Complete blood platelet and lymphocyte ratios increase diagnostic accuracy of periprosthetic joint infection following total hip arthroplasty.

INTRODUCTION: Systemically, changes in serum platelet to lymphocyte ratio (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil to lymphocyte ratio (NLR) and monocyte to lymphocyte (MLR) represent primary responses to early inflammation and infection. This study aimed to determine whether PLR, PVR, NLR, and MLR can be useful in diagnosing periprosthetic joint infection (PJI) in total hip arthroplasty (THA) patients. METHODS: A total of 464 patients that underwent revision THA with calculable PLR, PVR, NLR, and MLR in 2 groups was evaluated: 1) 191 patients with a pre-operative diagnosis of PJI, and 2) 273 matched patients treated for revision THA for aseptic complications. RESULTS: The sensitivity and specificity of PLR combined with erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), synovial white blood cell count (WBC) and synovial polymorphonuclear leukocytes (PMN) (97.9%; 98.5%) is significantly higher than only ESR combined with CRP, synovial WBC and synovial PMN (94.2%; 94.5%; p < 0.01). The sensitivity and specificity of PVR combined with ESR, CRP and synovial WBC, and synovial PMN (98.4%; 98.2%) is higher than only ESR combined with CRP, synovial WBC and synovial PMN (94.2%; 94.5%; p < 0.01). CONCLUSION: The study results demonstrate that both PLR and PVR calculated from complete blood counts when combined with serum and synovial fluid markers have increased diagnostic sensitivity and specificity in diagnosing periprosthetic joint infection in THA patients. LEVEL OF EVIDENCE: III, case-control retrospective analysis.

Artificial neural networks for the prediction of transfusion rates in primary total hip arthroplasty.

BACKGROUND: Despite advancements in total hip arthroplasty (THA) and the increased utilization of tranexamic acid, acute blood loss anemia necessitating allogeneic blood transfusion persists as a post-operative complication. The prevalence of allogeneic blood transfusion in primary THA has been reported to be as high as 9%. Therefore, this study aimed to develop and validate novel machine learning models for the prediction of transfusion rates following primary total hip arthroplasty. METHODS: A total of 7265 consecutive patients who underwent primary total hip arthroplasty were evaluated using a single tertiary referral institution database. Patient charts were manually reviewed to identify patient demographics and surgical variables that may be associated with transfusion rates. Four state-of-the-art machine learning algorithms were developed to predict transfusion rates following primary THA, and these models were assessed by discrimination, calibration, and decision curve analysis. RESULTS: The factors most significantly associated with transfusion rates include tranexamic acid usage, bleeding disorders, and pre-operative hematocrit (< 33%). The four machine learning models all achieved excellent performance across discrimination (AUC > 0.78), calibration, and decision curve analysis. CONCLUSION: This study developed machine learning models for the prediction of patient-specific transfusion rates following primary total hip arthroplasty. The results represent a novel application of machine learning, and has the potential to improve outcomes and pre-operative planning. LEVEL OF EVIDENCE: III, case-control retrospective analysis.

Impact of Preoperative Opioid Use on Patient-Reported Outcomes after Revision Total Knee Arthroplasty: A Propensity Matched Analysis.

This is a retrospective study. Prior studies have characterized the deleterious effects of narcotic use in patients undergoing primary total knee arthroplasty (TKA). While there is an increasing revision arthroplasty burden, data on the effect of narcotic use in the revision surgery setting remain limited. Our aim was to characterize the effect of active narcotic use at the time of revision TKA on patient-reported outcome measures (PROMs). A total of 330 consecutive patients who underwent revision TKA and completed both pre- and postoperative PROMs was identified. Due to differences in baseline characteristics, 99 opioid users were matched to 198 nonusers using the nearest-neighbor propensity score matching. Pre- and postoperative knee disability and osteoarthritis outcome score physical function (KOOS-PS), patient reported outcomes measurement information system short form (PROMIS SF) physical, PROMIS SF mental, and physical SF 10A scores were evaluated. Opioid use was identified by the medication reconciliation on the day of surgery. Propensity score-matched opioid users had significantly lower preoperative PROMs than the nonuser for KOOS-PS (45.2 vs. 53.8, p < 0.01), PROMIS SF physical (37.2 vs. 42.5, p < 0.01), PROMIS SF mental (44.2 vs. 51.3, p < 0.01), and physical SF 10A (34.1 vs. 36.8, p < 0.01). Postoperatively, opioid-users demonstrated significantly lower scores across all PROMs: KOOS-PS (59.2 vs. 67.2, p < 0.001), PROMIS SF physical (43.2 vs. 52.4, p < 0.001), PROMIS SF mental (47.5 vs. 58.9, p < 0.001), and physical SF 10A (40.5 vs. 49.4, p < 0.001). Propensity score-matched opioid-users demonstrated a significantly smaller absolute increase in scores for PROMIS SF Physical (p = 0.03) and Physical SF 10A (p < 0.01), as well as an increased hospital length of stay (p = 0.04). Patients who are actively taking opioids at the time of revision TKA report significantly lower preoperative and postoperative outcome scores. These patients are more likely to have longer hospital stays. The apparent negative effect on patient reported outcomes after revision TKA provides clinically useful data for surgeons in engaging patients in a preoperative counseling regarding narcotic use prior to revision TKA to optimize outcomes.

