Carles Amat

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.

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.

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.

Case report: first report of a prosthetic joint infection caused by Facklamia hominis☆ , ☆☆ ,★

Facklamia spp. are gram-positive cocci first described in 1997. They are α-hemolytic, facultative anaerobes, catalase-negative cocci, resembling viridians streptococci on 5% sheep blood agar. Facklamia hominis is, by far, the most common species of the 6 so far described, and it is thought that its natural habitat is the female genital tract. Four previous human infections with Facklamia spp. have been documented. We report the first case of a chronic prosthetic joint infection caused by F. hominis and its successful treatment by a 2-stage exchange procedure to eradicate the infection. This is also the first osteoarticular infection reported. The clinical implications are discussed.

Isolated medial foot compartment syndrome after ankle sprain

Foot compartment syndrome is a serious potential complication of foot crush injury, fractures, surgery, and vascular injury. An acute compartment syndrome isolated to the medial compartment of the foot after suffering an ankle sprain is a rare complication. We report the case of a 31-year-old man who developed a medial foot compartment syndrome after suffering a deltoid ligament rupture at ankle while playing football. The patient underwent a medial compartment fasciotomy with resolution of symptoms. Compartment syndromes of the foot are rare and have been reported to occur after severe trauma. But, there are some reports in the literature of acute exertional compartment syndrome. In our case, the compartment syndrome appeared after an ankle sprain without vascular injuries associated.

Outcome of oscillating saw open osteotomy in two-stage lower extremity bone transport with monolateral frame

INTRODUCTION Bone transport techniques have been widely used to solve massive bone defects due to trauma, osteomyelitis or bone tumors. The technique of bone interruption to achieve better new bone formation is a subject of debate. Low-energy osteotomy (LEO) techniques have been proposed as the gold standard. Some authors reject open osteotomy with an oscillating saw (OOS osteotomy), based on the danger of bone tissue thermal necrosis and periosteal damage. To date, however, there is no strong clinical evidence to discourage this high-energy (HEO) bone interruption technique. METHODS The aim of this study was to determine outcomes in using OOS osteotomy in a series of patients, where monolateral-frame bone transport has been used to resolve segmental bone defects of the lower extremity. The minimum accepted follow-up was 1 year. The primary endpoints were radiographic evidence of regenerated bone quality (Li classification) and final outcome (Cattaneo clinical system assessment). Further, we analyzed associated complications, and compared results with other published series. We hypothesized that OOS osteotomy produces results no less favorable than those achieved with other, low-energy techniques. RESULTS A total of 54 patients, with an average bone defect of 8.58cm (CI95% 7.01-10.16), were enrolled in the study. In terms of regeneration quality, 84% of the regenerated segment shapes were associated with good outcomes; only 16% exhibited a shape (hypotrophic) predictive of a poor outcome. Regarding functional assessment, following the Cattaneo system, we found a total of 90% good or excellent results. Finally, the Bone Healing Index (BHI) in our series averaged 21.09 days per cm. The main complication observed was pin-track infection, occurring in 45% of the cases. CONCLUSION According our data, the superiority of an LEO technique over HEO techniques is yet to be confirmed; it appears that any open osteotomy is effective, performed well and in a proper clinical setting, and that many factors other than choice of osteotomy technique must play important roles.

Necrotising fasciitis of the extremities: implementation of new management technologies

INTRODUCTION Necrotising fasciitis (NF) is potentially life-threatening soft-tissue infection. Early diagnosis and aggressive surgical debridement are critical to decrease mortality and morbidity. The impacts of new management technologies such as hydro-bisturi-assisted debridement (HAD) and negative pressure wound therapy (NPWT) are not yet clear with respect to treatment of NF. The objective of this study was to describe laboratory (including LRINEC score), clinical and microbiological factors, treatment methods and outcomes related to managing necrotising fasciitis, focusing on the implementation of new treatment methods in our centre. METHODS From June 2010 to June 2014, adult patients diagnosed with necrotising fasciitis affecting an upper or lower limb that were admitted to our hospital, a referral tertiary care centre, were eligible to participate in this study. Demographic data, clinical features, location of infection, Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score on the day of admission, microbiology and laboratory results, use of HAD, wound management using NPWT, and patient outcomes were retrospectively analysed. A univariate risk factor analysis was performed, in an attempt to define prognostic factors for mortality. RESULTS A total of 20 patients satisfied the inclusion criteria. Type II NF (Group A ß-haemolytic streptococci) was found in 8 cases (40%). The average LRINEC score on the day of admission was 6. The lower extremity was affected in 60% of the cases. All patients were treated operatively, with 2.5 interventions on average. Hydro-bisturi was used in the first debridement in 40% of the cases (8 out 20). In 75% of the studied cases, Negative Pressure Wound Therapy (NPWT) was the technique selected for surgical wound management. The global mortality rate was 30%. On univariate analysis, the only factors significantly associated with mortality were high levels of creatinin (p=0.033) and low blood glucose levels (p=0.012). Finally, four amputations were observed in this series. CONCLUSION We confirm that necrotising fasciitis (NF) of the extremities, despite new advancements in treatment and critical care management, is still a potentially life-threatening soft-tissue infection (30% mortality). New, advanced wound management modalities have been heavily used in management of necrotising fasciitis, but these have not had significant impacts on morbidity and mortality rates.

Two-stage knee arthrodesis using a cemented modular tumour replacement system for recalcitrant septic proximal tibial non-union: a case report

Knee arthrodesis is an alternative to amputation for treating recalcitrant septic non-union of the proximal tibia with bone loss, soft-tissue compromise, and knee-joint involvement. Nonetheless, arthrodesis is difficult to achieve if bone loss is massive, and the septic environment can result in failed bone fusion. We report on a 77-year-old man with massive bone loss secondary to recalcitrant septic non-union who underwent radical bone resection, followed by knee arthrodesis using a cemented modular intercalary megaprosthesis in conjunction with a microvascularised flap in 2 stages.