ACL substitution may improve kinematics of PCL-retaining total knee arthroplasty.

PURPOSE: One of the key factors responsible for altered kinematics and joint stability following contemporary total knee arthroplasty (TKA) is resection of the anterior cruciate ligament (ACL). However, ACL retention can present several technical challenges, and in some cases may not be viable due to an absent or nonfunctional ACL. Therefore, the goal of this research was to investigate whether substitution of the ACL through an anterior post mechanism could improve kinematic deficits of contemporary posterior cruciate ligament (PCL) retaining implants. METHODS: Kinematic analysis of different implant types was done using KneeSIM, a previously established dynamic simulation tool. Walking, stair-ascent, chair-sit, and deep knee bend were simulated for an ACL-substituting (PCL-retaining) design, a bi-cruciate-retaining and ACL-sacrificing (PCL-retaining) implant, as well as the native knee. The motion of the femoral condyles relative to the tibia was recorded for kinematic comparisons. RESULTS: The ACL-substituting and ACL-retaining implants provided similar kinematic improvements over the ACL-sacrificing implant, by reducing posterior femoral shift in extension and preventing paradoxical anterior sliding. During all simulated activities, the ACL-sacrificing implant showed between 7 and 8 mm of posterior shift in extension in contrast to the ACL-retaining implant and the ACL-substituting design, which showed overall kinematic trends similar to the native knee. CONCLUSION: The absence of ACL function has been linked to abnormal kinematics and joint stability in patients with contemporary TKA. ACL-substituting implants could be a valuable treatment option capable of overcoming the limitations of contemporary TKA, particularly when retaining the native ACL is not feasible or is challenging.

Cadaver-Specific Models for Finite-Element Analysis of Iliopsoas Impingement in Dual-Mobility Hip Implants.

BACKGROUND: Joint dislocation is a major cause of failure in total hip arthroplasty. Dual-mobility implants provide a femoral head diameter that can match the native hip size for greater stability against dislocation. However, such large heads are prone to impingement against surrounding soft tissues. To address this concern, the concept of an anatomically contoured dual-mobility implant was evaluated using cadaver-specific finite-element analysis (FEA). METHODS: The stiffness of 10 iliopsoas tendons was measured and also 3D bone models, contact pressure, and iliopsoas tendon stress were evaluated for 2 implant designs according to a previous cadaveric experiment. The iliopsoas interaction with an anatomically contoured and conventional dual-mobility implant was analyzed throughout hip flexion. RESULTS: The tensile test of cadaveric iliopsoas tendons revealed an average linear stiffness of 339.4 N/mm, which was used as an input for the FEA. Tendon-liner contact pressure and tendon von Mises stress decreased with increasing hip flexion for both implants. Average contact pressure and von Mises stresses were lower in the anatomically contoured design compared with the conventional implant across all specimens and hip flexion angles. CONCLUSIONS: This study was built upon a previous cadaver study showing reduced tenting of the iliopsoas tendon for an anatomically contoured design compared with a conventional dual-mobility implant. The present cadaver-specific FEA study found reduced tendon-liner contact pressure and tendon stresses with contoured dual-mobility liners. Anatomical contoured design may be a solution to avoid anterior soft-tissue impingement when using hip prostheses with large femoral heads.

Use of 360° Feedback to Develop Physician Leaders in Orthopaedic Surgery.

Twelve service chiefs participated in 360° feedback surveys and coaching as part of a departmental leadership development activity. Changes in the means of both composite survey scores and individual behavioral item scores over time were evaluated with paired t tests. Agreement between self-rating and rating of others was evaluated with unpaired t tests. There was a nonsignificant change in overall behavioral performance (composite scores) for the physician leaders (n D 12) from baseline [mean (M) D 68.7, standard deviation (SD) D 16.9] to 1-year follow-up (M D 73.1, SD D 11.4), but the performance of four of the leaders with the lowest scores improved substantially. There was a significant improvement in "identifies mistakes respectfully" when comparing baseline to 1-year follow-up. Ten behaviors were identified as improvement opportunities and nine behaviors were identified as behavioral strengths at baseline. Surgeon leaders were in agreement with others' ratings on 68% of behaviors, underestimated 20% of behaviors, and overestimated 13% of behaviors. (Journal of Surgical Orthopaedic Advances 27(2):85-91, 2018).

Unsuspected Malignancies in Routine Femoral Head Histopathologic Examination During Primary Total Hip Arthroplasty: Cost-Effectiveness Analysis.

