Faculty Bibliography

BACKGROUND:In 2015, the healthcare system transitioned from International Classification of Diseases, Ninth Revision (ICD-9) coding to the Tenth Revision (ICD-10). We sought to determine the effect of this change on the reported incidence of complications following total knee arthroplasty (TKA). METHODS:The Humana administrative claims database was queried from 2 years prior to October 1, 2015 (ICD-9 cohort) and for 1 year after this date (ICD-10 cohort) to identify all TKA procedures. Complications occurring within 6 months of surgery were captured using the respective coding systems. Incidence of each complication was compared between cohorts using risk ratios (RR) and 95% confidence intervals. RESULTS:There were 19,009 TKAs in the ICD-10 cohort and 38,172 TKAs in the ICD-9 cohort. The incidence of each complication analyzed was significantly higher in the ICD-9 cohort relative to the ICD-10 cohort. Periprosthetic joint infection occurred in 1.9% vs 1.3% (RR 1.5, 1.3-1.9), loosening in 0.3% vs 0.1% (RR 2.7, 1.8-4.9), periprosthetic fracture in 0.3% vs 0.1% (RR 3.0, 1.6-4.5), and other mechanical complications in 0.7% vs 0.4% (RR 2.0, 1.5-2.5) (P < .05 for all). CONCLUSION/CONCLUSIONS:The transition from ICD-9 to ICD-10 coding has altered the reported incidence of complications following TKA. These results are likely due to the added complexity of ICD-10 which is joint and laterality specific. It is important to understand the differences between coding systems as this data is used for quality initiatives, risk adjustment models, and clinical research. Thoughtful methodology will be necessary when ICD-9 and ICD-10 data are being analyzed simultaneously.

BACKGROUND:Today, biological fixation of uncemented press-fit acetabular components plays an important role in total hip arthroplasty. Long-term stable fixation of these implants depends on the osseointegration of the acetabular cup bone tissue into the acetabular cup implant, and their ability to withstand functional loads. AIM/OBJECTIVE:To compare the strength of bone-implant osseointegration of four types of porous metal implants in normal and osteoporotic bone in rabbits. METHODS:The study was performed in 50 female California rabbits divided into non-ovariectomized (non-OVX) and ovariectomized groups (OVX) at 6 mo of age. Rabbits were sacrificed 8 wk after the implantation of four biomaterials [TTM, CONCELOC, Zimmer Biomet's Trabecular Metal (TANTALUM), and ATLANT] in a 5-mm diameter defect created in the left femur. A biomechanical evaluation of the femur was carried out by testing implant breakout force. The force was gradually increased until complete detachment of the implant from the bone occurred. RESULTS:= 0.001). CONCLUSION/CONCLUSIONS:= 0.001) in healthy and in osteoporotic bone.

BACKGROUND:Obesity is a growing public health concern. This study aims to identify the association of body mass index (BMI) on postoperative Forgotten Joint Score-12 (FJS-12) in patients undergoing primary total hip arthroplasty (THA). METHODS:):<30 (nonobese) and ≥30 (obese). FJS-12 scores were collected postoperatively at 3 months, 1 year, and 2 years. Demographic differences were assessed with chi-square and independent sample t-tests. Mean scores between the groups were compared using multilinear regression analysis, controlling for demographic differences. RESULTS:Of the 2130 patients included, 1378 were nonobese, and 752 were obese. Although obese patients reported lower FJS-12 scores all time periods, there were no statistical differences between the two groups at 3 months (53.61 vs 49.62;P = .689), 1 year (68.11 vs 62.45; P = .349), and 2 years (73.60 vs 65.58; P = .102). A subanalysis comparing patients who were of normal BMI (<25), overweight (25.0-29.9), and obese (≥30) followed a similar inverse trend in scores but showed no statistical differences at all postoperative time points (3m:P = .612,1y:P = .607,2y:P = .253). Mean improvement in FJS-12 scores from 3 months to 1 year (14.50 vs 12.83; P = .041), 1 year to 2 years (5.49 vs 3.13; P = .004), and from 3 months to 2 years (20.00 vs15.96; P < .001) were significantly greater for nonobese patients compared to obese patients. CONCLUSION/CONCLUSIONS:While obesity trended toward lower FJS-12 scores, the differences in scores were not statistically significant compared to nonobese patients. BMI did not influence overall FJS-12 scores; however, obese patients achieved a slightly smaller statistical improvement during the first 2 years, though this may not be clinically significant. LEVEL III EVIDENCE/UNASSIGNED:Retrospective Cohort Study.

