Long-term outcomes of uncemented or cemented arthroplasty revision following metal-on-metal total hip replacement

Background Which device(uncemented or cemented total hip replacement[UTR or CTR]) is more conducive to the revision of metal-on-metal total hip replacement(MoM-TR) is inconclusive. The purpose of this study was to assess the long-term outcomes of individuals who had undertaken UTR versus CTR following initial MoM-TR. Methods Two hundred and thirty-four individuals(234 hips) had received UTR or CTR following initial MoM-TR during 2007-2018 were reviewed . Outcomes reported in this analysis involving Harris Hip Scores(HHS) as well as the major orthopaedic complications(MOC) were gathered 3 months, 6 months, 12 months, and then every one year after revision. Results From the 12th month after revision to final follow-up, CTR yielded superior HHS than UTR. The MOC rates were 47.4% and 16.1% in the UTR and CTR groups, respectively. Between-group noteworthy divergences were noted regarding the rates of re-revision, prosthesis loosening, and periprosthetic fracture(10.3% for UTR vs 2.5% for CTR, p =0.015; 16.3% for UTR vs 5.9% for CTR, p = 0.011; and 12.0% for UTR vs 4.2% for CTR, p =0.045, respectively). Conclusion The superiority of CTR over UTR in terms of improving HHS and decreasing the MOC rate.

Fungal Periprosthetic Infection after Total Knee Arthroplasty (Case Report and Review)

The rate of periprosthetic infection (PJI) following primary total knee arthroplasty ranges from 0,5 to 6%, while after the revision arthroplasty PJI rate grows up to 13,6%. Despite the fact that PJI is more often caused by gram-positive microorganisms, the treatment of patients induced by gram-negative pathogens and fungi is the most complex and associated with the higher recurrence rate. This paper presents a positive two-stage treatment of a patient with fungal periprosthetic infection with a review of current medical literature. Revision, sanation of infection site and implantation of articulating antibacterial spacer was performed in the first stage of treatment. The second stage, which was the implantation of a revision prosthesis, followed in 6 months after removal of infection nidus. Subsequently the authors obtained good functional outcomes and stopping the infection process.

Reliability of intra-operative frozen section study in revision of infected hip arthroplasty

Introduction Frozen sections are extensively used to help in the diagnosis of periprosthetic joint infection during revision hip arthroplasty, though there are insufficient data in relation to its usefulness. Methods Twenty-one patients with infected hip arthroplasties were operated in the form of one or two-staged revision hip arthroplasties. A frozen section was obtained intra-operatively and > 5 PMN’s/ HPF was considered as a positive indicator of infection. If the frozen section was reported negative (≤5 PMN’s/HPF), the revision prosthesis was implanted after a thorough debridement and a wash. If the frozen section was reported as positive, post the debridement; a non-articulating antibiotic-loaded cement spacer was implanted for 8 weeks, supplemented with 3 weeks of intravenous antibiotics and 3 weeks of oral antibiotics. This was followed by an antibiotic-free interval of 2 weeks. The patient was taken up for a revision surgery once the frozen section study was negative (≤5 PMN’s/HPF). The patients were followed up for a minimum of 1 year to a maximum of 2 years after the revision for any evidence of infection (assessed clinically, serologically, and radiologically). Results Frozen section analysis of PMNs per high power field had a 100% specificity in our patients in detecting periprosthetic joint infection. Conclusion Frozen section study is a safe, rapid, cheap and reliable intra-operative modality to diagnose periprosthetic joint infection.

Microbiological Epidemiology Depending on Time to Occurrence of Prosthetic Joint Infection (PJI): Impact on the Empirical Antimicrobial Strategies

