Genetic parameters for intramuscular fat percentage, marbling score, scrotal circumference, and heifer pregnancy in Red Angus cattle.

Selection criteria for yearling bulls commonly include indicators of fertility and carcass merit, such as scrotal circumference (SC) and intramuscular fat percentage (IMF). Genetic correlation estimates between ultrasound traits such as IMF and carcass marbling score (MS) with fertility traits SC and heifer pregnancy (HP) have not been reported. Therefore, the objective of this study was to estimate the genetic parameters among the indicator traits IMF and SC, and the economically relevant traits MS and HP. Records for IMF (n=73,051), MS (n=15,260), SC (n=43,487), and HP (n=37,802) were obtained from the Red Angus Association of America, and a 4-generation ancestral pedigree (n=10,460) was constructed from the 8,915 sires represented in the data. (Co)variance components were estimated using a multivariate sire model and average information REML to obtain estimates of heritability and genetic correlations. Fixed effects included contemporary group and the linear effect of age at measurement for all traits, and an additional effect of age of dam for both HP and SC. The random effect of sire was included to estimate additive genetic effects, which were assumed to be continuous for IMF, MS, and SC, but a probit threshold link function was fitted for HP. Generally moderate heritability estimates of 0.29 ± 0.01, 0.35 ± 0.06, 0.32 ± 0.02, and 0.17 ± 0.01 were obtained for IMF, MS, SC, and HP on the underlying scale, respectively. The confidence interval for the estimated genetic correlation between MS and HP (0.10 ± 0.15) included zero, suggesting a negligible genetic association. The genetic correlation between MS and IMF was high (0.80 ± 0.05), but the estimate for HP and SC (0.05 ± 0.09) was near zero, as were the estimated genetic correlations of SC with MS (0.01 ± 0.08) and IMF (0.05 ± 0.06), and for HP with IMF (0.13 ± 0.09). These results suggest that concomitant selection for increased fertility and carcass merit would not be antagonistic.

Allograft reconstruction of the acetabulum in revision hip surgery.

Acetabular deficiencies seen in revision hip arthroplasty require special attention. Custom components, space-filling cement, relocation of the hip center higher on ilium, and resection arthroplasties have all been used. Allograft reconstruction of acetabular defects has many attractive features, but methods of fixation, long-term success rates, and problems of graft resorption and implant loosening present significant questions. This article presents a classification system for acetabular defects and a surgical technique for correcting them. The results of 218 cementless acetabular reconstructions are reviewed and show the importance of the acetabular rim. When the rim is intact, 97% of reconstructions will remain stable, and 78% of allografts used will consolidate. When the acetabular rim is deficient, special techniques using bulk allograft and internal fixation must be used in order to avoid long-term graft resorption and implant loosening.

Polyethylene debris-induced osteolysis and loosening in uncemented total hip arthroplasty. A cause of late failure.

Uncemented total hip arthroplasty has proven to be an acceptable alternative to cemented total hip arthroplasty with good short-term results. With the elimination of the use of polymethyl methacrylate for component fixation, failure at the bone-cement interface, with resultant osteolysis and progressive loosening, was thought to be preventable. Unfortunately the ultra-high-molecular-weight polyethylene acetabular insert can wear and produce particulate debris. This debris can stimulate an osteolytic reaction and lead to late aseptic loosening in a cementless total hip arthroplasty.

Clostridium perfringens and Staphylococcus epidermidis polymicrobial septic arthritis. A case report.

Septic arthritis caused by Clostridium perfringens is extremely rare. Previously there has been only one report of Clostridium perfringens in combination with an aerobe causing septic arthritis. This report presents a 23-year-old man with a mixed aerobic/anaerobic septic arthritis treated with intravenous antibiotics and repeated surgical drainage. It is the only report to date of a polymicrobial septic arthritis involving both Staphylococcus epidermidis and Clostridium perfringens. This report and a review of the literature demonstrate the existence of polymicrobial septic arthritis and illustrate its fulminant nature.