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Analysis of retrieved hip joint was presented. Bone remodeling considering the distribution of friction products was discussed. Scanning electron microscopy methods were used to perform on structural analysis. We expressed a surface changing prosthetic head as Ra (roughness average). X-Ray Microanalysis was applied to study products of degradation.
Authors report on their material of total hip endoprosthesis, performed 30 May 1969--31 August 1988 on the Department of Orthopaedics of the Semmelweis University of Medical Science. In this period 1480 operations were made. The formerly and recently used operative technique and the types of the prostheses are described. The intraoperative, the early and the late complications and their treatment are also described. The formerly and recently used tactics of reoperation is reported and attention is called to the fact that the success rate of the replantation can be increased by an adequate technical skill.
We have followed up 227 total hip replacements using a cementless minimadreporic prosthesis for an average of 9 1/2 years. Special attention was paid to the acetabular component, of which 2 types were used; 77 incorporated screw rings and 134 were stabilised by spikes. The screw prostheses were evaluated at an average of 8 1/2 years from operation; one third showed radiological evidence of migration, and revision because of this was required in 12.6% of cases. The spiked cups were followed up for an average of 10 years; 14.8% showed radiological evidence of migration and 2.3% needed revision. We observed no radiological features to explain this difference. The quality of the bone and the mechanical characteristics of the bone/implant contrast may influence the result. We feel that an uncemented spiked acetabular implants is a worthwhile concept.
Our physiotherapy program after total hip arthroplasty is presented, and certain modifications in relation to cemented or cementless implantations are discussed. Three different stages must be considered: preoperative instructions of the patient, mobilization of the patient and his joints, water gymnastics to enable the patient to obtain total independence. During the first three months only partial weight should be put on the operated leg. In comparison to the cemented system, the biomechanical properties of the cementless prosthesis permit only a careful and delayed mobilization and charge of the operated leg, as long as a secondary stability of the implant has not been reached. In more complicated cases it is of importance that the whole planning of postoperative physiotherapy should be discussed individually and in detail with the surgeon concerned.
The natural stress distribution in the femur is significantly altered after total hip arthroplasty (THA). When an implant is introduced, it will carry a portion of the load, causing a reduction of stress in some regions of the remaining bone. This phenomenon is commonly known as stress shielding. In response to the changed mechanical environment the shielded bone will remodel according to Wolff's law, resulting in a loss of bone mass through the biological process called resorption. Resorption can, in turn, cause or contribute to loosening of the prosthesis. The problem is particularly common among younger THA recipients. This study explores the hypothesis that through redesign, a total hip prosthesis can be developed to substantially reduce stress shielding. First, we describe the development of a new femoral hip prosthesis designed to alleviate this problem through a new geometry and system of proximal fixation. A numerical comparison with a conventional intramedullary prosthesis as well as another proximally fixed prosthesis, recently developed by Munting and Verhelpen (1995. Journal of Biomechanics 28(8), 949-961) is presented. The results show that the new design produces a more physiological stress state in the proximal femur.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Between January 1987 and December 1990, 221 Zweymüller cementless total hip arthroplasties were performed in 211 patients with idiopathic osteoarthritis. A total of 136 patients (142 prostheses) were evaluated at a mean follow-up of 134 months (SD 9.5). The study group consisted of 78 Hochgezogen and 64 Stepless stem prostheses, all with a threaded titanium cup and ceramic head. No clinical and radiological differences were found between the 2 stem prostheses. Seven cups had been revised because of aseptic loosening; 17 cups showed radiolucent lines, osteolysis, or migration. Mean linear polyethylene wear of 105 (74%) cups was 0.46 mm (SD 0.27), with an annual wear of 0.04 mm (SD 0.02). Wear did not correlate with pain, cup migration, radiolucent lines, or osteolysis. Cumulative survival was 96%. Zweymüller cementless total hip arthroplasty showed good midterm results.
