Os
trigonum impingement in dancers* JOSEPH J. MAROTTA, MD, AND LYLE J. MICHELI,† MD From The Children’s
Hospital, Boston,
Massachusetts
i
This problem has variously been named the os trigonum syndrome, talar compression syndrome, posterior ankle impingement syndrome, and posterior tibiotalar impingement syndrome.1-3 Although rarely noted in the general public, it has been described in gymnasts and dancers, particularly in ballet dancers, who forcefully point the foot into an artistically desirable, straight and rigid, high-arched, shock-absorbing platform.4.5 Earlier studies have outlined the pathomechanics and clinical presentation of this syndrome.l~2 We have reviewed a series of patients treated surgically by resection of the os trigonum to determine the clinical outcome of this therapeu-
ABSTRACT Sixteen
underwent surgical excision of an imossicle pinging through a posterior lateral approach. Twelve of these patients (15 ankles) were available for followup and were retrospectively surveyed at an average of 28 months after surgery. There were 9 women and 3 men. Nine were professional ballet dancers and 3 were students of advanced ballet schools. Preoperative symptoms included pain localized to the posterior ankle, limitation of motion, weakness, swelling, or neurologic changes associated with dance activities. All patients were severely hampered in their dance participation and had failed nonsurgical therapies. Postoperatively, all patients followed an aggressive rehabilitation protocol. All had improvement in their impingement symptoms; eight (67%) still had occasional discomfort. All professional dancers returned to unrestricted dance activity. The mean time to full activity was 3 months. One patient had a superficial wound infection requiring antibiotic treatment and another suffered a transient tibial nerve neurapraxia. Both of these complications resolved without sequelae. We conclude that posterior ankle impingement in ballet dancers, caused by an os trigonum and resistant to nonsurgical therapies, is effectively treated with simple excision of the offending structure.
patients
tic intervention.
MATERIALS AND METHODS Sixteen patients who suffered from posterior ankle impingement secondary to a radiologically identifiable os trigonum underwent resection of the ossicle when conservative measures failed to resolve symptoms. The procedures were performed between March 1984 and November 1989. Four patients were lost to followup, leaving 12 patients (15 ankles) who were contacted and surveyed. They were asked about their pre- and postoperative function, activity limitations, symptoms, prior treatment modalities, rehabilitation course, time to full participation, and ongoing treatments or problems. All procedures were performed under the direction of one
of posterior ankle pain are relatively common in ballet dancers. The differential diagnosis of this complaint includes tendinitis, capsulitis, and mechanical impingement of the posterior elements of the talus between the posterior tibia and calcaneus. In a relatively high proportion of these patients, this posterior ankle pain is often the result of impingement of an accessory bone of the lower extremity, the os trigonum. This ossicle can become entrapped between the posterior tibia and calcaneus during maneuvers involving the extreme plantar-flexed ankle positions of pointe and
Complaints
surgeon
(LJM).
Operative technique The patient was positioned supine on the operating table with a trochanteric roll under the hip of the involved side. A pneumatic tourniquet was used high on the ipsilateral thigh. After sterile prepping and draping of the lower extremity below the knee, the limb was exsanguinated and the tourniquet inflated. A lateral approach to the ossicle was then initiated. A 3-cm straight incision was made at the posterior lateral ankle, posterior to the peroneal tendons as they approach the tip of the lateral malleolus. Care was taken to identify and protect the sural nerve and its branches in this area. Deeper dissection through the subcutaneous tissue was directed toward the posterior ankle joint and the
demi-pointe. t Address correspondence and reprint requests to: Lyle J. Micheli, MD, Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115. 533
534
capsule was identified. The capsule was opened in line with the skin incision over the os trigonum, which was palpable at the posterior lateral margin of the talus. Sharp dissection was then used to excise the ossicle in its entirety. Because much of the os trigonum is cartilaginous, it frequently occupies a larger area than is first appreciated by plain radiographs. Care was taken to avoid injury to the flexor hallucis longus tendon, the tibial nerve, the posterior tibial artery, and the posterior tibial tendon on the medial side of the
patients noted symptoms with more moderate dance participation or day-to-day activities, but again, this did not limit their ability to perform.
