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PubMed2004

[Implantation of a non-cemented acetabulum with the use of a navigation system].

PURPOSE OF THE STUDY: To compare, on the basis of clinical and radiographic findings, the results of non-cemented acetabulum implantation involving the use of a CT-free navigation system with those of implantation without its use. MATERIAL: A total of 50 patients undergoing implantation of a non-cemented acetabulum in the period from April 2002 to September 2003 were evaluated. Twenty-five patients operated on without the navigation system were included in group 1 on a random basis and 25 patients treated with the use of the system constituted group 2. METHODS: Both groups were evaluated on the basis of clinical and X-ray findings. The radiographic measurement of acetabulular inclination was based on anteroposterior projection of both hips made on films on films equal in size. Anteversion of the acetabulum was assessed according to the Ackland system. The Merle d'Aubigne and Postel scores were used for clinical evaluation. The results were compared statistically. RESULTS: In group 1, the average inclination was 50.6 degrees (range, 38-62) and the average anteversion was 9.4 degrees (range, 3-18). In group 2, the values were 43.0 degrees (32-55) and 10.4 degrees (8-16) for the average inclination and anteversion, respectively. The difference in acetabular inclination between the two groups was statistically significant. When accuracy was evaluated, the difference in acetabular anteversion was statistically significant. DISCUSSION: The achievement of an optimal position of the acetabular component is one of the important factors for good, long-term outcomes of hip replacement. The optimal position that, as suggested by many authors, involves an inclination of 45 +/- 10 degrees and an anteversion of 15 +/- 10 degrees provides sufficient stability, low wear and a satisfactory range of motion in the hip joint. The results close to these values were achieved in the patients included in group 2. CONCLUSIONS: A comparison of the groups showed that the computer-assisted navigation system used in implantation resulted in an optimal position of the acetabular component.

Acetabulum↗
PubMed2006

[An anatomic study of lag screw placement in anterior column of acetabulum and design of targeting device].

OBJECTIVE: To provide the anatomic basis for the lag screw placement in the anterior column of the acetabulum. METHODS: Twenty-two pelvis specimens with 44 acetabula of the native adult cadavers were studied. The anthropometric measurement was performed on 44 acetabula to determine the shape of the transverse section of the anterior column of the acetabulum, the optimal entry point for the lag screw on the outer table of the ilium, the direction of the screw, and the distance from the entry point to the obturator groove. RESULTS: The transverse section of the anterior column of the acetabulum was almost triangle-shaped. The path for the lag screw placement was 10.5 +/- 0.8 mm in diameter. The optimal entry point on the posterolateral ilium for the screw fixation was found to exist 9.2 +/- 2.4 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 38.5 +/- 3.8 mm superior to the greater sciatic notch. The distance from the entry point to the obturator groove was 84.1 +/- 6.2 mm. The inclination of the lag screw was 54.2 +/- 5.5 degrees at the caudal direction in the sagittal plane and 40.7 +/- 3.8 degrees in the horizontal plane. The device for the safe screw placement in the anterior column was designed. CONCLUSION: The above data can facilitate an insertion of one 6.5 mm lag screw into the anterior acetabular column and minimize the risk of articular violation or cortical penetration, which has a narrow margin of safety. The safe length of the lag screw should be 70 mm. The optimal entry point on the posterolateral ilium for the screw fixation is determined to be 10 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 40 mm superior to the greater sciatic notch. The inclination of the lag screw should be 55 degrees at the caudal direction in the sagittal plane and 40 degrees in the horizontal plane. It is safe to place the lag screw in the anterior column with the help of the targeting device.

Acetabulum↗
PubMed1990

The relationship of the intrapelvic vasculature to the acetabulum. Implications in screw-fixation acetabular components.

The use of screw-fixation acetabular components in total hip arthroplasty could increase the incidence of vascular injury because of the increased use of drills and screws placed into the acetabulum in close proximity to major vessels. Analysis of two illustrative case studies, anatomic specimen cross sections, and computed tomographic scans demonstrate which vessels are at risk of injury should the inner cortex of the pelvis be penetrated. The iliac vessels are at risk of injury when penetration of the inner cortex of the pelvis occurs in the anterosuperior region of the acetabulum. The obturator vessels are at risk when penetration occurs in the anteroinferior quadrant of the acetabulum. The vessels can be within 0.5 cm of the inner cortex of the pelvis and tend to become closer with advancing age. Damage to the intrapelvic vessels may cause profound blood loss and hypotension when screw-fixation acetabular components are used. Rapid identification and immediate surgical repair of vessel lacerations are essential in the treatment of this complication.

