Cavus foot (Pes cavus)

Quick overview

• Definition: Excessive longitudinal arch of the foot with increased load on the heel and forefoot
• Typical complaints: ball and heel pain, calluses, claw toes, instability/knuckling
• Frequency: may be congenital, acquired or neurological
• Diagnostics: clinical examination while standing and walking, functional and stability tests, X-ray while standing
• Therapy is initially conservative: insoles, shoe advice, physiotherapy, stretching and strengthening exercises, ankle joint stabilization
• Surgery: only if symptoms persist, severe misalignment or instability despite conservative measures

Anatomy and mechanics of the hollow foot

In a healthy foot, the longitudinal arch of the foot distributes the load evenly. In the hollow foot, this arch is greatly increased. The heel is often slightly inward (varus), the forefoot is often tilted downwards (plantar flexion of individual rays), which can lead to claw toes. The interaction of the plantar fascia, calf muscles/Achilles tendon, peroneal muscles and tibialis posterior is disrupted.

• Main load points: heel bone (calcaneus) and metatarsal head
• Forefoot overload: increased pressure under the metatarsal heads (metatarsalgia)
• Ankle joint: increased tendency to supination with a tendency to twist the ankle
• Soft tissue: often shortened calf muscles and tense plantar fascia

Typical symptoms

• Pain under the forefoot (ball) or heel, sometimes both
• Pressure points, calluses, corns on the balls of the feet and toes
• Claw toes, constriction in the shoe, painful friction on the upper leather of the shoe
• Ankle instability, frequent twisting (especially on uneven surfaces)
• Morning stiffness, plantar fascia pulling pain, shortened calf/Achilles tendon
• Pain when walking/running; Improvement in well-cushioned shoes

If left untreated, secondary problems can develop, such as irritation of the bursa, stress reactions in the midfoot or discomfort in the outer ankle area. Early, targeted treatment can often reduce subsequent symptoms.

Causes and forms

Cavus foot can occur idiopathically (with no apparent cause), congenitally, after injury or neurologically. Neurological causes (e.g. hereditary sensorimotor neuropathies such as Charcot-Marie-Tooth) lead to muscular imbalances with elevation of the arch of the foot. Prolonged instability or malhealing after ankle injuries can also promote a cavovar pattern.

• Idiopathic: Familial accumulation possible, often bilateral
• Neurological: muscle imbalance with weakness of the dorsiflexors/evertors; It makes sense to clarify if there is suspicion
• Post-traumatic: after ligament injuries, fractures or malunion
• Structurally flexible vs. rigid: flexible forms respond better to insoles/physiotherapy

Warning signs of a neurological cause can be progressive muscle weakness, sensory disorders, frequent stumbling or clearly asymmetrical findings. In such cases, we will arrange for a specialist neurological assessment if necessary.

Diagnostics in our practice

Diagnostics combines clinical experience with imaging procedures. What is crucial is the observation while stationary and in motion as well as functional tests.

• History: history of pain, twisting events, sporting/occupational stress, family history
• Inspection/statics: foot axis, toe position, callus pattern, leg length and muscle status
• Functional and stability tests: among others. Testing the evertors, calf shortening, simple block tests to assess the hindfoot and forefoot parts
• Gait and shoe analysis: rolling pattern, sole wear
• X-ray while standing: axes, height of the arch, joint condition
• For special questions: ultrasound/soft tissue, pedobarographic pressure measurement or referral for neurological diagnostics

The aim is to distinguish flexible from rigid components and to identify structures relevant to load. We base our therapy planning on this.

Conservative treatment – ​​the standard

The vast majority of patients benefit from conservative measures. These aim to distribute pressure, reduce overload, balance the muscles and improve stability.

• Individual insoles for pressure redistribution (see details below)
• Shoe advice: sufficient space in the forefoot, firm heel cap, cushioning/roll aid
• Physiotherapy: stretching (calf/Achilles tendon, plantar fascia), strengthening the dorsiflexors/evertors, sensorimotor training
• Taping/ankle bandages for instability, especially a. in the sports phase
• Skin care, pressure protection and, if necessary, toe splints for painful claw toes
• Stress control in everyday life and sport, gradual increase instead of sudden increases

Structured conservative therapy lasting several weeks is usually the first and most important step. We accompany you with clear exercise and everyday recommendations.

Insoles, shoes and orthoses

Insoles are a central instrument for hollow feet. They are intended to take the load off overstressed areas and calm the axis of the foot. The exact design depends on the individual statics.

• Pressure relief for the forefoot: soft support with metatarsal padding to relieve the pressure on the metatarsal heads
• Lateral guidance: moderate outer edge elevation (posting) to reduce the tendency to supination, if clinically appropriate
• Heel guide: well-fitting heel cup for axis stabilization
• Material: Combination of supportive and cushioning elements, depending on activity and footwear
• Shoes: enough volume in the forefoot, firm heel cap, non-slip sole; If necessary, rocker sole (rolling aid) for smoother rolling
• Sport: stable running shoes with lateral guidance and cushioning; In sports with a risk of twisting an ankle, additional ankle support

If there is severe instability in the ankle joint, functional orthoses or tapes can be used temporarily, especially during sporting activities.

