Septic Revision Research Articles

Inferior results at long-term follow-up after extensor mechanism allograft reconstruction in septic compared to aseptic revision total knee arthroplasty.

Extensor mechanism lesion after total knee arthroplasty (TKA) is a catastrophic complication. Reconstruction with extensor mechanism allograft (EMA) has been described as a sound salvage procedure. Its effectiveness at long term and in septic cases is still under scrutiny. The long-term results of EMA reconstruction for chronic extensor mechanism failures following aseptic and septic revision TKA have been analysed. From the institutional database, 35 patients with a revision TKA (RevTKA) undergoing EMA reconstruction from 2005 to 2015 have been retrospectively identified. A history of periprosthetic joint infection (PJI) was found in 13 (37%) patients. The mean follow-up was 81.2months (± 34.7, range 3-120). EMA failures were considered for lag more than 20°, Knee Society Score (KSS) less than 60 points, and/or in the case of revision of the allograft. The mean KSS improved from 35.9 (± 16.9, range 0-54) to 86.6 (± 10.4, range 54-99) points in the aseptic group (p < 0.001) and from 27.5 (± 11.6, range 10-44) to 79.4 (± 16.3, range 48-94) points in the septic group (p < 0.001). The extensor lag changed from 48.4° (± 14.5, range 30-90) to 4.6° (± 10.8, range 0-50) in the aseptic group (p < 0.001) and from 56.5° (± 20.8, range 30-90) to 6.1° (± 6.8, range 0-20) in the septic group (p < 0.001). The mean postoperative flexion was 105.2° (± 13.2, range 75-130) in the aseptic group and 102.7° (± 12.5, range 80-120) in the septic group (p = 0.32). Three failures (14% of the cases) occurred in the aseptic group and five in the septic group (38% of the cases). The overall survivorship at 10 years was 83.3% (22 cases, CI95 94.2-121.7) vs 58% (13 cases, CI95 67.2-111.7) in the aseptic and septic group, respectively (p = 0.01). EMA reconstruction after extensor mechanism disruptions in TKA is a reliable salvage procedure. The septic nature of the revision decreased the functionality of the knee joint after EMA, but it did not represent a risk factor for re-ruptures or recurrence of infection. Level III.

Can C-Reactive Protein-Lymphocyte Ratio Be Used as a Screening Tool to Confirm the Diagnosis of Periprosthetic Joint Infection?

This study aimed to investigate whether periprosthetic joint infection (PJI) can be predicted by the C-reactive protein-to-lymphocyte ratio (CLR), whether this ratio increases the accuracy of PJI diagnosis, and whether it is more sensitive than other blood values and ratios. The patients were divided into two groups: the septic revision (SR) group and the aseptic revision (AR) group. In cases of septic revision, the diagnosis of PJI was made based on the criteria proposed by the European Bone and Joint Infection Society (EBJIS). The groups were compared in terms of age, sex, body mass index, comorbidity, and preoperative laboratory results. The sensitivity, specificity, and diagnostic performance of the values and ratios were analyzed and compared. The receiver operating characteristic (ROC) analysis for the CLR gave a diagnostic value of 15.52, which provided a sensitivity of 91.1% and a specificity of 64.2% for PJI. The CLR gave lower specificity and higher sensitivity compared to the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) values. The ROC analysis showed that the CLR had a similar area under the curve (AUC) with the ESR and CRP (0.808). The CLR had a higher specificity than other ratios (platelet volume ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio) and a higher value of the AUC. In the multivariate analysis, the CLR (hazard ratio, 1.088; 95% confidence interval, 1.063-1.113; p < 0.001) was found to be a significant risk factor. As CLR increased by one unit, the risk of PJI increased by 1.088 times, and it was statistically significant (p < 0.001). The findings of this study suggest that CLR can serve as a valuable screening tool for diagnosing PJI. CLR demonstrated higher sensitivity in predicting PJI compared to ESR and CRP, and it exhibited greater specificity than other infection markers.

Clinical Outcomes and Infection Rates Following Revision Total Knee Arthroplasty: Aseptic Failure versus Septic Failure.