Acetabulum↗
PubMed1987

Image analysis of trabecular structure of the acetabulum in cadavers.

Trabecular structure of the acetabulum was studied in adult cadavers by means of image analysis. Two groups of trabecular patterns were distinguished in terms of orientation with reference to the frontal plane: one group runs concentric to the articular surface of the acetabulum, and the other rises perpendicular from it and runs radially. The density of the trabeculae tends to decrease with age, and density differences with age are more marked in non-weight-bearing than in weight-bearing regions. Older females, in comparison with males of the same age group, show lower trabecular density in non-weight-bearing regions. Regional differences were also noted with higher density in the anterosuperior and posteroinferior regions, decreasing centripetally from the margin of the acetabular fossa. The average density in weight-bearing regions was 6 per cent higher than that of non-weight-bearing regions. According to these findings, the trabecular pattern of the acetabulum has a structure responding to compressive and tensile stresses applied to the hip joints.

Absorptiometry, Photon↗
PubMed1986

Allograft reconstruction of the acetabulum during revision total hip arthroplasty. Clinical, radiographic, and scintigraphic assessment of the results.

In twenty-one hips of twenty-one patients, the acetabulum was reconstructed using allografts during revision of a total hip arthroplasty. The patients' average age at the time of revision was 64.3 years (range, nineteen to eighty-six years). At an average follow-up of 3.5 years (range, two to five years), three patients had died of causes unrelated to the hip reconstruction, and one had been lost to follow-up. In the other seventeen, the average Harris hip rating was 89 points (range, seventy to 100 points) at follow-up. In one patient the allograft collapsed, so that revision was required. Two patients had asymptomatic progressive radiolucencies at the cement-bone interface of the reconstructed acetabulum, and another had a 1.5-millimeter-wide lucency at the interface of the donor and recipient bone but was asymptomatic, and there had been no change in the position of the cemented acetabular component since operation. The remaining grafts appeared to be incorporated securely, as determined by radiographic examination. Three-dimensional computerized tomographic radioisotopic bone scans showed uniform uptake, consistent with revascularization and new-bone formation, in all grafts. There was no radiographic evidence of focal avascularity and there were no infections. Femoral-head bone allografts appear to provide a useful technique for the reconstruction of a severely deficient acetabulum during revision total hip arthroplasty.

Acetabulum↗
PubMed1986

[Osteoid osteoma of the base of the acetabulum presenting as coxitis in a 14-year-old girl].

It is about an unique case of an intra-articular osteoid osteoma, located in the back of the acetabulum in a 14 years old girl. Synovitis made clinical and radiological appearances very suggestive of an arthritis. Diagnosis was recalled in the view of biological negativity, the notion of nocturnal pains, reduced by aspirin, and especially radiological features with densification of the back of the acetabulum. Scintigraphy revealed hyperfixation located in the back of the acetabulum and scanner showed a picture, in the same place, buldging towards the joint, suggestive of the osteoid osteoma. The operation, made by anterior approach with anterior dislocation of the hip, allowed the "in bloc" resection of an osseus piece whose immediate radiographic examination confirmed that the whole osteoma was removed. A synovial biopsy was also performed. The pathologist confirmed the diagnosis and showed a reactional synovitis within the soft tissues. Pain disappeared as soon as the waking up. This case report is interesting because: this localization is very exceptional, the reactional synovitis was evocating of an arthritis, the iconography is absolutely complete, a review of publications is done for this subject.

Acetabulum↗
PubMed1980

[The effects of innominate ostèotomy on the opposite acetabulum (author's transl)].

The study on dissected pelvis shows that after innominate osteotomy, the acetabulum still faces too much anteriorly. Its anterior wall remains deficient. The innominate osteotomy is able to diminish the excessive antetorsion of the acetabulum by rotating the distal fragment outwards. But this movement seems to increase the antetorsion of the opposite acetabulum. Axial X. Rays of the pelvis authors think that in case of great anterior defect, and in case of bilateral hip dysplasia, a triple pelvic osteotomy will be preferred to Salter's osteotomy.

Acetabulum↗
PubMed1984

[Growth of the human acetabulum--with a comparison of cartilaginous proliferation in acetabular and triradiate physeal cartilages].

