title: Comparison of transfer sites for flexor digitorum longus in a cadaveric adult acquired flatfoot model.
abstract: Posterior tibialis tendon (PTT) dysfunction (PTTD) is associated with adult acquired flatfoot deformity. PTTD is commonly treated with a flexor digitorum longus (FDL) tendon transfer (FDLTT) to the navicular (NAV), medial cuneiform (CUN), or distal residuum of the degraded PTT (rPTT). We assessed the kinetic and kinematic outcomes of these three attachment sites using cadaveric gait simulation. Three transfer locations (NAV, CUN, rPTT) were tested on seven prepared flatfoot models using a robotic gait simulator (RGS). The FDLTT procedures were simulated by pulling on the PTT with biomechanically realistic FDL forces (rPTT) or by pulling on the transected FDL tendon after fixation to the navicular or medial cuneiform (NAV and CUN, respectively). Plantar pressure and foot bone motion were quantified. Peak plantar pressure significantly decreased from the flatfoot condition at the first metatarsal (NAV) and hallux (CUN). No difference was found in the medial-lateral center of pressure. Kinematic findings showed minimal differences between flatfoot and FDLTT specimens. The three locations demonstrated only minimal differences from the flatfoot condition, with the NAV and CUN procedures resulting in decreased medial pressures. Functionally, all three surgical procedures performed similarly.
authors.affiliation: RR&D Center of Excellence for Limb Loss Prevention and Prosthetic Engineering, VA Puget Sound, Seattle, Washington, 98108; School of Medicine, University of Washington, Seattle, Washington, 98195.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Vaudreuil
authors.forename: William R
authors.initials: WR
authors.lastname: Ledoux
authors.forename: Grant C
authors.initials: GC
authors.lastname: Roush
authors.forename: Eric C
authors.initials: EC
authors.lastname: Whittaker
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Sangeorzan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology; D002102:Cadaver; D005260:Female; D005413:Flatfoot / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D037081:Posterior Tibial Tendon Dysfunction / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D011312:Pressure; D011859:Radiography; D012371:Robotics; D013639:Tarsal Bones / Q000000981:diagnostic imaging / Q000502:physiology; D013710:Tendons / Q000637:transplantation*; D016474:Weight-Bearing / Q000502:physiology
keywords: FDL; PTTD; flexor digitorum longus transfer; gait simulation; posterior tibial tendon dysfunction