Potential changes to French recommendations about peri-prosthetic infections based on the international consensus meeting (ICMPJI)

AbstractBackgroundDespite the large volume of studies on the prevention, diagnosis, and treatment of peri-prosthetic infections, surgical practice often rests on limited scientific evidence in this field. The vast International Consensus Meeting on Peri-prosthetic Joint Infection (ICMPJI) held in 2013 produced robust recommendations.HypothesisFrench consensus conference recommendations show no major differences with ICMPJI recommendations.Materials and methodsThe 207 recommendations developed by 300 experts at the ICMPJI were translated, and the translation was then examined by four reviewers, including 2 having participated in the consensus conference. The reviewers looked for any differences with French practices and recommendations.ResultsTwenty-three major differences or innovations were identified compared to French recommendations and standard practice. Among them, pre-operative screening for nasal or urinary micro-organisms is performed routinely in France but should be reserved according to the ICMPJI for symptomatic patients and/or patients at high risk for infection. The ICMPJI emphasizes the role for the operating room environment as a vector for infection; more specifically, the operating lamp handle and suction cannula deserve close attention. A wound discharge persisting longer than 5–7 days requires irrigation and debridement. This procedure is effective only within the first 3 post-operative months and/or the first 3 weeks after symptom onset and must include exchange of all modular implants. The ICMPJI warns against both irrigation-debridement in fungal infections (suggesting two-stage prosthesis replacement) and one-stage replacement in patients with sinus tracts. The use of spacers (articulating at the knee) is recommended in the event of two-stage prosthesis replacement.DiscussionThe ICMPJI recommendations differed in many ways with French recommendations and standard practice. They can be expected to impact practices in France, although a point worth noting is that only 1 of the 207 recommendations received unanimous agreement by the conference experts (keeping operating room traffic to a minimum)

The effect of vancomycin and tobramycin on the tensile properties of cured low viscosity bone cements

Samples of plain and vancomycin-tobramycin-loaded low viscosity cements were evaluated for their tensile mech. properties. Vancomycin is effective against nearly all resistant pathogens now involved in prosthesis infection. The mech. properties of vancomycin-impregnated cement have never been studied. Tobramycin extends the spectrum to Gram neg. bacteria and has been well studied as used in bone cement. This antibiotic mixt. covers most of the pathogens resulting from arthroplasty thus providing an active local prophylaxis against infection. Specimens of 4 low-viscosity bone cements were machined, radiographed and tested. The addn. of 2 g vancomycin in 40 g cement powder did not significantly affect the tensile properties of the four cements. Simultaneous addn. of vancomycin (2 g) and tobramycin (1 g) significantly decreased the tensile strength and fracture strain of one cement, but the abs. values remained equal to the others or higher and well above the levels reported with std. viscosity cements. Vancomycin-tobramycin fulfill the criteria required for diffusion and antimicrobial activity after admixing in bone cement. The effects of such a combination on the tensile properties of 4 low viscosity bone cements are acceptable. [on SciFinder (R)

Vancomycin impregnated bone cement: mechanical properties in vitro and in vivo release characteristics

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Minimum 10-Year Outcome of One-Stage Total Hip Arthroplasty Without Subtrochanteric Osteotomy Using a Cementless Custom Stem for Crowe III and IV Hip Dislocation.

Options for total hip arthroplasty (THA) in high dislocated hips include subtrochanteric osteotomy (STO), high hip center positioning, and 2-stage surgery with progressive lowering using an external fixator before THA. We described the long-term results of 1-stage THA performed without STO, using a cementless customized stem associated if necessary with sequential tenotomies and/or greater trochanteric osteotomy. Ninety-eight consecutive THA without STO were performed using this technique. Of those 98 hips, 26 hips with high dislocation (12 class III and 14 class IV according to the Crowe classification) were evaluated at an average follow-up of 16 (10-22) years. At the time of last follow-up, the mean Harris Hip Score was 86 points (37-100). The mean leg-length discrepancy was 7 ± 5 mm (0-17). Two transient (7.7%) nerve palsies (1 sciatic and 1 femoral) were notified. A revision was required for 6 hips (23.1%). Kaplan-Meier survivorship analysis at 15 years regarding aseptic loosening of the femoral component was 87.5% (95% confidence interval, 76.5-99.1). During the same period, acetabular implant survivorship free from revision for aseptic loosening was 96.1% (95% confidence interval, 92.7-99.9). The combination of intramedullary fit and extramedullary adaptation for offset and anteversion provided by the custom stem can avoid additional procedures associated to THA in high developmental dysplasia of the hip. The clinical function and long-term survival reported in this series is encouraging for THA performed in case of high hip dislocation

Three-dimensional morphology of the proximal femur.

