EOS Imaging is Accurate and Reproducible for Preoperative Total Hip Arthroplasty Templating.

BACKGROUND: Templating is a critical part of preoperative planning for total hip arthroplasty (THA). The accuracy of templating on images acquired with EOS is unknown. This study sought to compare the accuracy and reproducibility of templating for THA using EOS imaging to conventional digital radiographs. METHODS: Forty-three consecutive primary unilateral THAs were retrospectively templated, six months postoperatively, using preoperative 2D EOS imaging and conventional radiographs. Two blinded observers templated each case for acetabular and femoral component size and femoral offset. The retrospectively templated sizes were compared to the sizes selected during surgery. Interobserver agreement was calculated, and the influence of demographic variables was explored. RESULTS: EOS templating predicted the exact acetabular and femoral size in 71% and 66% of cases, respectively, and to within one size in 98% of cases. The acetabular and femoral component size was more likely to be templated to the exact size using EOS compared to conventional imaging (P < .05). The femoral component offset choice was accurately predicted in 83% of EOS cases compared to 80% of conventional templates (P = .341). Component size and offset were not influenced by patient age, gender, laterality, or BMI. Interobserver agreement was excellent for acetabular (Cronbach's alpha = 0.94) and femoral (Cronbach's alpha = 0.96) component size. CONCLUSIONS: Preoperative templating for THA using EOS imaging is accurate, with an excellent interobserver agreement. EOS exposes patients to less radiation than traditional radiographs, and its three-dimensional applications should be explored as they may further enhance preoperative plans.

Digital Orthopaedics: A Glimpse Into the Future in the Midst of a Pandemic.

BACKGROUND: The response to COVID-19 catalyzed the adoption and integration of digital health tools into the health care delivery model for musculoskeletal patients. The change, suspension, or relaxation of Medicare and federal guidelines enabled the rapid implementation of these technologies. The expansion of payment models for virtual care facilitated its rapid adoption. The authors aim to provide several examples of digital health solutions utilized to manage orthopedic patients during the pandemic and discuss what features of these technologies are likely to continue to provide value to patients and clinicians following its resolution. CONCLUSION: The widespread adoption of new technologies enabling providers to care for patients remotely has the potential to permanently change the expectations of all stakeholders about the way care is provided in orthopedics. The new era of Digital Orthopaedics will see a gradual and nondisruptive integration of technologies that support the patient's journey through the successful management of their musculoskeletal disease.

Variation in Optimal Sagittal Alignment of the Femoral Component in Total Knee Arthroplasty.

Accurate sagittal alignment of the femoral component in total knee arthroplasty is crucial for prosthesis longevity, improved function, and patient satisfaction. However, there is variation in the techniques used to attain optimal sagittal femoral component placement in total knee arthroplasty. Femoral component flexion in imageless navigation is based on the mechanical axis rather than the distal femoral anatomy, and there is significant variability in the anatomy of the distal femur. The purpose of this study was to accurately determine the mean distal femoral flexion angle of a representative population and whether variability of the distal femoral flexion angle correlates with race, femur length, or radius of curvature. The mean degree of distal femoral flexion was determined by assessing distal femoral anatomy on computed tomography scans of paired femurs of 1235 patients without evidence of previous fracture, deformity, or surgical implants. The mean±SD distal femoral flexion angle was 2.90°±1.52°, with 80.2% of knees within 3°±2°. Therefore, placing the component in 3° of flexion from the mechanical axis would attain a satisfactory position in most cases. However, further analysis of the patient data revealed 11.4% of Asians, 7.3% of African Americans, and 8.3% of whites had a distal femoral flexion angle greater than 5°. Additionally, the data revealed a moderately strong negative correlation between the distal femoral flexion and the overall radius of curvature of the femur. This preliminary study highlights the need for improved methods for selecting femoral component position in the sagittal plane when using navigation for total knee arthroplasty. [Orthopedics. 2017; 40(2):102-106.].

No Difference in Dislocation Seen in Anterior Vs Posterior Approach Total Hip Arthroplasty.

