If you know a dancer, then you may have heard them complaining about medial ankle pain or pain on the bottom of the foot (often due to an injury to the flexor hallucis longus (FHL) muscle). Injury to the FHL muscle is also known as “Dancer’s Tendonitis”, but don’t let that name fool you because this injury is not limited to just dancers. This injury commonly affects runners, soccer players, and any other athlete who performs repeated, propulsive activities, such as jumping.

The Flexor Hallucis Longus

The flexor hallucis longus muscle (FHL - shown in red) runs deep to your calf muscles (gastrocnemius and soleus). Injury to the FHL is a somewhat elusive condition which is often overlooked or misdiagnosed. FHL injury often manifests in two forms, either as inflammation (tendonitis), or as a tear in the tendon of the FHL muscle.

SPECIAL CONSIDERATIONS FOR DANCERS

In dancers, injury to the FHL is often caused by the repetitive motion 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 describes the action when a dancer rises up on their toes). This action produces a force that is 10 times the dancer’s body weight. Ballet dancers with FHL tendonitis may also feel pain when going from demi-pointe to full pointe. (Demi-pointe position in ballet in is when the dancer is on the balls of their feet, also called half-point. Full Point (en pointe) is when the dancer has a fully extended vertical foot).

For a dancer, any action that causes a reduction in plantar flexion (pointing the toes down) motion can result in an FHL injury. Bio-mechanically, a lack of plantar flexion can lead to a prolonged pronation position of the foot when pushing off during the Propulsion Phase.

In dancers, the FHL tendon is often compressed while performing a relevé position and is over-stretched while performing a plié position. In such a case, the dancer will feel posterior medial ankle pain when performing the plié.

CAUSES AND PRESENTATIONS OF MEDIAL ANKLE PAIN

The repetitive motion of pushing-off with your foot (plantar flexion) during dance, running, or any other sport that involves jumping, can cause injury to the FHL.

Injury to the FHL tendon and muscle can present in a variety of ways, sometimes involving inflammation. Injury to the tendon without inflammation is referred to as “Tendinopathy”. Tendinopathy refers to a degenerative lesion in the tendon that does not affect the tendon sheath that surrounds the tendon.

In contrast, when FHL inflammation (Tendonitis) is present in the foot, it usually occurs in one of the following three locations.

• Along the inside of the ankle (fibro-osseous tunnel along the posteromedial ankle).

• At the “Knot of Henry” – a section just behind the big toe (first metatarsal) where the FDL (flexor digitorum longus) muscle crosses the FHL (flexor hallicus longus) tendon.

• Just behind the big toe by the sesamoid bone. A sesamoid bone increases mechanical force by holding a tendon away from the center of the joint.

ANATOMY BIO-MECHANICS OF THE FHL

Let’s take a look at the flexor hallicus longus (FHL) muscle and its relationship to surrounding structures. The FHL muscle helps you to point your big toe (plantar-flexing your big toe) and also helps to stabilize the subtalar joint (talocalcaneal joint).

The subtalar joint is located between two bones in your ankle, the talus and the calcaneus. The subtalar joint allows movement of the heel toward the medial plane (inversion) as well as movement of the heel towards the lateral plane (eversion).

About the FHL

The flexor hallucis longus (FHL) muscle is located deep under your calf muscles (the most lateral muscle of the deep compartment).

The flexor hallucis longus originates on the lateral lower leg (distal 2/3 of the fibula). It then travels at an oblique angle (crosses the posterior surface of tibia) down towards the medial ankle (posterior surface of talus) and travels under a section of the heel bone (sustentaculum tali of calcaneus).

The FHL then passes under the sole of the foot (between the two heads of the flexor hallucis brevis) and inserts into the base of the big toe (base of the distal phalanx of hallux).

As the FHL passes through the medial ankle it also passes through a structure known as the tarsal tunnel. The tarsal tunnel is formed by the a thick ligament, two ankle bones and a muscle (flexor retinaculum, calcaneus, talus, and the abductor muscle).

In addition to the FHL, there are two other tendons (flexor digitorum longus, tibialis posterior), the tibial nerve, and the posterior tibial artery that also pass through the tarsal tunnel. Restrictions or inflammation of any of these structures can cause functional changes in gait patterns, nerve entrapment, or vascular dysfunction (Tarsal Tunnel Syndrome).

