Faculty Bibliography

BACKGROUND:The effect of total knee arthroplasty (TKA) on the ankle joint is not entirely clear. The purpose of this study was to assess postoperative changes in the coronal alignment of the ankle joint in patients undergoing TKA for various degrees of knee deformity. METHODS:This retrospective study included 107 patients who had undergone TKA for primary osteoarthritis. In all cases, preoperative coronal alignment deformity of the knee was corrected in an attempt to restore the native mechanical axis of the knee. Patients were stratified into three groups according to the degree of knee coronal alignment correction achieved intraoperatively: Group 1 (< 10° varus/valgus correction, n=60), Group 2 (≥10° varus correction, n=30), and Group 3 (≥10° valgus correction, n=17). Knee/ankle alignment angles were measured on full-length, standing anteroposterior imaging preoperatively and postoperatively and included: hip-knee-ankle (HKA) angle, tibial plafond inclination (TPI), talar inclination (TI), and tibiotalar tilt (TTT) angle. RESULTS:Significant changes in ankle alignment, specifically with regard to TPI (9.5°±6.9, p<0.01) and TI (8.8° ±8.8, p=0.03) were noted in the ≥10° valgus correction group compared to the other two groups. Regardless of the degree of knee deformity correction, TKA did not lead to significant changes in the TTT angle. CONCLUSION/CONCLUSIONS:A correction of ≥10 degrees in a genu valgum deformity can affect ankle joint alignment, leading to alterations in the tibial plafond (TPI) and the talar inclination (TI). These findings need to be taken into consideration in assessing candidates for TKA as a possible cause of post-operative ankle pain.

BACKGROUND:Image-guided joint aspirations used to assist the diagnosis of periprosthetic joint infection (PJI) may commonly result in a dry tap-or insufficient fluid for culture and cell count analysis. Dry tap aspirations are painful and invasive for patients and often utilize a subsequent saline lavage to obtain a microbiology sample. Currently, there is a paucity of the literature addressing predictors that could suggest whether a dry tap will occur. The purpose of this study was to examine the effects of various factors on "dry tap" occurrence in patients with suspected PJI following total hip arthroplasty (THA). METHODS:A retrospective review was performed among THA patients suspected for PJI who received image-guided joint aspiration procedures at our institution from May 2016 to February 2020. The procedural factors included the imaging modality used for aspiration, anatomic approach, needle gauge size used, and the presence of a trainee. The patient-specific factors included number of prior ipsilateral hip surgeries, femoral head size, ESR/CRP values, and BMI. RESULTS:In total, 336 patients met our inclusion criteria. One hundred and twenty hip aspirations resulted in a dry tap (35.7%) where the patients underwent a saline lavage. Among the procedural and patient-specific factors, none of the factors were found to be statistically different between the two cohorts nor conferred any greater odds of a dry tap occurring. CONCLUSION/CONCLUSIONS:No associations with dry tap occurrence were found among the procedural and patient-specific factors studied. Further research is needed to identify additional factors that may be more predictive of dry taps.

INTRODUCTION/BACKGROUND:Although tourniquet use in primary total knee arthroplasty (TKA) has been widely studied, the outcomes associated with tourniquet use in revision TKA (rTKA) remains relatively unexplored. This study investigates surgical outcomes and patient satisfaction in association with tourniquet use during aseptic rTKA. METHODS:We retrospectively reviewed all patients who underwent rTKA for aseptic causes at our institution from 2011-2020. Patients were separated into two cohorts based on tourniquet inflation during the procedure. Outcomes of interest included estimated blood loss (EBL), change in hemoglobin (Hb), surgical time, length-of-stay (LOS), reoperation rate, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS,JR) scores. RESULTS:Of the 1,212 patients included, 1,007 (83%) underwent aseptic rTKA with the use of a tourniquet and 205 (17%) without the use of a tourniquet. The mean tourniquet inflation time was 93.0 minutes (SD:33.3 minutes). Blood loss was significantly less for patients in the tourniquet cohort as measured through EBL(224.1vs.325.1 mL,p<0.001) and change in preoperative to postoperative Hb(1.75vs.2.04 g/dL,p<0.001). There were no statistical differences in surgical time(p=0.267) and LOS(p=0.206) between the two groups. The reoperation rate was significantly greater for patients who did not have a tourniquet utilized (20.5%vs.15.0%,p=0.038). Delta improvement in KOOS,JR scores from baseline to 3-months postoperatively did not statistically differ between the two cohorts (p=0.560). CONCLUSION/CONCLUSIONS:While delta improvements in KOOS,JR scores were similar for both cohorts, patients who did not have a tourniquet inflated during aseptic rTKA had increased blood loss and were more likely to undergo subsequent reoperation compared to patients who did.

