[Variables influencing bleeding during total hip arthroplasty]. / Variables influençant le saignement lors d'une arthroplastie totale de hanche.

PURPOSE OF THE STUDY: The purpose of this retrospective analysis was to study the parameters having an effect on blood loss during or after total hip arthroplasty. We examined a series of 350 procedures for primary degenerative hip disease with a normal course (n = 100), rapidly destructive degenerative disease (n = 100), and secondary joint degeneration due to atraumatic osteonecrosis of the femoral head (n = 100) or rheumatoid disease (n = 50). MATERIAL AND METHODS: All arthroplasties were performed via the transtrochanteric approach using Charnley-Kerboull implants. The volume of blood loss was calculated by noting compensated blood loss (transfusion during the procedure and shortly thereafter), and estimated non-compensated loss using the Nadler and Mercuriali and Inghilleri formula. We examined the influence of age, gender, obesity, and surgeon experience. Data were analyzed with the Student-Fisher reduced deviation method was used for quantitative and qualitative variables and the coefficient of correlation for quantitative variables. RESULTS: Blood loss, calculated in ml packed red blood cells (hematocrit 100%), was 573 ml for arthroplasties with a normal course, 713 for arthroplasties secondary to osteonecrosis of the femoral head, and 950 ml for rapidly destructive degenerative disease and finally 609 ml for patients with rheumatoid arthritis. Considering 35% as normal for hematocrit, total estimated blood loss was 1,640, 2,040, 2,710, and 1,740 ml respectively in the different groups. Compared with the group of patients who had a normal course, total blood loss was significantly higher when arthroplasty was performed for osteonecrosis and rapidly destructive degenerative disease (p < 0.001). Age, obesity, and duration of the intervention had no effect on blood loss. Female gender and operator experience had a favorable influence in the group of patients who underwent hip surgery for primary degenerative disease. Blood loss occurring during or shortly after total hip arthroplasty was greater in men, when the procedure was performed for osteonecrosis, and most importantly for rapidly destructive diseases. DISCUSSION: In clinical practice, the influence of gender is not significant enough to require specific preoperative transfusion plans. Conversely, certain etiologies of the joint disease impose transfusion in all such patients, using a blood volume which usually exceeds the possibilities of auto-transfusions.

[Overgrowth of femoral fractures in childhood]. / L'excès de croissance dans les fractures du fémur chez l'enfant.

PURPOSE: The purpose of this work was to define the role of different factors which can accelerate overgrowth of femoral fractures in childhood. MATERIAL AND METHODS: Fifty-one fractures of the femur observed in 28 boys and 23 girls, mean age four years, were treated orthopedically. Twelve fractures involved the upper third of the femur, 34 the middle third and five the lower third. There were 30 transverse, 13 oblique, and eight spiral fractures. Overgrowth (OG) was assessed on x-rays obtained two years after bone healing and defined as the sum of the initial shortening (RI) plus leg length difference (LLD): OG=RI + LLD. RESULTS: OG was 11.3 mm in boys and 7.55 in girls, mean 9.5 mm. OG was greatest between the ages of 3 and 7 years. OG was 18.62 mm in spiral fractures, 9.15 mm in oblique fractures and 7.59 mm in transverse fractures. OG was 12.41, 9.46, and 2.49 mm for the upper, middle, and lower femur. Mean OG was 5.46, 9.43, and 18.09 mm for RI<5 mm, 5 mm 10 mm respectively. There was a linear relationship between RI and OG: OG=0.84 RI + 3.4. DISCUSSION: Taking into account different factors, bony overgrowth can be estimated from the initial shortening in fractures of the femur in children. It is tolerated better in boys, between the age of 3 and 7 years, and for proximal and spiral fractures.

[Outcome after total hip arthroplasty performed for rapidly progressive hip destruction]. / Résultat des arthroplasties totales de hanche réalisées pour coxarthrose destructrice rapide.

