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Results for “LEG LENGTHENING”

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PubMed2005

Results with navigated bicontact total hip arthroplasty.

The position of the cup is crucial for the overall quality of a total hip arthroplasty. A malpositioning of the cup leads to increased risk of dislocation, wear, and revision. The position of the stem influences leg length and may cause impingement and dislocation. These faults may increase with minimally invasive procedures. From November 2001 to June 2005, 1081 consecutive THA patients were evaluated. Cup navigation resulted in a better alignment and additional improvement when the cup and stem were navigated. In stem navigation, a good control of the leg lengthening and a reliable prediction of the safe range of motion could be seen.

Adult↗

PubMed2001

[The influence of osteotomy technique on distraction osteogenesis].

The authors reviewed the clinical results of leg lengthening by distraction osteogenesis, where two different osteotomy techniques were used: classical corticotomy according to Ilizarov or osteoclasis. Evaluation of results of 64 patients were bases on orthopedic examination and detailed X-ray analysis which included criteria assessing osseous regeneration rate. In those cases where osteoclasis was performed bone formation in the distraction gap was faster than in after osteotomy. An accelerated rate of regenerate formation, as well as a more active regenerate remodelling was observed. This allowed to shorten the time of external fixator application and an earlier rehabilitation.

Adolescent↗

PubMed2000

Micro CT and Micro MR imaging of 3D architecture of animal skeleton.

Quantitative assessment of three-dimensional (3D) trabecular structural characteristics may improve our ability to understand the pathophysiology of osteoporosis, to test the efficacy of pharmaceutical intervention, and to estimate bone biomechanical properties. Considerable progress has been made in advanced imaging techniques for noninvasive and/or nondestructive assessment of 3D trabecular structure and connectivity. Micro computed tomography (microCT) has been used to measure 3D trabecular bone structure in rats, both in vivo and in vitro. It can directly quantify 3D trabecular bone structure such as trabecular volume, trabecular thickness, number, separation, structure model index, degree of anisotropy, and connectivity, in a model-independent manner. We have used microCT to study ovariectomy (OVX) induced osteopenia in rats and its treatment with agents such as estrogen, and sodium fluoride. We have demonstrated that 3D microCT can quantify mouse trabecular and cortical bone structure with an isotropic resolution of 9 microm(3). It is also useful for studying osteoporosis in mice and in phenotypes of transgenic mice or gene knockout mice. MicroCT can be used to quantify osteogenesis in mouse Ilizarov leg lengthening procedures, to quantify osteoconduction in a rat cranial defect model, and to quantify cortical bone porosity. Recently, microCT using high intensity and tight collimation synchrotron radiation to achieve spatial resolution of 1-2 microm has provided the capability to assess additional features such as resorption cavities. Unlike microCT, micro magnetic resonance imaging (IMRI) is nonionizing. Recently, the ability of microMRI to assess osteoporosis in animal models has been explored. Using a small, high-efficiency coil in a high-field imager, microMRI can give resolutions sufficient to discriminate individual trabeculae. We have shown that, with appropriate settings, it is possible to image trabecular bone in rats in vivo and in vitro. In our study of OVX rats, analysis of microMR images can demonstrate differences in rat trabecular bone that are not detected by DXA measurements. In a rabbit OA model, with the OA induced by meniscectomy or anterior cruciate ligament transection, MRI shows decreased cartilage thickness, subchondral osteosclerosis and osteophytes, while radiographs can only show subchondral osteosclerosis and osteophytes could not be found. Advanced imaging methods are able to measure 3D trabecular structure and connectivity in arbitrary orientations in a highly automated, objective, non-user-specific manner, allowing greater numbers of samples for unbiased comparisons between controls and the disordered or treated. They can be utilized on a large sample leading to fewer sampling errors. They are non-destructive allowing multiple tests such as biomechanical testing and chemical analysis on the same sample; and non-invasive permitting longitudinal studies and reducing the number of animals needed.

Journal Article↗

PubMed1991

[Primary valgisation osteotomy in femoral neck fractures].

Technique and results after primary valgisation osteotomy in 41 patients with femoral neck fractures are described. 2 non unions and 9 avascular femoral head necroses were observed. The primary valgisation most probably does not influence the rate of necrosis. When performed by accurate technique it lowers the incidence of non union of the femoral neck. Postoperative leg lengthening is always evident. The most current avoidable mistake is an external rotational deformity. The procedure requires proper preoperative planning.

Adult↗

PubMed1991

[The characteristics of osteogenesis under conditions of stretch tension].

Structure of rough-fibrillar, netted and laminated bone tissues, formed in distraction regenerates on various stages of leg lengthening, was studied experimentally on dogs, using light, transmission and scanning electron microscopy and electron probe microassay. It was ascertained, that the first two types of tissues belong to the category of provisory, rapidly renewing ones, the volume increase of which is possible not only at the expense of appositional growth but also interstitially. Their formation in the area of the regenerate, more proximally and more distally than the medial layer, provided longitudinal growth of primary osteons forming here and thereby the growth of the whole bone regenerate.