The utilization of artificial neural networks for the prediction of 90-day unplanned readmissions following total knee arthroplasty.

BACKGROUND: A reliable predictive tool to predict unplanned readmissions has the potential to lower readmission rates through targeted pre-operative counseling and intervention with respect to modifiable risk factors. This study aimed to develop and internally validate machine learning models for the prediction of 90-day unplanned readmissions following total knee arthroplasty. METHODS: A total of 10,021 consecutive patients underwent total knee arthroplasty. Patient charts were manually reviewed to identify patient demographics and surgical variables that may be associated with 90-day unplanned hospital readmissions. Four machine learning algorithms (artificial neural networks, support vector machine, k-nearest neighbor, and elastic-net penalized logistic regression) were developed to predict 90-day unplanned readmissions following total knee arthroplasty and these models were evaluated using ROC AUC statistics as well as calibration and decision curve analysis. RESULTS: Within the study cohort, 644 patients (6.4%) were readmitted within 90 days. The factors most significantly associated with 90-day unplanned hospital readmissions included drug abuse, surgical operative time, and American Society of Anaesthesiologist Physical Status (ASA) score. The machine learning models all achieved excellent performance across discrimination (AUC > 0.82), calibration, and decision curve analysis. CONCLUSION: This study developed four machine learning models for the prediction of 90-day unplanned hospital readmissions in patients following total knee arthroplasty. The strongest predictors for unplanned hospital readmissions were drug abuse, surgical operative time, and ASA score. The study findings show excellent model performance across all four models, highlighting the potential of these models for the identification of high-risk patients prior to surgery for whom coordinated care efforts may decrease the risk of subsequent hospital readmission. LEVEL OF EVIDENCE: Level III, case-control retrospective analysis.

Outcome of Two-Stage Revision Total Hip and Knee Arthroplasty as a Salvage Procedure for Deep Infection of Peri-Articular Fracture Fixation: Propensity Score-Matched Study.

Background: Failed open reduction internal fixation (ORIF) of peri-articular fractures due to deep infection is associated with decreased functional outcomes and increased mortality rates. Two-stage revision total joint arthroplasty (TJA) is often needed as a salvage procedure. The aim of this study was to evaluate the outcome of two-stage revision total hip and knee arthroplasty as a salvage procedure for the treatment of deep infection of peri-articular fracture fixation. Methods: Using propensity score-matching, a total of 120 patients was evaluated: 1) 40 consecutive patients were treated with planned salvage two-stage revision for the treatment of deep peri-articular infection, and 2) a control group of 80 patients who underwent two-stage revision for periprosthetic joint infection (PJI) after non-IF TJA. An infection occurred after a fracture of the acetabulum (27.5%), femoral neck (22.5%), intertrochanteric femur (15.0%), subtrochanteric femur (5.0%), femoral shaft (7.5%), distal femur (5.0%), and tibia (15.0%). Results: At an average follow up of 4.5 years (range, 1.0-25.8), the overall failure rate was 42.5% for the IF group compared to 21.3% for the non-ORIF group (P=0.03). There was a significantly higher reinfection rate for the IF group compared to the non-IF group (35.0% vs. 11.3%, p=0.005). Tissue cultures for the IF patients demonstrated significantly higher polymicrobial growth (30.0% vs. 11.3%, P=0.01) and methicillin-resistant Staphylococcus aureus (20.0% vs. 7.5%, P=0.04). Conclusion: Salvage two-stage revision arthroplasty for infected IF of peri-articular fractures was associated with poor outcome. The overall post-operative complications after salvage two-stage revision for infected IF of peri-articular fractures was high with 35% reinfection rates associated with the presence of mixed and resistant pathogens.

