Tc-99m-labeled endothelin derivative for imaging of experimentally induced atherosclerosis.

OBJECTIVE: to characterize the potential of an endothelin derivative labeled with technetium-99m (Tc-99m) for the imaging of experimentally induced atherosclerosis. METHODS: neointima of different cellularity and severity of stenosis was induced in 32 rabbits by balloon denudation followed by distinct dietary regimens and drug application. Angiograms and scintigrams after injection of the Tc-99m-labeled endothelin derivative were obtained. The aorta was dissected for autoradiography, sudan-III-staining, morphometry, and immunohistology. RESULTS: the lesions induced could be detected in vivo (whole body scintigram) in all the animals 15 min after the injection of the Tc-99m endothelin derivative. Autoradiography revealed a strong relationship between tracer accumulation and sudan-III-staining of lesions. Accumulation of the endothelin derivative correlated with the number of neointimal smooth muscle cells (SMC), but not with the number of medial SMC, neointimal macrophages, and neointimal area. CONCLUSIONS: the results indicate that in vivo imaging of atherosclerosis with an endothelin derivative is a feasible method of detecting and characterizing atherosclerotic arterial wall lesions at early stages.

Impaction bone-grafting before insertion of a femoral stem with cement in revision total hip arthroplasty. A minimum two-year follow-up study.

Impaction bone-grafting was performed before insertion of a collarless, polished, tapered femoral stem with cement in thirty-four revision total hip arthroplasties (thirty-four patients) that were done because of aseptic loosening. The average duration of follow-up was thirty months (range, twenty-four to forty-two months). The operation was the initial revision in twenty-eight patients (82 per cent). Twenty-two patients (65 per cent) also had revision of the acetabular component. Complications included four intraoperative and two postoperative fractures of the femur as well as one dislocation (at one month). Two patients (6 per cent) needed a repeat revision of the femoral stem because of aseptic loosening at twenty-six and thirty-six months postoperatively. Both of these patients had an associated fracture of the femur (one was intraoperative, and the other was postoperative). Subsidence was common (thirteen patients; 38 per cent) and averaged 10.1 millimeters (range, four to thirty-one millimeters). Although the study group was relatively small, with the numbers available subsidence was not found to be associated with the preoperative or postoperative hip score, segmental or cavitary femoral defects, femoral ectasia, intraoperative fracture of the femur, strut-grafting, trochanteric osteotomy, or varus position of the femoral component. Incorporation of the allograft into the trabecular bone and secondary remodeling were noted radiographically in thirty-two (94 per cent) and fourteen (41 per cent) of the patients, respectively, often within one year. Although the duration of follow-up was relatively short, no localized resorption of the allograft occurred and cortical repair was noted in one patient at three years. At the most recent follow-up evaluation, the Harris hip scores had improved from a preoperative average of 51 points (range, 32 to 90 points) to an average of 87 points (range, 65 to 100 points) and twenty-eight patients (82 per cent) had no or only slight pain. Despite the satisfactory early clinical results, we remain concerned about the high rate of fracture of the femur and the rate and extent of subsidence of the femoral component. On the basis of the worrisome findings after this two-year period, we recommend that impaction bone-grafting be used only when proximal femoral osteopenia is so severe that stability cannot be obtained with insertion of a long-stemmed femoral component without cement. In that setting, impaction bone-grafting may be considered instead of implantation of a massive proximal femoral allograft in combination with insertion of a femoral component with cement.

Total knee arthroplasty after high tibial osteotomy. A comparison study in patients who had bilateral total knee replacement.

