Faculty Bibliography

PURPOSE/OBJECTIVE:Kinematically designed total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Traditional posterior-stabilized (PS) TKA designs, on the other hand, simplify knee kinematics and may improve TKA cost-effectiveness. The purpose of this study was to compare outcomes of patients who underwent primary TKA using either a traditional PS or kinematically designed TKA. METHODS:This retrospective study examined all patients who underwent primary TKA using either a kinematically or a traditional PS designed TKA implant, with a minimum follow-up of 2 years. Patient demographics, complications, readmissions, revision rates and causes, range of motion (ROM) and patient reported outcomes (KOOS, JR) were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from revision, and multivariate regression was performed to control for confounding variables. RESULTS:A total of 396 TKAs [173 (43.7%) with a kinematic design, 223 (56.3%) with a traditional design] with a mean follow-up of 3.48 ± 1.51 years underwent analysis. Revision rates did not differ between groups (9.8% vs. 6.7%, p = 0.418). In Kaplan-Meier analysis at 2-year follow-up, freedom from all-cause revision (96.4% vs. 93.1%, p = 0.139) were similar between groups. The two cohorts had no significant difference in aseptic loosening at 2 years (99.6% vs. 97.1, p = 0.050) and at latest follow up (92.7% vs. 96.4%, p = 0.279). KOOS, JR scores and post-operative ROM were similar between groups. CONCLUSION/CONCLUSIONS:This study demonstrated similar mid-term outcomes following the use of both a kinematically designed and a traditionally designed implant in primary TKA patients. LEVEL OF EVIDENCE/METHODS:Retrospective study-III.

Accurate and reproducible acetabular component positioning is among the most important technical factors affecting outcomes of total hip arthroplasty. Although several studies have investigated the influence of pelvic tilt and obliquity on functional acetabular anteversion, the effect of pelvic axial rotation has not yet been established. We analyzed a generic simulated pelvis created using preoperative full-body standing and sitting radiographs. A virtual acetabulum was placed in 144 different scenarios of acetabular anteversion and abduction angles. In each scenario, the effects of pelvic tilt and pelvic axial rotation on different combinations of acetabular orientations were assessed. The change in acetabular anteversion was 0.75° for each 1° of pelvic tilt and was most linear in abduction angles of 40°±45°. The change in acetabular anteversion was 0.8° for each 1° of pelvic axial rotation. Surgeons may consider adjusting acetabular anteversion in fixed axial pelvic deformities when the degree of deformity affects functional acetabular positioning, assessed from preoperative standing and sitting weight-bearing radiographs. [Orthopedics. 2023;46(1):e27-e30.].

BACKGROUND:Airborne biologic particles (ABPs) can be measured intraoperatively to evaluate operating room (OR) sterility. Our study examines the role of OR size on air quality and ABP count in primary total hip arthroplasty (THA). METHODS:at a single academic institution from April 2019 to June 2020. Temperature, humidity, and ABP count per minute were recorded with a particle counter intraoperatively and cross-referenced with surgical data from the electronic health records using procedure start and end times. Descriptive statistics were used to evaluate differences in variables. P-values were calculated using t-test and chi-squared test. RESULTS:A total of 116 primary THA cases were included: 18 (15.5%) in the "small" OR and 98 (84.5%) in the "large" OR. Between-group comparisons revealed significant differences in temperature (small OR: 20.3 ± 1.23 C versus large OR: 19.1 ± 0.85 C, P < .0001) and relative humidity (small OR: 41.1 ± 7.24 versus large OR: 46.9 ± 7.56, P < .001). Significant percent decreases in ABP rates for particles measuring 2.5 um (-125.0%, P = .0032), 5.0 um (-245.0%, P = .00078), and 10.0 um (-413.9%, P = .0021) were found in the large OR. Average time spent in the OR was significantly longer in the large OR (174 ± 33 minutes) compared to the small OR (151 ± 14 minutes) (P = .00083). CONCLUSION/CONCLUSIONS:Temperature and humidity differences and significantly lower ABP counts were found in the large compared to the small OR despite longer average time spent in the large OR, suggesting the filtration system encounters less particle burden in larger rooms. Further research is needed to determine the impact this may have on infection rates.

BACKGROUND:Aseptic loosening persists as one of the leading causes of failure following cemented primary total knee arthroplasty (TKA). Cement technique may impact implant fixation. We hypothesized that there is variability in TKA cement technique among arthroplasty surgeons. METHODS:A 28-question survey regarding variables in surgeons' preferred TKA cementation technique was distributed to 2,791 current American Association of Hip and Knee Surgeons (AAHKS) members with a response rate of 30.8% (903 respondents). Patterns of responses were analyzed by grouping respondents by their answers to certain questions including cementing technique, tibial cement location, and femoral cement location. RESULTS:A total of 73.5% reported performing at least 7 of 8 of the highest consensus techniques, including vacuum mixing (79.9%), using two bags (76.1%), tibial implant first (95.2%), single-stage cementing (96.9%), compression of the implants in extension (91.7%), and use of a tourniquet (84.3%). Medium and high viscosity cement was most commonly used (37.9 and 37.8%, respectively). Finger pressurization was most common (76.1%) compared to a gun (29.8%). There were 26.5% of respondents performing 6 or fewer of the most common majority techniques and seemed to perform other less common techniques (eg, use of a single bag of cement, trialing or closure prior to cement curing, and heating to accelerate cement curing). Cement was most commonly applied to the entire bone and implant surface on both the tibia (46.4%) and femur (47.7%), leaving much variation in the remaining cement application location responses. DISCUSSION/CONCLUSIONS:There appears to be variability in cemented TKA technique among arthroplasty surgeons. There were 26.5% of respondents performing less of the majority techniques and also performed other additional low-response rate techniques. Further studies that look at the impacts of variation in techniques on outcomes may be warranted. Our study demonstrates the need for defining best practices for cement technique given the substantial variability identified.

