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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Surgical technical treatment of the acetabulum in hip joint replacement. Evaluation of an acetabulum-preserving surgical technic based on a 10-year follow-up study].

The results of a 10-year follow-up examination of acetabular components in hip joint replacement following a protective acetabulum operating technique are demonstrated. With the exception of 4 cases in which during the operation the integrity of the acetabulum was not sufficiently observed, 90 per cent of the acetabular implants were on hand from x-rays fully integrated. A remarkable bone cement demarcation was to be found only in 10 per cent but there were no signs of loosening. The authors emphasize a protective acetabulum operating technique with special care to avoid the weakening of carrying structures of the acetabulum.

Acetabulum↗
PubMed1999

[Primary stability of press-fit acetabulum cups using a new acetabulum reamer].

The aim of the present study was to assess the initial stability of uncemented press-fit acetabular components using a newly developed reamer designed to optimize the surgical preparation of the acetabulum. Ten synthetic human pelves were used to investigate the stability of 20 uncemented press-fit acetabular components, each of which was tested in a servohydraulic testing machine for 6 cycles under an axial load of 2.4 kN. The results of the micrometric measurements revealed satisfactory stability for a reaming depth of 2 mm, and a press-fit of 2 mm. Micromotion was less than 200 microns in all the anatomical sections of the acetabulum (ischium 63 microns, pubis 150 microns, ilium 85 microns). A press-fit of 4 mm and the smaller reaming depth of 1 mm were associated with a substantial decrease in mechanical stability.

Acetabulum↗
PubMedDate not supplied

[Cement-free revision arthroplasty of the acetabulum--intermediate term outcome with trabecular-oriented acetabulum implant].

PURPOSE: In the case of hip revision arthroplasty, cementless implants combined with bone grafts are increasingly used to reconstruct the acetabular bone stock. The study on hand reports about the results with the trabecular orientated cup implant of CopflHolz after 10 years of application. METHOD: A total of 256 hip revision arthroplasties were prospectively recorded with a mean follow-up period of 5.6 years. For the osseous augmentation of the acetabulum, autogenous bone was used in 227 cases, allogenic spongy bone in 15 cases and mixed bony materials in 8 cases. The clinical and radiological follow-ups were done after 3, 6, 12 months and then in 2-years intervals. RESULTS: Within the 10 years follow-up 3 rerevisions must be done because of deep infection, 6 rerevisions because of aseptic loosening or primary instable fixation. The specific failure rate of the used cup implant amounts to 96.2% five years after revision arthroplasty, and 86.8% ten years after revision arthroplasty. Revealed from a radiological point of view, the transplanted spongiosa showed in 83.5% a complete osseous integration one year after the operation. Worse incorporation was conspicuous especially when allografts or mixed bone grafts were used. Clinically, a permanent improvement of motion, pain and walking ability was seen postoperatively. 91% of all follow-up patients were satisfied with the result of the revision arthroplasty. CONCLUSIONS: The trabecular orientated cup implant has proven itself worthy for cementless cup revision arthroplasty and will be an alternative to the cups and rings used up to now for the reconstruction of great acetabular bone deficiencies.

Acetabulum↗
PubMed1979

[Therapeutic difficulties encountered in the treatment of fractures of the acetabulum. Retrospective study of 44 cases of osteosynthesis of the acetabulum].

A retrospective study shows several factors that influence the ultimate prognosis of fracture-dislocations of the hip. The magnitude of the initial injury worsens the prognosis as far as functional recovery and residual pain are concerned. The most difficult cases are those with anterior and posterior fractures of the acetabulum. The quality of reduction is often imperfect and the techniques of surgical repair are very difficult and time consuming. Provided there is no associated lesion of the sciatic nerve, the more simple fracture (transverse and posterior) gives better operation results. Reduction is often entirely successful if the surgical technique is adequate. Despite proper treatment, some patients develop aseptic necrosis of the femoral head and are left with most severe sequela.

Acetabulum↗
PubMedDate not supplied

[The Balgrist acetabulum with uncemented endoprosthesis of dysplastic coxarthrosis and other acetabulum defects].

The Balgrist socket, one of the first cementless and non-threaded press-fit acetabular replacements, ensures primary stable fixation. Tapered design and self-locking fixation of the Balgrist socket achieve initial stability not only in osteoarthritis secondary to congenital subluxation but also in acetabular bone stock damage due to other etiologies. The non-threaded design of the socket permits easier femoral head bone grafting for reconstruction of the acetabular rim.

