Reduction of Broach Rotation for Versys Fibermetal Tapered Stem during the Femoral Canal Shaping / 대한정형외과연구학회지

PURPOSE: Inaccurate femoral canal shaping can result in post-operative complications in hip arthroplasty. We addressed the amount of broach rotation during shaping of the femoral canal and compared it with respect to newly designed broaches which were modified to minimize the rotation. MATERIALS AND METHOD: we designed the broaches that had canal guide which restricts the broach motion such that it is always aligned with the femoral axis while the broach machines the metaphyseal bone. Conventional broaches and the modified broach applied to 5 pair of fresh-frozen cadaver femurs and its spatial motion was measured with motion tracker. Rotations in coronal, saggital and frontal plane during the final 10 mm of broach advance were measured. RESULTS: 2.4..of axial rotation was occurred during final 10 mm advance of broach in the conventional method, which was the largest component of the rotation. Rotation of the broach during machining was decreased to 37% (p=0.075) and 25% (p=0.042) in the sagittal plane and coronal plane, respectively, by proposed method. CONCLUSION: The canal guide in the proposed method significantly reduced the rotation of the broach without any extra incision or measurement devices, resulting in increased accuracy in the femoral canal shaping.

In Vitro Measurement of the Interface Micromotion at the Cemented Total Hip Arthroplasty System with Different Surface Roughness / 대한정형외과연구학회지

PURPOSE: The relative movements of the stem-cement interface and the cement-bone interface were measured in the cadaver femur with stems of different surface roughness. MATERIALS AND METHODS: A stem which have polished surface and a stem which have roughen surface were used in the experiments, and their materials and shapes were virtually same. We inserted 5 stems of each type to the cadaver femur, that is overall 10 femur, and applied cyclic load to the femoral head of the stem to mimic the walking loads. The cyclic relative motions of stem-cement interface and cement-bone interface were measured by custom-made sensors. RESULT: Stem-cement interface motion was 13 micrometer for the stem with polished surface and 4.5 micrometer for the stem with rough stem. It showed interface motion of 5 micrometer for the bone-cement interface for overall cases. CONCLUSION: The relative interface motion of the stem-cement interface is affected by the surface roughness of the stem. But for the bone-cement interface, it cannot be said that the surface roughness of the stem affects the interface motion.

Association of Lipoprotein Lipase Gene Polymorphism and Coronary Artery Disease in Korean

BACKGROUND: The accumulation of lipoprotein and monocyte in the intima of the arterial wall is the most important step of the development of coronary artery disease (CAD). Lipoprotein lipase (LPL) plays an anti-atherogenic role by lipolysis of triglyceride-rich lipoproteins, but, it may also act as a receptor of some lipoproteins and monocyte at the arterial wall and act as a atherogenic molecule. Previous studies showed somewhat contradictory results about the association of CAD and LPL polymorphisms and mutations. Racial and dietary difference may contribute to these contradictory results. In this study, we tried to find out the association of CAD and the genetic variation of the LPL (PvuII RFLP in intron 6, HindIII RFLP in intron 8 and Ser 447 Ter mutation in exon 9) in Korean population. METHOD AND RESULT: CAD patients (n=146), confirmed by coronary angiography and healthy Korean adult volunteers (n=110) were genotyped for PvuII/HindIII RFLP and Ser447Ter mutation of the LPL gene by PCR-digestion method. Between two groups, the genotype frequency of these genetic variations was not different. But, the genetic variations showed different effect on lipid profile and body mass index (BMI) in the CAD group and in the control group. In the CAD group, P1 allele carriers showed higher total cholesterol (P1P1+P1P2:P2P2=216+-51 mg/dl:198+/-38 mg/dl, p=0.039) and higher LDL cholesterol level (P1P1+P1P2:P2P2=143+/-46 mg/dl:126+/-36 mg/dl, p=0.047), and H1 allele carriers had lower Body mass index than non-carriers (23.8+/-2.3 kg/m2 :24.8+/-2.9 kg/m2 , p=0.047). In the control group, the Ser447Ter mutation carriers had higher HDL cholesterol level than non-carriers (59+/-10mg/dl versus 53+/-11mg/dl, p=0.049) and patients with P1 allele showed lower body mass index (P1P1+P1P2: P2P2=23.1+/-2.6 kg/m 2 :24.5+/-2.6 kg/m2 , p=0.006). CONCLUSION: In Korean, PvuII/HindIII RFLP and Ser447Ter mutation was not associated with CAD, and they showed different effect on the lipid profile and on the body mass index according to the study group. These results suggests that the phenotypic characteristics of the LPL gene of the Korean people are different from those of occidental people.