Total Hip and Total Knee Arthroplasty Outpatient Case Volume During the 2020 COVID-19 Pandemic in New York and California.

BACKGROUND: Inpatient total hip and total knee arthroplasty were substantially impacted by the SARS-CoV-2 (COVID-19) pandemic. We sought to characterize the transition of total joint arthroplasty (TJA) to the outpatient setting in 2 large state health systems during this pandemic. METHODS: Adult patients who underwent primary elective TJA between January 1, 2016 and December 31, 2020 were retrospectively reviewed using the New York Statewide Planning and Research Cooperative System and California Department of Health Care Access and Information datasets. Yearly inpatient and outpatient case volumes and patient demographics, including age, sex, race, and payer coverage, were recorded. Continuous and categorical variables were compared using descriptive statistics. Significance was set at P < .05. RESULTS: In New York during 2020, TJA volume decreased 16% because 22,742 fewer inpatient TJAs were performed. Much of this lost volume (46.6%) was offset by a 166% increase in outpatient TJA. In California during 2020, TJA volume decreased 20% because 34,114 fewer inpatient TJAs were performed. Much of this lost volume (37%) was offset by a 47% increase in outpatient TJA. CONCLUSIONS: This present study demonstrates a marked increase in the proportion of TJA being performed on an outpatient basis in both California and New York. In both states, despite a decrease in overall TJA volume in 2020, outpatient TJA volume increased markedly. LEVEL OF EVIDENCE: Therapeutic Level IV, Retrospective Cohort Study.

Increased Risk of Venous Thromboembolism in Patients with Postoperative Anemia After Total Joint Arthroplasty: Are Transfusions to Blame?

BACKGROUND: The relationship between anemia and the risk of venous thromboembolism (VTE) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) remains unclear. Red blood cell (RBC) transfusions, which have been shown to have thrombogenic effects, may explain conflicting data. This study sought to elucidate the relationship between anemia, RBC transfusions, and VTE following total joint arthroplasty (TJA). METHODS: Using the International Classification of Diseases, Tenth Revision (ICD-10) and Current Procedural Terminology (CPT) codes, the Premier Healthcare Database was queried for all adults who underwent primary elective THA or TKA from January 2015 to December 2020. Patients were classified into 3 cohorts: those who did not have a diagnosis of anemia and did not receive an RBC transfusion (the control group), those with acute blood loss anemia who did not receive a transfusion (the anemia without transfusion group), and those with acute blood loss anemia who did receive a transfusion (the anemia with transfusion group). The primary outcomes assessed were the 90-day rate and risk of deep vein thrombosis (DVT), pulmonary embolism (PE), and aggregate VTE. Analysis of variance and pairwise comparisons were used to compare groups. Multivariable analyses were performed to account for confounding factors. RESULTS: The 1,290,815 patients identified as having undergone TJA included 1,078,507 control patients (83.6%), 198,233 patients who had anemia without transfusion (15.4%), and 14,075 patients who had anemia and transfusion (1.1%). Age, sex, race, length of hospital stay, and hospital costs were significantly different between the 3 groups. After adjusting for confounding factors, there was no difference between the anemia without transfusion group and the control group with regard to DVT (adjusted odds ratio [OR], 0.97 [95% confidence interval (CI), 0.89 to 1.06]; p = 0.500), PE (adjusted OR, 1.04 [95% CI, 0.92 to 1.18]; p = 0.543), and VTE (adjusted OR, 0.99 [95% CI, 0.92 to 1.06]; p = 0.697). However, patients with anemia and transfusion had an increased risk of PE (adjusted OR, 1.83 [95% CI, 1.34 to 2.51]; p < 0.001) and VTE (adjusted OR, 1.39 [95% CI, 1.14 to 1.70]; p = 0.001) compared with patients in the control group. CONCLUSIONS: Patients with acute blood loss anemia who received a transfusion were at increased risk for developing VTE following TJA, whereas patients with anemia who did not receive a transfusion were not. Orthopaedic surgeons need to be aware of the risks of transfusion and individualize the use of transfusions in their patients. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Refining the Role of Routine Synovial Alpha-Defensin in Periprosthetic Joint Infection Following Total Knee Arthroplasty: An Analysis of Limitations.

