an UCBL orthosis was provided and the patient was advised to stay fit with no-impact cardio-exercises, for instance bike riding. Due to the pain in her foot, she stopped dancing completely. She was able to cope with the discomfort in daily life, having a sedentary occupation, and for this reason chose not to undergo an operative procedure.
A 21-year-old female professional dancer in an Asian ballet company visited our institution for a second opinion. She had instability and pain on the anterolateral side of the left ankle. There were problems with plantar flexion when dancing on pointe. As a result of the pain, her ability to perform was severely reduced, and she had to apply for Workers Compensation. She was, however, able to rehearse and had been teaching. Physical examination of the left ankle revealed limited inversion, a rigid subtalar joint, and weakness of the left peroneal muscles. There was full strength of the tibialis posterior muscles bilaterally. Radiographs of the foot, including in releve, showed no abnormalities. At this point, no diagnosis was made. One and a half years later, a CT of the left ankle showed a large talo-calcaneal coalition (synostosis). There was complete coalescence (bony fusion) between the sustentaculum tali and the calcaneus (Fig. 10). In retrospect, the radiographs of the left foot in releve showed a so-called C-sign (Fig. 11). This is caused by fusion of the inferomedial border of the talus with the sustentaculum tali. (1,5,19)
Using a dance-specific graded rehabilitation program (17) as well as specific strengthening of the peroneal and calf muscles, she was able to dance again and perform in Swan Lake on pointe. Due to the lack of compensatory movement in the subtalar joint, she will have to be careful in situations of stress, fatigue, and especially on rough, uneven surfaces or raked stages. However, due to the high demands of dancing as a soloist in a professional ballet company, and given the recurrent limitations of her left foot, she decided to terminate her performing career and now continues as a dance teacher.
A 16-year-old female ballet student in the last year of her vocational dance education presented with a bony lump in the tarsal tunnel behind the medial malleolus, producing slight discomfort, in spite of which she was able to dance fully for over 30 hours per week, including heavy pointe work. She had insufficient strength in the peroneals, and for a classical ballerina she had normal hypermobile talo-crural joint mobility. Sonography confirmed the lump to be bony in origin. On CT it was diagnosed to be the bony prominence of a talo-calcaneal bar, a diagnosis that had been initially missed clinically. On repeated physical examination, knowing the diagnosis, the heel tip test revealed a mildly limited subtalar motion.
She was treated conservatively, including extensive explanation of the condition, strengthening exercises for the peroneal muscles, and custom made UCBL orthotics for her street shoes. Ten months after initial presentation she was able to continue her dancing career, understanding well the delicate condition of her foot.
In general, the prime concern in the treatment of dancers is to safeguard the ability to pursue a career in dance, which is both their living and their passion.
We are aware of only one previous report on tarsal coalition in a dancer. (20) With permission of the author we contacted this patient and discovered that she dances only incidentally and recreationally, by far failing to meet our inclusion criterion of at least 3 to 5 hours per week.
Cohort studies have not been described.
We recognize several limitations of this study: expert recall, small numbers, retrospective and nonstandardized measurement methods (we did not use a specific standardized survey tool or postoperative treatment protocol), which makes it difficult to compare our patients scientifically. However, our purpose is simply to describe qualitatively the presentation, treatment, and outcome of seven consecutive dancers with tarsal coalitions in order to increase awareness of this rare condition.
Within the time frame of this study, we may have seen 1,000 to 1,500 dancers in total, so the prevalence of tarsal coalition in the dance population visiting our center is approximately 0.5% to 1%, which is slightly lower than in the general population (1% to 3%).
In spite of its rarity, it is hard to believe that in the physically demanding activity of professional dance a tarsal coalition could exist and remain overlooked for any period of time, especially in dancers dancing on pointe.
A pain free foot deformity like hyperpronation, recurrent ankle sprains, or a stiff subtalar joint, especially in adolescent dance students, should raise clinical suspicion and justify referral to an orthopaedic surgeon for further analysis. We recommend that the heel tip test should be part of any dance screening.
After history taking and physical examination, the next step in diagnosis is to take plain film x-rays: AP and oblique views of the subtalar joint. In our center, x-rays on releve are part of the protocol for all our dancer patients. This may be followed by CT or MRI, depending on availability and personal preference. We prefer CT, as this more clearly shows the bony configuration, and we believe MRI may lead to over diagnosis.
Since six of the seven patients in this study did have insufficient strength of the peroneal muscles, we recommend strengthening exercises for these muscles. We consider applying UCBL orthoses, in neutral position of the feet ("casted in situ"), to be another important step in conservative treatment, aiming to prevent further (valgus) deformity of the feet.
Six of these seven dancers were able to continue their careers in dance after resection or conservative treatment (including one, case 6, who did not return to her previous level of activity but continued as a dance teacher). We consider this a good result.
