[How to repair a cartilage hole].
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Arthroplasty↗
Biomedical subjects
E Gautier
Publications and source records attributed to E Gautier.
Treatment of proximal humerus fracture using multiple intramedullary flexible nails.
A total of 61 patients with a proximal humeral fracture was treated between January 1996 and March 1998 by closed reduction and fracture fixation with intramedullary Prévot (or Nancy) nails. Of these, 28 female and 25 male patients with a mean age of 52 years (range 3-91 years) were reviewed clinically and radiologically with a mean follow-up of 17 months (range 4-30 months). The mean Constant score was 63, the mean Neer score 74 and the mean visual analogue scale (VAS) 73. The 14 patients under 24 years old achieved a Constant score of 86, a Neer score of 99 and a VAS of 97, while 13 patients aged between 25 and 60 years had a Constant score of 67, a Neer score of 75 and a VAS of 71. The 26 patients older than 61 years had a Constant score of 48, a Neer score of 61 and a VAS of 61. One patient with total and 6 with partial humeral head necrosis as well as 5 pseudarthroses were noted. Proximal nail perforation of the humeral head due to fracture collapse was seen in 22 cases. Complications were more frequently observed in the elderly. End results were not related to the type of fracture. This minimally invasive technique decreases the rate of occurrence of avascular necrosis of the humeral head. However, fractures are not sufficiently stabilised, mainly because of bone loss induced by impaction and osteoporosis. Bone loss remains an unsolved problem, and alternative methods such as the use of bone substitute combined with minimally invasive techniques should be studied.
Activities of Daily Living↗
Effect of plate position relative to bending direction on the rigidity of a plate osteosynthesis. A theoretical analysis.
Mechanical unloading of the plated bone segment is observed after plate osteosynthesis because the implant takes over a part of the physiological loading. Strain reduction in the bony tissue depends on the rigidity of the plate (cross-sectional area, geometrical form, and modulus of elasticity). The aim of the present study was to calculate theoretically the effect of plate position relative to bending direction on the overall bending stiffness of the composite system plate-bone. To calculate the rigidity, a cylindrical bone model with mechanical characteristics similar to a sheep tibia and a rectangular plate cross-section corresponding to a DC-plate with either a modulus of elasticity of steel or titanium was used. Calculations under different bending directions were performed according to the laws of the linear bending theory and the composite beam theory. The bending stiffness of a plate osteosynthesis reaches a minimum and a maximum respectively, in cases in which the bending moment acts in the direction of the main axis of the area moment of inertia of the plate. The minimum is present with the plate bent vertically, the maximum with the plate bent horizontally, e.g. on the tension side of the composite system--on the assumption that the bone structure opposite the plate is capable of withstanding compressive loading. For steel and titanium plates, factors of 2 and 2.25 respectively were calculated between the minimum and the maximum bending stiffnesses of the osteosynthesis. The bending rigidity of the plate alone has only a minimal effect on the total stiffness of the osteosynthesis. With a plate bent vertically, the difference between steel and titanium plates was 18%, with the plate bent horizontally (situated on the tension side), it was only 7%. The bending stiffness of a plate osteosynthesis depends on the cross-section, the geometrical form, and the modulus of elasticity of the plate, as well as on the plate position relative to the bending direction of the composite system. The modulus of elasticity of the plate is relatively unimportant, while with a given plate the individual plate position relative to the bending direction is of crucial importance. Thus, changing the modulus of elasticity of the plate cannot solve the problem of implant induced unloading of the bone cortex because the bending stiffness of the composite system depends much more on the plate position relative to the bending direction.
Animals↗
Strain distribution in plated and unplated sheep tibia an in vivo experiment.
After plate osteosynthesis changes in bone biology and bone mechanics are observed in the plated bone segment. Compromise of the vascular supply in the plate bed leads to a remodelling process and to a temporary porosity in the bone cortex underneath the plate. In addition, the plate takes over some of the physiological loading of the bone, which in turn alters the normal strain distribution of the cortical bone tissue. The aim of the present study is to determine the tissue deformation of the sheep tibia in vivo and the changes in tissue strain due to plating with plates of different rigidities. Measurements were performed on the intact bone at the mid diaphysis using the strain gauge technique. With different connections on the tension bridge (Wheatstone bridge), the strain was measured separately for pure axial loading, bending, and torsion before and after plating with a 4.5 mm stainless steel or titanium DCP. Under physiological load the sheep tibia is mainly deformed in torsion (62%) and bending (33%), and much less in axial loading (5%). Plating with a steel plate reduces the overall tissue strain by 18%, with a titanium plate by 13%. This reduction is mainly due to a reduction in axial tissue strain due to axial loading and bending and less to the reduction of tissue strain under torsion. In our in vivo model, plating with steel or titanium plates leads to a reduction of the physiological tissue strains. The difference between the different plates is small due to the fact that the high tissue strain under torsion is only slightly affected by plating. Thus, from the purely mechanical point of view and with regard to preserving normal tissue strains as much as possible, titanium plates offer little advantage compared with stainless steel plates. But, titanium as an implant material may offer advantages with respect to tissue compatibility and infection resistance.