Big Toe Trigger Finger

When the FHL tendon becomes nodular, a condition called Hallux Saltans can develop. Hallux Saltans is similar to trigger finger in the hand, except it occurs in the big toe. Triggering of the toe occurs when the nodular thickening of the tendon snaps through the fibro-osseous tunnel. This causes a jerking motion, much like a trigger finger.

If not addressed Hallux Saltans can contribute to the progression of an additional condition called Hallux Rigidus. Hallux Rigidus means "stiff great toe". Hallux Rigidus is the second most common disorder of the big toe joint (first MTP joint). (The most common injury is a bunion otherwise known as Hallux Valgus.)

Diagnosis and Imaging for FHL Injuries

X-Rays will not provide a definitive diagnosis for an FHL injuries. However, X-Rays are good for ruling out fractures that may cause an impingement of the FHL tendon.

A comprehensive patient history, accompanied by a full physical examination is often critical for properly diagnosing this condition. On the other hand, in certain cases when imaging is required to determine tissue damage, MRI imaging is your best choice, but ultrasound imaging may also be effective (and much cheaper). The following videos demonstrate procedures that we commonly use in the examination of an Achilles injury.

Effective Ankle and Foot Examination

This video uses orthopaedic test to evaluate for some of the most common ankle and foot conditions we see in clinical practice. These conditions include: Ankle Sprains (inversion sprain), Cuboid Syndrome, Talar Dome Lesions, 5th Metatarsal Fracture, Syndesmosis damage, Achilles Tendon Tendinopathy, Morton's Neuroma, 2nd Metatarsal Stress Fracture, Plantar Fasciitis, and Bunions. This video is available for the public Jan 6/2023.

Lower Limb Neuro Examination

The lower limb neurological examination is part of the over all neurological examination process, and is used to assess the motor and sensory neurons which supply the lower limbs. This assessment helps to detect any impairment of the nervous system. It is used both as a screening and an investigative tool. This video is available for the public on Nov 11/2022.

Peripheral Vascular Examination - Key Points

A peripheral vascular examination is a valuable tool used for ruling out signs of vascular-related pathology. The detection and subsequent treatment of PVD can potentially mitigate cardiovascular and cerebrovascular complications. In this video we go over some of the common procedures we perform in daily clinical practice. This video is available for the public on November 14/2022.

RECOMMENDED ORTHOPAEDIC REFERENCE BOOKS

Orthopaedic Physical Assessment – David J. Magee https://amzn.to/3zgu0za

Dutton'sOrthopaedic: Examination, Evaluation and Intervention, Fifth Edition https://amzn.to/3st1AOv

Treatment of Dancer’s Tendonitis

In most cases, Dancer’s Tendonitis (involving partial FHL tears, tendinosis, or other inflammatory conditions) responds well to Conservative Care. Conservative Care is non-surgical, and works largely on the soft-tissue and joints, and is often the most effective treatment for resolving these injuries. Manual therapy, combined with a functional exercise program are particularly powerful and effective for reaching a full resolution. You can expect at least four to six weeks of conservative care for full recovery. Often, full activities cannot be resumed until the pain symptoms have completely subsided.

Even after the pain has subsided, I recommend a slow return to activities. In the case of dancers this could mean initially leaving out point work, jumps or grand plies (a grand plié requires a full knee bend).

Conservative Care for Dancers Tendonitis

• Ice massages are beneficial during the initial stage to reduce inflammation. Then heat to increase circulatory function.

• Reduction in activity. Usually, some modification of all activities is necessary to promote healing.

• Supports (crutches or walker boot) can sometimes be beneficial (in the short term).

• Taping of the foot and ankle.

• Soft-tissue therapy and joint mobilization is critical for rapid, long-term recovery. This includes considering and treating both Local Tensegrities (local structures) and Global Tensegrities (structures in the larger kinetic chain).

• Carefully selected exercises that support the development of strength, flexibility and balance. Remember success in resolving this condition will be dictated by the patient’s compliance with exercise protocols.

• A gradual return to activities.

• Following appropriate anti-inflammatory recommendations (nutritional, dietary, and possible pharmaceutical recommendations from your medical doctor). We often recommend concurrent treatments, working with a multidisciplinary team.

