Porous Metal Augments Have Comparable Outcomes to Other Constructs for Severe Acetabular Bone Loss at a Mean Follow-up of 6.6-Years.

INTRODUCTION: 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 = 0.470) at a mean follow-up of 6.6 ± 3.4 years. Overall survivorship free from any revision surgery was comparable between the two groups (78.7 versus 79.5%, P = 0.720). There was also no difference in dislocation (5.7 versus 10.3%, P = 0.309) or periprosthetic joint infection rates (7.8 versus 10.3%, P = 0.623). In a subgroup analysis of patients who had pelvic discontinuity (n = 47), survivorship free from any revision surgery was comparable between the two groups (79.5 versus 72.2%, P = 0.543). CONCLUSION: Porous metal augments in the setting of severe acetabular bone loss demonstrated excellent survivorship at intermediate-term (mean 6.6-year) 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.

Serum and Synovial Markers in the Diagnosis of Periprosthetic Joint Infection of the Hip, Knee, and Shoulder: An Algorithmic Approach.

➤ No single test has demonstrated absolute accuracy for the diagnosis of periprosthetic joint infection (PJI).➤ Physicians rely on a combination of serological tests, synovial markers, and clinical findings plus clinical judgment to help to guide preoperative decision-making.➤ Several organizations have proposed criteria for the diagnosis of hip or knee PJI on which we now rely.➤ Given that shoulder arthroplasty has only recently become popular, it is possible that a shoulder-specific definition of PJI will be introduced in the coming years.➤ Although a number of serum and synovial markers have demonstrated high accuracy for the diagnosis of PJI of the hip and knee, further research is needed in order to identify markers that may be more suitable for the diagnosis of shoulder PJI and for the potential development and identification of specific serological tests as screening tools for PJI.

Minimally Invasive versus Open Transforaminal Lumbar Interbody Fusion in Obese Patients: A Propensity Score-Matched Study.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVES: This study aimed to compare the clinical outcomes of obese patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open TLIF. SUMMARY OF BACKGROUND DATA: The perioperative benefits of minimally invasive surgery in obese patients have been described. However, there is limited literature on the patient-reported outcomes (PROs), satisfaction and return to work following MIS-TLIF and open TLIF in this subgroup of patients. METHODS: Obese patients (BMI ≥30.0 kg/m2) who underwent a primary, one- to two-level open and MIS-TLIF were stratified and matched using propensity scoring. Operative time, length of stay and perioperative outcomes were recorded. Patient-reported outcomes (PROs) including Oswestry Disability Index, Short Form-36 Physical Component Score, Mental Component Score, Visual Analogue Scale for back pain and leg pain were compared at each postoperative time point. Achievement of minimal clinically important difference (MCID), patient satisfaction and return to work were also assessed. Revision procedures were recorded at mean 10±3.3 years follow-up. RESULTS: In total, 236 obese patients were included: 118 open TLIF and 118 MIS-TLIF. Length of stay was longer in the Open TLIF cohort and there was a trend towards a higher complication rate. However, there was no difference in operative time, transfusions or readmissions. Patients who underwent open TLIF reported worse ODI (P=0.043) and VAS leg pain at 2 years, although the latter did not reach statistical significance (P=0.095). Achievement of MCID for each PRO, patient satisfaction and return to work were also comparable. CONCLUSIONS: Obese patients who underwent MIS-TLIF had a shorter length of stay and improved functional disability at 2 years compared those who underwent open TLIF. However, a similar proportion achieved a clinical meaningful improvement. Patient satisfaction and return to work were also comparable at 2 years. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Direct Variable Cost Comparison of Endoscopic Versus Open Carpal Tunnel Release: A Time-Driven Activity-Based Costing Analysis.

INTRODUCTION: To improve the delivery of value-based health care, a deeper understanding of the cost drivers in hand surgery is warranted. Time-driven activity-based costing (TDABC) offers a more accurate estimation of resource utilization compared with top-down accounting methods. This study used TDABC to compare the facility costs of open carpal tunnel release (OCTR) and endoscopic carpal tunnel release (ECTR). METHODS: We identified 845 consecutive, unilateral carpal tunnel release (516 open, 329 endoscopic) surgeries performed at an orthopaedic specialty hospital between 2015 and 2021. Itemized facility costs were calculated using a TDABC algorithm. Patient demographics, comorbidities, surgical characteristics, and itemized costs were compared between OCTR and ECTR. Multivariate regression was used to determine the independent effect of endoscopic surgery on true facility costs. RESULTS: Total facility costs were $352 higher in ECTR compared with OCTR ($882 versus $530). ECTR cases had higher personnel costs ($499 versus $420), likely because of longer surgical time (15 versus 11 minutes) and total operating room time (35 versus 27 minutes). ECTR cases also had higher supply costs ($383 versus $110). Controlling for demographics and comorbidities, ECTR was associated with an increase in personnel costs of $35.74 (95% CI, $26.32 to $45.15), supply costs of $230.28 (95% CI, $205.17 to $255.39), and total facility costs of $265.99 (95% CI, $237.01 to $294.97) per case. DISCUSSION: Using TDABC, ECTR was 66% more costly to the facility compared with OCTR. To reduce the costs related to endoscopic surgery, efforts to decrease surgical time and negotiate lower ECTR-specific supply costs are warranted. LEVEL OF EVIDENCE: Economic and Decision Analysis Level II.

