Is there variation in utilization of preoperative tests among patients undergoing total hip and knee replacement in the US, and does it affect outcomes? A population-based analysis.

STUDY OBJECTIVE: To describe recent practice patterns of preoperative tests and to examine their association with 90-day all-cause readmissions and length of stay. DESIGN: Retrospective cohort study using the New York Statewide Planning and Research Cooperative System (SPARCS). SETTING: SPARCS from March 1, 2016, to July 1, 2017. PARTICIPANTS: Adults undergoing Total Hip Replacement (THR) or Total Knee Replacement (TKR) had a preoperative screening outpatient visit within two months before their surgery. INTERVENTIONS: Electrocardiogram (EKG), chest X-ray, and seven preoperative laboratory tests (RBCs antibody screen, Prothrombin time (PT) and Thromboplastin time, Metabolic Panel, Complete Blood Count (CBC), Methicillin Resistance Staphylococcus Aureus (MRSA) Nasal DNA probe, Urinalysis, Urine culture) were identified. PRIMARY AND SECONDARY OUTCOME MEASURES: Regression analyses were utilized to determine the association between each preoperative test and two postoperative outcomes (90-day all-cause readmission and length of stay). Regression models adjusted for hospital-level random effects, patient demographics, insurance, hospital TKR, THR surgical volume, and comorbidities. Sensitivity analysis was conducted using the subset of patients with no comorbidities. RESULTS: Fifty-five thousand ninety-nine patients (60% Female, mean age 66.1+/- 9.8 SD) were included. The most common tests were metabolic panel (74.5%), CBC (66.8%), and RBC antibody screen (58.8%). The least common tests were MRSA Nasal DNA probe (13.0%), EKG (11.7%), urine culture (10.7%), and chest X-ray (7.9%). Carrying out MRSA testing, urine culture, and EKG was associated with a lower likelihood of 90-day all-cause readmissions. The length of hospital stay was not associated with carrying out any preoperative tests. Results were similar in the subset with no comorbidities. CONCLUSIONS: Wide variation exists in preoperative tests before THR and TKR. We identified three preoperative tests that may play a role in reducing readmissions. Further investigation is needed to evaluate these findings using more granular clinical data.

Rate of USMLE Step 2 CK Scores Included on Orthopedic Surgery Applications and Associations With Step 1 Score.

Background At present, orthopedic surgery applicants do not universally include Step 2 Clinical Knowledge (Step 2 CK) scores on their applications and current inclusion rates are not yet reported. As Step 1 transitions to pass/fail scoring, we suspect more applicants will include Step 2 CK scores. We sought to identify what percentage of applications currently include Step 2 CK, if applicants who include Step 2 CK (Step 1+CK) score lower on Step 1 than those not including Step 2 CK (Step 1-CK), and what correlations exist between Step 1 and Step 2 CK scores among those who include the scores on their applications. Methodology Applicants to one residency program over two application cycles (2019-2020) were analyzed. The percentage including Step 1 and Step 2 scores was recorded. Step 1 scores were compared between Step 1+CK and Step 1-CK applicants. Differences between Step 2 CK and Step 1 scores were stratified by Step 1 score. Results A total of 1,688 applicants applied to our institution from 2019 to 2020. Of those reporting United States Medical Licensing Examination scores, 1,316/1,660 (79%) reported a Step 2 CK score. Step 1-CK applicants scored higher on Step 1 (250.7 ± 10.9) versus Step 1+CK applicants (244.3 ± 13.1) (p < 0.0001). More applicants who scored lower on Step 1 improved upon their percentile rank between Step 1 and Step 2 CK than those who scored higher on Step 1 (χ2 (8,1316) = 79.1, p < 0.0001). Conclusions From 2019 to 2020, 79% of applicants included Step 2 CK. Lower Step 1 scores were more likely to include Step 2 CK and improve upon their percentile score. It is unclear how Step 1 scoring change will affect current practice.

Use of the Behavior Assessment Tool in 18 Pilot Residency Programs.

