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Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances.
Surg Technol Int 2019; 35ST

Abstract

BACKGROUND

Bone quality in hip fractures is poor and there is a need to not only correctly position metalwork within the femoral head, but also for implants to resist cut-out. New implant designs may help to reduce metalwork cut-out, leading to fewer failures of fixation. This study compared the cut-out strength of a Dynamic Hip Screw (DHS) to that of an X-Bolt® (X-Bolt Orthopaedics, Dublin, Ireland) implant in an osteoporotic Sawbones® (Sawbones, Vashon Island, WA) model.

METHODS

An unstable fracture model (AO 31-A2) was created using low-density 5 pound per cubic foot (pcf) Sawbones®. The DHS and X-Bolts® were inserted into the Sawbones® femoral head at Tip-Apex Distances (TAD) of 10mm, 15mm, 20mm, 25mm, 30mm and 40mm. A cyclic-loading Instron® machine (Instron Corp., Norwood, MA) pushed the bone at a compression rate of 5mm per minute at a 20-degree angle to the axis of the implant with an upper force limit of 4000N. Maximum force reached and load to failure, defined as movement of the implant by 5mm, were recorded. Four implants were used per group to give a total of 48 tests between the two groups.

RESULTS

The X-Bolt® demonstrated a superior average maximum total load push-out force compared to the DHS group for all of the TAD configurations tested. The maximum force reached in the X-Bolt® group was significantly higher than that in the DHS group at a TAD of 10mm (X-Bolt® 3299.25N vs. DHS 2843.75N, P<0.029) and 30mm (X-Bolt® 2908.25N vs. DHS 2030N, P<0.029). The X-Bolt® also had a higher load to failure than the DHS group at all of the TAD values tested.

CONCLUSIONS

The X-Bolt® implant gave superior performance compared to the standard DHS, as reflected by a greater push-out force in an osteoporotic Sawbones® model.

Authors+Show Affiliations

Gold Coast University Hospital, Queensland, Australia.Percivall Pott Rotation, Royal London Hospital, Barts Health NHS Trust, London, UK.Rothman Institute, Philadelphia, PA, USA.University College London, Institute of Orthopaedics & Musculoskeletal Science, Royal National Orthopaedic Hospital, Middlesex, UK.Royal Adelaide Hospital, University of Adelaide, South Australia, Australia.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31524281

Citation

Kahane, Steven, et al. "Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances." Surgical Technology International, vol. 35, 2019.
Kahane S, Vaghela KR, Stammers J, et al. Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances. Surg Technol Int. 2019;35.
Kahane, S., Vaghela, K. R., Stammers, J., Goldberg, A., & Smitham, P. (2019). Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances. Surgical Technology International, 35.
Kahane S, et al. Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances. Surg Technol Int. 2019 Sep 16;35 PubMed PMID: 31524281.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Biomechanical Study Comparing Cut-out Resistance of the X-Bolt® and Dynamic Hip Screw at Various Tip-Apex Distances. AU - Kahane,Steven, AU - Vaghela,Kalpesh R, AU - Stammers,John, AU - Goldberg,Andy, AU - Smitham,Peter, Y1 - 2019/09/16/ PY - 2019/9/17/entrez JF - Surgical technology international JO - Surg Technol Int VL - 35 N2 - BACKGROUND: Bone quality in hip fractures is poor and there is a need to not only correctly position metalwork within the femoral head, but also for implants to resist cut-out. New implant designs may help to reduce metalwork cut-out, leading to fewer failures of fixation. This study compared the cut-out strength of a Dynamic Hip Screw (DHS) to that of an X-Bolt® (X-Bolt Orthopaedics, Dublin, Ireland) implant in an osteoporotic Sawbones® (Sawbones, Vashon Island, WA) model. METHODS: An unstable fracture model (AO 31-A2) was created using low-density 5 pound per cubic foot (pcf) Sawbones®. The DHS and X-Bolts® were inserted into the Sawbones® femoral head at Tip-Apex Distances (TAD) of 10mm, 15mm, 20mm, 25mm, 30mm and 40mm. A cyclic-loading Instron® machine (Instron Corp., Norwood, MA) pushed the bone at a compression rate of 5mm per minute at a 20-degree angle to the axis of the implant with an upper force limit of 4000N. Maximum force reached and load to failure, defined as movement of the implant by 5mm, were recorded. Four implants were used per group to give a total of 48 tests between the two groups. RESULTS: The X-Bolt® demonstrated a superior average maximum total load push-out force compared to the DHS group for all of the TAD configurations tested. The maximum force reached in the X-Bolt® group was significantly higher than that in the DHS group at a TAD of 10mm (X-Bolt® 3299.25N vs. DHS 2843.75N, P<0.029) and 30mm (X-Bolt® 2908.25N vs. DHS 2030N, P<0.029). The X-Bolt® also had a higher load to failure than the DHS group at all of the TAD values tested. CONCLUSIONS: The X-Bolt® implant gave superior performance compared to the standard DHS, as reflected by a greater push-out force in an osteoporotic Sawbones® model. SN - 1090-3941 UR - https://www.unboundmedicine.com/medline/citation/31524281/Biomechanical_Study_Comparing_Cut-out_Resistance_of_the_X-Bolt®_and_Dynamic_Hip_Screw_at_Various_Tip-Apex_Distances DB - PRIME DP - Unbound Medicine ER -