The following three videos demonstrate the type of protocols we would use to release the FHL, but all related muscles and joint restrictions in the foot and ankle.

MSR Calf Muscle + Tom, Dick, and Harry Release: This video is about releasing both your superficial calf muscles (gastrocnemius and soleus) and the deeper muscles Tom, Dick, and Harry (TDH). Tom, Dick, and Harry stands for: T=Tibialis posterior, D=Flexor digitorum longus, an=posterior tibial artery and tibial nerve, and H=Flexor hallucis longus.

4 Point Dorsi Flexion Protocol - Motion Specific Release: Dorsiflexion is the movement at the ankle joint where the toes are brought closer to the shin. The muscles of the shins help your foot to clear the ground during the Swing Phase (concentric contraction) of your stride, and absorb much of the impact shock during running.

MSR - 7 Point Ankle & Foot Mobilization: Improving joint mobility is critical if you are going to effectively address the body's full kinetic chain. In fact, we greatly reduce the effectiveness of any myofascial treatment if we don’t also address the restrictions in joint mobility. The objective of joint mobilization is to reverse adverse physiological changes by promoting movement between capsular fibers.

RECOMMENDED REFERENCE BOOKS

Netter Atlas of Human Anatomy https://amzn.to/3SQYWgx

Functional Atlas of the Human Fascial System - Carla Stecco https://amzn.to/3TE1EqP Functional Anatomy: Anatomy, Kinesiology, and Palpation https://amzn.to/3f49Xgn

Joint mobilization/manipulation extremity and spinal techniques https://amzn.to/3DxqCCs

The Trigger Point Manual - https://amzn.to/3gFDDRu

Chinese Acupuncture and Moxibustion (4th Edition) - https://amzn.to/3TRDs3M

Prognosis & Prevention of Dancer’s Tendonitis

Fortunately, most patients with an FHL injury can recover completely with the correct soft-tissue therapy and appropriate exercise program. It is important is to initiate soft tissue (MSR) therapy as soon as possible. In my experience, these treatments will greatly speed the recovery process of an FHL injury.

So, how can you prevent an FHL injury from occurring?

You will need to find a balance between flexibility and strength within all the structures that surround the ankle. In addition to being diligent with your flexibility and strengthening exercises, a program of ongoing maintenance care that addresses early signs of stress can greatly help in preventing FHL injuries from occurring.

DR. BRIAN ABELSON DC.

Dr. Abelson believes in running an Evidence Based Practice (EBP). EBP's strive to adhere to the best research evidence available, while combining their clinical expertise with the specific values of each patient.

Dr. Abelson is the developer of Motion Specific Release (MSR) Treatment Systems. His clinical practice in is located in Calgary, Alberta (Kinetic Health). He has recently authored his 10th publication which will be available later this year.

Make Your Appointment Today!

Make an appointment with our incredible team at Kinetic Health in NW Calgary, Alberta. Call Kinetic Health at 403-241-3772 to make an appointment today, or just click the MSR logo to right. We look forward to seeing you!

REFERENCES

1. Femino JE, Trepman E, Chisholm K, Razzano L. The role of the flexor hallucis longus and peroneus longus in the stabilization of the ballet foot. J Dance Med Sci. 2000;4(3):86–89.

2. Hamilton WG. Posterior ankle pain in dancers. Clin Sports Med. 2008;27:263–277.

3. Hodgkins CW, Kennedy JG, O’Loughlin PF. Tendon injuries in dance. Clin Sports Med. 2008;27:279–288.

4. Luk P, Thordarson D, Charlton T. Evaluation and management of posterior ankle pain in dancers. J Dance Med Sci. 2013;17(79):79–83.

5. Russell JA, McEwan IM, Koutedakis Y, Wyon MA. Clinical anatomy and biomechanics of the ankle in dance. J Dance Med Sci. 2008;12(3):75–82.

6. Sammarco GJ, Cooper PS. Flexor hallucis longus tendon injury in dancers and non-dancers. Foot Ankle Int. 1998;19(6):356–362.

7. Shutterstock images (Standard Image License): 374796559, 781706839, 129804617, 121704169, 656540218, 592652099, 376890541, 596496308, 228631444

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