INTRODUCTION/BACKGROUND:Preoperative anemia (POA) is a significant predictor for adverse outcomes in primary total hip arthroplasty (THA). Current literature has studied POA stratified by severity. This study aims to find a threshold preoperative hemoglobin (Hb) value for increased risk of adverse outcomes in THA. METHODS:This was a retrospective analysis of primary THA patients with preoperative Hb values from 2014-2021 from an academic orthopedic specialty hospital. Demographics, surgical data, and post-operative outcomes were collected. Patients without preoperative Hb values within the electronic health record (EHR) system or values acquired >30 days preoperatively were excluded. Patients were grouped based on POA severity using WHO criteria. Secondary analysis using discrete preoperative Hb values was performed. P-values were calculated using ANOVA/Kruskal-Wallis and chi-square/Fisher's exact testing with p<0.05 considered significant. RESULTS:A total of 1,347 patients were included, 771(57.2%) patients with POA and 576(42.8%) with normal pre-operative Hb. In the POA group, 292(37.9%) were mild, 445(57.7%) moderate, and 34(4.4%) severe. Increased length of stay (LOS) was seen in moderate (3.9+4.3vs.2.4+2.1,p<0.001) and severe (5.0+3.4vs.2.4+2.1,p<0.0001) groups compared to control. The severe group had higher 90-day readmission and revision rates compared to control. Analysis by discrete Hb values showed increased LOS in Hb values <11g/dL and a greater proportion of patients with Hb values <12g/dL were discharged to skilled nursing facilities. CONCLUSION/CONCLUSIONS:Patients with preoperative Hb <12g/dL should be assessed for other risk factors that may predispose them to post-operative complications. Further investigation is warranted to develop more robust perioperative management strategies for POA patients undergoing THA.

PURPOSE/OBJECTIVE:The purpose of the study was to utilize a large-scale biomorphometric computer tomography (CT) database to determine the desirable starting point and angle for placement of the femoral intramedullary rod in the sagittal plane. METHODS:A CT-based modeling and analytics system (SOMA, Stryker, Mahwah, NJ) was used to evaluate 1029 entire-femur CT scans. From this, 19,464 simulations were run to test whether a 20 cm intramedullary rod, with a radius of 4 mm, would successfully pass through the femoral canal before contacting cortical bone. First, modelling included varying angles from 0-6 degrees in the sagittal plane, at 1-degree intervals. Next, the start point was adjusted with an assumed 3 degrees of induced flexion in comparison to the mechanical axis. RESULTS:A total of 5012 simulations were able to place the femoral intramedullary rod 20 cm into the canal. The angle of the rod that created the highest proportion of successful jig placement was at a 3-degree angle of induced flexion to the orthogonal plane of the transepicondylar axis (TEA), with 33.7% successful jig placements. The starting point for the greatest proportion of successful guide placements was 48.5% along the distance between the sTEA, slightly closer to the lateral side. In the AP plane, the average distance to the ideal start point was 12.1 mm anterior to the PCL. CONCLUSION/CONCLUSIONS:By examining over a thousand femoral CT scans, an angle of 3 degrees of induced flexion was identified in the sagittal plane with the highest proportion of successful placement of an intramedullary rod before cortical contact. It is important to note the high rate of failure in completely inserting the 20 mm rod. LEVEL OF EVIDENCE/METHODS:This is a prospective computer based model.

BACKGROUND:Obesity is a recognized risk factor for severe knee osteoarthritis. However, it remains unclear how obesity prevalence trends in the current population undergoing total knee arthroplasty (TKA) compare with those seen in individuals not undergoing this procedure. In this study, we assessed the yearly trends in body mass index (BMI) and obesity rates between patients who have undergone primary TKA and those in the general population. METHODS:We retrospectively reviewed all patients ≥18 years of age from January 2013 through December 2020 who underwent primary, elective TKA and those who had an annual routine physical examination at our institution within the same period. Baseline demographic characteristics were collected. The independent samples t test was used to compare means and the chi-square test was used to compare proportions between the 2 cohorts, and a linear regression was used to determine the significance of the yearly trends. RESULTS:A total of 11,333 patients who underwent primary TKA and 1,158,168 patients who underwent an annual physical examination were included in this study. After adjusting for age, we found the mean BMI for the TKA group to be significantly greater (p < 0.001) every year compared with the annual physicals group. The proportion of patients who were categorized into any obesity class (BMI, ≥30 kg/m2), Class-I obesity (BMI, 30 to 34.9 kg/m2), Class-II obesity (BMI, 35 to 39.9 kg/m2), and Class-III obesity (BMI, ≥40 kg/m2) was significantly higher for the TKA group each year compared with the annual physicals group. An analysis of trends over time showed a significantly increasing trend (p < 0.001) in BMI and obesity rates for the annual physicals group, but a stable trend for patients undergoing TKA. CONCLUSIONS:Patients who underwent TKA continued to have higher BMI than the general population, which showed a steady increase over time. Physicians need to continue in their efforts to educate patients on weight management and healthy lifestyles to potentially delay the need for a surgical procedure. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

