PURPOSE: Are the results of cemented titanium hip arthroplasty as bad as described in literature? We present the 10-year results of a cemented mild grid blasted Titanium-Aluminium-Vanadium Stem in Total-Hip-Arthroplasty. METHODS: The clinical and radiological reexamination was documented in standardized questionnaire in which several scores were integrated. All X-rays were stored and analysed by a special hardware and software computer system. RESULTS: 35% of all patients could be reexamined both clinically and roentgenologically. 71 patients were male (mean age 56.1 years) and 130 female (mean age 59.3 years). The average follow-up period was 11 years and 4 months. The mean Merle d'Aubigné hip score increased from 10.5 to 16.0 points at the follow-up evaluation. Radiolucent lines were according to the zones of Gruen seen in 1% to 22% depending on the zone and the size of the femoral component. 18 reoperations of the femoral component (2.9%) had to be performed. The survivorship analysis (Kaplan-Meier) showed a 95.4% survival of the femoral component after 10 years. CONCLUSION: Our findings with a cemented mild grid blasted Titanium-Aluminum-Vanadium stem demonstrate excellent results unlike it was reported for cemented femoral components of similar alloy but different design and cementation philosophy.

Alloys↗

PubMedDate not supplied

[10 years results with a Monobloc hip endoprosthesis cup with multilayer titanium mesh coating for cement-free implantation].

PURPOSE: Can a cementless hemispheric acetabular component which is made of ultra-high-density polyethylene (UHMW-PE) and a heat-bounded porous titanium mesh coating be recommended 10 years after implantation? METHODS: Between 1986 and 1988, 279 total hip arthroplasties in which the cementless socket had been used were performed in 261 patients. The results of 145 patients with 159 hip sockets (55.5%) were reviewed clinically and radiologically for comparison after a minimum of 10 years. The clinical and radiological re-examination was documented in a standardized questionnaire in which several scores were integrated. All X-rays were stored and analysed by a special hardware and software computer system. RESULTS: The mean age of the female patients (n = 85) was 63.1 years and of the male patients (n = 60) 60.9 years. The mean follow-up period was 10 years and 3 months. The Merle d'Aubigné hip score increased from 10.9 to 16.5 points at the follow-up evaluation. Radiolucent lines and cysts according to the zones of DeLee/Charnley were seen only in 2% of all cases. The mean polyethylene wear (head disarrangement) was measured with 1.79 mm after 10 years and 1.92 mm after 11 years. In total, 16 revisions (5.7%), 13 (4.6%) aseptic and 3 (1.1%) septic, out of 279 implanted sokets had to be performed. In particular, the acetabular cup with a diameter of 48 mm demonstrated a high loosening rate (4 of 9). The 10-year survival analysis (Kaplan-Meler) was measured with 92.8%. CONCLUSION: Our results with a cementless socket with titanium mesh coating show insignificant radiolucent lines and an exceptional high 10-year survivorship in which the particular implant philosophy is of great importance for the long-term success. In conclusion, the acetabular component can be recommended for further implantation.

Acetabulum↗

PubMedDate not supplied

[Cytokine profile of a human bone marrow cell culture on exposure to titanium-aluminium-vanadium particles].