BACKGROUND: The outcome of total knee replacement after high tibial osteotomy remains uncertain. We hypothesized that the results of total knee replacement with or without a previous high tibial osteotomy are similar. METHODS: The results of a consecutive series of thirty-nine bilateral total knee arthroplasties performed with cement at an average of 8.7 years after unilateral high tibial osteotomy were reviewed. There were twenty-seven men and twelve women. Preoperatively, the knee scores according to the system of the Knee Society were similar for all of the knees; however, valgus alignment and patella infera were more common in the knees with a previous high tibial osteotomy. Bilateral total knee replacement was staged in seven patients and was simultaneous in thirty-two patients. The results of the total knee arthroplasties were retrospectively reviewed with respect to the knee and function scores according to the system of the Knee Society, the radiographic findings, and the complications. RESULTS: Intraoperatively, no notable differences were identified in the number of medial, lateral, or lateral patellar releases required. However, less lateral tibial bone was resected in the group with a previous high tibial osteotomy (average, 3.3 millimeters) than in the group without a high tibial osteotomy (average, 7.5 millimeters). The average duration of follow-up was 7.5 years (range, three to sixteen years) in the group with a previous high tibial osteotomy and 6.8 years (range, two to ten years) in the group without a high tibial osteotomy. At the time of the final follow-up, the knee and function scores were similar for the two groups (89.0 and 81.0 points, respectively, for the group with a previous high tibial osteotomy, and 89.6 and 83.9 points, respectively, for the group without a high tibial osteotomy). Although more knees were free of pain in the group without a previous high tibial osteotomy (thirty-six) than in the group with a previous osteotomy (thirty-three), this difference was not found to be significant with the numbers available (p = 0.4810). Knee alignment and stability, femoral and tibial component alignment, and range of motion also were similar in both groups postoperatively. One allpolyethylene tibial component was revised in the high tibial osteotomy group. Two knees in each group required manipulation. There were no deep infections. CONCLUSIONS: While patients with a previous high tibial osteotomy may have important differences preoperatively, including valgus alignment, patella infera, and decreased bone stock in the proximal part of the tibia, the present study suggests that the clinical and radiographic results of primary total knee arthroplasty in knees with and without a previous high tibial osteotomy are not substantially different. In our relatively small group of patients, the previous high tibial osteotomy had no adverse effect on the outcome of the subsequent total knee replacement.

Polyethylene wear in uncemented acetabular components.

We measured polyethylene wear in 231 porous-coated uncemented acetabular cups. We divided the hips into two groups according to the fixation of the femoral component, by cementing (n = 97) or press-fit (n = 134). Follow-up was from three to five years. The patients in two sub-groups were matched for weight, diagnosis, sex, age and length of follow-up. The linear wear rate of cups articulated with uncemented femoral components (0.22 mm/year) was significantly higher than the wear rate (0.15 mm/year) of cups articulated within cemented femoral components (p < 0.05). These results can be compared with previously reported wear rates of 0.08 mm/year for cemented all-polyethylene cups and 0.11 mm/year for cemented metal-backed cups. The higher wear rates of uncemented arthroplasties could jeopardize the long-term results of this type of hip replacement.

Intra-articular morphine and/or bupivacaine after total knee replacement.

The postoperative analgesic effects of intra-articular injections of bupivacaine and/or morphine were examined prospectively in 437 patients who had total knee replacement for osteoarthritis. They were divided randomly into four groups. Group I received 10 mg of morphine (1 ml) and 9 ml of saline, group II received 10 ml of bupivacaine (2.5 mg/ml), group III received 10 ml of saline, and group IV received 10 mg of morphine (1 ml) and 9 ml of bupivacaine (2.5 mg/ml). All analgesics administered in the first 24 hours after operation were recorded. The patients rated their pain on the McGill-Melzack scale at 1, 6, 12 and 24 hours. No significant differences were found between any of the groups in the use of Demoral and/or Toradol in 24 hours, the length of stay in hospital or the pain rating at 1, 6, 12 or 24 hours. Patients in groups I and IV, whose injections included morphine, used significantly more morphine in the first 24 postoperative hours than did groups II or III.

Intra-operative findings in varus osteoarthritis of the knee. An analysis of pre-operative alignment in potential candidates for unicompartmental arthroplasty.

