0198-0211/91/1106-0404$03.00/0 FOOT8 ANKLE Copyright 0 1991 by the American Orthopaedic Foot and Ankle Society, Inc.
0 s Trigonum Syndrome: A Clinical Entity in Ballet Dancers Torsten Wredmark, M.D, Ph.D,. Carl A. Carlstedt, M.D., Ph.D.,t Henrik Bauer, M.D., Ph.D.,* and Tonu Saartok, M.D., Dr. Med. Sci. Huddinge and Stockholm, Sweden
players, the presence of an 0s trigonum can cause clinical symptoms requiring medical i n t e r ~ e n t i o n . ~ ~ ~ ~ ’ ~ ~ The aim of this study was to report on the results of surgical treatment of the 0s trigonum syndrome in professional ballet dancers.
ABSTRACT Thirteen Swedish National classic ballet dancers were surgically treated for an “0s trigonum syndrome.” Their main symptom was an impingement pain in the hind foot while actively plantarflexing the ankle during ballet dancing. The surgical procedure included excision of an 0s trigonum or a prominent lateral posterior process of the talus, together with division of the flexor hallucis tendon sheath if it was thickened. This procedure was safe and resulted in return of the dancers to the same level of ballet dancing within 5 to 10 weeks.
PATIENTS AND METHODS Patients
The patients were dancers at the Royal Swedish Ballet Academy and the Swedish National Ballet School. There were nine females and four males with a mean age at surgery of 20 years (range 14-31 years). The dancers had experienced progressive pain and soreness behind the medial malleolus of the ankle at dancing. No dancers had a history of acute trauma to the involved ankle. The onset of the symptoms was gradual and a ballet doctor was consulted after 1 to 8 weeks. In all cases, the initial treatment was symptomatic and consisted of physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDs). Local steroid injections were not used. However, the symptoms of the dancers prevailed despite this regimen which was given for at least 2 months. Preoperative radiographs revealed either an 0s trigonum or a prominent lateral posterior process of the talus in all patients. Eight patients had problems in the right foot, and four had problems in the left foot. One (female) had bilateral problems and was operated on both sides.
INTRODUCTION
Classical ballet dancers are frequently standing on the tips of their toes at the end of the “demi-pointe” or “en pointe” position, following repeated and forceful plantarflexion of the foot. The symptoms of posterior impingement pain in the ankle can be due to a posterior bony block of an 0s trigonum or a prominent lateral posterior process of the t a l u ~ . ~If the ~ ~onset ~ ~ , is’ ~ acute with forceful plantarflexion and pronation, the result can be a fracture.2~6~’0~’2 Repeated plantarflexion can also cause an impingement of the posterior soft tissue structures of the ankle between the calcaneus and posterior portion of the tibia.4,10i14 Moreover, repeated plantarflexion can cause an inflammatory tenovaginitis and, hence, thickening of the tendon sheath of the flexor hallucis longus (FHL) tendon4~l4 0 s trigonum is an accessory bone found in about one of 10 ankles, commonly unilateral, and normally causing no ~ y m p t o m s . ’ ~However, ~.~ in people with specific physical activity involving forceful plantarflexion, like ballet dancers, javelin throwers, or soccer
Examination
At the preoperative clinical examination, the joint laxity of the thumb, the elbow, and the knee was recorded. These signs of general joint laxity could not be confirmed in any case. Active or passive flexion of the FHL tendon revealed no local crepitation behind the medial malleolus. Additionally, passive plantarflexion gave a sensation of pain in the posterior ankle in only one-third of the cases. However, deep palpation in the same area elicited pain in all patients. Similarity, all dancers experienced disabling local pain in the “demi-
From the Department of Orthopaedic Surgery, Karolinska Institutet, Huddinge University Hospital, Huddinge, and *Department of Orthopaedic Surgery, Karolinska Institutet, Karolinska Hospital, Stockholm, Sweden. Address reprint requests to Torsten Wredmark, M.D., Ph.D., Department of Orthopaedic Surgery, Karolinska Institutet, Huddinge University Hospital K 54, S-141 86 Huddinge, Sweden. t deceased. 404
0s
Foot & Ankle/Vol. 11, No. 6/June 1991