BACKGROUND: Routine femoral head histopathology during primary total hip arthroplasty (THA) has been recently reported as a potentially useful screening tool for bone- and bone marrow-associated malignancies. However, cost-effectiveness of routine histopathology during THA remains unclear due to low prevalence of significant medical findings which alter patient management. The aim of this study was to evaluate the cost-effectiveness of routine histopathology in diagnosing unsuspected malignancy in patients undergoing primary THA. METHODS: From 1993 to 2011, we retrospectively analyzed routine histopathologic findings of 3200 femoral head specimens from 2725 patients that underwent primary THA. Preoperative and postoperative diagnoses were classified into concordant (clinical diagnosis concurred with pathologic diagnosis), discrepant (differing diagnosis with no resultant impact on patient management), and discordant (differing diagnosis with subsequent change in patient management). Cost-effectiveness analysis was performed using the incremental cost-utility ratio. RESULTS: A total of 3055 of 3200 pathologic samples were concordant with the preoperative diagnosis (95.4%), 140 of 3200 were discrepant (4.4%), and 5 of 3200 were discordant (0.2%). Routine histopathology revealed 1 unsuspected malignancy out of 640 (5 of 3200) femoral heads. The total cost of histopathologic screening was $614,664.80. The average cost to identify a discrepant case was $4390.46, and the cost to identify a discordant case was $122,932.96. The incremental cost-utility ratio was $49,569.74 per quality-adjusted life year (QALY) gained. CONCLUSION: Our study indicates routine femoral head histopathology may be cost-effective in diagnosing unsuspected malignancy at $49,569.74/QALY gained (less than World Health Organization recommended threshold $159,000/QALY gained), providing useful clinical information for surgeons considering the value of routine femoral head histopathology in patients undergoing THA.

Short-term Risk of Revision THA in the Medicare Population Has Not Improved With Time.

INTRODUCTION: Advances in surgical technique, implant design, and clinical care pathways have resulted in higher expectations for improved clinical outcomes after primary THA; however, despite these advances, it is unclear whether the risk of revision THA actually has decreased with time. Understanding trends in short- and mid-term risks of revision will be helpful in directing clinical, research, and policy efforts to improve THA outcomes. QUESTION/PURPOSES: We therefore asked (1) whether there have been changes in overall short- and mid-term risks of revision THA among patients in the Medicare population who underwent primary THA between 1998 and 2010; and (2) whether there are different demographic factors associated with short- and mid- term risks of revision THA. METHODS: Using the Medicare 5% national sample database, patients who underwent primary THA between 1998 and 2010 followed by subsequent revision through 2011 were identified by ICD-9-CM procedure codes 81.51 and 81.53/80.05/00.70-00.73, respectively. This dataset included a random sample of Medicare beneficiaries based on their social security number. Only patients with minimum 1-year followup after primary THA were included in our analysis. A total of 64,260 patients who underwent primary THA were identified from the 1998 to 2010 Medicare 5% dataset. Eighty-eight percent of the patients had 1-year followup providing a final study cohort of 56,700 patients. The risk of revision was evaluated at 1, 3, 5, and 7 years. Multivariate Cox regression was used to evaluate temporal trends in revision risk using two methods to account for time effects with periods 1998 to 2002, 2003 to 2007, and 2008 to 2010 for the index year of primary THA, and individual year of index of primary THA as independent variables. The analysis adjusted for patient age, sex, race, census region, Charlson score, and socioeconomic status. RESULTS: The 7-year crude risk of revision THA declined from 7.10% in 1998 to 2002 to 6.09% in 2008 to 2010, representing a 14.4% overall reduction in adjusted risk of revision (p = 0.0058; 95% CI, 4.4%-23%). Similarly, the 5-year crude risk of revision THA declined from 5.96% in 1998 to 2002 to 5.11% in 2008 to 2010, representing a 14.2% overall reduction in adjusted risk of revision (p = 0.0069; 95% CI, 4.1%-23%). However, the adjusted risk of revision THA at 3 years was not different from 1998 to 2002 (4.70%) and 2008 to 2010 (4.03%; p = 0.1176). Similarly, the adjusted risk of revision at 1 year did not differ from 1998 to 2002 (2.83%) and 2008 to 2010 (2.42%; p = 0.3386). Patients with more comorbidities had a greater adjusted risk of revision (p < 0.001) at all times: 94% (95% CI, 58%-138%) and 56% (95% CI, 33%-84%) at 1 year and 7 years, respectively, for Charlson score of 5+ vs 0). CONCLUSIONS: Although the mid-term (5 and 7 years) risk of revision THA has decreased during the past 14 years among Medicare beneficiaries who underwent primary THA, the short-term risk has not. These findings suggest that greater clinical, research, and policy emphasis is needed to identify potentially avoidable causes of early failure after primary THA in patients in the Medicare population, and multistakeholder solutions are needed to optimize short-term outcomes. LEVEL OF EVIDENCE: Level III, therapeutic study.