BACKGROUND: The purpose of this study was to determine the feasibility and evaluate the effectiveness of the American Board of Orthopaedic Surgery Behavior Tool (ABOSBT) for measuring professionalism. METHODS: Through collaboration between the American Board of Orthopaedic Surgery and American Orthopaedic Association's Council of Residency Directors, 18 residency programs piloted the use of the ABOSBT. Residents requested assessments from faculty at the end of their clinical rotations, and a 360° request was performed near the end of the academic year. Program Directors (PDs) rated individual resident professionalism (based on historical observation) at the outset of the study, for comparison to the ABOSBT results. RESULTS: Nine thousand eight hundred ninety-two evaluations were completed using the ABOSBT for 449 different residents by 1,012 evaluators. 97.6% of all evaluations were scored level 4 or 5 (high levels of professional behavior) across all of the 5 domains. In total, 2.4% of all evaluations scored level 3 or below reflecting poorer performance. Of 431 residents, the ABOSBT identified 26 of 32 residents who were low performers (2 or more < level 3 scores in a domain) and who also scored "below expectations" by the PD at the start of the pilot project (81% sensitivity and 57% specificity), including 13 of these residents scoring poorly in all 5 domains. Evaluators found the ABOSBT was easy to use (96%) and that it was an effective tool to assess resident professional behavior (81%). CONCLUSIONS: The ABOSBT was able to identify 2.4% low score evaluations (

Resident Selection in the Wake of United States Medical Licensing Examination Step 1 Transition to Pass/Fail Scoring.

INTRODUCTION: The numeric score for the United States Medical Licensing Examination Step 1 is one of the only universal, objective, scaled criteria for comparing the many students who apply to orthopaedic surgery residency. However, on February 12, 2020, it was announced that Step 1 would be transitioning to pass/fail scoring. The purpose of this study was to (1) determine the most important factors used for interview and resident selection after this change and (2) to assess how these factors have changed compared with a previous report on resident selection. METHODS: A survey was distributed to the program directors (PDs) of all 179 orthopaedic surgery programs accredited by the Accreditation Council for Graduate Medical Education. Questions focused on current resident selection practices and the impact of the Step 1 score transition on expected future practices. RESULTS: A total of 78 PDs (44%) responded to the survey. Over half of PDs (59%) responded that United States Medical Licensing Examination Step 2 clinical knowledge (CK) score is the factor that will increase most in importance after Step 1 transitions to pass/fail, and 90% will encourage applicants to include their Step 2 CK score on their applications. The factors rated most important in resident selection from zero to 10 were subinternship performance (9.05), various aspects of interview performance (7.49 to 9.01), rank in medical school (7.95), letters of recommendation (7.90), and Step 2 CK score (7.27). Compared with a 2002 report, performance on manual skills testing, subinternship performance, published research, letters of recommendations, and telephone call on applicants' behalf showed notable increases in importance. DISCUSSION: As Step 2 CK is expected to become more important in the residency application process, current applicant stress on Step 1 scores may simply move to Step 2 CK scores. Performance on subinternships will remain a critical aspect of residency application, as it was viewed as the most important resident selection factor and has grown in importance compared with a previous report.

Factors Influencing Subspecialty Choice of Orthopedic Residents: Effect of Gender, Year in Residency, and Presumptive Subspecialty.

Background: Subspecialty training is a common part of orthopedic surgical training. The factors which influence resident subspecialty choice have important residency design and workforce implications. Our objective was to present survey data gathered from orthopedic residents regarding their fellowship plans and relative importance of factors which influence those plans. Methods: An anonymous online survey tool was developed and distributed to orthopedic residents through their program directors at academic institutions across the country with orthopedic surgery residency programs. Results: 227 residents completed the survey. 97% planned to pursue fellowship training after residency. The most common presumptive subspecialties were sports (29.7%), joints (17.3%) and shoulder/ elbow (12.8%). The majority of senior residents (57%) reported that their subspecialty choice had changed during residency. When making their choice of subspecialty, residents were most influenced by their experiences working on the subspecialty service in question, their experiences working with a mentor, and intellectual interest. The factors influencing their choice were affected by gender, residency year and presumptive subspecialty. Conclusions: The most critical factors influencing subspecialty choice of orthopedic residents included experiences in rotations as a resident, intellectual interest and mentors in certain subspecialties. Factors influencing subspecialty choice changes over the course of residency and differ between male and female residents. This information may be useful for residency design, mentorship structuring, career counseling and for addressing subspecialty surpluses or shortages which arise in the future.Level of Evidence: IV.