It is controversial whether revision total knee arthroplasty (TKA) due to septic failure shows inferior clinical outcomes compared with TKA due to aseptic failure. Moreover, few studies have compared the infection rates after revision TKA between aseptic and septic failure. We aimed to compare the clinical outcomes and infection rates after aseptic and septic revision TKA. Between April 2006 and May 2019, 68 and 26 patients underwent revision TKA due to aseptic failure (aseptic group) and septic failure (septic group), respectively. The postoperative range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis index, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), and infection rates were compared between the two groups. The mean follow-up durations in the aseptic and septic groups were 44.4 and 54.8 months, respectively. The septic group showed inferior postoperative ROM (124.1° and 109.4°, p = 0.004), KSKS (88.9 and 78.8, p = 0.001), and KSFS (72.8 and 59.0, p = 0.001). Three patients of aseptic group had infection. Three patients of septic group had recurred infection (same pathogen with the first infection) and 1 patient had a new infection (different pathogen). The septic group showed slightly higher but not significantly different infection rates (4.4% and 15.4%, p = 0.089). Revision TKA with septic failure showed inferior postoperative clinical outcomes compared with aseptic revision surgery. A slightly higher infection rate was observed in the septic group but it was not significantly different.

Successful eradication rate following one-stage septic knee and hip exchange in selected pre-operative culture-negative periprosthetic joint infections.

The main requirement for performing the one-stage septic exchange is the pre-operative identification of the pathogen and its susceptibility. The purpose of this study is to evaluate the success rate with special focus on reinfection in a cohort of patients who underwent one-stage septic knee or hip revision for pre-operative culture-negative PJI. We retrospectively analyzed 640 patients treated by one-stage revision for chronic knee or hip PJI between January 1, 2016, and December 31, 2018. Only cases with pre-operative culture-negative PJI, with culture-negative synovial aspirations and one negative open biopsy, were analyzed. We evaluated the septic and aseptic complication and the rate of complication-free survival defined as the time from the date of first operation and the date of complication events. A total of 22 patients fulfilled the inclusion and were enrolled. The mean age of the group was 73.2 ± 9.8years, with a median ASA score of 3 (range 3-4). After mean follow-up of 3.6 ± 2.6years, 86.4% (19 out of 22) of patients reported no complications. Two patients (9.1%) after one-stage hip required revision arthroplasty due to septic failure, while one patient (4.5%) with one-stage knee had revision for femoral component aseptic loosening. Our analysis suggests that the absence of pre-operative pathogen detection may not be contraindication to the one-stage revision in selected patients. The one-stage exchange might be considered in patients with pre-operative negative cultures in presence of ASA > 3 and multiple comorbidities that are not able to tolerate multiple surgeries.

Economics of Total Hip Arthroplasty: Review

This review article focuses on issues of economic analysis in providing care to patients requiring total hip arthroplasty. A large number of factors affecting the final financial result force us to look at economic research in the field of arthroplasty with a certain degree of criticality. At the same time, the existing financing systems cannot fully take into account all the possible costs arising from total hip arthroplasty. For this reason, studies concerning revision total hip arthroplasty are of particular interest, where treatment costs can vary significantly depending on the etiology and complexity of the case. These differences are reflected in the works of authors from France, Germany and Great Britain, who compared the treatment costs of patients with septic and aseptic revisions. Very different data both between countries and within the same country well demonstrate the need for a critical approach to the results of cost-effectiveness studies, QALYs based on Markov and other models, as the quality of the original data can be highly variable and reproduce the error of the initially incorrect price structure. At the same time, the rapidly increasing number of operations of primary and revision hip arthroplasty and, accordingly, the increasing economic costs of these operations require clear and effective economic criteria for their evaluation. The formation and application of these criteria will be the purpose of further research.

Diagnostic Value of C-Reactive Protein and Serum White Blood Cell Count during Septic Two-Stage Revision of Total Knee Arthroplasties.