ossicle. After resection of the os trigonum, ranging of the joint was done to ensure that there was no additional impingement from an elongated posterior process of the talus or inflammatory fibrous tissue; these may be excised using osteotomes or rongeurs. The capsule and subcutaneous layers were loosely approximated using absorbable sutures, and the skin was closed with interrupted nylon stitches. A dressing was applied and the limb immobilized in a short leg, posterior, plaster splint. The tourniquet was deflated before wound closure to check for excessive bleeding. The patients were usually discharged on the day after surgery. They were instructed to remain nonweightbearing with crutches. At the initial follow-up visit 3 to 5 days after surgery, the splint was removed and formal physical therapy for progressive weightbearing and range of motion was initiated. Use of crutches was discontinued when the patient was comfortable without support. It is essential to stress early return of full activity and weightbearing. Strengthening and gradual return to bar activities and center work are progressed as healing permits.
The average length of postoperative immobilization before physical therapy was 11 days (range, 3 to 28). The average length of postoperative formal physical therapy was 10 weeks (range, 1 to 41). One patient still required antiinflammatory medications for symptoms on occasion. Five patients still performed specific therapy exercises for their ankle, in
RESULTS
’
The 12 patients (15 ankles) reviewed in the study included 9 women and 3 men. Nine of the patients were professional ballet dancers, and 3 were students of advanced ballet schools. There were 7 right ankles and 8 left ankles included. The average age of the patients at the time of surgery was 23 years (range, 14 to 34). The average followup was 28 months. Preoperative symptoms included activity-limiting pain in all cases. There were varying amounts of stiffness, weakness, swelling, or numbness noted subjectively by the patients as well. Activities noted to worsen symptoms included pointe work (in all patients), jumping, and center work. All of the patients had been treated conservatively with various modalities including heat, ice, massage, flexibility exercises, ultrasound, nonsteroidal antiinflammatory medication, and whirlpool treatments. The average treatment course before surgery was 4 months (range, 1 to 12). All patients failed to achieve sufficient relief of symptoms with these conservative therapies and were unable to participate in full dance activities. In the postoperative period, four patients reported they had no pain or other symptoms during their dance activity. Six patients had occasional symptoms during heavy dance participation, but this did not limit their routines. Two
All of the professional dancers were able to return to full participation without restriction. The average time to full activity for these patients was 3 months (range, 1.5 to 12). Two of the three students returned to full dance activities and one student decided to curtail her dance career for other reasons.
addition to their normal dance warm-up routine. Complications of the procedure included one male dancer who developed a superficial wound infection that required intravenous and subsequent oral antibiotics with dressing changes of the area. A second male patient suffered a transient tibial nerve sensory neurapraxia of the involved foot postoperatively. This sensory deficit gradually returned to normal over a period of 1 year. Neither of these complications resulted in permanent sequela. In addition, a number of these patients reported an increased range of plantar flexion after removal of the os trigonum. This, unfortunately, could not be documented from our available data.
DISCUSSION The incidence of radiologically detectable os trigonum has been reported between 3% and 13% in the general population. It is twice as common unilaterally as bilaterally. Turners in 1882 was the first to describe this structure as a distinct but infrequent ossicle, separate from the posterior border of the talus and containing a groove for the tendon of the flexor hallucis longus (Fig. 1). Earlier anatomists
1. Drawings of the dorsal view of the talus showing associated os trigonum on the left and a fused lateral (posterior) tubercle on the right. A, dorsal articular surface of the talus; B, articular surface for the fibular malleolus; C, os trigonum; D, groove for the flexor hallucis longus tendon; E, medial tubercle; and F, fused lateral (posterior) tubercle.
