summary Posterior Tibial Tendon Insufficiency is the most common cause of adult-acquired flatfoot deformity, caused by attenuation and tenosynovitis of the posterior tibial tendon leading to medial arch collapse. Diagnosis can be made clinically with loss of medial arch of the foot which may progress to hindfoot valgus, forefoot abduction and subsequent development of midfoot osteoarthritis. Treatment is nonoperative with orthotics and ankle braces in early stages. A variety of surgical options are available and indicated for progressive and rigid deformities, subtalar or midfoot arthritis, and failure of nonoperative management. Epidemiology Demographics more common in women often presents in the sixth decade Risk factors obesity hypertension diabetes increased age corticosteroid use seronegative inflammatory disorders Etiology Mechanism exact etiology is unknown acute injury (e.g., ankle fractures caused by pronation and external rotation) vs. long-standing tendon degeneration Pathoanatomy early disease early tenosynovitis progresses to PTTI login to view 1 more bullet late disease PTTI contributes to attritional failure of static hindfoot stabilizers and collapse of the medial longitudinal arch login to view 3 more bullets fixed degenerative joint changes occur at late stages foot deformity pes planus hindfoot valgus forefoot varus forefoot abduction Associated conditions inflammatory arthropathy tarsal coalition young person with rigid pes planus and/or recurrent ankle sprains Anatomy Muscle tibialis posterior originates from posterior fibula, tibia, and interosseous membrane innervated by tibial nerve (L4-5) Tendon posterior tibial tendon (PTT) lies posterior to the medial malleolus before dividing into 3 limbs anterior limb login to view 1 more bullet middle limb login to view 1 more bullet posterior limb login to view 1 more bullet Blood supply branches of the posterior tibial artery supply the tendon distally a watershed area of poor intrinsic blood supply exists between the navicular and distal medial malleolus (2-6 cm proximal to navicular insertion) Biomechanics PTT lies in an axis posterior to the tibiotalar joint and medial to the axis of the subtalar joint functions as a primary dynamic support for the arch acts as a hindfoot invertor adducts and supinates the forefoot during stance phase of gait acts as secondary plantar flexor of the ankle major antagonist to PTT is peroneus brevis activation of PTT allows locking of the transverse tarsal joints creating a rigid lever arm for the toe-off phase of gait Classification Posterior Tibial Tendon Insufficiency Classification Deformity Physical exam Radiographs Stage I Tenosynovitis No deformity (+) single-heel raise Normal Stage IIA Flatfoot deformity Flexible hindfoot Normal forefoot (-) single-leg heel raise Mild sinus tarsi pain Arch collapse deformity Stage IIB Flatfoot deformity Flexible hindfoot Flexible forefoot abduction ("too many toes", > 40% talonavicular uncoverage) (-) single-leg heel raise Mild sinus tarsi pain Arch collapse deformity Stage IIC Flatfoot deformity Flexible hindfoot Rigid forefoot abduction (-) single-leg heel raise Moderate sinus tarsi pain Arch collapse deformity Gapping of 1st TMT joint Stage III Flatfoot deformity Rigid hindfoot valgus Rigid forefoot abduction (-) single-leg heel raise Severe sinus tarsi pain Arch collapse deformity Subtalar arthritis Stage IV Flatfoot deformity Rigid hindfoot valgus Rigid forefoot abduction Deltoid ligament compromise (-) single-leg heel raise Severe sinus tarsi pain Ankle pain Arch collapse deformity Subtalar arthritis Talar tilt in ankle mortise Presentation Symptoms medial ankle/foot pain and weakness is seen early progressive loss of arch lateral ankle pain due to subfibular impingement is a late symptom Physical exam inspection & palpation pes planus login to view 1 more bullet hindfoot valgus deformity login to view 2 more bullets forefoot abduction (Stage IIB disease) login to view 2 more bullets forefoot varus login to view 4 more bullets tenderness just posterior to tip of medial malleolus login to view 1 more bullet equinus contracture login to view 1 more bullet range of motion single-limb heel rise login to view 1 more bullet PTT power login to view 2 more bullets determine whether deformity is flexible or fixed login to view 2 more bullets Imaging Radiographs recommended views weight bearing AP and lateral foot ankle mortise findings AP foot login to view 3 more bullets weight bearing lateral foot login to view 10 more bullets ankle mortise login to view 2 more bullets MRI findings variable amounts of tendon degeneration and arthritic changes in the talonavicular, subtalar, and tibiotalar joints Ultrasound increasing role in the evaluation of pathology within the PTT Differential Pes planus secondary to midfoot pathology (osteoarthritis or chronic Lisfranc injury) treat with midfoot fusion and a realignment procedure incompetence of the spring ligament (primary static stabilizer of the talonavicular joint) in the absence of PTT pathology treat with adjunctive spring ligament reconstruction in addition to standard flatfoot reconstruction Treatment Nonoperative ankle foot orthosis indications login to view 2 more bullets technique login to view 4 more bullets immobilization in walking cast/boot for 3-4 months indications login to view 1 more bullet custom-molded in-shoe orthosis indications login to view 2 more bullets technique login to view 3 more bullets Operative tenosynovectomy indications login to view 1 more bullet FDL transfer, calcaneal osteotomy, TAL, ± forefoot correction osteotomy ± spring ligament repair ± lateral column lengthening ± medial column arthrodesis ± PTT debridement indications login to view 3 more bullets contraindications login to view 5 more bullets first TMT joint arthrodesis, calcaneal osteotomy, TAL ± lateral column lengthening ± PTT debridement indications login to view 1 more bullet isolated subtalar arthrodesis indications login to view 1 more bullet contraindications login to view 3 more bullets hindfoot arthrodesis indications login to view 5 more bullets triple arthrodesis and TAL + deltoid ligament reconstruction indications login to view 1 more bullet tibiotalocalcaneal arthrodesis indications login to view 1 more bullet Techniques FDL transfer indications FDL is synergistic with tibialis posterior and therefore transfer can augment function of deficient PT Stage II disease relative contraindications rigidity of subtalar joint (<15 degrees of motion) fixed forefoot varus deformity (>10-12 degrees) technique find FDL and FHL at knot of Henry insert FDL into navicular near insertion of PT vs. FHL transfer login to view 2 more bullets Calcaneal osteotomy indicated to correct hindfoot valgus techniques include medial displacement calcaneal osteotomy (MDCO) login to view 1 more bullet Evans lateral column lengthening osteotomy login to view 4 more bullets can be performed open or through a minimally invasive approach minimally invasive techniques associated with fewer wound complications, lower rates of nerve injury, decreased radiation exposure and shorter operative times TAL or gastrocnemius recession indicated for equinus contracture Forefoot correction osteotomy indicated for fixed forefoot supination/varus (stage IIC) techniques plantarflexion (dorsal opening-wedge) medial cuneiform (Cotton) osteotomy login to view 2 more bullets medial column fusion (isolated first TMT fusion, isolated navicular fusion, or combined TMT and navicular fusions) login to view 1 more bullet Spring ligament repair indicated with spring ligament rupture in some cases PTT debridement may also be required Triple arthrodesis triple arthrodesis includes calcaneocuboid, talonavicular, subtalar joints additional medial column stabilization may be required