In septic two-stage revision arthroplasty, the timing of reimplantation is crucial for therapeutic success. Recent studies have shown that singular values of C-reactive protein (CRP) and white blood cell count (WBC count) display weak diagnostic value in indicating whether periprosthetic joint infection (PJI) is controlled or not during two-stage revision surgery of knee arthroplasty. Therefore, in addition to the values of CRP and WBC, the course of CRP and WBC counts were compared between groups with and without later reinfection in 95 patients with two-stage revision (TSR) of infected total knee arthroplasties (TKA). Of these patients, 16 had a reinfection (16.84%). CRP values decreased significantly after the first stage of TSR in both the reinfection and no-reinfection groups. WBC count values decreased significantly in the no-reinfection group. Decrease in WBC count was not significant in the reinfection group. No significant difference could be found in either the CRP values or the WBC counts at the first stage of TSR, the second stage of TSR, or their difference between stages when comparing groups with and without reinfection. Area under the curve (AUC) values ranging between 0.631 and 0.435 showed poor diagnostic value for the calculated parameters. The courses of CRP over 14 days after the first stage of both groups were similar with near identical AUC. CRP and WBC count as well as their course over 14 days postoperatively are not suitable for defining whether a PJI of the knee is under control or not.

Single Wedge Femoral Stem Designs are Associated With a Higher Risk for Revision After Cementless Primary Total Hip Arthroplasty

BackgroundCementless total hip arthroplasty (THA) femoral stems are the most commonly selected prostheses in the United States. Optimal stem geometry remains controversial with excellent survivorship reported for many designs. We compared cause-specific stem revision of single-wedge versus double-wedge designs from a multicenter US cohort. MethodsData from an integrated healthcare network’s total joint replacement registry were used to conduct a cohort study. Primary elective cementless THAs were identified (2001 to 2018). Implant exposure groups were classified by design geometry using the system proposed by Khanuja et al. Type 1 single-wedge (n = 11,082) and type 2 double-wedge (n = 32,380) designs were compared, and other design types were excluded; the final study cohort comprised 43,462 THAs. Cause-specific multivariable Cox regressions were used to evaluate risk for revision due to infection or aseptic reasons, including loosening, instability, periprosthetic fracture, or other reasons. ResultsAfter adjustment for covariates, a higher aseptic revision risk was observed for type 1 when compared to type 2 designs (hazard ratio = 1.91, 95% confidence interval = 1.33-2.75). When looking at specific revision reasons, revision for aseptic loosening (hazard ratio = 3.46, 95% confidence interval = 2.24-5.34) was higher for type 1 versus type 2 designs. No differences were found for septic revision, instability, periprosthetic fracture, or revisions for other reasons. ConclusionsType 1 single-wedge designs were found to have a higher risk of revision due to aseptic loosening relative to type 2 double-wedge designs. Femoral stem geometry should be considered when selecting a cementless femoral implant. Level of EvidenceLevel III.

Two-Year Survivorship and Outcomes of a Three-Dimensional Printed Metaphyseal Cone in the Setting of Revision Total Knee Arthroplasty.

Poor metaphyseal fixation secondary to bone loss in revision total knee arthroplasty (TKA) continues to be challenging. One technique to increase implant stability is the use of novel three-dimensional (3D) printed titanium metaphyseal cones with adjunctive stems for added fixation. However, the survival of these novel constructs is poorly understood. Therefore, we sought to examine 3D-printed titanium metaphyseal cone components in revision TKA for aseptic as well as septic reasons and aimed to evaluate: (1) revision-free survivorships; (2) patient-reported outcomes measures (PROMs); (3) postoperative medical complications; and (4) radiographic outcomes. A consecutive series of 62 patients who underwent revision TKA with use of a titanium metaphyseal cone at a single institution between September 1, 2015 and May 31, 2021 were examined. The patients had a minimum follow-up period of 2 years (mean, 40 months, range, 24-72 months). PROMS included Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS-JR) scores at baseline and last clinical follow-up. Overall, when excluding infections, the combined implant survivorship was 96% (52 out of 54), while it was 95% (35 out of 57) for aseptic revisions and 100% (17 out of 17) for septic revisions. Reasons for revisions within the aseptic revision cohort included loosening (5%) as well as periprosthetic joint infections (PJIs) (7.5%). All failures following an index septic revision were due to PJI. Mean KOOS scores at baseline as well as at final follow-up was 43 points (range, 16-80) and 70 points (range, 34-100), respectively. None of the patients had medical complications. Other than the loosening reported (only femoral component), of the surviving patients no patients had evidence of progressive radiolucencies. The use of titanium cones in revision TKA provides good revision-free survivorship at 2 years. Further research is warranted on the longer-term survivorship of 3D-printed titanium cones. The current study has found that 3D-printed titanium cones can be incorporated as part of the revision knee surgeon's armamentarium.

