Initial stability of a percutaneous osseointegrated endoprosthesis with proximal interlocking screws for transhumeral amputees

Drew, Alex J.; Taylor, Craig; Tashjian, Robert Z.; Chalmers, Peter N.; Henninger, Heath B.; Bachus, Kent N.

doi:10.1016/j.clinbiomech.2019.12.005

Cited by 7 publications

(26 citation statements)

References 28 publications

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“…Amputation level was a major factor in bending and axial loading directions, with the largest impact on bending. Finally, these data supported the use of bicortical screws to improve torsional stability when compared to ultimate failure of a transhumeral percutaneous OI endoprosthesis [22], since this was only scenario where all analyzed activities could be completed with any prosthesis at any amputation level compared to laboratory test data. These findings stress the importance of 1) utilizing accurate prosthesis weight distribution in motion capture and load estimates for amputees, 2) considering desired prosthesis and residual limb length when prescribing rehabilitation, and 3) the risk of mechanical compromise when completing AADLs with prostheses during the early post-operative period.…”

Section: Plos Onementioning

confidence: 59%

“…In comparisons between the present data and the mean yield and ultimate failure of a transhumeral OI implant [22], there were no cases where modeled axial pullout exceeded yield (784. . Under torsional loading, the advanced prosthesis during internal roation and jumping jack, and myoelectric hand during internal rotation, exceeded yield at the proximal and distal level (4.5-10.2 Nm).…”

Section: Aadl Loading Versus Implant Failurementioning

confidence: 64%

“…The only condition that was not at risk for any prosthetic models, activities, and loading modalities was ultimate failure at the proximal and distal levels when compared to implants with the use of stabilzing screws. It is important to note that all these loading values reported for the bone-implant interface are far below the minimum expected implant failure threshold for the implant tested in Drew et al [22] (~28 kN shear load to fracture for the smallest implant size, data not shown, esimtated from FE models of the implant design).…”

Section: Aadl Loading Versus Implant Failurementioning

confidence: 77%

“…The purpose of this study was to examine the impact of prosthesis type on the estimated forces at the bone-implant interface of a transhumeral percutaneous OI endoprosthesis. We analyzed the contributions of prosthesis type and residual limb length, and compared each case to failure testing data from a transhumeral percutaneous OI system [22] to determine which loading…”

Section: Discussionmentioning

confidence: 99%

“…Finally, a one-sided one-sample Wilcoxon Signed-Rank Test was performed to compare the median of observed loading values to the physical implant loading values from Drew and Taylor et al [22]. That study examined yield and ultimate failure of the interface between the bone and a porous coated transhumeral OI endoprosthesis at time-zero before bone ingrowth (not the implant failure itself), both with and without the use of stabilizing screws in axial, torsion, and bending loading modalities for proximal (30%) and distal (65%) amputation levels.…”

Section: Plos Onementioning

confidence: 99%

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Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems

et al. 2020

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Percutaneous osseointegrated (OI) implants are increasingly viable as an alternative to socket suspension of prosthetic limbs. Upper extremity prostheses have also become more complex to better replicate hand and arm function and attempt to recreate pre-amputation functional levels. With more functionality comes heavier devices that put more stress on the bone-implant interface, which could be an issue for implant stability. This study quantified transhumeral loading at defined amputation levels using four simulated prosthetic limbtypes: (1) body powered hook, (2) myoelectric hook, (3) myoelectric hand, and (4) advanced prosthetic limb. Computational models were constructed to replicate the weight distribution of each prosthesis type, then applied to motion capture data collected during Advanced Activities of Daily Living (AADLs). For activities that did not include a handheld weight, the body powered prosthesis bending moments were 13-33% (range of means for each activity across amputation levels) of the intact arm moments (reference 100%), torsional moments were 12-15%, and axial pullout forces were 30-40% of the intact case (p�0.001). The myoelectric hook and hand bending moments were 60-99%, torsional moments were 44-97%, and axial pullout forces were 62-101% of the intact case. The advanced prosthesis bending moments were 177-201%, torsional moments were 164-326%, and axial pullout forces were 133-185% of the intact case (p�0.001). The addition of a handheld weight for briefcase carry and jug lift activities reduced the overall impact of the prosthetic model itself, where the body powered forces and moments were much closer to those of the intact model, and more complex prostheses further increased forces and moments beyond the intact arm levels. These results reveal a ranked order in loading magnitude according to complexity of the prosthetic device, and highlight the importance of considering the patient's desired terminal device when planning post-operative percutaneous OI rehabilitation and training.

