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temporal dynamics at rest, but the overall dynamic patterns varied drastically across sub-networks. Graph-theory analysis identified the MD nucleus as a hub that connects subcortical and cortical nociceptive sub-networks. The S2-pIns connection joins the sensory and affective/cognitive sub-networks.Deuterium metabolic imaging (DMI) and hyperpolarized 13C-pyruvate MRI (13C-HPMRI) are two emerging methods for non-invasive and non-ionizing imaging of tissue metabolism. Imaging cerebral metabolism has potential applications in cancer, neurodegeneration, multiple sclerosis, traumatic brain injury, stroke, and inborn errors of metabolism. Here we directly compare these two non-invasive methods at 3 T for the first time in humans and show how they simultaneously probe both oxidative and non-oxidative metabolism. DMI was undertaken 1-2 h after oral administration of [6,6'-2H2]glucose, and 13C-MRI was performed immediately following intravenous injection of hyperpolarized [1-13C]pyruvate in ten and nine normal volunteers within each arm respectively. DMI was used to generate maps of deuterium-labelled water, glucose, lactate, and glutamate/glutamine (Glx) and the spectral separation demonstrated that DMI is feasible at 3 T. 13C-HPMRI generated maps of hyperpolarized carbon-13 labelled pyruvate, lactate, and bicarbonate. this website The ratio of 13C-lactate/13C-bicarbonate (mean 3.7 ± 1.2) acquired with 13C-HPMRI was higher than the equivalent 2H-lactate/2H-Glx ratio (mean 0.18 ± 0.09) acquired using DMI. These differences can be explained by the route of administering each probe, the timing of imaging after ingestion or injection, as well as the biological differences in cerebral uptake and cellular physiology between the two molecules. The results demonstrate these two metabolic imaging methods provide different yet complementary readouts of oxidative and reductive metabolism within a clinically feasible timescale. Furthermore, as DMI was undertaken at a clinical field strength within a ten-minute scan time, it demonstrates its potential as a routine clinical tool in the future.

Regulatory change has created a growing demand to decrease the hospital costs associated with primary total joint arthroplasty (TJA). Concurrently, the removal of lower extremity TJA from the in-patient only list has affected hospital reimbursement. The purpose of this study is to investigate trends in hospital revenue versus costs in primary TJA.

We retrospectively reviewed all patients who underwent primary TJA from June 2011 to May 2021 at our institution. Patient demographics, revenue, total cost, direct cost, and contribution margin were collected. Changes over time as a percentage of 2011 numbers were analyzed. Linear regression analysis was used to determine overall trend significance and develop projection models.

Total knee arthroplasty (TKA) insured by government-managed/Medicaid (GMM) plans showed a significant upward trend (P= .013) in total costs. Direct costs of TKA across all insurance providers (P=.001 and P < .001) and total hip arthroplasty (THA) for Medicare (P= .009) and GMM (P= .001) plans demonstrated significant upward trends. Despite this, 2011-2021 modeling found no significant change in contribution margin for TKA and THA covered under all insurance plans. However, models based on 2018-2021 financial data demonstrated a significant downward trend in contribution margin across Medicare (P < .001) and GMM (P < .001) insurers for both TKA and THA.

Physician-led innovation in cost-saving strategies has maintained contribution margin over the past decade. However, the increase in direct costs seen over the past few years could lead to negative contribution margins over time, if further efficiency and cost-saving measures are not developed.

Retrospective Cohort Study.

Retrospective Cohort Study.

When faced with a periprosthetic joint infection (PJI) following total knee arthroplasty, the treating surgeon must determine whether 2-stage revision or "liner exchange," aka debridement, antibiotics, exchange of the modular polyethylene liner, and retention of fixed implants (DAIR), offers the best balance of infection eradication versus treatment morbidity. We sought to determine septic re-revision risk following DAIR compared to initial 2-stage revision.

We conducted a cohort study using data from Kaiser Permanente's total joint replacement registry. Primary total knee arthroplasty patients who went on to have a PJI treated by DAIR or 2-stage revision were included (2005-2018). Propensity score-weighted Cox regression was used to evaluate risk for septic re-revision.

In total, 1,410 PJIs were included, 1,000 (70.9%) treated with DAIR. Applying propensity score weights, patients undergoing DAIR had a higher risk for septic re-revision compared to initial 2-stage procedures (hazard ratio 3.09, 95% CI 2.22-4.42). Of DAIR procedures, 150 failed (15%) and went on to subsequent 2-stage revision (DAIR-F). When compared to patients undergoing an initial 2-stage revision, we failed to observe a difference in septic re-revision risk following DAIR-F (hazard ratio 1.11, 95% CI 0.58-2.12).

Although DAIR had a higher risk of septic re-revision, we failed to observe a difference in risk following DAIR-F when compared to those who initially underwent 2-stage revision. Functional outcome, patient, and organism factors are important to consider when discussing PJI management options.

Level III.

Level III.