Acetabulum↗
PubMedDate not supplied

[Primary stability of 2 acetabulum roof cups and an acetabulum reinforcement cup. Effect of osseous defects].

The aim of this experimental study was to analyse the effects of implant design and bone stock defects on the primary stability of three different acetabular components. Fresh frozen human pelves were employed for the investigation. Müller and Ganz rings and a Burch-Schneider cage (Protek, Münsingen, Switzerland) were fixed with screws in 6 normal acetabula using standard techniques, and in 30 acetabula previously prepared with 5 different segmental bone stock defects. A servohydraulic testing machine (Instron, Canton, USA) was used for the investigation. Three electromagnetic displacement transducers (Micro-Epsilon, Ortenburg, Germany) were placed in the three main quadrants of the acetabular rim to detect implant micromotion, which reflects stability. Displacement was recorded during 20 consecutive cycles under loads of up to 2354 N. All implants were stable (< 150 microns) in all quadrants of normal acetabula and also in those with ectatic, protrusive and ventral defects. There was no statistically significant difference in the results between Müller and Ganz rings. Displacement of more than 150 microns was observed in acetabula with cranial or dorsal defects. The cage was stable under all defect conditions. The reinforcement implants showed low displacement rates in most of the acetabular bony defects. Stability is a function of the area of surface contact between prosthesis and bone.

Acetabulum↗
PubMed1985

[Preparation of the acetabulum to correct severe acetabular deficiency for total hip replacement--with special reference to stress distribution of the periacetabular region after operation].

The author analysed the radiological results of eighty-three total hip replacements in the patients with severely defective acetabulum secondary to congenital hip dysplasias or failed total hip replacements, after an average follow-up period of three years, paying particular attention to socket loosening. The patients with congenital hip dysplasias were divided into the following four groups: Group 1: The sockets were placed above the level of true acetabulum. Group 2: The sockets were placed in the true acetabulum with the cement used as a filler superolaterally. Group 3: The sockets were placed in the true acetabulum with bone grafts. Group 4: Eccentric sockets were placed in the true acetabulum. The incidence of radiological loosening of the socket was 50% in the group 1, 13% in the group 2, 6% in the group 3 and 75% in the group 4. The patients who underwent revision for socket loosening were also divided into two groups, the one whose acetabula were reconstructed with bone grafts and the other without bone graft. The incidence of radiological loosening of the socket was 28% in the group with bone grafts and 72% in the group without bone graft. The major factor that may have been responsible for socket loosening in these cases was considered to be poor mechanical condition around the socket due to bone deficiency. Two-dimensional finite element analysis was performed to establish the stresses in the periacetabular region after total hip replacement for acetabular deficiency. Model variations include, the conventional plastic socket of 44 mm outside, 28 mm inside diameter placed in false acetabulum or in high level, (2) in true acetabulum using bone cement as a filler, (3) in true acetabulum with bone graft and (4) eccentric socket placed in true acetabulum without bone graft. The ratio of von Mises stress to yield stress of each element were calculated. The results demonstrated that in the periacetabular region, the area superomedial to the socket was at high risk in each model. The area in periacetabular bone where the ratio of von Mises stress to yield stress was more than 20% was almost the same in model (1), (2), (4) and about a half of them in model (3). In conclusion, the most effective method to prevent the socket loosening after total hip replacement in the patient with deficient acetabulum was considered to reconstruct the new spherical acetabulum at anatomical position with bone graft.

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PubMed1999

Can an enlarged acetabulum cover the femoral head well in Legg-Calvé-Perthes disease?

Changes in the acetabulum play an important role in the final results of Legg-Calvé-Perthes disease (LCPD). To determine the relationship between the acetabulum and the final results, the acetabulum was measured in 108 children with unilateral LCPD. The acetabular radius, depth, width; iliac width and height; and medial joint distance were measured on the radiographs initially and on follow-up. The parameters between the affected and the unaffected sides were compared by using t test. Herring's classification was employed to evaluate the extent of involved femoral head. The results showed that the radius of the acetabulum was the most sensitive measurement representing the pathologic changes in the acetabulum. The acetabular hypertrophy occurred very early in the avascular necrosis stage. It resulted in the lateral subluxation of the femoral head and in loss of containment. During the later stage of the disease, the femoral head overgrew and broke the growth limit of the acetabulum. Coxa magna made it difficult for a hypertrophic acetabulum to contain it.

Acetabulum↗
PubMed1999

The effects of simulated transverse, anterior column, and posterior column fractures of the acetabulum on the stability of the hip joint.

