Case report: Rhodococcus erythropolis osteomyelitis in the toe.

The Rhodococcus species rarely cause musculoskeletal infections, with only two cases reported in the literature. We report the case of a 53-year-old woman who had an infection develop after first metatarsophalangeal joint fusion. A year after surgery, she continued to have pain and swelling with nonunion. She underwent revision of the arthrodesis and tissue samples from surgery revealed Rhodococcus erythropolis. The patient's symptoms improved with oral antibiotics. One year after the revision surgery, the fusion had united. We believe this is the first report of a case of a musculoskeletal infection caused by Rhodococcus erythropolis.

Retrospective review of patients with atypical bisphosphonate related proximal femoral fractures.

INTRODUCTION: Patients may be at an increased risk of atypical proximal femoral fractures with prolonged bisphosphonate use. PATIENTS AND METHODS: This was a retrospective review of patients who sustained a subtrochanteric fracture of the femur in our department between April 2009 and March 2014. The radiographs were reviewed for features of atypical femoral fractures as described by the American Society of Bone Mineral Research. RESULTS: 185 patients were coded according to the National Hip Fracture Database as having sustained a subtrochanteric fracture of the femur. Of these, 26 patients had radiographic findings consistent with an atypical subtrochanteric fracture. 5 patients were excluded as their histology confirmed malignancy. 12 patients were taking bisphosphonates on admission. All 12 patients were females taking alendronic acid on admission, who sustained the fracture as the result of minimal or no trauma and underwent long gamma nail fixation. The mean age was 71.6 years (range 62-79 years). The mean length of time on bisphosphonates prior to admission was 8.33 years (range 3-25 years). 9/12 patients had pre-existing symptoms for between 5days and 2 years prior to admission. 1 patient sustained a broken gamma nail 14 weeks post-operatively requiring revision. The mean time to discharge from theatre was 16days (range 5-57days). The mean time to radiological union in the patients in whom there was evidence was 24 weeks. CONCLUSIONS: In this small group of patients, management of this fracture pattern can be complex with the potential for delayed or non-union and prodromal symptoms are common.

Are Albumin Levels a Good Predictor of Mortality in Elderly Patients with Neck of Femur Fractures?

BACKGROUND: Neck of femur (NOF) fractures are associated with significant morbidity and mortality in elderly people with multiple co-morbidities; making management of this patient subgroup challenging. Predictors of an increase in morbidity and mortality would therefore provide a useful framework for the assessment and management of this demographic. Within the current literature, hypoalbuminaemia (<35g/dl) has been highlighted as being a good biochemical predictor of short-term mortality (<12 months). Our aims were to assess whether there was an association between low albumin levels and mortality and whether the severity adversely affects outcomes. MATERIALS AND METHODS: Patients admitted to our large district hospital between January 2011 and December 2012 who had sustained a NOF fracture, were over 65 years old and had a pre-operative albumin level were included. This retrospective, longitudinal, observational study concluded in July 2014. Demographic and pre-operative function and albumin data was collated retrospectively. An association with mortality was made. RESULTS: 471 patients had usable data. Mean pre-operative albumin level was 29.5g/dl (SD 6.22g/dl) in patients who died and 32.8g/dl (SD 6.43g/dl) in patients who survived during the study period. Pre-operative albumin level was significantly associated with survival (hazard ratio 0.957: 95% CI (0.937, 0.978); p<0.001). Thus, a reduction of 1g/dl in pre-operative albumin is associated with an increased hazard of death of 4.3%. CONCLUSIONS: Early identification of patients with hypoalbuminaemia on admission with a venous blood sample and timely input from orthogeriatrians could optimise these patients pre- and post-operatively. This may enable rates of morbidity and mortality to fall. Hypoalbuminaemia may be a reasonable predictor of shorter-term mortality in this patient subgroup. However, this may reflect existing co-morbidities rather than an isolated cause. This study supports an association between hypoalbuminaemia and poorer outcome for patients with NOF fractures.

