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.

One of the primary aims of total knee arthroplasty (TKA) is restoration of the mechanical axis of the lower limb. Maintenance of the mechanical axis within 3° of neutral has been shown to result in improved clinical results and implant longevity. Handheld image-free robotic-assisted total knee arthroplasty (HI-TKA) is a novel way of performing TKA in the era of modern robotic-assisted TKA. The aim of this study is to assess the accuracy of achieving targeted alignment, component placement, clinical outcomes, as well as patient satisfaction after HI-TKA.

BACKGROUND:Indications for surgery may impact resource utilization in aseptic revision total knee arthroplasty (rTKA), and understanding these relationships would facilitate risk-stratification preoperatively. The purpose of this study was to investigate the impact of rTKA indications on readmission, reoperation, length of stay (LOS), and cost. METHODS:We reviewed all 962 patients who underwent aseptic rTKA at an academic orthopedic specialty hospital between June 2011-April 2020 with at least 90 days of follow-up. Patients were categorized based on their indication for aseptic rTKA as listed in the operative report. Demographics, surgical factors, LOS, readmission, reoperation and cost were compared between cohorts. RESULTS:There were significant differences in operative time among cohorts (p < 0.001), highest among the periprosthetic fracture group (164.2 ± 59.8 min). Reoperation rate was greatest in the extensor mechanism disruption cohort (50.0 %, p = 0.009). Total cost differed significantly among groups (p < 0.001), which was highest among the implant failure cohort (134.6 % of mean) and lowest for component malpositioning cohort (90.2 % of mean). Similarly, there were significant differences in direct cost (p < 0.001) which was highest in the periprosthetic fracture cohort (138.5 % of mean), and lowest in the implant failure cohort (90.5 % of mean). There were no differences in discharge disposition, or number of re-revisions among all groups. CONCLUSIONS:Operative time, components revised, LOS, readmissions, reoperation rate, total cost and direct cost following aseptic rTKA varied significantly between different revision indications. These differences should be noted for preoperative planning, resource allocation, scheduling, and risk-stratification. LEVEL OF EVIDENCE/METHODS:III, retrospective observational analysis.

BACKGROUND:Many studies have demonstrated that in patients whose primary language is not English, outcomes after orthopaedic surgery are worse compared to primary English speakers. The goal of this study was to compare perioperative outcomes in patients undergoing total knee arthroplasty (TKA) who prefer English as their first language versus those who prefer a different language. METHODS:We retrospectively reviewed all patients who underwent primary TKA from May 2012 to July 2021. Patients were separated into two groups based on whether English was their preferred primary language (PPL). Of the 13,447 patients who underwent primary TKA, 11,290 reported English as their PPL and 2,157 preferred a language other than English. Patients whose PPL was not English were further stratified based on whether they requested interpreter services. Multiple regression analyses were performed to determine the significance of perioperative outcomes while controlling for demographic differences. RESULTS:Our analysis found that non-English PPL patients had significantly lower rates of readmission (p=0.040), overall revision (p=0.028), and manipulation under anesthesia (MUA; p=0.025) within 90 days postoperatively. Sub analyses of the non-English PPL group showed that those who requested interpreter services had significantly lower one year revision (p<0.001) and overall MUA (p=0.049) rates. CONCLUSION/CONCLUSIONS:Our results demonstrate that TKA patients who communicated in English without an interpreter were significantly more likely to undergo revision, readmission, and MUA. These findings may suggest that language barriers may make it more difficult to identify postoperative problems or concerns in non-English speakers, which may limit appropriate postoperative care.

BACKGROUND:Patients undergoing total knee arthroplasty (TKA) are at increased risk of venous thromboembolism (VTE). Aspirin has been shown to be effective at reducing rates of VTE. In select patients, more potent thromboprophylaxis is indicated, which has been associated with increased rates of bleeding and wound complications. This study aimed to evaluate the effect of thromboprophylaxis choice on rates of early prosthetic joint infection (PJI) following TKA. METHODS:A review of 11,547 primary TKA patients from 2013 to 2019 at a single academic orthopaedic hospital was conducted. The primary outcome measure was PJI within 90 days of surgery as measured by Musculoskeletal Infection Society criteria. There were 59 (0.5%) patients diagnosed with early PJI. Chi-square and Welch-Two Sample t-tests were used to determine statistically significant relationships between thromboprophylaxis and demographic variables. Significance was set at p<0.05. Multivariate logistic regression adjusted for age, body mass index, sex, and Charlson comorbidity index was performed to identify and control for independent risk factors for early PJI. RESULTS:There was a statistically significant difference in the rates of early PJI between the aspirin and non-aspirin group (0.3 vs 0.8%, p<0.001). Multivariate logistic regressions revealed that patients given aspirin thromboprophylaxis had significantly lower odds of PJI (odds ratios (OR)=0.51, 95% Confidence Interval (CI) 0.29 to 0.89, p=0.019) compared to non-aspirin patients. CONCLUSIONS:The use of aspirin thromboprophylaxis following primary TKA is independently associated with a lower rate of early PJIs. Arthroplasty surgeons should consider aspirin as the gold standard thromboprophylaxis in all patients in which it is deemed medically appropriate and should carefully weigh the morbidity of PJI in patients when non-aspirin thromboprophylaxis is considered.

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: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.

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.

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.

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.].