BACKGROUND: Knowledge of the location of the weight-bearing portion of the acetabulum would assist orthopaedic surgeons in the treatment of acetabular fractures. With use of controlled experimental transverse, anterior column, and posterior column osteotomies, we investigated the weight-bearing region of the acetabulum. METHODS: Twenty-four fresh-frozen cadaveric hip joints were tested. Simulated transverse fractures were evaluated in twelve specimens, and simulated anterior column and posterior column fractures were tested in six specimens each. Each femur and acetabulum was potted and mounted in an aluminum fixture, with the acetabulum positioned in 25 degrees of flexion and 20 degrees of abduction. Each specimen was tested intact and after successive osteotomies. The transverse osteotomies had roof-arc angles of 60, 50, 40, and 30 degrees. The anterior column and posterior column osteotomies were classified as very low, low, intermediate, or high. Compressive loading to 800, 1200, and 1600 newtons was performed four times for each intact specimen and after each osteotomy. A specimen was considered to be stable if no gross dislocation occurred during any of the four loading cycles. Translation of the femur within the acetabulum also was measured during each trial. RESULTS: The number of stable specimens decreased both with higher applied loads and with more superior osteotomies. The stability of the hip was significantly affected by both the location of the fracture and the magnitude of the applied load (p < 0.00005). Translation of the femur within the acetabulum increased with higher applied loads and with more superior osteotomies. CONCLUSIONS: Fractures that have a medial roof-arc angle of 45 degrees or less, an anterior roof-arc angle of 25 degrees or less, or a posterior roof-arc angle of 70 degrees or less cross the weight-bearing portion of the acetabulum and necessitate operative treatment.

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PubMed2003

Radiological remodelling of the acetabulum in Perthes' disease.

Thirty-four patients were studied throughout the evolution of Perthes' disease. The acetabular changes included osteopoenia of the roof, irregularity of its contour, and decrease in its depth. These changes were proportional to the femoral head involvement. The purpose of the study was to assess the effect of the morphological changes of the femoral head on the acetabulum and the outcome, and to determine the extent to which coxa magna and acetabular enlargement induced by Perthes disease in childhood persist into adolescence. Radioisotope scans of the hip were examined in fourteen children with unilateral Perthes' disease and comparison was made with the contralateral hip. These scans showed increased uptake on the lateral part of the acetabulum and no uptake over the avascular part of the femoral head. Average follow-up was ten years and children were followed up on average from six years to fifteen years of age. Six readings of the measurements of various dimensions of the acetabulum and the femoral head were done. CT scan also showed irregularity in the acetabulum. Statistical tests lead to the conclusion that the decrease in the depth of the acetabulum was secondary to the femoral head involvement and the extent of its dimensional changes affected the final congruity between the femoral head and the acetabulum. Also the remodelling potential of the acetabulum decreases as the child grows older. Therefore containment procedures could be done by femoral osteotomy in younger children, whereas acetabular osteotomy may benefit older children.

Acetabulum↗
PubMed2003

[Morphologic features of the acetabulum bone joint area].

The research on the morphology features of the acetabulum bone joint surface area would be helpful to establishing the acetabulum 3D model for the purpose of the biomechanical analysis of hip joint, and therefore might have its important clinical significance. However, in former studies, the acetabulum was simply considered as a semi sphere. In this study, based on the acetabulum 3D-point data acquired by the 3D laser surface scanner and the reverse engineering technology together with the optimal fit algorithm, two kinds of best-fit model were achieved by a sphere surface and a rotating elliptical surface respectively approaching to the acetabulum bone joint surface. Both fitting errors were then compared and analyzed. The results showed that the fitting error of the rotating elliptical surface was significantly less than that of the sphere surface (P < 0.001). The average radius of fitting sphere was 24.37 +/- 2.22 mm and the average long axis of fitting rotating elliptical surface was 26.02 +/- 2.76 mm while its short axis was 24.17 +/- 2.16 mm. These findings would be helpful to our new recognition of the acetabulum since they were results of the first quantitative analyses for the acetabulum bone surface and also might serve as an important reference base in its further studies and application.

Acetabulum↗
PubMed1992

Danger zone of the acetabulum.