Thirteen patients were analyzed who suffered from chronic infection after total hip replacement. Some of them had had severe soft tissue defects or multiple fistulae for years. Some showed acute, sometimes life-threatening infection after long-standing loosening of the prosthesis. Therapy consisted of radical debridement, installation of a closed suction-irrigation drainage system and if another total hip prosthesis was implanted of a specific antibiotic management, including rifampin. In one case treatment was limited to the achievement of a permanent fistula. The average follow-up time was 4.3 years. With or without total hip reimplantation infections were healed as a rule and the decrease in pain was marked. There was only a partial increase in walking ability. In these severely damaged patients treatment can result in marked amelioration of the quality of life but only exceptionally in normalization.
In elderly patients bipolar hip prostheses are often used for intracapsular fractures of the femoral neck and are often complicated by pain after a few years; this pain is frequently related to acetabular erosion seen on xray. In this study 18 bipolar hip prostheses were used in the treatment of a proximal femoral sarcoma in a young patient population (mean age: 39.6 years). Their quality of life was evaluated by TESS and MSTS scores, after a mean follow-up of 81.8 months (range 8-171 months). A radiologic grading system was used to assess acetabular erosion on plain xrays. The patients did not report significant pain, they enjoyed a very good quality of life, and they did not show any obvious acetabular erosion. The use of a bipolar implant appears as a good alternative to total hip replacement in the treatment of relatively young patients who have to undergo proximal femoral tumor resection procedures and have a normal acetabulum.
PURPOSE OF THE STUDY: The authors report an original case of Albers-Schönberg's disease and describe its surgical treatment. MATERIAL: Comparison between roentgenogram of the pelvis at the age of 9 and 46 years showed the original evolution of coxa vara in a case of osteopetrosis. A 46 year old male had severe pain and instability in both hips related to numerous problems consisting of: 1) on the right side: subtrochanteric femoral non-union after repeated fractures, head and neck femoral disappearance associated to dislocation. 2) on the left side: acetabular dysplasia, osteoarthritis and subtrochanteric femoral fracture that had fusionned. Total hip arthroplasty was performed on both hips. RESULT: Clinical result was good in both hips (PMA score = 6-6-4) at the latest follow-up (four years on the left side and three years and four months on the right side). The surgical procedures were difficult because of the hardness and brittle character of the bony substance and because of non unions and deformities. Special care was required to avoid shattering femoral diaphysis and false routes during creation of a new medullary canal. CONCLUSION: Total hip prosthesis represents a functionnal salvage procedure in patients with Albers-Schönberg's disease.
The introduction of a proximally modular hip stem has greatly simplified difficult hip surgery. The long-term results of revision surgery indicate that the majority of revision cases can be handled with a proximal ingrowth implant, which helps speed bone recovery and simplifies re-revision if it is required. To date no particular downside has been noted as a result of the use of a modular stem.
The Zweymüller shaft for uncemented total hip arthroplasty was developed in the early 1970s. Encouraged by the clinical results with this stem, which was mainly used in primary arthroplasty, longer fitting stems were added to the line to accommodate bony defects and to allow for an optimal load transfer from proximal to distal. The principal of the design is to allow an optimal distal fixation while allowing the bone to remodel in the proximal part. This study reports on 89 patients who underwent revision surgery of the hip for mostly aseptic loosening. The results after a median follow-up of 36 months show an increase of the modified Harris hip score from 52 points pre- to 82 points postoperatively. Radiographic subsidence was found in nine cases, with eight having progressed for more then 3 mm. Postoperative complications occurred in 11.2%, with seven dislocations. Open revision became necessary in two cases. The stem reviewed here seems to achieve predictable results in cases where a proximal cone is still present to facilitate load transfer, while at the same time the quadrangular stem provides solid distal fixation and ensures rotary stability.
The wear was examined in 39 Christiansen total hip prostheses, which were removed because of mechanical loosening after being used 5 (3-11) years. In the polyacetal acetabular cups, the head had made an eccentric defect, the mean volume of which was 680 (180-3310) mm3. The mean penetration of the head into the wall of the cup was 0.8 (0.1-3.2) mm. In two additional cups the head had penetrated right through the wall of the cup. In three prostheses the polyacetal sleeve of the trunnion was so worn that the head bore directly on the stem. There was a positive correlation between wear and the time the prostheses had been used before symptoms of loosening presented.