Can Robot-Assisted Unicompartmental Knee Arthroplasty Be Cost-Effective? A Markov Decision Analysis.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is a treatment option for single-compartment knee osteoarthritis. Robotic assistance may improve survival rates of UKA, but the cost-effectiveness of robot-assisted UKA is unknown. The purpose of this study was to delineate the revision rate, hospital volume, and robotic system costs for which this technology would be cost-effective. METHODS: We created a Markov decision analysis to evaluate the costs, outcomes, and incremental cost-effectiveness of robot-assisted UKA in 64-year-old patients with end-stage unicompartmental knee osteoarthritis. RESULTS: Robot-assisted UKA was more costly than traditional UKA, but offered a slightly better outcome with 0.06 additional quality-adjusted life-years at an incremental cost of $47,180 per quality-adjusted life-years, given a case volume of 100 cases annually. The system was cost-effective when case volume exceeded 94 cases per year, 2-year failure rates were below 1.2%, and total system costs were <$1.426 million. CONCLUSION: Robot-assisted UKA is cost-effective compared with traditional UKA when annual case volume exceeds 94 cases per year. It is not cost-effective at low-volume or medium-volume arthroplasty centers.

Does "6-Clicks" Day 1 Postoperative Mobility Score Predict Discharge Disposition After Total Hip and Knee Arthroplasties?

BACKGROUND: The use of inpatient rehabilitation services after total joint arthroplasty (TJA) is an important driver of episode-of-care costs. We determined the utility of a new standardized instrument collected during the immediate postoperative period, the Activity Measure for Post-Acute Care (AM-PAC) "6-Clicks" Mobility score, in predicting discharge disposition after TJA and its accuracy in estimating prolonged hospital stay, readmissions, and emergency department (ED) visits. METHODS: Using our institutional database, we retrospectively reviewed 744 patients undergoing primary total hip (40%) or knee (60%) arthroplasty for osteoarthritis during 2014. The AM-PAC Mobility score was prospectively collected by physical therapists within 24 hours of surgery. We constructed 2 multivariable logistic regression models for each study outcome: (1) a base model containing age, sex, Charlson Comorbidity Index, and procedure type and (2) the AM-PAC model including the aforementioned variables and this score. The predictive performance of these models was assessed and compared using the area under the receiver operating characteristic (AUC) curve. RESULTS: The AM-PAC model provided better prediction of discharge disposition (AUC = 0.777) than the base model (AUC = 0.716; 22% relative improvement). Although the AM-PAC model performed 32% and 27% better than the base model in estimating prolonged hospital stay and ED visits, the model's predictive performance was poor (prolonged stay: AUC = 0.639; ED visit: AUC = 0.658). The AM-PAC model also showed poor discrimination of readmissions (AUC = 0.657), and there was no relative improvement in predictive performance compared to that of the base model. CONCLUSION: The AM-PAC "6-Clicks" Mobility score is a valid, simple tool for predicting discharge disposition after TJA.

Thirteen-Year Evaluation of Highly Cross-Linked Polyethylene Articulating With Either 28-mm or 36-mm Femoral Heads Using Radiostereometric Analysis and Computerized Tomography.

BACKGROUND: The objective of this 13-year prospective evaluation of highly cross-linked ultra high molecular weight polyethylene (HXLPE) was to (1) assess the long-term wear of HXLPE articulating with 2 femoral head sizes using radiostereometric analysis (RSA) and to (2) determine if osteolysis is a concern with this material through the use of plain radiographs and computerized tomography (CT). METHODS: All patients received a Longevity HXLPE liner with tantalum beads and either a 28-mm or 36-mm femoral head. Twelve patients (6 in each head size group) agreed to return for 13-year RSA, plain radiograph, and CT follow-up. The 1-year and 13-year plain radiographs as well as the CT scans were analyzed for the presence of osteolysis. RESULTS: The 13-year mean ± standard error steady-state wear was 0.05 ± 0.02 mm with no significant increase over time or between the 2 head size groups. Two patients' CT scans showed radiolucent regions in the acetabulum of 4.51 cm(3) and 11.25 cm(3), respectively. In one patient, this area corresponded to a partially healed degenerative cyst treated with autograft during surgery. The second patient had an acetabular protrusio treated with autograft, and the CT scan revealed areas of remodeling of this graft. One patient's 13-year plain radiographs showed evidence of cup loosening and linear radiolucencies in zones 2 and 3. CONCLUSION: There was no evidence of significant wear over time using RSA. The CT scans did not show evidence of osteolysis due to wear particles. These results suggest that this material has reduced wear compared to conventional polyethylene, irrespective of head size.

