Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag.

BACKGROUND: Extensor mechanism disruption is a devastating complication after TKA. Extensor mechanism reconstruction can be performed using an allograft or synthetic mesh. Recent studies have disagreed about the durability of these reconstructions. Evaluating a larger series of reconstructions that use current popular techniques and principles provides information to guide patient and surgeon expectations while bringing to light the potential fate of patients who experience an infection postoperatively. QUESTIONS/PURPOSES: (1) What was the 5-year survival free of repeat revision surgery or persistent extensor lag of more than 30° after allograft or synthetic mesh reconstruction of extensor mechanism disruptions after TKA, and did this differ between techniques? (2) What was the 5-year survival free of infection after allograft or mesh reconstruction, and what proportion of those patients experienced a secondary severe complication (arthrodesis or amputation)? METHODS: Between April 2008 and December 2020, 123 patients underwent extensor mechanism reconstruction after TKA at one center. Of those, 37% (45) were lost to follow-up before 2 years, had not been seen in the past 5 years, did not reach a study endpoint (repeat revision or extensor lag > 30°) before that time, or underwent primary repair and thus could not be analyzed, leaving 63% (78) for analysis here. During the study period, we considered extensor mechanism surgery when acute or chronic disruption of the patellar or quadriceps tendon was present or there was a fracture of the patella resulting in extensor lag. The decision to use either mesh or an allograft largely depended on surgeon experience and familiarity with either technique. We collected patient demographics, operative details (location of disruption and presence of a hinged prosthesis), subsequent periprosthetic joint infection (PJI), and postoperative SF-12 and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, scores. We used Kaplan-Meier survivorship analysis, with endpoints of extensor lag more than 30° or revision of the reconstruction and PJI. The mean follow-up duration was 5.3 ± 3.2 years. RESULTS: Survivorship free from revision or recurrent extensor lag was 54% (95% CI 44% to 66%) at 5 years. There was no difference between those undergoing reconstruction with allografts and those with mesh in terms of survivorship free from those endpoints at that timepoint (52% [95% CI 40% to 68%] versus 57% [95 CI% 41 to 78%]; p = 0.99). Survivorship free from PJI was 81% (95% CI 73% to 90%) at 2 years. There was no difference between those with allografts and those with mesh in terms of survivorship free from PJI at that timepoint (79% [95% CI 69% to 92%] versus 83% [95% CI 71% to 98%]; p = 0.75). Of the 17 patients who experienced PJI, four ultimately underwent arthrodesis and three more underwent transfemoral amputation. CONCLUSION: Allograft and synthetic mesh reconstructions commonly left patients with persistent limb dysfunction, while several patients had PJI and some underwent salvage procedures. Although improvements have been made with regard to treating extensor mechanism disruptions, patients and surgeons should be well aware of the potential adverse outcomes when determining management and use these findings to conduct risk-benefit analyses. There is a need for future studies to identify protocols that improve the durability of reconstructions and to determine whether interventions such as prolonged prophylactic antibiotic therapy have a role in minimizing the risk of PJI. LEVEL OF EVIDENCE: Level III, therapeutic study.

Direct Variable Cost Comparison of Monitored Anesthesia Care Versus Wide Awake Local Anesthesia No Tournique Carpal Tunnel Release: A Time-Driven Activity-Based Costing Analysis.

PURPOSE: Time-driven activity-based costing (TDABC) provides a more accurate and granular estimation of direct variable costs compared with traditional accounting methods. This study used TDABC to quantitatively compare the same-day facility costs of open carpal tunnel release (CTR) performed under monitored anesthesia care (MAC) versus wide awake local anesthesia no tourniquet (WALANT). METHODS: We retrospectively identified 474 unilateral CTR (182 MAC and 292 WALANT) performed at an orthopedic specialty hospital between 2015 and 2021. Itemized facility costs were calculated using a TDABC algorithm. Patient demographics, surgical characteristics, and itemized costs were compared between those treated under MAC (MAC-CTR) and WALANT (WALANT-CTR). Multivariable regression was performed to determine the independent effect of MAC on true facility costs. RESULTS: Total facility costs were $170 higher in MAC-CTR compared with WALANT-CTR ($652 vs $482). Monitored anesthesia care-CTR cases had higher personnel costs ($537 vs $394), likely because of higher surgery personnel ($303 vs $185) and postanesthesia care unit personnel costs ($117 vs $95). Monitored anesthesia care-CTR cases also had higher supply costs ($119 vs $81). When controlling for demographics and comorbidities, MAC-CTR was independently associated with an increase in personnel costs by $150.65 (95% CI, $131.09-$170.21), supply costs by $24.99 (95% CI, $9.40-$40.58), and total facility costs by $175.66 (95% CI, $150.18-$201.09) per case. CONCLUSIONS: Using TDABC, MAC-CTR was found to be 35% more costly to the facility compared with WALANT-CTR. Notably, WALANT-CTR facility costs presented here do not include additional cost savings from anesthesiologist service fees or preoperative laboratory clearance required for MAC-CTR surgeries. To reduce costs related to CTR surgery, greater efforts should be made to reduce the number of intraoperative personnel and maximize the use of WALANT-CTR in an outpatient setting. TYPE OF STUDY/LEVEL OF EVIDENCE: Economic and Decision Analysis II.