pointe” or “en pointe” position, i.e., maximal active plantarflexion while standing on one foot. The loaded range of motion (ROM) in both ankles was measured clinically with the knee in 90” of flexion, as described by Lindsjo,’ which is a modification of the method of Russe and Gerhardt.13 At the postoperative examination, 22 months (mean) after surgery (range 3-54 months), the subjective outcome and level of dancing were recorded using a questionnaire. The loaded range of motion was determined as preoperatively. Mean and standard deviation (SD) was calculated for each variable measured. Student’s t-test pairs was used to compare the results of surgery. The level of significance was chosen as 0.05. SURGICAL PROCEDURE
Surgery was performed with the patient in a supine position and with a tourniquet. A medial approach was used, by means of a 5-cm vertical incision anterior to the Achilles tendon. The neurovascular bundle was identified and retracted. The tendon sheath of FHL was incised longitudinally. The 0s trigonum was identified and removed, whereas in cases with a prominent lateral posterior process of the talus, ostectomy was performed. In at least half of the cases, a thickening of the FHL tendon and/or tendon sheath was observed. The incision of the tendon sheath was then extended both proximally and distally. The wound was closed only with skin sutures. No casting was used, and the rehabilitation was started immediately after surgery and consisted of nonweight-bearing ROM exercises for 2 weeks, followed by gradual stretching and strength training. RESULTS
There were no cases of hematoma or infection postoperatively, nor any case of sensory or motor loss. All patients but one were relieved from their symptoms and could return to full performance dancing within 10 weeks after surgery (mean 7 weeks; range 5-10 weeks). At the follow-up (mean 22 months after surgery), 12 dancers were dancing at the same level, but one had stopped ballet dancing, due to the foot problem. The loaded ROM before surgery was similar in the non-injuredankle (74 f 8”;mean f SD) and the painful ankle (72 f 10”). The loaded ROM was not different between the symptomatic and normal foot in an individual, neither before (1 f lo”),nor after (4 f 8’) surgery (P > 0.05).
TRIGONUM SYNDROME
405
DISCUSSION
The problem of 0s trigonum syndrome and FHL tendinitis in ballet dancers have been recognized by several authors. Howse described that a bony block at the back of the ankle joint, e.g., the 0s trigonum or a large posterior tubercle of the talus, can interfere with d a n ~ i n gHamilton4 .~ has described the FHL tendon to be “the Achilles tendon of ballet dancer’s foot.” The most important factors in diagnosis are the local signs at the clinical examination in combination with radiographs and history. Hamilton4has stated that clinically there is often localized tenderness or crepitus on palpation behind the medial malleolus, as well as pain upon palpation of the tendon while actively or passively moving the hallux. In the present study, none of the 13 feet presented with crepitus, whereas all patients experienced pain upon deep palpation. Paulos et al.” found that patients with fracture of the 0s trigonum had a 25” decrease in plantarflexion of the injured foot compared to the other foot. However, in our study, the loaded ROM measurements’ were not different in the injured ankles as compared to the noninjured ankles in an individual, neither before nor after surgery. This can possibly be due to the fact that only the combination of FHL muscle contraction and weightbearing gives pain. Both medial and lateral approaches have been suggested for surgery of the 0s trigonum or the lateral posterior process of the Our preferred surgical approach from the medial side can be justified by the common finding of FHL tendon pathology. CONCLUSIONS
In summary, this study shows that progressive symptoms of pain in the posterior area of the ankle in ballet dancers can be due to an 0s trigonum syndrome, and that this can be successfully treated with surgery. The excision of an 0s trigonum or a lateral posterior process of the talus does not seem to hamper high performance activity such as classical ballet dancing. To the contrary, the recovery period was short and most patients were fully active within 2 months. The reason for the single unsuccessful case is not clear, but could be due to an insufficient division of the FHL tendon sheath. Apparently, the diagnosis of 0s trigonum syndrome has to be suspected to a higher degree in patients with specific physical activity, e.g., ballet dancers and soccer player^.^,^,' The proposed treatment, including both an excision of aberrant bone and release of the FHL tendon sheath, seems to be safe and leads to immediate relief and quick return to high level activity. 431
406
WREDMARK ET AL.
