Which is more invasive-mini versus standard incisions in total hip arthroplasty?

In this study, interleukin-6 (IL-6), C-reactive protein (CRP), and haemoglobin levels were evaluated to compare the degree of surgical invasion between mini and standard incisions in total hip arthroplasty (THA). Sixty-two patients admitted for primary cementless THA were enrolled in this randomised study. The patients were allocated to have surgery through either a mini incision of <10 cm or a standard incision of 15 cm. In each group, inflammatory responses were evaluated by IL-6, CRP, and haemoglobin levels before operation and one day after operation. Significant differences were not found in IL-6, CRP, and haemoglobin levels between both groups. At six months after surgery, there were no significant differences in postoperative Harris hip scores or radiographic evaluations between both groups. In conclusion, a 5.0 cm difference in the skin incision to the hip joint seemed to have no influence on the degree of surgical invasion during THA.

How do porosity-inducing techniques affect antibiotic elution from bone cement? An in vitro comparison between hydrogen peroxide and a mechanical mixer.

BACKGROUND: Increasing the porosity of an antibiotic-loaded cement spacer increases the antibiotic elution, but the correlation between porosity and antibiotic elution is not well documented. The purposes of this study was to attempt new porosity-increasing methods and to investigate the correlation between antibiotic elution and both total and surface porosity. MATERIALS AND METHODS: Five types of antibiotic-loaded bone cement (ALBC) using 2 g cefazolin and 40 g cement were prepared. Other than manual mixing, hydrogen peroxide was used as a foaming agent and a mixing drill piece was used as a mechanical device to try to induce porosity when mixing the cement. Elution of antibiotic into phosphate-buffered saline was measured from 1 h to 1 week. Surface porosity was calculated from density values which were measured with a density kit and an electronic balance, while total porosity was quantified using micro-computed tomography. RESULTS: When a mixing drill piece was used to induce porosity, we observed a significant increasin antibiotic elution compared to a manually mixed ALBC. On the other hand, hydrogen peroxide reduced the elution significantly. Mild correlation between the total amount of cluted in 1 week antibiotic elution and total porosity was observed. CONCLUSIONS: In terms of improving elution, the mixing drill piece seemed to be efficient. A relationship between surface porosity and elution efficacy was not observed.

Antibiotic distribution in a bone cement spacer model.

PURPOSE: To mix high dose antibiotic powder to the bone cement more easily, Hanssen et al reported mixing the antibiotics with the cement during its liquid phase but made no comments about the relevance of cement viscosity and antibiotic distribution. The purpose of this study was to investigate the effect of the cement mixing technique and cement viscosity on the antibiotics distribution in a cement spacer model. METHODS: Thirty cylindrical models from three groups were examined. Group A was made by mixing the antibiotics with medium viscosity cement prior to adding the liquid monomer (traditional technique). Group B was made by mixing the antibiotics with medium viscosity cement during its liquid phase (Hanssen's technique). Group C was made by traditional technique with low viscosity cement. In all groups 2 g of tetracycline was used. Three 0.1 mm thick cross sections from each spacer model were examined under the fluorescent microscope. The fluorescent spots of tetracycline were calculated automatically in pixels. To evaluate the distribution of the antibiotics in the spacer model, we selected the cross section with the highest number of pixels and the one with the lowest number of pixels from each of the three cross sections and calculated the difference between them. The distribution disequilibrium was compared between group A and B, A and C. RESULTS: No significant difference was observed in either comparison. CONCLUSION: The Hanssen's mixing technique can be used when using high dose antibiotics, and either medium or low viscosity cement could be used in terms of antibiotic distribution.

L-shaped caliper for limb length measurement during total hip arthroplasty.

