Poul Torben Nielsen

Epidemiology of Sprains in the Lateral Ankle and Foot

The epidemiology of sprains in the lateral ankle and foot was investigated in a prospective study at the casualty ward at Hillerad County Hospital. During one year, 766 patients were registered. The overall sprain incidence was 7/1000 person-years. The incidence was highest for young males. After the age of 40 years, the incidence was higher for women than for men. Most sprains were sustained during sport, but, with increasing age, other activities became dominant. Sixty-one percent of the lesions were located around the lateral ankle, and 24% were located on the lateral midfoot.

Fracture of ceramic femoral heads in total hip arthroplasty

Five cases of fractured ceramic heads occurring 1-2 years after primary hip arthroplasty are reported. All fractures occurred without significant trauma. As the mechanism of these failures has not been clarified, the authors have stopped using ceramic heads.

Comparison of trabecular metal cups and titanium fiber-mesh cups in primary hip arthroplasty: A randomized RSA and bone mineral densitometry study of 50 hips

Background Trabecular metal has shown promising results in experimental studies of bone ingrowth. Several clinical studies support these results. However, until now, no randomized clinical radiostereometric analysis (RSA) studies have been published. In this randomized RSA trial, we compared a new acetabular cup with a surface made of tantalum trabecular metal and a cup with a titanium fiber-mesh surface. Patients and methods Between 2004 and 2006, we operated 60 patients with noninflammatory hip arthritis. The patients were randomized to receive either an uncemented cup with a titanium fiber-mesh surface (Trilogy cup) or a cup with a trabecular tantalum surface (Monoblock cup). After 2 years, 50 patients had completed the study. The primary endpoint was cup migration within the first 2 years after surgery; the secondary endpoints were change in bone mineral density and Harris hip score at 3 months. Results Both cup types showed excellent fixation. RSA revealed minimal translation and rotation at 2 years. There was no statistically significant difference between the cup types with regard to translation. However, less rotation along the transverse axis was seen in the trabecular metal cups than in the fiber mesh cups: mean –0.01º (95% CI: –0.11 to 0.12) for trabecular metal cups and –0.60º (–0.72 to –0.48) for fiber-mesh cups (p = 0.04). The degree of periprosthetic bone loss was similar between the cup types in any of the regions of interest at 2 years of follow-up. 3 months postoperatively, we found a similar increase in Harris hip score in both groups: from around 50 to over 90. Interpretation We found promising early results concerning fixation of trabecular metal components to the acetabular host bone. However, we recommend a longer observation period to evaluate the outcome of this new cup design.

Faster recovery without the use of a tourniquet in total knee arthroplasty

Background and purpose— Tourniquet application is still a common practice in total knee arthroplasty (TKA) surgery despite being associated with several adverse effects. We evaluated the effects of tourniquet use on functional and clinical outcome and on knee range of motion (ROM). Patients and methods— 70 patients who underwent TKA were randomized into a tourniquet group (n = 35) and a non-tourniquet group (n = 35). All operations were performed by the same surgeon and follow-up was for 1 year. Primary outcomes were functional and clinical outcomes, as evaluated by KOOS and knee ROM. Secondary outcomes were intraoperative blood loss, surgical time and visibility, postoperative pain, analgesic consumption, and transfusion requirements. Results— Patients in the non-tourniquet group showed a better outcome in all KOOS subscores and better early knee ROM from surgery to week 8. No difference was detected at the 6- and 12-month follow-ups. Postoperative pain and analgesic consumption were less when a tourniquet was not used. Surgical time and visibility were similar between groups. Intraoperative blood loss was greater when not using a tourniquet, but no postoperative transfusions were required. Interpretation— This study shows that TKA without the use of a tourniquet results in faster recovery in terms of better functional outcome and improved knee ROM. Furthermore, reduced pain and analgesic use were registered and no intraoperative difficulties were encountered.

Histologic analysis of a retrieved hydroxyapatite-coated femoral prosthesis

A hydroxyapatite-coated hip hemi-prosthesis was retrieved from a 98-year-old osteoporotic woman 12 weeks after implantation. Histologic analysis revealed bone and fibrous tissue almost evenly distributed around the surface of the implant circumference. Quantitative histologic analysis showed that 48% of the hydroxyapatite surface was covered by bone. Fibrous tissue covered 30% of the prosthetic surface, and 20% of the surface had no tissue coverage. Scanning electron microscopy showed direct contact without any clear boundary between the newly formed bone and the hydroxyapatite ceramic.

