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Taylor CE, Henninger HB, Bachus KN. Finite Element Analysis of Transhumeral and Transtibial Percutaneous Osseointegrated Endoprosthesis Implantation. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:744674. [PMID: 35178528 PMCID: PMC8849523 DOI: 10.3389/fresc.2021.744674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/21/2021] [Indexed: 06/14/2023]
Abstract
Cadaveric mechanical testing of a percutaneous osseointegration docking system (PODS) for osseointegration (OI) prosthetic limb attachment revealed that translation of the exact system from the humerus to the tibia may not be suitable. The PODS, designed specifically for the humerus achieved 1.4-4.8 times greater mechanical stability in the humerus than in the tibia despite morphology that indicated translational feasibility. To better understand this discrepancy, finite element analyses (FEAs) modeled the implantation of the PODS into the bones. Models from cadaveric humeri (n = 3) and tibia (n = 3) were constructed from CT scans, and virtual implantation preparation of an array of endoprosthesis sizes that made contact with the endosteal surface but did not penetrate the outer cortex was performed. Final impaction of the endoprosthesis was simulated using a displacement ramp function to press the endoprosthesis model into the bone. Impaction force and maximum first principal (circumferential) stress were recorded to estimate stability and assess fracture risk of the system. We hypothesized that the humerus and tibia would have different optimal PODS sizing criteria that maximized impaction force and minimized first principal stress. The optimal sizing for the humerus corresponded to implantation instructions, whereas for the tibia optimal sizing was three times larger than the guidelines indicated. This FEA examination of impaction force and stress distribution lead us to believe that the same endoprosthesis strategy for the humerus is not suitable for the tibia because of thin medial and lateral cortices that compromise implantation.
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Affiliation(s)
- Carolyn E. Taylor
- Department of Orthopaedics, School of Medicine, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, College of Engineering, University of Utah, Salt Lake City, UT, United States
| | - Heath B. Henninger
- Department of Orthopaedics, School of Medicine, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, College of Engineering, University of Utah, Salt Lake City, UT, United States
| | - Kent N. Bachus
- Department of Orthopaedics, School of Medicine, University of Utah, Salt Lake City, UT, United States
- Department of Biomedical Engineering, College of Engineering, University of Utah, Salt Lake City, UT, United States
- VA Salt Lake City Health Care System, Salt Lake City, UT, United States
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Hoellwarth JS, Tetsworth K, Akhtar MA, Al Muderis M. Transcutaneous osseointegration for amputees : lessons from the past of relevance to the future. Bone Joint Res 2021; 10:690-692. [PMID: 34666513 PMCID: PMC8559973 DOI: 10.1302/2046-3758.1010.bjr-2021-0235.r2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Jason Shih Hoellwarth
- Department of Orthopaedic Surgery, Macquarie University Hospital, Macquarie University, Macquarie Park, Australia.,Limb Lengthening and Complex Reconstruction, Hospital for Special Surgery, New York, New York, USA
| | - Kevin Tetsworth
- Department of Orthopaedic Surgery, Royal Brisbane and Women's Hospital, Herston, Australia
| | | | - Munjed Al Muderis
- Department of Orthopaedic Surgery, Macquarie University Hospital, Macquarie University, Macquarie Park, Australia
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Taylor CE, Henninger HB, Bachus KN. Virtual implantation technique to estimate endoprosthetic contact of percutaneous osseointegrated devices in the tibia. Med Eng Phys 2021; 93:1-7. [PMID: 34154769 DOI: 10.1016/j.medengphy.2021.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/13/2021] [Accepted: 05/18/2021] [Indexed: 11/25/2022]
Abstract
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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Affiliation(s)
- Carolyn E Taylor
- Department of Orthopaedics, University of Utah, 590 Wakara Way, Suite A100, Salt Lake City, Utah, United States; Department of Biomedical Engineering, University of Utah, 36 S Wasatch Drive SMBB 3100, Salt Lake City, Utah, United State
| | - Heath B Henninger
- Department of Orthopaedics, University of Utah, 590 Wakara Way, Suite A100, Salt Lake City, Utah, United States; Department of Biomedical Engineering, University of Utah, 36 S Wasatch Drive SMBB 3100, Salt Lake City, Utah, United State
| | - Kent N Bachus
- Department of Veterans Affairs, 500 Foothill Drive (151), Salt Lake City, UT, United States; Department of Orthopaedics, University of Utah, 590 Wakara Way, Suite A100, Salt Lake City, Utah, United States; Department of Biomedical Engineering, University of Utah, 36 S Wasatch Drive SMBB 3100, Salt Lake City, Utah, United State.
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Taylor CE, Drew AJ, Zhang Y, Qiu Y, Bachus KN, Foreman KB, Henninger HB. Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems. PLoS One 2020; 15:e0237179. [PMID: 32760149 PMCID: PMC7410272 DOI: 10.1371/journal.pone.0237179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 07/21/2020] [Indexed: 11/19/2022] Open
Abstract
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 limb-types: (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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Affiliation(s)
- Carolyn E. Taylor
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Alex J. Drew
- DJO Surgical, Austin, Texas, United States of America
| | - Yue Zhang
- Department of Epidemiology, University of Utah, Salt Lake City, Utah, United States of America
| | - Yuqing Qiu
- Department of Epidemiology, University of Utah, Salt Lake City, Utah, United States of America
| | - Kent N. Bachus
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
- Department of Veterans Affairs, University of Utah, Salt Lake City, Utah, United States of America
| | - K. Bo Foreman
- Department of Veterans Affairs, University of Utah, Salt Lake City, Utah, United States of America
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah, United States of America
| | - Heath B. Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Taylor CE, Henninger HB, Bachus KN. Cortical and medullary morphology of the tibia. Anat Rec (Hoboken) 2020; 304:507-517. [PMID: 32585072 DOI: 10.1002/ar.24479] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/28/2020] [Accepted: 05/07/2020] [Indexed: 12/17/2022]
Abstract
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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Affiliation(s)
- Carolyn E Taylor
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Heath B Henninger
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Kent N Bachus
- Department of Orthopaedics, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
- Department of Veterans Affairs, Salt Lake City, Utah, USA
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