Pablo S. Corona

Antibiotic Susceptibility in Gram-Positive Chronic Joint Arthroplasty Infections: Increased Aminoglycoside Resistance Rate in Patients With Prior Aminoglycoside-Impregnated Cement Spacer Use

Two-stage revision using aminoglycoside-cement spacers (A-CSs) is widely used to manage chronic periprosthetic joint infection (PJI). However, aminoglycoside-resistance in gram-positive cocci (GPC) seems to be increasing. Moreover, the contribution of these A-CSs to select resistant mutants is a matter of concern. We study the antibiotic susceptibility profile of GPC after 113 chronic hip and knee PJIs. Aminoglycoside susceptibility-profiles were compared between cases where A-CSs had previously been used (n: 52), and cases of primary infection (n: 61). 32% of isolates were resistant to gentamicin and 40.6% to tobramycin. Gentamicin resistance after previous A-CS use was significantly higher (49.2% [30/61] vs. 19.3% [16/83]; P: 0.0001) as well as with tobramycin (52.7% [29/55] vs. 30.9% [21/66]; P: 0.014). A high rate of gentamicin-tobramycin resistance exists among the most common bacteria involved in chronic-PJI. The risk of selection for aminoglycoside-resistant mutants in cases of infection relapse is a concern following A-CS use.

Percutaneous interface biopsy in dry-aspiration cases of chronic periprosthetic joint infections: A technique for preoperative isolation of the infecting organism

PurposePreoperative identification of the infecting micro-organism is of paramount importance in the treatment protocol for chronic periprosthetic joint infections, as it enables selection of the most appropriate antibiotic treatment. Preoperative joint aspiration, the most commonly used sampling technique, has proven to have a broad range of sensitivity values and the frequency of dry aspirations has not been well assessed. In such dry-tap cases a biopsy sample could be an option. The purpose of this study was to assess the diagnostic accuracy of percutaneous interface biopsy (PIB) in isolating the infecting organism in cases of chronic Periprosthetic Joint Infection (PJI) and dry-tap event. The basic technique is to harvest and culture a sample from the periprosthetic interface membrane by a percutaneous technique in the preoperative period.MethodsA retrospective study was done involving 24 consecutive patients suspected of PJI and where no fluid was obtained from the joint. Culture results from a percutaneous interface biopsy (PIB) were compared with intraoperative tissue cultures at the time of revision surgery. In all cases, a two-stage replacement was done.ResultsThe sensitivity was 88.2%; specificity was 100%. Positive predictive value was 100%, while negative predictive value was 77.9%. Accuracy was 91.6%. No technique-related complication was observed.ConclusionWe conclude that PIB is a useful test for preoperative isolation of the infecting organism and could play a role in cases with dry-tap joint aspirations.

Industrially Prefabricated Cement Spacers: Do Vancomycin- and Gentamicin-impregnated Spacers Offer Any Advantage?

BackgroundIndustrially preformed antibiotic-loaded cement spacers are useful to facilitate the second stage of two-stage exchange arthroplasty for infected THAs and TKAs. However, whether gentamicin alone or a combination of antibiotics (such as vancomycin and gentamicin) is more effective is not known.Questions/purposesWe therefore sought to compare industrially prefabricated spacers containing either gentamicin or gentamicin and vancomycin with respect to (1) infection control, (2) complications, and (3) quality of life, pain, and patient satisfaction.MethodsWe performed a review of 51 patients with chronic infections treated at one center using either gentamicin or vancomycin and gentamicin-prefabricated spacers. The former were used exclusively from January 2006 until May 2009, and the latter from June 2009 until July 2011, and there was no overlap. We collected data on demographics, immunologic status (McPherson classification), prosthetic joint infection location, type of prosthesis, microbiologic results, and time between stages. We evaluated the primary outcome of infection control or recurrence after at least 12 months followup. We also recorded complications. Each patient completed a quality-of-life survey, VAS, and a self-administered satisfaction scale.ResultsThe overall infection control rate was 83% after a mean followup of 35 months (range, 12.4–64.7 months). There were no differences between gentamicin and vancomycin and gentamicin spacers in terms of infection eradication (80 % versus 85 %, respectively; p = 0.73), nor in terms of complications, quality of life, pain, or satisfaction scores.ConclusionsPrefabricated, antibiotic-loaded cement spacers has been proven effective for infection control in TKAs and THAs but with the numbers available, we did not find any differences between a gentamicin or vancomycin and gentamicin-prefabricated spacer, and therefore, we are unable to validate the superiority of the combination of vancomycin and gentamicin over gentamicin alone. Because of the higher costs involved with vancomycin and gentamicin spacers, and the potential risks of unselective use of vancomycin, further comparative studies are necessary to evaluate their role in the treatment of infected THAs or TKAs.Level of EvidenceLevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Irrigation and Debridement

