Evidence brief
Adult Acquired Flatfoot Deformity: Classification and Treatment
Stage I: Tendinitis, no deformity
Stage II: Flexible deformity (IIA/IIB based on forefoot)
Stage III: Rigid hindfoot deformity
Stage IV: Deltoid involvement, valgus tilt
Treatment escalates with stage
Johnson-Strom staging (modified by Myerson) guides treatment from conservative (Stage I) to extensive reconstructive surgery (Stage IV).
Know stages and treatment. Stage I: immobilization, orthotics. Stage IIA: medializing calcaneal osteotomy, FDL transfer. Stage IIB: add lateral column lengthening. Stage III: triple arthrodesis. Stage IV: tibiotalocalcaneal fusion. Single heel raise test critical for diagnosis.
Johnson KA, Strom DE. Tibialis posterior tendon dysfunction. Clin Orthop Relat Res. 1989;(239):196-206.
Level IV
Case series or case reports