Faculty Bibliography

INTRODUCTION/BACKGROUND:Although technology-assisted total hip arthroplasty (TA-THA) may improve implant positioning, it remains unknown whether TA-THA confers improved clinical outcomes. We sought to examine national TA-THA utilization trends and compare clinical outcomes between TA-THA and unassisted THA (U-THA). METHODS:Patients who underwent primary, elective THA from 2010 to 2018 were identified using the American College of Surgeons National Surgical Quality Improvement Program database. Demographic, perioperative, and 30-day outcomes were queried and collected. Patients were stratified based on whether they underwent TA-THA, which included computer navigation or robotics, and U-THA. Propensity score matching paired patients undergoing TA-THA or U-THA on a 1:1 basis. RESULTS:Of the 238,755 THA patients, 3,149 cases (1.3%) were done using TA-THA. Comparing the unmatched TA-THA and U-THA groups, race distribution (P < 0.001) and baseline functional status (P < 0.001) differed. Propensity score matching yielded 2,335 TA-THA and U-THA pairs. Perioperatively, the TA-THA cohort had longer mean surgical times (101.0 ± 34.0 versus 91.9 ± 38.8 minutes, P < 0.001), but lower transfusion rates (5.7% versus 7.8%, P = 0.005). As compared with the U-THA group, the TA-THA group had a shorter mean hospital length of stay (2.0 ± 1.1 versus 2.5 ± 2.0 days, P < 0.001) and a higher proportion of patients discharged home (85.8% versus 75.7%, P < 0.001). Notably, the TA-THA cohort had higher readmission rates (3.8% versus 2.4%, P < 0.001). Major complication and revision surgery rates did not markedly differ between groups. DISCUSSION/CONCLUSIONS:TA-THA utilization rates remain low among orthopaedic surgeons. As compared with U-THA, TA-THA yield mixed perioperative and 30-day outcomes. Surgeons must consider the clinical benefits and drawbacks of TA-THA when determining the proper surgical technique and technology for each patient. Clinical trials assessing long-term functional and clinical outcomes between U-THA and TA-THA are required to further elucidate the utility of assistive technologies in THA. LEVEL III EVIDENCE/UNASSIGNED:Retrospective Cohort Study.

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.

INTRODUCTION/BACKGROUND:Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is challenging to diagnose. We aimed to evaluate the impact of dry taps requiring saline lavage during preoperative intraarticular hip aspiration on the accuracy of diagnosing PJI before revision surgery. METHODS:A retrospective review was conducted for THA patients with suspected PJI who received an image-guided hip aspiration from May 2016 to February 2020. Musculoskeletal Infection Society (MSIS) diagnostic criteria for PJI were compared between patients who had dry tap (DT) versus successful tap (ST). Sensitivity and specificity of synovial markers were compared between the DT and ST groups. Concordance between preoperative and intraoperative cultures was determined for the two groups. RESULTS:In total, 335 THA patients met inclusion criteria. A greater proportion of patients in the ST group met MSIS criteria preoperatively (30.2%vs.8.3%, p<0.001). Patients in the ST group had higher rates of revision for PJI (28.4%vs.17.5%, p=0.026) and for any indication (48.4%vs.36.7%, p=0.039). MSIS synovial WBC count thresholds were more sensitive in the ST group (90.0%vs.66.7%). There was no difference in culture concordance (67.9%vs.65.9%,p=0.709), though the DT group had a higher rate of negative preoperative cultures followed by positive intraoperative cultures (85.7%vs.41.1%, p=0.047). CONCLUSION/CONCLUSIONS:Our results indicate that approximately one-third of patients have dry hip aspiration, and in these patients cultures are less predictive of intraoperative findings. This suggests that surgeons considering potential PJI after THA should apply extra scrutiny when interpreting negative results in patients who require saline lavage for hip joint aspiration.

INTRODUCTION:Posterior cruciate ligament (PCL) retention may impact a patient's awareness of their artificial joint following primary total knee arthroplasty (pTKA) due to increased proprioception and more native knee kinematics. Therefore, the purpose of this study was to investigate whether cruciate-retaining (CR) or posterior-stabilized (PS) implants influence the Forgotten Joint Score (FJS-12) following pTKA. METHODS:We retrospectively reviewed all patients who underwent pTKA with a CR or PS implant at our institute between October 2017 and March 2021. Of the 6,258 patients identified, 5,587 did not have recorded FJS-12 scores at either three months, one year, or two years postoperatively nor a Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) preoperatively, three months, or one year postoperatively, and these were considered lost to follow up. Thus, a total of 671 cases were identified and subsequently stratified into two cohorts based on whether they received a CR (n=236, 35%) or PS (n=435, 65%) implant. Patients who received PS implants were further divided into constrained (CoN) and non-constrained (NCoN) liner cohorts. Multivariable linear regression analysis was used to compare patient-reported outcome (PRO) scores. RESULTS:There were no significant differences in PRO scores between CR and PS implants at any time point. Patients in the CoN (n=74) cohort had significantly higher FJS-12 scores at one year (CoN: 56.31 + 25.34 vs NCoN: 42.24 + 27.00, p=0.001) and two years (CoN: 58.52 + 33.71 vs NCoN: 46.97 + 27.44, p=0.013) postoperatively compared to patients in the NCoN (n=361) cohort. CONCLUSION:Although our analysis demonstrated significant differences in FJS-12 scores at one and two years postoperatively depending upon the liner constraint, there were no significant differences in FJS-12 scores between CR and PS implants. Therefore, while retention of the PCL does not impact patient awareness of their artificial joint, the level of liner constraint may influence outcomes if the PCL is sacrificed.

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.

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.

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.

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.