Anterior versus posterior approach total hip arthroplasty: patient-reported and functional outcomes in the early postoperative period.

PURPOSE: Direct anterior approach total hip arthroplasty (DA THA) has been reported to improve early outcomes compared to posterior approach THA up to 6 weeks postoperatively. Limited weekly outcomes data are available prior to 6 weeks. We evaluate outcomes including when patients first drive a car, leave home, and discontinue their assist device. METHODS: Patients undergoing THA for primary osteoarthritis were prospectively enrolled. Outcomes data were collected preoperatively and postoperatively at weekly intervals for 6 weeks. RESULTS: 111 patients (55 DA and 56 posterior approach) were enrolled. There was no significant difference (p > 0.05) in pre-surgical Patient-Reported Outcomes Measurement Information System (PROMIS) scores or modified Harris Hip Score (mHHS).Postoperatively, the DA THA group had decreased length of stay (p = 0.0002) and increased distance walked on postoperative day 1 and 2 (p = 0.011, p = 0.0004). The DA group had lower pain scores (p < 0.05) and required less day 1 and total narcotics (p = 0.029, p = 0.01). The DA cohort had improved PROMIS Physical Function scores and mHHS up to 5 weeks postoperatively. DA patients discontinued their assistive device 8 days earlier (p = 0.01), left home 3 days earlier (p = 0.001), and drove a car 5 days earlier (p = 0.01). CONCLUSIONS: Patients undergoing DA THA discontinued their assistive device, left their home, and drove a car sooner than posterior approach patients. We found improvement in physical function with DA, and it persisted up to 5 weeks postoperatively. Furthermore, DA patients had significantly shorter length of stay, improved mobilisation, decreased narcotic requirements and improved inpatient pain scores compared to posterior approach THA. Future randomised controlled study should be performed to minimise the biases inherent in this study methodology and confirm the results.

Single-Use Custom Instrumentation in Total Knee Arthroplasty: Effect on In-Hospital Complications, Length of Stay, and Discharge Disposition.

Total knee arthroplasty (TKA) is a quality surgical intervention with rapidly increasing use. This growth has brought with it a host of new technologies, including custom instrumentation (CI). With the current emphasis on value-based health care, the clinical benefit of CI TKA must be evaluated. The goal of this study was to compare CI and conventional TKA regarding multiple quality metrics, in-hospital complications, length of stay, and discharge destination. The authors propensity score matched 231 conventional TKAs to 231 consecutive CI TKAs for age, sex, and body mass index. Preoperative risk factors analyzed were age, sex, body mass index, and preoperative hemoglobin. Perioperative factors included transfusion rate, hemoglobin drop, hemovac output, operative time, length of stay, discharge disposition, deep venous thrombosis and pulmonary embolism rates, and in-hospital vital sign data. There were no differences in preoperative demographics between groups. Postoperatively, there was no difference between conventional and CI TKA in operative time, transfusion rate, discharge hemoglobin, length of stay, discharge disposition, or in-hospital venous thromboembolism rates. In the conventional and CI groups, length of stay was 2.6 and 2.5 days (P=.43) and discharge disposition was 82% home and 83% home (P=.90), respectively. Although CI TKA is commonly implemented, in this analysis, compared with conventional TKA, it was not associated with any difference in length of stay, discharge disposition, operative time, transfusion rate, or in-hospital complications. [Orthopedics. 2019; 42(5):299-303.].

Medially-stabilized total knee arthroplasty does not alter knee laxity and balance in cadaveric knees.