Restriction enzymes increase efficiencies of illegitimate DNA integration but decrease homologous integration in mammalian cells.

Mammalian cells repair DNA double-strand breaks by illegitimate end-joining or by homologous recombination. We investigated the effects of restriction enzymes on illegitimate and homologous DNA integration in mammalian cells. A plasmid containing the neo(R) expression cassette, which confers G418 resistance, was used to select for illegitimate integration events in CHO wild-type and xrcc5 mutant cells. Co-transfection with the restriction enzymes BamHI, BglII, EcoRI and KpnI increased the efficiency of linearized plasmid integration up to 5-fold in CHO cells. In contrast, the restriction enzymes did not increase the integration efficiency in xrcc5 mutant cells. Effects of restriction enzymes on illegitimate and homologous integration were also studied in mouse embryonic stem (ES) cells using a plasmid containing the neo(R) gene flanked by exon 3 of HPRT: The enzymes BamHI, BglII and EcoRI increased the illegitimate integration efficiency of transforming DNA several-fold, similar to the results for CHO cells. However, all three enzymes decreased the absolute frequency of homologous integration approximately 2-fold, and the percentage of homologous integration decreased >10-fold. This suggests that random DNA breaks attract illegitimate recombination (IR) events that compete with homology search.

Polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin induce intrachromosomal recombination in vitro and in vivo.

Polychlorinated aromatic hydrocarbons such as polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are extremely stable and widely distributed environmental pollutants. These chemicals are animal carcinogens and probable human carcinogens, and TCDD is possibly one of the most potent toxins ever evaluated by the United States Environmental Protection Agency. Polychlorinated aromatic hydrocarbons score negatively in most genotoxicity assays, including the Ames (Salmonella) assay. Although their mechanism of toxicity is not well understood, they induce aryl hydrocarbon (AH) hydroxylases and bind to the AH receptor, which is believed to mediate toxicity. Here, we determine effects of polychlorinated aromatic hydrocarbons in genotoxicity assays that score for DNA deletions by intrachromosomal recombination in vivo and in vitro. In this study, TCDD, Aroclor 1221, and Aroclor 1260 induced deletions in vivo in the mouse embryo; Aroclor 1221 and Aroclor 1260 induced deletions in yeast. We also show that the induced deletion events did not correlate with induction of AH hydroxylase. None of the tested compounds induced CYP1A-associated ethoxyresorufin-O-deethylase activity in mouse embryos or in vitro. These results clearly demonstrate a genotoxic activity of polychlorinated aromatic hydrocarbons in vitro and in vivo, which is independent of induction of cytochrome P450 activity. Because genetic instability and deletions may be mechanistically involved in carcinogenesis, these results may encourage further research to determine whether such genotoxic mechanisms may be useful for cancer risk assessment of polychlorinated aromatic hydrocarbons.

Gender differences in distal femoral morphology and the role of gender specific implants in total knee replacement: a prospective clinical study.

Gender differences in distal femoral morphology may affect femoral component fit using a standard range of prostheses. The clinical relevance of this is controversial. Standardised measurements were taken from the distal femora of 50 males and 50 females during total knee replacement (TKR). Corresponding measurements were taken from the respective gender specific and standard femoral components. No demographic differences were noted. Significant differences in both frequency and magnitude existed in the medial-lateral femoral component overhang between the sexes. In females, standard implants overhung at the anterior flange width (AFW) by >2mm in 24/50 (48%) and by >3mm in 17/50 (34%) (p<0.001). Also at the anterior medial-lateral width (MLA) 29/50 (58%) overhung by >2mm and 24/50 (48%) by >3mm (p<0.001). In males, standard implants overhung by >2mm in 1/50 (2%). In females, gender specific implants overhung by >2mm in 3/50 (6%). Females had a mean aspect ratio of 1.02 (0.82 to 1.35) and men 0.98 (0.79 to 1.19). Femoral component overhang can occur in females undergoing TKR and a gender specific implant would reduce the potential for medial-lateral overhang. Long term studies are awaited to quantify the clinical implications of overhang.