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Biomedical subjects

P Hernigou

Publications and source records attributed to P Hernigou.

At least 19 recordsLinked to original sources
PubMed2002

Patellar impingement following unicompartmental arthroplasty.

BACKGROUND: Patellofemoral complications (osteoarthritis and impingement) have been rarely reported after unicompartmental arthroplasty, and their long-term consequences are not known. The purpose of the present study was to analyze these complications following unicondylar arthroplasty. METHODS: We evaluated the results of ninety-nine unicompartmental arthroplasties that had been performed in eighty patients with osteoarthritis of the knee. The medial compartment was replaced in seventy-four knees and the lateral compartment, in twenty-five. All ninety-nine knees were evaluated with regard to patellar impingement and osteoarthritic changes on skyline radiographs after an average duration of follow-up of fourteen years (range, ten to twenty years). In addition, the seventy-seven knees (fifty-eight patients) that had not been revised were evaluated with use of the clinical scoring system of the Knee Society and specific questions regarding patellofemoral symptoms after an average duration of follow-up of fifteen years (range, ten to twenty years). The relationship between patellar complications (osteoarthritis and impingement) and the position of the femoral component was evaluated with use of lateral radiographs of the knee. RESULTS: At the time of the most recent follow-up, twenty-nine knees had osteoarthritic changes in the portion of the patellofemoral joint opposite the compartment with the implant and twenty-eight knees had impingement of the femoral component on the patella. The knees that had impingement did not have osteoarthritic changes. Pain while ascending or descending stairs and pain on rising from a chair were noted more frequently in knees with patellar complications (impingement and osteoarthritis) (p = 0.02), and these symptoms affected the stair-climbing functional score. These symptoms were more severe in knees with patellar impingement than in knees with degenerative changes. One revision was performed because of patellar impingement. Patellar impingement was more frequent after lateral arthroplasty than after medial arthroplasty (p = 0.02) and was associated with placement of the femoral component too far anteriorly (p = 0.001). CONCLUSION: After unicompartmental arthroplasty, the patellofemoral joint was affected by degenerative changes and patellar impingement. These complications appeared to have been mutually exclusive and affected the functional outcome of the arthroplasty. Patellar impingement affected the knee more severely with regard to both symptoms and the need for revision.

Adult↗
PubMed2002

Determining humeral retroversion with computed tomography.

BACKGROUND: The purpose of this study was to develop and standardize a technique in which computed tomography images are used to determine the humeral torsion angle with landmarks that can be used during surgery. METHODS: One hundred and twenty cadaveric humeri were studied. The retroversion of these anatomical specimens was measured on a computed tomography scan and compared with the direct measurements of the specimens. The retroversion of the humerus was measured by determining the orientation of the proximal articular surface of the humerus with respect to the transepicondylar line of the distal part of the humerus and the forearm axis. To evaluate this method of measuring retroversion, the protocol was tested in patients before and after shoulder arthroplasty. RESULTS: The degree of reproducibility of the measurements made on the computed tomography scan was evaluated by determining the interclass correlation coefficient. The interclass correlation coefficient was considered good (between 0.85 and 0.90) for the measurements of the normal humeri when the orientation of the articular surface measured in the distal part of the humeral head, the epicondylar axis, and the ulnar axis were used as references. There was a significant difference (p < 0.01) between the mean angular orientation of the proximal articular surface with respect to the epicondylar axis (17.6 degrees ) and the mean angular orientation of the proximal articular surface with respect to a line perpendicular to the forearm axis (28.8 degrees ). Despite a wide variation in the humeral torsion angle among the specimens from the different cadavera, the angle varied little between the two normal humeri of the same individual (mean side-to-side difference, 2.1 degrees ). CONCLUSION: This study demonstrated that retroversion of the proximal part of the humerus can be reliably measured with computed tomography. CLINICAL RELEVANCE: Determining retroversion with computed tomography is more accurate than palpating the epicondylar axis or using the forearm as a goniometer during surgery. Computed tomography is useful for measuring the amount of rotation of humeri with a malunited fracture or severe arthritic deformity.

