The authors review current knowledge regarding the use of ceramic materials in prosthetic hip surgery, both as constituents of prosthetic components, and as materials used to coat metallic surfaces. A review of the literature defines the advantages and disadvantages to using ceramic-polyethylene or ceramic-ceramic combinations, based on the possibility that alumina coating may favor localized bone demineralization, and on the first promising clinical results of the use of hydroxyapatite coating.

Aluminum↗

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Computerized morphometric analysis of the femoral diaphyseal canal.

The constant increase in the use of hip arthroplasty and the continuous search for the best possible adaptation of the implant to femoral anatomy have led to the development of methods of radiographic analysis that are increasingly precise and reliable. Among these the methods that include the use of traditional radiograms-despite their limits-deserve a place of importance. In fact, these methods offer the advantage of being easy to apply and of allowing for a comparison to be made with pre-existing files. Computer science is useful in this field, in particular, computerized analysis, both morphometric and statistical, of the data acquired by digitizer. The protocol of acquisition and analysis that we applied to x-rays in anteroposterior view allowed for an evaluation to be made of some of the morphologic parameters of 354 femurs (corresponding to 264 patients), relating them with the pathologies that led to hip arthroplasty. The duration of a cementless hip prosthesis strongly depends on primary stability. For this reason, an ever-increasing number of studies tends to make a precise evaluation of the morphology of the joint, in order to obtain excellent contact between bone and prosthetic component. The methods used are essentially radiological, with the use of computerized tomography and stereophotogrammetry. Morphometric studies of the proximal femoral area have in particular considered the width of the medullary canal at various levels; the cervico-diaphyseal angle; the flare index of the femoral canal (relationship between the internal metadiaphyseal diameter and that of the isthmus) and the distance between the rotation center of the femoral head and the diaphyseal axis. The evident absence of proportion between femoral sizes and shape of the medullary canal has led to the search for parameters capable of describing in simple fashion the shape of the femoral diaphyseal canal. A good describer of femoral morphology is the flare index, that allows for classification of the various shapes of the diaphyseal canal in three families: "stove-pipe like", "normal", "champagne glass like". The distinction between these groups is not clear, as the passage from one shape to another is gradual. The idea of obtaining more knowledge on femoral morphology, also to the purpose of determining possible new criteria that may be of help in preoperative planning and in the choice of a model to be implanted, has suggested our study on modifications caused by some of the pathologies that most frequently lead to arthroplasty.

Adult↗

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Diagnostic protocol in prosthetic loosening.

The authors report the results they obtained in 35 cases studied based on a protocol to identify prosthetic loosening and to preoperatively establish its possible septic etiology. After clinical and radiographic assessment, the protocol called for a total body bone scan with Tc 99 m which, in positive cases, were associated laboratory tests and further instrumental testing (CT, bone scan and needle aspiration). Thanks above all to bone scan with labelled granulocytes the protocol provided high accuracy (91.4%) in preoperatively identifying the causes of infection.

Clinical Protocols↗

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Indications for prosthetic reimplantation.

It is difficult to establish on the basis of rigorous criteria when a prosthetic implant must be considered loosened, but it is even more difficult to define with certainty whether a loosened prosthesis must be reimplanted, and particularly when it is necessary to act. The authors emphasize the need to act quickly every time there is loss of periprosthetic bone substance that progresses in time, and that may make anatomical reconstruction difficult.

Hip Prosthesis↗

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Which length for the revision stem?

The results of 79 stem implantations performed between 1981 and 1992 are presented. Mean clinical and radiographic follow-up was obtained 36 months after surgery. All of the prostheses were substituted due to aseptic loosening: of these 68% were cemented. Femoral osteolytic lesions secondary to loosening was classified based on the Paprosky protocol. A severe femoral osteolytic defect (type 2b, 2c or 3 according to Paprosky) was associated with 4% of the cases of loosened cementless prostheses, and with 37% of the cemented ones. Homoplastic bone grafts were used in 40% of the patients. The length of the stems used for reimplantation was short (12-13 cm) in 43%, standard (17-18 cm) in 49%, and long (> or = 22 cm) in 7% of the cases. These stems were cemented in 32% of the cases. The incidence of cementation was different in relation to length, as 62.5% of the short stems were cemented, as compared to 5.3% of the stems of standard length. Clinical results were excellent in 90% of the cases submitted to surgery with short stems, in 80% of those treated with standard stems, and in 50% of the cases of revision surgery where long stems were used. Radiographically, 97% of the short stems were osteointegrated, as compared to 94% of the standard stems and to 25% of the long ones, which were only used in a very few cases to be considered quite complex ones.

Bone Cements↗

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Indications and limits of acetabular reimplantations using screwed prostheses.

The clinical and radiographic results of 95 acetabular reimplantations performed between 1984 and 1992 are presented. A screwed acetabular prosthesis was used in 56 patients, the acetabulum was cemented in 15, and a press-fit acetabulum stabilized by screws (1 case without screws) was used in 24. Mean clinical follow-up was 35.6 +/- 24 months, ranging from 7 to 94 months. Clinical results were good and excellent (> or = 5 points according to Merle D'Aubigné) in 77% of the cases for pain, in 70% for walking, and in 71% for joint movement. Forty months after surgery 48% of the screwed acetabula and 44% of the cemented ones were osteointegrated. The incidence of loosening for the screwed acetabula was 24%. The preliminary results 24 months after the press-fit acetabula with screws had been inserted showed 100% osteointegration. Radiographic results of the screwed acetabula were satisfactory (92% osteointegration) only in reimplantations performed in patients with minimum acetabular osteolytic injury (Paprosky types I and IIA). The use of homoplastic bone grafts did not improve the radiographic results of the screwed acetabula in the cases with severe osteolysis: 57% of the acetabula screwed on grafts distributed throughout the acetabulum were, in fact, loosened.