Increased Risk of Postoperative Complications in Patients Who Have Obstructive Sleep Apnea Undergoing Total Joint Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: Obstructive sleep apnea (OSA) has been linked to multiple adverse health outcomes and postoperative complications. Despite the high prevalence of OSA in patients undergoing total joint arthroplasty (TJA), few studies have evaluated the postoperative course of OSA patients after joint arthroplasty surgery. METHODS: PubMed (MEDLINE) and Scopus (EMBASE, MEDLINE, and COMPENDEX) were used to conduct a systematic review of articles from inception to July 2023. Primary studies comparing postoperative outcomes following TJA between patients who had and did not have OSA were included. Postoperative medical complications, utilization of critical care, hospital stay, and mortality data were extracted. Descriptive statistics and random-effects meta-analysis models were used to analyze the available data. Included studies were evaluated for methodological risks of bias using the risk of bias in non-randomized studies of interventions. This review was registered on the International Prospective Register of Systematic Reviews (ID: CRD42023447610). RESULTS: There were 7 studies with a total of 20,977 patients (9,425 hip; 11,137 knee; 415 hip or knee) that were included. Pulmonary complications were most frequently studied, followed by thromboembolic events. Cardiac, gastrointestinal, hematologic, genitourinary, and delirium events were also reported across studies. Meta-analysis revealed that OSA patients had 4-fold increased odds of overall medical complications (OR [odds ratio], 4.23; 95% confidence interval (CI), 2.97 to 6.04; P < .001; I2 = 0%), 4-fold increased odds of pulmonary complications (OR, 4.31; 95% CI, 2.82 to 6.60; P < .001; I2 = 0%), 2-fold increased odds of thromboembolic complications (OR, 1.92; 95% CI, 1.22 to 3.03; P = .005; I2 = 9%), and 4-fold increased odds of delirium (OR, 3.94; 95% CI, 1.72 to 9.04; P = .001; I2 = 0%). CONCLUSIONS: A significant association was found between OSA and overall medical, pulmonary, and thromboembolic complications. These patients also had a higher incidence of postoperative delirium. The present findings underscore the need for comprehensive perioperative strategies to mitigate these risks in OSA patients who elect to undergo TJA.

Weighing the Impact: The Influence of Body Mass Index on Facility Costs in Total Joint Arthroplasty.

BACKGROUND: Using time-driven activity-based costing (TDABC), a novel cost calculation method that more accurately reflects true resource utilization in health care, we sought to compare the total facility costs across different body mass index (BMI) groups following total joint arthroplasty (TJA). METHODS: The study consisted of 13,806 TJAs (7,340 total knee arthroplasties [TKAs] and 6,466 total hip arthroplasties [THAs]) performed between 2019 and 2023. The TDABC data from an analytics platform was employed to depict total facility costs, comprising personnel and supply costs. For the analysis, patients were stratified into four BMI categories: <30, 30 to <35, 35 to <40, and ≥40. Multivariable regression was used to determine the independent effect of BMI on facility costs. RESULTS: When indexed to patients who had BMI <30, elevated BMI categories (30 to <35, 35 to <40, and ≥40) were associated with higher total personnel costs (TKA 1.03x versus 1.07x versus 1.13x, P < .001; THA 1.00x versus 1.08x versus 1.08x, P < .001), and total supply costs (TKA 1.01x versus 1.04x versus 1.04x, P < .001; THA 1.01x versus 1.02x versus 1.03x, P = .007). Total facility costs in TJAs were significantly greater in higher BMI categories (TKA 1.02x versus 1.05x versus 1.08x, P < .001; THA 1.01x versus 1.05x versus 1.05x, P < .001). Notably, when incorporating adjustments for demographics and comorbidities, BMI values of 35, 40, and 45 relative to BMI of 25, exhibit a significant association with a 2, 3, and 5% increase in total facility cost for TKAs and a 3, 5, and 7% increase for THAs. CONCLUSIONS: Using TDABC methodology, this study found that overall facility costs of TJAs increase with BMI. The present study provides patient-level cost insights, indicating the potential need for reassessment of physician compensation models in this population. Further studies may facilitate the development of risk-adjusted procedural codes and compensation models for public and private payors. LEVEL OF EVIDENCE: Level IV, economic and decision analyses.

High Incidence of Acute Kidney Injury Following Antibiotic-Loaded Spacer Insertion for Periprosthetic Joint Infection: An Updated Review of the Literature.

