Limits...
An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA.

Zhu Z, Ding H, Shao H, Zhou Y, Wang G - J Orthop Surg Res (2013)

Bottom Line: Ten cadaveric femurs were chosen in this study.The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively.The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.

ABSTRACT

Background: The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.

Methods: An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

Results: In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.

Conclusions: The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.

Show MeSH

Related in: MedlinePlus

In the vertical tension test (a), eight markers were used: the femoral bed (A, B, C), the extended greater trochanter (D, E, F), the actuator (G, H). In the lateral tension test (b), the specimen was placed horizontal.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3643827&req=5

Figure 3: In the vertical tension test (a), eight markers were used: the femoral bed (A, B, C), the extended greater trochanter (D, E, F), the actuator (G, H). In the lateral tension test (b), the specimen was placed horizontal.

Mentions: 3) Measurement Devices: The three dimensional (3D) motion between the femoral bed and the fragment was tracked by an Optotrak Certus™ optoelectronic camera system (Northern Digital, Waterloo, Canada). A servo hydraulic material testing system (MTS858, with 25kN ± 5N axial force load cell, 250 Nm torque capacity, Eden Prairie, MN USA) was used to supply a tension from 0 N to 500 N with an increment of 1N per second. The sampling rate for motion data was set to 10 Hz. A self-developed minitype infrared active marker connected to the NDI system was used (Figure 2), which was validated as well as the NDI standard markers with a root-mean-square (RMS) accuracy of 0.1 mm. There were two roots on each maker to mount to the bone. Each root was less than 1 mm in diameter and 4–5 mm in length. Eight markers were used to track the motion of the femoral bed (A, B, C), the cut bone (D, E, F) and the MTS actuator (G, H) (Figure 3 (a)). The Marker D was 10 mm from the horizontal cut. The cluster of three markers on the same side was placed non-linear. The markers were placed in similar position on different specimens. Two makers that attached to the MTS actuator were used to synchronize the MTS and the motion tracking system.


An in-vitro biomechanical study of different fixation techniques for the extended trochanteric osteotomy in revision THA.

Zhu Z, Ding H, Shao H, Zhou Y, Wang G - J Orthop Surg Res (2013)

In the vertical tension test (a), eight markers were used: the femoral bed (A, B, C), the extended greater trochanter (D, E, F), the actuator (G, H). In the lateral tension test (b), the specimen was placed horizontal.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643827&req=5

Figure 3: In the vertical tension test (a), eight markers were used: the femoral bed (A, B, C), the extended greater trochanter (D, E, F), the actuator (G, H). In the lateral tension test (b), the specimen was placed horizontal.
Mentions: 3) Measurement Devices: The three dimensional (3D) motion between the femoral bed and the fragment was tracked by an Optotrak Certus™ optoelectronic camera system (Northern Digital, Waterloo, Canada). A servo hydraulic material testing system (MTS858, with 25kN ± 5N axial force load cell, 250 Nm torque capacity, Eden Prairie, MN USA) was used to supply a tension from 0 N to 500 N with an increment of 1N per second. The sampling rate for motion data was set to 10 Hz. A self-developed minitype infrared active marker connected to the NDI system was used (Figure 2), which was validated as well as the NDI standard markers with a root-mean-square (RMS) accuracy of 0.1 mm. There were two roots on each maker to mount to the bone. Each root was less than 1 mm in diameter and 4–5 mm in length. Eight markers were used to track the motion of the femoral bed (A, B, C), the cut bone (D, E, F) and the MTS actuator (G, H) (Figure 3 (a)). The Marker D was 10 mm from the horizontal cut. The cluster of three markers on the same side was placed non-linear. The markers were placed in similar position on different specimens. Two makers that attached to the MTS actuator were used to synchronize the MTS and the motion tracking system.

Bottom Line: Ten cadaveric femurs were chosen in this study.The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively.The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.

ABSTRACT

Background: The wire fixation and the cable grip fixation have been developed for the extended trochanteric osteotomy (ETO) in the revision of total hip arthroplasty (THA). Many studies reported the postoperative performance of the patients, but with little quantitative biomechanical comparison of the two fixation systems.

Methods: An in-vitro testing approach was designed to record the loosening between the femoral bed and the greater trochanter after fixations. Ten cadaveric femurs were chosen in this study. Each femur underwent the THA, revision by ETO and fixations. The tension to the greater trochanter was from 0 to 500N in vertical and lateral direction, respectively. The translation and rotation of the greater trochanter with respect to the bony bed were captured by an optical tracking system.

Results: In the vertical tension tests, the overall translation of the greater trochanter was observed 0.4 mm in the cable fixations and 7.0 mm in the wire fixations. In the lateral tension tests, the overall motion of the greater trochanter was 2.0 mm and 1.2° in the cable fixations, while it was 6.2 mm and 5.3° in the wire fixations. The result was significantly different between the two fixation systems.

Conclusions: The stability of the proximal femur after ETO using different fixations in the revision THA was investigated. The cable grip fixation was significantly more stable than the wire fixation.

Show MeSH
Related in: MedlinePlus