Delaying Total Knee Arthroplasty More than 4 Weeks after Intra-Articular Knee Injection Does Not Further Decrease Risk of Septic Revision.

Hyaluronic acid (HA) and corticosteroid (CS) injections are utilized in symptom management for patients with osteoarthritis. However, contamination of the joint may increase the risk of infection following total knee arthroplasty (TKA). Therefore, the purpose of this study was to examine 90-day surgical site infection (SSI) and manipulation under anesthesia (MUA) as well as up to 2-year prosthetic joint infection (PJI) in intra-articular knee injection recipients prior to TKA compared with patients who did not have knee injections. We specifically assessed (1) timing of HA and CS prior to TKA; (2) type of intra-articular knee injection; as well as (3) associated risk factors. We queried a national database to identify patients who underwent primary TKA from September 2015 to October 2020 (n = 1.5 million). Patients with prior knee injections were stratified to five cohorts: HA within 4 weeks (n = 140), HA 4 to 6 weeks prior (n = 337), CS within 4 weeks (n = 2,344), CS 4 to 6 weeks (n = 2,422), and a no injection, control, cohort prior to TKA (n = 5,000). Bivariate chi-square analyses of outcomes were conducted, and multivariate regressions were used to adjust for comorbidities and assess associated risk factors. The adjusted analysis showed a significant risk in infection for patients receiving an injection within 4 weeks of TKA (p < 0.023) and showed no difference in type of injection (p > 0.050). Additionally, SSIs were increased 1.58 times in the CS within 4 weeks of TKA cohort (p = 0.023). However, no difference in MUA risk was shown at 90-day postoperative (p > 0.212). Furthermore, tobacco use was identified as a risk factor that further increased likelihood of PJI. Intra-articular knee injection less than 4 weeks before TKA increased the risk for PJI; however, past 4 weeks did not confer infection risk. Tobacco use was identified as an associated risk factor that further increased likelihood for PJI. These results highlight the need for surgeons to wait 4 weeks between knee injection and TKA to decrease risk of septic revision.

Knee Arthroscopy Prior to Total Knee Arthroplasty: Temporal Relationship to Surgical Complications.

Mechanical knee symptoms secondary to knee osteoarthritis (OA) may warrant knee arthroscopy (KA). Degenerative changes may progress and require a subsequent total knee arthroplasty (TKA). Recent studies have evaluated the timing of KA prior to TKA, associated a narrow interval with increased post-TKA complications. However, an updated analysis is required. We compared surgical outcomes in recipients of KA prior to TKA as stratified by four, time-dependent cohorts (< 12, 12 to 16, 16 to 20, and 20 to 24 weeks prior to TKA). We specifically compared: 90-day (1) manipulations under anesthesia (MUAs); (2) septic revisions at 90 days, 1 year, and 2 years; as well as (3) how various independent risk factors influenced the manipulations or revisions. We queried a national database for patients undergoing TKA. Patients who underwent KA with the following intervals: < 12 (n = 1,023), 12 to 16 (n = 816), 16 to 20 (n = 1,957), and 20 to 24 weeks (1,727) prior to TKA were compared with those patients who did not have a history of KA (n = 5,000). Bivariate analyses were utilized to assess 90 days through 2 years surgical outcomes. Afterwards, multivariate regression models were utilized to assess for independent risk factors. The unadjusted analyses showed an increase in MUA through 2 years among all the KA recipients (p < 0.001). Septic revisions and surgical site infections at all time points were not associated with any of the four arthroscopy time intervals (p > 0.476). The adjusted analyses showed an increased risk for 90-day MUA among all TKA cohorts (p < 0.001). Risk for septic revisions did not reach significance. Delaying TKA by 24 weeks in KA recipients was not associated with a decreased risk in septic revisions. However, there was an apparent risk of MUA at 90 days for all KA cohorts suggesting that waiting after KA before TKA makes no difference in MUA rates. These results update existing literature, may serve as an adjunct to current practice guidelines, and can contribute to shared decision making in the preoperative setting.

