The ankle is a crucial joint to understand in the context of dance injuries because it is the connection between the leg and the foot that establishes lower limb stability. It is one of the most commonly injured body areas in dance.
Incidences of injury to the ankle-foot complex scale from 27% to 49% of total injuries in ballet, modern, flamenco, and tap dancers.
Dancer’s tendonitis is also referred to as Flexor Hallucis Longus (FHL) tendonitis which is an overuse injury in which repetitive Plantarflexion and Dorsiflexion (pointing and flexing) of the foot results in inflammation of the FHL tendon.
Dancer's Tendonitis
In dancers, injury to the FHL is usually provoked by the recurrent movement caused by changing position from a plié position to a relevé position. (Plié is a French term meaning to bend, relevé, is a ballet term meaning “raised.”
The term relevé explains the action when a dancer rises up on their toes). This movement of action produces a force that is ten times the dancer's body weight.
The Flexor Hallucis Longus (FHL) has been also called as the ‘Achilles of the foot’ due to its unique role controlling midfoot pronation and supination, and its physiological and mechanical properties, which permit it to act as a powerful convertor of force from the rear foot all the way through to the big toe.
Due to its anatomical arrangement and its unique actions, it is a muscle-tendon unit that can often become injured in athletic populations. This is often called the ‘dancer's tendonitis’ because it is so prevalent in classic ballet dancers. However, it's going to affect any sport which requires repetitive push-off and extreme plantarflexion such as swimmers, sprinters, footballers and gymnasts.
Relevant Anatomy and Biomechanics
The FHL arises from the posterior and distal two-thirds of the fibula, the interosseous membrane of the limb and to the intermuscular septa. It's distal and lateral to the muscle belly of the flexor digitorum longus (FDL) and deep to the soleus and gastrocnemius.
It is pennate in shape and therefore the fibres of the muscle continue and converge on its tendon because it crosses the posterior surface of the lower tibia.
The FHL tendon then passes posterior to the talus and deep to the medial retinacular structures at the posteromedial ankle.
It is surrounded within a synovial sheath and passes through a fibro-osseous tunnel between the medial retinaculum and therefore the lateral tubercles of the talus. Because it turns to course towards the arch, it sits below the sustentaculum tali, which forms a horizontal sheath of bone on the Calcaneus.
Injury to FHL occurs when the dancer is not fulfilling the natural requirements of movement through the joints.
For instance, when executing relevé it creates sickling and unstable foot positions because their forefoot is not strong enough and the limb external rotation and hip joint muscular support are not synchronous with the heel raises.
In contrast, when executing plié, the result of poor control of weakened foot muscles is due to strain on the passive supporting structures, like the plantar ligaments, ankle joint capsules, and plantar fascia, etc.
This result in faulty bone alignment, increased bone load, and risk of overuse syndromes in different tissues.
Both these manoeuvers put tremendous strain on the ankles and feet because the bones are loaded in weight-bearing and the soft tissues must tether the bones sufficiently to control their positions and minimize the occurrence of injury.The FHL is, therefore a part of the tarsal tunnel, and within the tunnel, it lies posterior to the neurovascular bundle. As the tendon of FHL moves through the arch of the foot, it crosses over the FDL tendon to lie on top of it. This is termed as the ‘knot of Henry’.
At this level, the FHL is dorsal to the medial edge of the plantar fascia. This tendon continues to extend between the two sesamoid bones of the first metatarsophalangeal (MTP) joint where it is covered by the intersesamoid ligament and inserts at the base of the distal phalanx of the great toe.
The FHL therefore, associates with three retinacular structures (at the tarsal tunnel, Knot of Henry and inter-sesamoid ligament) and this has implications for generating abnormal compression and stress on the tendon that can lead to an injury.
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| Dancer's Tendonitis |
Causes
While the accurate cause of FHL injury is debated, it is thought that constriction occurs at the fibro-osseous tunnel in the posterior ankle in and around the tarsal tunnel or the Knot of Henry in the midfoot or intersesamoid ligament.
This pseudo- entrapment generates repetitive microtrauma, usually occurs due to gradual wear and tear associated with overuse.
Although irritation may happen at the knot of Henry and within the sesamoids of the great toe, the most commonly irritated location is deep to the flexor retinaculum, where the tendon lies within the fibro-osseous tunnel.