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Section: Plos Onementioning

confidence: 59%

Section: Aadl Loading Versus Implant Failurementioning

confidence: 64%

Section: Aadl Loading Versus Implant Failurementioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Plos Onementioning

confidence: 99%

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Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems

et al. 2020

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Cortical and medullary morphology of the tibia

Taylor

Henninger

Bachus

2020

The Anatomical Record

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Bone resorption caused by stress shielding and insufficient bone‐implant contact continues to be problematic for orthopedic endoprostheses that utilize osseointegration (OI) for skeletal fixation. Morphologic analyses have helped combat this issue by defining anatomic parameters to optimize endoprosthesis loading by maximizing bone‐implant contact. These studies have not typically included diaphyseal medullary morphology, as this region is not pertinent to total joint replacement. To the contrary, percutaneous OI endoprostheses for prosthetic limb attachment are placed in the diaphysis of the long bone. This study examined the cortical and medullary morphology of 116 fresh‐frozen human cadaveric tibia using computed tomography. Anatomic landmarks were selected and custom MATLAB scripts were used to analyze the cross‐sectional cortical and medullary morphology normalized to biomechanical length (BML). BML measured the distance between the tibial plateau and the tibial plafond. Properties such as cortical thickness, medullary diameter, and circularity of the medullary canal were quantified. We tested the influence of sex and laterality on morphology, and examined variations along the length of the bone. Results showed that while both sex and laterality impacted the location of anatomic landmarks, only sex influenced cross‐sectional morphology. Overall, morphology significantly affected shape along the length of the bone for all examined properties except medullary circularity. This analysis found that distal to 35% BML, the canal is conducive to a circular implant, with medullary diameter ranging from 13 to 32 mm between 20 and 80% BML. A large size range is necessary for sufficient implant contact in order to accommodate residual limb length after amputation.

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Virtual implantation technique to estimate endoprosthetic contact of percutaneous osseointegrated devices in the tibia

Taylor

Henninger

Bachus

2021

Medical Engineering & Physics

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Percutaneous osseointegrated (OI) devices have an endoprosthesis attached to the residual bone of an amputated limb, then pass permanently through the skin to be connected to the distal prosthetic componentry outside of the body. Whether the bone-anchoring region of current OI endoprostheses are cylindrical, and/or conical, they require intimate bone-endoprosthesis contact to promote stabilizing bone attachment. However, removing too much cortical bone to achieve more contact leads to thinner and, subsequently, weaker cortical walls. Endoprostheses need to be designed to balance these factors, namely maximizing the contact, while minimizing the volume of bone removed. In this study, 27 human tibias were used to develop and validate a virtual implantation method. Then, 40 additional tibias were virtually implanted with mock cylindrical and conical bone-anchoring regions at seven residual limb lengths to measure resultant bone-endoprosthesis contact and bone removal. The ratio of bone-endoprosthesis contact to bone volume removed showed the conical geometry had more contact area per volume bone removed for all amputation levels (p≤0.001). In both mock devices, cortical penetration of the endoprosthesis at 20% residual length occurred in 74% of cases evaluated, indicating that alternative endoprosthesis geometries may be needed for clinical success in that region of bone.

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Initial stability of a percutaneous osseointegrated endoprosthesis with proximal interlocking screws for transhumeral amputees

Cited by 7 publications

References 28 publications

Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems

Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems

Cortical and medullary morphology of the tibia

Virtual implantation technique to estimate endoprosthetic contact of percutaneous osseointegrated devices in the tibia

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