Tibialis Posterior Tendon Dysfunction Stages: Johnson and Strom Classification

Tibialis posterior tendon dysfunction (PTTD) is the most common cause of adult-acquired flatfoot deformity — a progressive condition in which the posterior tibial tendon (PTT) fails, first in function and then in structural integrity, leading to collapse of the medial longitudinal arch, hindfoot valgus, and forefoot abduction. The Johnson and Strom classification (modified by Myerson) divides PTTD into four stages based on the degree of tendon involvement, deformity magnitude, reducibility, and presence of arthritic changes. Stage determines treatment: the single-heel-rise test is a fundamental bedside assessment that tracks functional deterioration across stages.

Johnson-Strom-Myerson Staging of PTTD

Stage	Tendon Status	Deformity	Single-Heel-Rise Test	Treatment
Stage I	Tendinopathy (peritendinitis, tenosynovitis, interstitial degeneration); tendon intact; normal length	No deformity; arch maintained; normal alignment; medial ankle pain and swelling	Normal — can perform multiple single-heel rises; pain may occur at end of repetitions	Medial longitudinal arch support (UCBL or custom orthotic); physical therapy (eccentric PTT strengthening); NSAIDs; immobilization boot for 4-6 weeks if acute
Stage II	Tendon elongated, attenuated, or partially torn; loss of mechanical advantage; may have areas of complete tearing	Flexible flatfoot deformity; hindfoot valgus (reducible); forefoot abduction (too many toes sign); loss of arch; still reducible manually	Absent or weak single-heel rise on affected side; cannot invert heel during rise (hallmark); may perform 1 labored rise with pain	II-A (mild): custom UCBL orthotic, Arizona brace, or AFO; PTT-specific PT; II-B (severe flexible): surgical reconstruction — FDL transfer + calcaneal osteotomy or medial slide; spring ligament repair
Stage III	Tendon dysfunctional, elongated, or absent; secondary changes in subtalar and midtarsal joints	Rigid flatfoot deformity; hindfoot valgus NOT reducible; fixed subtalar arthrosis; forefoot supination	Absent — cannot perform single-heel rise; severe weakness	Subtalar arthrodesis (isolated or double); AFO/CROW for non-surgical candidates; surgical: hindfoot fusion to correct rigid deformity
Stage IV	Same as Stage III; additional ankle (tibiotalar) involvement	Rigid flatfoot + valgus tilt of talus within ankle mortise; tibiotalar arthrosis; ankle instability	Absent	Triple arthrodesis + tibiotalar arthrodesis or total ankle replacement; highly complex reconstruction; significant complication rate

Diagnostic Tests and Clinical Findings by Stage

Test / Finding	Stage I	Stage II	Stage III-IV
Single-heel-rise test	Intact (multiple rises possible)	Absent or weak; heel does not invert	Absent
Too-many-toes sign	Absent	Present (2+ toes visible lateral to heel from behind)	Present and fixed
Subtalar motion	Normal	Full, reducible inversion	Reduced or absent; rigid
MRI findings	Peritendinous fluid; interstitial tears; tendon enlargement; signal change	Partial or complete tear; tendon attenuation; spring ligament laxity or tear	Tendon absent or non-functional; secondary joint arthrosis
Weight-bearing X-ray	Normal	Decreased calcaneal pitch; increased talar-first metatarsal angle; talar head uncoverage	Fixed deformity; subtalar arthrosis; possible tibiotalar involvement (Stage IV)
Tendon palpation	Medial ankle tenderness along tendon; swelling in retromalleolar groove	Defect or thickening palpable; weakness on manual testing	Absent tendon bulk; severe weakness

At Balance Foot & Ankle in Howell and Bloomfield Hills, PTTD is staged with weight-bearing X-rays, single-heel-rise testing, and MRI of the tendon — Stage I-IIA patients are successfully treated with custom bracing and physical therapy, while Stage IIB patients are offered tendon reconstruction with FDL transfer before the deformity becomes fixed. Call (810) 206-1402.

For a complete clinical overview: Ankle Pain Conditions Guide — location-by-location ankle pain diagnosis and treatment