For the purpose of investigation on the human acetabular growth, proliferation of cartilage cells as well as extent and degree of maturation of newly formed trabeculae in both acetabular and triradiate physeal plates were observed. The material consisted of 13 acetabula of the left hip joints from necropsies whose age distribution ranged from the period of neonate to adolescence. The acetabulum was divided into 5 parts by radial lines. Histological sections were then prepared from each of these parts. The growth of the acetabulum was mainly based on the development of the acetabular and triradiate physeal cartilages, and it seemed that the course of newly formed trabeculae from both physeal plates showed centripetally directed arrangement, with convergence upon a point. These trabecular arrangement was most conspicuous in the neonatal period in which active new bone formation progressed. Based on these findings it would be reasonable to consider that the acetabular physeal cartilage takes a large part of increase in depth of the acetabulum, while the triradiate one is mainly responsible for increase in its diameter. From neonatal period to about 1 year of age there was an active growth of both acetabular and triradiate cartilages. With age the growth rate of physeal plates showed a decrease, and there was a tendency to a predominance of triradiate cartilage proliferation over acetabular one. On reaching adolescence cessation of cartilage growth occurred in both physeal plates.

Acetabulum↗
PubMed1984

Arthroprosthesis in old unreduced congenital dislocation of the hip, using the "false" acetabulum. A study of 34 cases.

In adult patients with considerable loss of function due to an unreduced congenital dislocation of the hip with a false acetabulum, the authors posed the question "Is it feasible, with a reasonable chance of success, to perform an arthroprosthesis in the "pathological" position, using the false acetabulum as a seating for the cup?" The aim of this study was to assess, in particular, the holding properties of the cup which has to be fitted after appropriate reaming, into this rather precarious false acetabulum. They define the indications for this procedure and describe their technique. The results of 34 operations, followed up for an average of 5 years, confirm the validity of this procedure.

Acetabulum↗
PubMed1980

Congenital dislocation of the hip. The fate of the well-developed acetabulum.

In a previous study of 177 hips treated in infancy for congenital dislocation and followed for 10 to 27 years, all were found to have well-developed acetabula. Nevertheless, there were two cases with minimal arthrotic changes. In this paper, a further study of 107 of these hips, with a follow-up of 15 to 30 years, indicates that the number of hips with arthrotic changes has increased. Attention was given to the fate of the acetabulum in relation to its depth or shallowness as measured by the CE angle. It is concluded that a hip with a slightly shallow acetabulum (CE angle, approximately 20 degrees) is less susceptible to wear or deterioration than a hip with a deeper acetabulum (CE angle, greater than 25 degrees).

Acetabulum↗
PubMed1980

Acetabulum fractures: classification and management.

Twenty-two years of experience in this field allow us to say that a perfect open reduction is the method of choice to treat displaced acetabular fractures. But difficult cases require experience. Late follow-up of hips treated by open reduction and internal fixation supports the contention that a satisfactory outcome can be expected if the fracture reduction is perfect. The converse applies, and in some instances it would have been better to accept the result which might have been obtained by conservative methods. The type of fracture dictates the choice of approach, but the indication for operative treatment as well as the result of acetabular fracture treatment is the degree of congruence achieved between the acetabulum and the femoral head. Incongruence may be total, partial or apparent. Total incongruence is seen in both persistent posterior or central dislocation in which, on all three standard radiographs, the fragments of the acetabulum are seen separated from the femoral head. The situation may exist from the moment of trauma or following attempts at reduction. In all instances, operative treatment is indicated. With partial incongruence, the femoral head lies well centered beneath an undisplaced fragment of roof, but other fragments of articular surface remain displaced. A very good clinical result cannot be expected in more than 55% of hips left in this state, and neglecting operative complications, the same can be expected following conservative management. A small degree of incongruence can be accepted but one of the difficulties lies in determining the size of the fragment "roof" left in situ. Certainly, congruency seen on one standard radiograph and not in the others must not be accepted, and surgical treatment is indicated. With apparent congruence, the fragments of shattered acetabulum have regrouped around a displaced femoral head and exhibit a fair degree of congruence in this displaced position. Examples like this can often be treated conservatively because while surgery may achieve a better true congruence, this cannot be guaranteed and will be accompanied by the risks of operation. Further, the result could be worse. In nine acetabular fractures, it has been possible to achieve an apparent congruence by reconstituting displaced acetabular fragments around the femoral head but accepting the overall displacement. Seven of these obtained very good clinical results but it should be emphasized that the need to resort to this approach has been very infrequent.

