Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Navigation
Abstract number: 23434
HIP RESURFACING: THE RISK FEMORAL NECK FRACTURE AFTER ANTERIOR
OR POSTERIOR FEMORAL NECK NOTCHING.
Gordon HIGGINS, Zac MORISON, Peter LEWIS, Michael OLSEN, Emil
SCHEMITSCH
St. Michaels Hospital, University of Toronto, Torbay (UNITED KINGDOM)
Method: 47 fourth generation synthetic femora were implanted with Hip Resurfacing
prostheses using imageless computer navigation. The prosthesis was initially
planned for neutral version and translated anterior, or posterior, to create a femoral
neck notch. The femora were fixed in a single-leg stance, 25° flexion/extension, and
tested with axial compression using a mechanical testing machine. The results were
compared to the control group in neutral alignment using a one- way ANOVA.
Results: Testing Group Mean load to failure. Significance (p-value) Anterior
2mm3926.61 ± 894.17 .843 Anterior 5mm 3374.64 ± 345.65. 155Neutral (Control)
4539.44 ± 786.44 - Posterior 2mm 4208.09 ± 1079.81. 994 Posterior 5mm
3988.06 ± 728.59 .902Superior 5mm 2423.07±424.17. 001 Anterior 5mm in 25°
flexion 3048.11 ± 509.24 027 Posterior 5mm in 25° extension 3104.62 ± 592.67.
038Anterior and posterior two mm or five mm notches are not significantly weaker in
axial compression. Anterior and posterior 5mm notches are significantly weaker in
flexion/extension (p=0.027/ p=0.038). The five mm superior notch group was
significantly weaker with axial compression supporting previous published data
(p=0.001). Conclusion: Anterior or posterior two mm notching of the femoral neck has
no clinical implications, however five mm anterior or posterior femoral neck notching
significantly weakens the femoral neck. Hip resurfacing is commonly performed on
active patients and five mm neck notching has clinically important implications.
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