Recurrent irritation of the tendon’s sheath can lead to hypertrophy of the tendon within this tunnel. Thickening or fibrosis may impede the normal gliding of the tendon, thus creating pain and movement restrictions.
Increased pain and decreased use can cause weakness of the tendon and muscle. Adhesions and the development of calcific nodules can follow.
When the foot is fully plantarflexed, the relative inconsistency among the FHL and the fibro-osseous tunnel exists. This might cause abnormal stresses and resultant tenosynovitis to the FHL tendon.
Injury at the level of the talus may also occur due to an abrupt change in direction of the tendon at this level. Other likely causes can relate to a low-lying FHL muscle belly or an accessory FDL.
Immunohistochemical studies on cadaveric tendons have recognised avascular zones where the tendon wraps around the talus and where the tendon intersects the first metatarsal head.
This can all be combined by the high tensile loads imposed on the FHL tendon as a dancer/athlete jumps and lands and absorbs shock through the foot and thus FHL tendon.
Dancer’s tendonitis is more common in female ballet dancers who spend plenty of time en pointe or demi-pointe. FHL tendonitis can occur as a primary condition, or as a secondary condition of os trigonum impingement syndrome.
Failure to accurately treat inflammation may result in a nodule (obstruction of the fibrous tunnel the tendon runs through) or partial or complete tear of the tendon.
Dancers are exposed to a wide range of risk factors for this kind of injury. The most common issues that cause injuries are:
- Type of dance and frequency of classes, rehearsals, and performances
- Duration of training
- Environmental conditions like hard floors and cold studios etc.
- Equipment used, especially shoes
- Individual dancer's body alignment
- Prior history of injury
- Nutritional deficiencies
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| Dancer's Tendonitis |
Subjective Assessment
Injury to the FHL tendon is typically characterized by pain situated posterior and inferior to the medial malleolus, which gets worse by jumping and landing or going from demi-pointe to full pointe.
Demi-pointe position in ballet is when the dancer is on the balls of their feet, referred to as half-point and Full Point (en pointe position) is when the dancer has a completely extended vertical foot).
In dancers, the FHL tendon is typically compressed while performing a relevé position and is overstretched while performing a plié position. In such cases, the dancer will feel pain around the posteromedial ankle when performing the plié.
This can also be incorporated with a sensation of crepitus in the tendon and triggering of the great toe depending on the severity of the tendon injury.
Triggering can also involve an inability to relax the toe after full plantar flexion when pointing the foot, resulting in a locking sensation of the great toe.
That is also usually painful because as a result, when it begins to fray, the tendon gets swollen, irritated, and inflamed, their fluid accumulates around that area, and the patient experiences swelling and pain.
Objective Assessment
Clinical examination of the foot and ankle in a dancer with a suspected FHL injury involves specific attention to four regions of the foot and ankle:
- Posterior ankle
- sustentaculum tali
- Plantar midfoot
- The level of the sesamoids
The ankle and great toe are held in either a neutral or dorsiflexed position to put the FHL under tension. Proximally, the muscle and the musculotendinous junction are palpated just posterior and lateral to the posterior tibial tendon.
Medially and inferior to the sustentaculum tali, the FHL is often palpated as it passes through the fibro-osseous tunnel. At the plantar surface, the FHL can be found just plantar to the navicular and medial cuneiform bone, and it can often be palpated as it traverses the knot of Henry. Distally, the FHL is palpated while it travels between the sesamoids.
There will also be pain with resisted flexion of the hallux IP joint. Great toe triggering can be felt with active or passive motion with no tenderness at the level of the first metatarsal head.
Resistance to the FHL could also be painful. Often, one can best elicit pain by placing the ankle in the plantar flexion and pressing on the FHL tendon area while moving the great toe into a forced dorsiflexion position.
This will result in pain and tenderness at the point of manual compression in the posterior ankle region. Pseudo-hallux rigidus may be present, as illustrated by a limitation of great toe dorsiflexion with the knee fully extended and the ankle in full dorsiflexion. Symptoms can be further provoked with ankle inversion. It can decrease the dimension of the tarsal tunnel causing more compression or irritation to the FHL tendon.