Background/UNASSIGNED:An adult reconstruction (AR) fellowship is designed to provide advanced training for a broad range of primary reconstructive and complex knee revision surgeries. This study aims to identify outcome differences between primary total knee arthroplasty (TKA) performed by AR fellowship-trained surgeons and non-AR (NAR) fellowship-trained surgeons. Material and Methods/UNASSIGNED:-tests. Primary outcomes were compared using multilinear regressions, controlling for demographic differences. Results/UNASSIGNED:< .001) scores were significantly higher for the AR cohort but did not exceed the minimal clinically important difference. Conclusion/UNASSIGNED:This study demonstrates significantly shorter surgical times and greater improvements in KOOS, JR and VR-12 PCS scores associated with TKAs performed by AR fellowship-trained surgeons. Level III Evidence/UNASSIGNED:Retrospective Cohort Study.

BACKGROUND:As the Center for Medicare and Medicaid (CMS) moves toward bundled payment plans for total joint arthroplasty (TJA), it becomes necessary to reduce factors that increase cost for an episode of care such as readmissions. The goal of this study is to evaluate the payment for observation stay versus readmission for patients who present to the emergency department. METHODS:A retrospective review from 2014-2019 was conducted identifying all Medicare patients who had a primary, elective TJA and visited the ED within 90 days postoperatively. If a readmission was one midnight or less or had an equivalent diagnosis to an observation stay patient, it was characterized as a readmission that could have qualified as an observation stay. Using our institution's average payment for Medicare readmissions and observations, actual and potential savings were calculated. RESULTS:Sixty-nine out of 523 (13.2%) patients were placed under observation, while 454 (86.8%) patients were readmitted. Eighty-six out of 523 (18.9%) patients qualified for observation status. There was an actual savings of 11.8% by placing patients on observation status and readmission rate was decreased by 13.2%. Savings could have increased by a total of 27.7% and readmissions decreased by a total of 29.6% if all patients who qualified had been placed on observation status. CONCLUSION/CONCLUSIONS:At our institution, the implementation of observation stay has led to a savings of 11.8% and a potential total savings of 27.7%. The rate of readmissions was decreased by 13.2% and had the potential to decrease by a total of 29.6%.

Introduction/UNASSIGNED:Venous thromboembolism (VTE) is a known complication after total knee arthroplasty (TKA) with well-established morbidity, mortality, and significant healthcare expenditure. However, no standard form of prophylaxis against VTE currently exists. Methods/UNASSIGNED:A retrospective review was performed identifying 12,866 TKA cases and post-operative VTE events using either 325 mg aspirin or 81 mg aspirin twice daily (BID). Results/UNASSIGNED:133 VTE cases were diagnosed of the 9413 TKA on 325 mg aspirin BID compared to 8 VTE cases out of 3453 TKA on 81 mg aspirin BID (1.41% vs. 0.23%, p < 0.001). Conclusion/UNASSIGNED:81 mg aspirin BID significantly improved post-operative VTE rates over 325 mg aspirin BID.

Introduction/UNASSIGNED:Improper cup positioning and leg length discrepancy (LLD) are two of the most common errors following total hip arthroplasty (THA) and are associated with potentially significant consequences. Obesity is associated with increased risk of mechanical complications, including dislocations, which may be secondary to cup malposition and failure to restore leg length and offset. 3D Optical Camera computerassisted navigation (CAN) system may reduce the risk of component malposition and LLD with real time intraoperative feedback. The aim of this study was to investigate whether the use of CAN influences acetabular component placement (CP) accuracy and leg length restoration in obese (body mass index(BMI)≥35kg/m 2 ) patients undergoing primary THA. Methods/UNASSIGNED:A multi-center retrospective review was conducted identifying consecutive THA cases with BMI > 35kg/m 2 using CAN (Intellijoint Hip, Waterloo, CA) from 2015-2019. These patients were then matched with patients undergoing conventional THA (control) at a 1:1 ratio according to BMI, American Society of Anesthesiologists score, and gender. TraumaCad™ software (Brainlab, Chicago, IL) was used to measure cup anteversion, inclination, and change (Δ) in LLD between pre- and postoperative radiographic images. The safety target zones used as reference for precision analysis of CP were 15°-30° for anteversion and 30°-50° for inclination. Results/UNASSIGNED:176 patients were included: 88 CAN and 88 control cases. CAN cases were found to have a lower ΔLLD than controls (3.53±2.12mm vs. 5.00±4.05mm; p=0.003). Additionally, more CAN cases fell within the target safe zone than controls (83% vs.60%, p=0.00083). Conclusion/UNASSIGNED:Our findings suggest that the use of a CAN system may be more precise in component placement, and useful in facilitating the successful restoration of preoperative leg length following THA than conventional methodology.