Insurance Payer Type Affects Outcomes after Revision Total Joint Arthroplasty: A Matched Cohort Analysis.

Background: The aim of this study is to evaluate the potential effects of insurance payer type on the postoperative outcomes following revision TJA. Methods: A single-institution database was utilized to identify 4,302 consecutive revision THA and TKA. Patient demographics and indications for revision were collected and compared based on patient insurance payer type: (1) Medicaid, (2) Medicare, and (3) private. Propensity score matching and, subsequent, multivariate regression analyses were applied to control for baseline differences between payer groups. Outcomes of interest were rates of complications occurring perioperatively and 90 days post-discharge. Results: After propensity-score-based matching, a total of 2,328 patients remained for further multivariate regression analyses (300 [12.9%] Medicaid, 1022 [43.9%] Medicare, 1006 [43.2%] private). Compared to privately insured patients, Medicaid and Medicare patients had 71% (P<0.01) and 53% (P=0.03) increased odds, respectively, for developing an in-hospital complication. At 90 days post-discharge, compared to privately insured patients, Medicaid and Medicare patients had 88% and 43% odds, respectively, for developing overall major complications. Conclusion: Our propensity-score-matched cohort study found that, compared to privately insured patients, patients with government-sponsored insurance were at an increased risk for developing both major or minor complications perioperatively and at 90-days post-discharge for revision TJA. This suggests that insurance payer type is an independent risk factor for poor outcomes following revision TJA.

The Utility of Machine Learning Algorithms for the Prediction of Early Revision Surgery After Primary Total Hip Arthroplasty.

BACKGROUND: Revision total hip arthroplasty (THA) is associated with increased morbidity, mortality, and healthcare costs due to a technically more demanding surgical procedure when compared with primary THA. Therefore, a better understanding of risk factors for early revision THA is essential to develop strategies for mitigating the risk of patients undergoing early revision. This study aimed to develop and validate novel machine learning (ML) models for the prediction of early revision after primary THA. METHODS: A total of 7,397 consecutive patients who underwent primary THA were evaluated, including 566 patients (6.6%) with confirmed early revision THA (<2 years from index THA). Electronic patient records were manually reviewed to identify patient demographics, implant characteristics, and surgical variables that may be associated with early revision THA. Six ML algorithms were developed to predict early revision THA, and these models were assessed by discrimination, calibration, and decision curve analysis. RESULTS: The strongest predictors for early revision after primary THA were Charlson Comorbidity Index, body mass index >35 kg/m2, and depression. The six ML models all achieved excellent performance across discrimination (area under the curve >0.80), calibration, and decision curve analysis. CONCLUSION: This study developed ML models for the prediction of early revision surgery for patients after primary THA. The study findings show excellent performance on discrimination, calibration, and decision curve analysis for all six candidate models, highlighting the potential of these models to assist in clinical practice patient-specific preoperative quantification of increased risk of early revision THA.

Artificial intelligence algorithms accurately predict prolonged length of stay following revision total knee arthroplasty.

PURPOSE: Although the average length of hospital stay following revision total knee arthroplasty (TKA) has decreased over recent years due to improved perioperative and intraoperative techniques and planning, prolonged length of stay (LOS) continues to be a substantial driver of hospital costs. The purpose of this study was to develop and validate artificial intelligence algorithms for the prediction of prolonged length of stay for patients following revision TKA. METHODS: A total of 2512 consecutive patients who underwent revision TKA were evaluated. Those patients with a length of stay greater than 75th percentile for all length of stays were defined as patients with prolonged LOS. Three artificial intelligence algorithms were developed to predict prolonged LOS following revision TKA and these models were assessed by discrimination, calibration and decision curve analysis. RESULTS: The strongest predictors for prolonged length of stay following revision TKA were age (> 75 years; p < 0.001), Charlson Comorbidity Index (> 6; p < 0.001) and body mass index (> 35 kg/m2; p < 0.001). The three artificial intelligence algorithms all achieved excellent performance across discrimination (AUC > 0.84) and decision curve analysis (p < 0.01). CONCLUSION: The study findings demonstrate excellent performance on discrimination, calibration and decision curve analysis for all three candidate algorithms. This highlights the potential of these artificial intelligence algorithms to assist in the preoperative identification of patients with an increased risk of prolonged LOS following revision TKA, which may aid in strategic discharge planning. LEVEL OF EVIDENCE: IV.