Ultrasonic bone cement removal efficiency in total joint arthroplasty revision: A computer tomographic-based cadaver study.

Polymethylmethacrylate (PMMA) removal during septic total joint arthroplasty revision is associated with a high fracture and perforation risk. Ultrasonic cement removal is considered a bone-preserving technique. Currently, there is still a lack of sound data on efficacy as it is difficult to detect smaller residues with reasonable technical effort. However, incomplete removal is associated with the risk of biofilm coverage of the residue. Therefore, the study aimed to investigate the efficiency of ultrasonic-based PMMA removal in a human cadaver model.The femoral components of a total hip and a total knee prosthesis were implanted in two cadaver femoral canals by 3rd generation cement fixation technique. Implants were then removed. Cement mantle extraction was performed with the OSCAR-3-System ultrasonic system (Orthofix®). Quantitative analysis of cement residues was carried out with dual-energy and microcomputer tomography.With a 20 µm resolution, in vitro microcomputer tomography visualized tiniest PMMA residues. For clinical use, dual-energy computer tomography tissue decomposition with 0.75 mm resolution is suitable. With ultrasound, more than 99% of PMMA was removed. Seven hundred thirty-fourresidues with a mean volume of 0.40 ± 4.95 mm3 were identified with only 4 exceeding 1 cm in length in at least one axis.Ultrasonic cement removal of PMMA was almost complete and can therefore be considered a highly effective technique. For the first time, PMMA residues in the sub-millimetre range were detected by computer tomography. Clinical implications of the small remaining PMMA fraction on the eradication rate of periprosthetic joint infection warrants further investigations.

The Influence of Dorr Type and Femoral Fixation on Outcomes Following Total Hip Arthroplasty for Acute Femoral Neck Fractures: A Multicenter Study

BackgroundThe American Academy of Orthopaedic Surgeons guidelines report moderate evidence for cementing femoral stems for hip fractures, mainly derived from hemiarthroplasty literature. This is the first large, nonregistry study examining the influence of femoral fixation, implant type, patient characteristics, and radiographic factors on outcomes after total hip arthroplasty (THA) for acute femoral neck fractures. MethodsA multicenter retrospective study was performed of 709 THA cases (199 cemented, 510 cementless) for femoral neck fractures from 2006 to 2020 at three large academic institutions. Demographics, perioperative characteristics, and radiographs were reviewed. Kaplan-Meier survivorship curves were generated for multiple outcomes. Univariate and multivariate analyses were performed with P ≤ .05 denoting significance. ResultsCementless stems had a higher all-cause aseptic femoral revision rate (5.1 versus 0.5%, P = .002) and periprosthetic femoral fracture rate (4.3 versus 0%, P = .001). Each successive Dorr type had a higher fracture rate with cementless implants: 2.3%, 3.7%, and 15.9% in Dorr A, B, and C, respectively (P < .001). Logistic regression analyses confirmed that cementless stems (P = .02) and Dorr C bone (P = .001) are associated with periprosthetic fractures; collared implants and prophylactic cables did not protect against fractures. There was no difference in rates of dislocation, septic revision, or mortality between groups. ConclusionCementless stems during THA for femoral neck fractures have a higher aseptic femoral revision rate, specifically for periprosthetic fractures. Dorr C bone was particularly prone with an alarmingly high fracture rate. All fractures occurred in cementless cases, suggesting that cemented stems may minimize this complication. Level of EvidenceIII.

Tapered Modular Femoral Stems for Revision Total Hip Arthroplasty Show Excellent Mid-Term Survivorship.

