Faculty Bibliography

BACKGROUND/UNASSIGNED:Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Conventional cruciate-retaining (CR) design in TKA has shown previous clinical success with lower complication rates. This study compared the patient-reported outcomes between the BCS and CR TKA designs. METHODS/UNASSIGNED:-tests. RESULTS/UNASSIGNED:= 0.028) than the CR cohort (n = 203). Both cohorts displayed a significant difference in delta improvements within their respective cohort when measuring FJS from 3 months to 1 year, 2 years, and 3 years after surgery. CONCLUSIONS/UNASSIGNED:The CR cohort performed better on average, compared to the BCS cohort in measures of KOOS, JR scores at the 2-year follow-up. The BCS cohort performed marginally better regarding FJS only at 1-year follow-up.

Osteoarthritis (OA) is the most common joint disease. Currently there are no effective methods that simultaneously prevent joint degeneration and reduce pain¹. Although limited evidence suggests the existence of voltage-gated sodium channels (VGSCs) in chondrocytes², their expression and function in chondrocytes and in OA remain essentially unknown. Here we identify Na_v1.7 as an OA-associated VGSC and demonstrate that human OA chondrocytes express functional Na_v1.7 channels, with a density of 0.1 to 0.15 channels per µm² and 350 to 525 channels per cell. Serial genetic ablation of Na_v1.7 in multiple mouse models demonstrates that Na_v1.7 expressed in dorsal root ganglia neurons is involved in pain, whereas Na_v1.7 in chondrocytes regulates OA progression. Pharmacological blockade of Na_v1.7 with selective or clinically used pan-Na_v channel blockers significantly ameliorates the progression of structural joint damage, and reduces OA pain behaviour. Mechanistically, Na_v1.7 blockers regulate intracellular Ca²⁺ signalling and the chondrocyte secretome, which in turn affects chondrocyte biology and OA progression. Identification of Na_v1.7 as a novel chondrocyte-expressed, OA-associated channel uncovers a dual target for the development of disease-modifying and non-opioid pain relief treatment for OA.

INTRODUCTION/UNASSIGNED:Dual-mobility (DM) implants for total hip arthroplasty (THA) have gained popularity due to their potential to reduce hip instability and dislocation events that may lead to revision surgery. These implants consist of a femoral head articulated within a polyethylene liner, which articulates within an outer acetabular shell, creating a dual-bearing surface. Our study aimed to report our observations on the survivorship of a novel DM implant for primary total hip arthroplasty at two years. METHODS/UNASSIGNED:We conducted a retrospective, multicenter study to assess the clinical outcomes of patients undergoing a THA with a novel DM implant (OR3O acetabular system™, Smith & Nephew, Inc., Memphis, TN) from January 2020 to September 2021. Patient demographics, surgical information, and survivorship data were collected from medical records for patients with a minimum of two years of follow-up. Primary outcomes included overall implant survivorship at two years as well as aseptic survivorship, revision rates of the DM acetabular shell, and average time to revision. Patient-reported outcomes were collected in the form of HOOS JR. RESULTS/UNASSIGNED:A total of 250 hips in 245 patients had a minimum two-year follow-up. Primary osteoarthritis (80%) was the most common indication for index THA. The average aseptic survivorship of the DM acetabular components at two years for the cohort was 98.4% and survivorship of the acetabular implants overall was 97.6%. There were a total of four (1.6%) aseptic revisions of the DM acetabular component. Reasons for aseptic acetabular revision included one case of instability, one intraprosthetic dislocation, one periprosthetic acetabular fracture, and one malpositioned acetabular cup resulting in impingement. The mean time of follow-up was 893.9 days. Eighty-seven patients had preoperative and two-year HOOS JR available. HOOS JR improved by an average of 38.5 points. CONCLUSION/UNASSIGNED:This novel DM acetabular implant demonstrates excellent survivorship at two years follow-up with low rates of instability and intraprosthetic dislocation and no episodes of metal-on-metal corrosion. Use of the DM implant demonstrated clinically relevant improvements in patient-reported outcomes at two years.

BACKGROUND:Younger age is associated with increased revision incidence following primary total hip arthroplasty, though the association between age and repeat revision following revision total hip arthroplasty (rTHA) has not been described. This study aimed to describe the incidences and indications for subsequent revision (re-revision) following rTHA based on age. METHODS:Patients undergoing aseptic rTHA from 2011 to 2021 with minimum 1-year follow-up were retrospectively reviewed. Patients were stratified into 3 groups based on age at the time of index rTHA (ie, <55 years, 55 to 74 years, and >74 years). Perioperative characteristics, complications, and re-revisions were compared between groups. RESULTS:Of 694 included rTHAs, those in the >74 age group were more likely to undergo rTHA for periprosthetic fracture (P < .001) while those in the <55 age group were more likely to undergo rTHA for metallosis/taper corrosion (P = .028). Readmissions (P = .759) and emergency department visits (P = .498) within 90 days were comparable across ages. Rates of re-revision were comparable at 90 days (P = .495), 1 year (P = .443), and 2 years (P = .204). Kaplan-Meier analysis of all-cause re-revision at latest follow-up showed a nonstatistically significant trend toward increasing re-revisions in the <55 and 55 to 74 age groups. Using logistic regressions, smoking and index rTHA for instability were independently associated with re-revision, while age at index surgery was not. CONCLUSIONS:While indications for rTHA differ across age groups, rates of 2-year re-revision are statistically comparable between groups. Further studies are warranted to understand the association between age, activity, and re-revision rates after 5 years postoperatively.