Aged↗
PubMed2002

[Leg length changes after upper tibial osteotomy: analysis of different preoperative planning methods].

PURPOSE OF THE STUDY: The amount of change in the length of the lower limb resulting from upper tibial osteotomy depends on the type of osteotomy performed, the preoperative length of the limb, the degree of preoperative deformity and the amount of correction obtained. Wedge resection, for example, removes bone tissue and can lead to shortening. Inversely, a lengthening effect may result from correction of deformity. The purpose of this article was to present an analysis of the differences between different types of osteotomies and compare their effect on leg length. METHODS: Change in length of the lower limb was studied with a mathematical analysis in opening wedge osteotomy, closing wedge osteotomy, and dome osteotomy. Leg length was calculated for several preoperative deformity angles of the entire limb (hip-knee-ankle angle) and several values of planned correction. RESULTS: The theoretical mathematical model demonstrated that the greatest changes in leg length are obtained with opening wedge osteotomy, followed by dome, then closing wedge osteotomy. Tables were established showing calculated change in leg length. Tracings on radiographs or CT scans used to measure these changes are explained. Methods applicable in case of flexion contracture of the knee are presented. DISCUSSION AND CONCLUSION: Once the initial question regarding length changes is posed, many of the points become evident on image tracings. This work points out how quickly tables can be used to recognize significant differences in leg length changes produced by different osteotomies.

Anthropometry↗
PubMed2001

Open wedge tibial osteotomy with acrylic bone cement as bone substitute.

We studied the results of 245 valgus producing high tibial osteotomies performed with the use of an opening wedge technique and rigid internal fixation followed by early passive and active motion of the knee. Previous studies have used iliac bone grafts or hemicollastasis held by an external fixator for opening the osteotomy. In our series the opening was obtained by a block of cement interposed in the postero-medial part of the osteotomy. This series confirms that the opening wedge osteotomy allows good accuracy for the correction. Ninety-three percent of the knees had a correction adjusted between 180 and 187 degrees for the hip-knee-ankle angle. Survivorship analysis showed an expected rate of survival, with conversion to a total knee on the end point, of 94% at 5 years, 85% at 10 years and 68% at 15 years. Conversion to a total knee arthroplasty was accomplished without difficulty in the patients who had this procedure done. We recommend opening wedge tibial osteotomy with acrylic cement bone cement as bone substitute, rigid internal fixation, and early motion for patients who undergo high tibial osteotomy.

Adult↗
PubMed2001

Routine use of adjusted low-dose oral anticoagulants during the first three postoperative months after hip fracture in patients without comorbidity factors.

OBJECTIVE: This study reports the efficacy of adjusted low-dose oral anticoagulants in the prevention of fatal pulmonary embolism after hip fracture. STUDY DESIGN: Consecutive clinical study. PATIENTS: Five hundred patients with hip fracture received oral anticoagulants as exclusive treatment. These patients were considered preoperatively not to have an increased risk for the development of postoperative pulmonary embolism; they had no poorly controlled systemic illness and were followed-up for at least three months. The average age was seventy-four years (range, 65-80). Anticoagulant therapy was begun on the evening of the operation and continued for three months. The dose was adjusted to keep the prothrombin time between seventeen and twenty seconds. Neither phlebography, sonography, nor lung scan was done routinely. RESULTS: Among the 500 patients, 476 continued to take low-dose oral anticoagulant for three months after the operation. Eight pulmonary embolisms were observed, but none was fatal. Only one patient developed a postoperative hematoma requiring surgical reoperation. CONCLUSIONS: In the absence of poorly controlled systemic illness, low-dose oral anticoagulants can be used after hip fracture.

Administration, Oral↗
PubMed2001

Volumetric analysis of osteonecrosis of the femur. Anatomical correlation using MRI.