INTRODUCTION/BACKGROUND:Despite increased efforts towards patient optimization, some patients have undocumented conditions that can affect costs and quality metrics for institutions and physicians. This study evaluates the effect of documented and undocumented psychiatric conditions on LOS and discharge disposition following total hip arthroplasty (THA). METHODS:A retrospective review of all primary THAs from 2015-2020 at a high-volume academic orthopedic specialty hospital was conducted. Patients were separated into three cohorts: patients with a documented psychiatric diagnosis (+Dx), patients without a documented psychiatric diagnosis but with an actively prescribed psychiatric medication (-Dx), and patients without a psychiatric diagnosis or medication (control). Patient demographics, LOS, and discharge disposition were assessed. RESULTS:A total of 5,309 patients were included; 3,048 patients had no recorded psychiatric medications (control); 2,261 patients took at least one psychiatric medication, of which 1,513 (65.9%) and 748 (34.1%) patients were put in the -Dx and +Dx cohorts, respectively. ASA Class differed between groups (<0.001). The -Dx and +Dx groups had increased LOS (3.15±2.37 (75.6±56.9) and 3.12±2.27 (74.9±54.5) versus 2.42±1.70 (57.6±40.8) days (hours), p<0.001) and were more likely to be discharged to a secondary facility (23.0% and 21.7% versus 13.8%, p<0.001) than the control group. Outcomes did not significantly differ between the -Dx and +Dx cohorts. CONCLUSION/CONCLUSIONS:Most THA patients' psychiatric diagnoses were not documented. The presence of psychiatric medications was associated with longer LOS and a greater likelihood of discharge to secondary facilities. This has implications for both cost and quality metrics. Review of medications can help identify and optimize these patients before surgery.

INTRODUCTION/BACKGROUND:The purpose of this study is to report on the association between the number of stairs to enter home and length of stay (LOS), discharge disposition, and patient reported outcome measures (PROMs) among patients who underwent primary total joint arthroplasty (TJA). MATERIALS AND METHODS/METHODS:We retrospectively reviewed patients who underwent primary total hip or knee arthroplasty between January 2016 and March 2020. Only patients with documentation of the number of stairs to enter their homes were included in the study. The two cohorts were separated into four groups: none, 1-10, 11-20, and > 20 stairs. Collected variables included demographic data, LOS, discharge disposition, and PROMs. Chi-square and ANOVA were utilized to determine significance. RESULTS:Of the 1116 patients included, 510 underwent THA, and 606 underwent TKA. There was no statistical difference in LOS (THA: p = 0.308; TKA: p = 0.701) and discharge disposition (THA: p = 0.371; TKA: p = 0.484) in both cohorts regardless the number of stairs. There was no statistical difference in FJS-12 scores at 3 months (THA: p = 0.590; TKA: p = 0.206), 12 months (THA: p = 0.217; TKA: p = 0.845), and 21 months (THA: p = 0.782; TKA: p = 0.296) postoperatively for both cohorts. There was no statistical difference in HOOS, JR scores preoperatively (p = 0.278) and at 3 months postoperatively (p = 0.527) for the THA cohort, as well as KOOS, JR scores preoperatively and at 3 and 12 months postoperatively (p = 0.557; p = 0.522; p = 0.747) for the TKA cohort. CONCLUSION/CONCLUSIONS:We found no statistical differences in LOS, discharge disposition, and PROMs in patients who underwent TJA, irrespective of the number of stairs negotiated to enter their home. These findings can aid surgeons to provide preoperative education and reassurance to patients who have concerns with their discharge planning due to the walk-up stairway at their residence.

BACKGROUND:The purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA). METHODS:This is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores. RESULTS:Of 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval -0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores. CONCLUSION/CONCLUSIONS:Patients with a higher number of reported allergies may be at increased risk of PJI following TJA. LEVEL OF EVIDENCE/METHODS:Prognostic Level II.