BACKGROUND:The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Procedure Coding System (ICD-10-PCS) was adopted in the U.S. in 2015. Proponents of the ICD-10-PCS have stated that its granularity allows for a more accurate representation of the types of procedures performed by including laterality, joint designation, and more detailed procedural data. However, other researchers have expressed concern that the increased number of codes adds further complexity that leads to inaccurate and inconsistent coding, rendering registry and research data based on ICD-10-PCS codes invalid and inaccurate. We aimed to determine the accuracy of the ICD-10-PCS for identifying cemented fixation in primary total hip arthroplasty (THA). METHODS:We retrospectively reviewed all cemented primary THAs performed at 4 geographically diverse, academic medical centers between October 2015 and October 2020. Cemented fixation was identified from the ICD-10-PCS coding for each procedure. The accuracy of an ICD-10-PCS code relative to the surgical record was determined by postoperative radiograph and chart review, and cross-referencing with institution-level coding published by the American Joint Replacement Registry (AJRR) was also performed. RESULTS:A total of 552 cemented THA cases were identified within the study period, of which 452 (81.9%) were correctly coded as cemented with the ICD-10-PCS. The proportion of cases that were correctly coded was 187 of 260 (72%) at Institution A, 158 of 185 (85%) at Institution B, 35 of 35 (100%) at Institution C, and 72 of 72 (100%) at Institution D. Of the 480 identified cemented THA cases at 3 of the 4 institutions, 403 (84%) were correctly reported as cemented to the AJRR (Institution A, 185 of 260 cases [71%]; Institution B, 185 of 185 [100%]; and Institution C, 33 of 35 [94%]). Lastly, of these 480 identified cemented THA cases, 317 (66%) were both correctly coded with the ICD-10-PCS and correctly reported as cemented to the AJRR. CONCLUSIONS:Our findings revealed existing discrepancies within multiple institutional data sets, which may lead to inaccurate reporting by the AJRR and other registries that rely on ICD-10-PCS coding. Caution should be exercised when utilizing ICD-10 procedural data to evaluate specific details from administrative claims databases as these inaccuracies present inherent challenges to data validity and interpretation.

Intraoperative trochanteric fractures during primary and revision total hip arthroplasty typically occur during femoral canal preparation and component placement. Several fixation strategies, including wires, cables, cable grips, and plating, are available for fracture fixation. Surgeons should consider patient activity level preoperatively, bone mineral density, and fracture morphology when deciding on fixation strategies. Patient activity must be modified postoperatively to prevent fracture displacement and additional complications. Patients must be counseled postoperatively about the possibility of decreased clinical outcomes.

INTRODUCTION/BACKGROUND:The role of different femoral head materials for total hip arthroplasty (THA) has been widely studied in the context of wear properties and corrosion. Cobalt chrome (CoCr) femoral heads are commonly used as a standard of comparison to other materials such as ceramic and oxidized zirconium (OxZi). This study aims to evaluate the impact of femoral head material on clinical outcomes in elective primary THA patients. METHODS:Retrospective analysis of THA patients within the Medicare claims database between October 2017 and September 2020 using diagnosis-related group codes was conducted. Information collected included sex, age, Charlson Comorbidity Index, and femoral head type. Patients with CoCr femoral heads were compared against patients with either OxZi or ceramic femoral heads using 1:1 propensity score matching. Z-testing and Chi-square analysis were used to determine between-group significance. RESULTS:In total, 112,960 elective THA patients were included, with 56,480 in OxZi or ceramic and 56,480 in CoCr. Readmission rates were lower in patients that received OxZi or ceramic femoral heads at 30-day (p < 0.0001), 60-day (p < 0.0001), and 90-day postoperatively (p < 0.0001) compared to CoCr. Mortality rates were also lower in patients that received OxZi or ceramic femoral heads at 30-day (p = 0.004), 60-day (p = 0.018), and 90-day postoperatively (p = 0.009) compared to CoCr. CONCLUSION/CONCLUSIONS:CoCr femoral heads had higher rates of readmissions and mortality compared to OxZi or ceramic. Further analysis of bearing surface combinations and sub-group analyses to determine significance between-group differences is needed. LEVEL III EVIDENCE/METHODS:Retrospective analysis.

INTRODUCTION/BACKGROUND:Multiple surgical approaches are used for primary total hip arthroplasty (pTHA) and revision total hip arthroplasty (rTHA). This study sought to investigate prevalence of discordance of pTHA and rTHA surgical approaches and to evaluate the impact of approach concordance on postoperative outcomes. METHODS:A multi-center retrospective review of patients who underwent rTHA from 2000 to 2021 was conducted at three large, urban academic centers. Patients who had a minimum one-year follow-up post-rTHA were included and grouped based on whether they received pTHA via a posterior (PA), direct anterior (DA), or laterally-based (DL) approach, and by concordance of index rTHA approach with their pTHA approach. Of the 917 patients studied, 839 (91.5%) were included in the concordant cohort and 78 (8.5%) in the discordant cohort. Patient demographics, operative characteristics, and postoperative outcomes were compared. RESULTS:Discordance was most prevalent in the DA-pTHA subset (29.5%), compared to the DL-pTHA subset (14.7%) or PA-pTHA subset (3.7%). Discordance varied significantly between primary approaches among all revisions, with DA-pTHA patients having the highest discordance rate for patients revised for aseptic loosening (46.3%, P<0.001), fracture (22.2%, P<0.001), and dislocation (33.3%, P<0.001). There were no differences between groups in dislocation rate, re-revision for infection, or re-revision for fracture. CONCLUSION/CONCLUSIONS:The results of this multicenter study showed patients who received pTHA via the DA were more likely to receive rTHA via a discordant approach compared to other primary approaches. Since approach concordance did not impact dislocation, infection, or fracture rates after rTHA, surgeons can feel reassured using a separate approach for rTHA.