Alain Lortat-Jacob

Diagnosis of prosthetic joint infection by beadmill processing of a periprosthetic specimen

We report a microbiological process for the documentation of prosthetic joint infection (PJI). Intraoperative periprosthetic tissue samples from 92 consecutive patients undergoing revision surgery for PJI were submitted to mechanized beadmill processing: specimens were aseptically collected in polypropylene vials, filled with sterile water and glass beads and submitted to mechanized agitation with a beadmill. The documentation rate of PJI following culture on solid and liquid media was 83.7% and the contamination rate 8.7%. Final documentation was obtained after overnight culture for 51.9% of cases and with 7 days of broth culture for all documented cases.

Influence of posterior condylar offset on knee flexion after cruciate-sacrificing mobile-bearing total knee replacement: a prospective analysis of 410 consecutive cases.

The range of motion of the knee joint after Total Knee Replacement (TKR) is a factor of great importance that determines the postoperative function of patients. Much enthusiasm has been recently directed towards the posterior condylar offset with some authors reporting increasing postoperative knee flexion with increasing posterior condylar offset and others who did not report any significant association. Patients undergoing primary total knee replacement were included in a prospective multicentre study and the effect of the posterior condylar offset on the postoperative knee flexion was assessed after adjusting for known influential factors. All knees were implanted by three senior orthopedist surgeons with the same cemented cruciate-sacrificing mobile-bearing implant and with identical surgical technique. Clinical data, active knee flexion and posterior condylar offset were recorded preoperatively and postoperatively at a minimal one year follow-up for all patients. Univariate and multivariate linear models were fitted to select independent predictors of the postoperative knee flexion. Four hundred and ten consecutive total knee replacements (379 patients) were included in the study. The mean preoperative knee flexion was 112°. The mean condylar offset was 28.3mm preoperatively and 29.4mm postoperatively. The mean postoperative knee flexion was 108°. No correlation was found between the posterior condylar offset or the tibial slope and the postoperative knee flexion. The most significant predictive factor for postoperative flexion after posterior-stabilized TKR without PCL retention was the preoperative range of flexion, with a linear effect.

Decreased Susceptibility to Teicoplanin and Vancomycin in Coagulase-Negative Staphylococci Isolated from Orthopedic-Device-Associated Infections

ABSTRACT We studied 315 coagulase-negative Staphylococcus strains recovered prospectively during 240 surgical procedures (206 subjects) from proven or suspected device-associated bone and joint infections. Sixteen strains (5.1%) had decreased susceptibility to glycopeptides: 15 (12 S. epidermidis strains, 2 S. capitis strains, and 1 S. haemolyticus strain) to teicoplanin alone (MIC of 16 mg/liter, n = 9; MIC of 32 mg/liter, n = 6) and one (S. epidermidis) to both teicoplanin and vancomycin (MIC, 16 and 8 mg/liter, respectively). Decreased susceptibility to teicoplanin was more prevalent in “infecting” strains (i.e., strains recovered from ≥2 distinct intraoperative samples) than in “contaminants” (i.e., strains not fulfilling this criterion) (8.1% [12/149] versus 2.4% [4/166], respectively [P = 0.022]). One hundred percent (13/13) of S. epidermidis strains with decreased susceptibility to teicoplanin were resistant to methicillin (versus 112/173 [64.7%] for S. epidermidis strains susceptible to teicoplanin; P = 0.021).

Résultats des changements de prothèse de genou pour infection: À propos de 107 cas