BACKGROUND:Different approaches for total hip arthroplasty (THA) may offer advantages in regard to achieving same-day-discharge (SDD) success. METHODS:We retrospectively identified patients aged ≥ 18 years who underwent elective primary THA from 2015 to 2020 who were formally enrolled in a single institution's SDD program. A total of 1,127 and 207 patients underwent THA via direct anterior approach and posterior approach, respectively, were included. Cohorts were assigned based on approach. The primary outcome was failure-to-launch, defined as hospital stay extending past 1 midnight. Secondary outcomes included Forgotten Joint Score-12, Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, 90-day readmission and revision rate, and surgical time. Patient-reported outcomes were collected at 3 and 12 months. RESULTS:After controlling for demographic differences, posterior approach patients had higher rates of failure-to-launch (12.1% versus 5.9%, P = .002) and longer surgical times (99 versus 80 minutes; P < .001) compared to direct anterior approach patients. The cohorts had similar readmission (1.7% versus 1.4%; P = .64) and revision rates (1% versus 1%; P = .88). The magnitude of improvement in Hip Disability and Osteoarthritis Outcome Score for Joint Replacement scores from preoperative to 12 months was similar between cohorts (35.3 versus 34.5; P = .42). The differences in outcome scores between cohorts at each time point were not considered clinically significant. CONCLUSION/CONCLUSIONS:Our analysis suggests that patient selection and surgical approach may be important for achieving SDD. Surgical approach did not significantly impact readmission or revision rates nor did it have a meaningful impact on patient-reported outcomes in the first year after surgery.

BACKGROUND:Prior literature has demonstrated that diabetic (DM) patients undergoing total joint arthroplasty (TJA) with elevated preoperative HbA1c scores have poorer clinical outcomes. However, no literature has reported the effect of undergoing TJA on laboratory markers of glycemic control. This study sought to evaluate effect of undergoing TJA on postoperative glycemic control and outcomes. METHODS:This retrospective study reviewed all patients with DM who underwent primary, elective TJA at our high volume orthopedic institution. Included patients had at least one HbA1c value 3 months to 2 weeks pre-surgery and 3-6 months after surgery. Changes in HbA1c from before to after surgery were calculated. Change in HbA1c greater than 1.0% was considered clinically meaningful. Change in HbA1c was analyzed and stratified into subgroups. RESULTS:In total, 770 primary TJA patients were included. Patients with preoperative HbA1c > 7% vs. ≤ 7% were significantly more likely to have clinically meaningful post-TJA decrease in HbA1c (24.5 vs. 2.9%, p < 0.001). Patients with preoperative HbA1c > 8 were significantly more likely to have decrease of > 2.0 compared to those with HbA1c < 8 (p < 0.001). Multivariate regression revealed that preop HbA1c > 7.0, former and current smokers, males, and African-Americans were significantly more likely to achieve clinically meaningful decrease in HbA1c. Additionally, postoperative increase in HbA1c > 1% was associated with significantly higher 90-day ED visits. DISCUSSION/CONCLUSIONS:Patients with higher preoperative HbA1c were more likely to have clinically meaningful decreases in HbA1c postoperatively. A combination of preoperative medical optimization and improvements in mobility after TJA may play a role in these changes. Those with elevated HbA1c can have meaningful improvement in HbA1c after TJA.

BACKGROUND:Modern fluted titanium-tapered stems (FTTS) have been increasingly utilized to achieve primary stability in conversion and revision total hip arthroplasty with major femoral bone loss. This study sought to determine the radiographic and clinical outcomes of a monoblock FTTS in patients who had major femoral bone loss. METHODS:A multicenter retrospective observational study of all total hip arthroplasty patients who received a monoblock FTTS who had up to 5-year radiographic follow-up was conducted. Only patients with femoral Paprosky classifications of IIIa, IIIb, and IV were included. Eighty-one monoblock FTTS were examined. Median clinical follow-up was 29 months (range, 18 to 58). Stem subsidence and loosening were assessed on most recent radiographs. All-cause revisions and stem survivals were assessed. RESULTS:Median subsidence was 1.4 millimeters (mm) (range, 0 to 15.0). Sixteen (23.9%) and 3 (4.5%) stems had subsidence greater than 5 and 10 mm, respectively. All stems not acutely revised appeared stable, without evidence of loosening, at latest follow-up. Ten hips (12.3%) required reoperations. Of these, only 5 (6.2%) stems were removed; 4 due to periprosthetic joint infection and 1 for surgical exposure during acetabular revision. Kaplan-Meier analyses yielded an all-cause stem survivorship of 95.1% at 2-years and 87.1% at 4-years. Stem survivorships excluding septic causes was 98.8% at both 2 and 4 years. CONCLUSION/CONCLUSIONS:Monoblock FTTS in complex femoral reconstruction cases showed encouraging clinical and radiographic results in patients who had severe femoral bone loss at median 29 months follow-up.