We tested the accuracy of MRI for the precise quantification of the volume of osteonecrosis in 30 hips (stage III). The values were compared with direct anatomical measurements of the femoral heads obtained after total hip replacement. When the area of osteonecrosis was determined visually, and manually outlined on each slice, the accuracy of the measurement of volume was satisfactory, and the mean absolute deviation between MRI and anatomical measurements was similar to that between two MRI data sets. For ten of the hips which were measured by MRI, both before and after collapse, the volume did not appear to change significantly. Our findings suggest that the volume of osteonecrosis can be determined with accuracy by MRI, both before and after collapse.

Femur Head↗
PubMed2000

Inactivation of HIV by application of heat and radiation: implication in bone banking with irradiated allograft bone.

We developed methods for inactivating the human immunodeficiency virus by heat and ionizing radiation and tested the effects of these treatments on the mechanical strength of bone. Simultaneous use of heat and radiation caused a considerably greater inactivation of HIV than the additive effects of the two separate treatments, but also caused a significant reduction in the maximum load sustained by the bone specimens tested with an Instrom machine. Application of the same doses but given in the sequential fashion of radiation followed by heat also caused marked inactivation of HIV and had less effect on the mechanical strength of the bone.

Biomechanical Phenomena↗
PubMed2000

Bilateral hip osteonecrosis: influence of hip size on outcome.

OBJECTIVE: To measure the volume of osteonecrosis in 30 patients with disease in both hips (one side with collapse and the other without at Ficat stage I). METHOD: The volume of the osteonecrosis was measured by magnetic resonance imaging. RESULTS: The progression to collapse was influenced by the size of the lesion in each patient. The first collapsed hip was that with the largest volume of osteonecrosis. CONCLUSION: The volume of the osteonecrotic lesion on the second hip (stage I without collapse) is a good predictor of the time to collapse of this second hip.

Disease Progression↗
PubMed2000

Proximal entry for intramedullary nailing of the tibia. The risk of unrecognised articular damage.

The risk of articular penetration during tibial nailing is well known, but the incidence of unrecognised damage to joint cartilage has not been described. We have identified this complication in the treatment of tibial fractures, described the anatomical structures at risk and examined the most appropriate site of entry for tibial nailing in relation to the shape of the bone, the design of the nail and the surgical approach. We studied the relationship between the intra-articular structures of the knee and the entry point used for nailing in 54 tibiae from cadavers. The results showed that the safe zone in some bones is smaller than the size of standard reamers and the proximal part of some nails. The structures at risk are the anterior horns of the medial and lateral menisci, the anterior part of the medial and lateral plateaux and the ligamentum transversum. This was confirmed by observations made after nailing 12 pairs of cadaver knees. A retrospective radiological analysis of 30 patients who had undergone tibial nailing identified eight at risk according to the entry point and the size of the nail. Unrecognised articular penetration and damage during surgery were confirmed in four. Although intramedullary nailing has been shown to be a successful method for treating fractures of the tibia, one of the most common problems after bony union is pain in the knee. Unrecognised intra-articular injury of the knee may be one cause of this.

Adult↗
PubMed2000

[Hand on composite prosthesis after resection of peri-acetabular sarcoma].

PURPOSE OF THE STUDY: To improve function after pelvic resection involving theacetabulum we have used an anatomic composite implant built with screws and cement. MATERIAL AND METHOD: Since 1990, 27 patients with peri-acetabular bone sarcoma have been treated by extensive resection followed by "hand on innominate prosthesis with constrained total hip prosthesis. The hand on innominate prosthesis was made of a titanium cup, a set of long titanium screws and 2 or 3 packs of gentamycin loaded ciment. RESULTS: Many postoperative complications were observed; deep infection (15 p. 100), hip prosthesis dislocation (33 p. 100) and local recurrence (17 p. 100). Nine patients (33 p. 100) had to be reoperated. Nevertheless at last follow up 24 patients still had their composite prosthesis. The mean functional result, rated according to a modified Enneking's staging system, was 83 p. 100 with unlimited walking without support, average hip flexion 100 degrees, length discrepancy less than 1 centimeters. DISCUSSION: These results were similar to those described in the literature for custom made innominate prosthesis and much better than those of alternative reconstructive procedures. Hand on composite prosthesis is cheaper, easier, more adaptable and enables better anchorage than custom-made prosthesis. Such a procedure can be used even after total iliac wing resection. CONCLUSIONS: The advantages of such procedure pleads for using it extensively after acetabular resection. But long term follow up is necessary to validate indications.