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.

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.

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.

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.

Long-Term Results of Minimally Invasive Transforaminal Lumbar Interbody Fusion in Elderly Patients: A 5-Year Follow-Up Study.

STUDY DESIGN: Retrospective review of prospective data. OBJECTIVES: Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) may be beneficial for elderly patients due to decreased surgical morbidity and faster postoperative recovery. This study compared the clinical and radiological outcomes of MIS-TLIF in elderly patients and younger controls at minimum 5-year follow-up. METHODS: There were 120 patients who underwent single-level MIS-TLIF for degenerative spondylolisthesis. Elderly patients (≥70 years; n = 30) and controls (<70 years; n = 90) were matched 1:3 for demographics, comorbidities and preoperative patient-reported outcomes (PROs). The Oswestry Disability Index (ODI), 36-Item Short-Form Physical (SF-36 PCS) and Mental Component Summary (SF-36 MCS), Visual Analogue Scale (VAS) back pain, and VAS leg pain were compared at 6 months, 2 years and 5 years. Radiographic fusion, adjacent segment degeneration (ASD) and revision rates were assessed at mean 7.2 ± 2.0 years. RESULTS: Elderly patients had longer length of stay (4.7 ± 5.8 vs 3.3 ± 1.4 days, P = .035) and more readmissions (10% vs 1%, P = .019), but there was no difference in operative time, transfusions, complications or discharge disposition. All PROs were comparable at 5 years and satisfaction rates were similar (93% elderly vs 91% controls, P = .703). The rates of radiographic fusion in the control group and elderly group were similar (94% vs 97%, P = .605), as were the rates of ASD (40% vs 33%, P = .503). There were 3 revisions (3.3%) in the control group (2 for ASD, 1 for screw loosening) but none in the elderly group (P = .311). CONCLUSIONS: Elderly patients undergoing MIS-TLIF achieved similar improvements in pain, disability and quality of life that were sustained at 5 years.Level of Evidence: Level III, retrospective cohort study.

Extracellular Vesicles: An Emerging Clinical Opportunity in Musculoskeletal Disease.

Extracellular vesicles (EVs) are important mediators of cell-to-cell communication in the extracellular space. These membranous nanoparticles carry various molecules, often referred to as "cargo," which are delivered to nearby target cells. In the past decade, developments in nanotechnology have allowed for various new laboratory techniques for the increased utilization of EVs in cellular and animal studies. Such techniques have evolved for the isolation, characterization, and delivery of EVs to biological tissues. This emerging technology has immense clinical potential for both diagnostic and therapeutic applications. Various EV cargo molecules, including DNA, RNA, and proteins, can act as pathological biomarkers. Furthermore, EVs derived from certain cell sources have shown therapeutic benefit in certain pathologies. In addition to their native therapeutic benefit, EVs can be engineered to carry and selectively deliver therapeutic agents. While EVs have gained increasing interest in various pathologies, few studies have compiled their clinical potential in musculoskeletal pathologies. To bridge this gap, we present an overview of EVs, introduce current laboratory preparation techniques, and outline the most recent literature regarding the potential therapeutic applications of EVs in musculoskeletal pathologies.

Two-Year Clinical and Radiologic Outcomes Following Surgical Treatment of Insertional Achilles Tendinopathy Using a Central Tendon-Splitting Approach.

BACKGROUND: If conservative treatment of insertional Achilles tendinopathy (IAT) fails, surgery is often considered. Various surgical approaches have been used including the central Achilles tendon splitting approach. This study aimed to report the 2-year clinical and radiologic outcomes after surgical treatment of IAT with a central tendon-splitting approach. METHODS: Seventy-five cases of IAT treated surgically via the open central tendon-splitting approach were analyzed. Clinical outcomes included the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, visual analog scale (VAS), 36-Item Short Form Health Survey (SF-36) physical (PCS) and mental (MCS) component summary scores, all measured at baseline and 6 and 24 months postoperatively. Radiologic parameters measured included the Fowler-Philip angle (FPA) and parallel pitch lines (PPL). RESULTS: Three patients had clinically significant wound issues but healed completely by 3 weeks. Mean AOFAS score improved from 45.63 preoperatively to 94.71 at 24 months. Mean VAS score improved from 6.73 preoperatively to 0.55, mean SF-36 PCS from 35.98 to 48.74, and mean SF-36 MCS from 53.04 to 55.43 at 24 months. Satisfaction at 2 years was 94.3%. Mean FPA decreased from 62.0 degrees preoperatively to 34.0 degrees postoperatively. PPL was positive in 82.7% (62 of 75) of cases preoperatively, decreasing to 1.3% (1 of 75) postoperatively. Increasing age and higher preoperative VAS and SF-36 MCS scores were significantly associated with improvements in postoperative AOFAS, SF-36 PCS, and MCS scores. CONCLUSION: Surgical treatment of IAT via the central tendon-splitting approach achieved substantial improvements in all patient-reported outcome measures measured. These excellent clinical outcomes continued to show improvement 2 years postoperatively. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Determinants of High Facility Costs in Total Joint Arthroplasty Patients: A Time-driven Activity-based Costing Analysis.

