PubMed Health⌕ Search

Biomedical subjects

D Poitout

Publications and source records attributed to D Poitout.

At least 19 recordsLinked to original sources
PubMed1992

[Analysis of stress in the knee using the finite element method].

The increase in the number of the studies of the stress around the anatomic prosthesis by the finite element method incited the authors' work. Our purpose was to study the methodology of a technic with simple cases. The finite element method is a method of calculation which allow the calculation of the displacement under the stresses of each element that we created in the structure. Before this calculation, we needed to define the exact geometry of the structure, the elementary properties of the material and the conditions of the experimentation, particularly the strains that exist in the structure. Three simple examples are given: an osteosynthesis plate with an hole, a knee model that Maquet studied with the photoelasticimetry method and a bidimensional knee model. The results are traduced by different colours or by coloured ligns. The conclusion is to warn the orthopaedic surgeons to look carefully what model is behind the pretty coloured results.

Biomechanical Phenomena↗
PubMed1991

[Massive osteocartilaginous allografts in the treatment of articular necrosis or loss of substance].

The problem of articular reconstruction arises increasingly often during the treatment of bone tumors because of the progress made in the choice of the chemotherapy. The excellent tolerance of osteocartilaginous allografts allows extending their indications to common traumatology. The biological, immunological, mechanical and clinical studies offer encouraging prospects in the field of massive osteocartilaginous grafts. Massive prosthesis are also used more and more often in case of recurrence or of prosthesis detachment. They may benefit from these techniques by using a sheath made of bank bone. These grafts allow increasing the stock of bone, which was so far constantly decreasing on the occasion of successive operations.

Bone Neoplasms↗
PubMed1991

[X-ray computed tomography or MRI in the assessment of bone tumor extension].

Conservative surgery of primary bone tumors, which has become possible owing to the progress made by chemotherapy, must be carcinological, and it is therefore based on a thorough assessment of local tumor extension. CT and MRI have proven their great value for this assessment. While CT clearly shows the calcified tissue and the extension into soft tissue, MRI is more effective to delineate the tumoral and intraosseous margins and, more importantly, for the exploration within bone, for which it has the advantage of making a study in all planes possible. The anatomical substrate and exact meaning of the MR signal of pathological tissue still remains to be specified. However, MRI already appears to be the essential examination for the assessment of local bone tumor extension. If it did not have contraindications, it could replace CT within the next few years.

Adolescent↗
PubMed1990

[Total or partial iliac reconstruction using allografts from the bone bank].

The reconstruction of massive pelvic defects following resection for tumour or damage from major trauma presents great technical difficulty. We have used cryopreserved allografts in patients to restore the normal anatomy and avoid major resection, such as a hemipelvectomy. This method avoids major limb shortening and impairment of function which occurs after trochantero-iliac or trochantero-sacral arthrodesis. Resection of tumour must be meticulous and complete in order to achieve a sound bed for the allograft. No problems were encountered in reattaching muscle insertions to the allograft, and skin healing was achieved without difficulty in all cases but one. In 2 patients involvement of nerve roots by tumour required their resection, with paralysis of the affected limb, but the overall function was satisfactory. In 10 patients removal of the hip joint was needed, and a total replacement was undertaken with cementing of the acetabular component into the allograft. Only one patient required a further operation because of partial necrosis of the allograft. Demineralisation was noted in some parts of the allograft between 18-20 months, but did not appear to affect function.

Adult↗
PubMed1987

[Use of allografts in oncology and traumatology].

Fresh allografts of bone are commonly used for repairing small defects, but preserved grafts are required for replacing large sections of long bones. We have collected these grafts in sterile conditions and then preserved the specimens in liquid nitrogen at minus 196 degrees Celsius. Biological, histological and biomechanical studies have confirmed the value of this technique. The method preserves the normal architecture of bone and viable cartilage cells. The medullary cells are gradually destroyed in situ leaving a protein matrix to which mineral components are fixed. Neither of these are antigenic in allografts and immunological problems are rarely encountered. When the recipient site is well vascularised the graft becomes fully integrated within two or three years. Doubt has been expressed as to the functional viability of the cartilage in large allograft joint replacements, and is has been suggested that metal prostheses might be better. Research is in progress in the use of ligament allografts and on the use of bank bone with large prostheses. The functional results are satisfactory in more than 90% of patients treated with these large allografts.

Adolescent↗
PubMed1981

[Assessment of activity in bone tumours by telethermography (author's transl)].

The assessment of activity in bone tumours after irradiation is somewhat uncertain. In most cases, the process of healing cannot be assessed. The authors propose the use of tele-thermography, which was used 14 patients. In 8 cases, amputation was performed when tele-thermography showed persistent activity. In all cases, secondary microscopic examination of the amputated limb showed remaining active tumour in spite of negative radiological appearances. In 6 cases, in which tele-thermography was negative, the limb was not amputated with no recurrence up to the present time. The follow up study has varied from 15 months to 5 years. The authors consider that this technique is of great value in the assessment of the activity of irradiated sarcomata.

Amputation, Surgical↗