Partial weight bearing of the tibia.
BACKGROUND
Partial weight bearing is part of treatment schemes in orthopedic surgery and traumatology. The aim of the present study was to explore to what degree ground reaction forces during partial weight bearing of the lower leg are related to given instructions and to tibia deformation.


METHODS
Tibia deformation (torsion, medio-lateral and anterio-posterior bending) was measured for rear foot and forefoot loading, 10kg, 20kg and half body weight instructions compared to full loading in five healthy male subjects using the "Optical Segment Tracking" approach, a motion-capturing based method that uses monocortically fixed bone screws.


RESULTS
1. Ground reaction force was a good indicator of tibia deformation. 2. Participants significantly under-loaded during half-body weight instructions (P<0.001) while they overloaded when loading the forefoot only. 3. Partial-loading instructions led to a highly significant and systematic reduction in peak ground reaction force (GRFpk) in all three types of tibia deformation with substantial variation between measurements. 4. Forefoot usage was associated with significant, albeit moderate increases in GRFpk (P=0.0031), in AP-bending (P=0.0027) and in torsion (P<0.001), compared to rear foot loading.


CONCLUSIONS
These findings result in the following clinical "lessons learned": 1. GRF is a good reflection of loading-induced deformation of the tibia. 2. GRFs are hard to control by subjects/patients. 3. The expectation that forefoot-loading results in larger tibia deformation could not be confirmed in our study. 4. When aiming at a reduction in tibia deformation, rear-foot loading is more preferable than forefoot loading.
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany; Department of Orthopedic Trauma Surgery, University Hospital RWTH Aachen, Aachen, Germany. Electronic address: bganse@ukaachen.de.
Bergita
B
Ganse
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany; Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an, China.
Peng-Fei
PF
Yang
Physiotherapy Center am Heumarkt, Cologne, Germany.
Jenny
J
Gardlo
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
Peter
P
Gauger
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
Andreas
A
Kriechbaumer
Department of Orthopedic Trauma Surgery, University Hospital RWTH Aachen, Aachen, Germany.
Hans-Christoph
HC
Pape
Department for Orthopedic Surgery and Traumatology, Cologne University Hospital, Cologne, Germany.
Timmo
T
Koy
Department for Orthopedic Surgery and Traumatology, Cologne University Hospital, Cologne, Germany.
Lars-Peter
LP
Müller
Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
Jörn
J
Rittweger
D000328:Adult; D001696:Biomechanical Phenomena; D005080:Exercise Test / Q000379:methods; D005545:Forefoot, Human / Q000502:physiology; D005684:Gait / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007869:Leg Injuries / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D011187:Posture / Q000502:physiology*; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D013977:Tibia / Q000502:physiology*; D054159:Torsion, Mechanical; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*
Fracture; Lower leg; Motion capturing; Orthopaedic surgery; Partial weight bearing; Physiotherapy; Tibia; Traumatology; Unloading