Concept
Progressive collapsing foot deformity is a three-dimensional adult-acquired deformity involving varying combinations of:
- hindfoot valgus
- loss of medial arch
- forefoot abduction
- medial-column instability
- peritalar subluxation
- ankle valgus in advanced disease
Posterior tibial tendon dysfunction is important but does not explain the entire disorder.
Progressive collapsing foot deformity describes a spectrum historically labelled adult-acquired flatfoot or posterior tibial tendon dysfunction. The deformity is not solely a tendon rupture; it involves progressive failure of dynamic and static stabilisers of the medial arch.
Components may include:
- hindfoot valgus
- collapse of the medial arch
- forefoot abduction
- forefoot supination
- ankle valgus in advanced disease
Clinical assessment
Symptoms may begin with medial ankle pain and later shift laterally as deformity progresses.
Look for:
- hindfoot valgus
- collapsed arch
- forefoot abduction
- prominent talar head medially
- difficulty with single-leg heel rise
- Achilles/gastrocnemius tightness
- fixed versus flexible deformity
- ankle valgus or deltoid insufficiency
Imaging
Weight-bearing foot and ankle radiographs assess:
- talonavicular uncoverage
- arch collapse
- hindfoot alignment
- midfoot and ankle arthritis
Weight-bearing CT can define peritalar subluxation and three-dimensional deformity where available.
Weight-bearing radiographs should assess:
- talonavicular uncoverage
- talo-first metatarsal relationship
- hindfoot alignment
- subtalar and midfoot arthritis
- ankle valgus
MRI or ultrasound may help assess tendon and ligament pathology when the diagnosis or surgical planning requires it.
Non-operative treatment
- activity modification
- supportive footwear
- custom orthosis
- ankle-foot brace for more advanced disease
- calf stretching where appropriate
- strengthening in early flexible disease
Surgical principles
The operation should correct every important component of deformity while avoiding unnecessary fusion.
Flexible deformity may require combinations of:
- medialising calcaneal osteotomy
- lateral-column lengthening in selected forefoot abduction
- medial-column procedures
- tendon reconstruction or transfer
- gastrocnemius recession
Rigid deformity or established arthritis often requires fusion of the symptomatic/deformed joints.
Ankle involvement may require additional reconstruction when deltoid insufficiency and talar tilt are present.
Viva structure
Describe the deformity in three planes, state whether it is flexible, identify the painful/arthritic joints, and then build treatment around those findings.
Pathoanatomy
The tibialis posterior is a major dynamic stabiliser, but the spring ligament, deltoid complex, plantar fascia and medial-column joints are also important.
Once hindfoot valgus and talonavicular uncovering develop, the Achilles may act lateral to the hindfoot axis and become a deforming force.
Clinical examination
Look for:
- too-many-toes sign
- loss of medial arch
- hindfoot valgus
- swelling/tenderness along tibialis posterior
- inability or pain with single-leg heel rise
- failure of heel inversion on heel rise
- Achilles/gastrocnemius tightness
Correct the hindfoot manually and observe whether forefoot supination appears. This helps plan whether medial-column correction is needed.
Assess ankle stability because deltoid insufficiency can produce valgus tilt in advanced disease.
Non-operative management
Early or lower-demand disease may be managed with:
- weight and activity modification
- physiotherapy
- calf stretching
- orthosis or brace
- analgesia
The brace must control hindfoot and midfoot alignment, not simply support the arch cosmetically.
Reconstruction of flexible deformity
Flexible disease may require a combination of procedures rather than one operation.
Possible components:
- gastrocnemius recession/Achilles lengthening
- medialising calcaneal osteotomy
- tendon transfer
- spring-ligament reconstruction
- lateral-column procedure for marked abduction
- medial-column plantarflexion correction when forefoot supination persists
Each component should correct a documented element of deformity.
Rigid or arthritic deformity
When the deformity becomes fixed or joints are arthritic, fusion of involved joints is often more appropriate than soft-tissue reconstruction.
FRCS synthesis
The key exam concept is deformity analysis. State whether the foot is flexible, which planes are involved, whether there is ankle involvement and which static/dynamic stabilisers have failed. Then construct the operation to correct each component.