What Is the Natural History of "Asymptomatic" Pseudotumours in Metal-on-Metal Hip Arthroplasty? Minimum 4-Year Metal Artifact Reduction Sequence Magnetic Resonance Imaging Longitudinal Study.

BACKGROUND: Metal Artifact Reduction Sequence Magnetic Resonance Imaging (MARS-MRI) is an important cross-sectional imaging modality in detection of metal-on-metal (MoM) hip arthroplasty (HA) pseudotumours. Potential evolution of pseudotumours detected by MARS-MRI in "asymptomatic" patients with MoMHA arthroplasty beyond 2 years remains largely unknown. The aims of this longitudinal study were to (1) determine the natural history of pseudotumours in "asymptomatic" MoMHA patients under MARS-MRI surveillance and (2) characterize MRI feature(s) associated with progressive pseudotumours. METHODS: A total of 37 MoMHA (32 patients, mean 56 years old) with pseudotumours on MARS-MRI were evaluated longitudinally using a standardized MARS-MRI protocol. Serum cobalt and chromium levels, pseudotumour size, thickness of the cyst wall, and MRI signal intensity of the abnormality were recorded and analyzed. RESULTS: At minimum of 4-year follow-up (range 49-54 months), 4 Type II pseudotumours (11%) demonstrated MRI evidence of progression. Five Type I pseudotumours (14%) were found to have "regressed." No measurable MRI progression was detected in remaining patients (75%). MRI features associated with progressive pseudotumours included the presence of increased cystic wall thickness and "atypical" mixed fluid signal. MRI pseudotumour progression was not associated with metal ion levels. CONCLUSION: The natural history of type I cystic pseudotumours continues to be nonprogressive in most "asymptomatic" MoMHA patients at minimum 4 years, suggesting the importance of patient symptoms and MRI characteristic features in the clinical decision-making process. Routine follow-up MARS-MRI evaluation of "asymptomatic" patients with low-grade cystic pseudotumours in the absence of interval clinical changes may not be indicated.

Three-Dimensional Imaging Analysis of Unicompartmental Knee Arthroplasty Evaluated in Standing Position: Component Alignment and In Vivo Articular Contact.

BACKGROUND: Component malalignment in unicompartmental knee arthroplasty (UKA) has been associated with contact stress concentration and poor clinical outcomes. However, there is a paucity of data regarding UKA component alignment and in vivo articular contact in weight-bearing position. This study aims to (1) quantify three-dimensional UKA component alignment and (2) evaluate the association between the component alignment and in vivo articular contact in standing position. METHODS: Seventy-seven UKAs in 68 consecutive patients were imaged in standing position using a biplanar X-ray imaging acquisition system. The UKA models were imported into a virtual imaging environment and registered with component silhouette on X-ray image for determination of component position and contact location. Anatomic bony landmarks of the lower limb were digitized for quantification of the bone alignment. RESULTS: The femoral component (FC) showed 1.6° ± 3.3° valgus, 6.5° ± 6.4° external rotation, and 2.4° ± 4.6° flexion. The tibial component (TC) showed 3.9° ± 4.5° varus, 4.4° ± 6.7° internal rotation, and 10.1° ± 4.6° tibial slope. The average contact point was located medially and posteriorly by 7.8 ± 7.6% and 0.7 ± 7.7% of TC dimensions to its center. Multiple regression analysis identified FC flexion as a significant variable affecting UKA anterior and/or posterior contact position (R = 0.549, P < .001). CONCLUSION: This study demonstrated the highest variability of UKA component positioning in axial plane rotation for FC and TC. The association between FC flexion and anterior contact position suggests accurate implant positioning may be important in optimizing in vivo UKA contact behavior. Further studies are required to gain understanding of the influence of axial rotation variability on in vivo UKA contact kinematics during functional activities.

Stable Fixation of a Cementless, Proximally Coated, Double Wedged, Double Tapered Femoral Stem in Total Hip Arthroplasty: A 5-Year Radiostereometric Analysis.