The existing methods of assessing limb lengthening during total hip arthroplasty (THA) are prone to error because the measurements are not parallel to the limb lengthening axis. In order to address this, we designed a caliper to estimate limb lengthening during THA and evaluated its accuracy compared with our previous device, the straight caliper. Limb lengths were measured in 100 patients. The L-shaped caliper was used in 50 cases and the straight caliper in 50. The correlation between intra-operative and post-operative radiographic measurements was significantly improved using the L-shaped device (p < 0.0001, r = 0.934). This method was extremely accurate in predicting changes in limb length due to surgery.

Cementless total hip arthroplasty using an autograft of the femoral head for marked acetabular dysplasia: case series.

PURPOSE: To assess the short-term outcome of cementless total hip arthroplasty involving an autograft of the femoral head in Japanese patients. METHODS: Cementless total hip arthroplasty with autogenous bone block grafting was performed on 18 hips in 15 patients with marked acetabular dysplasia. The resected femoral head was used as a graft for the superior-lateral region of the true acetabulum. Clinical outcome was correlated with the placement of the acetabular component, as revealed in radiographs. RESULTS: The 13 women and 2 men had a mean age of 60.2 years (range, 37.0-73.0 years) at primary surgery and a mean follow-up duration of 3.3 years (range, 2.0-5.3 years). According to the classification of Crowe, 4 hips were in group I, 3 were in group II, one in group III, and 10 in group IV. The mean Harris Hip Score preoperatively was 45.7 (range, 19-69) and that at follow-up was 82.5 (range, 44-100). All 15 cases showed a good clinical outcome. There were no major intra-operative complications in this series. The grafted bones united in all patients. Two patients need surgical revision because the lateral insertion of the acetabular component resulted in loosening of it. CONCLUSION: Medial insertion of the acetabular component provides satisfactory short-term outcomes. Lateral insertion of the acetabular component during total hip arthroplasty should be avoided in patients with marked acetabular dysplasia.

Quantitative anatomic characterisation of the pelvic brim to facilitate internal fixation through an anterior approach.

PURPOSE: To define the centre of the hip joint and the bone stock around the hip joint from the supra-acetabular portion or pelvic brim so as to avoid penetration of guidewire into the hip joint when performing internal fixation using the anterior approach. METHODS: A total of 42 cadavers were utilised. Measurements were completed before and after cutting the pelvis into 4 pieces. Before cutting the pelvis, the centre of the hip joint was measured on the pelvic brim. After cutting the pelvis, the bone stock around the hip joint was measured in each section. The pelvic brim and the anteroinferior iliac spine were utilised as guide points in the measurements, because these parameters could be determined during an anterior surgical procedure. RESULTS: On the pelvic brim, the reflected centre of the hip joint centre was located approximately 3.2 mm anterior to the distal edge of the anteroinferior iliac spine. The mean minimum bone stock of the pelvic brim was 14.0 mm in the centre of the hip joint section. CONCLUSION: This study described the anatomical reference points around the hip joint, and the ways in which they can be utilised to increase the safety of the anterior approach for internal fixation. It is important to define the centre of the hip joint from the supra-acetabular portion or pelvic brim, given that it is not visualised during surgery using an anterior approach.

Seroprevalence of canine dirofilariosis in South Korea.

Eight-hundred and forty eight dogs (480 females and 368 males) not on chemoprophylaxis were examined for Dirofilaria immitis infection from 2001 to 2002. Three-hundred and thirty nine (40.0%) of 848 samples tested with antigen detecting ELISA kits showed positive reaction for D. immitis antigen. More male (43.5%) than female (37.3%) dogs were affected in this study, although there was no significant difference between both groups. Chi2 analysis showed that female and male dogs of shoreline areas had higher significant prevalence than other areas (P<0.001), respectively. The mean overall positive rates of heartworm infection were 10.4% in dogs <2-year-old group, 46.5% in 2-4-year-old group, 48.4% in 4-6-year-old group and 50.3% in >6-year-old group. The older the age, the higher the prevalence of D. immitis infection in this study. Chi2 analysis revealed a significant higher prevalence in 4-6-year-old group (100%) of shoreline areas and in 2-4-old-year group (51.2%) of urban areas (Chungnam province), respectively (P<0.001), and also revealed that the over 6-year-old group (50.3%) in mean overall prevalence had the significant higher prevalence than other age group (P<0.001). In climate comparison, our data showed that shoreline areas (69.5%) had the significant higher prevalence than urban areas and mountain areas (P<0.001). This survey confirms that the prevalence of canine heartworm infection increases, and also that the prevalence in shoreline areas is higher than in other areas in South Korea.