Cementless total knee arthroplasty in unselected cases of osteoarthritis and rheumatoid arthritis

The authors reviewed 103 cementless AGC 2000 total knee arthroplasties in unselected cases of osteoarthritis and rheumatoid arthritis with a follow-up period of 3 years. Excellent or good clinical results were obtained in 96%. The median maximal flexion was 110 degrees. Two aseptic loosenings of the tibial components had been revised prior to this evaluation. Two other patients showed radiographic signs of tibial loosening but were asymptomatic. Undersizing of the tibial component predisposes to subsidence and loosening. One had septic tibial loosening planned for revision. Four had nonprogressive lucent lines beneath the tibial tray but were asymptomatic. No patellar or femoral component loosening was revealed. Undercorrection of preoperative varus deformity did not dispose to tibial loosening or radiolucency, nor influence the clinical result. In terms of survival of the prosthesis the cumulative success rate was 97.1%. When pain and radiographic loosening was also considered, the success rate was 90.7%. These results encourage uncemented use of this prosthesis, but emphasize the importance of good primary prosthetic fit at the tibial side.

Differences in zinc status between patients with osteoarthritis and osteoporosis

Zinc has been suggested to play an important role in the development of osteoporosis, whereas the influence of zinc on osteoarthritis has attracted much less attention. The aim of the study was to investigate and compare the zinc status and bone turnover, density, and biomechanical properties of osteoarthritic and osteoporotic patients. The study comprised 40 women who underwent hip replacement due to osteoarthritis or osteoporosis. Serum and urine zinc content, and bone resorption markers and serum bone formation markers were determined. The unaffected hip and the exarticulated affected femoral head underwent DEXA scanning. Bone biopsies were obtained from the femoral heads and the biomechanical properties were determined. The biopsies were ashed and the bone zinc content was ascertained. Osteoarthritic patients had significantly higher serum zinc concentrations and lower urine zinc concentrations than osteoporotic patients, whereas the bone zinc content did not differ. The zinc status was not found to be a predictor for the bone strength. In conclusion, the finding that the zinc status of osteoporotic patients is significantly different from that of osteoartritic patients is new and supports the view that osteoporosis and osteoarthritis rarely occur in the same individual.

Cementless total knee arthroplasty in rheumatoid arthritis: A report on 51 AGC knees followed for 54 months

Fifty-one primary consecutive cementless AGC 2000 (Anatomically Graduated Components, Biomet, Warsaw, IN) total knee arthroplasties were performed during 1985 through 1990 in 40 patients with rheumatoid arthritis. Forty-one knees (32 patients) were available for clinical and radiologic follow-up analysis after 24 to 76 months (median, 54 months). There was no pain in 33 knees and mild pain in the rest. Median range of motion was 110 degrees (range, 50 degrees-130 degrees). Median knee score was 90 (range, 71-97), and all knees were rated good or excellent. Radiolucencies greater than 1 mm were found under five tibial components, but no obvious migrations were seen. One tibial component was revised due to aseptic loosening. The cumulative success rate after 4 to 5 years was 97% (lower limit of 95% confidence interval, 91.8%). The medium-term results are considered to compare favorably with reported cemented series.

ACUTE MIDTARSAL SPRAINS : FREQUENCY AND COURSE OF RECOVERY

In a prospective consecutive registration of 711 ankle inversion sprains, the dorsal ligaments and capsule of the midtarsal joints were involved in 237 of the cases (33%), and in 172 cases (24%) only these joints seemed to be injured. A total of 162 isolated midtarsal injuries and 161 cases of isolated lateral talocrural lesions selected at random were followed using questionnaires 1, 3, 6, 9, and 12 months after injury. The frequencies of pain after 1 month and swelling after 1 and 3 months were significantly lower in isolated dorsal midtarsal sprains compared with isolated lateral talocrural sprains. At the following controls, frequencies of both pain and swelling were the same for both groups. Functional instability appeared with the same frequency in both groups during the 12 months of follow-up. Regarding the social impact of the sprains, absence from work and sports did not differ between groups. When avulsions were present in midtarsal injuries recovery was slow, with two thirds of the patients experiencing pain after 6 months. We conclude that the dorsal midtarsal sprain is a common entity with a course of recovery and a frequency of residual symptoms very like the lateral talocrural lesions.

DXA Scanning of Acetabulum in Patients With Cementless Total Hip Arthroplasty

The aim of this study was to evaluate the reproducibility of bone mineral density (BMD) measurements of the periprosthetic bone in patients with hemispherical acetabular cups in cementless total hip arthroplasty (THA). Thirty patients were treated for primary osteoarthrosis with cementless THA. Dual-energy X-ray absorptiometry (DXA) scanning was performed with a pencil-beam bone densitometer (Norland XR-36). Accuracy and reproducibility was determined by double measurements of BMD in four regions of interest (ROI). The influence of patient postures including various pelvic inclination angles was evaluated as well. Pitman test for a combined netROI revealed a standard deviation ratio of 3.2 for the anterio-posterior scans related to the lateral position. The Wilkinson ROIs showed a high intraobserver agreement. With pelvic tilt increasing until 20 degrees , the precision of DXA scanning decreased. In conclusion, reproducibility of DXA scanning was high. This study demonstrated that the patients can be scanned in the supine position, and BMD measurement of the periacetabular bone can be performed using the Wilkinson model with four rectangular ROIs.