Revision total hip arthroplasty (THA) can be challenging in the face of proximal femoral bone loss, catastrophic implant failure, or recurrent hip instability. Tapered modular femoral stems have shown substantial success at short follow up for aseptic revisions. The purpose of this study was to report mid-term revision THA outcomes of a tapered modular femoral stem at a tertiary referral center used to treat both aseptic as well as periprosthetic joint infections (PJIs). We specifically sought to assess: (1) revision-free implant survivorship; (2) patient-reported outcome measurements (i.e., Hip Disability and Osteoarthritis Outcome Score, Joint Replacement [HOOS JR]); (3) postoperative surgical complications and 30-day readmissions; as well as (4) radiographic outcomes. We reviewed a consecutive series of 92 patients who underwent revision THA between 2009 and 2013 with a tapered modular femoral stem. After accounting for mortality (n=7) and loss to follow up (n=13), a total of 72 implants in 66 patients who had eight years of mean follow up (range, 2 to 11) were included. PJI (46%) was the predominant preoperative indication for revision THA, followed by aseptic loosening (25%), periprosthetic fracture (18%), and symptomatic hardware (10%). Outcomes of interest included all-cause revision-free survivorship, postoperative complications, and HOOS JR, as well as SF-12 scores. Radiographically, they were evaluated for subsidence, radiolucencies, and loosening. Aseptic revision-free survivorship of the femoral component was 95.8% (69 out of 72). Including septic cases, revision-free survivorship was 87.5% (63 cases), and 60 implants (83.3%) had an all-cause revision-free survivorship. For those patients who underwent septic revisions, eight out of nine remained infection free, while one underwent a resection arthroplasty. Furthermore, the cause for femoral aseptic revisions were subsidence (1.4%) and aseptic loosening (2.8%). Functional score improvements for HOOS JR, SF-12 PCS, as well as MCS were 29, 13, and 2, respectively (all p<0.001). There were eight emergency department visits (11.1%,) and six inpatient readmissions (8.3%). Additionally, two patients had dislocations (2.8%, two out of 72) not requiring revision. There were two cases of femoral subsidence and one aseptic loosening requiring revision; whereas, the rest did not demonstrate any progressive radiographic lucencies. The eight-year mean survivorship results of the tapered modular femoral stems in revision THA demonstrated excellent results. Our series found improved outcome scores and relatively low postoperative complications, which indicate a favorable implant survivorship profile for revision THA. These results serve to inform arthroplasty surgeons of expected outcomes of the modular stems when used for patients who need complex revision THA.

Is 2-Stage Septic Revision Worth the Money? A Cost-Utility Analysis of a 1-Stage Versus 2-Stage Septic Revision of Total Knee Arthroplasty

BackgroundTwo-stage exchange arthroplasty remains the gold standard for the management of prosthetic joint infection (PJI) of the knee, but several studies have demonstrated that 1-stage exchange is as effective as 2-stage exchange. This study aimed to support decision-making via an economic evaluation of 1-stage compared to 2-stage exchange for total knee arthroplasty septic revision in patients who did not have compelling indication PJI (ie, Methicillin-resistant Staphylococcus aureus, multiorganism, systemic sepsis, comorbidities, culture negative, resistant organism, and immunocompromised) to undergo a 2-stage exchange. MethodsA cost-utility analysis was performed using a Markov cohort model from the health care provider perspective using Australia data. One-stage septic knee revisions were compared with 2-stage exchange procedures for chronic PJI using a patient-lifetime horizon. Health outcomes were expressed as quality-adjusted life-years (QALY), whereas costs were presented in 2020 Australian dollars. Sensitivity analyses, population expected values of perfect information, and the perfect information for parameters (EVPPI) were assessed to estimate the opportunity costs surrounding the decision made at a willingness-to-pay threshold of $50,000 per QALY. ResultsThe incremental cost-effectiveness ratio of 2-stage exchange compared with 1-stage exchange was $231,000 per QALY, with 98.5% of the probabilistic sensitivity simulations above the willingness-to-pay threshold. The population expected value of perfect information was $882,000, whereas the expected value of perfect information for parameters for the “cost parameters” was $207,000. ConclusionThe adoption of 1-stage septic knee revision is the optimal choice for patients who have a PJI and who do not have a compelling need for a 2-stage exchange arthroplasty. One-stage exchange for PJI should be advocated in patients who meet the eligibility criteria.