Figure
an
535
considered the
os trigonum to be a fracture of the posterior of the talus. portion The talus normally contains two prominent tubercles. The lateral tubercle is larger and commonly referred to as the posterior process. Attached to this lateral tubercle is the posterior talofibular ligament of the ankle joint. The deltoid ligament is attached to the base of the medial tubercle. The flexor hallucis longus tendon runs between these two processes in its own small groove. These tuberosities appear as secondary centers of ossification between the 8th and llth year of age and quickly unite with the main bone within a year. The origin of the os trigonum is as a persistent separation of the secondary center of the lateral tubercle from the remainder of the posterior talus. This separation may be a result of repeated trauma during development, but this has never been proven. Acute fractures of the posterior tubercle do occur, and these are distinguished by their sharp outline and associated history of sudden injury to this area. The radiographic appearance of an os trigonum can be confused with an osteophyte of the posterior ankle or subtalar joints. Heterotopic calcification in the surrounding soft tissues of the area also has a similar appearance (Fig. 2). Symptoms of os trigonum impingement, as noted in our study and by others, include recurrent pain with stiffness, tenderness, and swelling behind the ankle in the space anterior to the Achilles tendon. This is especially noticeable during pointe work in dancing. Although not seen in our study group, others have suggested that some cases of flexor hallucis longus tendinitis may be secondary to an impingent os trigonum. This can create pain during motion of the great
at the plantar aspect of the foot, and curling of the toes are also typical compensatory problems that result from efforts to force the foot into a better
sprains. Calf strains, pain pointe position.
The os trigonum is frequently palpable at the posterolateral jointline of the ankle. Surrounding soft tissue swelling may also be found. Pain is elicited with forceful passive plantar flexion of the foot. A sudden end point to motion is encountered. If flexor hallucis longus tendinitis is present, flexion and extension of the great toe may cause pain near the region of the impingent ossicle. Radiographic confirmation of the diagnosis involves plain films of the ankle, including a lateral view in maximum plantar flexion (Fig. 3). We frequently have the dancers assume their best pointe or demi-pointe positions and document the posterior block to further motion. The ossicle is seen entrapped between the posterior lip of the tibia and the dorsum of the calcaneus. Since much of the entrapment can involve cartilaginous as well as fibrous tissue and inflammatory swelling, a computed tomography scan of the area can outline a more detailed picture of the uncalcified structures involved. Bone scans often show increased uptake in this region of traumatized tissue (Fig. 4). Confirmation of the diagnosis can be made by injecting the area with a short-acting local anesthetic. This should relieve the painful symptoms, but not change the maximum ankle range of motion significantly.
toe.
Rest from dance toms of
os
activity will usually diminish the symptrigonum impingement, although recurrence is
quite common with return to activities. Many dancers attempt to compensate for lost ankle plantar flexion by malaligning the foot into undesirable positions. Signs of this malalignment include &dquo;sickling&dquo; of the foot (inversion posturing). This may overload the anterior lateral ankle ligaments and contribute to frequent ankle
Figure 2. A lateral dorsiflexion showing
radiograph of the hindfoot large os trigonum (arrow).
a
in neutral
Figure 3. A lateral radiograph of a dancer’s foot in maximum plantar flexion (the demi-pointe position) showing impingement of an os trigonum between the posterior aspect of the tibia and the calcaneus (arrow).
536
cannot be quantified by our study. Unfortunately, the high demand of participation involved in serious ballet activity often precludes successful conservative management. We have found that in some patients, the impingement created by the offending ossicle is far too restrictive to allow the proper alignment of leg, foot, and toes in an aesthetically
pleasing and functionally stable position adequate for
Figure 4. Technetium 99m bone scan of a dancer with painful trigonum demonstrating increased uptake.