BACKGROUND: The use of antibiotic-impregnated cement during 2-stage revision arthroplasty for periprosthetic joint infection poses a risk of renal complications following spacer insertion. This systematic review aimed to investigate the rate of acute kidney injury (AKI) following antibiotic-loaded spacer insertion and to identify risk factors associated with this complication. METHODS: A systematic review was performed using PubMed, Cochrane Central, and Scopus databases. All clinical studies that documented renal complications following antibiotic-loaded spacer insertion for periprosthetic knee (total knee arthroplasty [TKA]) or hip (total hip arthroplasty [THA]) infection were included. Articles that combined THA and TKA outcomes were also included and labeled "THA + TKA." Descriptive statistics were analyzed when data were available. RESULTS: There were 24 studies (9 THA, 7 TKA, 8 THA + TKA) included. The mean incidences of spacer-related AKI across THA, TKA, and THA + TKA cohorts were 4.2 (range, 0 to 10%), 14 (range, 0 to 19%), and 27% (range, 0 to 35%), respectively. The most common patient-related risk factors for AKI were underlying chronic kidney disease or high baseline creatinine, low preoperative hemoglobin, and blood transfusion requirement. Spacer-related risk factors included high antibiotic dosage (>3.6 g/cement batch) and antibiotic type. While most recovered without complication, select patients required hemodialysis for acute management (2 THA, 18 THA + TKA) and/or developed chronic kidney disease (8 TKA, 8 THA). CONCLUSION: The rate of AKI following spacer insertion was high and likely under-reported in the literature. Surgeons should be cognizant of this devastating complication and should closely monitor at-risk patients for AKI following antibiotic-loaded spacer insertion.

Prior Authorization Leads to Administrative Burden and Delays in Treatment in Primary Total Joint Arthroplasty Patients.

BACKGROUND: The prior authorization (PA) process is often criticized by physicians due to increased administrative burden and unnecessary delays in treatment. The effects of PA policies on total hip arthroplasty (THA) and total knee arthroplasty (TKA) have not been well described. The purpose of this study was to analyze the use of PA in a high-volume orthopaedic practice across 4 states. METHODS: We prospectively collected data on 28,725 primary THAs and TKAs performed at our institution between 2020 and 2023. Data collected included patient demographics, payer approval or denial, time to approval or denial, the number of initial denials, the number of peer-to-peer (P2P) or addenda, and the reasons for denial. RESULTS: Seven thousand five hundred twenty eight (56.4%) patients undergoing THA and 8,283 (54%) patients undergoing TKA required PA, with a mean time to approval of 26.3 ± 34.6 and 33.7 ± 41.5 days, respectively. Addenda were requested in 608 of 7,528 (4.6%) THA patients and 737 of 8,283 (8.9%) TKA patients. From a total of 312 (4.1%) THA patients who had an initial denial, a P2P was requested for 50 (0.7%) patients, and only 27 (0.4%) were upheld after the PA process. From a total of 509 (6.1%) TKA patients who had an initial denial, a P2P was requested for 55 (0.7%) patients, and only 26 (0.3%) were upheld after the PA process. The mean time to denial in the THA group was 64.7 ± 83.5, and the most common reasons for denial were poor clinical documentation (25.9%) and lack of coverage (25.9%). The mean time to denial in the TKA group was 63.4 ± 103.9 days, and the most common reason for denial was not specified by the payer (46.1%). CONCLUSIONS: The use of PA to approve elective THA and TKA led to increased surgical waiting times and a high administrative burden for surgeons and healthcare staff.

Fix or Replace? Comparable Outcomes with Internal Fixation and Distal Femoral Replacement for Periprosthetic Fractures above Total Knee Arthroplasty.

INTRODUCTION: The optimal treatment for periprosthetic fracture (PPfx) around total knee arthroplasty (TKA) remains a topic of debate. Due to its low incidence, comparative studies analyzing arthroplasty and fixation are lacking in the literature. The purpose of this study was to compare the outcomes of distal femoral replacement (DFR) and open reduction and internal fixation (ORIF) for distal femur PPfx. METHODS: We reviewed a consecutive series of 99 patients who underwent DFR (n = 54) or ORIF (n = 45) for distal femur PPfx. The indications for DFR were reviewed. Fractures were classified based on their relation to the implant using the Su classification. The primary outcome was re-revision, while secondary endpoints included inpatient complications, mortality within the first year, and mechanical complications such as loosening and non-union. RESULTS: Type 2 fractures were the most prevalent type in both groups (DFR 37 versus ORIF 48.9%), while Type 1 fractures were more commonly treated with ORIF (35.6 versus 16.7%) and Type 3 with DFR (46.3 versus 15.6%) (P = 0.003). The preferred techniques in the ORIF group were plate osteosynthesis (66.7%) and retrograde nailing (31.1%). At a mean follow-up of 4.2 years (range, 1 to 14.1), DFR and ORIF did not demonstrate any difference in revision rates (13 versus 24.4%, P = 0.140) or mortality (3.7 versus 4.4%, P = 0.887). However, more mechanical complications were noted in the ORIF group (22.2 versus 7.4%, P = 0.035). CONCLUSION: Both distal femoral replacement and open reduction and internal fixation have comparable revision rates, complications, and clinical outcomes when used in supracondylar periprosthetic distal femur fractures. Longer-term studies are needed to assess DFR survivorship as well as outcomes of newer trauma techniques such as nail-plate combinations.