Hepatitis C Is Associated With Higher Short-Term Complication Rates After Initial Aseptic and Septic Revision Total Hip Arthroplasty: A Matched Cohort Study

BackgroundIt is unclear if hepatitis C virus (HCV) negatively impacts outcomes of revision total hip arthroplasty (rTHA). The purpose of this study is to trend recent rTHA utilization in patients who have HCV and compare postoperative complication rates versus a matched cohort. MethodsAll patients who underwent rTHA were retrospectively identified in a national database. Patients who had HCV (n = 1,746) were matched 1:3 with a matching group (n = 5,238) for age, gender, and several comorbidities. Cochran-Armitage tests were used to analyze trends in the annual proportion of rTHA performed in patients who had HCV from 2010 to 2019. Rates of 90-day medical and prosthesis-related complications within 2 years postoperatively were compared with multivariable logistic regressions. ResultsThe annual proportion of rTHA performed in patients who had HCV significantly increased from 2010 to 2019 (P < .001). Patients who had HCV exhibited significantly higher rates of acute kidney injuries (7.6% versus 4.4%; odds ratio [OR] 1.50), transfusions (20.6% versus 14.6%; OR 1.38), and re-revisions for prosthetic joint infection (10.9% versus 6.5%; OR 1.73). In subgroup analyses, rates of re-revision for prosthetic joint infection after initial aseptic rTHA (7.1% versus 3.8%; OR 1.82) and periprosthetic fracture after initial septic rTHA (4.5% versus 1.6%; OR 2.77) were significantly higher in the HCV cohort. ConclusionSimilar to primary THA, patients who have HCV exhibit significantly increased complication rates after rTHA. With growing utilization in recent years, these data suggest that this population will comprise an increasingly larger proportion of rTHA procedures performed in the coming years.

The Incidence of Severe Hypercalcaemia-Induced Mental Status Changes in Patients Treated with Antibiotic-Loaded Calcium Sulphate Depot for Orthopaedic Infections.

Local application of antibiotics with calcium-containing carrier materials (CCCM) might deliver large quantities of calcium, with some cases of hypercalcaemia reported. The incidence of symptomatic hypercalcaemia was estimated retrospectively in a consecutive, prospective series of patients treated between 10/2006 and 02/2019 with antibiotic-loaded CCCM for various orthopaedic infections. Risk factors were analysed. In the study period, 215 CCCM applications were performed. Two patients (0.9%) developed symptomatic hypercalcaemia. In one case, hypercalcaemia occurred 14 days after a second CCCM application during a staged septic hip revision. In the other case, hypercalcaemia became symptomatic six days after application of vancomycin-loaded CCCM in a component-retaining septic revision hip arthroplasty. In both cases, hypercalcemia was not imputable solely to the CCCM. Prolonged immobilization, renal impairment and other specific risk factors were present. Implantation of a CCCM for local application of antibiotics exposes the patient to large quantities of calcium during dissolution. This might induce symptomatic hypercalcaemia, a potentially life-threatening complication. The observed incidence of symptomatic hypercalcaemia remained rare (<1%). In some patients, compensatory mechanisms might be overwhelmed in the presence of other risk factors. Postoperative monitoring of calcaemia as well as elimination of risk factors is mandatory for all patients treated with CCCM.

What’s New in Hip Replacement

What’s New in Hip Replacement

Diagnostic Value of CRP and Serum WBC Count during Septic Two-Stage Revision of Total Hip Arthroplasties.

The diagnostic value of C-reactive protein (CRP) and the serum white blood cell (WBC) count is still barely defined for decision making during septic two-stage revision surgery of hip arthroplasty. We, therefore, compared these values between stages as well as between the groups without and with reinfection in 117 patients. A total of 106 patients were reinfection-free (91%). The median follow-up was 51 months. With a ΔCRP of −10 mg/L and a ΔWBC count of −1000/µL, a significant decrease between stages (p = 0.001) could be observed. When comparing the CRP and WBC count values between groups, however, no significant difference was found at stage one, stage two and even the difference between these two time points (reinfection-free ΔCRP of −11 mg/L and ΔWBC count of −1000/µL vs. reinfection ΔCRP of −5 mg/L (p = 0.131) and ΔWBC count of −1100/µL) (p = 0.424). The diagnostic value was poor for the calculated parameters (area under the curve (AUC) 0.5–0.6). The courses of the mean CRP values of both groups were similar. We conclude that the CRP and WBC count are not helpful to guide the decision making in individual cases.

