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Biomedical subjects

D Mainard

Publications and source records attributed to D Mainard.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Flatfoot].

The flat foot is a very frequent cause of consultation in podology. The lesion is rapidly fixed, and osteoarthrosis appears. The diagnosis is clinical. A podoscopic and radiographic examination is necessary to appreciate the evolutivity of the deformity. The treatment is almost conservative: the wearing of orthesis is often sufficient. The indications of the surgery are rare; sometimes it is possible to do plastic techniques (in particular on the posterior tibial tendon) but, when the foot is painful, the osteoarthrosis is present and it is necessary to do arthrodesis, in particular in the talonavicular joint.

Adolescent↗
PubMed1997

[Current treatment of static deformities of the great toe].

The modern techniques of treatment of the hallux valgus are founded on the biomechanic and permit to give again a good function of the big toe. The authors prefer the osseous methods and specially the phalangeal and metatarsal osteotomies. It is necessary also to do a lateral release of the metatarsophalangeal joint and an exostosectomy. The late results are good.

Adult↗
PubMed1996

Stereoselective distribution of tiaprofenic acid in synovium and cartilage in osteoarthritic patients.

OBJECTIVE: In order to document the stereoselective distribution in joints of a chiral nonsteroidal anti-inflammatory drug, the relative affinities of the enantiomers of tiaprofenic acid in synovium and for cartilage were compared. METHODS: The distribution of tiaprofenic acid in synovium and in cartilage was studied 25 h after administering the racemic drug for 2 days (600 mg of a sustained-release preparation, once daily), in 12 inpatients with osteoarthritis of the hip requiring arthroplasty. Enantiomers were quantified in plasma and freeze-ground tissues by a chiral HPLC assay. RESULTS: Plasma concentrations of the dextrorotatory (R) enantiomer (0.40 microgram/ml) were higher than those of its antipode. The concentration of racemate in synovium (in dried and fresh tissues, 150% and 40%, respectively, of the concentration in plasma) was much higher than that in cartilage (in dried tissues 32% of the plasma concentration). The ratio of the active, dextrorotatory (R) enantiomer to its antipode was higher in synovial tissue than in plasma. CONCLUSION: Tiaprofenic acid is distributed stereoselectively in plasma and synovium, which contain a higher concentration of the active, dextrorotatory (R) enantiomer. In cartilage, it reaches only a very low concentration.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Evaluation of the effect of three surface treatments on the biocompatibility of 316L stainless steel using human differentiated cells.

AISI 316L stainless steel (SS) is widely used in orthopaedic implantology, although biological complications may result from its insufficient mechanical and tribological properties. In order to improve the wear and corrosion resistance as well as the hardness of 316L SS, three surface treatments, derived from those applied in mechanical engineering industries, were investigated: (1) glow discharge nitrogen implantation, (2) carbon-doped stainless steel coating sputtering and (3) low temperature plasma nitriding. Surface characterization according to the different heat treatments showed that corrosion and wear resistance were strongly improved, especially by ion implantation or carbon-doped SS coating sputtering. In the same way, microhardness was significantly increased after the three treatments. The effect of such treatments on the biocompatibility of 316L SS was studied with human osteoblast and fibroblast cultures. Basic and specific features of the cells showed that ion-implanted and carbon-doped stainless steels were biocompatible, whereas dramatic cellular reactions were noted when contacted with nitrided stainless steel. A hypothesis is given to explain this observation but further experiments are needed to optimize the nitriding process. Nitrogen implantation and carbon-doped layer deposition could be efficient means for improving the physical properties of stainless steel without affecting its biocompatibility. Such surface treatments may have relevance for increasing the life time of 316L biomedical devices.

Alkaline Phosphatase↗
PubMed1996

Cytocompatibility of Ti-6Al-4V and Ti-5Al-2.5Fe alloys according to three surface treatments, using human fibroblasts and osteoblasts.

Titanium alloys are well known for their superior mechanical properties as well as for their good biocompatibility, making them desirable as surgical implant materials. However, these alloys have been proven to behave poorly in friction since wear particles were often detected in tissues and organs associated with titanium implants. In this paper, three surface treatments were investigated in order to improve the wear resistance and the hardness of Ti-6Al-4V and Ti-5Al-2.5Fe: (a) glow discharge nitrogen implantation (10(17) atoms cm-2), (b) plasma nitriding by plasma diffusion treatment (PDT) and (c) deposition of TiN layer by plasma-assisted chemical vapour deposition (PACVD) additionally to PDT. Surface characterization after the different treatments showed considerable improvement in surface hardness, especially after the two nitriding processes. Moreover, the good corrosion resistance of untreated alloys was maintained. A cell culture model using human cells was chosen to study the effect of such treatments on the cytocompatibility of these materials. The results showed that Ti-5Al-2.5Fe alloy was as cytocompatible as the Ti-6Al-4V alloy and the same surface treatment led to identical biological consequences on both alloys. Nitrogen implantation did not modify at all the cellular behaviour observed on untreated samples. After the two nitriding treatments, cell proliferation and viability appeared to be significantly reduced and the scanning electron microscopy study revealed somewhat irregular surface states. However, osteoblast phenotype expression and protein synthesis capacity were not affected. PDT and PACVD may be interesting alternatives to the physical vapour deposition technique.