REFERENCES 1. Burman, M., and Lapidus, P.: The functional disturbances caused by the inconstant bones and sesamoids of the feet. Arch. Surg., 22:936-975, 1931. 2. Ecker, M., and Rilter, M.: The symptomatic 0s trigonum. J.A.M.A., 201:204-206, 1967. 3. Geist, E.: Supernumerary bones of the feet-a roentgen study of the feet of 100 normal individuals. Am. J. Orthop. Surg., 12B3403-414, 1914. 4. Hamilton, W.: Stenosing tenosynovitis of the flexor hallucis longus tendon and posterior impingement upon the 0s trigonum in ballet dancers. Foot Ankle, 3:74-80, 1982. 5. Howse, A.J.G.: Posterior block of the ankle joint in dancers. Foot Ankle, 3:81-84, 1983. 6. Ihle, C.L., and Cochran, R.M.: Fracture of the fused 0 s trigonum. Am. J. Sports Med., 10:47-50,1982. 7. Kravitz S.R.:The mechanics of dance and dance-relatedinjuries. In Sports Medicine of the Lower Extremity. Subotnic S.A. (ed.), Churchill Livingstone, New York, 1989, pp. 595-603.
Foot & Ankle/Vol. 11, No. 6/June 1991 8. Lindsjo, U.: Operativetreatment of ankle fractures. Acta Orthop. Scand., 52 (Suppl. 189):131, 1981. 9. McDougall, A.: The 0 s trigonum. J. Bone Joint Surg., 37B257265,1965. 10. Moeller, F.A.: The 0 s trigonum syndrome. J. Am. Podiatr. AsSOC., 63~491-501,1973. 11. Paulos, L.E., Johnson C.L., and Noyes F.R.: Posterior compartment fractures of the ankle. Am. J. Sports Med., 11:439443,1983. 12. Quirk, R.: Talar compression syndrome in dancers. Foot Ankle, 3~65-68, 1982. 13. Russe O.A., and Gerhardt J.J.: International SFTR method of measuringand recordingjoint motion. ISOM InternationalStandard Orthopaedic Measurement. Bern, Hans Huber Publ., 1975. 14. Sammarco, G.J.: The foot and ankle in dancers. In The Foot. Helal B., Wilsson D. (eds.), Edinburgh, Churchill- Livingstone, 1988, pp. 1007-1 032. 15. Wessmark, 0.: The 0s trigonum syndrome in javelin throwers and soccer players. Abstract (in Swedish), Annual Meeting of the Swedish Society of Sports Medicine, Orebro, Sweden, 1989.
0 s Trigonum Syndrome: A Clinical Entity in Ballet Dancers Torsten Wredmark, M.D, Ph.D,. Carl A. Carlstedt, M.D., Ph.D.,t Henrik Bauer, M.D., Ph.D.,* and Tonu Saartok, M.D., Dr. Med. Sci. Huddinge and Stockholm, Sweden
players, the presence of an 0s trigonum can cause clinical symptoms requiring medical i n t e r ~ e n t i o n . ~ ~ ~ ~ ’ ~ ~ The aim of this study was to report on the results of surgical treatment of the 0s trigonum syndrome in professional ballet dancers.
ABSTRACT Thirteen Swedish National classic ballet dancers were surgically treated for an “0s trigonum syndrome.” Their main symptom was an impingement pain in the hind foot while actively plantarflexing the ankle during ballet dancing. The surgical procedure included excision of an 0s trigonum or a prominent lateral posterior process of the talus, together with division of the flexor hallucis tendon sheath if it was thickened. This procedure was safe and resulted in return of the dancers to the same level of ballet dancing within 5 to 10 weeks.
PATIENTS AND METHODS Patients
The patients were dancers at the Royal Swedish Ballet Academy and the Swedish National Ballet School. There were nine females and four males with a mean age at surgery of 20 years (range 14-31 years). The dancers had experienced progressive pain and soreness behind the medial malleolus of the ankle at dancing. No dancers had a history of acute trauma to the involved ankle. The onset of the symptoms was gradual and a ballet doctor was consulted after 1 to 8 weeks. In all cases, the initial treatment was symptomatic and consisted of physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDs). Local steroid injections were not used. However, the symptoms of the dancers prevailed despite this regimen which was given for at least 2 months. Preoperative radiographs revealed either an 0s trigonum or a prominent lateral posterior process of the talus in all patients. Eight patients had problems in the right foot, and four had problems in the left foot. One (female) had bilateral problems and was operated on both sides.
