Excessive standing posterior pelvic tilt (PT), lumbar spine stiffness, low pelvic Incidence (PI), and severe sagittal spinal deformity (SSD) have been linked to increased dislocation rates. We aimed to compare the prevalence of these 4 parameters in unstable and stable primary Total Hip Arthroplasty (THA) patients. In this retrospective cohort study, 40 patients with instability following primary THA for osteoarthritis were referred for functional analysis. All patients received lateral X-rays in standing and flexed seated positions to assess functional pelvic tilt and lumbar lordosis (LL). Computed tomography scans were used to measure pelvic incidence and acetabular cup orientation. Literature thresholds for “at risk” spinopelvic parameters were standing pelvic tilt ≤ −10°, lumbar flexion (LLstand – LLseated) ≤ 20°, PI ≤ 41°, and sagittal spinal deformity (PI – LLstand mismatch) ≥ 10°. The prevalence of each risk factor in the dislocation cohort was calculated and compared to a previously published cohort of 4042 stable THA patients.Introduction
Methods
The purpose of this study is to evaluate the early outcomes with the use of a smartphone-based exercise and educational platform after primary total hip arthroplasty compared to a standard of care control group. A multicenter prospective randomized control trial was conducted evaluating the use of the mymobility smartphone-based care platform for primary total hip arthroplasty (THA). Patients randomized to the control group (198 patients) received the respective institution's standard of care. Those randomized to mymobility treatment group (167 patients) were provided an Apple Watch and mymobility smartphone application. The application provides pre and postoperative educational content, video directed exercise programs as well as tracks the patient's activity. Patients in the treatment group were not initially prescribed physical therapy, but could be if their surgeon deemed it necessary. Early outcomes assessed included 90-day hip range of motion, HOOS JR scores, 30-day single leg stance (SLS) and time up and go (TUG) test. We also evaluated PT utilization, THA complications associated with readmissions, ER visits not associated with readmissions, urgent care (non standard of care) visits, and physician office visits. Outcome scores include HOOS-Jr, EQ-5D-5L, single stance (SLS), Timed up and go (TUG). Satisfaction scores for the procedure and the mymobility study group were also recorded.Background
Methods
Computer-assisted orthopaedic surgery (CAOS) improves mechanical alignment and the accuracy of surgical cuts in the context of total knee arthroplasty. A simplified, CAOS enhanced instrumentation system was assessed to determine if the same effects could be achieved through the use of a less intrusive system. Two cohorts of surgeons (experienced and trainees) performed a series of total knee arthroplasty resections in knee models with and without navigation-enhanced instrumentation. The percentage of resections that deviated from the planned cut by more than 2°or 2mm (outliers) was determined by post-resection advanced imaging for six unique outcome metrics. Within each experience level, the use of the CAOS enhanced system significantly reduced the total percentage of outliers as compared to conventional instrumentation (Figure 1). The experienced users improved from 35% to 4% outliers overall (p < .001) and the trainees from 34% to 10% outliers (p < .001). Comparing across experience levels, the experienced surgeons performed significantly better in only a single resection metric with conventional instrumentation (Figure 2A), varus/valgus tibial alignment, with 8.3% outliers compared to the trainee's 63% outliers (p = .004). The use of CAOS enhanced instrumentation eliminated any differences between the two user groups for all measured resections (Figure 2B). Comparing CAOS enhanced to conventional instrumentation specifically between anatomical deformity types revealed that there is significant improvement (p < .05) with the use of enhanced instrumentation for all three deformity types (Figure 3). These results suggest that non-intrusive CAOS enhanced instrumentation is a viable alternative to conventional instrumentation with possible benefits. This trial also demonstrates that additional experience may not correlate to improved surgical accuracy, and outliers may be less a result of individual surgeon ability or specific anatomic deformities, and more so related to limitations of the instrumentation used or other yet unidentified factors.