Animals↗

PubMed1991

Somatosensory-evoked potential monitored during total hip arthroplasty.

One hundred consecutive patients were monitored using somatosensory-evoked potential (SEP) monitoring to detect intraoperative sciatic nerve compromise during total hip arthroplasty. The peroneal nerve was stimulated using the contralateral extremity to rule out systemic influences on the SEP tracings. Loss of amplitude or an increase in latency of greater than 10% was considered significant. Of the 18 patients who exhibited changes that met these criteria, 16 were female. Two patients had loss of amplitude of the tracings at the time of closure, and both of these patients exhibited postoperative sciatic nerve palsies. There were no false negatives. Femoral reaming and reduction are the surgical events most commonly associated with nerve reactions. Patients who have had prior hip procedures appear to be at higher risk. There was no correlation with intraoperative SEP changes and age, weight, surgical approach, or leg lengthening. Compared with unmonitored patients, there was no reduction in the incidence of sciatic palsy.

Evoked Potentials, Somatosensory↗

PubMed1989

[Comparison of surgical and conservative treatment methods as exemplified in the juvenile femur].

In a series of 329 children treated for fractures of the femur between 1968 and 1982 a comparison was made between the results of mere extension treatment against operative compression plate treatment. The follow-up shows that conservative methods suffer from high rate of axial deviation, particularly antecurvature, while operative treatment has the negative effect of a higher, incidence of persistent leg lengthening and of re-fracture. The advantages of operative management, namely precise positioning of fracture, low damage to soft tissue and - above all - unimpaired motility of the young patient justify its preferred use in the treatment of femur fractures in children - except for long oblique fractures.

Bone Plates↗

PubMed1983

[Experimental study of improved threading of bone screws].

In order to improve the holding force between the bone and the screw, we have been carrying out experimental investigations of the stability of bone and screw connection. Especially Schanz screws with a diameter of 6 mm, used in connection with the Wagner leg lengthening device, have been taken into consideration. By use of a loading model we determined the sizes of the essential kinds of loadability of the bone-screw connection and therefrom derive directions for dimensioning. The influence of the thread parameters (e.g. flank angle, pitch, pitch angle) on the loadability of the bone-screw connection has been investigated experimentally for 17 different thread profiles. Summarizing up the results, a pitch angle of 7,5 degrees and a flank angle between 12 degrees and 15 degrees proved to enable the maximum loadability. Corresponding to the results of our trials with the loading model, the improvement of the thread was carried out on the premises of simultaneous failure of both the cortical thread and the Schanz screws by pressure or shear. The loosening behaviour of the improved thread has been tested together with the conventional thread form. The results showed a reduction of about 20% in loosening of the screws and an increase of about 30% in pressure and traction loadability.

Biomechanical Phenomena↗

PubMedDate not supplied

Total hip and total knee arthroplasty in juvenile rheumatoid arthritis.

Total hip arthroplasty (THA) or total knee arthroplasty (TKA) is indicated for patients with juvenile rheumatoid arthritis (JRA) when marked joint destruction is present and pain or deformity compromises function despite optimal medical therapy. Relief of pain, reduction of the deformity, and dramatic improvement in functional status and quality of life can be achieved in most patients. Functional impairment and deformity rather than pain are usually the primary indications for THA or TKA. When there is both hip and knee involvement, hip arthroplasty should probably be done first. Regional anesthetic appears to be the anesthetic of choice. Careful preoperative planning and the availability of custom and minisized components are essential. Small bone size, osteoporosis, and severe soft tissue disease make the surgery technically demanding. Skeletal immaturity may not contraindicate surgery if the patient is otherwise bedridden with progressive deformity. In the hip trochanteric osteotomy is often necessary for adequate exposure, with the possible exception being a patient with juvenile ankylosing spondylitis who is subject to heterotopic bone formation. Although complete capsulectomy and psoas tenotomy may be necessary to relieve a hip flexion contracture, a soft tissue release that produces leg lengthening may lead to nerve palsy. In the hip component loosening has been less common in patients with JRA than in other young patients who have undergone THA, but it is still the most frequent cause of failure. In the knee preoperative and postoperative serial casts can aid in the correction of severe flexion contracture. Secondary patellar pain has been the most common cause of late failure. Patellar resurfacing should probably be performed at the time of the original knee arthroplasty in all patients with JRA.

Adolescent↗

PubMed1980

[Participation of bone marrow stromal precursor cells and bone regeneration during transosseous osteosynthesis].

Changes in the proliferative activity and in the number of bone marrow stromal precursor cells (SPC) in the dog long bone fixed with Ilizarov's apparatus were studied by cloning in monolayer cultures over a period of leg lengthening. It was demonstrated that in 1-1 1/2-year-old dogs the number of dividing SPC in the tibia increased up to 95% by termination of the distraction (60 days). Concurrently, the colony-forming efficiency (CFE) increased 11-fold. In the contralateral tibia (CFE significantly rose during the distraction, while in the humeri it decreased 2.5-fold as compared to control. A conclusion is drawn about participation of SPC in bone regeneration.

Animals↗

PubMedDate not supplied