Resume Le but de cette etude etait d’evaluer les resultats des changements de protheses de genou pour infection, tant sur la guerison de l’infection que sur l’aspect fonctionnel. II s’agit d’une etude retrospective multicentrique portant sur 107 cas d’infections sur prothese totale de genou (PTG). Soixante-dix-sept patients ont eu un changement de PTG en deux temps et 30 ont eu un changement en un temps. Le recul minimum a ete de 2 ans et le recul moyen de suivi a ete de 52 mois. La guerison de l’infection a ete obtenue deux fois sur trois apres changement en un ou deux temps. A deux ans de recul, 77 % des patients sans aucun facteur de risque etaient gueris, contre 65 % des patients presentant un seul facteur de risque et 33 % des patients cumulant au moins deux facteurs de risque d’infection. Sur le plan du resultat fonctionnel et de la mobilite, nous n’avons pas retrouve de difference significative entre le changement en un temps et en deux temps (score KS pour la fonction : 62,5 pour les deux populations, score KS pour le genou : 75,5 lors de changement de PTG en un temps et 74,8 en cas de changement en deux temps (NS)). L’utilisation du fixateur externe entre les deux temps a aggrave le resultat fonctionnel final de facon significative par rapport a l’utilisation d’un espaceur. L’utilisation d’un espaceur articule n’a pas fourni de benefices sur le resultat fonctionnel par rapport a l’espaceur monobloc.PURPOSE OF THE STUDY The purpose of this study was to assess the results of reimplantations of total knee arthroplasties complicated by infection. Outcome was assessed in terms of eradicated infection and function. MATERIAL AND METHODS This retrospective multicentric study included 107 cases of infected total knee arthroplasties treated by changing the implants. Seventy-seven patients had a two-stage revision and thirty had a one-stage procedure. Patients were reviewed with a minimal 2-year and an average 52-month follow-up. RESULTS Revision arthroplasty (one- or two-stage) eradicated infection in two out of three patients. With a two-year follow-up, revision arthroplasty was successful in 77% of patients without any sepsis risk factor, in 65% of patients with one risk factor and in 33% of patients with at least two risk factors. After reimplantation for total knee arthroplasty infection, overall function outcome was good (KS knee score: 74.8 after two-stage revision and 75.5 after one-stage revision, NS). After two-stage procedures, the knee outcome was excellent in one-third of patients, good in another third and fair or poor in the final third. After one-stage reimplantation, 40% of the knees had an excellent outcome, 30% a good outcome and 30% a fair or poor outcome. Regarding functional outcome, overall results were fair (KS function score 62.5 for one-stage and two-stage revisions). Functional outcome was fair or poor in 42% of patients with a two-stage procedure and in 55% of patients with a one-stage revision (NS). DISCUSSION Our study was unable to disclose any difference between one-stage and two-stage revision for eradicating infection. Unfavorable systemic and local conditions decreased the rate of success after revision total knee arthroplasty for infection. Length of infection before reimplantation, number of surgical procedures and bacterial virulence or resistance were not, in our series, predicting factors for failure of septic revision total knee arthroplasty. No difference was found for the clinical and functional results between one-stage and two-stage procedures. Functional outcome was fair or poor for half of the patients after septic revision total knee arthroplsty. The use of an external device between the two procedures for two-stage revision significantly decreased the functional outcome compared with the use of a spacer. Articulated spacers did not offered any advantage compared with a static spacer for functional outcome.

Original portals for arthroscopic decompression of the suprascapular nerve: An anatomic study

Operative treatment of suprascapular nerve entrapment consists of decompression of the nerve, either at the suprascapular notch or the spinoglenoid notch. The aim of this study was to describe new arthroscopic portals to approach these 2 notches at the same time. Twenty shoulders in 10 fresh frozen cadavers were investigated. Four portals were used in line with the scapular spine (S1, S2, S3, S4). The suprascapular pedicle was visualized passing under the supraspinatus muscle. The technique was performed for each specimen. The efficacy and safety of the technique were assessed by open dissection. No injury to the nerve was identified after performing the technique. Decompression was complete in 18 of 20 cases at the suprascapular notch and in all cases at the spinoglenoid notch. With this technique, arthroscopic decompression of the nerve at the suprascapular and spinoglenoid notches is anatomically possible.

Prosthetic Hip Infection Caused by Tropheryma whipplei

ABSTRACT We report a case of prosthetic hip infection due to Tropheryma whipplei in a 74-year-old man not previously known to have Whipples disease. Diagnosis was based on systematic 16S rRNA gene amplification and sequencing of samples obtained during revision hip arthroplasty.

Genetic Analysis of Glycopeptide-Resistant Staphylococcus epidermidis Strains from Bone and Joint Infections

ABSTRACT Glycopeptide-resistant Staphylococcus epidermidis (GRSE) strains are of increasing concern in bone and joint infections (BJIs). Using multilocus sequence typing and multilocus variable-number tandem repeat analysis, we show that BJI-associated GRSE strains are genetically diverse but arise from related, multiresistant hospital sequence types (STs), mostly ST2, ST5, and ST23.