Porous Metal Augments Have Comparable Outcomes to Other Constructs for Severe Acetabular Bone Loss at Mid-Term Follow-up.

BACKGROUND: Acetabular reconstruction options in the setting of severe bone loss remain limited, with few comparative studies published to date. The purpose of this study was to compare the outcomes of revision total hip arthroplasty (THA) for severe bone loss using porous metal augments to cup cage and triflange prostheses. METHODS: We reviewed a consecutive series of 180 patients who had Paprosky 3A or 3B acetabular defects and underwent revision THA. Patients treated with porous augments (n = 141) were compared with those who received cup cages or triflange constructs (n = 39). Failure of the acetabular construct was defined as undergoing acetabular revision surgery or radiographic evidence of loosening. RESULTS: There was no difference in acetabular component survivorship in patients undergoing revision THA with porous augments or a cage or triflange prosthesis (92.2 versus 87.2%, P = .470) at a mean follow-up of 6.6 ± 3.4 years. Overall, survivorship free from any revision surgery was comparable between the 2 groups (78.7 versus 79.5%, P = .720). There was also no difference in dislocation (5.7 versus 10.3%, P = .309) or periprosthetic joint infection rates (7.8 versus 10.3%, P = .623). In a subgroup analysis of patients who had pelvic discontinuity (n = 47), survivorship free from any revision surgery was comparable between the 2 groups (79.5 versus 72.2%, P = .543). CONCLUSIONS: Porous metal augments in the setting of severe acetabular bone loss demonstrated excellent survivorship at intermediate-term (mean 6.6 years follow-up, even in cases of pelvic discontinuity, with comparable outcomes to cup cages and triflanges. Instability and infection remain major causes of failure in this patient population, and long-term follow-up is needed.

Finding the Optimal Screening Test for Periprosthetic Joint Infection: A Prospective Study.

BACKGROUND: No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Serological markers are often used as screening tools to avoid unnecessary joint aspiration in cases with a low probability of infection. This study aimed to determine the utility of standard-of-care serological tests as a screening tool for PJI in patients undergoing revision arthroplasty. METHODS: This prospective study enrolled 502 patients undergoing revision hip or knee arthroplasty between May 2017 and August 2021. A PJI was defined using a modified definition of the 2018 International Consensus Meeting criteria. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. There were 82 patients undergoing reimplantation who were excluded. Additionally, 8 patients who had an inconclusive International Consensus Meeting score were also excluded. Of the 412 included patients, 317 (76.9%) underwent revision for aseptic failure, and 95 (23.1%) had PJI. Receiver operating characteristic curves were used to assess the diagnostic utility of each serological test. A pairwise comparison with Bonferroni correction was performed to determine whether the differences in areas under the curve (AUCs) between the tests were significant. Additional analyses were performed to find the threshold for each test that offered 100% sensitivity, allowing it to be the optimal screening test. RESULTS: All 4 serological markers, D-dimer (AUC 0.860, sensitivity 81.3%, specificity 81.7%), CRP (AUC 0.862, sensitivity 90.4%, specificity 70.0%), ESR (AUC 0.833, sensitivity 73.9%, specificity 85.2%), and fibrinogen (AUC 0.798, sensitivity 74.7%, specificity 75.4%), demonstrated comparable accuracy for the diagnosis of PJI (all P > .05). When maximizing sensitivity to 100%, D-dimer demonstrated the highest specificity (AUC 0.860, specificity 40.2%), outperforming ESR (AUC 0.833, specificity 3.3%), fibrinogen (AUC 0.798, specificity 2.3%), and CRP (AUC 0.862, specificity 0%). A plasma D-dimer level of ≥ 244 ng/mL was identified as the optimal cutoff for use as a screening test. CONCLUSIONS: Although plasma D-dimer demonstrated similar diagnostic accuracy as CRP, ESR, and fibrinogen, it outperformed all 3 aforementioned serological markers when used as a screening test for PJI. LEVEL OF EVIDENCE: Level II.

Outcomes of Metaphyseal Cones and Stem Fixation Following Rotating Hinge in Complex Primary and Revision Total Knee Arthroplasty.