PURPOSE OF THE STUDY: Rapidly progressive destruction of the hip joint occurs in approximately 5 to 10% of patients with degenerative hip disease. The cause and natural history remain unclear, but total hip arthroplasty is almost always necessary. We performed a retrospective analysis to determine the particular clinical and radiological features of this condition and to assess long-term outcome after total hip arthroplasty. MATERIAL AND METHODS: One hundred total hip arthroplasties were performed between 1984 and 1988 in patients with rapidly progressive hip destruction (67 women and 11 men, mean age 71 years). The transtorchanteric approach was used in all cases to implant cemented Charnley-Kerboull prostheses. Mean follow-up was 7 years 10 months. RESULTS: There were seven complications: two nonunions of the trochanter, three extensive periprosthetic ossifications, one case of recurrent dislocation, and one late hematogenous infection. At last follow-up, the Merle d'Aubigné classification showed an excellent or very good functional result in 95 hips. Stable fixation was observed for 94 acetabular implants and 97 femoral implants. Six acetabular implants showed signs of loosening: certain=1, probable=4, potential=1. Three femoral implants showed signs of loosening: certain=1, potential=2. All the femoral loosenings were associated with acetabular loosening. Four hips required revision surgery: one for nonunion of the trochanter, one for septic loosening, two for aseptic loosening. DISCUSSION: This series confirmed the radiological and clinical definitions of rapidly progressive hip destruction and demonstrated the reliability of pathological examination of the femoral head and joint capsule. Among the different hypotheses put forward to explain this condition, neither overloading nor use of antiinflammatory drugs would appear to be operating in this series. We were unable to confirm or infirm the micro-crystalline or vascular origin of this condition. Nevertheless, the vascular phenomena observed in the femoral head could be compared with those observed in ischemic joint disease. Arthroplasty led to major blood loss (2706 ml, hematocrit 35). This appears to be higher than observed for arthroplasty performed with the same technique in patients with the usual form of degenerative hip disease. Excepting this fact, the complications observed and the clinical results as well as the longevity of these implants suggest that arthroplasties performed for rapidly degenerative hips are not substantially different from those performed for common degenerative hip disease.

Blood loss in total hip arthroplasty for rapidly destructive coxarthrosis.

We studied the perioperative blood loss in 100 total hip arthroplasties performed for rapidly destructive coxarthrosis and compared it with the blood loss in 100 total hip arthroplasties for regular coxarthrosis. The treatment protocol was identical in both groups. Total blood loss was calculated as the compensated blood loss (volume transfused during and immediately after surgery) and the non-compensated blood loss using Nadler and Mercuriali formula. The mean blood loss calculated in milliliters of red blood cells (100% haematocrit) was 578 ml in regular coxarthrosis and 945 ml in rapidly destructive coxarthrosis. The blood loss after total hip arthroplasty is greater when surgery is performed for rapidly destructive coxarthrosis than for regular coxarthrosis (P < 0.001).

Dynamic light scattering from lyotropic lamellar phases subjected to a flow field.

Dynamic light scattering experiments on lyotropic lamellar phases of brine and surfactant subjected to a flow field have been realized. The obtained results reveal that the relaxation times measured depend strongly on the velocity of the flow. This dependence is indicative of an increase of the effective elasticity modulus K and a decrease of the effective compressibility modulus (-)B of the lamellar phase with the flow velocity. This leads to the conclusion that the shear can induce a suppression of the undulation fluctuations of the bilayers of the lamellar phase. Our results show also that the rigidity of the membranes decreases as the salt concentration of the sample increases.

Shear-induced first-order sponge-to-lamellar transition in a lyotropic surfactant system.

We report a shear-induced sponge (L3) to lamellar (L(alpha)) transition in a surfactant system. Under a constant shear rate, after a delay time t(n) we observe random nucleation and subsequent growth of the L(alpha) phase, demonstrating that the shear-induced transition is first order. A simple argument for the energy of a two-dimensional nucleus accounts for the observed delay and its shear-rate dependence.

Observations of the collapse of dilute lyotropic lamellar phases under shear flow

Experimental evidence of the collapse of dilute lamellar phases due to shear flow is presented. Two systems are used: one composed of brine and an ionic surfactant, and another composed of water, a nonionic surfactant, and cosurfactant. We observe this transition for a range of lamellar spacings and brine salinity. The results are in reasonable agreement with recent theory in which the suppression of fluctuations by shear plays an important role.

Coupling between flow and structure for a lamellar surfactant phase

The flow-structure relation of lamellar phases is studied using rheometry and cross-polarized microscopy under flow. The equilibrium phases show different defects. Low salinities lead to very viscous, "onion" phases, whereas at high salinity, a low viscosity plane lamellar phase is found. Under shear, the latter shows a sudden transition to a viscoelastic gel, with a texture and viscosity very similar to that of the onions. Gelation occurs after a certain delay time, increasing rapidly with salinity, by the nucleation of onions. This allows one to relate the delay time to the defect energy.

[Recurrent multifocal chronic osteomyelitis: scintigraphy or MRI. Apropos of 2 cases]. / Ostéomyélite chronique multifocale récurrente: scintigraphie ou IRM. A propos de deux cas.

We report two cases of chronic recurrent multifocal osteomyelitis. In both cases, MRI demonstrated the presence of asymptomatic lesions that the technetium bone scan failed to show. The asymptomatic lesions were located in the acetabelum and the distal femur. Despite the actual literature, MRI was more specific than bone scan in these two cases.