Alkaline Phosphatase↗
PubMed1996

[The Staca nail-plate in the treatment of trochanteric fractures].

PURPOSE OF THE STUDY: The Staca nail-plate (SNP) is 32 years old. This implant was created by Descamp and Kerner from Nice in 1964. This study evaluates the experience with the SNP in two Orthopaedic Departments from Metz and Nancy Regional Hospitals, between January 1989 and July 1991. MATERIAL AND METHODS: This is a clinical and radiological retrospective study. Out of the 175 patients, 152 were reviewed at 3 months and 127 at more than 9 months. The radiological assessment was made by measuring the post-operative cervical angle, the position of the nail within the femoral neck, the inter-fragmentary distance and the distance between nail and femoral head cartilage. 175 trochanteric fractures (119 women and 56 men) had osteosynthesis with the SNP. The mean age was 79 years (range: 36 to 96 years). Only 29 patients were free of general associated pathology. The fracture was always traumatic. The right femur was involved in 97 cases. Following the Ender classification there were 87 stable and 88 unstable fractures (59 complex pertrochanteric, 19 inter and sub-trochanteric and trochantero-diaphyseal). RESULTS: Post-operative reduction was anatomical in 66 per cent and satisfactory in 89 per cent of cases. In three cases there was an acetabular protrusion of the nail, in two cases there was a varus reduction and fixation and in six cases the plate was not fitting correctly the diaphysis. The average per-operative blood-loss was 300 cc. There was one per-operative death and eight early post-operative deaths. Sitting was allowed 24 hrs, after surgery in 94 per cent of patients. 68 per cent of patients started walking within the first 15 days after surgery. There were 37 per cent general complications, mainly respiratory and urinary infections, but also 2 deep-vein phlebitis, with pulmonary embolism and death. 17 post-operative hematoma were noted, out of which two required surgery. The general mortality reached 15 per cent in three months and 22 per cent in nine months. 70 per cent of the patients were free of pain at 3 months and 78 per cent at 9 months, 65 per cent being able to walk without crutches. Nail acetabular protrusion was observed in 16 cases (3 in early post-operative period, 8 within three months and 2 between the third and the ninth month). The protrusion was related to the nail positioning in 11 out of the 16 cases. This complication required SNP removal in 7 cases, replacement of the SNP in 3 cases and total hip arthroplasty in two cases. Correct nail length assessment is the important step in order to avoid protrusion and has to take into account the interfragmentary distance after reduction (if any). A good per-operative nail impaction is mandatory. CONCLUSION: Compared to other implants (THS, DHS, Gamma-nail, Ender), the SNP gives comparable results and a stable fixation. The SNP is a reliable implant. The most common complication in our series is protrusion which required reintervention in 6.8 per cent of the cases. Currently we avoid this complication by a good per-operative nail impaction.

Adult↗
PubMed1996

[Quality of life after orthopedic surgery of the lower limbs. A new approach].

Measuring quality of life is a new approach of interest to all health professionals involved in orthopedic surgery. This paper is an introduction to the multidimensional concept of health related quality of life. Various types of measurement instruments are described: first the psychometric questionnaires, distinguishing generic measures useful in various conditions and disease-specific measures for a given disease or condition, and the recently developed individual instrument; second, econometric measures based on the decision theory. The potential objectives for use and the required measurement properties of these instruments are described. The need and corresponding methods for a cross-cultural adaptation into French when using questionnaire originally developed in English are reported. A literature review focuses on studies reporting such measures used to evaluate orthopedic surgery, particularly in the way patients perceive the results of hip and knee arthroplasty. Further perspectives for clinical and epidemiological research are numerous. Several avenues for research and for use in clinical practice are proposed.

Decision Support Techniques↗
PubMed1995

Magnetic resonance imaging may be an asset to diagnose and classify fluoroquinolone-associated Achilles tendinitis.