Positive Tomasen test: This test assesses the influence of the FHL on the first MTP motion. This test is performed by assessing first MTP motion in both positions that is, in maximal plantarflexion and moderate dorsiflexion of the ankle. To perform the test accurately, the first metatarsal head should be stabilized to avoid compensatory first metatarsal head plantar flexion.
A positive test consists of discomfort or reduced first MTP joint extension by 20 degrees with ankle dorsiflexion.
When you allow the patient to release the foot and to now plantarflex and point the foot, then they will have a better range of motion of the big toe. So this occurs because when putting the foot into dorsiflexion, it makes that tendon taut.
Diagnostic Procedures
X-Rays will not provide an accurate diagnosis of FHL injuries. Nevertheless, X-Rays is good for ruling out fractures that can cause an impingement of the FHL tendon (calcaneus, distal medial malleolus, or os trigonum). A comprehensive patient history, followed by a full physical examination is usually critical for accurately diagnosing this condition.
On the other hand, in some cases, MRI is required to evaluate tears in the FHL tendon and any sources of impingement of the FHL. One of the best diagnostic examinations for FHL tendonitis condition is dynamic ultrasound.
This allows real-time testing of the FHL tendon while it goes through a range of motion. Ultrasound often can be the option for the diagnosis of stenosis or impingement of a low-lying muscle.
Often, one can combine ultrasound with MRI to check for os trigonum problems or posterior ankle impingement.
Differential Diagnosis
- Posterior ankle impingement syndrome (PAIS)
- Tarsal tunnel syndrome
- Os trigonum syndrome
- An osteochondritis dissecans lesion of the posterior talar dome
- Early arthritis or degeneration of the posterior facet of the subtalar joint
- A fibrous middle facet tarsal coalition
- Posterior tibial or Achilles tendinitis or strain
- Tibialis posterior tendinopathy
- Plantar fasciitis
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| Dancer's Tendonitis |
Treatment
If FHL tendonitis is diagnosed, avoid pointe work until the inflammation subsides. Also, take an inventory of the dancer’s technique- specifically the alignment of the feet.
Forcing turnout to the extreme results in the inner ridge of the foot to roll in, which may either lead to or exacerbate the symptoms.
Conservative management includes anti-inflammatory drugs, ice, and physiotherapy. Surgery should be considered when all other approaches fail. Recovery from FHL surgery may take over three months.
One of the essential components of treatment is that the patient should take relative rest from any activity that elicits their pain until its symptom-free (crutches may be required in some cases).
This permits the body to initiate the healing process in the absence of further tissue damage. Once the patient can achieve these activities pain-free, a gradual return to these activities is indicated provided there is no aggregation of symptoms.
Neglecting symptoms or adopting a ‘no pain, no gain’ attitude is likely to lead to the injury becoming chronic. Once chronic, healing slows down significantly resulting in markedly increased recovery time and an increased likelihood of future episodes of recurrence. Immediate appropriate therapy in all patients with FHL tendonitis is important to ensure an optimal outcome.
Manual therapy combined with a functional exercise program is particularly powerful and effective for achieving a full resolution.
It might take at least four to six weeks of conservative treatment for a complete recovery. Often, all activities cannot be resumed until the pain symptoms have fully subsided.
Even after the pain intensity has subsided, a slow return to activities is recommended. In the case of dancers, this could indicate initially avoiding point work, jumps, or grand plies (a grand plié requires a full knee bend).
Conservative Care for Dancer’s Tendonitis
- Following Peace and Love protocol particularly with regular icing and anti-inflammatory medication can help to significantly reduce inflammation in the initial phase of this condition. Following appropriate nutritional, dietary, and possible pharmaceutical recommendations are also necessary.
- Activity Modifications: Reduction in activities that precipitate pain is necessary to promote healing. for instance, avoid cessation of pointe work, jumps or grand plies etc.
- Pain Management
- Supports (crutches or walker boot) can seldom be beneficial (in the short term).
- Motion specific release techniques.
- Taping of the foot and ankle.
- Introduce target specific exercises that support the improvement in strength, flexibility, and balance: As symptoms subside, stretching and range of motion exercises are added in a pain-free range to aid restore normal range of motion. Special attention should be given to the stretching of triceps surae since female ballet dancers tend to have limited ankle-foot dorsiflexion range. Adequate dorsiflexion ROM may help with the absorption of high landing forces, avoidance of compensatory pronation, and prevention of double heel strikes during landing from jumps.
