Search PubMed⌕ Search

Biomedical subjects

L Zichner

Publications and source records attributed to L Zichner.

At least 55 records · Page 3Linked to original sources
PubMed1976

Animal studies on bone ingrowth kinetics of ceramic material under dynamic stress.

Two of the primary problems of implants in use today result from the materials used in their construction (metal and polyethylene) and from the necessary additional fixation with bone cement. In order to alleviate these well known difficulties, we studied ceramic material (99.7% Al2O3 with 0.25% MgO) which exhibits several advantages in these areas, but has a diminished bending strength. To take advantage of the ceramic material, we tested a cement-free implantation which should allow unhindered growth of bone tissue to or into the material. In particular, the interface relationship under load bearing was investigated. The course of the tissue differentiation and ingrowth on the surface of the ceramic implants under dynamic stress, was studied by a specifically disegned distance-spacer. These were tested on the femur of foxhounds and sheep, as well as by use of temporary immobilization. Histological investigations in intervals of 4 weeks showed the course of the development of the interface tissue. After removal of the binding materials, the behavior of the implant support is studied in 4-week intervals with free load bearing. Radiological and histological development studies are shown. The results we obtained implicate the use of ceremic impants. But the application in humans still seems to be problematic, as there is a need for designs which are loaded by pressure only.

Aluminum↗
PubMedDate not supplied

[Dose-dependent prevention of early periprosthetic bone loss by alendronate].

AIM: Periprosthetic bone loss occurs in the first six months after total hip arthroplasty (THA) and is felt to be largely the result of initial operative irritation, immobilization, and stress shielding. This study (a prospective, randomized, open, blinded endpoint evaluation) aims at preventing bone loss around the stem with an oral bisphosphonate. METHOD: 66 healthy subjects with uncemented THA and low lumbar bone mass density (BMD) (negative T score) were treated post-operatively with alendronate as follows: n = 21 with 10 mg/d for 10 weeks (A), n = 21 20 mg/d for 5 weeks (B), n = 24 no treatment for controls (C). The periprosthetic BMD in the Gruen zones (ROI) was measured after the 2nd, 4th, 6th, and 12th month by DEXA as a percentage of the value measured one week after surgery. RESULTS: In C, there was significant bone loss in all ROI during the first months and a deficit of 29 % in ROI 7 following one year. In B, bone loss was completely prevented up to the second month, in ROI 7, a significant difference in comparison to C was registered for the entire year. In A, significant bone loss reduction during 12 months was seen. CONCLUSION: Alendronate, therefore, is capable of preventing initial periprosthetic bone loss. A dosage of 20 mg/d is required initially with daily treatment lasting at least 10 weeks.

Absorptiometry, Photon↗
PubMedDate not supplied

[Good results with a cemented titanium stem after 7-9 years].

AIM: Because of partially ver y controversial results in cemented hip stem replacements made of titanium alloy we investigated in our own patients the mid-term survival of the "Euroform"-stem. This stem is anatomically designed for cemented fixation, made of Ti (6)Al (4)V. METHOD: Within a period between 1990 and 2000 we implanted 2,141 Euroform-prostheses. The course of 103 patients which were operated between April 1990 and April 1992 was followed up. 9 patients died in the meantime and 8 could not be reached. Of the remaining 86 patients we could examine 73 patients with 79 prostheses (87 %). Investiagtion included a questionnaire and clinical and radiological examination to create the Harris-hip-score. The follow-up was 7-9 years, with an average of 94 months. RESULT: Of those 79 prostheses, revision surgery was performed for septic loosening in three cases and for aseptic loosening in two cases. Radiologically one stem was found to be loosen. This means that for aseptic loosening we had a revision rate for aseptical femoral loosening of 2.5 % after 94 months with a mean Harris-hip-score of 84 points. Good or excellent results were found in 82 %, fair results in 9 % and poor results in 9 %. CONCLUSION: The "Euroform" prosthesis is a cemented titanium alloy stem that has in contrary to some other published studies good mid- to long-term results.

Adult↗
PubMedDate not supplied

[The epiphysis].

Explore the source record for details and available documents.

Epiphyses↗