BACKGROUND: The objective of this 5-year prospective study of 51 hips was to assess migration of a cementless tapered femoral stem using radiostereometric analysis (RSA), plain radiographs (radiolucencies), and patient-reported outcome measures (PROMs). METHODS: Forty-seven patients (51 hips) agreed to participate in this prospective RSA study. All patients received a Taperloc stem. Tantalum beads were inserted into the femoral bone surrounding the stem to measure migration using RSA. RSA films, plain radiograph, and PROM follow-up were obtained immediately after surgery, 6 months, 1, 2, 3, and 5 years after surgery. RESULTS: The median (interquartile range) subsidence was 0.03 mm (-0.23 to 0.06) at 5 years, with no significant differences over time. Four outlier stems had >1.5 mm of subsidence by 1 year. No stem showed radiolucencies in more than 3 zones during the 5 years. All PROMs remained favorable at 5 years, suggesting an excellent outcome. There were no stems revised for mechanical loosening; 1 stem was revised for an infection. CONCLUSION: After initial settling, the cementless tapered femoral stems in our series were stable. The 4 outlier stems with >1.5 mm of subsidence by 1 year remain stable at 5 years. RSA was the most sensitive method of detection for stems at greater risk for potential future failure. This report adds contributions to the positive results associated with this type of fixation. The results at 5 years showed excellent midterm survivorship in this cohort with a cementless tapered femoral component.

Five-Year Experience of Vitamin E-Diffused Highly Cross-Linked Polyethylene Wear in Total Hip Arthroplasty Assessed by Radiostereometric Analysis.

BACKGROUND: Vitamin E-diffused highly cross-linked polyethylene (VEPE) was developed to reduce oxidation without compromising mechanical strength. The purpose of this study was to evaluate VEPE in vivo using radiostereometric analysis (RSA) and patient-reported outcome measures (PROMs). METHODS: Fifty-one hips were enrolled. Each patient received a VEPE liner, a porous titanium shell, and an uncemented stem with a 32-mm cobalt-chrome femoral head. Tantalum beads were inserted into the VEPE to measure femoral head penetration using RSA. RSA radiographs and PROMs were obtained preoperatively immediately after surgery, 6 months, 1, 2, 3, and 5 years after surgery. RESULTS: Forty-seven hips returned at 3 years, and 42 hip at 5 years. The mean ± standard error of the mean proximal head penetration into the polyethylene was 0.06 ± 0.01 at 5 years. The amount of head penetration did not change significantly with increasing time in vivo. The mean ± standard error of the mean Harris Hip Score was 58 ± 2 preoperatively, which improved significantly to 93 ± 2 at 5 years (P < .001). CONCLUSION: The head penetration into VEPE liners was low compared with non-VEPE at 5 years. After settling of the liners in the early period, no significant head penetration occurred from 2- to 5-year follow-up. All PROMs improved significantly from preoperative to postoperative and remained very favorable at 5 years. This study documents the longest-term evaluation of in vivo wear performance of VEPE.

The Use of Hyaluronic Acid and Corticosteroid Injections Among Medicare Patients With Knee Osteoarthritis.

INTRODUCTION: Hyaluronic acid (HA) and corticosteroid (CS) injections are frequently used in the management of osteoarthritis (OA) of the knee, despite a lack of strong evidence supporting their efficacy in the literature. The purpose of this study is to evaluate trends in HA and CS usage in Medicare patients over the past 15 years. METHODS: The Medicare 5% national sample database was used to identify 581,022 patients (representing an estimated 11.6 million) with a diagnosis of knee OA between 1999 and 2013. RESULTS: The percentage of newly diagnosed knee OA patients who received any injection trended from 39% in 1999 to 47% in 2006 and then declined to 37.5% in 2013. However, the mean number of injections per newly diagnosed OA patient nearly doubled from 0.27 to 0.45 for CS and from 0.18 to 0.36 for HA. Among those having both HA and CS injections, 69% had CS as first-line treatment, whereas 31% had HA first. CONCLUSION: The percentage of newly diagnosed knee OA patients receiving injections peaked in 2007 and then decreased steadily through 2013, as did the proportion of patients receiving HA injections as first-line therapy. However, the number of injections per patient has increased significantly over the past 15 years in both groups.

Surgeons' attitudes are associated with reoperation and readmission rates.

