Biofilm Growth on Orthopaedic Cerclage Materials: Nonmetallic Polymers Are Less Resistant to Methicillin-Resistant Staphylococcus Aureus Bacterial Adhesion.

BACKGROUND: Data on bacterial adhesion to cerclage cables are sparse. We aimed to compare 5 cerclage products for methicillin-resistant Staphylococcus aureus (MRSA) adhesion to determine the claim: Are nonmetallic polymer cables more resistant to bacterial adhesion than common metallic wires and cables? METHODS: The following 5 cerclage products were compared: (1) monofilament stainless steel (SS) wires; (2) multifilament SS cables; (3) multifilament cobalt chrome cables; (4) multifilament Vitallium alloy (cobalt-chrome-molybdenum [Co-Cr-Mo]) cables; and (5) multifilament nonmetallic polymer cables. Each was cut into 2 cm lengths and placed into 12-well plates. Of the wells, 5 were wire or cables in trypticase soy broth with MRSA, with the remaining wells being appropriate controls incubated for 24 hours at 37° C and 5% CO2 with shaking. Wires and cables were prepared and randomly imaged via scanning electron microscopy, with bacterial counts performed on 3 images of 3 different wires or cables per study group. The scanning electron microscopy technician and counting investigator were blinded. Additionally, SS wire and polymer cables were analyzed by microcalorimetry for metabolic activity and bacterial load. RESULTS: Bacterial attachment differed significantly between study groups in the middle section (P = .0003). Post hoc comparison showed no difference between groups individually (all P > .05) apart from polymer cables (median 551 bacteria) having significantly increased attached bacteria compared to the Vitallium alloy cable (157, P = .0004), SS cable (101, P = .0004), and SS wire (211, P = .0004). There was no difference between polymer and cobalt chrome cables (133, P = .056). Microcalorimetry supported these results, as polymer cables had a shorter time to max heat flow (6.2 versus 7.5 hours, P = .006), increased max heat flow (117 versus 64 uW, P = .045), and increased colony-forming units, indicating an increased bacterial load compared to SS wires. CONCLUSIONS: This in vitro study demonstrated that polymer cables have increased MRSA adhesion compared to common metallic wires and cables. Future studies are necessary to confirm the translation of increased bacterial adherence on polymer cables to increased rates of orthopaedic infections.

Bridging Massive Acetabular Defects With the Triflange Cup: 10- to 28-Year Results.

BACKGROUND: Massive acetabular bone loss, encountered complex primary or revision total hip arthroplasty, remains a reconstructive challenge. The custom triflange cup reliably achieves both early fixation and longer-term stability. This study presents the 10-year minimum three-surgeon follow-up of acetabular defects managed with a custom triflange component. METHODS: All patients who underwent a custom triflange acetabular component implantation from January 1992 to December 2009 were identified. Demographics, implant data, outcomes, and reoperations were collected and analyzed. Bone defects in all cases were Paprosky type IIIA, IIIB, or IV. A total of 233 patients (241 hips) underwent implantation of a custom triflange during the study period. There were 81 patients (83 hips) who died prior to minimum follow-up and 84 patients (88 hips) had minimum follow-up of 10 years (mean 15.2; range, 10 to 28), or failure prior to 10 years. RESULTS: Complications requiring additional surgery occurred in 43 hips (49%). There were 10 revisions for failure (11.4%); four were due to recurrent infection, three for aseptic loosening, and one for recurrent infection with all revised to a new triflange. There was one patient who was resected to a Girdlestone for infection and one patient was revised for infection to a bipolar hemiprosthesis due to a healed discontinuity. CONCLUSION: To our knowledge, this study represents the largest cohort and longest follow-up in the current literature and demonstrates excellent survivorship and clinical results at an average of 15 years follow-up. The component was retained in 89% of cases.

The Value of Serological Screening Prior to Conversion Total Hip Arthroplasty.