Posterior Tibial Slope Increases Anterior Cruciate Ligament Stress in Bi-Cruciate Retaining Total Knee Arthroplasty: In Vivo Kinematic Analysis.

The study design involved here is experimental in nature. The resection of the anterior cruciate ligament (ACL) during conventional total knee arthroplasty (TKA) has been considered a potential factor leading to abnormal in vivo knee kinematics. Bi-cruciate retaining (BCR) TKA designs allow the preservation of the ACL with the potential to restore native knee kinematics. This study aimed to investigate the effect of posterior tibial slope (PTS) on stress experienced by the ACL during weight bearing sit-to-stand (STS) and single-leg deep lunge. The ACL elongation patterns were measured in 30 unilateral BCR TKA patients during weight-bearing STS and single-leg deep lunge using a validated dual fluoroscopic tracking technique. The minimum normalized stress within the anteromedial (AM) and posterolateral (PL) bundle of the ACL during weight-bearing STS and single-leg deep lunge was found at a PTS of 3.7 degrees. The maximum AM and PL bundle stresses were observed at a PTS of 8.5 and 9.3 degrees, respectively during STS and at 8.4, and 9.1 degrees, respectively during single-leg deep lunge. There was a significant positive correlation between PTS and stress observed within the AM and PL bundle of the ACL during weight-bearing STS (R 2 = 0.37; p < 0.01; R2 = 0.36; p = 0.01) and single-leg deep lunge (R 2 = 0.42; p < 0.01; R 2 = 0.40; p < 0.01). The study demonstrates that PTS of operated BCR TKA knees has a significant impact on the stress experienced by the preserved ACL during weight-bearing STS and single-leg deep lunge. This suggests that avoiding excessive PTS may be one of the surgical implant alignment factors to consider during surgery to minimize increased loading of the preserved ACL.

Periprosthetic joint infection is the main reason for failure in patients following periprosthetic fracture treated with revision arthroplasty.

INTRODUCTION: Periprosthetic fracture after primary total hip and knee arthroplasty (THA; TKA) can be challenging, requiring open reduction internal fixation (ORIF), revision, or both. The aim of this study was to evaluate the outcomes and risk factors associated with re-revision surgery following failed revision arthroplasty for periprosthetic fracture. METHODS: A total of 316 consecutive THA patients and 79 consecutive TKA patients underwent a revision for periprosthetic fracture, of which 68 THA patients (21.5%) and 15 TKA patients (18.9%) underwent re-revision surgery. The most common indication for hip and knee re-revision was periprosthetic joint infection (PJI) in 28 THA patients (46.6%) and 11 TKA patients (47.8%). RESULTS: The complication rates of THA and TKA revision were 24.3% and 25.3% respectively, and 35.0% and 39.1% respectively for re-revision surgery at an average follow-up of 4.5 years. Periprosthetic joint infection was the most common indication for THA and TKA re-revision (46.7%; 47.8%) and third revision surgery (15.0%; 13.0%). Factors significantly contributing to an increased risk of THA and TKA re-revision included revision with plate fixation and revision with combined ORIF. CONCLUSION: The overall complication rate of THA and TKA re-revision surgery following failed revision surgery for periprosthetic fracture was higher than of revision surgery. The most common indication for re-revision and third revision was periprosthetic joint infection. These findings may assist surgeons in the management and preoperative counseling of patients undergoing THA and TKA revision surgery for a periprosthetic fracture to optimize the outcomes for these patients. LEVEL OF EVIDENCE: Level III, case-control retrospective analysis.

Outcome and risk factors of failures associated with revision total hip arthroplasty for recurrent dislocation.