Animals↗
The Burch-Schneider antiprotrusio cage in acetabular revision surgery: a mean follow-up of 12 years.
A total of 38 acetabular revisions using a Burch-Schneider antiprotrusio cage in 37 patients (18 women and 19 men), with a mean age at surgery of 75 years (range, 55-88 years), were evaluated retrospectively with a mean follow-up of 12 years (range, 8-21 years). In 2 cases with total hip dislocation and in 1 case with a deep infection, revision of the antiprotrusio cages was required. Defining every revision of the antiprotrusio cage as the endpoint of survivorship, the antiprotrusio cage showed a survival rate of 92% after 21 years. Clinical evaluation of the surviving patients showed a mean Harris hip score of 76 points (range, 20-96). Radiologic evaluation revealed that 1 antiprotrusio cage was loose and that 4 femoral stems were loose. The Burch-Schneider antiprotrusio cage compares favorably with other devices with regard to long-term implant survival rate.
Aged↗
The anatomy and function of the gluteus minimus muscle.
In order to investigate the functional anatomy of gluteus minimus we dissected 16 hips in fresh cadavers. The muscle originates from the external aspect of the ilium, between the anterior and inferior gluteal lines, and also at the sciatic notch from the inside of the pelvis where it protects the superior gluteal nerve and artery. It inserts anterosuperiorly into the capsule of the hip and continues to its main insertion on the greater trochanter. Based on these anatomical findings, a model was developed using plastic bones. A study of its mechanics showed that gluteus minimus acts as a flexor, an abductor and an internal or external rotator, depending on the position of the femur and which part of the muscle is active. It follows that one of its functions is to stabilise the head of the femur in the acetabulum by tightening the capsule and applying pressure on the head. Careful preservation or reattachment of the tendon of gluteus minimus during surgery on the hip is strongly recommended.
Aged↗
Anatomy of the medial femoral circumflex artery and its surgical implications.
The primary source for the blood supply of the head of the femur is the deep branch of the medial femoral circumflex artery (MFCA). In posterior approaches to the hip and pelvis the short external rotators are often divided. This can damage the deep branch and interfere with perfusion of the head. We describe the anatomy of the MFCA and its branches based on dissections of 24 cadaver hips after injection of neoprene-latex into the femoral or internal iliac arteries. The course of the deep branch of the MFCA was constant in its extracapsular segment. In all cases there was a trochanteric branch at the proximal border of quadratus femoris spreading on to the lateral aspect of the greater trochanter. This branch marks the level of the tendon of obturator externus, which is crossed posteriorly by the deep branch of the MFCA. As the deep branch travels superiorly, it crosses anterior to the conjoint tendon of gemellus inferior, obturator internus and gemellus superior. It then perforates the joint capsule at the level of gemellus superior. In its intracapsular segment it runs along the posterosuperior aspect of the neck of the femur dividing into two to four subsynovial retinacular vessels. We demonstrated that obturator externus protected the deep branch of the MFCA from being disrupted or stretched during dislocation of the hip in any direction after serial release of all other soft-tissue attachments of the proximal femur, including a complete circumferential capsulotomy. Precise knowledge of the extracapsular anatomy of the MFCA and its surrounding structures will help to avoid iatrogenic avascular necrosis of the head of the femur in reconstructive surgery of the hip and fixation of acetabular fractures through the posterior approach.
Aged↗
Strain gauges used in the mechanical testing of bones. Part I: Theoretical and technical aspects.
The internal restructuring of bone as a reaction to physiological load described by Wolff's law is related to both stress and strain in the bone. Bone is a rather brittle material, with nearly equal properties in tension and in compression: Elastic modulus E = 20 Gpa, tensile strength sigma tens = 200 Mpa (cortical bone). In biomechanics, it is very easy to assess strain using strain gauges. The theoretical and technical aspects specific to the use of strain gauges on bones are presented in this paper including how the measurements are taken and how the data is analyzed.
Biomedical Engineering↗
Strain gauges used in the mechanical testing of bones. Part II: "In vitro" and "in vivo" technique.