Instability after total knee arthroplasty (TKA) can lead to suboptimal outcomes and revision surgery. Medially-stabilized implants aim to more closely replicate normal knee motion than other implants following TKA, but no study has investigated knee laxity (motion under applied loads) and balance (i.e., difference in varus/valgus motion under load) following medially-stabilized TKA. The primary purposes of this study were to investigate how medially-stabilized implants change knee laxity in non-arthritic, cadaveric knees, and if it produces a balanced knee after TKA. Force-displacement data were collected on 18 non-arthritic cadaveric knees before and after arthroplasty using medially-stabilized implants. Varus-valgus and anterior-posterior laxity and varus-valgus balance were compared between native and medially-stabilized knees at 0°, 20°, 60°, and 90° under three different loading conditions. Varus-valgus and anterior-posterior laxities were not different between native and medially-stabilized knees under most testing conditions (p ≥ 0.068), but differences of approximately 2° less varus-valgus laxity at 20° of flexion and 4 mm more anterior-posterior laxity at 90° were present from native laxities (p < 0.017) Medially-stabilized implant balance had ≤1.5° varus bias at all flexion angles. Future studies should confirm if the consistent laxity afforded by the medially-stabilized implant is associated with better and more predictable postoperative outcomes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:335-349, 2019.

Time-to-Surgery for Definitive Fixation of Hip Fractures: A Look at Outcomes Based Upon Delay.

The morbidity and mortality after hip fracture in the elderly are influenced by non-modifiable comorbidities. Time-to-surgery is a modifiable factor that may play a role in postoperative morbidity. This study investigates the outcomes and complications in the elderly hip fracture surgery as a function of time-to-surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program data from 2011 to 2012, a study population was generated using the Current Procedural Terminology codes for percutaneous or open treatment of femoral neck fractures (27235, 27236) and fixation with a screw and side plate or intramedullary fixation (27244, 27245) for peritrochanteric fractures. Three time-to-surgery groups (<24 hours to surgical intervention, 24-48 hours, and >48 hours) were created and matched for surgery type, sex, age, and American Society of Anesthesiologists class. Time-to-surgery was then studied for its effect on the post-surgical outcomes using the adjusted regression modeling. A study population of 6036 hip fractures was created, and 2012 patients were assigned to each matched time-to-surgery group. The unadjusted models showed that the earlier surgical intervention groups (<24 hours and 24-48 hours) exhibited a lower overall complication rate (P = .034) compared with the group waiting for surgery >48 hours. The unadjusted mortality rates increased with delay to surgical intervention (P = .039). Time-to-surgery caused no effect on the return to the operating room rate (P = .554) nor readmission rate (P = .285). Compared with other time-to-surgeries, the time-to-surgery of >48 hours was associated with prolonged total hospital length of stay (10.9 days) (P < .001) and a longer surgery-to-discharge time (hazard ratio, 95% confidence interval: 0.74, 0.69-0.79) (P < .001). Adjusted analyses showed no time-to-surgery related difference in complications (P = .143) but presented an increase in the total length of stay (P < .001) and surgery-to-discharge time (P < .001). Timeliness of surgical intervention in a comorbidity-adjusted population of elderly hip fracture patients causes no effect on the overall complications, readmissions, nor 30-day mortality. However, time-to-surgery of >48 hours is associated with costly increase in the total length of stay, including an increased post-surgery-to-discharge time.

Variation in tibial tuberosity lateralization and distance from the tibiofemoral joint line: An anatomic study.

BACKGROUND: To describe variation in tibial tuberosity position in a normal adult population and inter-rater reliability of measurements of tibial tuberosity position. METHODS: Surface models of 161 proximal tibia specimens (83 female, 78 male; 80 black, 81 white; age 28.7years, SD 7.5) were created with a three-dimensional laser scanner. Percent lateralization, tuberosity-eminence angle, and distance from joint surface were measured for each specimen. Variation in tuberosity position by sex, race, age, height, and BMI was calculated. Multivariate regression was used to assess for demographic factors independently associated with tuberosity positioning. RESULTS: Mean percent lateralization was 57.9% (SD 2.4, range 52.4-64.9%). Tuberosity-eminence angle mean was 11.03° (SD 2.8, range 0-18.7°). Percent lateralization and tuberosity-eminence angle were not influenced by sex, race, age, height or, BMI (p>0.05). Mean tuberosity distance from joint surface was 29.2mm (SD 3.5, range 16.6-38.6mm) and larger in males than females (30.7mm (SD 2.9), 27.6mm (SD 3.3); p<0.001). Tuberosity distance from joint surface increased 0.18mm on average per 1.0cm increase in height (p<0.001). Inter-rater reliability was high for distance from joint surface (Cronbach alpha=0.99) and percent lateralization. CONCLUSIONS: Tibial tuberosity percent lateralization falls in a narrow range for individuals, whereas tuberosity-eminence angle and distance from joint line are more variable. Inter-rater reliability is high for percent lateralization and distance for the joint surface. Distance of tibial tuberosity from joint surface is associated with sex and height.