The aim of this study was to document the accuracy of magnetic resonance imaging (MRI) during fluoroquinolone-associated Achilles tendinitis. Fourteen Achilles tendons were examined by MRI (T1 and T2 or T2*-weighted sequences) in nine patients with typical tendinopathy (13 cases of tendinitis and 1 rupture) during fluoroquinolone therapy. Tendinous involvement was classified according to the prominence of intra- or peritendinous changes. The most typical feature was the presence of intratendinous changes, longitudinal or transversal, detected on T1 or T2-weighted sequences. Peritendinitis was most visible in two cases and nodular involvement in three cases. It was concluded that MRI appears a helpful and accurate method in identifying and classifying such iatrogenic tendinitis. In addition, MRI indicates orthopedic management when detecting risk of rupture.

Achilles Tendon↗
PubMed1995

Antivitamin K prevents heterotopic ossification after hip arthroplasty in diffuse idiopathic skeletal hyperostosis. A retrospective study in 67 patients.

We investigated the risk of heterotopic ossification (HO) after total hip arthroplasty in 67 patients, 16 of whom had diffuse idiopathic skeletal hyperostosis (DISH). DISH was diagnosed on chest, dorsolumbar and pelvic radiographs. HO was graded according to DeLee et al. (1976). After a 1.4 year follow-up, 21 patients had HO. The risk of HO was 5 times higher in DISH than in non-DISH patients, but lower in patients receiving antivitamin K than in those receiving other anticoagulant therapy (relative risk 0.2). Our findings lead us to recommend that DISH should be diagnosed preoperatively for preventive therapy. They also suggest a preventive effect of antivitamin K against heterotopic ossification after hip arthroplasty.

Acenocoumarol↗
PubMed1995

[Imaging of osteomedullary infarctions and their complications].

Radiographic, CT, bone scan and MR patterns of the infarcts of the metaphyses and diaphyses of tubular bones and their main complications are presented. Bone marrow infarcts are located in the medullary cavity of long bones. They most often involve the lower limbs. They are commonly associated with necrosis of the epiphyses and have common origin. In contrast to necrosis of the epiphyses, bone infarcts may present specific complications. They are most often detected incidentally, because of their clinical latency. Radiographic and CT changes appear late, showing localized areas of increased density with irregular rims, or sharply demarcated shells of calcification. Earlier changes are demonstrated by bone scan and MRI. MR pattern is characteristic, showing an area of hyposignal on T1- and T2-weighted sequences, with irregular rims, and sometimes small areas of fat signal. Their complications include cystic formation and malignant degeneration (sarcoma and particularly malignant fibrous histocytoma). An unusual complication, infection involving bone infarcts is also presented.

Bone Cysts↗
PubMed1995

[Double use of sural fascio-cutaneous flap with distal pedicle to cover loss of substance of ankle or heel].

The authors report on a case of a distally based fascio-cutaneous flap from the sural region which has been used twice to cover two different cutaneous sites of an ankle. A 50 years old patient underwent a polytrauma including an open fracture of the ankle. The wound at the anterior aspect of the ankle did not heal and the cover by a distally based fascio-cutaneous sural flap was decided and realized successfully. Three weeks later, owing to the development of an ulcer of the heel, it was decided to cover this skin ulceration with the same distally based flap. This second procedure needed a complementary dissection at the bottom of the flap. Twenty days later, the remaining flap was put back and the uncovered donor site was skin-grafted. The two sites covered by the flap healed, without any further complications. They only benefited in the following months of plastic revision to improve their shapes. In the discussion the authors remind the anatomic basis of this distally based flap, described by Donsky and Fogdestam in 1983. They also discuss the other possibilities to cover these two lesions on the same ankle, using others flaps particularly the lateral supra malleolar flap described by Masquelet, the medial plantar island skin flap described by Harrison and Morgan, the lateral calcaneal skin flap described by Grabb and Argenta and the neuro-vascular island skin flap proposed by Masquelet et al. This clinical case emphasizes on the great interest of the distally based sural flap in the cover of the skin defect of the ankle. The flap is easy to raise and offers a great available skin surface, which can be used, as demonstrated by this original case, in two different sites of the ankle.

Ankle↗
PubMed1995

[Macroscopic, histologic and ultrastructural study of 89 prostheses of anterior cruciate ligament excised because of prosthesis failure].