Acetabulum↗
PubMed2001

Characterization of a nicotinamide nucleotide transhydrogenase gene from the green alga Acetabularia acetabulum and comparison of its structure with those of the corresponding genes in mouse and Caenorhabditis elegans.

Proton-pumping nicotinamide nucleotide transhydrogenase (Nnt) is a membrane-bound enzyme that catalyzes the reversible reduction of NADP(+) by NADH. This reaction is linked to proton translocation across the membrane. Depending on metabolic conditions, the enzyme may be involved in NADPH generation, e.g., for detoxification of peroxides and/or free radicals and protection from ischemic damage. Nnt exists in most prokaryotes and in animal mitochondria. It is composed of 2-3 subunits in bacteria and of a single polypeptide in mitochondria. An open question is whether Nnt exists in any photosynthetic eukaryotes and if so, to which class it belongs. In the present study it is demonstrated that, by cloning and sequencing cDNA and genomic copies of its NNT gene, an ancient alga, Acetabularia acetabulum (Chlorophyta, Dasycladales), contains a nuclear-encoded Nnt. In contrast to photosynthetic bacteria, this algal Nnt is composed of a single polypeptide of the class found in animal mitochondria. Excluding a poly(A) tail, NNT cDNA from A. acetabulum is 3688 bp long, consists of eight exons and spans 17 kb. The NNT gene from mouse was also characterized. Subsequently, the gene organization of the A. acetabulum NNT was compared to those of the homologous mouse (100 kb and 21 exons) and Caenorhabditis elegans (5.1 kb and 18 exons) genes.

Amino Acid Sequence↗
PubMed1999

Aaknox1, a kn1-like homeobox gene in Acetabularia acetabulum, undergoes developmentally regulated subcellular localization.

Homeobox-containing genes play developmentally important roles in a wide variety of plants, animals and fungi. As a way of studying how development is controlled in the unicellular green macroalga Acetabularia acetabulum, we used degenerate PCR to clone a knotted1-like (kn1-like) homeobox gene, Aaknox1 (Acetabularia acetabulum kn1-like homeobox 1). Aaknorx1 is the first knotted1-like homeobox gene to be cloned from a non-vascular plant and shows strong conservation with kn1-like genes from the vascular plants (ca. 56% amino acid identity within the homeodomain). Sequencing of cDNA clones indicates that Aaknor1 possesses at least two distinct polyadenylation sites spaced ca. 600 bp apart. Southern analysis suggests that several other kn1-like homeobox genes exist in the Acetabularia genome. Northern analyses demonstrate that expression of Aaknox1 is developmentally regulated, with peak levels of expression during early reproductive phase. Northern analyses further demonstrate that Aaknox1 mRNA undergoes a change in its subcellular localization pattern during the progression from late vegetative to early reproductive phase. In late adult phase, Aaknox1 is distributed uniformly throughout the alga; in early reproductive phase, Aaknox1 is present in a gradient with the highest concentration of the mRNA at the base of the stalk, near the single nucleus. These data suggest that Aaknox1 may have a role during early reproductive development and that mRNA localization may be one mechanism by which A. acetabulum regulates gene expression posttranscriptionally.

Acetabularia↗
PubMed2001

Asymmetric subcellular mRNA distribution correlates with carbonic anhydrase activity in Acetabularia acetabulum.

The unicellular green macroalga Acetabularia acetabulum L. Silva is an excellent system for studying regional differentiation within a single cell. In late adults, physiologically mediated extracellular alkalinity varies along the long axis of the alga with extracellular pH more alkaline along the apical and middle regions of the stalk than at and near the rhizoid. Respiration also varies with greater respiration at and near the rhizoid than along the stalk. We hypothesized that the apical and middle regions of the stalk require greater carbonic anhydrase (CA) activity to facilitate inorganic carbon uptake for photosynthesis. Treatment of algae with the CA inhibitors acetazolamide and ethoxyzolamide decreased photosynthetic oxygen evolution along the stalk but not at the rhizoid, indicating that CA facilitates inorganic carbon uptake in the apical portions of the alga. To examine the distribution of enzymatic activity within the alga, individuals were dissected into apical, middle, and basal tissue pools and assayed for both total and external CA activity. CA activity was greatest in the apical portions. We cloned two CA genes (AaCA1 and AaCA2). Northern analysis demonstrated that both genes are expressed throughout much of the life cycle of A. acetabulum. AaCA1 mRNA first appears in early adults. AaCA2 mRNA appears in juveniles. The AaCA1 and AaCA2 mRNAs are distributed asymmetrically in late adults with highest levels of each in the apical portion of the alga. mRNA localization and enzyme activity patterns correlate for AaCA1 and AaCA2, indicating that mRNA localization is one mechanism underlying regional differentiation in A. acetabulum.