BACKGROUND: Attitudes influence how people make decisions. In an effort to decrease pilot judgment-related accidents, the Federal Aviation Administration teaches new pilots about hazardous attitudes that are believed to be incompatible with safe flight: macho, impulsive, worry, resignation, self-confidence, and antiauthority. If these attitudes are hazardous for pilots and their passengers, they may also be incompatible with the reliable and safe delivery of surgical care. QUESTIONS/PURPOSES: The purposes of this study were (1) to ascertain to what extent surgeons harbor hazardous attitudes; and (2) to determine their relationship, if any, to reoperation and readmission rates. METHODS: We selected validated aviation psychology tools that are used to measure these attitudes in pilots. We converted the aviation scenarios to analogous situations for surgeons and invited all surgeons from one academic program to participate in this study. A total of 41 surgeons were eligible to participate; 37 (90%) completed the attitude prevalence protocol and 31 (76%) had complete reoperation and readmission data for the correlation and regression analysis. Attending orthopaedic surgeons completed the Modified Surgeon Hazardous Attitude Scale as well as a series of additional instruments. RESULTS: Levels of macho thought to be hazardous in pilots were present in nine (24%) surgeons. Similar, elevated levels of self-confidence were found in three (8%) surgeons. High levels of impulsivity were found in 5% (two surgeons) and high levels of antiauthority were found in 3% (one surgeon). Only one (3%) surgeon reported elevated levels of worry and no surgeon reported hazardous levels of resignation. Thirty percent (11 surgeons) of surgeons harbored at least one elevated attitude level. In a regression model, macho attitude levels predicted 19% of the variation in surgeons' rate of readmissions and reoperations. CONCLUSIONS: High levels of hazardous attitudes may not be consistent with the routine delivery of safe surgical care in a teamwork setting where human factors and safe systems are the key to success. Further research is needed to determine if abnormally high levels of these hazardous attitudes impact patient care. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Do 360-degree feedback survey results relate to patient satisfaction measures?

BACKGROUND: There is evidence that feedback from 360-degree surveys-combined with coaching-can improve physician team performance and quality of patient care. The Physicians Universal Leadership-Teamwork Skills Education (PULSE) 360 is one such survey tool that is used to assess work colleagues' and coworkers' perceptions of a physician's leadership, teamwork, and clinical practice style. The Clinician & Group-Consumer Assessment of Healthcare Providers and System (CG-CAHPS), developed by the US Department of Health and Human Services to serve as the benchmark for quality health care, is a survey tool for patients to provide feedback that is based on their recent experiences with staff and clinicians and soon will be tied to Medicare-based compensation of participating physicians. Prior research has indicated that patients and coworkers often agree in their assessment of physicians' behavioral patterns. The goal of the current study was to determine whether 360-degree, also called multisource, feedback provided by coworkers could predict patient satisfaction/experience ratings. A significant relationship between these two forms of feedback could enable physicians to take a more proactive approach to reinforce their strengths and identify any improvement opportunities in their patient interactions by reviewing feedback from team members. An automated 360-degree software process may be a faster, simpler, and less resource-intensive approach than telephoning and interviewing patients for survey responses, and it potentially could facilitate a more rapid credentialing or quality improvement process leading to greater fiscal and professional development gains for physicians. QUESTIONS/PURPOSES: Our primary research question was to determine if PULSE 360 coworkers' ratings correlate with CG-CAHPS patients' ratings of overall satisfaction, recommendation of the physician, surgeon respect, and clarity of the surgeon's explanation. Our secondary research questions were to determine whether CG-CAHPS scores correlate with additional composite scores from the Quality PULSE 360 (eg, insight impact score, focus concerns score, leadership-teamwork index score, etc). METHODS: We retrospectively analyzed existing quality improvement data from CG-CAHPS patient surveys as well as from a department quality improvement initiative using 360-degree survey feedback questionnaires (Quality PULSE 360 with coworkers). Bivariate analyses were conducted to identify significant relationships for inclusion of research variables in multivariate linear analyses (eg, stepwise regression to determine the best fitting predictive model for CG-CAHPS ratings). In all higher order analyses, CG-CAHPS ratings were treated as the dependent variables, whereas PULSE 360 scores served as independent variables. This approach led to the identification of the most predictive linear model for each CG-CAHPS' performance rating (eg, [1] overall satisfaction; [2] recommendation of the physician; [3] surgeon respect; and [4] clarity of the surgeon's explanation) regressed on all PULSE scores with which there was a significant bivariate relationship. Backward stepwise regression was then used to remove unnecessary predictors from the linear model based on changes in the variance explained by the model with or without inclusion of the predictor. RESULTS: The Quality PULSE 360 insight impact score correlated with patient satisfaction (0.50, p = 0.01), patient recommendation (0.58, p = 0.002), patient rating of surgeon respect (0.74, p < 0.001), and patient impression of clarity of the physician explanation (0.69, p < 0.001). Additionally, leadership-teamwork index also correlated with patient rating of surgeon respect (0.46, p = 0.019) and patient impression of clarity of the surgeon's explanation (0.39, p = 0.05). Multivariate analyses supported retention of insight impact as a predictor of patient overall satisfaction, patient recommendation of the surgeon, and patient rating of surgeon respect. Both insight impact and leadership-teamwork index were retained as predictors of patient impression of explanation. Several other PULSE 360 variables were correlated with CG-CAHPS ratings, but none were retained in the linear models post stepwise regression. CONCLUSIONS: The relationship between Quality PULSE 360 feedback scores and measures of patient satisfaction reaffirm that feedback from work team members may provide helpful information into how patients may be perceiving their physicians' behavior and vice versa. Furthermore, the findings provide tentative support for the use of team-based feedback to improve the quality of relationships with both coworkers and patients. The 360-degree survey process may offer an effective tool for physicians to obtain feedback about behavior that could directly impact practice reimbursement and reputation or potentially be used for bonuses to incentivize better team professionalism and patient satisfaction, ie, "pay-for-professionalism." Further research is needed to expand on this line of inquiry, determine which interventions can improve 360-degree and patient satisfaction scores, and explain the shared variance in physician performance that is captured in the perceptions of patients and coworkers.

