SLR - July 2019 - Emily Curley

Tibialis Posterior Transfer for Foot Drop Due to Central Causes: Long-Term Hindfoot Alignment

Reference: Sturbois-Nachef N, Allart E, Grauwin M-Y et al. Tibialis Posterior Transfer for Foot Drop Due to Central Causes: Long-Term Hindfoot Alignment. Orthopaedics & Traumatology: Surgery & Research. 2019: 105(1):153-8.

Scientific Literature Review

Reviewed By:
Emily Curley, DPM
Residency Program: Metrowest Medical Center – Framingham, MA

Podiatric Relevance: Transfer of the tibialis posterior tendon (TPTT) is a widely studied and common surgical treatment for foot drop secondary to peripheral neuropathy. However, few studies evaluate its use for foot drop caused by central neurological pathology. The goals of the study were to evaluate the impact of foot alignment and gait in patients with central foot drop after having a TPTT, specifically assessing potential of long-term flattening of the medial arch.

A retrospective study was performed at a single hospital in Lille, France. There was an evaluation of patients from 1995-2012 who underwent TPTT for drop foot due to an acquired central neurological abnormality. Inclusion and exclusion criteria were clearly defined. Thirteen patients in total were ultimately included in the retrospective review. Surgical procedures for the TPTT and adjunct procedures as deemed necessary were described as well as post-operative course. Clinical assessment methods included footprint parameters, ankle dorsiflexion in the supine position, dorsiflexory strength, and Global Assessment Scale for overall change from the TPTT. Specific radiographic measurements in all three planes were evaluated. The use of an orthopedic shoe or brace before and/or after the procedure was recorded.

A pronation deformity was identified in 15.4 percent operated feet and a supination deformity was identified in 2/13 operated feet after a TPTT. Footprint parameters revealed pes cavus deformity in 53.8 percent operated feet. No cases of flatfoot were identified on the operated side. Radiographic parameters showed significant differences in lateral arch angle and calcaneal pitch angle on the operated side; indicating propensity towards posterior pes cavus with increased lateral arch height on the operated feet. Eighty-five percent of patients were able to achieve active dorsiflexion of their operated side with an average dorsiflexion strength of 2.9/5. Fifty-four percent of patients had visible active dorsiflexion during the swing phase of gait. Ten out of thirteen patients who wore an orthosis or orthopedic shoe prior to surgery no longer required its use after surgery. No patients reported post-operative worsening.

The authors found that there were no patients who had an induced collapsed arch after TPTT for dropfoot secondary to central neurological defects, and in fact found a tendency towards pes cavus development following the procedure. Most patients found an improvement of gait following the procedure. They suggest a propensity towards pes cavus development may be spasticity of intrinsic musculature. Reported limitations included evaluation bias due to the retrospective nature of the study and the heterogeneity of their sample population. The authors point out that they are the only known study to include a filmed gait analysis on adults with central neurological abnormalities. Other limitations include the underpowered sample number. Also it is unclear as to how many different surgeons were performing the procedure at the site. There was a lack in detail between inter-rater and intra-rater reliability. Larger scale and prospective studies would be beneficial.

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