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Biomedical subjects

P F Leyvraz

Publications and source records attributed to P F Leyvraz.

At least 19 recordsLinked to original sources
PubMed2007

Impact of family structure on long-term survivors of osteosarcoma.

GOALS OF WORK: Long-term outcomes of osteosarcoma have dramatically improved with the use of modern combination therapies. Such aggressive treatments, however, entail chronic complications. In the present study, we assessed the functional, psychological, and familial status of long-term survivors of osteosarcoma treated at our institution. MATERIALS AND METHODS: Fifteen long-term survivors of osteosarcoma were evaluated for functional and psychological sequelae. Functional assessment was based on a method described by Enneking et al. Psychological assessment was based on General Health Questionnaire 28, Inventory Scale for Traumatic Neurosis, and Family System Test. MAIN RESULTS: Ten patients showed mild functional impairments; only five patients were handicapped more seriously. Depressive symptoms were diagnosed in four patients. A total of six patients revealed unbalanced family structures, including three of the four patients with depressive symptoms, all four patients with symptoms of posttraumatic stress disorder, and five of seven patients who showed poor emotional acceptance. CONCLUSIONS: Osteosarcoma survivors will generally recover good functional performance. Only a minority of them remain seriously impaired. One third of the patients present depressive symptoms and posttraumatic stress disorder. Poor coping is closely associated with unbalanced family structures. Therefore, the psychological and familial situation of patients with newly diagnosed osteosarcoma should be carefully assessed.

Adolescent↗
PubMed2005

Computer-assisted two-dimensional preoperative planning for total hip arthroplasty: clinical evaluation.

The purpose of this study is to clinically validate a new two-dimensional preoperative planning software for cementless total hip arthroplasty (THA). Manual and two-dimensional computer-assisted planning were compared by an independent observer for each of the 30 patients with osteoarthritis who underwent THA. This study showed that there were no statistical differences between the results of both preoperative plans in terms of stem size and neck length (<1 size) and hip rotation center position (<5 mm). Two-dimensional computer-assisted preoperative planning provided successful results comparable to those using the manual procedure, thereby allowing the surgeon to simulate various stem designs easily.

Arthroplasty, Replacement, Hip↗
PubMed2004

Post-traumatic overload or acute syndrome of the os trigonum: a possible cause of posterior ankle impingement.

The purpose of this paper is to discuss the post-traumatic overload syndrome of the os trigonum as a possible cause of posterior ankle impingement and hindfoot pain. We have reviewed 19 athletes who were referred to our foot unit between 1995 and 2001 because of posterior ankle pain, and in whom a post-traumatic overload syndrome of os trigonum was diagnosed. All these patients were followed up over a period of 2 years. In 11 cases a chronic repetitive movements in forced plantar flexion was found. In the other eight cases the pain appeared to persist after a standard treatment of an ankle sprain in inversion plantar flexion. The diagnosis was based on clinical history, physical examination and X-rays that revealed a non-fused os trigonum. The confirmation of diagnosis was carried-out injecting local anaesthetic under fluoroscopic control. In all cases a corticosteroid injection as first line treatment was performed. In 6 cases a second injection was necessary to alleviate pain because incomplete recovery with the first injection. Three cases (16%) were recalcitrant to this treatment and in these three cases a surgical excision of the os trigonum was carried out. Our conclusion is that after some chronic athletic activity or an acute ankle sprain the os trigonum, if present, may undergo mechanical overload, remain undisrupted and become painful. Treatment by corticosteroid injection often resolves the problem.

Adult↗
PubMed2003

Sub- or intertrochanteric fracture following screw fixation of an intracapsular proximal femoral fracture: true complication or technical error?

PURPOSE: To review, retrospectively, the possible causes of sub- or intertrochanteric fractures after screw fixation of intracapsular fractures of the proximal femur. METHODS: Eighty-four patients with an intracapsular fracture of proximal femur were operated between 1995 and 1998 by using three cannulated 6.25 mm screws. The screws were inserted in a triangular configuration, one screw in the upper part of the femoral neck and two screws in the inferior part. Between 1999 and 2001, we use two screws proximally and one screw distally. RESULTS: In the first series, two patients died within one week after operation. Sixty-four fractures healed without problems. Four patients developed an atrophic non-union; avascular necrosis of the femoral head was found in 11 patients. Three patients (3.6%) suffered a sub- and/or intertrochanteric fracture after a mean postoperative time of 30 days, in one case without obvious trauma. In all three cases surgical revision was necessary. Between 1999 and 2001 we did not observe any fracture after screwing. CONCLUSION: Two screws in the inferior part of the femoral neck create a stress riser in the subtrochanteric region, potentially inducing a fracture in the weakened bone. For internal fixation for proximal intracapsular femoral fracture only one screw must be inserted in the inferior part of neck.