Background Empirical antimicrobial therapy of prosthetic-joint infection (PJI) is a major clinical challenge and current guidelines recommend the combination of vancomycin plus a broad-spectrum β-lactamin. As Gram-negative bacilli (GNB) are probably less represented in late infections, we evaluate the microbiological epidemiology in patients with PJI according to the chronology of infection. Methods All patients managed in a reference center for complex bone and joint infections in France (2011 and 2016) were included in a prospective cohort study. Microbiological data at the time of diagnosis were collected and analyzed according to the chronology of infection. Results We included 567 PJI (284 males, 50.1%; median age 70.3 years). The median occurrence time was 23.4 weeks after prosthesis implantation (285 hip and 255 knee PJI, which were revision prosthesis in 216 [40.3%] cases). Microbiological bone samples found 164 [28.9%] S. aureus (including 26 [16.3%] MRSA), 162 [28.6%] coagulase-negative Staphylococci (CoNS, including 80 [58.8%] methicillin-resistant CoNS), 80 (14.1%) Enterobacteriaceae, 74 (13.1%) Streptococci, and 85 (15.0%) anaerobes (including 60 [10.6%] Propionibacterium). Infection was plurimicrobial in 10 [18.2%] cases. Among the 183 patients (32%) with late PJI (occurring >1 year), obtained after exclusion of the 59 patients (10.4%) with hematogenous origins, Enterobacteriacecae 
(n = 8; 4.4%; P < 10–3) were much less represented than in patients with early PJI occurring <1 year. No difference was observed regarding the the presence of non-fermenting GNB, with a prevalence of 4.6 and 2.7% in early and late PJI, respectively. Taken together, these data suggest that a broad-spectrum β-lactam antibiotic might be useful in only 12 (6.6%) patients with late PJI, compared with 66 (20.3%) patients with early PJI (P < 10–3). Of note, there were statistically more anaerobes (n = 40; 21.9%) in late PJI, including 32 Propionibacterium (17.5%; P < 10–3). Conclusion Considering the minority amount of GNB in late post-operative PJI and the overrepresentation of anaerobes including P. acnes, the empirical treatment should be reconsidered, especially when a two-stage exchange is planned. In those situations, another acceptable option could be the vancomycin+clindamycin combination. Disclosures T. Ferry, HERAEUS: Consultant, Speaker honorarium. S. Lustig, Heraeus: Consultant, Consulting fee.

Fracture of the Modular Neck in Total Hip Arthroplasty

Modularity of the components in total hip arthroplasty has had an increase in popularity in the last decades. We present the case of a 53-year-old man with a history of avascular necrosis of the femoral head due to a hypophyseal adenoma. A total hip modular arthroplasty was implanted. Three and a half years after the surgery the patient attended the emergency room due to acute left hip pain with no prior traumatism. Radiological examination confirmed a fracture of the modular neck. A revision surgery was performed finding an important pseudotumoral well-organized periprosthetic tissue reaction. Through an extended trochanteric osteotomy the femoral component was removed, and a straight-stem revision prosthesis implanted. There are several potential advantages when using modularity in total hip arthroplasty that surgeons may benefit from, but complications have arisen and must be addressed. Various circumstances such as large femoral head with a long varus neck, corrosion, patient’s BMI, and activity level may participate in creating the necessary environment for fatigue failure of the implant.

Revision of a Fractured Uncemented Revision Stem Using a Custom Designed Punch and Retrograde Through-Knee Approach

We report a unique case of a fractured modular cobalt chromium connection taper Revitan (Zimmer, Warsaw, IN) revision prosthesis. Macroscopic examination revealed a fracture at the diaphyseal-metaphyseal junction of this modular component. This report highlights that fractures can still occur with modern modular prostheses. We are not aware of any published failures of the Revitan revision prosthesis. We also describe a unique method of retrieval for a broken well fixed uncemented femoral stem, using a custom designed extraction instrument via a through-knee approach.

Nontraumatic Fracture of the Femoral Condylar Prosthesis in a Total Knee Arthroplasty Leading to Mechanical Failure

This paper reports a case of fatigue fracture of the femoral component in a cruciate-retaining cemented total knee arthroplasty (TKA). A 64-year-old man had undergone a primary TKA for osteoarthritis 10 years previously at another institution using the PFC-Sigma prosthesis. The patient recovered fully and was back to his regular activities. He presented with a history of sudden onset pain and locking of the left knee since the preceding three months. There was no history of trauma, and the patient was mobilizing with difficulty using crutches. Radiographs revealed fracture of the posterior condyle of the femoral prosthesis. Revision surgery was performed as an elective procedure revealing the broken prosthesis. The TC3RP-PFC revision prosthesis was used with a medial parapatellar approach. The patient recovered fully without any squeal. Mechanical failure of the knee arthroplasty prosthesis is rare, and nontraumatic fracture of the femoral metallic component has not been reported before.