os
The differential diagnosis of os trigonum impingement includes flexor hallucis longus tendinitis as caused by other factors, peroneal tendinitis, Achilles tendinitis, retrocalcaneal bursitis, ankle joint arthritis, or acute fractures of the talar tuberosities. Conservative treatment of this syndrome includes limitation or abandonment of the extreme ankle/ foot positions that exacerbate symptoms. Oral antiinflammatory medication can also be used to diminish tendinitis and the localized irritation. Local steroid injection to the area is discouraged since this may lead to tendon rupture, a
devastating outcome in this population. Physical therapy treatment, including icing, ultrasound treatments, whirlpool, massage, flexibility work, and training modification, can permit resolution of acute inflammation while increasing range of motion and strength. Therapists must encourage proper dance technique to avoid malalignment compensation. Success of conservative management depends on many unidentified factors and
con-
tinued dance activity. Surgical excision of the os trigonum was successful in relieving symptoms of posterior ankle impingement in our patients. Although 67% of the patients still had occasional pain in the operative area, all professional-level dancers and two of three student-level dancers were able to return to full and unrestricted dance participation with good success. Attention to anatomic detail and aggressive postoperative rehabilitation are important aspects in successful surgical outcome. The long-term effects of os trigonum resection are still unknown. The main short-term goal, returning dancers to high levels of activity, seems readily obtainable using this surgical procedure. We recommend this treatment for serious dancers suffering from os trigonum impingement syndrome in whom conservative therapies have failed to resolve
symptoms. REFERENCES 1. Hamilton WG: and posterior
Stenosing tenosynovitis of the flexor hallucis longus tendon impingement upon the os trigonum in ballet dancers. Foot
Ankle 3: 74-80, 1983 2. Howse AJ: Posterior block of the ankle joint in dancers. Foot Ankle 3: 81-
84, 1983 3.
Kleiger B: The posterior tibiotalar impingement syndrome in dancers. Bull Hosp Jt Dis Orthop Inst 47: 203-210, 1987 McDougall A: The os trigonum. J Bone Joint Surg 37B: 257-265, 1955
4. 5. Sammarco GJ: The foot and ankle in classical ballet and modem dance, in Jahss MH (ed): Disorders of the Foot. Philadelphia, WB Saunders, 1982, pp 1626-1659 6. Turner W: A secondary astragalus in the human foot. J Anat Physiol 17:
82-83,1882
trigonum impingement in dancers* JOSEPH J. MAROTTA, MD, AND LYLE J. MICHELI,† MD From The Children’s
Hospital, Boston,
Massachusetts
i
This problem has variously been named the os trigonum syndrome, talar compression syndrome, posterior ankle impingement syndrome, and posterior tibiotalar impingement syndrome.1-3 Although rarely noted in the general public, it has been described in gymnasts and dancers, particularly in ballet dancers, who forcefully point the foot into an artistically desirable, straight and rigid, high-arched, shock-absorbing platform.4.5 Earlier studies have outlined the pathomechanics and clinical presentation of this syndrome.l~2 We have reviewed a series of patients treated surgically by resection of the os trigonum to determine the clinical outcome of this therapeu-
ABSTRACT Sixteen
underwent surgical excision of an imossicle pinging through a posterior lateral approach. Twelve of these patients (15 ankles) were available for followup and were retrospectively surveyed at an average of 28 months after surgery. There were 9 women and 3 men. Nine were professional ballet dancers and 3 were students of advanced ballet schools. Preoperative symptoms included pain localized to the posterior ankle, limitation of motion, weakness, swelling, or neurologic changes associated with dance activities. All patients were severely hampered in their dance participation and had failed nonsurgical therapies. Postoperatively, all patients followed an aggressive rehabilitation protocol. All had improvement in their impingement symptoms; eight (67%) still had occasional discomfort. All professional dancers returned to unrestricted dance activity. The mean time to full activity was 3 months. One patient had a superficial wound infection requiring antibiotic treatment and another suffered a transient tibial nerve neurapraxia. Both of these complications resolved without sequelae. We conclude that posterior ankle impingement in ballet dancers, caused by an os trigonum and resistant to nonsurgical therapies, is effectively treated with simple excision of the offending structure.
patients
tic intervention.
