Complex clinical cases around FHL: ankle, foot and knee
Through several clinical cases, Dr. Vallotton discusses the effects of flexor hallucis longus (FHL) release on complex foot and knee pain. These stories illustrate the importance of a comprehensive patient assessment to avoid more complex surgeries. FHL release is often sufficient to restore function and stability.
Doctors
Topics
Treatments
Advice
- Dr Jacques Vallotton
- FHL clinical cases
- Ankle and knee
- FHL Release
- Osteotomy
- Long-term results
- Release of the FHL
- Derotation osteotomy
- Always assess the entire lower limb
- FHL release may be enough
- Importance of clinical assessment
- Positive decline at 3 years
Complex foot-knee pain: consider FHL before heavy movements
Some foot and knee pain is caused by a biomechanical chain of events in which the flexor hallucis longus (FHL) plays a subtle but decisive role. A gliding brake at the tunnel can amplify late pronation, disrupt stability, and maintain distant pain. In selected situations, releasing the FHL is sufficient to restore function and avoid more invasive surgeries.
This perspective is part of a global evaluation of the lower limb, where we integrate morphotype, bone torsions and gait control.
Selected case: Lisfranc pain relieved by FHL release
In a patient with documented Lisfranc arthritis, chronic pain resolved after release of the FHL, without resorting to the planned arthrodesis. The lasting result suggests that, in some profiles, tendon constraint was a major permissive factor in the symptomatology.
The lesson is twofold: prioritize the causes and validate the functional response before escalating to definitive joint surgery.
Sometimes it's worth thinking about it before considering arthrodesis.
Femoral torsions and instabilities: articulation of decisions
Femoral torsion disorders can result in knee and ankle instabilities, with atypical gait adaptations. Management sometimes combines FHL release and, when the axis requires it, derotation osteotomy, depending on clinical analysis and axial imaging.
The operative timeline is decided on a case-by-case basis. The goal remains biomechanical consistency: freeing what is blocking the glide, correcting what is deviating the axis.
Young athletes with diffuse pain: identifying the right indicator
In active young adults, lateral leg pain, a positive stretch test, and reassuring imaging may indicate FHL impingement. When the indication is precisely established, tendon release provides rapid relief and allows for a gradual return to activity.
Medium-term follow-up shows normalization of support and disappearance of initial pain, without adverse changes in the posterior chain.
The fact that his tendon is sliding well is a good post-operative sign.
Keystone: clinical examination, gait and correlated imaging
Success depends on the alignment of indices: reproducible clinical testing, gait analysis objectifying terminal pronation, and axial slices assessing torsion. This triangulation limits unnecessary movements and focuses therapeutic effort on the primary cause.
The graduated approach avoids over-treatment and favors targeted solutions to serve the function.
Functional perspective: restoring glide to stabilize the chain
FHL release illustrates a rational conservative strategy: a limited gesture capable of global impact when it corrects a local lock. Stabilizing the foot relieves the knee and secures propulsion, with benefits felt in daily and sporting activities.
In practice, priority is given to a complete examination, listening to the stress profile and choosing the most proportionate solution.
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