BACKGROUND: Although hinged prostheses have been used successfully in complex revision total knee arthroplasty (TKA), concerns exist regarding early failure due to aseptic loosening and other mechanical complications. The use of metaphyseal cones and hybrid cement fixation have been studied in unlinked constrained primary or revision TKA, but their impact on the survivorship of hinged prostheses has yet to be investigated. METHODS: We identified a consecutive series of 164 hinged prostheses and collected data on demographics, indications, complications, and re-revisions in patients who had fully cemented versus hybrid stems, with and without metaphyseal cones. A multivariate analysis was performed to identify independent variables associated with re-revision as the primary end point. RESULTS: In total, 84 patients (51.2%) had fully cemented stems, and 80 patients (48.8%) had hybrid stems. Cones were used in 73 patients (44.5%). At a mean follow-up of 3.4 ± 2.2 years, 42 patients underwent re-revision (25.8%), most commonly for infection (12.2%), followed by loosening (6.7%) and periprosthetic fracture (3.7%). Patients who had fully cemented stems had lower re-revision rates than hybrid fixation constructs (19 versus 26%, P = .043). Using multivariable regression, a construct with hybrid fixation with cones (odds ratio = 2.39; P = .037) was an independent risk factor for failure. Utilization of cones alone did not have an effect on re-revision rates at 3.4-year follow-up. CONCLUSIONS: While we found no difference with the use of cones, patients undergoing revision TKA with a hinge prosthesis and fully cemented stems had better overall survivorship than hybrid stems.

UKA with a handheld robotic device results in greater surgeon physiological stress than conventional instrumentation.

PURPOSE: Poor ergonomics and acute stress can impair surgical performance and cause work-related injuries. Robotic assistance may optimize these psychophysiological factors during UKA. This study compared surgeon physiologic stress and ergonomics during robotic-assisted UKA (rUKA) and conventional UKA (cUKA). METHODS: Cardiorespiratory and postural data from a single surgeon were recorded during 30 UKAs, (15 rUKAs, 15 cUKAs). Heart rate (HR), HR variability, respiratory rate (RR), minute ventilation and calorie expenditure were used to measure surgical strain. Intraoperative ergonomics were assessed by measuring flexion/extension/rotation of the neck and lumbar spine, and shoulder abduction/adduction. RESULTS: Mean operative time was 32.0 ± 7 min for cUKA and 45.9 ± 9 min for rUKA (p < 0.001). Mean neck flexion was - 23.4° ± 13° for rUKA and - 49.1° ± 18 for cUKA (p < 0.001), while mean lumbar flexion was - 20.3° ± 30° for rUKA and - 0.4° ± 68° for cUKA (p = 0.313). Mean lumbar flexion was similar; however, a significantly greater percentage of time was spent in lumbar flexion > 20° during cUKA. Bilateral shoulder abduction was significantly higher for rUKA. Mean calorie expenditure was 154 cal for rUKA and 89.1 cal for cUKA (p < 0.001). Mean HR was also higher for rUKA (88.7 vs. 84.7, p = 0.019). HR variability was slightly lower for rUKA (12.4) than for cUKA (13.4), although this did not reach statistical significance (p = 0.056). No difference in RR or minute ventilation was observed. CONCLUSION: rUKA resulted in less neck flexion but increased shoulder abduction, heart rate, and energy expenditure. The theoretical ergonomic and physiologic advantages of robotic assistance using a handheld sculpting device were not realized in this study. LEVEL OF EVIDENCE: II.

Aseptic revision total knee arthroplasty outcomes were equivalent to patients' own pre-failure state but inferior to patients without revision.

PURPOSE: The purpose of this study was to (1) longitudinally compare the patient-reported outcome measures (PROMs) of the same patients who underwent primary TKA and revision TKA, and (2) compared the results of these revision TKA with a matched cohort of well-functioning primary TKA. The hypothesis was revision TKA could result in equivalent outcomes to patients' own primary TKA or the primary TKA of patients who did not require revision. METHODS: Prospectively collected data of 123 patients who underwent primary TKA and subsequently aseptic revision TKA ("revised group"), were matched using nearest-neighbor method to 123 well-functioning primary TKA that did not require revision ("control group"). Preoperative (prior to primary TKA), at time of failure (prior to revision TKA), postoperative 6-month and 2-year PROMs included Knee Society scores (KSS), Oxford Knee Score (OKS) and Short Form-36 (SF-36). Minimal clinically important difference (MCID) attainment was analyzed. Wilcoxon and McNemar's tests were used to compare outcomes within the revised group (primary vs revision), Mann-Whitney U test and Chi-Square test for the revised and control groups. RESULTS: The revised group had poorer KSS objective (p = 0.045), KSS functional (p < 0.001), OKS (p = 0.011) and SF-36 PCS (p < 0.001) at time of failure (prior to revision TKA), compared to their preoperative PROMs (prior to primary TKA). Revision TKA resulted in restoration of KSS objective, OKS and SF-36 PCS (NS) that were equivalent to their primary TKA, but poorer KSS functional (p < 0.050). Patients in the revised group had a lower proportion of MCID attainment in KSS objective (p = 0.014) and OKS (p < 0.001) at 2-year after primary TKA when compared to the control group. Revision TKA also led to poorer KSS objective, KSS functional and SF-36 PCS (p < 0.050) when compared to primary TKA of the control group. CONCLUSION: Outcomes following aseptic revision were equivalent to patients' own pre-failure state but inferior to patients with non-revised implants. An individualized approach toward goal setting and assessing adequacy of aseptic revision TKA can be adopted based on patients' pre-failure outcomes. LEVEL OF EVIDENCE: III.