BACKGROUND: The utility of the synovial alpha-defensin test in diagnosing periprosthetic joint infections (PJIs) remains controversial. This study aimed to examine the diagnostic utility of this test. METHODS: A retrospective review was conducted to identify adults evaluated for PJI following total knee arthroplasty at a single institution. Patient demographics, laboratory results, and operative details were recorded. Using the 2018 Musculoskeletal Infection Society (MSIS) criteria, cases were categorized as definitive, inconclusive, or negative for PJI. The sensitivity, specificity, positive predictive value, and negative predictive value of each MSIS criterion was determined. The number of patients whose PJI diagnosis was contingent on alpha-defensin positivity was calculated. RESULTS: Overall, 172 total knee arthroplasty patients were included, who had an average age of 70.4 years (range, 39 to 95). Of the 21 patients who met major criteria, 20 (95.2%) were alpha-defensin positive. Of the remaining 151 patients, 85 did not meet minor criteria, all of whom were alpha-defensin negative. Among the 30 patients who met minor criteria, 28 (93.3%) were alpha-defensin positive and 2 (6.7%) were negative. The remaining 36 patients were deemed inconclusive preoperatively. In total, alpha-defensin testing changed the diagnosis in only 9 of 172 patients (5.2%). The sensitivity, specificity, positive predictive value, and negative predictive value of alpha-defensin in this cohort were 94.1, 100, 100, and 97.6, respectively. CONCLUSION: Alpha-defensin may assist in the diagnosis of PJI when a preoperative workup is inconclusive. However, this test is often unnecessary when the diagnosis of PJI can be made using the 2018 MSIS criteria.

Clinical outcomes of cemented distal femur replacements with all-polyethylene tibial components for oncologic indications.

BACKGROUND: Endoprosthetic distal femoral replacement (DFR) is a well-established salvage procedure following resection of malignant tumors within the distal femur. Use of an all-polyethylene tibial (APT) component is cost-effective and avoids failure due to locking-mechanism issues and backside wear, but limits modularity and the option for late liner exchange. Due to a paucity of literature we sought to answer three questions: (1) What are the most common modes of implant failure for patients undergoing cemented DFR with APT for oncologic indications? (2) What is the survivorship, rate of all-cause reoperation, and rate of revision for aseptic loosening of these implants? And (3) Is there a difference in implant survivorship or patient demographics between cemented DFRs with APT performed as a primary reconstruction vs those performed as a revision procedure? AIM: To assess outcomes of cemented DFRs with APT components used for oncologic indications. METHODS: After Institutional Review Board approval, a retrospective review of consecutive patients who underwent DFR between December 2000 to September 2020 was performed using a single-institutional database. Inclusion criteria consisted of all patients who underwent DFR with a GMRS® (Global Modular Replacement System, Stryker, Kalamazoo, MI, United States) cemented distal femoral endoprosthesis and APT component for an oncologic indication. Patients undergoing DFR for non-oncologic indications and patients with metal-backed tibial components were excluded. Implant failure was recorded using Henderson's classification and survivorship was reported using a competing risks analysis. RESULTS: 55 DFRs (55 patients) with an average age of 50.9 ± 20.7 years and average body mass index of 29.7 ± 8.3 kg/m2 were followed for 38.8 ± 54.9 mo (range 0.2-208.4). Of these, 60.0% were female and 52.7% were white. The majority of DFRs with APT in this cohort were indicated for oncologic diagnoses of osteogenic sarcoma (n = 22, 40.0%), giant cell tumor (n = 9, 16.4%), and metastatic carcinoma (n = 8, 14.6%). DFR with APT implantation was performed as a primary procedure in 29 patients (52.7%) and a revision procedure in 26 patients (47.3%). Overall, twenty patients (36.4%) experienced a postoperative complication requiring reoperation. The primary modes of implant failure included Henderson Type 1 (soft tissue failure, n = 6, 10.9%), Type 2 (aseptic loosening, n = 5, 9.1%), and Type 4 (infection, n = 6, 10.9%). There were no significant differences in patient demographics or rates of postoperative complications between the primary procedure and revision procedure subgroups. In total, 12 patients (21.8%) required a revision while 20 patients (36.4%) required a reoperation, resulting in three-year cumulative incidences of 24.0% (95%CI 9.9%-41.4%) and 47.2% (95%CI 27.5%-64.5%), respectively. CONCLUSION: This study demonstrates modest short-term survivorship following cemented DFR with APT components for oncologic indications. Soft tissue failure and endoprosthetic infection were the most common postoperative complications in our cohort.

Tranexamic Acid and Prothrombotic Complications Following Total Hip and Total Knee Arthroplasty: A Population-Wide Safety Analysis Accounting for Surgeon Selection Bias.