INTRODUCTION: The purpose of this study was to prove the effect of wear particles, especially Tivanium, in the mechanism of the aseptic loosening of total joint prostheses. MATERIALS AND METHODS: Therefore, human bone marrow cell cultures were incubated with titanium-aluminium-vanadium particles of different concentrations which were added after the seventh day of culture (10(9), 10(8), 10(7), 10(6) particles per ml medium). From this time starts the real culture period (2 weeks). During these two weeks the medium was changed and the supernatants were sampled. Using an ELISA the cytokine levels of interleukin-6, interleukin-1beta, TNF-alpha and LDH were measured approximately every second day (1, 3, 6, 8, 10, 14). As a marker for toxicity the activity of LDH was determined. RESULTS: Incubation of a human bone marrow cell culture with titanium-aluminium-vanadium particles led to a maximum release of interleukin-6, interleukin-1beta, and TNF-alpha at high particle concentration (10(9) particles per ml medium). An increase of interleukin-1beta was only detectable at particle concentrations of 10(9) per ml medium. Exposure of the human bone marrow cell culture to titanium-aluminium-vanadium particles was toxic for high particle concentrations (10(9) particles per ml medium), as reflected by release of the intracellular enzyme LDH. DISCUSSION: This study shows the ability of tivanium wear particles in a human bone marrow cell culture to induce a signfically higher release of proinflammatory and osteolytic mediators which are responsible for the aseptic loosening of prosthesis and the problem of revisions. In comparison to other cell studies, our results were explained by the human bone marrow cell culture. The human bone marrow is the real effector tissue source "in situ" because the prosthesis is localised intramedullarly.

Adult↗

PubMedDate not supplied

[DRG based development of revenues in orthopaedic surgery. A comparison on the development of cost weights and average lengths of hospital stay in Germany (G-DRG V1.0) and in Australian teaching hospitals (AR-DRG 4.1)].

STUDY GOAL: In September 2002 the Federal Ministry of Health (BMG) has passed a decree in respect to the diagnosis related group system (G-DRG) for German hospitals (KFPV). From 2003 on the basis of this decree German hospitals were offered for the first time to use the G-DRG system optionally according to the " Section 17b Abs.4 of the Hospital Financing Law (Krankenhausfinanzierungsgesetz-KHG)". In addition the preliminary calculation data for the German DRG-System were published. The goal of this study was to compare the development of the cost weights and the average lengths of hospital stay in Australian teaching hospitals between 1998 and 2001 with the cost weights and average lengths of hospital stay in German hospitals according to the data published in the first German calculation (G-DRG V1.0). METHODS: An analysis was performed using the publically accessible reports on the national hospital cost data collections from 1998 until 2001 as they were published by the Commonwealth Department of Health and Aged Care in Australia. These data were compared with the cost weight calculation and average lengths of hospital stay calculation of the Institute for the Assessment of Cost Weights (InEK GmbH) published in the G-DRG V1.0 version. RESULTS: From 1998 until 2001 the cost weights of medical procedures such as spine fusion operations and joint arthroplasty revision operations on the hip and on the knee with severe complications and co-morbidities increased continuously. This development was not seen in DRG's without complications and co-morbidities, in food and ankle procedures and in shoulder procedures. The average length of hospital stay decreased continuously with very few exceptions. The average length of stay for so called C-DRG's (I09, I12, I13, I68, I69, I71, I75, I76) and in particular so called Z-DRG's (I16-I27) are in general longer by a factor of at least 2 in German hospitals when compared to Australian hospitals. CONCLUSION: A high quality of right-coding of ICD and ICPM Codes is a prerequisite to reach the correct revenue-relevant DRG. In Germany the average length of hospital stay is significantly longer than in Australia. In general the MDC-8-DRG's have demonstrated a smaller range when compared with the first calculated German DRG's in respect to the complexity of the procedures. Future management of the expected reductions in hospital stay will be based on a continuous co-operative efforts to improve the structural-, process- and (clinical guidelines and clinical pathways) and outcome quality of our medical procedures. The central objective of this effort is the well-being of our patients.

Arthroplasty, Replacement↗

PubMedDate not supplied

[Bone adaptation changes mechanical stress in the femur--a prospective two years follow up after Hüft-TEP implantation].