Interest in unicompartmental knee arthroplasty (UKA) for the treatment of medial compartment osteoarthritis has increased in recent years with apparent improvement in the long-term results. This is a result of improved surgical technique, patient selection, and implant design. In an effort further to improve patient selection we analysed the relationship between the pre-operative alignment of the knee and the anatomical findings at the time of surgery. We compared these findings with the indications for UKA. From 4021 total knee arthroplasties we compared intra-operative observations with the pre-operative clinical data in order to identify knees with isolated, medial, compartment changes, which would have been ideal candidates for UKA. We found that only 247 of the knees (6.1%) met anatomical qualifications for isolated, medial, unicompartmental osteoarthritis, and of these, only 168 (4.3%) met clinical standards ideal for UKA. Preoperative alignment showed a significant relationship with patterns of disease. Logistic regression revealed a relationship between pre-operative alignment and intraoperative findings resembling a Gaussian distribution. Patients with a pre-operative varus alignment of 7 degrees were slightly more likely to be selected for UKA. But the further the anatomical alignment in either direction varies from 7 degrees of varus, the more unlikely it is for the knee to exhibit a disease pattern of isolated, medial, unicompartmental osteoarthritis.

Long-term deterioration of joint evaluation scores.

We investigated the long-term changes in the Harris Hip and Knee Society scores (HSS and KSS) to determine whether they result from overall functional decline rather than actual changes in the condition of the prosthesis. The HHS for 106 total hip arthroplasties with a minimum follow-up of ten years, no medical complications after operation and no evidence of radiological loosening, and the KSS for 264 total knee arthroplasties with a minimum follow-up of 12 years and no medical complications after operation or signs of radiographical loosening were evaluated. There were statistically significant drops in the functional scoring components of the joint evaluation systems despite no loosening of the prostheses or other significant medical complications. The HHS declined at an average of 0.67 points per year from between three and ten years after operation (p < 0.0001). Contributing to this were deterioration in gait and limp (p < 0.0004), the use of support aids (p < 0.0001), the distance walked (p < 0.0001) and the ability to climb stairs (p < 0.0455). The functional component of the KSS declined significantly at an average 0.88 points per year betwen the third and 12th years (p < 0.0001). There were significant declines in every component of the functional score including the distance walked (p < 0.0001), the ability to climb stairs (p < 0.0001) and the use of support aids (p < 0.0001). The knee score component of the KSS did not decline significantly (p < 0.9750). The combination of functional and pain scores within the HHS system leads to an inaccurate decline in the entire score. The decline of HHS and Knee Society functional scores in total joint arthroplasties, in the absence of implant-related problems, suggests that deterioration in the functional capacity of ageing patients is an important factor in longitudinal studies using these scoring systems.

Radiological factors influencing femoral and acetabular failure in cemented Charnley total hip arthroplasties.

We have made a retrospective review of 185 cemented Charnley total hip arthroplasties performed between 1970 and 1974 to determine the relationships between radiological variables and failure of the femoral and acetabular components. We measured the acetabular wear, the orientation of the cup, the thickness and consistency of acetabular and femoral cement mantles, radiolucency and femoral alignment. The mean follow-up was for 11.7 years. Femoral loosening was demonstrable radiologically in 15 hips (8.1%), ten (5.4%) of which were revised during the period of follow-up. Only when the first postoperative radiograph showed a thin cement mantle in Gruen zone 5 was there a significant association with failure of the femoral component. There were 12 loose acetabular components (6.5%), nine (4.8%) of which were revised. When the initial radiograph after operation showed radiolucency in DeLee and Charnley zone 1, the incidence of acetabular loosening was 28.21%. If such radiolucency was not present, the incidence of acetabular loosening was only 0.69%. Our findings emphasise the importance of careful cementing.

Maximizing cost-effectiveness while minimizing complications in total hip replacement.

Between July 1989 and June 1994, a consecutive series of 651 cemented total hip arthroplasties were performed in 577 patients using relatively inexpensive implants and standardized surgical and postoperative protocols. We set out to determine what effect these cost-saving measures have on the overall success and complication rate after total hip replacement surgery. Surgical results remained excellent, and perioperative, early, and late complications, including infection, loosening, and revision hip surgery, remained minimal, indeed, below usual complication rates. We concluded that cost-effective measures can be implemented while maintaining the overall excellent results of hip replacement surgery without the risk of increasing complication rates.

Intraarticular trochanteric wire migration following bilateral total hip arthroplasty. A case report.

A 64-year-old man underwent bilateral simultaneous total hip replacement and experienced articular interposition of a wire fragment in the right hip joint 3 years postoperatively. Because of destructive wear of the acetabulum, this eventually required revision total hip arthroplasty 12 years after the original surgery.

Total hip arthroplasty. Can the patient play sports again?