The Effect of Smoking on Thirty-Day Postoperative Complications After Total Joint Arthroplasty: A Propensity Score-Matched Analysis.

BACKGROUND: Total joint arthroplasty (TJA) is a highly successful treatment, but is burdensome to the national healthcare budget. National quality initiatives seek to reduce costly complications. Smoking's role in perioperative complication after TJA is less well known. This study aims to identify smoking's independent contribution to the risk of short-term complication after TJA. METHODS: All patients undergoing primary TJA between 2011 and 2012 were selected from the American College of Surgeon's National Surgical Quality Improvement Program's database. Outcomes of interest included rates of readmission, reoperation, mortality, surgical complications, and medical complications. To eliminate confounders between smokers and nonsmokers, a propensity score was used to generate a 1:1 match between groups. RESULTS: A total of 1251 smokers undergoing TJA met inclusion criteria. Smokers in the combined total hip and knee arthroplasty cohort had higher 30-day readmission (4.8% vs 3.2%, P = .041), were more likely to have a surgical complication (odds ratio 1.84, 95% confidence interval 1.21-2.80), and had a higher rate of deep surgical site infection (SSI) (1.1% vs 0.2%, P = .007). Analysis of total hip arthroplasty only revealed that smokers had higher rates of deep SSI (1.3% vs 0.2%, P = .038) and higher readmission rate (4.3% vs 2.2%, P = .034). Analysis of total knee arthroplasty only revealed greater surgical complications (2.8% vs 1.2%, P = .048) and superficial SSI (1.8% vs 0.2%, P = .002) in smokers. CONCLUSION: Smoking in TJA is associated with higher rates of SSI, surgical complications, and readmission.

The Lawrence D. Dorr Surgical Techniques & Technologies Award: Differences in Postoperative Outcomes Between Total Hip Arthroplasty for Fracture vs Osteoarthritis.

BACKGROUND: Hip fracture is an increasingly common expanded indication for total hip arthroplasty (THA) and warrants outcome analysis so as to best inform risk assessment models, public reporting of outcome, and value-based reimbursement schemes. METHODS: The National Surgical Quality Improvement Program data file from 2011 to 2014 was used to identify all patients undergoing THA via current procedural terminology code 27130. Propensity score matching in a 1:5 fashion was used to compare 2 cohorts: THA for osteoarthritis and THA for fracture. Primary outcomes included Centers for Medicare and Medicaid Services (CMS) reportable complications, unplanned readmission, postsurgical length of stay, and discharge destination. χ2 tests for categorical variables and Student t test for continuous variables were used to compare the 2 cohorts and adjusted linear regression analysis used to determine the association between hip fracture and THA outcomes of interest. RESULTS: A total of 58,302 patients underwent elective THA for osteoarthritis and 1580 patients underwent THA for hip fracture. Rates of CMS-reported complications (4.0% vs 10.7%; P < .001), non-homebound discharge (39.8% vs 64.7%; P < .001), readmission (4.7% vs 8.0%; P < .001), and mean days of postsurgical hospital stay (3.2 vs 4.4; P < .001) were greater in the hip fracture cohort. THA for hip fracture was significantly associated with increased risk of CMS-reportable complications (odds ratio [OR], 2.67; 95% confidence interval [CI], 2.17-3.28), non-homebound discharge (OR, 1.73; 95% CI, 1.39-2.15), and readmission (OR, 2.78; 95% CI, 2.46-3.12). CONCLUSION: Our findings support recent advocacy for the exclusion of THA for fracture from THA bundled pricing methodology and public reporting of outcomes.