Does the Risk Assessment and Prediction Tool predict discharge disposition after joint replacement?

BACKGROUND: Payers of health services and policymakers place a major focus on cost containment in health care. Studies have shown that early planning of discharge is essential in reducing length of stay and achieving financial benefit; tools that can help predict discharge disposition would therefore be of use. The Risk Assessment and Prediction Tool (RAPT) is a preoperative survey constructed to predict discharge disposition after total joint arthroplasty (TJA). The RAPT was developed and tested on a population of Australian patients undergoing joint replacement, but its validity in other populations is unknown. A low RAPT score is reported to indicate a high risk of needing any form of inpatient rehabilitation after TJA, including short-term nursing facilities. QUESTIONS/PURPOSES: This study attempts (1) to assess predictive accuracy of the RAPT on US patients undergoing total hip and knee arthroplasty (THA/TKA); and (2) to determine predictive accuracy of each individual score (1-12). METHODS: Between June 2006 and December 2011, RAPT scores of 3213 patients (1449 THAs; 1764 TKAs) were prospectively captured during the preoperative clinical visit. Scores were stored along with other clinical data, including discharge disposition, in a dedicated database on a secure server. The database was queried by the nursing case manager to retrieve the RAPT scores of all patients captured during this time period. Binary logistic regression was used to analyze the scores and determine predictive accuracy. RESULTS: Overall predictive accuracy was 78%. RAPT scores<6 and >10 (of 12) predicted with >90% accuracy discharge to inpatient rehabilitation and home, respectively. Predictive accuracy was lowest for scores between 7 and 10 at 65.2% and almost 50% of patients received scores in this range. Based on our findings, the risk categories in our populations should be high risk<7, intermediate risk 7 to 10, and low risk>10. CONCLUSIONS: The RAPT accurately predicted discharge disposition for high- and low-risk patients in our cohort. Based on our data, intermediate-risk patients should be defined as those with scores of 7 to 10. Predictive accuracy for these patients could potentially be improved through the identification and addition of other factors correlated to discharge disposition. The RAPT allows for identification of patients who are likely to be discharged home or to rehabilitation, which may facilitate preoperative planning of postoperative care. Additionally, it identifies intermediate-risk patients and could be used to implement targeted interventions to facilitate discharge home in this group of patients. LEVEL OF EVIDENCE: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Comparative Epidemiology of Revision Arthroplasty: Failed THA Poses Greater Clinical and Economic Burdens Than Failed TKA.