Diurnal variation in microfilaremia in a cat experimentally infected with larvae of Dirofilaria immitis.

In five healthy mongrel female cats used, four cats (Cats 1-4) were experimentally inoculated with 100-123 larvae (L(3)) of Dirofilaria immitis. Cat 5 was an uninfected control. Only Cat 1 became microfilaremic on Day 201 after inoculation and the diurnal changes in the microfilaria population were monitored every 2 h for 24 h on Day 237 when a sufficient number of microfilaria were detected in the circulation. The maximum number of microfilaria in the blood (1,350/ml) occurred at 9:00 p.m. and then gradually decreased to the minimum of 300/ml at 7:00 a.m., indicating that the number of microfilaria shows a nocturnal sub-periodic pattern of diurnal rhythm even in peripheral blood of cats as an abnormal host. On postmortem examination, 10 live adult worms (three males and seven females) in Cat 1 and one live adult worm (one male) in Cat 2 were detected.

Viral activation of interleukin-15 (IL-15): characterization of a virus-inducible element in the IL-15 promoter region.

We identified an interferon regulatory factor motif (IRF-E) upstream of an NF-kappaB binding site in the interleukin-15 (IL-15) promoter. Since these two motifs are part of the virus-inducible enhancer region of the beta interferon promoter, we speculated that there might be similar responses of these two genes to stimuli such as viruses. To test this hypothesis, L929 cells were infected with Newcastle disease virus (NDV), which led to the induction of IL-15 mRNA and protein expression. Using IL-15 promoter-reporter deletion constructs, a virus-inducible region, encompassing IRF-E, NF-kappaB, and a 13-nucleotide sequence flanked by these two motifs, was mapped to the -295-to--243 position relative to the transcription initiation site. Using cotransfection studies, it was demonstrated that all three motifs were essential to achieve the maximum promoter activity induced by IRF-1 and NF-kappaB expression plasmids. The presence of a virus-inducible region in the IL-15 promoter suggests a role for IL-15 as a component of host antiviral defense mechanisms.

Immunohistochemical detection of p53 and c-myc proteins in canine mammary tumours.

The objectives of this study were to detect by immunohistochemical means, nuclear accumulations of p53 and c-myc proteins in mammary tumours of dogs. Moderate or intense p53 protein nuclear labelling was shown by each of five osteosarcomas. In contrast, focal immunoreactivity was shown by three of five adenocarcinomas and two of three malignant myoepitheliomas. Six benign mixed tumours and three myoepitheliomas showed no detectable immunoreactivity. On the other hand, three patterns of c-myc protein nuclear reactivity were observed in these tumours. Osteosarcomas, adenocarcinomas, malignant myoepitheliomas and myoepitheliomas showed intense or moderate reactivity. In benign mixed tumours, the epithelial component showed moderate or intense reactivity, and the myoepithelial component showed focal or moderate reactivity. These results demonstrated that p53 protein was expressed only in the osteosarcomas, but that c-myc expression was detectable in both the epithelial and myoepithelial components.

Seasonal periodical appearance of Hepatozoon canis gamont in the peripheral blood.

We investigated the appearance of gamonts in peripheral leukocytes of 13 Hepatozoon canis infected dogs from June 1990 to December 1992. In almost all the dogs, the numbers of gamonts increased from spring to autumn, and decreased from autumn to winter. Particularly in the dogs used for hare hunting, a large number of gamonts was detected from spring to autumn. This finding reveals that the gamont increases in number in the dog which ingested the infected ticks during the hunting season.