Relationships between varus-valgus laxity of the severely osteoarthritic knee and gait, instability, clinical performance, and function.

Increased varus-valgus laxity has been reported in individuals with knee osteoarthritis (OA) compared to controls. However, the majority of previous investigations may not report truly passive joint laxity, as their tests have been performed on conscious participants who could be guarding against motion with muscle contraction during laxity evaluation. The purpose of this study was to investigate how a measure of passive knee laxity, recorded when the participant is under anesthesia, is related to varus-valgus excursion during gait, clinical measures of performance, perceived instability, and self-reported function in participants with severe knee OA. We assessed passive varus-valgus knee laxity in 29 participants (30 knees) with severe OA, as they underwent total knee arthroplasty (TKA). Participants also completed gait analysis, clinical assessment of performance (6-min walk (6 MW), stair climbing test (SCT), isometric knee strength), and self-reported measures of function (perceived instability, Knee injury, and Osteoarthritis Outcome Score (KOOS) a median of 18 days before the TKA procedure. We observed that greater passive varus-valgus laxity was associated with greater varus-valgus excursion during gait (R2 = 0.34, p = 0.002). Significant associations were also observed between greater laxity and greater isometric knee extension strength (p = 0.014), farther 6 MW distance (p = 0.033) and shorter SCT time (p = 0.046). No relationship was observed between passive varus-valgus laxity and isometric knee flexion strength, perceived instability, or any KOOS subscale. The conflicting associations between laxity, frontal excursion during gait, and functional performance suggest a complex relationship between laxity and knee cartilage health, clinical performance, and self-reported function that merits further study. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1644-1652, 2017.

The Interaction of Obesity and Metabolic Syndrome in Determining Risk of Complication Following Total Joint Arthroplasty.

BACKGROUND: The arthroplasty population is increasingly comorbid, and current quality improvement initiatives demand accurate risk stratification. Metabolic syndrome (MetS) has been identified as a risk factor for adverse events after arthroplasty; however, its interaction with obesity in contributing to risk is unclear. METHODS: A retrospective analysis of all Medicare patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at a single institution from 2009 to 2013 investigated the interaction between MetS, body mass index (BMI), and risk for Centers for Medicare and Medicaid Services (CMS)-reportable complications, readmission, and discharge disposition. RESULTS: A total of 1462 patients (942 TKA, 538 THA) were included, of which 16.2% had MetS. Regression analysis found that MetS was significantly related to risk of CMS complications (odds ratio [OR] = 1.96, 95% confidence interval [CI] 1.16-3.31, P = .012) and nonhome discharge (OR = 1.78, 95% CI 1.39-2.27, P < .001), but not readmission (OR = 1.23, 95% CI 0.7-2.18, P = .485). Within the MetS cohort, increasing BMI was not associated with increasing complications (P = .726) or readmissions (P = .206) but was associated with nonhome discharge (OR = 1.191 per unit increase in BMI, 95% CI 1.038-1.246, P = .001). CONCLUSION: MetS increases risk for CMS-reportable complications and nonhome discharge disposition after THA and TKA regardless of BMI. Obesity is of less value than MetS in assessing overall risk for complication after THA and TKA.

Improving outcomes in total knee arthroplasty-do navigation or customized implants have a role?

Modern total knee arthroplasty is effective at treating the pain and disability associated with osteoarthritis. The number of total knee replacements done in the USA continues to increase. Despite the great care taken during all of these procedures, some patients remain dissatisfied with their outcome. While this dissatisfaction is likely multifactorial, malalignment of the prosthetic components is a major cause of postoperative complications. A neutral mechanical axis plus or minus 3° is felt to have a positive impact on the survivorship of the prosthesis. Conventional instrumentation has been shown to have a significant number of total knee replacements that lie well outside a neutral coronal alignment. With that in mind, significant effort has been placed into the development of technology to improve the overall alignment of the prosthesis. In order to reduce the number of outliers, several companies have developed cost-effective systems to aid the surgeon in achieving a more predictably aligned prosthesis in all three planes. We will review the literature that is available regarding several of these tools to examine if navigation or custom guides improve outcomes in total knee arthroplasty. Our review supports that while both navigation and custom implants guides seem to be a cost effective way to achieve a predictable mechanical alignment of a total knee prosthesis therefore reducing the number of outliers, the cost may be increased operative times with no perceived difference in patient satisfaction with navigation custom guides.