The aim of this study was to evaluate the effects of posterior tibial slope (PTS) and posterior condylar offset (PCO) on patient-reported pain and function one year after TKA. A total of 500 patients from 11 clinics in 6 countries were enrolled into a prospective, multicenter study. All patients were indicated for primary TKA for OA and received components from a single manufacturer. All liners were made from vitamin-E stabilized, highly crosslinked (95 kGy) polyethylene; 54.7% were posterior stabilized (PS) and the remaining were cruciate-retaining. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was administered at the one-year follow-up visit. The KOOS pain and activities in daily life (ADL) sub-scores were dichotomized and served as the primary outcomes. Dichotomization was done with the patient acceptable symptom state (PASS), defined by previous studies as the value of the PROM above which patients deem their state as acceptable (84.5 points for KOOS pain and 83.0 points for KOOS ADL). Plain lateral radiographs were taken and assessed for PTS (Figure 1) and PCO (Figure 2). PTS was categorized as above (excessive flexion), within (ideal), or below (extension) the safe zone of 0° − 7° of flexion. PCO increases or decreases of greater than 3mm were compared against no change (≤ 3mm). Each of the two sagittal positioning metrics was tested against the KOOS pain and ADL PASS at one year.Introduction
Methods
Bundle payment models have clinical and economic impacts on providers. Despite efforts made to improve care, experience has shown that a few episodes with costs well above a target (bundle busters) can reduce or negate positive performances. The purpose of this study was to identify both the primary episode drivers of cost and patient factors that led to episodes above target. A retrospective study of 10,000 joint replacement episodes from a large healthcare system in CJR and a private orthopedic practice in BPCI was conducted. Episodes with costs greater than target price (TP) were designated as bundle busters and sub-divided into 4 groups:
< 1 standard deviation (SD) above TP (n=1700) > 1 to 2 SD above TP (n=240) > 2 to 3 SD above TP (n=70) > 3 SD above TP (n=70) Bundle busters were compared to the control that were at/below the TP (n= 7500). For the CJR/BPCI cohorts, one SD was defined as $10,700/$13,000, respectively. Two linear regressions assessed the likelihood of factors predicting a bundle buster and the total episode cost. These variables included demographics, acuity classifications, comorbidities, length of stay, readmissions, discharge disposition, post-acute utilization, and episode costs.Introduction
Methods
Despite that computer-assisted orthopaedic surgery (CAOS) has been shown to offer increased accuracy to the bony resections compared to the conventional techniques [1], previous studies of CAOS have mostly focused on alignment outcomes based on a small number of patients [1]. Although several recent meta-analyses on the CAOS outcomes have been reported [2], these analyses did not differentiate between systems, while system-dependency has been reported to influence alignment parameters [3]. To date, no study has benchmarked a specific CAOS system based on a large number of clinical cases. The purpose of this study is to assess the accuracy and precision of bony resection in more than 4000 cases using a specific contemporary CAOS system. Technical logs of 4292 TKAs performed between October 2012 and January 2016 using a contemporary CAOS system (ExactechGPS, Blue-Ortho, Grenoble, FR) were analyzed. The analyses were performed on: 1) planned resection, defined by the surgeon prior to the bone cuts. These parameters serve as inputs for the CAOS guidance; and 2) Checked resection, defined as digitalization of the actual resection surfaces by manually pressing an instrumented checker onto the bony cuts. Deviations in alignment and resection depths (on the referenced side) between planned and checked resections were calculated in coronal and sagittal planes for both tibia and femur (planned vs checked).INTRODUCTION
Materials and Methods
Although several meta-analyses have been performed on total knee arthroplasty (TKA) using computer-assisted orthopaedic surgery (CAOS) [1], understanding the inter-site variations of the surgical profiles may improve the interpretation of the results. Moreover, information on the global variations of how TKA is performed may benefit the development of CAOS systems that can better address geographic-specific operative needs. With increased application of CAOS [2], surgeon preferences collected globally offers unprecedented opportunity to advance geographic-specific knowledge in TKA. The purpose of this study was to investigate geographic variations in the application of a contemporary CAOS system in TKA. Technical records on more than 4000 CAOS TKAs (ExactechGPS, Blue-Ortho, Grenoble, FR) between October 2012 and January 2016 were retrospectively reviewed. A total of 682 personalized surgical profiles, set up based on surgeon's preferences, were reviewed. These profiles encompass an extensive set of surgical parameters including the number of steps to be navigated, the sequence of the surgical steps, the definition of the anatomical references, and the parameters associated with the targeted cuts. The profiles were compared between four geographic regions: United States (US), Europe (EU), Asia (AS), and Australia (AU) for cruciate-retaining (CR) and posterior-stabilized (PS) designs. Clinically relevant statistical differences (CRSD, defined as significant differences in means ≥1°/mm) were identified (significance defined as p<0.05).INTRODUCTION
Materials and Methods
Alternative payment models, such as bundled payments, aim to control rising costs for total knee (TKA) and total hip arthroplasty (THA). Without risk adjustment for patients who may utilize more resources, concerns exist about patient selection and access to care. The purpose of this study was to determine whether lower socioeconomic status (SES) was associated with increased resource utilization following TKA and THA. Using the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database, we reviewed a consecutive series of 4,168 primary TKA and THA patients over a 3-year period. We defined lowest SES based upon the median household income of the patient's ZIP code. An Introduction
Methods
Studies have reported that only 70–80% of the total knee arthroplasty (TKA) cases using conventional instruments can achieve satisfactory alignment (within ±3° of the mechanical axis). Computer-assisted orthopaedic surgery (CAOS) has been shown to offer increased accuracy and precision to the bony resections compared to conventional techniques [1]. As the early adopters champion the technology, reservation may exist among new CAOS users regarding the ability of achieving the same results. The purpose of this study was to investigate if there are immediate benefits in the accuracy and precision of achieving surgical goals for the novice surgeons, as compared to the experienced surgeons, by using a contemporary CAOS system. Two groups of surgeons were randomly selected from TKAs between October 2012 and January 2016 using a CAOS system (ExactechGPS, Blue-Ortho, Grenoble, FR), including:
All the surgeries from the INTRODUCTION
Materials and Methods
Proper cup positioning is a critical component in the success of total hip arthroplasty surgery. A multicenter study has been initiated to study a new type of highly cross-linked polyethylene. This study provides a unique opportunity to a review the acetabular cup placement of over 500 patients implanted in the past 2 years from 13 medical centers from the U.S., Mexico, and Europe. 482 patients have received primary total hip arthroplasty using components from a single manufacturer in 5 centers in the US and Mexico and 7 centers in Europe. The acetabular anteversion and inclination were measured in post-operative radiographs. An acceptable window of cup position is defined at 5–25° of anteversion and 30–45° of inclination.Introduction
Methods