MATERIALS AND METHODS Sixteen patients who suffered from posterior ankle impingement secondary to a radiologically identifiable os trigonum underwent resection of the ossicle when conservative measures failed to resolve symptoms. The procedures were performed between March 1984 and November 1989. Four patients were lost to followup, leaving 12 patients (15 ankles) who were contacted and surveyed. They were asked about their pre- and postoperative function, activity limitations, symptoms, prior treatment modalities, rehabilitation course, time to full participation, and ongoing treatments or problems. All procedures were performed under the direction of one
of posterior ankle pain are relatively common in ballet dancers. The differential diagnosis of this complaint includes tendinitis, capsulitis, and mechanical impingement of the posterior elements of the talus between the posterior tibia and calcaneus. In a relatively high proportion of these patients, this posterior ankle pain is often the result of impingement of an accessory bone of the lower extremity, the os trigonum. This ossicle can become entrapped between the posterior tibia and calcaneus during maneuvers involving the extreme plantar-flexed ankle positions of pointe and
Complaints
surgeon
(LJM).
Operative technique The patient was positioned supine on the operating table with a trochanteric roll under the hip of the involved side. A pneumatic tourniquet was used high on the ipsilateral thigh. After sterile prepping and draping of the lower extremity below the knee, the limb was exsanguinated and the tourniquet inflated. A lateral approach to the ossicle was then initiated. A 3-cm straight incision was made at the posterior lateral ankle, posterior to the peroneal tendons as they approach the tip of the lateral malleolus. Care was taken to identify and protect the sural nerve and its branches in this area. Deeper dissection through the subcutaneous tissue was directed toward the posterior ankle joint and the
demi-pointe. t Address correspondence and reprint requests to: Lyle J. Micheli, MD, Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115. 533
534
capsule was identified. The capsule was opened in line with the skin incision over the os trigonum, which was palpable at the posterior lateral margin of the talus. Sharp dissection was then used to excise the ossicle in its entirety. Because much of the os trigonum is cartilaginous, it frequently occupies a larger area than is first appreciated by plain radiographs. Care was taken to avoid injury to the flexor hallucis longus tendon, the tibial nerve, the posterior tibial artery, and the posterior tibial tendon on the medial side of the
patients noted symptoms with more moderate dance participation or day-to-day activities, but again, this did not limit their ability to perform.
ossicle. After resection of the os trigonum, ranging of the joint was done to ensure that there was no additional impingement from an elongated posterior process of the talus or inflammatory fibrous tissue; these may be excised using osteotomes or rongeurs. The capsule and subcutaneous layers were loosely approximated using absorbable sutures, and the skin was closed with interrupted nylon stitches. A dressing was applied and the limb immobilized in a short leg, posterior, plaster splint. The tourniquet was deflated before wound closure to check for excessive bleeding. The patients were usually discharged on the day after surgery. They were instructed to remain nonweightbearing with crutches. At the initial follow-up visit 3 to 5 days after surgery, the splint was removed and formal physical therapy for progressive weightbearing and range of motion was initiated. Use of crutches was discontinued when the patient was comfortable without support. It is essential to stress early return of full activity and weightbearing. Strengthening and gradual return to bar activities and center work are progressed as healing permits.
The average length of postoperative immobilization before physical therapy was 11 days (range, 3 to 28). The average length of postoperative formal physical therapy was 10 weeks (range, 1 to 41). One patient still required antiinflammatory medications for symptoms on occasion. Five patients still performed specific therapy exercises for their ankle, in
RESULTS
’
The 12 patients (15 ankles) reviewed in the study included 9 women and 3 men. Nine of the patients were professional ballet dancers, and 3 were students of advanced ballet schools. There were 7 right ankles and 8 left ankles included. The average age of the patients at the time of surgery was 23 years (range, 14 to 34). The average followup was 28 months. Preoperative symptoms included activity-limiting pain in all cases. There were varying amounts of stiffness, weakness, swelling, or numbness noted subjectively by the patients as well. Activities noted to worsen symptoms included pointe work (in all patients), jumping, and center work. All of the patients had been treated conservatively with various modalities including heat, ice, massage, flexibility exercises, ultrasound, nonsteroidal antiinflammatory medication, and whirlpool treatments. The average treatment course before surgery was 4 months (range, 1 to 12). All patients failed to achieve sufficient relief of symptoms with these conservative therapies and were unable to participate in full dance activities. In the postoperative period, four patients reported they had no pain or other symptoms during their dance activity. Six patients had occasional symptoms during heavy dance participation, but this did not limit their routines. Two
All of the professional dancers were able to return to full participation without restriction. The average time to full activity for these patients was 3 months (range, 1.5 to 12). Two of the three students returned to full dance activities and one student decided to curtail her dance career for other reasons.
