Foot & Ankle International - July 2018 - 843

760845
research-article2018

FAIXXX10.1177/1071100718760845Foot & Ankle InternationalWagner et al

Article

Biomechanical Evaluation of Circumtibial
and Transmembranous Routes for Posterior
Tibial Tendon Transfer for Dropfoot

Foot & Ankle International®
2018, Vol. 39(7) 843-849
© The Author(s) 2018
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https://doi.org/10.1177/1071100718760845
DOI: 10.1177/1071100718760845
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Emilio Wagner, MD1, Pablo Wagner, MD1,2 , Diego Zanolli, MD1,2,
Rubén Radkievich, MD1, Gunther Redenz, PT3, and Rodrigo Guzman, PT3

Abstract
Background: Tibialis posterior tendon transfer is performed when loss of dorsiflexion has to be compensated. We
evaluated the circumtibial (CT), above-retinaculum transmembranous (TMAR), and under-retinaculum transmembranous
(TMUR) transfer gliding resistance and foot kinematics in a cadaveric foot model during ankle range of motion (ROM).
Methods: Eight cadaveric foot-ankle distal tibia specimens were dissected free of soft tissues on the proximal end,
applying an equivalent force to 50% of the stance phase to every tendon, except for the Achilles tendon. Dorsiflexion was
tested with all of the tibialis posterior tendon transfer methods (CT, TMAR, and TMUR) using a tension tensile machine. A
10-repetition cycle of dorsiflexion and plantarflexion was performed for each transfer. Foot motion and the force needed
to achieve dorsiflexion were recorded.
Results: The CT transfer showed the highest gliding resistance (P < .01). Regarding kinematics, all transfers decreased
ankle ROM, with the CT transfer being the condition with less dorsiflexion compared with the control group (6.8 vs 15
degrees, P < .05). TMUR transfer did perform better than TMAR with regard to ankle dorsiflexion, but no difference was
shown in gliding resistance. The CT produced a supination moment on the forefoot.
Conclusion: The CT transfer had the highest tendon gliding resistance, achieved less dorsiflexion and had a supination
moment.
Clinical Relevance We suggest that the transmembranous tibialis posterior tendon transfer should be the transfer of
choice. The potential bowstringing effect when performing a tibialis posterior tendon transfer subcutaneously (TMAR)
could be avoided if the transfer is routed under the retinaculum, without significant compromise of the final function and
even with a possible better ankle range of motion.
Keywords: tibialis posterior tendon transfer, circumtibial, transmembranous, interosseous membrane, paralytic foot,
dropfoot

Introduction
Tibialis posterior tendon transfer is used for different foot
and ankle pathologies that need rebalancing to achieve a
plantigrade foot. Injury to the common peroneal nerve is the
most frequent cause of dropfoot.9 Numerous other patho-
logies have dropfoot as one of their characteristics (eg,
Charcot Marie Tooth syndrome, trauma, spastic syndrome,
herniated disc, etc).1,4,7 In a posttraumatic setting, it is
important to differentiate whether dropfoot is secondary to
tendon or neurologic damage. In almost every dropfoot
case, loss of dorsiflexion has to be compensated. Initial con-
servative treatment for dropfoot varies greatly, but ankle
foot orthoses are often prescribed. The orthosis blocks plan-
tarflexion, which stabilizes the ankle, avoiding the equinus
gait. If conservative treatment fails, operative options
include arthrodesis, tenodesis, and tendon transfers.2

In addition to a failed conservative treatment, the follow-
ing are requirements to be a candidate for a tibialis posterior
tendon transfer in a dropfoot case: flexible ankle joint, nor-
mal ankle range of motion, absence of ankle joint arthritis,
M4 to M5 tibialis posterior tendon strength, and a viable
leg. If these requirements are not met, an ankle arthrodesis
should be considered.
1

Foot and Ankle Surgeon, Clinica Alemana-Universidad del Desarrollo,
Santiago, Chile
2
Hospital Militar de Santiago-Universidad de los Andes, Santiago, Chile
3
Laboratorio LIBFE, Escuela de Kinesiología, Facultad de Medicina,
Universidad de los Andes, Santiago, Chile
Corresponding Author:
Pablo Wagner, MD, Clinica Alemana-Universidad del Desarrollo,
Vitacura 5951, Santiago, 7550502, Chile.
Email: pwagner@alemana.cl

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