- Stretching: Calf and FHL stretch can be started in a pain-free range. For FHL stretch, place the big toe on a block into a dorsiflexed position and bring the knee towards the wall. Hold it for 20-30 seconds.
- Improve Joint ROM: Ankle & Foot Mobilization: Improving joint mobility is critical if addressing the body's full kinetic chain. The objective of joint mobilization is to reverse adverse physiological changes by promoting movement between capsular fibers.
- Ankle and Foot Strengthening: Isolated muscle strengthening for an injured FHL muscle and tendon can involve the following type of exercises. These are listed as progressions with the first exercises being non-weight-bearing exercises, and the later examples being suitable alternatives when the athlete can fully weight-bear. All these exercises are designed to be performed in subtalar joint neutral positions so the athlete will require to be cued and coached on how to maintain a neutral position.
- Resisted big toe plantar-flexion: Using resistance bands or tubing, wrap around the big toe. With light to medium resistance pull to bands/ tubing, start actively plantar-flexing the big toe and foot. Hold for 8-10 seconds. Slowly resist the pull back into a neutral position.
- Eccentric FHL strengthening: In a seated position, Wrap the resistance band around the great toe. keep the foot in dorsiflexion and eversion and push the band all the way down in plantarflexion and inversion against the resistance.
3. Towel scrunch with a heel lift: Place towel onto a smooth surface, such as tile or wooden floors; place a foot onto the towel. Actively begin to scrunch the big toe balling towel under toes. At the same time lift the heel off the towel (heel and big toe should be the plantar-flexed position if performed correctly). Place heel back onto the towel and dorsiflex big toe to begin the sequence again. Should perform until the towel is completely underfoot. This can be performed from seated or standing positions.
4. Marble/ ball pickups: Using 1st and 2nd toes, dorsiflex to pick up marble/ball and drop into a cup/ container utilizing plantar-flexion. Should be performed from a standing position.
5. Edge hovers: Standing on the edge of a step with the 1st and 2nd toes supported with the three outside toes hovering in space, actively press the 1st toe into the step and try to lift and hold the heel off the step. These can be held for 15-20 second holds.
6. Gastrocnemius and soleus complex strengthening: In standing position, perform relevé on a step by keeping a big toe outside a step and push up into a relevé position. This exercise helps in strengthening the gastrocnemius and soleus complex.
- Proprioceptive exercises: Proprioceptive exercises play a key role in the rehabilitation process for the ankle-foot, as some injuries have been shown to impair reflex responses. These types of exercises are designed to challenge the ankle-foot complex using relatively unstable surfaces like wobble boards, ankle discs, etc. with increasing challenges incorporated to promote rapid neuromuscular responses such as adding relevés, closing the eyes, or catching weighted balls.
- Biomechanical corrective techniques: One of the most important aspects of treatment is retraining the biomechanics of the foot and ankle to prevent the injury from reoccurring. This involves not only the muscles in the feet but also your core and turnout muscles to make sure that the correct alignment of the leg can be maintained at all times. Often a Floor Barre is used to continue to maintain and improve techniques while retraining the muscle memory in the brain. If turn-out is insufficient it can result in the use of compensatory techniques including; increased lumbar lordosis, pronation of the feet, and abduction of the forefoot. Also, weak hips can lead to faulty biomechanics and lower limb alignment. These all can put the dancer at higher risk of injury.
- A gradual return to activities: Dance-specific movements that originally aggravated the condition are also gradually reintroduced, with particular care taken to correct any underlying specific technique related problems like overpronation, maintenance of turnout at the hip, or landing mechanics in jumps.
Prevention
Considering the high incidence of injury involving the ankle and foot, prevention of injuries to this area should be a priority for dancers.
Preventive conditioning measures should involve sound training principles to avoid extreme fatigue or sudden increases in dance training by maintaining condition during layoffs or breaks, as well as performing strength, flexibility, and proprioceptive exercises.
Preventive technique considerations include using the suitable placement of the bodyweight over the axis of the foot through various techniques including the use of the stirrup muscles and maintaining sufficient turnout at the hip.
With respect to equipment considerations, careful selection of well-fitting shoes, where appropriate, well-designed transitions for the addition of pointe work in ballet dancers, and use of floors with good resiliency and friction characteristics whenever possible may also help prevent FHL injuries.
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