addition to their normal dance warm-up routine. Complications of the procedure included one male dancer who developed a superficial wound infection that required intravenous and subsequent oral antibiotics with dressing changes of the area. A second male patient suffered a transient tibial nerve sensory neurapraxia of the involved foot postoperatively. This sensory deficit gradually returned to normal over a period of 1 year. Neither of these complications resulted in permanent sequela. In addition, a number of these patients reported an increased range of plantar flexion after removal of the os trigonum. This, unfortunately, could not be documented from our available data.
DISCUSSION The incidence of radiologically detectable os trigonum has been reported between 3% and 13% in the general population. It is twice as common unilaterally as bilaterally. Turners in 1882 was the first to describe this structure as a distinct but infrequent ossicle, separate from the posterior border of the talus and containing a groove for the tendon of the flexor hallucis longus (Fig. 1). Earlier anatomists
1. Drawings of the dorsal view of the talus showing associated os trigonum on the left and a fused lateral (posterior) tubercle on the right. A, dorsal articular surface of the talus; B, articular surface for the fibular malleolus; C, os trigonum; D, groove for the flexor hallucis longus tendon; E, medial tubercle; and F, fused lateral (posterior) tubercle.
Figure
an
535
considered the
os trigonum to be a fracture of the posterior of the talus. portion The talus normally contains two prominent tubercles. The lateral tubercle is larger and commonly referred to as the posterior process. Attached to this lateral tubercle is the posterior talofibular ligament of the ankle joint. The deltoid ligament is attached to the base of the medial tubercle. The flexor hallucis longus tendon runs between these two processes in its own small groove. These tuberosities appear as secondary centers of ossification between the 8th and llth year of age and quickly unite with the main bone within a year. The origin of the os trigonum is as a persistent separation of the secondary center of the lateral tubercle from the remainder of the posterior talus. This separation may be a result of repeated trauma during development, but this has never been proven. Acute fractures of the posterior tubercle do occur, and these are distinguished by their sharp outline and associated history of sudden injury to this area. The radiographic appearance of an os trigonum can be confused with an osteophyte of the posterior ankle or subtalar joints. Heterotopic calcification in the surrounding soft tissues of the area also has a similar appearance (Fig. 2). Symptoms of os trigonum impingement, as noted in our study and by others, include recurrent pain with stiffness, tenderness, and swelling behind the ankle in the space anterior to the Achilles tendon. This is especially noticeable during pointe work in dancing. Although not seen in our study group, others have suggested that some cases of flexor hallucis longus tendinitis may be secondary to an impingent os trigonum. This can create pain during motion of the great
at the plantar aspect of the foot, and curling of the toes are also typical compensatory problems that result from efforts to force the foot into a better
sprains. Calf strains, pain pointe position.
The os trigonum is frequently palpable at the posterolateral jointline of the ankle. Surrounding soft tissue swelling may also be found. Pain is elicited with forceful passive plantar flexion of the foot. A sudden end point to motion is encountered. If flexor hallucis longus tendinitis is present, flexion and extension of the great toe may cause pain near the region of the impingent ossicle. Radiographic confirmation of the diagnosis involves plain films of the ankle, including a lateral view in maximum plantar flexion (Fig. 3). We frequently have the dancers assume their best pointe or demi-pointe positions and document the posterior block to further motion. The ossicle is seen entrapped between the posterior lip of the tibia and the dorsum of the calcaneus. Since much of the entrapment can involve cartilaginous as well as fibrous tissue and inflammatory swelling, a computed tomography scan of the area can outline a more detailed picture of the uncalcified structures involved. Bone scans often show increased uptake in this region of traumatized tissue (Fig. 4). Confirmation of the diagnosis can be made by injecting the area with a short-acting local anesthetic. This should relieve the painful symptoms, but not change the maximum ankle range of motion significantly.
toe.