Adult↗
PubMed2003

[10 years experience in surgical resuscitation at a university hospital center. Determination of a criterion for identifying patients at risk for fatal irreversible coagulopathy].

The authors evaluated ten years of surgical reanimation in the University Centre of Lausanne (CHUV). Irreversible coagulopathy (IC) is the predominant cause of death for the polytraumatized patient. Acidosis, hypothermy, and coagulation troubles are crucial elements of this coagulopathy. The authors looked for a criterion allowing the identification of dying of IC. In a retrospective study, laboratory results of pH, TP, PTT, thrombocyte count and the need for blood transfusion units were checked for each major step of the primary evaluation and treatment of the polytraumatized patients. These results were considered as critical according to criteria of the literature (30). The authors conclude that the apparation of a third critical value may be useful to identify the polytraumatized patient at risk of dying of IC status. This criterion may also guide the trauma team in selecting a damage control surgical approach (DCS). This criterion was then introduced into an algorithm involving the Emergency Department, the operating room and the Intensive Care Unit. This criterion is a new tool to address the patient at the crucial moment to the appropriate hospital structure.

Adolescent↗
PubMed2001

A computer model to simulate patellar biomechanics following total knee replacement: the effects of femoral component alignment.

OBJECTIVE: The objective of this study is to analyze the biomechanics of the patellar component following total knee replacement. More specifically we investigated the effect of displacing the femoral component of an Insall-Burstein II total knee replacement on the patellar tracking and patello-femoral contact pressures. DESIGN: We used a validated computer simulation of the knee joint to virtually insert the femoral component with the following four types of placements: (1) no misplacement, (2) 5 degrees of internal rotation, (3) 5 degrees of external rotation and (4) 5 degrees of flexion rotation. The patellar 3D tracking and patello-femoral contact pressures were computed for each femoral component placement as a function of knee flexion angle. BACKGROUND: Complications at the patello-femoral joint are the among most frequent following total knee replacement. RESULTS: Femoral component placement unevenly affected the associated patellar tracking: a 5 degrees internal rotation tilted and rotated the patella laterally by about 5 degrees throughout knee flexion. A 5 degrees external rotation of the femoral component had less effect on patellar tracking. A rotation of 5 degrees in flexion primarily caused patellar rotation (5-10 degrees lateral rotation). Femoral component malalignment had only minor effects on the peak pressure distributions at the patello-femoral interface. CONCLUSION: These results suggest that femoral component positioning primarily affects patellar tracking, with a possible threat for patellar subluxation under external rotation of the femoral component. RELEVANCE: Precise alignment of the prosthetic components is difficult to control during total knee replacement due to the lack of precise anatomical landmarks in the human knee joint. Consequently, the position of each prosthetic component may differ from the ideal one suggested by the manufacturer. Improper alignment of the prosthetic components during total knee replacement may lead to premature implant failure.

Arthroplasty, Replacement, Knee↗
PubMed2001

[The health professional's approach to chronic lumbago: clinical experience at the Spinal Cord Unit at the orthopedic hospital].

The treatment of back pain patients refers to the biopsychosocial model of care. This model includes illness in patient's personal and relational life. In this context, it is not only the physical symptom of the patient which is focused but also his psychological distress often hidden by algic complain. Clinical interviews conducted with back pain patients have highlighted psychosocial aspects able to influence the relationship between health care user and provider. Taking account of psychosocial aspects implies an interdisciplinary approach that identify and assesses patients' needs through adequate tools. As a result, the different health care providers implied with back pain patients have to collaborate in a structured network.

Chronic Disease↗
PubMed2000

Comparison between standard radiography and spiral CT with 3D reconstruction in the evaluation, classification and management of tibial plateau fractures.

The aim of this study was to compare the diagnostic efficiency of plain film and spiral CT examinations with 3D reconstructions of 42 tibial plateau fractures and to assess the accuracy of these two techniques in the pre-operative surgical plan in 22 cases. Forty-two tibial plateau fractures were examined with plain film (anteroposterior, lateral, two obliques) and spiral CT with surface-shaded-display 3D reconstructions. The Swiss AO-ASIF classification system of bone fracture from Muller was used. In 22 cases the surgical plans and the sequence of reconstruction of the fragments were prospectively determined with both techniques, successively, and then correlated with the surgical reports and post-operative plain film. The fractures were underestimated with plain film in 18 of 42 cases (43%). Due to the spiral CT 3D reconstructions, and precise pre-operative information, the surgical plans based on plain film were modified and adjusted in 13 cases among 22 (59%). Spiral CT 3D reconstructions give a better and more accurate demonstration of the tibial plateau fracture and allows a more precise pre-operative surgical plan.