INTRODUCTION: Recurrent dislocation represents the third most common cause of revision surgery after total hip arthroplasty (THA). However, there is a paucity of information on the outcome of revision total hip arthroplasty for recurrent dislocation. In this study, we investigated (1) clinical outcomes of patients that underwent revision THA for recurrent dislocation, and (2) potential risk factors associated with treatment failure in patients who underwent revision total hip arthroplasty for recurrent dislocation. METHODS: We retrospectively reviewed 211 consecutive cases of revision total hip arthroplasty for recurrent dislocation, 81 implanted with a constrained liner and 130 with a non-constrained liner with a large-diameter femoral head (> 32 mm). Patient- and implant-related risk factors were analyzed in multivariate regression analysis. RESULTS: At 4.6-year follow-up, 32 of 211 patients (15.1%) underwent re-revision surgery. The most common causes for re-revision included infection (14 patients) and dislocation (10 patients). Kaplan-Meier analysis demonstrates a 5-year survival probability of 77% for patients that underwent revision THA for recurrent dislocation. Osteoporosis, obesity (BMI ≥ 40), spine disease and abductor deficiency are independent risk factors for failure of revision surgery for recurrent dislocation. Liner type (constrained vs. non-constrained) was found not to be associated with failure of revision THA for recurrent dislocation (p = 0.44). CONCLUSION: This study suggests that THA revision for recurrent dislocation is associated with a high re-revision rate of 15% at mid-term follow-up. Osteoporosis, obesity (BMI ≥ 40) spine disease and abductor deficiency were demonstrated to be independent risk factors for failure of revision THA for recurrent dislocation. LEVEL OF EVIDENCE: Level III, case-control retrospective analysis.

The Effect of Joint Line Elevation on In Vivo Knee Kinematics in Bicruciate Retaining Total Knee Arthroplasty.

Prior studies have reported a negative effect on both clinical outcomes and patient-reported outcome measures (PROMS) following joint line elevation (JLE) in cruciate-retaining (CR) total knee arthroplasty (TKA) and posterior stabilized (PS) TKA designs. This experimental study was aimed to quantify the effect of JLE on in vivo knee kinematics in patients with bicruciate retaining (BCR) TKA during strenuous activities. Thirty unilateral BCR TKA patients were evaluated during single-leg deep lunge and sit-to-stand using a validated combined computer tomography and dual fluoroscopic imaging system. Correlation analysis was performed to quantify any correlations between JLE and in vivo kinematics, as well as PROMS. There was a significant negative correlation between JLE and maximum flexion angle during single-leg deep lunge (ρ = -0.34, p = 0.02), maximum varus joint angles during single-leg deep lunge (ρ = -0.37, p = 0.04), and sit-to-stand (ρ = -0.29, p = 0.05). There was a significant negative correlation between JLE and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (ρ = -0.39, p = 0.01) and knee disability and osteoarthritis outcome score physical function (KOOS-PS; ρ = -0.33, p = 0.03). The JLE that yields a significant loss in PROMS and maximum flexion angles were 2.6 and 2.3 mm, respectively. There was a linear negative correlation of JLE with both in vivo knee kinematics and PROMS, with changes in JLE of greater than 2.6 and 2.3 mm, leading to a clinically significant loss in PROMS and maximum flexion angles, respectively, suggesting an increased need to improve surgical precision to optimize patient outcomes following BCR TKA.

Asymmetrical tibial polyethylene geometry-cruciate retaining total knee arthroplasty does not fully restore in-vivo articular contact kinematics during strenuous activities.

PURPOSE: A new CR TKA design with concave medial and convex lateral tibial polyethylene bearing components was introduced recently to improve functional outcomes. This study aimed to investigate in-vivo articular contact kinematics in unilateral asymmetrical tibial polyethylene geometry CR TKA patients during strenuous knee flexion activities. METHODS: Fifteen unilateral CR TKA patients (68.4 ± 5.8 years; 6 male/9 female) were evaluated for both knees during sit-to-stand, single-leg deep lunges and step-ups using validated combined computer tomography and dual fluoroscopic imaging system. Medial and lateral condylar contact positions were quantified during weight-bearing flexion activities. The Wilcoxon signed-rank test was performed to determine if there is a significant difference in articular contact kinematics during strenuous flexion activities between CR TKA and the non-operated knees. RESULTS: Contact excursions of the lateral condyle in CR TKAs were significantly more anteriorly located than the contralateral non-operated knee during sit-to-stand (3.7 ± 4.8 mm vs - 7.8 ± 4.3 mm) and step-ups (- 1.5 ± 3.2 mm vs - 6.3 ± 5.8 mm). Contact excursions of the lateral condyle in CR TKAs were significantly less laterally located than the contralateral non-operated knee during sit-to-stand (21.4 ± 2.8 mm vs 24.5 ± 4.7 mm) and single-leg deep lunges (22.6 ± 4.4 mm vs 26.2 ± 5.7 mm, p < 0.05). Lateral condyle posterior rollback was not fully restored in CR TKA patients during sit-to-stand (9.8 ± 6.7 mm vs 12.9 ± 8.3 mm) and step-ups (8.1 ± 4.8 mm vs 12.2 ± 6.4 mm). Lateral pivoting patterns were observed in 80%, 73% and 69% of patients during sit-to-stand, step-ups and single-leg deep lunges respectively. CONCLUSION: Although lateral femoral rollback and lateral pivoting patterns were observed during strenuous functional daily activities, asymmetric contact kinematics still persisted in unilateral CR TKA patients. This suggests the specific investigated contemporary asymmetrical tibial polyethylene geometry CR TKA design evaluated in this study does not fully replicate healthy knee contact kinematics during strenuous functional daily activities. LEVEL OF EVIDENCE: III.