The patient acceptable symptom state for the knee society score, oxford knee score and short form-36 following unicompartmental knee arthroplasty.

PURPOSE: The patient acceptable symptom state (PASS) is a target value on a patient-reported outcome measures (PROM) scale beyond which patients deem themselves to have attained an acceptable outcome. This study aimed to define the PASS thresholds for generic and knee-specific PROMs at 2 years after unicompartmental knee arthroplasty (UKA). METHODS: Prospectively collected data of 955 patients who underwent UKA for medial osteoarthritis at a single institution was reviewed. Patients were assessed preoperatively and 2 years postoperatively using the Knee Society Knee Score (KSKS), Function Score (KSFS), Oxford Knee Score (OKS), SF-36 Physical Component Score (PCS) and Mental Component Score (MCS). Responses to an anchor question assessing patients' overall rating of treatment results were dichotomized and used to determine if PASS was achieved. PASS thresholds for each PROM were selected based on the Youden index on a receiver operating characteristics (ROC) curve. Sensitivity analyses were performed for different subgroups (by age, gender, BMI), baseline score tertiles and an alternate definition of PASS. RESULTS: In total, 92.7% reported their current state as acceptable. The areas under the curve (AUC) for ROCs were 0.72-0.83, except for the SF-36 PCS (AUC 0.64), indicating good discriminative accuracy of the other PROMs. PASS thresholds were 85.5 for KSKS, 77.5 for KSFS, 41.5 for OKS, 49.9 for SF-36 PCS and 54.6 for SF-36 MCS. Sensitivity analyses revealed that the thresholds were robust. Patients who attained a PASS were at least 4-5 times more likely to be satisfied and have expectations fulfilled. CONCLUSION: PASS thresholds can be used to define treatment success in future outcome studies. At the individual level, they provide clinically relevant benchmarks for surgeons when assessing postoperative recovery. LEVEL OF EVIDENCE: III.

Identifying High Direct Variable Costs of Open Carpal Tunnel Release Patients Using Time-Driven Activity-Based Costing.

PURPOSE: To improve value in health care delivery, a deeper understanding of the cost drivers in hand surgery is necessary. Time-driven activity-based costing (TDABC) more accurately reflects true resource use compared with traditional accounting methods. This study used TDABC to explore the facility cost of carpal tunnel release and identify preoperative characteristics of high-cost patients. METHODS: Using TDABC, we calculated the facility costs of 516 consecutive patients undergoing open carpal tunnel release at an orthopedic specialty hospital between 2015 and 2021. Patients in the top decile cost were defined as high-cost patients. Multivariable logistic regression was used to determine preoperative characteristics (age, sex, body mass index, race, ethnicity, Elixhauser comorbidity index, American Society of Anesthesiology score, preoperative Disabilities of the Arm, Shoulder and Hand score, Short-Form 12, and anesthesia type) independently associated with high-cost patients. RESULTS: Surgery-related personnel costs were the main driver (38.0%) of total facility costs, followed by preoperative personnel costs (21.3%). There was a 1.8-fold variation in facility cost between patients in the 90th and 10th percentiles ($774.69 vs $431.35), with the widest cost variations belonging to medication costs ($17.67 vs $1.85; variation, 9.6-fold) and other supply costs ($213.56 vs $65.56; variation, 3.3-fold). Using multivariable regression, predictors of high cost were patient age and use of general anesthesia. Total facility costs correlated strongly with the total operating room time and incision to closure time. CONCLUSIONS: Efforts to decrease operating room time may translate into reduced personnel costs and greater cost savings. Multidisciplinary initiatives to control medication expenses for patients at risk of high costs may narrow the existing variation in costs. TYPE OF STUDY/LEVEL OF EVIDENCE: Economic and Decision Analysis II.

Does the Use of Tranexamic Acid in Patients Who Have Preoperative Coagulopathy Undergoing Total Joint Arthroplasty Normalize Their Risk of Complications? A Matched Equivalence Analysis.

BACKGROUND: While patients who have a preoperative coagulopathy have an increased risk of perioperative blood loss, tranexamic acid (TXA) has been shown to decrease the risk of complications in this subset. However, a direct comparison of the use of TXA in coagulopathic and noncoagulopathic patients has not been performed. In addition to comparing differences in decreases in hemoglobin, transfusions, and complications, this study examined whether the use of TXA in coagulopathic patients normalized the risk of blood loss relative to matched noncoagulopathic patients. METHODS: We performed a retrospective review of 230 patients who had a preoperative coagulopathy and underwent primary total joint arthroplasty (127 hips, 103 knees) from 2012 to 2019 and received TXA. Coagulopathy was defined as international normalized ratio >1.2, partial thromboplastin time >35 seconds, or platelet count <150,000/mL (mL). A matched comparison group of 689 patients who did not have a coagulopathy and received TXA was identified. A 2 1-sided test (TOST) analysis was performed to test for equivalence. Assuming a clinically relevant difference of 1 g/dL in postoperative decrease in hemoglobin, the equivalence margin was set as ±1 g/dL between the groups. RESULTS: When comparing coagulopathic and noncoagulopathic patients, total hip arthroplasty (THA) patients had no differences in hemoglobin, but had an increased reported estimated blood loss (243 versus 207 mL, P = .040) as well as an increased percent of patients requiring blood transfusions (11.8 versus 5.32%, P = .022). Total knee arthroplasty (TKA) patients had no differences in hemoglobin, estimated blood loss, or percent of patients requiring transfusion. There were no differences in medical or surgical complications for both groups for THA and TKA patients. Equivalence testing for both groups revealed statistical significance that THA and TKA coagulopathic patients receiving TXA had an equivalent risk of blood loss compared to noncoagulopathic patients receiving TXA. CONCLUSION: Coagulopathic patients receiving TXA and undergoing THA had an increased risk of receiving a transfusion; however, there were no differences in complications for both TKA and THA, as well as a normalized risk of blood loss when compared to noncoagulopathic patients. LEVEL OF EVIDENCE: III.