Acetabularia↗
PubMed1998

Transverse subgluteal-ilioinguinal approach to the acetabulum.

An approach to the acetabulum is described. This approach consists of an anterior and a posterior part. The anterior part is nearly identical with the ilioinguinal approach. The posterior part resembles Kocher's (Gibson, J Bone Joint Surg 1950;32B:183-186) original description in that the plane of dissection passes between the motor territories of the superior gluteal nerve anterolaterally and the inferior gluteal nerve posteromedially. Two modifications have been introduced, however. First, the incision is a transverse one; superior and inferior fasciocutaneous flaps are elevated. Second, the gluteus maximus is not only disinserted from the fascia lata and the gluteal tuberosity at the upper end of the femur but from the iliac crest as well. After ligating the superficial branch of the superior gluteal artery to the gluteus maximus, the muscle itself is reflected posteromedially. We have used this approach to explore the lumbosacral plexus and its branches, particularly the sciatic nerve at the greater sciatic notch. Due to the excellent exposure of both columns of the acetabulm, this approach may be equally used in fractures of the acetabulum.

Acetabulum↗
PubMed2007

Corona mortis: an anatomical study with clinical implications in approaches to the pelvis and acetabulum.

The "corona mortis" is an anatomical variant, an anastomosis between the obturator and the external iliac or inferior epigastric arteries or veins. It is located behind the superior pubic ramus at a variable distance from the symphysis pubis (range 40-96 mm). The name "corona mortis" or crown of death testifies to the importance of this feature, as significant hemorrhage may occur if accidentally cut and it is difficult to achieve subsequent hemostasis. It constitutes a hazard for orthopedic surgeons especially in the anterior approach to the acetabulum. We carried out forty cadaver dissections (80 hemi-pelvises) through the ilioinguinal approach. A vascular anastomosis was found in 83% of specimens. Of these, 60% had a large diameter (>3 mm) channel along the posterior aspect of the superior pubic ramus. In clinical practice, however, 492 anterior approaches (to the best of our knowledge the largest series described) have been carried out over the last 15 years by the senior author (MB) and only five of these problematic vessels were discovered, and in only two cases was there troublesome bleeding. This study confirms a paradox: in anatomical dissections a large vessel was identified behind the superior pubic ramus, whereas in clinical practice this vessel does not seem to be as great a threat as initially perceived. Orthopedic surgeons planning an anterior approach to the acetabulum, such as the ilioinguinal or the intrapelvic approach (modified Stoppa), have to be cautious when dissecting near the superior pubic ramus. Despite the high prevalence of these large retropubic vessels in the dissecting room, surgeons should exercise caution but not alter their surgical approach for fear of excessive hemorrhage.

Acetabulum↗
PubMed1994

Vascular injury during total hip arthroplasty: the anatomy of the acetabulum.

We encountered a massive retroperitoneal haemorrhage due to perforation of the external iliac vein by a drill tip passing through the antero-superior quadrant of the acetabulum during cementless total hip arthroplasty. An anatomical study of the acetabulum was undertaken to determine the safe zones for transacetabular screw fixation. Five cadavera were studied to find the proper locations for screws using acetabular quadrants. The postero-superior and postero-inferior acetabular quadrants have good bone stock and are safe for the transacetabular replacement of screws. The antero-superior and inferior quadrants should be avoided. Screws placed in these quadrants may damage the external iliac artery and vein or the obturator vessels.

Acetabulum↗
PubMed1991

Experimental trauma of the triradiate epiphysis of the acetabulum and hip dysplasia.

Experimental traumatic lesions of the iliac and pubic parts of the triradiate cartilage of the acetabulum in young Wistar rats, were created to study the effect on the development of the hip joint. Radiological, functional and morphometric results were evaluated at twelve weeks of evolution, a time when the epiphysis was mature in a control series. Interference with the pubic growth plate caused acetabular dysplasia and dislocation of the hip. Both lesions caused deformities of the acetabulum and the femoral head. It is concluded that varied traumatic lesions of the triradiate cartilage may be of prognostic significance.

Acetabulum↗