Knee Arthroscopy Prior to Revision TKA Is Associated with Increased Re-Revision for Stiffness.

This is an experimental study. As knee arthroscopy may be used as a suitable temporizing alternative prior to revision surgery, knee arthroscopy potentially may be a risk factor for subsequent adverse outcomes after revision total knee arthroplasty (TKA). This study aimed to evaluate the impact of prior knee arthroscopy on outcomes of subsequent TKA revision surgery. We identified 1,689 consecutive patients who underwent revision TKA: (1) patients with no prior knee arthroscopy (n = 1,549) and (2) patients with knee arthroscopy prior to revision TKA (n = 140). A control group of matched revision TKA patients who did not undergo prior knee arthroscopy was identified (700 patients), using one-to-five matching. Matched patients with prior knee arthroscopy demonstrated an increased likelihood of requiring re-revision (odds ratio [OR], 2.06, p < 0.001), particularly for stiffness (OR, 2.72, p < 0.02) compared with patients who underwent revision TKA without prior knee arthroscopy. Knee arthroscopy demonstrated a time-dependent impact on revision TKA outcomes, with an increased likelihood of requiring re-revision for patients who underwent knee arthroscopy within 6 months prior to revision TKA compared with patients who underwent knee arthroscopy within 6 to 12 months prior to revision TKA (OR, 3.16, p < 0.04). This cohort matched study shows that patients who had prior knee arthroscopy demonstrated a significantly higher likelihood of requiring re-revision compared with patients who underwent revision TKA without prior knee arthroscopy. Additionally, there was a significant increased likelihood in requiring re-revision for patients who had prior knee arthroscopy within 6 months. This provides clinically useful information for counseling of patients who are considering temporizing their symptoms with knee arthroscopy prior to revision TKA.

Preoperative Serum C-Reactive Protein/Albumin Ratio Is a Predictor of Complications After Single-stage Revision for the Treatment of Periprosthetic Joint Infection.

BACKGROUND: The C-reactive protein/albumin ratio (CAR) is a marker of inflammation that has been associated with negative outcomes in the general surgery. This study investigates the potential association of preoperative CAR with postoperative complications and readmission rates in the treatment of patients with single-stage revision total joint arthroplasty for periprosthetic joint infection. METHODS: A total of 213 consecutive patients who had undergone single-stage revision for total joint arthroplasty with the preoperative diagnosis of periprosthetic joint infection and preoperative C-reactive protein and albumin values were included. The area under receiver operating characteristic curves was calculated to evaluate the CAR as a predictive value for the complications. RESULTS: Significant differences between the mean CAR were found for patients with 30- and 60-day readmissions and reinfection (P < 0.01). CAR combined with serum and synovial fluid markers demonstrated significantly higher sensitivities and specificities for the prediction of 30-day (total knee arthroplasty [TKA]: 94%; 95%; total hip arthroplasty [THA]: 91%; 96%) and 60-day readmissions (THA: 94%; 95%; TKA: 92%; 96%) and reinfections (TKA: 94%; 95%; THA: 87%; 96%), when compared with only serum and synovial fluid markers combined (83%; 84%; 85%; 87%; 85%; 88%; P <0.01). DISCUSSION: High preoperative CAR, when combined with serum and synovial fluid markers, was associated with increased risk of reinfection and 30- and 60-day readmissions, suggesting that preoperative CAR is a clinically useful predictor for postoperative complications in patients with periprosthetic hip and knee joint infections.