INTRODUCTION
Classical ballet dancers are frequently standing on the tips of their toes at the end of the “demi-pointe” or “en pointe” position, following repeated and forceful plantarflexion of the foot. The symptoms of posterior impingement pain in the ankle can be due to a posterior bony block of an 0s trigonum or a prominent lateral posterior process of the t a l u ~ . ~If the ~ ~onset ~ ~ , is’ ~ acute with forceful plantarflexion and pronation, the result can be a fracture.2~6~’0~’2 Repeated plantarflexion can also cause an impingement of the posterior soft tissue structures of the ankle between the calcaneus and posterior portion of the tibia.4,10i14 Moreover, repeated plantarflexion can cause an inflammatory tenovaginitis and, hence, thickening of the tendon sheath of the flexor hallucis longus (FHL) tendon4~l4 0 s trigonum is an accessory bone found in about one of 10 ankles, commonly unilateral, and normally causing no ~ y m p t o m s . ’ ~However, ~.~ in people with specific physical activity involving forceful plantarflexion, like ballet dancers, javelin throwers, or soccer
Examination
At the preoperative clinical examination, the joint laxity of the thumb, the elbow, and the knee was recorded. These signs of general joint laxity could not be confirmed in any case. Active or passive flexion of the FHL tendon revealed no local crepitation behind the medial malleolus. Additionally, passive plantarflexion gave a sensation of pain in the posterior ankle in only one-third of the cases. However, deep palpation in the same area elicited pain in all patients. Similarity, all dancers experienced disabling local pain in the “demi-
From the Department of Orthopaedic Surgery, Karolinska Institutet, Huddinge University Hospital, Huddinge, and *Department of Orthopaedic Surgery, Karolinska Institutet, Karolinska Hospital, Stockholm, Sweden. Address reprint requests to Torsten Wredmark, M.D., Ph.D., Department of Orthopaedic Surgery, Karolinska Institutet, Huddinge University Hospital K 54, S-141 86 Huddinge, Sweden. t deceased. 404
0s
Foot & Ankle/Vol. 11, No. 6/June 1991
pointe” or “en pointe” position, i.e., maximal active plantarflexion while standing on one foot. The loaded range of motion (ROM) in both ankles was measured clinically with the knee in 90” of flexion, as described by Lindsjo,’ which is a modification of the method of Russe and Gerhardt.13 At the postoperative examination, 22 months (mean) after surgery (range 3-54 months), the subjective outcome and level of dancing were recorded using a questionnaire. The loaded range of motion was determined as preoperatively. Mean and standard deviation (SD) was calculated for each variable measured. Student’s t-test pairs was used to compare the results of surgery. The level of significance was chosen as 0.05. SURGICAL PROCEDURE
Surgery was performed with the patient in a supine position and with a tourniquet. A medial approach was used, by means of a 5-cm vertical incision anterior to the Achilles tendon. The neurovascular bundle was identified and retracted. The tendon sheath of FHL was incised longitudinally. The 0s trigonum was identified and removed, whereas in cases with a prominent lateral posterior process of the talus, ostectomy was performed. In at least half of the cases, a thickening of the FHL tendon and/or tendon sheath was observed. The incision of the tendon sheath was then extended both proximally and distally. The wound was closed only with skin sutures. No casting was used, and the rehabilitation was started immediately after surgery and consisted of nonweight-bearing ROM exercises for 2 weeks, followed by gradual stretching and strength training. RESULTS
There were no cases of hematoma or infection postoperatively, nor any case of sensory or motor loss. All patients but one were relieved from their symptoms and could return to full performance dancing within 10 weeks after surgery (mean 7 weeks; range 5-10 weeks). At the follow-up (mean 22 months after surgery), 12 dancers were dancing at the same level, but one had stopped ballet dancing, due to the foot problem. The loaded ROM before surgery was similar in the non-injuredankle (74 f 8”;mean f SD) and the painful ankle (72 f 10”). The loaded ROM was not different between the symptomatic and normal foot in an individual, neither before (1 f lo”),nor after (4 f 8’) surgery (P > 0.05).