It remains unclear whether reimplantation of a patellar component during a two-stage revision for periprosthetic total knee arthroplasty infection (PJI) affects patient reported outcome measures (PROMs) or implant survivorship. The purpose of this study was to evaluate whether patellar resurfacing during reimplantation confers a functional benefit or increases implant survivorship after two-stage treatment for PJI.

Two-stage revisions for knee PJI performed by three surgeons at a single tertiary care center were reviewed retrospectively. All original patellar components and cement were removed during resection and the patella was resurfaced whenever feasible during reimplantation. PROMs, implant survivorship, and radiographic measurements (patellar tilt and displacement) were compared between knees reimplanted with a patellar component versus those without a patellar component.

A total of 103 patients met the inclusion criteria. Forty-three patients (41.7%) underwent reimplantation with, and 60 patients (58.3%) without a patellar component. At a mean follow-up of 33.5 months, there were no significant differences in patient demographics or PROMs between groups (P ≥ .156). No significant differences were found in the estimated Kaplan-Meier all-cause, aseptic, or septic survivorship between groups (P ≥ .342) at a maximum of 75 months follow-up. There was no significant difference in the change (pre-resection to post-reimplant) of patellar tilt (P= .504) or displacement (P= .097) between the groups.

Patellar resurfacing during knee reimplantation does not appear to meaningfully impact postoperative PROMs or survivorship. Given the risk of potential extensor mechanism complications with patellar resurfacing, surgeons may choose to leave the patella without an implant during total knee reimplantation and expect similar clinical outcomes.

Level III.

Level III.

The objective of this study was to investigate the impact of alignment and soft tissue release on patient outcomes following total knee arthroplasty (TKA).

In a multicenter study, soft tissue releases during TKA were prospectively documented in 330 robotic-assisted TKAs. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were captured postoperatively. Delphi analysis was used to determine inlier and outlier component alignment boundaries Tibia Coronal (TC) ±3°, Femur Coronal (FC) ±3°, Femoral Axial (FA) 3°Int-6°Ext, Hip-Knee-Ankle (HKA) 3°Val-4°Var, and Tibiofemoral Axial (TFA) 3°Int-6°Ext. Kruskal-Wallis analysis of variance tests were used to compare groups.

No significant differences were found between any individual or grouped inlier and outlier alignment criterion and KOOS at any timepoint. Outlier alignment frequencies were TC 0%, FC 12%, FA 8%, HKA 9%, TFA 8%, and Any 23%. Soft tissue releases were performed in 18% of cases. Knees with soft tissue releases reported significantly worse KOOS scores at 6M Symptoms (80.0 versus 75.3, P= .03), activities of daily living (ADL) (86.2 versus 80.8, P= .030), quality of life (70.1 versus 60.9, P= .008), 12M ADL (90.0 versus 85.1, P= .023), and 24M ADL (91.9 versus 87.2, P= .016). A higher proportion of patients achieved Minimal Clinically Important Difference for pain at 6 months for those having no releases versus released (92.3% versus 81.0%, P= .021). No significant associations were found between preoperative deformity and preoperative or postoperative KOOS.

The addition of soft tissue releases after bony cuts is associated with worse KOOS scores out to 2 years and was more prevalent in knees with worse deformity, while no such association was found for alignment.

The addition of soft tissue releases after bony cuts is associated with worse KOOS scores out to 2 years and was more prevalent in knees with worse deformity, while no such association was found for alignment.

Female gender and surgical drain use have been associated with an increased transfusion risk following single-anesthetic bilateral total knee arthroplasty (SBTKA). This study evaluated allogenic blood transfusion rates among female and male patients undergoing SBTKA with intraoperative tourniquet, tranexamic acid and contemporary blood transfusion thresholds but without surgical drain use.

We performed a retrospective electronic medical record review for 125 consecutive patients undergoing SBTKA (250 knees) between May 1, 2015 and July 10, 2021. Patient demographic characteristics (age, gender, body mass index, American Society of Anesthesiologists), preoperative and postoperative hemoglobin levels, perioperative transfusions, operative time, and hospital length of stay were compared between 76 female (60.8%) and 49 male (39.2%) patient cohorts using paired Student's t-test or Fisher's exact test with a P value <.05 for significance.

No patient in either gender-based cohort received a perioperative allogeneic or autologous blood transfusion (P= 1). There were no significant differences in patient demographic features or medical comorbidities. Male patients had significantly higher mean preoperative (14.7 versus 13.7 g/dL, P < .01) and postoperative (12.7 versus 11.8 g/dL, P < .01) hemoglobin levels and a shorter mean hospital length of stay (2.5 versus 3.0 days, P < .01). There was no difference in the mean operative time (154.7 versus 150.7minutes, P= .34) or change in the hemoglobin level (2.1 versus 1.9 g/dL, P= .27).

SBTKA can be performed with a limited risk of perioperative transfusion with a combination of intraoperative tourniquet, tranexamic acid, conservative blood transfusion criteria, and avoidance of postoperative drain use. Study results were not influenced by patient gender.

This is a level III, retrospective cohort study.

This is a level III, retrospective cohort study.