To analyze the effect of athletic involvement on total hip replacements, a questionnaire was sent to all of our total hip patients with at least a 3-year follow up. Patients were asked to list the type, degree, and frequency of sports participation before and after surgery, along with any problems they encountered upon returning to active sports. The patients who responded were then placed in one of two groups, participant or non-participant, for each sport we encountered, and were statistically compared with respect to clinical analysis. The population showed a significant decrease in all forms of activity after surgery, except bicycling; yet more returned to an active sport than did not. No correlation existed between involvement in a sport and the variables we tested. We concluded that intelligent participation in activities such as walking, golf, or bowling where no excess load was placed on the total hip, had no influence on the outcome of a total hip replacement.

Femoral head size: variation among manufacturers.

Nine manufacturers were contacted for their specific femoral head diameters of the 22 mm, 28 mm, and 32 mm femoral components. The 22 mm heads averaged .869 in. (+/- .005) and 100% were within 1 standard deviation; however, the standard deviation was large. The 28 mm heads averaged 1.101 in. (+/- .002), and 89% were within 1 standard deviation. The 32 mm heads averaged 1.258 in. (+/- .002), and 78% were within 1 standard deviation. It seems that when a 28 mm or 32 mm femoral head is used, different femoral and acetabular components by different manufacturers can be intermixed. However, when changing a 22 mm femoral head, the manufacturer should possibly be notified and an attempt to use the same manufacturer is preferable.

Meeting increased demand for total knee replacement and follow-up: determining optimal follow-up.

The strain on clinic and surgeon resources resulting from a rise in demand for total knee replacement (TKR) requires reconsideration of when and how often patients need to be seen for follow-up. Surgeons will otherwise require increased paramedical staff or need to limit the number of TKRs they undertake. We reviewed the outcome data of 16 414 primary TKRs undertaken at our centre to determine the time to re-operation for any reason and for specific failure mechanisms. Peak risk years for failure were determined by comparing the conditional probability of failure, the number of failures divided by the total number of TKRs cases, for each year. The median times to failure for the most common failure mechanisms were 4.9 years (interquartile range (IQR) 1.7 to 10.7) for femoral and tibial loosening, 1.9 years (IQR 0.8 to 3.9) for infection, 3.1 years (IQR 1.6 to 5.5) for tibial collapse and 5.6 years (IQR 3.4 to 9.3) for instability. The median time to failure for all revisions was 3.3 years (IQR 1.2 to 8.5), with an overall revision rate of 1.7% (n = 282). Results from our patient population suggest that patients be seen for follow-up at six months, one year, three years, eight years, 12 years, and every five years thereafter. Patients with higher pain in the early post-operative period or high body mass index (≥ 41 kg/m(2)) should be monitored more closely.

The role of the posterior cruciate ligament in total knee replacement.

OBJECTIVES: The purpose of this study was to examine the effect of posterior cruciate ligament (PCL) retention, PCL recession, and PCL excision during cruciate-retaining total knee replacement. METHODS: A total of 3018 anatomic graduated component total knee replacements were examined; 1846 of these retained the PCL, 455 PCLs were partially recessed, and in 717 the PCL was completely excised from the back of the tibia. RESULTS: Clinical scores between PCL groups favored excision for flexion (p < 0.0001), and recession and retention for stairs (p < 0.0001). There was a mild difference in long-term all-cause aseptic survivorship between PCL-retained (96.4% at 15 years) combined with PCL-recessed groups (96.6% at 15 years) when compared with the PCL-excised group (95.0% at 15 years) (p = 0.0411, Wilcoxon; p = 0.0042, log-rank), as well as tibial or femoral loosening, which reported prosthesis survival of 97.8% at 15 years for PCL-retained knees, 98.2% for recessed knees, and 96.4% for excised knees (p = 0.0934, Wilcoxon; p = 0.0202, log-rank). CONCLUSIONS: Despite some trade off in clinical performance, if the PCL is detached at the time of operation, conversion to a posterior-stabilised prosthesis may not be necessarily required as long as stability in the anteroposterior and coronal planes is achieved.

