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T. Fujita1, K. Okazawa1, Y. Nasu1, M. Miyazato1, K. Kawaguchi2, M. Fujii2, S. Hamai2, Y. Nakashima2
1Kyushu University Hospital, Department of Rehabilitation, Fukuoka, Japan, 2Kyushu University Graduate School of Medical Sciences, Department of Orthopedic Surgery, Fukuoka, Japan
Background: Artificial talus replacement is a procedure in which only the talus bone is replaced with an artificial talus for osteoarthritis and talar necrosis. Although there have been scattered clinical reports of this procedure in recent years, there have been no reports of gait biomechanics. As a result, the endpoints currently reported are limited and are an obstacle to physical therapy.
Purpose: The purpose of this study is to explore the changes in ankle kinematics during gait from preoperative to one year postoperatively for artificial talus replacement.
Methods: The subjects were a female patient (age 72 years, BMI 28.3 kg/m2) who underwent artificial talus replacement for unilateral talus necrosis. A three-dimensional motion analysis device (VICON Vero v2.2) and floor reaction force meter were used to analyze the patient's comfortable walking barefoot before and one year after surgery. The Plug-in-gait lower body model and the Oxford Foot Model were used to analyze the surgical side. The ankle plantar dorsiflexion angle, ST joint inversion eversion angle, and the vertical of ground reaction force (vGRF) were examined. Each data was set at 100% of one gait cycle and was an additive average of three trials.
Results: The data for each are presented in the order of preoperative and 1 year postoperatively. Peak ankle joint angles were 3.2±0.1° and 26.4±4.1° for dorsal flexion and 6.2±0.7° and 2.4±1.4° for plantar flexion. Peak ST joint angles were 5.3±0.5° and -0.9±1.3° for eversion angle and 2.7±0.1° and 4.8±0.2° for inversion angles. The percentages of vGRF action during the gait cycle were 69 ± 0.8% and 66 ± 0.6%.
Conclusion(s): One year after surgery, the dorsal flexion angle of the ankle joint was greatly improved over the preoperative period, but the plantarflexion angle was lower than preoperatively. And the ST joint eversion angle after initial ground contact did not show any motion to the eversion position at 1 year postoperatively. Also, the vGRF action rate was slightly shorter one year after surgery than before, but the stance phase was still prolonged. In general, the ST joint performs eversion movement after initial contact and has the function of shock absorption and load transfer to the forefoot. Compared to reports of healthy patients from previous studies, it can be said that there is a prolonged prolongation of ankle plantar flexion and ST joint eversion limitation even one year after surgery. The limitation of the hindfoot kinematics may be responsible for the prolonged stance period.
Implications: Exercises to improve foot flexibility, including the ST joint as well as the ankle joint, are important. Besides, this study may have some clinical significance as there have been no previous reports with sufficient statistical description.
Funding, acknowledgements: The authors declare that there is no conflict of interest.
Keywords: artificial talus replacement, gait, kinematics
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Kyushu University
Committee: Medical District Department Ethics Review Committee
Ethics number: 36-22
All authors, affiliations and abstracts have been published as submitted.