The results of treatment in dancers seem to match the recommendations found in the literature for non-dancers. The three dancers with a calcaneonavicular bar improved after operative treatment with early resection of the bar, although one of them had mild residual complaints. However, according to the literature on non-dancers with talo-calcaneal bars, a conservative approach is preferred because in these cases resection will lead to degeneration or an unintended fusion of the resected part of the subtalar joint, which is hard to avoid since the talo-calcaneal_joint is a weight-transferring joint. (2,5,12,13,15,16) Arthrodesis results in a rigid subtalar joint, which may not be compatible with the high demands of a dancer.
In the only dancer who had to stop dancing (case 5) the talo-calcaneal coalition was diagnosed as late as at age 26. She might have pursued her dancing career longer and with fewer complaints if she had been aware of this condition earlier and her recurrent sprains had been prevented by adequate conservative treatment.
Conclusion and Recommendations
When a dancer is found to have decreased subtalar mobility with or without ankle pain, a rigid flatfoot (hyperpronation), or recurrent ankle sprains, clinicians should consider the possibility of a tarsal coalition in their differential diagnosis. Early diagnosis provides more treatment options and vocational choices. The decision for conservative or operative treatment in dancers depends on age, severity of complaints, and the type and extent of the tarsal coalition. In calcaneo-navicular coalition, early resection of the "bar" is anticipated. In talo-calcaneal coalition we consider the treatment of choice to be conservative.
The condition justifies a thorough analysis; it may limit but does not necessarily mean the immediate end of a career in dance.
To obtain further knowledge of the prevalence, incidence, and results of treatment of tarsal coalition in dancers, a larger multicenter cohort study is needed. In view of its rarity, international collaboration may be required.
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A. B. M. Rietveld, M.D., B.A.(mus.), and A. E. van Loon-Felter, M.D., Medical Centre for Dancers & Musicians, The Hague Medical Centre (HMC), The Hague, The Netherlands.
Correspondence: A. B. M. (Boni) Rietveld M.D., B.A.(mus.), Boekenroodeweg 24, NL 2111 HN Aerdenhout, The Netherlands; firstname.lastname@example.org.
Caption: Figure 1 Examples of the modified heel tip test in two patients with a tarsal coalition. A, Patient 4: In the left extremity supination (inversion) of the foot and normal external rotation of the tibia are absent. B, Patient 5: Shows a more subtle situation; in the affected left foot supination is limited.
Caption: Figure 2 Patient 4. Measurement of total hindfoot motion using the calcaneal angle (dorsal view). In this example, right foot total hindfoot motion is 24[degrees] and in the coalesced left foot only 10[degrees]. A, Left foot, 0[degrees] inversion; B, Right foot, 12[degrees] inversion; C, Left foot, 10[degrees] eversion; D, Right foot, 12[degrees] eversion.
Caption: Figure 3 "Hubscher maneuver" or "Jack Test" to check for flexibility of hyperpronation. A, Normal weightbearing stance with mild hyperpronation. B, Lifting the hallux corrects hyperpronation.
Caption: Figure 4 Patient 1. A, Oblique (3/4) radiograph preoperatively of a fibrocartilaginous calcaneo-navicular coalition in the right foot. B, Oblique (3/4) radiograph of normal left foot in the same patient. C, Oblique (3/4) radiograph postoperatively after resection of the calcaneo-navicular bar in the right foot.
Caption: Figure 5 Patient 3. Calcaneo-navicular coalition. A, B, and C, Right foot AP view preoperatively and at 2 weeks and 18 months postoperatively (fixation button for suture of interposed m. extensor digitorum brevis clearly visible on medial side (B). D, E, and F, Right foot oblique view preoperatively and at 2 weeks and 18 months postoperatively.
Caption: Figure 6 Patient 4. Medial foot border does not improve in releve in the left coalesced foot.
Caption: Figure 7 A, Patient 4. Coronary (frontal) CT showing on the left a normal talo-calcaneal relation in the right foot and on the right a fibrous talo-calcaneal coalition in the left foot. B, Same patient two years later; talo-calcaneal coalition in the left foot has ossified.
Caption: Figure 8 Patient 4. UCBL orthosis to support the foot, and prevent further (valgus) deformity. A, Lateral view of hyperpronated left foot and UCBL-orthosis. B, Frontal view of same foot and orthosis.
Caption: Figure 9 Patient 5. CT scan showing a talo-calcaneal coalition.
Caption: Figure 10 Patient 6. CT scans of the ankle and subtalar joint showing a synostosis between the talus and the calcaneus. A, Coronary CT view. B, Lateral CT view.
Caption: Figure 11 Patient 6. Plain radiographs "on releve." In talo-calcaneal coalition, a "Csign" can be seen (B), caused by fusion of the inferomedial border of the talus with the sustentaculum tali of the calcaneus. A, Right, asymptomatic foot. B, In the left foot a C-sign is visible in the area of the posterior talo-calcaneal joint.
Please note: Illustration(s) are not available due to copyright restrictions.
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|Author:||Rietveld, A.B.M.; van Loon-Felter, A.E.|
|Publication:||Journal of Dance Medicine & Science|
|Date:||Oct 1, 2016|
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