Physiotherapy and your own exercises

Regular exercise improves mobility and neuromuscular control. The dosage should be adjusted to the pain and condition of the day.

• Calf/Achilles tendon stretch: 2-3 times daily, hold for 30-45 seconds (knees straightened and bent)
• Mobilize the plantar fascia: sole of foot over fascia ball/roller, 1-2 minutes, then gently stretch
• Strengthen Evertors: Pull the resistance band outwards (peroneus training), 3 sets of 12-15 repetitions
• Proprioception: standing on one leg on an unstable surface; Progress with eyes closed/rotations
• Arch training: Short kick/towel curl for the intrinsic foot muscles, slowly and controlled

Your physiotherapy accompanies the technique and progression. If the symptoms increase, take a break and have the exercise dosage checked.

Pain management and everyday adjustments

Acute irritations can often be calmed by short-term relief, cooling (10-15 minutes, with a cloth) and appropriate cushioning in the shoes. Nonsteroidal anti-inflammatory drugs (NSAIDs) may be considered in the short term, provided there are no contraindications and after medical consultation.

• Stress control: Avoid stimulus peaks, gradually increase volumes
• Shoe rotation: Alternating between well-cushioned, stable pairs
• Pressure protection: silicone pads/toe caps for irritated areas
• Taping/ankle bandage during periods of increased activity for stabilization

Targeted infiltrations (e.g. on irritated bursa or tendon attachments) are only considered in selected situations. Benefits and risks are weighed individually; they do not replace active therapy.

Regenerative and interventional options

Regenerative procedures such as platelet-rich plasma (PRP) are occasionally discussed in the event of accompanying tendon or fascia irritation. They are not causally effective for hollow foot as a form disorder. In the case of therapy-resistant, clearly defined partial problems, such an option can be considered in individual cases. The evidence is mixed; A serious explanation of the benefits, limitations and possible risks takes place before each use.

Surgery – when does it make sense?

Surgery is considered if, despite consistent conservative therapy, there is persistent pain, repeated twisting events or a pronounced, rigid misalignment that significantly restricts everyday life. The aim is to improve load distribution and restore stability.

• Soft tissue interventions: Lengthening of shortened structures (e.g. Achilles tendon/calf muscle), correction of painful claw toes
• Tendon interventions: repositioning to improve muscular balance (individually dependent on findings)
• Bone corrections (osteotomies): Correction of the forefoot and/or rear foot position to straighten the axis
• Stabilization in case of ankle ligament insufficiency, if necessary

The follow-up treatment requires patience: often immobilization and partial weight-bearing over several weeks followed by physiotherapy. The decision is always individual and is discussed calmly - without promises of healing.

Course, prognosis and possible accompanying problems

The hollow foot is a form variant that can persist due to genetic factors. Many affected people achieve a significant reduction in symptoms with conservative therapy and can cope with everyday life and sports well. A realistic goal is important: pain reduction, better resilience and fewer sprains.

• Possible subsequent problems if symptoms are untreated: recurring ankle joint sprains, metatarsalgia, irritation of the plantar fascia, arthritic changes in the metatarsal/ankle joint
• Regular checking of the insoles and adjustment to changes in activity is recommended
• Early intervention for new symptoms often prevents chronicity

Hollow foot in children and adolescents

There is a wide range of foot shape during growth. Hollow foot can run in families. Complaints, shoe restrictions or functional abnormalities are crucial. In the case of progressive misalignments or suspected neurological causes, early clarification makes sense.

• Conservative first: child-friendly insoles, exercise programs, coordination training
• Shoes with enough space and a firm heel cap; If necessary, temporarily adjust your choice of sport
• Surgery only if the course is rigid, there are significant symptoms or loss of function and after careful indication

Everyday life, work and sport

Many activities are possible with arched feet if the load and stability are controlled wisely. Suitable footwear, insoles and a stable ankle are important.

• For long standing/walking: cushioning, stable shoes, if necessary rolling aid
• Lacing technology: tight on the heel, more space in the forefoot (e.g. window lacing) to relieve toe strain
• Starting sport: build up slowly, integrate proprioceptive training into every unit
• Twist prevention: balance training, bandages in high-risk sports (e.g. trail running, ball sports)

Listen to your body’s warning signals. A short-term reduction in intensity and returning with better stability is often more effective than persisting through pain.

Prevention of complaints

• Regular stretching of the calf muscles and mobilization of the sole of the foot
• Strengthening the evertors and intrinsic foot muscles
• Shoe check: replace in time, sufficient cushioning and stability
• Check insoles regularly and adjust for changes in activity
• Slow increase in load with new sports or more intensive training plans

When should you see a doctor?

• Severe or persistent foot pain despite protection and suitable footwear
• Repeated twisting or feeling of instability
• Numbness, muscle weakness or increasing misalignment of the foot
• Open areas, inflammation, pressure points that are difficult to control
• In children/adolescents: rapid change in the shape of the foot, significant asymmetry or symptoms that affect the gait

A timely clarification helps to provide targeted treatment and avoid consequential damage.

Your visit to Hamburg

In our practice at Dorotheenstrasse 48, 22301 Hamburg, you will receive a comprehensive examination, an understandable classification of your findings and an individual therapy plan. Conservative measures are at the forefront; We only discuss surgical options if they are clearly necessary and after careful explanation.