Delegates: Craig A. Aboltins, MD, Olivier Borens, MD, John J. Callaghan, MD, Pedro Ivo de Carvalho, MD, Yuhan Chang, MD, Pablo Corona, MD, Ferdinando Da Rin, MD, Silvano Esposito, MD, Thomas K. Fehring, MD, Xavier Flores Sanchez, MD, Gwo-Chin Lee, MD, J. Carlo Martinez-Pastor, MD, S.M. Javad Mortazavi, MD, Nicolas O. Noiseux, MD, Kuo-Ti Peng, MD, Harold Delano Schutte, MD, Daniel Schweitzer, MD, Rihard Trebse, MD, Eleftherios Tsiridis, MD, Leo Whiteside, MD

COMPOSITE VASCULARIZED FIBULAR EPIPHYSEO-OSTEO-PERIOSTEAL TRANSFER FOR HIP RECONSTRUCTION AFTER PROXIMAL FEMORAL TUMORAL RESECTION IN A 4-YEAR-OLD CHILD

Literature on the reconstruction of the proximal femur in skeletally immature patients with the use of an epiphyseal transplant is scarce and with variable results depending on the indication. We report successful outcomes using a modified vascularized fibular epiphyseal transplant in a 4‐year‐old boy with an oncologic lesion. We discuss the advantages of supplementing the standard graft with a vascularized fibular periosteal tissue.

An update on surgical and antimicrobial therapy for acute periprosthetic joint infection: new challenges for the present and the future.

Periprosthetic joint infection (PJI) is a devastating complication that can occur following any arthroplasty procedure. Approximately half of these infections develop within the first year after arthroplasty, mainly in the first 1 to 3 months. These infections are known as early PJI. It is widely accepted that many early PJIs can be successfully managed by debridement, irrigation, and prosthetic retention, followed by a course of biofilm-effective antibiotics (debridement, antibiotics, implant retention procedure), but candidate patients should meet the requirements set down in Zimmerli’s algorithm. The best antibiotic regimen for acute PJI treated without implant removal remains uncertain. Rifampin-containing regimens, when feasible, are recommended in gram-positive infections, and fluoroquinolones in gram-negative cases. The duration, dosage, and administration route of antibiotics and the use of combined therapy are matters that requires further clarification, as the current level of evidence is low and most recommendations are based on experimental data, studies in small series, and expert experience.

Outcome after Knee Arthrodesis for Failed Septic Total Knee Replacement Using a Monolateral External Fixator