The purpose of this study was to investigate whether preoperative opioid use had any effect on clinical outcomes and patient-reported outcome measures (PROMs) before and after primary, elective total hip arthroplasty (THA). The authors retrospectively reviewed 793 patients who underwent primary THA from November 2018 to March 2020 with available PROMs. Patients were stratified into two groups based on whether or not they were taking opioids preoperatively. Demographics, clinical data, and PROMs (Forgotten Joint Score-12 [FJS-12], Hip disability and Osteoarthritis Outcome Score for Joint Replacement [HOOS, JR], and Veterans RAND 12 [VR-12] Physical Component Score [PCS] and Mental Component Score [MCS]) were collected at various time periods. Demographic differences were assessed with chi-square and independent sample t tests. Clinical data and PROMs were compared using multilinear regressions. Seventy-five (10%) patients were preoperative opioid users and 718 (90%) were not. Preoperative opioid users had a longer stay (1.37 vs 1.07 days; P=.030), a longer surgical time (102.44 vs 90.20 minutes; P=.001), and higher all-cause postoperative emergency department visits (6.7% vs 2.1%; P=.033) compared with patients not taking opioids preoperatively. Preoperative HOOS, JR (46.63 vs 51.26; P=.009), VR-12 PCS (27.79 vs 31.53; P<.001), and VR-12 MCS (46.24 vs 49.33; P=.044) were significantly lower for preoperative opioid users, but 3-month and 1-year postoperative scores were not statistically different. At 3 months and 1 year, FJS-12 scores did not differ significantly. Mean improvement preoperatively to 1 year in HOOS, JR values exceeded the minimal clinically important difference, with preoperative opioid users experiencing a greater improvement (36.50 vs 33.11; P=.008). Preoperative opioid users had a longer stay, a longer surgical time, and higher all-cause emergency department visits compared with preoperatively opioid naïve patients. Although preoperative opioid users reported significantly lower preoperative PROMs, they did not statistically differ postoperatively, which indicates a larger delta improvement and similar benefits following THA. [Orthopedics. 2021;44(2):77-84.].

Cementless fixation in total knee arthroplasty (TKA) offers the potential for biologically active osseointegration and the potential for life-long fixation. With early cementless TKA designs, several design issues were identified related to early failure, particularly with the tibial and patellar components. However, in the recent two decades, with improvements upon the early designs, particularly in porous metal technology as well as improved early biomechanical stability, interest was re-established in cementless TKA. The surgical technique for cementless TKA is more exacting than cemented technique, with an important emphasis on indications, accurate resections, and component alignment. Modern cementless TKA designs have demonstrated excellent early- and mid-term survivorship equivalent to cemented TKA. More long-term studies are needed to study this comparison. While implant cost maybe higher with cementless designs, there is emerging evidence that there may be an overall cost saving with the use of cementless components given the shorter operative time and the savings in the cost of supplies associated with the use of cement. As the population undergoing TKA is becoming younger and more active, interest in the use of cementless implants will likely increase.

Background/UNASSIGNED:In March 2020 elective total hip and knee arthroplasty (THA and TKA) were suspended across the United States in response to the COVID-19 pandemic. We had previously published the results of a survey to the affected patients from 6 institutions. We now present the results of a larger distribution of this survey, through May and June 2020, to electively scheduled patients representing different regions of the United States. Methods/UNASSIGNED:Fifteen centers identified through the AAHKS Research Committee participated in a survey study of THA and TKA patients. Patients scheduled for primary elective THA or TKA but canceled due to the COVID-19 elective surgery stoppage (3/2020-5/2020) were included in the study. Descriptive statistics along with subgroup analysis with Wilcoxon rank were performed. Results/UNASSIGNED:In total, surveys were distributed to 2135 patients and completed by 848 patients (40%) from 15 institutions. Most patients (728/848, 86%) had their surgery postponed or canceled by the surgeon or hospital. Unknown length of surgical delay remained the highest source of anxiety among survey participants. Male patients were more likely to be willing to proceed with surgery in spite of COVID-19. There were minimal regional differences in responses. Only 61 patients (7%) stated they will continue to delay surgery for fear of contracting COVID-19 while in the hospital. Conclusion/UNASSIGNED:Similar to the previous study, the most anxiety-provoking thought was the uncertainty over if and when the canceled joint replacement surgery could be rescheduled. Patients suffering from the daily pain of hip and knee arthritis that have been scheduled for elective arthroplasty remain eager to have their operation as soon as elective surgery is allowed to resume.