The danger zone of the acetabulum is defined by Marvin Tile as that part of the posterior wall and column at the mid-acetabulum lying above the ischial spine. Screws inserted in the danger zone are at risk of violating the hip joint. Unfortunately, this zone is frequently used in the fixation of posterior wall and column fractures. Cadaveric studies were performed analyzing 1-cm cross-sections through the acetabulum for the purpose of studying the anatomical configuration of the danger zone. The plane of the cross-section was perpendicular to the posterior column. Each cross-section had the medial boundary of the acetabulum projected onto the posterior column. The cross-sections were then assembled to form the original acetabulum. By analyzing the projections on the posterior column, the exact configuration of the danger zone was determined. Screws placed at the margin of the danger zone and directed perpendicular to the posterior column violated the hip joint. Through analysis of the cross-sections, safe anatomic pathways were developed for screw placement. Cortical screws (4.5 mm), placed at entry points of 2 cm and 3 cm medial to the lateral acetabular margin and angled medially 45 degrees and 15 degrees, respectively, did not violate the hip joint. The angulation was respective to the perpendicular to the posterior column. In this study, the average width of the posterior column at the mid-acetabular level was 4.8 cm. Computed tomography scan of the acetabulum yielded valuable information regarding screw placement in the posterior column.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetabulum↗
PubMed1982

Anteversion of the acetabulum in patients with idiopathic increased anteversion of the femoral neck.

Examination of the hip joint by computed tomography was evaluated in 34 children admitted to hospital with symptoms of idiopathic increased anteversion of the femoral neck and in 6 children with congenital dislocation of the hip. Anteversion of the femoral neck and the acetabulum was determined from tomographic cross-sections, and femoral anteversion was also determined by conventional radiography. A good correlation was found between these two methods. The relationship between anteversion of the femoral neck and that of the acetabulum was calculated in the 34 patients with idiopathic increased femoral anteversion. In creased anteversion of the femoral neck was not compensated for by a corresponding reduction in the ventral orientation of the acetabulum. In many cases the adjustment of the acetabulum to the femoral head was poor. In some of the patients the degree of external rotation of the hip was greater than would be expected from the relationship between the anteversion of the femoral neck and that of the acetabulum. In these patients the lower limb is forced outwards when walking, causing the femoral head to dislocate laterally and forwards. Based on the results of this study we conclude that calculation of the anteversion, both of the femoral neck and acetabulum, should play an important part in the evaluation of candidates for derotational osteotomy of the femur. Computed tomography yields valuable information in this respect.

Acetabulum↗
PubMed2005

[Computerized three-dimensional reconstruction and morphologic measurement of adult acetabulum bone structure].

OBJECTIVE: To set up three-dimensional reconstruction of acetabulum bone structure from CT scanned image in computer with software of CAD and study quantitatively the morphologic features of the acetabulum. METHODS: Through the process of CT scanning, and edge recording of the CT image, we made use of CAD software and Unigraphics software to reconstruct the 40 normal acetabulum bones for the radius of acetabulum (R), minimum thickness of medial wall of acetabulum (L), depth of Harris fossa (D) and maximum opening rim width in cross-sectional plane (W). RESULTS: The average R was 30.48 +/- 2.05 mm. The average L was 2.35 +/- 1.13 mm. The average D was 5.71 +/- 1.21 mm. The average W was 63.06 +/- 2.05 mm. There was a linear relationship between the R and the W, but no correlation between the R, the L and the D. CONCLUSIONS: There was a significance linear relationship between the R and the W in normal adult acetabulum. However no correlation between the R, the L and the D.

Acetabulum↗
PubMed1986

[Growth disturbance of the acetabulum by damage to the triradiate cartilage of rabbits].

We made the following two experiments to know how the disturbed triradiate cartilage influences the growth of the innominate bone, particularly that of the acetabulum. Experiment 1: Damage to the anterior and posterior flanges of the triradiate cartilage. Experiment 2: Damage to the structures adjacent to the triradiate cartilage by drilling. As a result of these experiments, in Experiment 1 acetabular dysplasia and thickening of the inner wall of the acetabulum as reported in the past were seen and thickening of the outer cortex of the acetabular edge, irregular arrangement, decreases in number of hypertropic cells in growth plate, diminishing of bone formation, irregular hypertrophies of the trabecula were also noted in the whole acetabulum histologically. In Experiment 2, only the thickening of the inner wall of the acetabulum was seen. As described above the anterior and posterior flanges of the triradiate cartilage participate in acetabular growth and damaging makes the acetabulum small in size. While the femoral head grows normally, incongruity between the two occurs, so dislocation of the femoral head, acetabular dysplasia and thickening of the inner wall of the acetabulum are secondarily produced by the damage of articular cartilage or growth plate.

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