Purpose. To evaluate the pain level and patient satisfaction as well as the fusion and infection eradication rates after knee arthrodesis using a monolateral external fixator for failed septic total knee replacement (TKR). Methods. Records of 10 male and 11 female consecutive patients aged 70 to 88 (mean, 81) years who underwent knee arthrodesis using a monolateral external fixator for failed septic TKR were retrospectively reviewed. Each patient had undergone a mean of 3.4 (range, 1–15) procedures. The infection eradication rate, fusion rate, time to achieve fusion, pain level, patient satisfaction, and health-related quality of life were evaluated. Results. Infection was eradicated in 18 (86%) of the 21 patients, whereas fusion was achieved in 17 (81%) of the 21 patients after a mean of 10.3 (range, 4–16) months. Those who did and did not achieve fusion differed significantly in terms of the mean pain score (2.3 vs. 6.4, p=0.031). Compared with age-matched Spanish general population, patients aged >75 years fared significantly worse in terms of the mean physical summary component score (40.7 vs. 34.9, p=0.001). Among those who achieved fusion, 82% were very or somewhat satisfied; none was very dissatisfied. Among those who did not achieve fusion, 75% were very or somewhat dissatisfied. Conclusion. Knee arthrodesis using a monolateral external fixator for failed septic TKR achieved high fusion and infection eradication rates, despite the extended time needed. When fusion is achieved, patients had good pain relief and satisfaction.

Mid-Term Outcomes and Complications with Cementless Distal Locking Hip Revision Stem with Hydroxyapatite Coating for Proximal Bone Defects and Fractures

We revised the first 100 revision total hip arthroplasties using a cementless distal locking revision stem conducted in our referral centre. Average follow-up was 9.2 years (range: 5.5-12 years). Harris Hip Score improved from 42.5 to 81.6, and none had thigh pain at last follow-up. No significant stress shielding, osteolysis, or radiologic loosening was found. All patients showed radiological evidence of secondary implant osseointegration. Overall survival was 97% with three patients being revised: two stem ruptures and one subsidence. We could trace these complications to technical errors. These findings suggest that a diaphyseal fixation of the revision stem with distal locking can provide the needed primary axial and rotational stability of the prosthesis. This would allow further bony ingrowth, enhanced by the hydroxyapatite coating.

Irrigation and debridement.

Liaison: Carl Haasper MD, PhD, MSc Leaders: Martin Buttaro MD (International), William Hozack MD (US) Delegates: Craig A Aboltins MD, Olivier Borens MD, JJ Callaghan MD, Pedro Ivo de Carvalho MD, Yuhan Chang MD, Pablo Corona MD, Ferdinando Da Rin MD, Silvano Esposito MD, Thomas K Fehring MD, Xavier Flores Sanchez MD, Gwo-Chin Lee MD, JC Martinez-Pastor MD, SM Javad Mortazavi MD, Nicolas O Noiseux MD, Kuo-Ti Peng MD, Harold Delano Schutte MD, Daniel Schweitzer MD, Rihard Treb se MD, Eleftherios Tsiridis MD, Leo Whiteside MD

Increased infection risk after hip hemiarthroplasty in institutionalized patients with proximal femur fracture

In patients undergoing hip hemiarthroplasty (HHA) secondary to proximal femur fracture, acute periprosthetic joint infection (PJI) is one of the most important complications. We have detected an increased risk of PJI in chronic institutionalized patients (CIPs), and a higher number of early postoperative infections are caused by Gram-negative bacteria (GNB), not covered by the current prophylaxis (cefazolin in noninstitutionalized patients (NIPs) and cotrimoxazole in CIPs). We sought to compare infection characteristics between NIPs and CIPs, analyzing predisposing factors, causative pathogens, and antibiotic prophylaxis-related microbiological characteristics. We performed a retrospective review of our prospective institutional database to identify all patients consecutively admitted for HHA to treat proximal femur fracture at our centre between 2011 and 2013. PJI was diagnosed in 21 of 381 (5.51%) patients, with 10 of 105 (9.52%) in the CIP group and 11 of 276 (3.99%) in the NIP group, and statistical significance was achieved. GNB accounted for PJI in 14 (66.67%) patients. We detected a single case of methicillin-resistant Staphylococcus aureus (MRSA) infection in the NIP group. We confirm a higher risk of acute PJI among institutionalized patients, commonly caused by Gram-negative microorganisms, which are not covered by the current prophylaxis. New prophylactic strategies should be investigated in order to reduce this problem.