Inter-Rater and Intra-Rater Repeatability and Reliability of EOS 3-Dimensional Imaging Analysis Software.

BACKGROUND: Quantifying ideal component position for the acetabulum and stem during total hip arthroplasty (THA) has been described by many methods. A new imaging method using low-dose digital stereoradiography, the EOS imaging system, is a biplanar low-dose X-ray system that allows for 3-dimensional modeling of lower limbs and semiautomated measurement of pelvic parameters and implant alignment. METHODS: Twenty-five patients who underwent primary THA by a single surgeon between October 2014 and December 2014 were retrospectively selected. Only patients with unilateral THA without associated spine pathologies were included, totaling 16 right hips and 9 left hips. There were 8 men and 17 women in the cohort, with a mean age of 67 years (range, 53-82). Three individuals performed measurements of pelvic parameters and implant alignment on 3 separate occasions. An interclass correlation of >0.75 was accepted as evidence of excellent agreement and a confirmation of measurement reliability. RESULTS: Before reviewing patient radiographs, 4 pelvic phantom models were analyzed using the EOS 3-dimensional software to verify accuracy. All anatomic and implant measurements performed by the 3 independent reviewers showed interobserver and intraobserver agreement with interclass correlation >0.75. CONCLUSION: Three-dimensional modeling of hip implants with the EOS imaging system is a reasonable option for the evaluation of component position after THA.

Estimating patient-specific soft-tissue properties in a TKA knee.

Surgical technique is one factor that has been identified as critical to success of total knee arthroplasty. Researchers have shown that computer simulations can aid in determining how decisions in the operating room generally affect post-operative outcomes. However, to use simulations to make clinically relevant predictions about knee forces and motions for a specific total knee patient, patient-specific models are needed. This study introduces a methodology for estimating knee soft-tissue properties of an individual total knee patient. A custom surgical navigation system and stability device were used to measure the force-displacement relationship of the knee. Soft-tissue properties were estimated using a parameter optimization that matched simulated tibiofemoral kinematics with experimental tibiofemoral kinematics. Simulations using optimized ligament properties had an average root mean square error of 3.5° across all tests while simulations using generic ligament properties taken from literature had an average root mean square error of 8.4°. Specimens showed large variability among ligament properties regardless of similarities in prosthetic component alignment and measured knee laxity. These results demonstrate the importance of soft-tissue properties in determining knee stability, and suggest that to make clinically relevant predictions of post-operative knee motions and forces using computer simulations, patient-specific soft-tissue properties are needed.

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Knee and Hip Arthroplasty?

Accurate risk stratification of patients undergoing total hip (THA) and knee (TKA) arthroplasty is essential in the highly scrutinized world of pay-for-performance, value-driven healthcare. We assessed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator's ability to predict 30-day complications using 1066 publicly-reported Medicare patients undergoing primary THA or TKA. Risk estimates were significantly associated with complications in the categories of any complication (P = .005), cardiac complication (P < .001), pneumonia (P < .001) and discharge to skilled nursing facility (P < .001). However, predictability of complication occurrence was poor for all complications assessed. To facilitate the equitable provision and reimbursement of patient care, further research is needed to develop accurate risk stratification tools in TKA and THA surgery.

The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty.

Hip and knee arthroplasty (THA, TKA) are safe, effective procedures with reliable, reproducible outcomes. We aim to investigate obesity's effect on complications following arthroplasty surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program database, 13,250 subjects were stratified into 5 groups based on BMI and matched for gender, age, surgery type and ASA class. Matched, multivariable generalized linear models adjusting for demographics and comorbidities demonstrated an association between elevated BMI and overall (P<0.001), medical (P=0.005), surgical complications (P<0.001), including superficial (P=0.019) and deep wound infection (P=0.040), return to OR (P=0.016) and time from OR to discharge (P=0.003). Elevated BMI increases risk for post-operative complications following total joint arthroplasty.