Should We Aim to Help Patients "Feel Better" or "Feel Good" After Total Hip Arthroplasty? Determining Factors Affecting the Achievement of the Minimal Clinically Important Difference and Patient Acceptable Symptom State.

BACKGROUND: Recent attempts have been made to use preoperative patient-reported outcome measure (PROM) thresholds as prior authorization criteria based on the assumption that patients who have higher baseline scores are less likely to achieve the minimal clinically important difference (MCID). This study aimed to identify factors affecting the achievement of MCID and patient acceptable symptom state (PASS) after total hip arthroplasty (THA), and to determine the overlap between the two outcomes. METHODS: We identified 3,581 primary, unilateral THAs performed at a single practice in 2015-2019. PROMs including Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and 12-item Short Form Health Survey were collected preoperatively and 1-year postoperatively. The likelihood of attaining PASS according to attainment of MCID was assessed. Multivariable regression was used to identify independent predictors of MCID and PASS. RESULTS: In total, 79.8% achieved MCID and 73.6% achieved PASS for HOOS-JR. Approximately 1 in 7 patients who achieved MCID did not eventually achieve PASS. Worse preoperative HOOS-JR (odd ratio 0.933) was associated with MCID attainment. Better preoperative HOOS-JR (odd ratio 1.015) was associated with PASS attainment. Men, lower body mass index, better American Society of Anesthesiologists score, and better preoperative 12-item Short Form Health Survey mental score were predictors of MCID and PASS. Age, race, ethnicity, Charlson Comorbidity Index, and smoking status were not significant predictors. CONCLUSION: Preoperative PROMs were associated with achieving MCID and PASS after THA, albeit in opposite directions. Clinicians should strive to help patients "feel better" and "feel good" after surgery. Preoperative PROMs should not solely be used to prioritize access to care.

Plasma D-Dimer Is a Promising Marker to Guide Timing of Reimplantation: A Prospective Cohort Study.

BACKGROUND: Two-stage exchange arthroplasty remains the preferred surgical treatment for chronic periprosthetic joint infection. Currently, there is no single reliable marker to determine the optimal timing for reimplantation. The purpose of this prospective study was to assess the diagnostic utility of plasma D-dimer and other serological markers in predicting successful control of infection following reimplantation. METHODS: This study enrolled 136 patients undergoing reimplantation arthroplasty between November 2016 and December 2020. Strict inclusion criteria were applied including the need for a two-week "antibiotic holiday" prior to reimplantation. A total of 114 patients were included in the final analysis. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. Treatment success was defined using the Musculoskeletal Infection Society Outcome-Reporting Tool. Receiver operating characteristic curves were used to assess the prognostic accuracy of each biomarker in predicting failure following reimplantation at a minimum 1-year follow-up. RESULTS: Treatment failure occurred in 33 patients (28.9%) at a mean follow-up of 3.2 years (range, 1.0 to 5.7). Median plasma D-dimer was significantly higher in the treatment failure group (1,604 versus 631 ng/mL, P < .001), whereas median CRP, ESR, and fibrinogen were not significantly different between the success and failure groups. Plasma D-dimer demonstrated the best diagnostic utility (area under the curve [AUC] 0.724, sensitivity 51.5%, specificity 92.6%), outperforming ESR (AUC 0.565, sensitivity 93.3%, specificity 22.5%), CRP (AUC 0.541, sensitivity 87.5%, specificity 26.3%), and fibrinogen (AUC 0.485, sensitivity 30.4%, specificity 80.0%). Plasma D-dimer level of ≥1,604 ng/mL was identified as the optimal cutoff that predicted failure following reimplantation. CONCLUSION: Plasma D-dimer was superior to serum ESR, CRP, and fibrinogen in predicting failure after the second stage of a two-stage exchange arthroplasty for periprosthetic joint infection. Based on the findings of this prospective study, plasma D-dimer may be a promising marker in assessing the control of infection in patients undergoing reimplantation surgery. LEVEL OF EVIDENCE: Level II.