Outcomes of Tourniquet-Less Revision Total Knee Arthroplasty: A Matched Cohort Analysis.

INTRODUCTION: A tourniquet is routinely used in total knee arthroplasty (TKA) to limit perioperative blood loss and increase the visibility of the surgeon's field of view. This study aims to evaluate the postoperative clinical outcomes and complications associated with tourniquet use in revision TKA. METHODS: We conducted a retrospective review of 1,904 consecutive patients who underwent revision TKA. Propensity score-based matching was done to adjust for baseline differences in patient demographics and procedure details. RESULTS: Propensity score matching resulted in a cohort of 548 revision total joint arthroplasty patients, 274 (50.0%) of whom were tourniquet patients matched to 274 (50.0%) tourniquet-less patients. Multivariate regression analyses demonstrated that, compared with the tourniquet-less cohort, the tourniquet cohort had significantly less intraoperative (413.7 to 353.2 mL, P < 0.01) and total perioperative (1,548.7 to 1,417.8 mL, P < 0.01) blood loss. However, no significant differences were present in total perioperative (8.4%, 6.6%, P = 0.43) transfusion rates. The tourniquet cohort had increased length of stay (3.2 to 3.7 days, P < 0.001) and 30-day readmissions (P = 0.04). DISCUSSION: This study demonstrated that although omitting the tourniquet in revision TKA leads to markedly increased perioperative blood loss, notable differences in perioperative transfusion rates were not observed. Furthermore, revision TKA without tourniquet use was associated with reduced postoperative length of stay, 30-day readmissions, and increased range of flexion.

Comparison of patient reported outcome measures after single versus two-stage revision for chronic infection of total hip arthroplasty: a retrospective propensity score matched cohort study.

INTRODUCTION: Two-stage revision is the current gold standard treatment for infected total hip arthroplasties (THA) with good clinical outcomes. Single-stage revision THA offers the advantage of only a single surgical intervention, potentially leading to improved functional outcomes. This study aimed to compare the differences in patient-reported outcome measures (PROMs) and complications between single and two-stage revision THA for chronic periprosthetic joint infection (PJI). METHODS: A total of 159 consecutive revision THA patients for chronic PJI with complete pre-and post-operative patient-reported outcome measures (PROM) was investigated. A total of 46 patients with single-stage revision THA was matched to 92 patients following two-stage revision THA using propensity score matching, yielding a total of 136 propensity score-matched patients for analysis. RESULTS: Single and two-stage revision THA improved PROM scores post-operatively, with significantly higher PROMs for single-stage revision THA (HOOS-PS: 50.7 vs 46.4, p = 0.04; Physical SF 10A: 42.1 vs 36.6, p < 0.001; PROMIS SF Physical: 41.4 vs 37.4, p < 0.001; PROMIS SF Mental: 52.8 vs 47.6, p < 0.001). There was no significant difference between both cohorts for reinfection rates (p = 0.81) and 90-day mortality rates (p = 1.0). CONCLUSION: This study found a demonstrable functional benefit of single-stage revision compared to two-stage revision for THA with chronic periprosthetic joint infection, suggesting that single-stage revision THA may provide an effective alternative to two-stage revision in selected patients with chronic PJI. LEVEL OF EVIDENCE: Level III, case-control retrospective analysis.

Outcomes and Risk Factors Associated With Failures of Debridement, Antibiotics, and Implant Retention in Patients With Acute Hematogenous Periprosthetic Joint Infection.

BACKGROUND: Acute hematogenous periprosthetic joint infections (PJI) accounts for 20% to 35% of all PJI cases. Treatment options include débridement, antibiotics, and implant retention (DAIR) or implant revision (single-stage/two-stage revision). Because the reported success rates of DAIR for acute PJIs as reported in the literature varies widely, this study aimed to investigate (1) the outcome of DAIR as revision surgery procedure and (2) the potential risk factors for treatment failure of DAIR in patients with acute hematogenous PJI. METHODS: We reviewed 106 consecutive cases of total joint arthroplasty patients who underwent DAIR for the diagnosis of acute hematogenous PJI. Outcomes of the cohort including infection free survival was investigated. Mean follow-up was 4.9 years. Demographics, case data, comorbidities, and extremity score were analyzed by univariate and multivariate regressions to identify risk factors for failure of DAIR. RESULTS: The failure rate of patients who underwent DAIR was 23.6% (25 of 106 patients). Univariate regression demonstrated that diabetes mellitus (P = 0.01) and polymicrobial infections (P < 0.01) are associated with failure of DAIR. Multivariate regression confirmed diabetes mellitus and polymicrobial infections as independent risk factors for failure of DAIR. DISCUSSION: Debridement, antibiotics, and implant retention may be a viable treatment option with moderate failure rates at the midterm follow-up in cases of acute hematogenous PJI. The study also identified diabetes mellitus and polymicrobial infections as independent risk factors for failure of DAIR. The findings of this study provide clinically useful information for surgeons in treatment of patients with acute hematogenous PJI.