Infection osseuse sur os continu au niveau du membre inférieur: À propos de 127 cas

PURPOSE OF THE STUDY Infection on continuous bone is a specific diagnostic and therapeutic entity. Treatment requires debridement of infected and necrotic soft tissue and bone, dead space management, effective antibiotic therapy in the bone and good skin coverage with well-vascularized tissues. Results of treatment of infection on continuous bone of the lower limb are presented in this series. MATERIAL AND METHODS This retrospective series included 127 cases of osteomyelitis affecting continuous bone of the lower limb (tibia or femur). Septic nonunion and infected arthroplasties were excluded. All patients underwent surgery. The therapeutic protocol was based on debridement, filling of the osteomyelitic cavity as needed (flap, bone grafting, foreign material) and skin cover (by direct closure or flap). Antibiotics were given systematically. Patients were reviewed at minimum two years follow-up. RESULTS Osteomyelitis was located on the tibia in 66% and was posttraumatic in 75% of cases. Localized osteomyelitis (type III of the Cierny-Mader anatomic classification) was found in 50% of patients. Staphylococcus aureus was the causal agent in 66% of cases. Flaps were performed in more than half of cases and most of them were local flaps. Systematic antibiotic therapy was given for an average three months. With an average four years follow-up, eradication of the infection was obtained in 80% of patients. Ten patients were lost to follow-up. No statistical difference was noted for final outcome according to the physiological hoste class, the anatomic localization (tibia or femur), bacteriological findings, duration of antibiotics, use of flaps, or filling of the osteomyelitic cavity. Treatment of type I and II osteomyelitis was more successful than type III or IV infection (NS). Failure rate increased with the number of previous surgical procedures (p=0.02). DISCUSSION Infection on continuous bone is a characteristic entity, rarely clearly separated from other bone infections in reported series that combine these infection with septic nonunions and infected arthroplasties. Surgery is essential and is based on quality debridement. The use of flaps (for both dead space management and skin coverage) improves the results for the treatment of such infections but long-term follow-up is needed for a more accurate assessment of success rate.

289 Inhibition de l’adhérence bactérienne sur le ciment

Introduction Plusieurs strategies existent ou sont en cours d’etude pour la prevention des infections de protheses articulaires. L’impregnation d’antibiotiques sur les surfaces des implants et du ciment a ete proposee, mais plus recemment l’adjonction de polymeres bioactifs modifiant les capacites d’adherence bacterienne semble une solution interessante. L’etude de l’inhibition de l’adherence bacterienne sur le ciment avec polymeres est presentee ici. Materiel et Methode Il s’agit d’une etude in vitro realisee a partir d’echantillons de ciment a base de polymethacrylate de methyle (PMMA). La souche bacterienne utilisee est un Staphylococcus aureus resistant a la Methicilline. Du polymere bioactif porteur de groupements sulfonates a ete ajoute au polymere de PMMA a differentes concentrations. Pour chaque concentration de polymere, des mesures d’adherence bacterienne ont ete realisees sur les echantillons de PMMA avec une concentration identique d’albumine et de fibrinogene et apres une culture overnight d’une suspension de Staphylococcus aureus. Lors de chaque manipulation, des echantillons « temoins » avec du PMMA sans polymere etaient egalement testes pour pouvoir comparer les modifications d’adherence du Staphylococcus aureus au ciment. Le nombre d’unites formant colonies (ufc) presentes sur les echantillons de ciment etait ensuite calcule et rapporte au nombre d’ufc incubees. Resultats Pour les differentes concentrations de polymere ajoute au PMMA, l’adherence du Staphylococcus aureus sur la surface des echantillons de ciment etait plus faible en presence de polymere. La concentration la plus faible de polymere permettant une diminution de l’adherence bacterienne a ete recherchee. Discussion L’inhibition de l’adherence bacterienne par la modification de la surface des implants ou du ciment semble une voie interessante dans la lutte contre les infections sur protheses. Des tests biomecaniques sont cependant necessaires pour verifier l’absence de modification du comportement mecanique du ciment. Conclusion L’adjonction de polymeres bioactifs au ciment permet d’observer une diminution de l’adherence bacterienne in vitro. D’autres etudes in vitro et in vivo sont en cours.

Treatment of an Infected Joint Prosthesis: Difficult Challenge for an Orthopedist Surgeon

To manage an infected arthroplasty remains a challenge for the physician both for the diagnosis and for the treatment. For the infectious disease physician, the main problem is to assess with accuracy the present infection according to the history of the patient, to clinical and biological data, and to look for distant infectious foci. Moreover, he has to control the efficacy and tolerance of the antibiotic therapy. For the microbiologist, the challenge is to identify with accuracy the infecting agents and to make the difference within contamination and real infection. For the anesthesiologist, the problem is to analyze the general conditions of the patient before surgery in order to know which type of surgery and anesthesia would be optimal for the patient. For the orthopedist surgeon, the difficulty is not only to know if the implant has to be removed in a one or two-stage protocol, but the challenge is to be able to have a perfect cleaning of bone and soft tissues in order to control the infection and to make a perfect reconstruction in order to achieve good functional results.