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Bones & Joints
Posterior tibial tendon dysfunction (PTTD) is progressive weakening and degeneration of the posterior tibial tendon—the main tendon supporting the arch of the foot—leading to adult-acquired flatfoot deformity, most commonly affecting middle-aged and older women (particularly those with obesity, diabetes, or hypertension). The condition develops when the posterior tibial tendon (running behind inside ankle bone down to midfoot bones) gradually stretches, tears, and fails, causing the foot arch to collapse, the heel to tilt outward (valgus), and the forefoot to turn outward (abduction)—creating a characteristic 'too many toes' sign when viewing foot from behind. PTTD progresses through four stages: Stage I (tendinitis with pain but no deformity), Stage II (flexible flatfoot deformity that can be passively corrected), Stage III (fixed rigid flatfoot that cannot be corrected), and Stage IV (ankle arthritis from altered biomechanics). Patients present with progressive medial ankle and arch pain, difficulty walking on uneven ground, inability to stand on tiptoes on affected foot (single heel raise test), and worsening foot shape over months to years. Treatment is stage-dependent: Stage I managed conservatively with immobilization, orthotics, physiotherapy (80-90% success); Stage II requires orthotic trial but often needs surgical tendon reconstruction and bone realignment procedures (85-90% success with surgery); Stages III-IV require major reconstructive surgery (joint fusions) with 70-80% achieving stable, functional (though stiff) foot. Untreated PTTD progresses inexorably to severe fixed deformity, chronic pain, and disability.
What it is and why it happens
Posterior tibial tendon dysfunction (PTTD) is progressive weakening and degeneration of the posterior tibial tendon—the main tendon supporting the arch of the foot—leading to adult-acquired flatfoot deformity, most commonly affecting middle-aged and older women (particularly those with obesity, diabetes, or hypertension). The condition develops when the posterior tibial tendon (running behind inside ankle bone down to midfoot bones) gradually stretches, tears, and fails, causing the foot arch to collapse, the heel to tilt outward (valgus), and the forefoot to turn outward (abduction)—creating a characteristic 'too many toes' sign when viewing foot from behind. PTTD progresses through four stages: Stage I (tendinitis with pain but no deformity), Stage II (flexible flatfoot deformity that can be passively corrected), Stage III (fixed rigid flatfoot that cannot be corrected), and Stage IV (ankle arthritis from altered biomechanics). Patients present with progressive medial ankle and arch pain, difficulty walking on uneven ground, inability to stand on tiptoes on affected foot (single heel raise test), and worsening foot shape over months to years. Treatment is stage-dependent: Stage I managed conservatively with immobilization, orthotics, physiotherapy (80-90% success); Stage II requires orthotic trial but often needs surgical tendon reconstruction and bone realignment procedures (85-90% success with surgery); Stages III-IV require major reconstructive surgery (joint fusions) with 70-80% achieving stable, functional (though stiff) foot. Untreated PTTD progresses inexorably to severe fixed deformity, chronic pain, and disability.