PURPOSE OF THE STUDY: This study concerns the etiology of failed synthetic anterior cruciate ligament (ACL) prostheses, and attempts to identify the primary mechanisms that lead to their premature rupture. MATERIAL AND METHODS: A total of 89 failed and surgically excised ACL prostheses were retrieved from young and active patients (27 +/- 7 years) at various orthopaedic centres in France. Their average duration of implantation was 34 +/- 24 months. They were examined macroscopically, histologically and by scanning electron microscopy (SEM) to determine the model, the manufacturer, the surgical technique used at implantation, the extent of healing, the site of rupture, as well as the morphology of the damage fibers. RESULTS: Seventy two of these explants represented 6 different models. While all 6 were fabricated from polyester fibres, each had a different textile construction, and each were associated with a unique healing and mechanical response in vivo. SEM observations confirmed that abrasion of the textile fibres were a phenomenon common to all models, and were the primary cause of prosthesis failure. Such wear zones were particularly prevalent at the exit of the tibial tunnel and around the femoral condyle. Collagenic infiltration into the synthetic ACL was poorly organized and unpredictable. It did not increase with the duration of implantation. In fact in certain models, it appeared to have caused deterioration and fraying of the textile structure rather than serving as a reinforcing matrix around the prosthesis. DISCUSSION: A synthetic ACL prosthesis is to be preferred for patients who do not have tissue available for autologous ligamentoplasty. Yet none of the synthetic devices examined in the present study were capable of stabilizing the knee over the long term. Among the factors that influenced their failure we found that the three most common mechanisms were flat abrasion against an osseous surface, flexural and rotational fatigue of the fibres, and loss of integrity of the textile structure due to unpredictable tissue infiltration during healing. CONCLUSION: The results of the present study show that none of the current models succeed in replacing the natural ACL. Future improvements may be achieved by developing surgical procedures for implantation combined with a prosthesis made from fibres and textile structures which are more abrasion resistant and promote predictable and controlled tissue infiltration.

Adult↗
PubMed1994

Fungal arthritis due to Pseudallescheria boydii (Scedosporium apiospermum).

Musculoskeletal infections by fungal agents are uncommon conditions. Pseudallescheria boydii is an ubiquitous saprophytic fungus frequently involved in maduromycosis but rarely in septic arthritis. We describe a case of Pseudallescheria boydii destructive suppurative arthritis and osteomyelitis of the knee in an adult Guadeloupean man. Osteoarticular infections due to Pseudallescheria boydii are reviewed.

Arthritis, Infectious↗
PubMed1993

[Scanning electron microscopy and microcrystals in articular diseases].

The value of scanning electron microscopy (SEM) in the study of crystals in articular diseases is underlined in several cases of examination of joint fluid, or crystal deposits in articular or periarticular tissues obtained by percutaneous or surgical treatment with chemical and crystallographic correlations. Apatite crystals. Two deposits of hydroxyapatite of the rotator cuff were studied by SEM, crystallographic techniques and chemical analysis. SEM study showed spherical aggregates of various size. Urate crystals. Three tophi were observed by SEM, with crystallographic techniques and chemical analysis. Their needle-shape and their great size (20 m) were characteristic. Calcium pyrophosphate crystals. In a case of typical clinical and radiological features, examination of joint fluid, with chemical correlation showed shorter and thicker crystals than those or urate. The precise identification of crystals is based on sophisticated crystallographic techniques such as X-ray diffraction, although SEM allows an accurate and quite simple morphologic study, most often sufficient.

Apatites↗
PubMed1992

Acute haematogenous osteomyelitis of the patella revealed by a pathological fracture in multiple myeloma.

A 57-year-old man was followed up for multiple myeloma with no lytic bone lesions. During a septicaema, he presented with a pathological fracture of the patella. Despite a poor haematological status, he received surgical treatment, which allowed diagnosis of haematogenous osteomyelitis of the patella. The outcome was favourable, with a 6-week plaster immobilization after cerclage and 4 months of intravenous antibiotic therapy. This case emphasizes the fact that one well-known cause of bone lesions may lead to an erroneous diagnosis. The successful clinical course suggests that accurate therapeutic management may be discussed in haematological malignancies when intensive-care support is available.

Acute Disease↗
PubMed1992

[Preparation of a polymer named Porimid, and its sterilization].

From a concrete example, the authors remind the interest to envisage the possibilities of sterilization as early as the initial period of a research about biomaterials. Indeed certain kinds of sterilization may be too much aggressive for biomaterials, especially the polymers, whom the structure is so impaired. These biomaterials may become ineffective even dangerous and blight a long time of research. The authors also expose the necessity to respect the good manufacturing practices of laboratory and the rules of hospital hygienics which is indispensable for all the members of the teams which participate to biomedical or clinical researches. A condition for the respect of these rules is the utilization of a common and well understood language between the medical and no medical teams.

Biocompatible Materials↗