TRIGONUM SYNDROME
405
DISCUSSION
The problem of 0s trigonum syndrome and FHL tendinitis in ballet dancers have been recognized by several authors. Howse described that a bony block at the back of the ankle joint, e.g., the 0s trigonum or a large posterior tubercle of the talus, can interfere with d a n ~ i n gHamilton4 .~ has described the FHL tendon to be “the Achilles tendon of ballet dancer’s foot.” The most important factors in diagnosis are the local signs at the clinical examination in combination with radiographs and history. Hamilton4has stated that clinically there is often localized tenderness or crepitus on palpation behind the medial malleolus, as well as pain upon palpation of the tendon while actively or passively moving the hallux. In the present study, none of the 13 feet presented with crepitus, whereas all patients experienced pain upon deep palpation. Paulos et al.” found that patients with fracture of the 0s trigonum had a 25” decrease in plantarflexion of the injured foot compared to the other foot. However, in our study, the loaded ROM measurements’ were not different in the injured ankles as compared to the noninjured ankles in an individual, neither before nor after surgery. This can possibly be due to the fact that only the combination of FHL muscle contraction and weightbearing gives pain. Both medial and lateral approaches have been suggested for surgery of the 0s trigonum or the lateral posterior process of the Our preferred surgical approach from the medial side can be justified by the common finding of FHL tendon pathology. CONCLUSIONS
In summary, this study shows that progressive symptoms of pain in the posterior area of the ankle in ballet dancers can be due to an 0s trigonum syndrome, and that this can be successfully treated with surgery. The excision of an 0s trigonum or a lateral posterior process of the talus does not seem to hamper high performance activity such as classical ballet dancing. To the contrary, the recovery period was short and most patients were fully active within 2 months. The reason for the single unsuccessful case is not clear, but could be due to an insufficient division of the FHL tendon sheath. Apparently, the diagnosis of 0s trigonum syndrome has to be suspected to a higher degree in patients with specific physical activity, e.g., ballet dancers and soccer player^.^,^,' The proposed treatment, including both an excision of aberrant bone and release of the FHL tendon sheath, seems to be safe and leads to immediate relief and quick return to high level activity. 431
406
WREDMARK ET AL.
REFERENCES 1. Burman, M., and Lapidus, P.: The functional disturbances caused by the inconstant bones and sesamoids of the feet. Arch. Surg., 22:936-975, 1931. 2. Ecker, M., and Rilter, M.: The symptomatic 0s trigonum. J.A.M.A., 201:204-206, 1967. 3. Geist, E.: Supernumerary bones of the feet-a roentgen study of the feet of 100 normal individuals. Am. J. Orthop. Surg., 12B3403-414, 1914. 4. Hamilton, W.: Stenosing tenosynovitis of the flexor hallucis longus tendon and posterior impingement upon the 0s trigonum in ballet dancers. Foot Ankle, 3:74-80, 1982. 5. Howse, A.J.G.: Posterior block of the ankle joint in dancers. Foot Ankle, 3:81-84, 1983. 6. Ihle, C.L., and Cochran, R.M.: Fracture of the fused 0 s trigonum. Am. J. Sports Med., 10:47-50,1982. 7. Kravitz S.R.:The mechanics of dance and dance-relatedinjuries. In Sports Medicine of the Lower Extremity. Subotnic S.A. (ed.), Churchill Livingstone, New York, 1989, pp. 595-603.
Foot & Ankle/Vol. 11, No. 6/June 1991 8. Lindsjo, U.: Operativetreatment of ankle fractures. Acta Orthop. Scand., 52 (Suppl. 189):131, 1981. 9. McDougall, A.: The 0 s trigonum. J. Bone Joint Surg., 37B257265,1965. 10. Moeller, F.A.: The 0 s trigonum syndrome. J. Am. Podiatr. AsSOC., 63~491-501,1973. 11. Paulos, L.E., Johnson C.L., and Noyes F.R.: Posterior compartment fractures of the ankle. Am. J. Sports Med., 11:439443,1983. 12. Quirk, R.: Talar compression syndrome in dancers. Foot Ankle, 3~65-68, 1982. 13. Russe O.A., and Gerhardt J.J.: International SFTR method of measuringand recordingjoint motion. ISOM InternationalStandard Orthopaedic Measurement. Bern, Hans Huber Publ., 1975. 14. Sammarco, G.J.: The foot and ankle in dancers. In The Foot. Helal B., Wilsson D. (eds.), Edinburgh, Churchill- Livingstone, 1988, pp. 1007-1 032. 15. Wessmark, 0.: The 0s trigonum syndrome in javelin throwers and soccer players. Abstract (in Swedish), Annual Meeting of the Swedish Society of Sports Medicine, Orebro, Sweden, 1989.