AIM: Periprosthetic adaptive bone remodeling after total hip arthroplasty (THA) has been frequently simulated in computer models, combining bone remodeling theory with finite element analysis. Unfortunately, there is still a lack of clinical validation data. The collection of prospective volumetric bone density data with a clinical computerized tomography study after THA was previously conducted. The objective of the study presented here is an additional evaluation of femoral strain. METHOD: In a prospective clinical trial with 7 female patients after THA computerized tomography (CT) and finite element (FE) modeling was patient specifically combined immediately after surgery, as well as at three and 24 months postoperatively. Mechanical strain was expressed by strain energy density. RESULTS: Corresponding to a bone density decrease, a decrease of the femoral strain energy density was observed during the two year follow-up after surgery (approximately 20 %). The predominant change occurred within the first three months and was found to be distally stronger than proximally. CONCLUSION: As far as we are aware, this is the first combination of fully prospective 3D CT density data in vivo with patient-specific finite element modeling. The assessment of mechanical strain data during a follow-up trial should be a new approach for analyzing hip stems in clinical biomechanics. A future confirmative study based on a statistical case number calculation would increase the evidence of the results presented here.

Absorptiometry, Photon↗

PubMedDate not supplied

[Design and first clinical results with the ZMR taper revision prosthesis].

AIM: The purpose of this study was to survey and to evaluate the first clinical and radiological results with the cementless ZMR taper hip prosthesis. METHOD: The modular distal-tapered stem was designed with a roughened titanium surface and sharp splines to achieve secure distal fixation and rotational stability. 90 ZMR taper hip prostheses were implanted between October 1999 and July 2002. Out of these, 4 interventions were primary and 86 were revision procedures. In 43 cases a complete hip prosthesis revision and in 43 cases a stem revision was necessary. The mean age of the 90 patients (42 males, 48 females) was 67.1 years. The mean follow-up period was 7.6 months (3 to 25 months). RESULTS: The stem displayed an excellent distal fixation. The mean subsidence could be measured with 4.3 mm. Furthermore, most cases showed a particularly favourable remodelling of the proximal femoral bone stock. Complications associated with revision included intraoperatively 4 femur fractures, 3 femur fissures, 5 femur perforations, 2 trochanter fractures and postoperatively 19 dislocations, 5 superficial wound infections, 2 transient palsies, 1 pulmonary embolism, 1 stem rotation and 4 wound healing failures. Considering these complications 15 re-revisions were necessary and the ZMR taper hip prosthesis had to be exchanged in 3 cases. CONCLUSION: On the one hand the ZMR taper hip prosthesis proved its value, particularly with regard to the stem modularity, the excellent distal fixation in conjunction with the possibility of partial body weight bearing and the rapid bone remodelling of the femur. On the other hand an increased number of postoperative complications and re-revisions occurred. Further long-term studies seem to be essential.

Aged↗

PubMedDate not supplied

[Human bone marrow cell culture--a sensitive method for the evaluation of the biocompatibility of materials used in orthopedics].

The objective of the study was to develop a test system to determine the cytotoxicity and biocompatibility of different biomaterials used in orthopedic surgery. This system was based on the use of a human bone marrow cell culture and the purpose was to find a screening method as a alternative to early animal experimental methods. The established human bone marrow cell culture has certain advantages when compared with other cell culture models. The result demonstrated a high conformity with animal experimental results.

Biocompatible Materials↗

PubMedDate not supplied

[A new plate for dorsal occipito-cervical fusion. Design, surgical technique, initial clinical results].

A survey of actually practiced methods for cranio-cervical fusion is presented, followed by the description of a new osteosynthesis-plate to solidly fuse this region. The new plate offers a number of advantages when compared with competing procedures. It is rigidly fixed to the occipital bone by five screws, sublaminar wireloops bond the vertebrae to be fused to both branches of the U-shaped plate where the individual loops are positioned into obliquely ascending slots. This safely prevents migration and disengagement resulting in a high initial horizontal and vertical stability allowing for a postoperative care without external support. During the procedure tightening of the wire loops may succeed on reposition of the deformity. The plate exists in two lengths allowing fusion of C0-C2 or more segments of the cervical spine. The typical indication is instability of C0-C2 in rheumatoid arthritis or tumoral lesions of the area. Clinical experience in 7 patients suffering from rheumatoid arthritis (follow-up: 6-31 months) is very positive, fusion has occurred in all cases.

Aged↗