INTRODUCTION/BACKGROUND:The optimal administration of dexamethasone for postoperative pain management and recovery following primary, elective total joint arthroplasty (TJA) remains unclear. This study aimed to evaluate the effect of a second intravenous (IV) dose of dexamethasone on postoperative pain scores, inpatient opioid consumption, and functional recovery after total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS:A retrospective review was conducted of 2,256 primary elective THA, and 1,951 primary elective TKA between May 2020 and April 2021. Patients who received two perioperative doses (2D) of dexamethasone 10 mg IV were propensity-matched 1:1 to a control group who received one perioperative dose (1D). Primary outcomes were opiate consumption as morphine milligram equivalences (MMEs), postoperative pain as Verbal Rating Scale (VRS) pain scores, and functional status assessed by the Activity Measure for Post-Acute Care (AM-PAC) scores. RESULTS:The 2D THA and 2D TKA cohorts consumed significantly less opiates at the 24 to 48 hour and 48 to 72 hour intervals. The 2D TKA cohort had significantly lower total opiate consumption compared to the 1D TKA cohort. Compared to the 1D cohorts, the 2D THA cohort and 2D TKA cohorts had significantly lower pain scores at the 48 to 60 hour interval; additionally, the 2D TKA cohort had significantly lower pain scores in the 36 to 48 hour interval. AM-PAC scores did not differ between cohorts for both TKA and THA at any interval. CONCLUSION/CONCLUSIONS:The administration of a second perioperative dexamethasone dose significantly decreased opioid consumption in the immediate postoperative period. Inpatient opioid administration can be significantly reduced while maintaining comparable functional recovery and superior pain control.

BACKGROUND:Over the past decade, reimbursement models and target payments have been modified in an effort to decrease costs of revision total knee arthroplasty (rTKA) while maintaining the quality of care. The goal of this study was to investigate trends in revenue and costs associated with rTKA. METHODS:We retrospectively reviewed all patients who underwent rTKA between 2011 and 2021 at our institution. Patients were stratified into groups based on insurance coverage: Medicare, government-managed or Medicaid (GMM), or commercial insurance. Patient demographics were collected, as well as revenue, costs, and contribution margin (CM) of the inpatient episode. Changes over time as a percentage of 2011 numbers were analyzed. Linear regressions were used to determine trend significance. In the 10-year study period, 1,698 patients were identified with complete financial data. RESULTS:Overall total cost has increased significantly (P < .01). While revenues and CM for Medicare and Commercial patients remained steady between 2011 and 2021, CM for GMM patients decreased significantly (P = .01) to a low of 53.2% of the 2011 values. Since 2018, overall CM and revenues decreased significantly (P = .05, P = .01, respectively). CONCLUSION/CONCLUSIONS:While from 2011 to 2018 general revenues and CM were relatively steady, since 2018 they have decreased significantly to their lowest values in over a decade for GMM and commercial patients. This trend is concerning and may potentially lead to decreased access to care. Re-evaluation of reimbursement models for rTKA may be necessary to ensure the financial viability of this procedure and prevent issues with access to care. LEVEL OF EVIDENCE/METHODS:III.

INTRODUCTION/BACKGROUND:Round or oval implants are used in patellar resurfacing during total knee arthroplasty (TKA). However, whether component geometry affects clinical outcomes is unclear. This study aimed to determine if one implant shape conferred superior outcomes to the other. METHODS:A retrospective review of primary TKA cases performed from 2016 to 2020 was conducted at an urban, tertiary academic center. 400 consecutive, primary TKAs were included in these analyses. Cases were included if a surgeon used the round design then oval design for fifty consecutive cases. Baseline demographic data and radiographic measurements were assessed. Surgical data, reasons for revision, and patient reported outcome measures were analyzed. Independent samples t- and chi-squared tests were used to compare means and proportions. There were no demographic differences between the cohorts. RESULTS:Post-operative patellar tilt was statistically different between the cohorts. Sixteen patients required revision surgery; however, revision rates did not differ between cohorts. Of the nine round, one button was revised for infection. Of the seven oval, one button was revised for infection and one for loosening. Veterans RAND 12 Physical Component Score at three-months postoperatively was higher for the round cohort, but no differences were observed at one-year. CONCLUSION/CONCLUSIONS:While radiographic patellar tilt was significantly different between the cohorts, there was no clinical correlation in outcomes at three-months or one-year postoperatively. Longer-term follow-up studies are needed to evaluate the implications of patellar component design on outcomes and function. Nevertheless, the current study affirms that both designs are clinically equivalent which should be used to guide clinical decision-making.