Rest from dance toms of
os
activity will usually diminish the symptrigonum impingement, although recurrence is
quite common with return to activities. Many dancers attempt to compensate for lost ankle plantar flexion by malaligning the foot into undesirable positions. Signs of this malalignment include &dquo;sickling&dquo; of the foot (inversion posturing). This may overload the anterior lateral ankle ligaments and contribute to frequent ankle
Figure 2. A lateral dorsiflexion showing
radiograph of the hindfoot large os trigonum (arrow).
a
in neutral
Figure 3. A lateral radiograph of a dancer’s foot in maximum plantar flexion (the demi-pointe position) showing impingement of an os trigonum between the posterior aspect of the tibia and the calcaneus (arrow).
536
cannot be quantified by our study. Unfortunately, the high demand of participation involved in serious ballet activity often precludes successful conservative management. We have found that in some patients, the impingement created by the offending ossicle is far too restrictive to allow the proper alignment of leg, foot, and toes in an aesthetically
pleasing and functionally stable position adequate for
Figure 4. Technetium 99m bone scan of a dancer with painful trigonum demonstrating increased uptake.
os
The differential diagnosis of os trigonum impingement includes flexor hallucis longus tendinitis as caused by other factors, peroneal tendinitis, Achilles tendinitis, retrocalcaneal bursitis, ankle joint arthritis, or acute fractures of the talar tuberosities. Conservative treatment of this syndrome includes limitation or abandonment of the extreme ankle/ foot positions that exacerbate symptoms. Oral antiinflammatory medication can also be used to diminish tendinitis and the localized irritation. Local steroid injection to the area is discouraged since this may lead to tendon rupture, a
devastating outcome in this population. Physical therapy treatment, including icing, ultrasound treatments, whirlpool, massage, flexibility work, and training modification, can permit resolution of acute inflammation while increasing range of motion and strength. Therapists must encourage proper dance technique to avoid malalignment compensation. Success of conservative management depends on many unidentified factors and
con-
tinued dance activity. Surgical excision of the os trigonum was successful in relieving symptoms of posterior ankle impingement in our patients. Although 67% of the patients still had occasional pain in the operative area, all professional-level dancers and two of three student-level dancers were able to return to full and unrestricted dance participation with good success. Attention to anatomic detail and aggressive postoperative rehabilitation are important aspects in successful surgical outcome. The long-term effects of os trigonum resection are still unknown. The main short-term goal, returning dancers to high levels of activity, seems readily obtainable using this surgical procedure. We recommend this treatment for serious dancers suffering from os trigonum impingement syndrome in whom conservative therapies have failed to resolve
symptoms. REFERENCES 1. Hamilton WG: and posterior
Stenosing tenosynovitis of the flexor hallucis longus tendon impingement upon the os trigonum in ballet dancers. Foot
Ankle 3: 74-80, 1983 2. Howse AJ: Posterior block of the ankle joint in dancers. Foot Ankle 3: 81-
84, 1983 3.
Kleiger B: The posterior tibiotalar impingement syndrome in dancers. Bull Hosp Jt Dis Orthop Inst 47: 203-210, 1987 McDougall A: The os trigonum. J Bone Joint Surg 37B: 257-265, 1955
4. 5. Sammarco GJ: The foot and ankle in classical ballet and modem dance, in Jahss MH (ed): Disorders of the Foot. Philadelphia, WB Saunders, 1982, pp 1626-1659 6. Turner W: A secondary astragalus in the human foot. J Anat Physiol 17:
82-83,1882