BACKGROUND: Tranexamic acid (TXA) utilization during total joint arthroplasty (TJA) has become ubiquitous. However, concerns remain regarding the risk of thrombotic complications. The goal of this study was to examine the risk of prothrombotic complications in patients who received TXA during total knee (TKA) and total hip arthroplasty (THA). METHODS: The Premier Healthcare Database was queried for patients who underwent elective TJA. TXA utilization trends were described from 2008 to 2020. Two analyses were performed using ICD-10 codes from 2016 to 2020: (1) patients who received TXA compared to patients who did not receive TXA and, (2) to account for surgeon selection bias, patients whose surgeon utilized TXA consistently (≥90% of cases) compared to patients whose surgeons used TXA infrequently (≤30% of cases). Multivariate and instrumental variable analyses (IVA) were performed to assess outcomes while accounting for confounding factors. TXA utilization increased from 0.1% of cases in 2008 to 89.2% in 2020. From 2016 to 2020, 1,120,858 TJAs were identified (62.1% TKA, 27.9% THA), of which 874,627 (78.0%) received TXA. RESULTS: Patients who received TXA were at lower risk of prothrombotic (adjusted Odds Ratio (aOR) 0.82, P < .001), bleeding (aOR 0.75, P < .001), and infectious complications (aOR 0.91, P < 0.001). Furthermore, patients who underwent surgery from surgeons who utilized TXA consistently were at lower risk for prothrombotic (aOR 0.90, P < .001) and bleeding (aOR 0.72, P < .001) complications. CONCLUSION: The widespread utilization of TXA during elective TJA was not associated with increased rates of prothrombotic complications. These findings persisted after accounting for surgeon selection bias. LEVEL OF EVIDENCE: Level III.

The Association of Baseball Pitch Delivery and Kinematic Sequence on Stresses at the Shoulder and Elbow Joints.

Although there is a commonly held belief within the baseball community that delivery from the stretch confers more stress at the elbow and shoulder joints than delivery from the windup, there remains little evidence in the literature investigating this hypothesis. This study aimed to help address this gap in the literature by studying both intra-pitcher kinematic sequence variability, and intra-pitcher joint torque variability when throwing from the windup vs. the stretch. We hypothesized that 1) each pitchers' kinematic sequence would remain similar whether throwing from the windup or stretch, and 2) Kinematic sequence would influence peak arm torque more than delivery method. This cross-sectional 3D biomechanical study included 88 pitches thrown by ten (6 collegiate, 4 high school) pitchers with a mean age of 17.60 ± 2.63 years. Pitch velocity, throwing shoulder/elbow torques and the kinematic sequence of each pitch utilizing segmental peak angular velocities were captured. No statistically significant differences in ball velocity (p = 0.17), peak shoulder external rotation torque (p = 0.80), shoulder extension torque (p = 0.97), or elbow valgus torque (p = 0.83) were found between delivery approaches. Three primary kinematic sequences were identified. Shoulder external rotation torque [F(53,2) = 10.992, ɳ2 = .293, p < 0.00], shoulder extension torque [F(53,2) = 15.517, ɳ2 = .369, p < 0.00] and elbow valgus torque [F(53,2) = 9.994, ɳ2 = .274, p < 0.00] did vary significantly across these three kinematic sequence patterns. Our data suggest that the kinematic sequence influences shoulder and elbow torque more than the delivery approach. Instructing ideal kinematic sequence may be more influential for injury avoidance than delivery method.

Kinematic sequence patterns in the overhead baseball pitch.

Conceptually, an efficient baseball pitch demonstrates a proximal-to-distal transfer of segmental angular velocity. Such a timing pattern (or kinematic sequence) reduces stress on musculoskeletal structures of the throwing arm and maximises ball velocity. We evaluated the variability of kinematic sequences in 208 baseball pitches. 3D biomechanical pitch analyses were performed on 8-10 fastball pitches from 22 baseball pitchers (5 high school, 11 collegiate and 6 professional). The kinematic sequence patterns - time of peak angular velocity of five body segments: pelvis, trunk, arm, forearm and hand - were measured. None of the pitches analysed demonstrated an entirely proximal-to-distal kinematic sequence. Fourteen different kinematic sequence patterns were demonstrated, with the most prevalent sequence being pelvis â†’ trunk â†’ arm â†’ hand â†’ forearm. Fewer than 10% of the pitchers performed only one kinematic sequence pattern across the sampled pitches. The variability of the kinematic sequence was similar in high-school pitchers and professionals. Previous studies report that deviation from the proximal-to-distal kinematic sequence is associated with increased injury risk. As a method of evaluating the efficient transfer of energy to the hand, the kinematic sequence may provide insight to injury risk in the future. The ideal kinematic sequence and ideal variability of the sequence when throwing have yet to be determined.