Acetabulum↗

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Techniques for removal of the stem: transfemoral or intramedullary?

Since 1981 a total of 76 reimplantations of the prosthetic stem have been performed, substituting 52 cemented stems and 24 cementless ones. Only 7 patients (9%) required transcortical access, 3 of these stems (43%) were not osteointegrated, while of the 69 reimplantations performed by intramedullary approach, only 4% of the stems did not achieve skeletal stabilization. A total of 43% of the stems reimplanted using an intramedullary approach were short (12-13 cm). The advantages of intramedullary access may be summarized by saying that diaphyseal cortical bone is saved; in the use of short prosthetic models. The transcortical technique is limited to a minority of patients, particularly to cases where stems that show osteointegration and are cementless are removed.

Bone Marrow↗

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Lateral retrovascular approach to the upper cervical spine.

The authors describe the surgical anatomy of lateral approach to the upper cervical spine. The approach is retrovascular retropharyngeal extraoral allowing for anterolateral exposure of the upper cervical column, and it may be enlarged posteriorly on the homolateral posterior hemiarch of C1 and C2, and/or inferiorly on the lower cervical column. Absolute indications to this approach are anterolateral fusion with transarticular screws C1-C2 and excision of skeletal neoplasms adjacent to the vertebral artery. For other indications such as the treatment of anterior neoplasms and spinal cord decompression it is preferable to use pre-vascular extraoral approach or transoral approach.

Adolescent↗

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Arthroplasty in the ankylotic hip.

A total of 30 cases submitted to arthroplasty for the treatment of ankylotic hip are reported. The clinical results show that movement improved in 63% of the cases, with recovery of normal joint excursion in 37%. Severe limping consequent to hypotrophy of the gluteal musculature persisted in 62% of the cases, requiring the use of two canes in 17% of the patients. There was pain < or = 3 based on the Merle D'Aubigné and Postel evaluation scale in 13% of the patients, while 87% remained totally asymptomatic. Radiographic results were favorable: the incidence of aseptic loosening 86 months after surgery in 25 cemented prostheses was 20% for the acetabulum and 12% for the stem, while the 5 cementless prostheses were stable an average of 27 months after surgery. The incidence of aseptic loosening was greater in patients < or = 45 years of age (30% vs 10%). Early complications included dislocation (6.6%), caused by hypotrophy of the gluteal musculature secondary to the ankylosis. Leg length discrepancy, which was present preoperatively in 10 cases with an interval ranging from -5 to 6 cm (mean 3 cm), was corrected in 6 cases and reduced by half in the remaining 4 patients.

Adult↗

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A computerized morphometric evaluation of x-ray films for preoperative planning of hip arthroplasty.

Methods for measuring metric size on radiograms constitute an instrument of proven utility. For example, when preoperatively evaluating hip arthroplasty the diameter of the medullary canal and the cervicodiaphyseal angle, must be measured in order to determine the center of rotation of the femoral head, and to establish the flare index of the diaphyseal canal. These results may be obtained by using a computer-controlled graphic table to place the coordinates for the areas of greater anatomical and physiological importance on the radiologic image. Thus, a calculation of distances, anatomical axes and angles is obtained immediately, accurately defining the morphometry of the joint. In this study, the anteroposterior preoperative radiographic views of 87 femurs in 84 patients were evaluated by this method. The values provided by the morphometric analysis were then related to sex, age and weight. The diaphyseal canal was classified by typology for the preoperative planning of hip arthroplasty.

Adult↗

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Failed back syndrome: a study on 95 patients submitted to reintervention after lumbar nerve root decompression for the treatment of spondylotic lesions.

The persistence of lumbar and nerve root pain after nerve root decompression surgery may be attributed to one of five causes; 1) progression of the spondylotic disease in the presence of peridural fibrosis; 2) recurrence of disc herniation or new hernia; 3) stenosis of the spinal or nerve root canal; 4) arachnoiditis; 5) vertebral instability. In most patients with peridural fibrosis and worsening of spondylotic lesions regression of nerve root symptoms was obtained after several months of conservative treatment, which continues to constitute essential treatment for most patients with recurrence of lumbar symptoms. The authors report the results obtained with the surgical treatment of 95 patients performed between 1981 and 1991 and divided into the categories listed above. Of these patients, 70 were submitted to further decompression surgery while 25 were submitted to posterolateral vertebral fusion. Reintervention obtained useful results in 83% of the cases where there had been recurrence of disc herniation; nerve root release obtained positive results in 100% of the cases where there was stenosis. Results obtained after wide decompression were poor in all of the cases with arachnoiditis; in these patients conservative treatment with T.E.N.S. can obtain a fair amount of control over pain. Positive results were obtained in 84% of the 25 patients submitted to posterolateral fusion for the treatment of vertebral instability, with fusion obtained in 96% of the cases. Surgical treatment is indicated for psychotic, neurotic patients or those with insurance-related motivations only when the organic cause of the symptoms is clearly evident.

Adolescent↗

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Caso quiz. Degenerative spondylolisthesis at L4.

Explore the source record for details and available documents.

Adult↗

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Differential diagnosis of low back pain.

Low back pain is a symptom common to many vertebral and extravertebral affections. The origin of low back pain mostly derives from a pathology localized in the spine, as in the case of degenerative lesions, neoplastic lesions, infections, fractures, metabolic diseases such as osteoporosis, or more rarely, rheumatological diseases. The causes of extravertebral low back pain may be renal, pancreatic, gastrointestinal, or of the female genital apparatus. The authors present a series of clinical aspects which must always be taken into consideration in order to avoid errors in the diagnosis and evaluation of a patient with low back pain.

Diagnosis, Differential↗