One-stage revision is as effective as two-stage revision for chronic culture-negative periprosthetic joint infection after total hip and knee arthroplasty.

AIMS: Removal of infected components and culture-directed antibiotics are important for the successful treatment of chronic periprosthetic joint infection (PJI). However, as many as 27% of chronic PJI patients yield negative culture results. Although culture negativity has been thought of as a contraindication to one-stage revision, data supporting this assertion are limited. The aim of our study was to report on the clinical outcomes for one-stage and two-stage exchange arthroplasty performed in patients with chronic culture-negative PJI. METHODS: A total of 105 consecutive patients who underwent revision arthroplasty for chronic culture-negative PJI were retrospectively evaluated. One-stage revision arthroplasty was performed in 30 patients, while 75 patients underwent two-stage exchange, with a minimum of one year's follow-up. Reinfection, re-revision for septic and aseptic reasons, amputation, readmission, mortality, and length of stay were compared between the two treatment strategies. RESULTS: The patient demographic characteristics did not differ significantly between the groups. At a mean follow-up of 4.2 years, the treatment failure for reinfection for one-stage and two-stage revision was five (16.7%) and 15 patients (20.0%) (p = 0.691), and for septic re-revision was four (13.3%) and 11 patients (14.7%) (p = 0.863), respectively. No significant differences were observed between one-stage and two-stage revision for 30- 60- and 90-day readmissions (10.0% vs 8.0%; p = 0.714; 16.7% vs 9.3%; p = 0.325; and 26.7% vs 10.7%; p = 0.074), one-year mortality (3.3% vs 4.0%; p > 0.999), and amputation (3.3% vs 1.3%; p = 0.496). CONCLUSION: In this non-randomized study, one-stage revision arthroplasty demonstrated similar outcomes including reinfection, re-revision, and readmission rates for the treatment of chronic culture-negative PJI after TKA and THA compared to two-stage revision. This suggests culture negativity may not be a contraindication to one-stage revision arthroplasty for chronic culture-negative PJI in selected patients. Cite this article: Bone Joint J 2021;103-B(3):515-521.

Radiographic Risk Factors Associated With Adverse Local Tissue Reaction in Head-Neck Taper Corrosion of Primary Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: Adverse local tissue reactions (ALTRs) in metal-on-polyethylene (MoP) total hip arthroplasty (THA) with head-neck taper corrosion are multifactorial, involving implant and patient factors. This study aimed to identify any potential clinical risk factors associated with failed MoP THA due to head-neck taper corrosion. METHODS: A series of 146 MoP THA patients was investigated: (1) ALTR (n = 42) on metal artifact sequence MRI and (2) non-ALTR (n = 104). Both cohorts were compared regarding femoral neck shaft angle, acetabular implant orientation, component size, femoral head offset, measurement of medial and vertical femoral offsets, and femoral stem alloy. RESULTS: The occurrence of ALTR was associated with increased radiographic femoral stem offset (36.0 ± 7.7 mm versus 40.8 ± 7.3 mm, P = 0.008), increased femoral head offset (0.7 ± 3.4 versus 4.5 ± 3.7, P < 0.001), and the use of Ti-12Mo-6Zr-2Fe alloy stems (P = 0.041). The presence of ALTR was notably associated with higher chromium (2.0 versus 0.5 µg/L) and cobalt (7.4 versus 0.7 µg/L, P < 0.001). DISCUSSION: This study identified increased femoral head and stem offset and the use of Ti-12Mo-6Zr-2Fe alloy stems as risk factors for clinically relevant ALTR due to head-neck taper corrosion in MoP THA patients. This provides evidenced-based practical information for surgeons in identifying "at-risk" symptomatic MoP THA patients with head-neck taper corrosion for systematic risk stratification.