How to choose and prepare the strain gauges for bonding on bones "in vitro" and "in vivo"? This communication aims to elucidate technical details and some applications: direct assessment of the axial load, the bending moment, and the torque applied to long bones by the physiological loads. As a typical example of application, we will show the assessment of stress protection due to plates on the bones in the sheep tibia.
Animals↗
Strain gauges used in the mechanical testing of bones. Part III: Strain analysis, graphic determination of the neutral axis.
The problem addressed in this part is the analysis of the strain pattern within the bone, when the strain has been measured using strain gauges along the long axis of the diaphysis of a bone subjected to axial load, bending, or eccentric axial load. It is first necessary to obtain the position of the strain gauges using, for instance, computed tomography. The linear bending theory is then used to determine graphically the position of the neutral axis in a cross section and the strain field within the bone. An example of application is taken from the literature: Rybicky et al. (1) measured the reduction of strain within a plated horse metatarsus, relative to that of the intact bone. They made an analytical strain analysis. A comparison is made between the analytical results and the graphic ones, validating the graphic method.
Biomedical Engineering↗
Fixation of high tibial osteotomy with the AO cannulated knee plate.
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Adult↗
Growth disturbances after injuries of the proximal tibial epiphysis.
Proximal tibial epiphyseal fractures are very rare. Partial growth arrest of the physis can cause important axial malalignment in the frontal or the sagittal plane or both, with subsequent shift of the weight-bearing axis onto the injured compartment of the knee joint. To detect the exact extent of the deformity, comparative radiographs of the contralateral side in two planes using long films as well as standing whole leg orthoradiographs are desirable. Accurate measurements in our series of six patients revealed deformities in two, which required secondary surgical correction.
Adolescent↗
The evolution of femoral shaft plating technique.
There has been an evolution in the AO/Association for the Study of Internal Fixation plating technique during the past 3 decades that includes the use of longer plates and fewer plate screws, fewer lag screws outside the plate, fewer unicortical screws at the plate periphery, and greater use of the 95 degrees blade plate to achieve balanced fixation of proximal and distal shaft fractures. These changes reflect an evolving technique of plate osteosynthesis that emphasizes indirect reduction techniques, biologic internal fixation, and improved biomechanics. Outcome data suggest that there has been an improvement with time that is reflected by shorter time to union, a decrease in the frequency of implant failures, delayed unions, nonunions, malunions, number of reoperations, and in overall rate of failure. The best predictor of success was the length of plate by logistic regression analysis. With the evolution of plating techniques and a greater emphasis on biology of fracture healing, the incidence of complications and failures has decreased after femoral shaft plating. Plate osteosynthesis of the femoral shaft is particularly advantageous in many situations and can be quite successful (87% success rate in Group III).
Adolescent↗
Trochanteric flip osteotomy for cranial extension and muscle protection in acetabular fracture fixation using a Kocher-Langenbeck approach.
OBJECTIVE: To describe the advantages and surgical technique of a trochanteric flip osteotomy in combination with a Kocher-Langenbeck approach for the treatment of selected acetabular fractures. DESIGN: Consecutive series, teaching hospital. METHODS: Through mobilization of the vastus lateralis muscle, a slice of the greater trochanter with the attached gluteus medius muscle can be flipped anteriorly. The gluteus minimus muscle can then be easily mobilized, giving free access to the posterosuperior and superior acetabular wall area. Damage to the abductor muscles by vigorous retraction can be avoided, potentially resulting in less ectopic ossification. Ten consecutive cases of acetabular fractures treated with this approach are reported. In eight cases, an anatomic reduction was achieved; in the remaining two cases with severe comminution, the reduction was within one to three millimeters. The trochanteric fragment was fixed with two 3.5-millimeter cortical screws. RESULTS: All osteotomies healed in anatomic position within six to eight weeks postoperatively. Abductor strength was symmetric in eight patients and mildly reduced in two patients. Heterotopic ossification was limited to Brooker classes 1 and 2 without functional impairment at an average follow-up of twenty months. No femoral head necrosis was observed. CONCLUSION: This technique allows better visualization, more accurate reduction, and easier fixation of cranial acetabular fragments. Cranial migration of the greater trochanter after fixation with two screws is unlikely to occur because of the distal pull of the vastus lateralis muscle, balancing the cranial pull of the gluteus medius muscle.
Acetabulum↗
[Complex knee trauma--cartilage injuries].