Adult↗
PubMed2000

[Review of infected total arthroplasties of the hip and knee--apropos of 28 cases].

This study is a long-term analysis of a group of patients with infected arthroplasties of the hip or the knee. We identified 28 patients with an infected arthroplasty (22 hips, 6 knees) documented by bacterial culture or on direct examination. At the time of diagnosis and on follow-up (a mean of 46 months after treatment) we evaluated the clinical picture, the radiological appearances of the articulation and the biological parameters. 19/28 patients showed a typical clinical picture, whereas in 9 others the picture was more doubtful. The treatments were 14 two-stage replacements of the arthroplasties, 7 simple resections, 5 conservative treatments and 2 one-stage replacements. On follow-up, 25 patients were considered as cured of their infection and 3 as failures. From a functional viewpoint, 9 patients showed no limitation, whereas 19 were limited in the daily activity. Half of the patients had no pain. Radiology showed that 20/26 evaluated patients had no signs of recurrence. Paraclinical examinations are important in the diagnosis of persistent low grade infections, particularly the demonstration of bacteria by pre-surgical sampling (fine needle aspiration, culture from draining sinuses). In spite of the cure of infection, the functional and painful sequellae are often considerable. As a result of our experience, we recommend a two-stage surgical procedure. Only when the general condition of the patient is poor, or when the infection is not under control, would we envisage an alternative procedure (arthrodesis, girdelstone, conservative).

Aged↗
PubMed2000

Limb salvage by neoadjuvant isolated perfusion with TNFalpha and melphalan for non-resectable soft tissue sarcoma of the extremities.

AIMS: Patients with non-resectable soft tissue sarcomas of the extremities do not live longer if they are treated by amputation or disarticulation. In order to avoid major amputations, we tested isolated limb perfusion (ILP) with tumour necrosis factor alpha (TNF)+melphalan+/-interferon-gamma (IFN) as a pre-operative, neoadjuvant limb salvage treatment. METHODS: Twenty-two patients were included (six men and 16 women; three upper limb and 19 lower limb tumours). The AJCC stage was IIA in four patients, III in seven and IV in 11. Thirteen cases were recurrent or progressive after previous therapy; five tumours had a diameter >/=20 cm, and four were multiple or regionally metastatic. There were six malignant fibrous histiocytomas, five liposarcomas, four malignant peripheral nerve sheath tumours, three rhabdomyosarcomas, two leiomyosarcomas, one recurrent extraskeletal osteosarcoma and one angiosarcoma. RESULTS: Twenty-four ILPs were performed in the 22 patients, and 18 (82%) experienced an objective response: this was complete in four (18%) and partial in 14 (64%). Three patients had a minimal or no response and the tumour progressed in one case. All patients had fever for 24 hours but only one developed a reversible grade 3 distributive shock syndrome with no sequelae. There was no grade 4 toxicity. Seventeen patients (77%) underwent limb-sparing resection of the tumour remnants after a median time of 3.4 months: 10 resections were intracompartmental and seven extracompartmental. Surgery included flaps or skin grafts in five patients, arterial replacement in two and knee arthrodesis in one. Adjuvant chemotherapy was given to eight patients and radiotherapy to six. In one patient amputation was necessary after a second ILP. Secondary amputations were performed for recurrence in two patients, resulting in an overall limb salvage rate of 19/22 (86%). After a median follow-up of 18.7 months, 10 recurrences were recorded: seven were both local and systemic and three were only local. The median disease free and overall survival times have been >12.5 and 18.7 months respectively: this is similar to the outcome after primary amputations for similar cases. CONCLUSION: ILP with TNF and chemotherapy is an efficient limb sparing neoadjuvant therapy for a priori non-resectable limb soft tissue sarcomas.

Adult↗
PubMed2000

The fixation of the cemented femoral component. Effects of stem stiffness, cement thickness and roughness of the cement-bone surface.

After cemented total hip arthroplasty (THA) there may be failure at either the cement-stem or the cement-bone interface. This results from the occurrence of abnormally high shear and compressive stresses within the cement and excessive relative micromovement. We therefore evaluated micromovement and stress at the cement-bone and cement-stem interfaces for a titanium and a chromium-cobalt stem. The behaviour of both implants was similar and no substantial differences were found in the size and distribution of micromovement on either interface with respect to the stiffness of the stem. Micromovement was minimal with a cement mantle 3 to 4 mm thick but then increased with greater thickness of the cement. Abnormally high micromovement occurred when the cement was thinner than 2 mm and the stem was made of titanium. The relative decrease in surface roughness augmented slipping but decreased debonding at the cement-bone interface. Shear stress at this site did not vary significantly for the different coefficients of cement-bone friction while compressive and hoop stresses within the cement increased slightly.

