Loading compliance of static load bearing exercises performed by transfemoral amputees fitted with an osseointegrated implant

Vertriest, Sofie, Coorevits, Pascal, Hagberg, Kerstin, Branemark, Rickard, Haggstrom, Eva, Vanderstraeten, Guy, & Frossard, Laurent (2015) Loading compliance of static load bearing exercises performed by transfemoral amputees fitted with an osseointegrated implant. In XV World Congress of the International Society for Prosthetics and Orthotics (ISPO), 22-25 June 2015, Lyon, France.

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To date bone-anchored prostheses are used to alleviate the concerns caused by socket suspended prostheses and to improve the quality of life of transfemoral amputees (TFA). Currently, two implants are commercially available (i.e., OPRA (Integrum AB, Sweden), ILP (Orthodynamics GmbH, Germany)). [1-17]The success of the OPRA technique is codetermined by the rehabilitation program. TFA fitted with an osseointegrated implant perform progressive mechanical loading (i.e. static load bearing exercises (LBE)) to facilitate bone remodelling around the implant.[18, 19]


This study investigated the trustworthiness of monitoring the load prescribed (LP) during experimental static LBEs using the vertical force provided by a mechanical bathroom scale that is considered a surrogate of the actual load applied.


Eleven unilateral TFAs fitted with an OPRA implant performed five trials in four loading conditions. The forces and moments on the three axes of the implant were measured directly with an instrumented pylon including a six-channel transducer. The “axial” and “vectorial” comparisons corresponding to the difference between the force applied on the long axis of the fixation and LP as well as the resultant of the three components of the load applied and LP, respectively were analysed


For each loading condition, Wilcoxon One-Sample Signed Rank Tests were used to investigate if significant differences (p<0.05) could be demonstrated between the force applied on the long axis and LP, and between the resultant of the force and LP. The results demonstrated that the raw axial and vectorial differences were significantly different from zero in all conditions (p<0.05), except for the vectorial difference for the 40 kg loading condition (p=0.182). The raw axial difference was negative for all the participants in every loading condition, except for TFA03 in the 10 kg condition (11.17 N).

Discussion & Conclusion

This study showed a significant lack of axial compliance. The load applied on the long axis was significantly smaller than LP in every loading condition. This led to a systematic underloading of the long axis of the implant during the proposed experimental LBE. Monitoring the vertical force might be only partially reflective of the actual load applied, particularly on the long axis of the implant.

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ID Code: 89033
Item Type: Conference Paper
Refereed: Yes
Additional URLs:
Keywords: Osseointegration, Bone-anchored prosthesis, Implant, Amputation, Rehabiliation
DOI: 10.1177/0309364615591101
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > BIOMEDICAL ENGINEERING (090300) > Rehabilitation Engineering (090305)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Exercise & Nutrition Sciences
Copyright Owner: Copyright 2015 [please consult the authors]
Deposited On: 13 Oct 2015 23:38
Last Modified: 15 Oct 2015 23:08

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