In the field of uncemented hip arthroplasties, secondary biologic fixation of femoral implants depends directly on the quality of the primary stability. Metaphyseal filling and a good fit between the implant and the proximal femur improve initial stabilization and optimize the transmission of forces to the bone. Precise knowledge of the three-dimensional femoral shape is essential to the design and selection of adapted implants. Three hundred ten femurs in 300 patients suffering from primary hip osteoarthritis were analyzed by computed tomography scanning. After three-dimensional reconstruction, several measurements were extracted, and the parameters essential to the characterization of the diverse femoral morphologies encountered were identified. A new classification of the proximal femur is proposed. The consequences on the design and the preoperative selection of femoral implants are discussed

Three-dimensional computed cementless custom femoral stems in young patients: midterm followup.

We prospectively evaluated the results of our custom cementless femoral stems to ascertain whether this technology produced reasonable clinical function, complication rates, and loosening rates at midterm. Fifty-seven consecutive patients had surgery in 62 hips for primary osteoarthritis at a mean age of 57 years using a three-dimensional computed custom cementless stem. Patients were reviewed at a mean followup of 94.9 months. At review, the mean Harris hip score was 98.8 points (range, 84-100) compared with 61.1 (range, 28-78) points preoperatively. No patient complained of thigh pain. No migration or subsidence was observed. All stems were considered stable according to the radiographic criteria defined by Engh et al. There were no dislocations, no infections, and no reoperations. Our results are comparable with published results from clinical and radiologic points of view. Two problems remain unsolved: the price of a custom stem is twice as expensive as a standard stem; and we need longer term results before definitely recommending this technology as a reasonable alternative to current arthroplasties in younger patients. The data support the continued exploration of this technology with controlled clinical followup. LEVEL OF EVIDENCE: Therapeutic study, Level II-1 (prospective cohort study). See the Guidelines to Authors for a complete description of levels of evidence

Étude de la formation de débris d'usure dans la prothèse totale de hanche par un modèle numérique particulaire

La présence de débris d'usure de polyéthylène à haut poids moléculaire (UHMWPE) est une des causes principales du descellement des prothèses totales de hanche. Les travaux expérimentaux de Cooper ont montré de multiples détériorations microscopiques de la surface de la cupule dues à de l'usure par abrasion et adhésion. Les mécanismes de l'usure abrasive sont liés à différents paramètres tels que la charge normale et la vitesse de glissement appliquées mais également de l'angle d'attaque des particules d'usure ou des aspérités microscopiques. Le but de la présente étude est d'analyser l'effet de la géométrie d'une aspérité sur les mécanismes d'abrasion de la surface de la cupule en UHMWPE ainsi que la formation de particules d'usure. Il s'agit de simuler une aspérité rigide glissant sur la surface de la cupule en polyéthylène en utilisant la méthode numérique particulaire appelée « Smoothed Particle Hydrodynamics » (SPH)

The torsion of the proximal femur in cementless total hip arthroplasty: a 3-dimensional evaluation.

The anatomy of the proximal femur at the time of total hip arthroplasty has been widely studied but the horizontal plane was never considered, or only limited to the torsion of the femoral neck. Using CT-scan images from a group of 178 patients scheduled for cementless total hip arthroplasty (THA), we analysed the evolution of the torsion of the proximal femoral metaphysis, in reference to the posterior bicondylar plane of the femur. The evolution of the torsion, between 20 mm below the centre of the lesser trochanter and 20 mm above, was evaluated. In cases of primary osteoarthritis, osteonecrosis, rheumatoid arthritis and epiphysiolysis capitis femoris, the mean torsion decreased from 46° to 20° without significant differences in average values between the different diagnoses, but important individual variations were found. In the groups of dysplasia and congenital hip dislocation, the torsion values were significantly higher, decreasing in mean from 59° to 25° and 63° to 34° respectively, and with important individual variations. These data are important when using cementless femoral stems, since an ideal fit-and-fill in the proximal femur zone has been shown to positively influence bone ingrowth of the stem. However, a strict adaptation of the stem to the medullary canal, without considering its torsion, can lead to an increased or decreased torsion of the prosthesis neck and thus to an instability of the arthroplasty. For these reasons, if a perfect adaptation of the stem to the intramedullary anatomy and an optimal reconstruction of the extramedullary anatomy are to be achieved, 3-dimensional planning should ideally be obtained for every patient. This will allow the best stem choice adapted to every single patient and every kind of anatomy