The Ability of Robot-Assisted Total Knee Arthroplasty in Matching the Efficiency of Its Conventional Counterpart at an Orthopaedic Specialty Hospital.

BACKGROUND: Robot-assisted total knee arthroplasty (RA-TKA) has become a popular technology. Studies have investigated the learning curve for surgeons incorporating RA-TKA into practice, but less is known regarding the change in operative efficiency when introducing RA-TKA into a facility. The purpose of this study was to investigate the effects of RA-TKA on operative and turnover time at an orthopaedic specialty hospital. METHODS: A total of 148 cases (74 RA-TKA and 74 conventional TKA [C-TKA]) performed by 2 surgeons with previous robotic experience were identified following the introduction of RA-TKA at our facility. Patient demographics, comorbidities, and operative times (ie, wheels-in to incision, incision to closure, closure to wheels-out, and turnover time) were recorded. Cumulative summation analyses were used to investigate learning curves of factors extraneous to surgeon proficiency with RA-TKA. RESULTS: While RA-TKA had a slightly longer set up (3 minutes; range, 12-45), surgical (5 minutes; range, 33-118), and breakdown time (3 minutes; range, 2-7), there was no difference in turnover time between the groups. The learning curve for surgeon A was 6 robotic cases, whereas surgeon B demonstrated no learning curve. There was no identifiable learning curve for turnover time. CONCLUSION: There was a mean of 8 minutes of increased time required to perform a RA-TKA compared to C-TKA. However, these small increases for the RA-TKA group for set-up, surgical, and breakdown times are not likely to be clinically relevant compared to the C-TKA. It appears that the RA-TKA technology was able to be incorporated into this specialty hospital with minimal changes to surgical efficiency.

Patients Who Have Kellgren-Lawrence Grade 3 and 4 Osteoarthritis Benefit Equally From Total Knee Arthroplasty.

BACKGROUND: Recently, some payers have limited access to total knee arthroplasty (TKA) to patients who have Kellgren-Lawrence (KL) grade 4 osteoarthritis only. This study compared the outcomes of patients who have KL grade 3 and 4 osteoarthritis after TKA to determine if this new policy is justified. METHODS: This was a secondary analysis of a series originally established to collect outcomes for a single, cemented implant design. A total of 152 patients underwent primary, unilateral TKA at two centers from 2014 to 2016. Only patients who had KL grade 3 (n = 69) or 4 (n = 83) osteoarthritis were included. There was no difference in age, sex, American Society of Anesthesiologists score, or preoperative Knee Society Score (KSS) between the groups. Patients who had KL grade 4 disease had a higher body mass index. KSS and Forgotten Joint Score (FJS) were collected preoperatively and at 6 weeks, 6 months, 1 year, and 2 years postoperatively. Generalized linear models were used to compare outcomes. RESULTS: Controlling for demographics, improvements in KSS were comparable between the groups at all time points. There was no difference in KSS, FJS, and the proportion that achieved the patient acceptable symptom state for FJS at 2 years. CONCLUSION: Patients who had KL grade 3 and 4 osteoarthritis experienced similar improvement at all time points up to 2 years after primary TKA. There is no justification for payers to deny access to surgical treatment for patients who have KL grade 3 osteoarthritis and have otherwise failed nonoperative treatment.

Manipulation Under Anesthesia is Safe After Cementless Total Knee Arthroplasty: A Multicenter Study.

BACKGROUND: Cementless total knee arthroplasty (TKA) is thought to facilitate durable, biological fixation between the bone and implant. However, the 4-12 weeks required for osseointegration coincides with the optimal timeframe to perform a manipulation under anesthesia (MUA) if a patient develops postoperative stiffness. This study aims to determine the impact of early MUA on cementless fixation by comparing functional outcomes and survivorship of cementless and cemented TKAs. METHODS: A consecutive series of patients who underwent MUA for postoperative stiffness within 90 days of primary, unilateral TKA at 2 academic institutions between 2014 and 2018 were identified. Cases involving extensive hardware removal were excluded. Cementless TKAs undergoing MUA (n = 100) were propensity matched 1:1 to cemented TKAs undergoing MUA (n = 100) using age, gender, body mass index, and year of surgery. Both groups had comparable baseline Knee Injury and Osteoarthritis Outcome Scores (KOOS), Short Form (SF)-12 Physical, and SF-12 Mental scores. MUA-related complications as well as postoperative KOOS and SF-12 scores were compared. RESULTS: MUA-related complications were equivalently low in both groups (P = .324), with only 1 patella component dissociation in the cementless group. No tibial or femoral components acutely loosened in the perioperative period. Postoperative KOOS (P = .101) and SF-12 Mental scores (P = .380) were similar between groups. Six-year survivorship free from any revision after MUA was 98.0% in both groups (P = 1.000). CONCLUSION: Early postoperative MUA after cementless TKA was not associated with increased MUA-related complications or worse patient-reported outcomes compared to cemented TKA. Short-term survivorship was also comparable, suggesting high durability of the bone-implant interface.