BACKGROUND: Revision THA and TKA are growing and important clinical and economic challenges. Healthcare systems tend to combine revision joint replacement procedures into a single service line, and differences between revision THA and revision TKA remain incompletely characterized. These differences carry implications for guiding care and resource allocation. We therefore evaluated epidemiologic trends associated with revision THAs and TKAs. QUESTIONS/PURPOSES: We sought to determine differences in (1) the number of patients undergoing revision TKA and THA and respective demographic trends; (2) differences in the indications for and types of revision TKA and THA; (3) differences in patient severity of illness scoring between THA and TKA; and (4) differences in resource utilization (including cost and length of stay [LOS]) between revision THA and TKA. METHODS: The Nationwide Inpatient Sample (NIS) was used to evaluate 235,857 revision THAs and 301,718 revision TKAs between October 1, 2005 and December 31, 2010. Patient characteristics, procedure information, and resource utilization were compared across revision THAs and TKAs. A revision burden (ratio of number of revisions to total number of revision and primary surgeries) was calculated for hip and knee procedures. Severity of illness scoring and cost calculations were derived from the NIS. As our study was principally descriptive, statistical analyses generally were not performed; however, owing to the large sample size available to us through this NIS analysis, even small observed differences presented are likely to be highly statistically significant. RESULTS: Revision TKAs increased by 39% (revision burden, 9.1%-9.6%) and THAs increased by 23% (revision burden, 15.4%-14.6%). Revision THAs were performed more often in older patients compared with revision TKAs. Periprosthetic joint infection (25%) and mechanical loosening (19%) were the most common reasons for revision TKA compared with dislocation (22%) and mechanical loosening (20%) for revision THA. Full (all-component) revision was more common in revision THAs (43%) than in TKAs (37%). Patients who underwent revision THA generally were sicker (> 50% major severity of illness score) than patients who underwent revision TKA (65% moderate severity of illness score). Mean LOS was longer for revision THAs than for TKAs. Mean hospitalization costs were slightly higher for revision THA (USD 24,697 +/- USD 40,489 [SD]) than revision TKA (USD 23,130 +/- USD 36,643 [SD]). Periprosthetic joint infection and periprosthetic fracture were associated with the greatest LOS and costs for revision THAs and TKAs. CONCLUSIONS: These data could prove important for healthcare systems to appropriately allocate resources to hip and knee procedures: the revision burden for THA is 52% greater than for TKA, but revision TKAs are increasing at a faster rate. Likewise, the treating clinician should understand that while both revision THAs and TKAs bear significant clinical and economic costs, patients undergoing revision THA tend to be older, sicker, and have greater costs of care.

In vivo length change patterns of the medial and lateral collateral ligaments along the flexion path of the knee.

PURPOSE: The knowledge of the function of the collateral ligaments-i.e., superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL) and lateral collateral ligament (LCL)-in the entire range of knee flexion is important for soft tissue balance during total knee arthroplasty (TKA). The objective of this study was to investigate the length changes of different portions (anterior, middle and posterior) of the sMCL, dMCL and LCL during in vivo weightbearing flexion from full extension to maximal knee flexion. METHODS: Using a dual fluoroscopic imaging system, eight healthy knees were imaged while performing a lunge from full extension to maximal flexion. The length changes of each portion of the collateral ligaments were measured along the flexion path of the knee. RESULTS: All anterior portions of the collateral ligaments were shown to have increasing length with flexion except that of the sMCL, which showed a reduction in length at high flexion. The middle portions showed minimal change in lengths except that of the sMCL, which showed a consistent reduction in length with flexion. All posterior portions showed reduction in lengths with flexion. CONCLUSIONS: These data indicated that every portion of the ligaments may play important roles in knee stability at different knee flexion range. The soft tissue releasing during TKA may need to consider the function of the ligament portions along the entire flexion path including maximum flexion. LEVEL OF EVIDENCE: III.

A comprehensive analysis of Medicare trends in utilization and hospital economics for total knee and hip arthroplasty from 2005 to 2011.

The purpose of this study was to determine annual Medicare utilization and hospital reimbursement rates for total knee arthroplasty (TKA) and total hip arthroplasty (THA). A PearlDiver review of the entire Medicare database was conducted: 2,040,667 TKAs and 855, 899 THAs performed between 2005 and 2011 were identified. There was a +0.05% and +1.3% year over year growth in the utilization in hospital reimbursement for TKA and THA respectively. There has only been a modest increase in joint arthroplasty utilization for Medicare beneficiaries. Supply side issues, insurance mix and possible prior over-projection may explain this finding. Reimbursement trends suggest that joint arthroplasty may not be a major cost driver for the healthcare system.

What is the Fate of Total Hip Arthroplasty (THA) Acetabular Component Orientation When Evaluated in the Standing Position?

This retrospective study measured the change of the acetabular component orientation between supine and standing radiographs in 113 THA patients and identified the associated anatomical parameters that may help direct pre-operative planning. The mean change of the acetabular component inclination and version from supine to standing was 4.6° and 5.9° respectively (P<0.0001), with 49 (43%) hips showing inclination change >5° and 69 (53%) hips showing version change >5°. Twelve (43%) of 28 'malpositioned' cups became 'well-positioned' and 26 (31%) of 85 'well-positioned' cups became 'malpositioned' upon standing. Changes in inclination were associated with leg length discrepancy and pelvic obliquity; and changes in version were associated with pelvic tilt and pelvic incidence. Standing position and patient factors should be considered when defining "optimal" acetabular orientation.