[Artificial insemination in pigs: study of conception conditions with use of 2 inseminations in heat with about 24 hours interval]. / Kunstig saedoverføring på svin: undersogelse af konceptions-forholdene ved anvendelse af to insemineringer i brunsten med ca. 24 timers interval

140 sows and gilts of Danish Landrace were inseminated twice per heat with an interval of approximately 24 hours. Half of the females had their first insemination with semen of Danish Landrace and their second insemination with semen of Yorkshire, the other half vice versa. 114 females became pregnant. At farrowing the number of offspring of Danish Landrace and/or Danish Landrace X Yorkshire per sow/gilt was registrated. The results have been set out in tables I and II, from which it can be seen, that 59% conceived only after first insemination, 18% only after second insemination and 23% after both first and second insemination. In the last group 52% of the offspring were from the first insemination and 48% from the second insemination. In the sows no increase in av. litter size after two inseminations was found. The results are discussed and apparent discrepancy with earlier results is explained with a presumbably existing competition in the female genital tract between sperms from two inseminations at different times in the heat, resulting in ageing of the first inseminated sperms.

[A.I. in pigs: influence of boar seminal plasma on breeding efficiency of diluted boar semen (author's transl)]. / Kunstig saedoverføring på svin: saedplasmas indflydelse på ornesaeds befrugtningseffektivitet

Ejaculates from six boars of Danish Landrace were divided into four parts, I, II, III and IV which were treated in the following way: I was diluted 1:4-1:6 with EDTA-diluter, and filled into glass vials (single doses). II was centrifugated at 1800-2000 r.p.m. in 12-15 min.; the centifugate was resuspended in the supernatant and diluted as indicated under I. III and IV were centrifugated at 1800-2000 r.p.m. in 12-15 min. The supernatant was removed by aspiration and the centrifugate diluted with as much EDTA-diluter necessary to produce the same no, of doses of 10 ml as was produced from I and II respectively. The diluted semen was stored at 18-20 degrees C and used on the day of collection. Just before insemination the semen from I, II and III was diluted with IVT-diluter to a final volume of 75 ml. Semen from IV was diluted to the same volume with IVT-diluter with the addition of 50% boar seminal plasma, procured by centrifugation of ejaculates from other boars of the A.I. Centre, and stored at divided by 20 degrees C until use. The results have been set out in Table I. Inseminations with semen from I and II resulted in pregnancy rates of 84,6% and 86,3% and average litter sizes of 10,3 and 10,1 for sows and 9,1 and 9,6 for gilts; inseminations with semen from III and IV resulted in pregnancy rates of 78,9 and 78,2% and average litter sizes of 10,5 and 10,7 for sows and 10,0 and 8,7 for gilts. None of the differences in pregnancy rates between groups were significant. The findings were: 1. By insemination with initially diluted semen without seminal plasma a tendency to a decline in pregnancy rates could be demonstrated. 2. The decline persisted after the addition of 50% boar seminal plasma to the diluter used for the final dilution just before insemination.

PIP: Results are reported of an experiment which researhes the effect that addition of seminal plasma to diluted semen can have on the rate of fertilization. the ejaculates from 6 boars were divided into 4 groups. Group 1 was used as a control, and was dilated 1:4-1:6 with EDTA; this semen had an 84.6% impregnantion rate. The rest of the ejaculate was centrifuged at 1800-2000 rpm for 12-15 minutes. Group 2 consisted of the centrifugate resuspended in the supernatent; this group had an 86.3% impregnation rate. Group 3 consisted of the centrifugate dilated only with IVT; this group had an impregnation rate of 78.9%. Group 4 consisted of the centrifugate combined with IVT and 50% boar seminal plasma; this group had a 78.2% impregnantion rate. There were no significant differences between the pregnancy rates or the litter sizes among any of the groups. boar seminal plasma does not seem to have a positive effect on the fertilization rate of diluted semen.

[Influence of semen collection on breeding efficiency of a.i. boars (author's transl.)]. / Saedopsamlingshyppighedens indflydelse på a.i. orners saedproduktion og befrugtningseffektivitet

Based upon semen records and 30-60 days non-return percentages from 171 boars of Danish Landrace the influence of frequency of semen collection on semen production and breeding efficiency was investigated. Semen production was expressed by the number of doses of 2.0 times 10-9 motile sperms per ejaculate.