What Is A FHL (Flexor Hallucis Longus)Tendonopathy?
A tendonopathy effects the tendons of the body. A tendon connects muscle to bone and is a continuation of the muscle. It is therefore involved in movement with the contraction of muscles. A healthy pain free tendon is strong and has its fibres lain down to form lines of strength. (Imagine a bundle of dry spaghetti! )When a tendon, in this case the Flexor Hallucis Longus tendon, becomes injured it takes on water, swells and ends up looking more like wet spaghetti!! It therefore has little order to it and loses its strength. It may also develop a swollen lump/nodule normally found towards the bottom third of the tendon as it passes behind the ankle bone that can be painful to touch.
Causes of FHL Tendonopathy
Long-term overuse of FHL muscle can lead to thickening of the tendon. This thickening is often detected under the inside ankle bone where the tendon passes through a fibrous tunnel of tissue. Chronic misuse of the muscle can come from clawing the toe when pointing, gripping with the toes on standing and rising, or when trying to stabilise a ‘wobbly’ ankle. Chronic overuse and resulting weakening and change in structure of the tendon may be accompanied with a nodule/lump in the tendon which can get ‘stuck’ as it glides behind the ankle. In these cases, the big toe may ‘lock’ and you need to wriggle the toe to unlock it. This is called ‘trigger toe’. Before getting to this stage there may just be clicking behind the ankle as you wiggle the big toe.

Recovery

A strong foot and ankle combined with correct technique is very important in resolving this problem. Specific exercises can be given by your physiotherapist.

Recovery will depend on the level of damage. If caught early enough it may only take a couple of weeks to resolve or it may take up to 3 months. Continuous treatment and rehab will be required to guide the condition and eliminate any causative factors.
For more severe cases, surgery may be required to remove the nodule. Post surgical rest and rehab will be required in this case.