Acetabulum↗
PubMed1999

Do voids in a femoral cement mantle affect the outcome?

A total of 156 ceramic versus ultra-high-molecular-weight polyethylene hip prostheses were followed for a minimum of 10 years to compare the outcome of the femoral component in 2 groups: those with and those without radiologically detectable voids in the cement mantle. No significant difference was observed. In this series, voids with a 5-mm diameter had no effect on loosening of the femoral component over a 10-year period.

Bone Cements↗
PubMed1999

Interleukin-6 in the blood of patients with total hip arthroplasty without loosening.

Patients with total hip arthroplasty were screened for the presence of proinflammatory cytokines in the systemic circulation. Only increased levels of interleukin-6 were detected in patients having had total hip arthroplasty more than 10 years ago. These increased levels of interleukin-6 were associated with a decrease in bone mineral density associated with polyethylene wear and with radiologic osteolysis in some patients. These abnormalities were not found in control subjects without total hip arthroplasty or in patients who had a prosthesis in place for less than 6 years. The elevation in interleukin-6 levels found in patients with the oldest prostheses could constitute a marker for periprosthetic osteolysis.

Aged↗
PubMed1999

Decrease in the mesenchymal stem-cell pool in the proximal femur in corticosteroid-induced osteonecrosis.

We have evaluated bone-marrow activity in the proximal femur of patients with corticosteroid-induced osteonecrosis and compared it with that of patients with osteonecrosis related to sickle-cell disease and with a control group without osteonecrosis. Bone marrow was obtained by puncture of the femoral head outside the area of necrosis and in the intertrochanteric region. The activity of stromal cells was assessed by culturing fibroblast colony-forming units (FCFUs). We found a decrease in the number of FCFUs outside the area of osteonecrosis in the upper end of the femur of patients with corticosteroid-induced osteonecrosis compared with the other groups. We suggest that glucocorticosteroids may also have an adverse effect on bone by decreasing the number of progenitors. The possible relevance of this finding to osteonecrosis is discussed.

Adolescent↗
PubMed1998

Abnormalities of the adult shoulder due to sickle cell osteonecrosis during childhood.

PATIENTS AND METHODS: A retrospective study of 110 adults with sickle cell anemia (SS genotype) was conducted to determine the frequency of complications of sickle cell osteonecrosis of the shoulder in childhood. The glenohumeral joint was evaluated on plain anteroposterior and lateral radiographs of the shoulder. RESULTS: Mean time since osteonecrosis of the shoulder was 24 years. Radiographic abnormalities were seen in 106 of the 220 shoulders (48.2%). Both shoulders were affected in 86% of cases and at least one hip in 96%. Radiographic abnormalities included isolated caput magna, caput plana, a short humeral neck and ascension of the tuberosities. Twelve shoulders exhibited glenoid fossa abnormalities, which consisted in complete or partial hypoplasia. Evidence of glenohumeral osteoarthritis was seen in 11 shoulders. DISCUSSION: The shoulder abnormalities seen in our patients were probably due to growth disturbances in the proximal humerus secondary to osteonecrosis of the humeral head during childhood. They were common but less likely to produce functional impairment than osteonecrosis-related lesions of the hip. However, some patients had premature osteoarthritis and geometric shoulder abnormalities responsible for functional loss in adulthood.

Adolescent↗