Poster 252: Revision Risk of Hamstring Versus Hybrid Graft in Anterior Cruciate Ligament Reconstruction

Objectives:Hamstring autograft (HA) is a commonly used graft for anterior cruciate ligament reconstruction (ACLR). Hamstring tendon harvest can occasionally result in a small diameter graft, leaving the surgeon with several options. One option is to augment the hamstring graft with allograft tendon to increase the combined graft diameter forming a hybrid graft (HG). Inconsistent results of HG reconstructions have been reported, with some studies reporting worse outcomes for HG while others showing no difference between the two types of grafts. However, these studies have small sample sizes or are of an older patient population. The purpose of our study was to compare the revision rates of HA versus HG grafts in a young patient population.Methods:We conducted a retrospective cohort study of prospectively collected data from our integrated healthcare system’s ACLR Registry. Patients <25 years of age with a primary, isolated ACLR performed between 2005-2020 were identified; those with prior surgery in the index knee, double bundle, and infections (septic revisions) were excluded. The exposure of interest was graft type and diameter size, including <8mm HA and >8mm HG. Hybrid graft was defined as a hamstring tendon augmented with an allograft tendon to increase the graft diameter. Grafts with unknown diameter sizes and other graft types were excluded. A secondary analysis examined 7mm and 7.5mm HA vs >8mm HG. Propensity score-weighted Cox proportional hazard regression was used to evaluate the risk of aseptic revision during follow-up. Propensity score weights were calculated prior to evaluation of the outcome using multivariable logistic regression analysis and included age, sex, body mass index, race/ethnicity, femoral fixation, tibial fixation, femoral tunnel method, and activity at injury. Hazard ratios (HR) and 95% confidence intervals (CI) are presented. A P<0.05 was considered statistically significant.Results:The final cohort comprised 1,945 ACLR (548 were >8mm HG and 1397 were <8mm HA, including 651 with 7mm diameters and 672 with 7.5mm). At 8-years follow-up, the crude cumulative aseptic revision probability for >8mm HG was 9.1%, while <8mm HA was 10.9% (Figure 1); corresponding cumulative probabilities for 7mm and 7.5mm HA were 11.1% and 11.2% respectively. After adjustment with propensity score weighting, we failed to observe a difference in aseptic revision risk for <8mm HA compared with >8mm HG (HR=1.15, 95% CI = 0.72-1.82, p=0.56) (Table 1). Similarly, no difference was observed for 7mm HA (HR= 1.23, 95% CI=0.71-2.11, p=0.46) and 7.5mm HA (HR=1.16, 95% CI =0.74-1.82, p=0.52) compared to HG.Conclusions:In our cohort study of 1,945 patients, we failed to detect a statistical difference in the risk of aseptic revision between a HA < 8mm and a HG > 8mm. The clinical significance is that augmentation of HA with an allograft does not appear to decrease the risk of aseptic revision and may not be necessary. Future studies should be conducted to confirm these findings.Figure 1.Cumulative Incidence of Aseptic Revision by Graft Type/Diameter Size.Table 1.Crude Cumulative Revision Probability And Adjusted Risk After Aclr By Graft Type/Diameter Size.

Role of joint aspiration before re-implantation in patients with a cement spacer in place.

BACKGROUNDThe usefulness of a mandatory joint aspiration before re-implantation in patients with a cement spacer already in place is unclear.AIMTo evaluate the role of culturing synovial fluid obtained by joint aspiration before re-implantation in patients who underwent a two-stage septic revision.METHODSA retrospective observational study was conducted, including patients that underwent a two-stage septic revision (hip or knee) from 2010 to 2017. After the first stage revision and according to intraoperative culture results, all patients were treated with an antibiotic protocol for 6-8 wk. Following 2 wk without antibiotics, a culture of synovial fluid was obtained. The results of these cultures were recorded and compared with cultures obtained during re-implantation surgery.RESULTSForty-one patients (20 hip and 21 knee spacers) were included in the final analysis. In 39 cases, the culture of synovial fluid was negative, while in the remaining 2 cases (knee spacers) no analysis was possible due to dry tap. In 5 of the patients, two or more intraoperative cultures taken during the re-implantation surgery were positive.CONCLUSIONWe found no evidence to support mandatory joint aspiration before re-implantation in patients with a cement spacer in place.