Alloys↗
PubMed2000

Inability of serial fibrin monomer measurements to predict or exclude deep venous thrombosis in asymptomatic patients undergoing total knee arthroplasty.

Fibrin monomer (FM) is a highly sensitive marker of venous thromboembolism and can be used to rule out deep venous thrombosis (DVT) and/or pulmonary embolism in symptomatic outpatients. The aim of the study was to investigate the usefulness of serial fibrin monomer determinations to predict or rule out DVT after total knee arthroplasty in asymptomatic patients. One hundred and thirty consecutive patients underwent total knee replacement. Blood samples were obtained in 104 of them the day before, at days 1, 3, 6 after surgery and at the day of phlebography. Phlebography was performed in all these patients between days 8 and 12 after surgery. There were 44 DVT (44/104, 42%). As compared with the patients without DVT, FM mean levels were 2 and 1.5 times higher in the DVT group at day 3 (P < 0.001) and day 6 (P < 0.01), respectively. However, no useful cut-off values for DVT prediction or exclusion could be determined due to the scattering of the values. Therefore, despite differences between patients with or without DVT, serial FM determinations are of no value for predicting or ruling out DVT in individual patients undergoing total knee arthroplasty.

Arthroplasty, Replacement, Knee↗
PubMed2000

[Treatment of coxarthrosis with fitted total hip prostheses replacement].

The treatment of hip osteoarthritis with total hip arthroplasty has continuously evolved since it was first introduced in the sixties. The problem of aseptic loosening of the cemented prostheses, mainly in young active patients, has stimulated two different types of research: on one side the improvement of cementing techniques and on the other side the development of cementless osteoinegrable implants. We discuss the problems of these cementless hip prostheses. Recently published anatomic and biomechanic studies have led to the development of personalized custom femoral stems for each patient. The conception technique and first clinical results are described.

Adult↗
PubMed1999

[External radiotherapy or non-steroidal anti-inflammatory drugs for prevention of heterotopic ossification following total hip replacement].

Heterotopic ossification (HO) is detained as the development of abnormal ossification in soft tissues. HO is a common disease after total hip replacement. Many therapeutic modalities have been proposed to prevent HO. The most commonly used modalities are non-steroidal anti-inflammatory drugs (NSAID) or ionizing radiation administered just before or immediately after total hip replacement. As far as external radiation therapy is concerned, there are several published randomized studies aimed at investigating its efficacy and timing related to surgery, and at comparing ionizing irradiation to NSAID. In this article we review the published data in order to define guidelines which could be used in daily practice for the choice of prophylactic treatment against HO.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

INTERMED--an assessment and classification system for case complexity. Results in patients with low back pain.

STUDY DESIGN: Cross-sectional investigation and follow-up of patients with low back pain. OBJECTIVES: To evaluate the capacity of the INTERMED--a biopsychosocial assessment and classification system for case complexity--to identify patients with a chronic, disabling course of low back pain and to predict treatment outcome. SUMMARY OF BACKGROUND DATA: An impressive number of biologic and nonbiologic factors influencing the course of low back pain have been identified. However, the lack of a concise, comprehensive, reliable and validated classification system of this heterogeneous patient population hampers preventive and therapeutic progress. METHODS: The INTERMED was used to assess patients with low back pain, who participated in a functional rehabilitation program (n = 50) and patients with low back pain who applied for disability compensation (n = 50). Patients of the rehabilitation program were observed to assess the effects of treatments. RESULTS: The INTERMED distinguished between patients in different phases of disability and provided meaningful information about the biopsychosocial aspects of low back pain. In hierarchical cluster analysis two distinct clusters emerged that differed in the degree of case complexity and treatment outcomes. CONCLUSIONS: This first application of the INTERMED indicates its potential utility as a classification system for patients with low back pain.

Adult↗
PubMed1999

Temporal feature estimation during walking using miniature accelerometers: an analysis of gait improvement after hip arthroplasty.

A new method for the detection of gait cycle phases using only two miniature accelerometers together with a light, portable digital recorder is proposed. Each subject is asked to walk on a walkway at his/her own preferred speed. Gait analysis was performed using an original method of computing the values of temporal parameters from accelerometer signals. First, to validate the accelerometric method, measurements are taken on a group of healthy subjects. No significant differences are observed between the results thus obtained and those from pressure sensors attached under the foot. Then, measurements using only accelerometers are performed on a group of 12 patients with unilateral hip osteo-arthritis. The gait analysis is carried out just before hip arthroplasty and again, three, six and nine months afterwards. A mean decrease of 88% of asymmetry of stance time and especially a mean decrease of 250% of asymmetry of double support time are observed, nine months after the operation. These results confirm the validity of the proposed method for healthy subjects and its efficiency for functional evaluation of gait improvement after arthroplasty.

Acceleration↗