INTRODUCTION: Although several studies identify risk factors for high-cost patients in an episode of care for total hip (THA) and knee arthroplasty (TKA), few have looked at cost outliers from a facility perspective. The purpose of this study was to use time-driven activity-based costing (TDABC) to identify characteristics of high-cost patients. METHODS: We reviewed a consecutive series of primary THA and TKA patients by 22 different surgeons at two hospitals between 2015 and 2020. Facility costs were calculated using a TDABC algorithm for their entire hospital stay. Patients in the top decile of costs were considered to be high-cost patients. Multivariate regression was done to identify independent patient factors that predicted high costs. RESULTS: Of the 8,647 patients we identified, 60.5% underwent THA and 39.5% underwent TKA. Implant purchase price accounted for 49.5% of total inpatient costs (mean $2,880), followed by intraoperative (15.9%, mean $925) and postoperative personnel costs (16.8%, mean $980). Implant price demonstrated the highest variation between high-cost and low-cost groups (4.4 times). Patient-related factors associated with high costs were female sex (OR = 1.332), Hispanic ethnicity (OR = 1.409), American Society of Anesthesiology score (OR = 1.658), need for transfusion (OR = 2.008), and lower preoperative HOOS/KOOS Jr (OR = 1.009). CONCLUSION: This study identifies several variables for patients at risk to have high facility costs after primary THA and TKA. From the hospital's perspective, efforts to reduce implant purchase prices may translate into substantial cost savings. At the patient level, multidisciplinary initiatives to optimize medical comorbidities, decrease transfusion risk, and control medication expenses in high-risk patients may narrow the existing variation in costs.

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.

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.

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.

Hyponatremia Is an Overlooked Sign of Trouble Following Total Joint Arthroplasty.

BACKGROUND: Hyponatremia is a common electrolyte abnormality in arthroplasty patients. This issue, underrecognized by surgeons, can impact the postoperative course of patients. There are, however, little data on the implications of sodium disturbances following total joint arthroplasty (TJA). The primary aims of this study were to (1) report the rate of hyponatremia following TJA, and (2) examine the impact of hyponatremia on the perioperative course of TJA patients. METHODS: This was a retrospective analysis of 3,071 primary and revision TJAs performed between 2015 and 2017. Based on preoperative and postoperative sodium values (pre-post), patients were classified into 4 groups: normonatremic-normonatremic (Group 1), normonatremic-hyponatremic (Group 2), hyponatremic-normonatremic (Group 3), and hyponatremic-hyponatremic (Group 4). Primary end points were length of stay (LOS), postoperative discharge, in-hospital complications, and 90-day readmissions. RESULTS: The distribution of cases was 84.6% Group 1, 9.4% Group 2, 2.1% Group 3, and 3.8% Group 4. Overall, 13.2% of patients had hyponatremia after TJA. Older age, hip arthroplasty, general anesthesia, higher Charlson Comorbidity Index, congestive heart failure, revision surgery, and history of stroke, liver disease, and chronic kidney disease were risk factors for postoperative hyponatremia. Patients with postoperative hyponatremia (Groups 2 and 4) had greater likelihoods of having a 90-day complication and non-home discharge and greater LOS. CONCLUSIONS: Postoperative hyponatremia was a relatively common occurrence in patients undergoing TJA, and was associated with greater LOS, complications, and non-home discharge. Surgeons should identify patients at risk for developing sodium abnormalities in order to optimize these patients and avoid increased resource utilization. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Plasma D-Dimer Is Noninferior to Serum C-Reactive Protein in the Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: No single test has demonstrated absolute accuracy in the diagnosis of periprosthetic joint infection (PJI). Serological markers are often used as screening tools in the workup of patients with suspected PJI. This study aimed to determine the diagnostic utility of plasma D-dimer for PJI in a variety of clinical scenarios. METHODS: This prospective study enrolled 502 patients undergoing revision hip or knee arthroplasty. PJI was defined per a modified version of the 2018 International Consensus Meeting (ICM) criteria. Plasma D-dimer, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen were measured preoperatively. Receiver operating characteristic curves were used to assess the utility of each biomarker in the diagnosis of PJI. Pairwise comparison with Bonferroni correction was performed to determine whether the differences in areas under the curve (AUCs) between the markers were significant. RESULTS: Of the 412 patients included, 317 (76.9%) did not have an infection (aseptic group) and 95 (23.1%) had an infection (PJI group). 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 > 0.05). When examining the performance of the different inflammatory markers in diagnosing infection caused by indolent organisms, D-dimer demonstrated the highest sensitivity at 93.8%. CONCLUSIONS: We found that plasma D-dimer was noninferior to serum CRP and ESR in the diagnosis of PJI and may be a useful adjunct when screening patients undergoing revision total joint arthroplasty. LEVEL OF EVIDENCE: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence.

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.