BACKGROUND: This study sought (1) to assess the value of serological testing prior to conversion total hip arthroplasty (THA) in predicting infection and (2) to identify optimal serological values for routine diagnostic workup prior to conversion THA. METHODS: All patients at our tertiary referral center undergoing conversion THA after hip/acetabular fracture procedure from 2013 to 2018 were retrospectively reviewed. Inclusion criteria were patients previously undergoing hemiarthroplasty or open reduction and internal fixation of acetabular, intertrochanteric, and subtrochanteric fractures that progressed to conversion THA due to post-traumatic arthritis having erythrocyte sedimentation rate/C-reactive protein (CRP) prior to conversion. Infection was defined as positive intraoperative cultures not deemed contaminant in collaboration with infectious disease consult and/or development of PJI within 1 year postoperatively. RESULTS: Twelve of 87 (14%) patients undergoing conversion THA developed infection. The mean erythrocyte sedimentation rate (37.2 vs 24.4 mm/h, P = .2062) and CRP (22.4 vs 9.0 mg/L, P = .0026) in the infected cohort were elevated compared to the noninfected group. An optimal cutoff value for CRP of 12 mg/L (area under the curve = 0.77, 95% confidence interval 0.58-0.97) revealed 75% sensitivity, 84% specificity, 43% positive predictive value, and 95% negative predictive value (P < .0001) in the entire cohort. CONCLUSIONS: Even without clinical signs and symptoms, patients undergoing conversion THA from internal fixation of hip/acetabular fractures are still at high risk for developing periprosthetic joint infection. All patients undergoing conversion THA should have CRP measured preoperatively as a part of the diagnostic workup for underlying infection. Further research should be devoted to creating a preoperative diagnostic algorithm incorporating CRP, similar to Musculoskeletal Infection Society criteria, dedicated to patients undergoing conversion THA. LEVEL OF EVIDENCE: Level III, Diagnostic retrospective cohort study.

Risk Factors for Readmission Following Revision Total Hip Arthroplasty in Patients Undergoing Surgery for Noninfective Causes.

Introduction Readmission following revision orthopedic surgery imposes tremendous costs due to the increased length of stay, procedure complexity, and revision surgery. Following revision total hip arthroplasty, as many as one in five patients are readmitted postoperatively. Readmissions cost the federal government $17.4 billion annually. The purpose of this study was to identify risk factors for unplanned readmission following revision total hip arthroplasty. Methods This was a retrospective case series review of randomized revision total hip arthroplasties (THA) patients between 2008 and 2018. Exclusions were as follows: outside hospital revisions, staged revisions, revisions for infection, and bilateral revisions. Data were collected by manual chart review. Readmissions were tracked from discharge until the final follow-up. Results A total of 61 patients and 85 revision THAs were analyzed. Nineteen patients (31.1%) were readmitted; 31.6% of the readmitted patients had a coronary artery disease compared to 6.5% of non-readmitted patients. Readmission was also associated with obesity, former smokers, and hypertension. Also, the mean duration of follow-up was 26.5 months for readmitted patients as compared to 8.96 for non-readmitted patients. Conclusion Obesity, former tobacco use, younger age, coronary artery disease (CAD), and hypertension were associated with readmission. The medical optimization of patients with these risk factors prior to surgery could significantly lower costs relative to revision THA.

Occult Radiographically Evident Port-Site Hernia After Robot-Assisted Urologic Surgery: Incidence and Risk Factors.

PURPOSE: Laparoscopic trocar-site hernias (TSH) are rare, with a reported incidence of 1% or less. The incidence of occult radiographically evident hernias has not been described after robot-assisted urologic surgery. We evaluated the incidence and risk factors of this problem. MATERIALS AND METHODS: A single-institution retrospective review of robot-assisted urologic surgery was performed from April 2009 to December 2012. Patients with preoperative and postoperative CT were included for analysis. Imaging was reviewed by two radiologists and one urologist. RESULTS: One hundred four cases were identified, including 60 partial nephrectomy, 38 prostatectomy, and 6 cystectomy. Mean age was 58 years and mean body mass index (BMI) was 29 kg/m(2). The cohort was 77% male. Ten total hernias were identified by CT in 8 patients, 2 of which were clinically evident hernias. Excluding these two hernias, occult port-site hernias were identified radiographically in seven patients. Per-patient incidence of occult TSH was 6.7% (7/104), and per-port incidence was 1.4% (8/564). All hernias were midline and 30% contained bowel. Eight of the 10 occurred at 12 mm sites (p = 0.0065) and 3 of the 10 occurred at extended incisions. Age, gender, BMI, smoking status, diabetes mellitus, immunosuppressive drug therapy, ASA score, procedure, blood loss, prior abdominal surgery, and history of hernia were not significant risk factors. Specimen size >40 g (p = 0.024) and wound infection (p = 0.0052) were significant risk factors. CONCLUSION: While the incidence of clinically evident port-site hernia remains low in robot-assisted urologic surgery, the incidence of CT-detected occult hernia was 6.7% in this series. These occurred most often in sites extended for specimen extraction and at larger port sites. This suggests more attention should be paid to fascial closure at these sites.