Traumatic cartilage defects of the knee joint occur in an isolated way due to contusions or due to shear forces as a combined injury with ligamentous damage. They must be documented according to localisation, surface involved and depth. In the adult, only the fragment extending into subchondral bone can be refixed. Purely cartilagineous lesions heal spontaneously under partial repair with fibrocartilage; this can equally be surgically stimulated through surgical drillholes or impaction fractures with awls and pins. Since fibrocartilage is known to be mechanically insufficient and is often not resulting in sufficient sports- and working capacity newer methods and are getting more and more popular enabling the induction and production of hyaline or hyaline-like cartilage. Osteochondral transplantation from the own knee as plugs forming a mosaic has the advantage of being readily available for limited surface size. Repair to a hyaline-like cartilage using a chondrocyte suspension is also possible, and is used for bigger surfaces or defects, it needs however two operations. In the long term it will become the method of choice for defects over 4 cm2.
Adult↗
Phase I trial of recombinant adenovirus gene transfer in lung cancer. Longitudinal study of the immune responses to transgene and viral products.
Animal studies indicate that the use of replication-deficient adenovirus for human gene therapy is limited by host antivector immune responses that result in transient recombinant protein expression and blocking of gene transfer when rechallenged. Therefore, we have examined immune responses to an adenoviral vector and to the beta-galactosidase protein in four patients with lung cancer given a single intratumor injection of 10(9) plaque-forming units of recombinant adenovirus. The beta-galactosidase protein was expressed in day-8 tumor biopsies from all patients at variable levels. Recombinant virus DNA was detected by PCR in day-30 and day-60 tumor biopsies from all patients except patient 1. A high level of neutralizing antiadenovirus antibodies was detected in patient 1 before Ad-beta-gal injection whereas it was low (patient 3) or undetectable in the other two patients. All patients developed potent CD4 type 1 helper T cell (Th1) responses to adenoviral particles which increased gradually over time after injection. Antiadenovirus cytotoxic T lymphocyte responses were consistently boosted in the two patients examined (patients 3 and 4). Sustained production of anti-beta-galactosidase IgG was observed in all patients except patient 1. Consistent with anti-beta-gal antibody production, all patients except patient 1 developed intense, dose-dependent Th1 responses to soluble beta-galactosidase which increased over time. Strong beta-galactosidase-specific cytotoxic T lymphocyte responses were detected in patients 2, 3, and 4. Our results clearly show that despite the intensity of antiadenovirus responses, transgene protein expression was sufficient to induce strong and prolonged immunity in three patients. Recombinant adenovirus injected directly into the tumor is a highly efficient vector for immunizing patients against the transgene protein.
Adenoviridae↗
Parvovirus B19 associated neutropenia. Treatment with Rh G-CSF.
In a 39-year-old patient under follow-up for metastatic adenocarcinoma of the colon, a post-operative fever and a profound neutropenia occurred during hospitalization. A diagnosis of primary infection with parvovirus B-19 was made in view of the association of reticulocytopenia, together with anti-B19 IgM antibodies and positive serum results for viral DNA. The granulocytic lineage appeared to be normal on bone-marrow smears, and anti PMN autoantibodies were not found. Rh G-CSF therapy resulted in a sharp increase in the PMN count. Although the pathophysiology of B19-associated neutropenia remains unclear, Rh G-CSF seems to be effective in this disorder.
Adenocarcinoma↗
Value of cytomegalovirus detection by PCR in bronchoalveolar lavage routinely performed in asymptomatic bone marrow recipients.
In order to compare PCR with rapid virus culture for the early detection of CMV in bronchoalveolar lavage (BAL) after bone marrow transplantation, 26 asymptomatic patients were routinely evaluated for the presence of CMV on day 35 using these two techniques. Concurrent blood samples were also analyzed in all cases. CMV was detected synchronously by both culture and PCR in six of 26 (23%) BAL and in five of 26 (19%) blood specimens. Among these positive specimens, three BAL and blood samples were positive in the same patients. Five (19%) BAL and five (19%) blood samples were culture-negative but PCR-positive. No BAL or blood specimens were positive by culture alone. When considering matched BAL-blood samples, five were positive in only one fluid, BAL (n = 3) or blood (n = 2) using culture, while seven were positive in only one fluid, BAL (n = 4) or blood (in = 3) using PCR. Overall, six of 26 (23%) patients had culture-negative but PCR-positive results. Three of these six patients were positive only in BAL and two of them subsequently received antiviral therapy for development of symptoms suggestive of CMV infection. We suggest that asymptomatic patients with negative-culture but PCR-positive results on day 35 in BAL should be subsequently closely monitored for the presence of CMV.
Adult↗