PubMed · 13113580
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B T BELL. 1953. Pelvic support osteotomy.. https://doi.org/10.1016/s0039-6109(16)34097-x
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OBJECTIVE: To design a reproducible method to measure femoral anteversion in children under 1 year old. DESIGN AND PATIENTS: We conducted a prospective, observational study to determine intra- and inter-observer reproducibility of the sonographic measurement of femoral anteversion in infants. The method involves imaging of the proximal femur using a vertical transducer with the infant in the lateral position. Anterior femoral anteversion is measured using a vertical baseline and a line tangential to the anterior femoral head and the trochanter (anterior anteversion). We similarly measured true femoral anteversion using a line passing through the centre of the femoral head and the femoral neck (true anteversion). Anteversion measurements were taken at the time of routine ultrasound screening for developmental dysplasia of the hip when infants were an average of 10.4 weeks old. Anteversion measurements were made in 74 hips (37 infants). RESULTS: Our results showed that for the anterior anteversion measurements intra-observer repeatability was +/-6.2 degrees and inter-observer repeatability was +/-7.8 degrees. For true anteversion measurements intra-observer repeatability was +/-9.5 degrees, but inter-observer repeatability was +/-23.5 degrees. CONCLUSIONS: Our results have shown that our method for measuring "anterior femoral anteversion" has an acceptable level of inter- and intra-observer agreement. The method used to determine "true anteversion", however, proved to have an unacceptable level of inter-observer variability.
Several virus inactivation procedures like heat treatment, gamma irradiation and chemical sterilization are used to increase the safety of bone tissue transplants. In this study we present data on the virus-inactivating effect of heat disinfection on human femoral heads, using the Marburg bone bank system 'Lobator sd-2'. Three enveloped viruses (human immunodeficiency virus type 2 [HIV-2], bovine viral diarrhoea virus as a model for Hepatitis C virus [HCV], and the herpesvirus pseudorabies virus), and three non-enveloped viruses (hepatitis A virus, poliomyelitis virus, and bovine parvovirus) were investigated. In a model system the central part of human femoral heads was contaminated with the respective cell-free virus suspension, establishing a direct contact between virus and native bone tissue. The core temperature in the femoral heads during the sterilization process was determined in additional model experiments. A temperature of 82.5 degrees C, given by the manufacturer as the effective temperature for virus inactivation, was maintained for at least 15 min in decartilaged femoral heads with a diameter of < or = 56 mm. Heat treatment using the Lobator sd-2 inactivated all viruses in human femoral heads below the detection limit (at least by a factor of > or =4 log(10)). By combining a well-focussed anamnesis of the donors and serological testing for relevant infection markers (anti-HIV-1/2, HBsAg, anti-HBcore, anti-HCV, TPHA) with heat treatment of femoral heads in the Lobator sd-2 system, a high safety level is achieved. To further increase virus safety of cadaveric bone transplants, it is recommended that multi-organ donors are tested by nucleic acid testing (i.e. polymerase chain reaction) for HIV, HBV and HCV genome.
Rotational stresses from box-post impingement have been implicated in the loosening of posterior-stabilized total knee prostheses. A bench model was constructed to assess the forces generated by tibiofemoral rotation. Rotational torque under load was measured in two different posteriorstabilized total knee prostheses using an axial-torsion load cell at 0 degrees, 20 degrees, and 40 degrees flexion over 20 degrees internal and external rotation. The Sigma posterior-stabilized prosthesis generated little torque through 5 degrees internal and external rotation. An increase in torque then occurred because of box-post impingement, generating peak torques of 17 to 18 N-m at 12 degrees to 14 degrees rotation. The bench model produced the same deformation of the polyethylene post as seen on retrieved specimens. The Scorpio posterior-stabilized prosthesis had a relatively continuous rise in generated torque from tibiofemoral conformity. Box-post impingement did not occur resulting in 32% lower torque between 12 degrees and 14 degrees rotation. Peak rotational torques of 15 to 16 N-m were reached at 19 degrees to 20 degrees rotation. Tibiofemoral conformity is the primary source of rotational constraint. Box-post impingement can be a source of additional rotational constraint. Depending on specific design features, small changes in relative tibiofemoral component rotation can more than double the generated torque. Axial rotation of the knee in vivo can generate substantial torque. Relative tibiofemoral rotational position is an important factor influencing component function and fixation.