Ole P. Kristensen

SURVIVORSHIP ANALYSIS OF CEMENTED TOTAL CONDYLAR KNEE ARTHROPLASTY: A LONG-TERM FOLLOW-UP REPORT ON 348 CASES

Survivorship analysis was used in the evaluation of 348 consecutive primary total condylar knee arthroplasties (total knee arthroplasties) performed on 253 patients in a 27-month period, with a maximum follow-up period of 12 years. The diagnosis was osteoarthrosis in 184 cases and rheumatoid arthritis in 164 cases. Ten patients (10 total knee arthroplasties) were lost to follow-up evaluation. The endpoint was defined as prosthesis not in situ. The variables considered were age, sex, body mass index, and diagnosis. The overall cumulative survival rate was 92%. The survival rate of the osteoarthrosis group was significantly higher (97%) than that of the rheumatoid arthritis group (87%). None of the other variables affected survival rate significantly.

Indomethacin for prevention of heterotopic ossification: A randomized controlled study in 41 hip arthroplasties

The effect of indomethacin 25 mg 3 times daily during the first 2 postoperative weeks in preventing heterotopic bone formation after cemented total hip arthroplasty was investigated in a randomized, double-blind and placebo-controlled clinical trial on 57 patients. 16 patients were secondarily excluded, leaving 19 patients in the indomethacin group and 22 patients in the placebo group. Evaluated from the 3-month radiographs, 18/19 indomethacin patients developed either no or only the milder Grade 1 ossification. In contrast, 11/22 placebo patients developed Grade 2 or 3 ossifications. Our observations favor indomethacin prophylaxis for 2 weeks in cemented arthroplasty of the hip.

Long-term results of total condylar knee arthroplasty in rheumatoid arthritis

We have reviewed at an average period of ten years the results of 71 consecutive primary arthroplasties with the Insall-Burstein total condylar knee prosthesis in patients with rheumatoid arthritis. Their mean age at surgery was 52 years (24 to 72). At follow-up the overall results (Hospital for Special Surgery knee rating score) were excellent or good in 77%, fair in 11% and poor in 11%. There was residual pain in only 5% of patients with prostheses in situ; 58% could walk more than 500 m, and the median range of motion was 108 degrees. Eight knees had been revised. Five underwent arthrodesis because of deep infection and three needed revision arthroplasty for mechanical loosening. The crude survival rate of the arthroplasties was 89%. The presence of radiolucency around the tibial component correlated significantly with the severity of residual pain.

Public Versus Private Provision of Governmental Services: The Case of Danish Fire Protection Services

Comparisons of the costs of private and public production of the same service are of interest because governmental services do not have to be produced by public institutions. The production may be contracted out to private companies. The paper presents an empirical analysis of costs of private and public provision of fire protection in Denmark. Strict state regulation of municipal fire protection services makes the costs of public and private production more comparable than is often the case. The findings show substantial cost differences in favour of private production. In the discussion, this difference is primarily attributed to economies of scale and competition from alternative sources of supply related to private production of fire protection services.

The press-fit Kinemax knee arthroplasty. High failure rate of non-cemented implants

We report the results of 75 consecutive primary press-fit Kinemax arthroplasties with an average follow-up of 14 months (three to 28). We reviewed 26 cemented and 49 non-cemented tibial components implanted into 72 patients (30 men and 42 women, median age 70 years). At the latest follow-up the overall evaluation (Hospital for Special Surgery knee rating scale) for cemented cases was excellent in 54%, good in 42% and poor in 4%. No cemented prosthesis loosened. Of the non-cemented cases 55% were excellent, 23% good, and 2% fair. Ten tibial implants (20%) loosened and required revision. Residual pain marred the result in 24% of the non-cemented prostheses and in 4% of the cemented group. We do not recommend the press-fit, smooth-surfaced Kinemax prosthesis for non-cemented use.

Isolation, crystallization and X-ray analysis of the quaternary complex of Phe-tRNAPhe, EF-Tu, a GTP analog and kirromycin

Kirromycin inhibits bacterial protein synthesis by acting on elongation factor Tu (EF‐Tu). Complexes of the antibiotic, Phe‐tRNAPhe, the guanosine triphosphate analog GDPNP, and mesophilic (Escherichia coli), as well as thermophilic (Thermus thermophilus) EF‐Tu were isolated. Crystallization was achieved at 4°C, pH 6.4, using ammonium sulphate as precipitant. Crystallographic data were recorded at cryogenic temperature on crystals exposed to synchrotron radiation. Crystals of the thermophilic complex are based on a rhombohedral lattice with cell dimensions of 137.3 Å, and angles of 54.0°. Although related, these cell parameters are different from those found in the crystals of the recently solved structure of the ternary complex of Phe‐tRNAPhe, GDPNP, and Thermus aquaticus EF‐Tu (Nissen, P., Kjeldgaard, M., Thirup, S., Polekhina, G., Reshetnikova, L., Clark, B.F. and Nyborg, J. (1995) Science 270, 1464–1472 [1]), possibly indicating some allosteric effect caused by kirromycin. Crystals of the mesophilic complex belong to the cubic space P432, with cell axis of 196.26 Å. In both cases, the crystals contain one complex per asymmetric unit.

Total condylar arthroplasty for gonarthrosis: A prospective 10-year study of 138 primary cases

The results of 138 consecutive primary Insall-Burstein arthroplasties with an average observation period of 10 (9-11) years were assessed. Mean age at surgery was 71 (30-81) years. The patients were evaluated clinically, using the Hospital for Special Surgery knee rating scale, and radiographically, according to the radiolucency score of the Knee Society. At latest follow-up, the overall evaluation of the patients who completed the study was excellent or good in 86 percent, fair in 8 percent and poor in 6 percent. Residual functional pain was recorded in 12 percent of cases with prostheses in situ. An ability to walk more than 500 m was found in 62 percent. The median range of motion was 104 degrees. Arthrodesis was performed on 2 knees due to deep infection. There were 14 cases with substantial radiolucency around the prosthesis, but none of these patients had severe functional pain. The crude prosthetic survival rate was 98 percent. A correlation was found between the radiolucency score and both the total score and the intensity of the residual functional pain.