BACKGROUND: The direct anterior approach (DAA) for total hip arthroplasty (THA) has rapidly become popular, but there is little consensus regarding the risks and benefits of this approach in comparison with a modern posterior approach (PA). METHODS: A total of 2147 patients who underwent DAA THA were propensity score matched with patients undergoing PA THA on the basis of age, gender, body mass index, and American Society of Anesthesia classification using data from a state joint replacement registry. Mean age of the matched cohort was 64.8 years, mean body mass index was 29.1 kg/m(2), and 53% were female. Multilevel logistic regression models using generalized estimating equations to control for grouping at the hospital level were used to identify differences in various outcomes. RESULTS: There was no difference in the dislocation rate between patients undergoing DAA (0.84%) and PA (0.79%) THA. Trends indicating a slightly longer length of stay with the PA and a slightly greater risk of fracture, increased blood loss, and hematoma with the DAA are consistent with previous studies. CONCLUSION: On the basis of short-term outcome and complication data, neither approach has a compelling advantage over each other, including no difference in the dislocation risk.

Development, implementation and evaluation of a patient handoff tool to improve safety in orthopaedic surgery.

OBJECTIVE: To develop, implement and test the effect of a handoff tool for orthopaedic trauma residents that reduces adverse events associated with the omission of critical information and the transfer of erroneous information. DESIGN: Components of this project included a literature review, resident surveys and observations, checklist development and refinement, implementation and evaluation of impact on adverse events through a chart review of a prospective cohort compared with a historical control group. SETTING: Large teaching hospital. PARTICIPANTS: Findings of a literature review were presented to orthopaedic residents, epidemiologists, orthopaedic surgeons and patient safety experts in face-to-face meetings, during which we developed and refined the contents of a resident handoff tool. The tool was tested in an orthopaedic trauma service and its impact on adverse events was evaluated through a chart review. The handoff tool was developed and refined during the face-to-face meetings and a pilot implementation. Adverse event data were collected on 127 patients (n = 67 baseline period; n = 60 test period). INTERVENTION: A handoff tool for use by orthopaedic residents. MAIN OUTCOME MEASUREMENTS: Adverse events in patients handed off by orthopaedic trauma residents. RESULTS: After controlling for age, gender and comorbidities, testing resulted in fewer events per person (25-27% reduction; P < 0.10). CONCLUSIONS: Preliminary evidence suggests that our resident handoff tool may contribute to a decrease in adverse events in orthopaedic patients.

Patients' perceptions of the costs of total hip and knee arthroplasty.

With medical economics in the national sociopolitical spotlight, we conducted a study to assess patients' understanding of the cost of 2 common orthopedic procedures: total hip and knee arthroplasty (THA, TKA). We surveyed 284 consecutive THA or TKA patients, at their first postoperative visit, regarding their understanding of reimbursement and cost. On average, patients estimated surgeon reimbursement at $12,014. They estimated that the hospital was reimbursed $28,392 for their perioperative care and that it cost the hospital $24,389 to provide it. The cost of the implant used was estimated at $6447. There is wide variation in patients' estimates and understanding of health care costs. However, patients substantially overestimate reimbursement to the surgeon both in isolation and as a proportion of the total cost of the surgical procedure.

A Computed Tomography Study of Gender Differences in Acetabular Version and Morphology: Implications for Femoroacetabular Impingement.

PURPOSE: To assess the prevalence of acetabular retroversion in a large population of patients with asymptomatic hips. Furthermore, we sought to identify gender differences in acetabular morphology to address the current thinking that retroversion and pincer-type femoroacetabular impingement (FAI) are more common in women. METHODS: We retrospectively reviewed morphologic features of acetabula from a consecutive series of trauma-protocol computed tomography scans of patients without pelvis injury. An automated algorithm determined the acetabular rim profile and center of the femoral head, normalized the frontal plane of the pelvis, and calculated version and coverage. We then compared male and female rim profiles, specifically focusing on version and acetabular wall coverage in the 1-o'clock (anterosuperior), 2-o'clock (central), and 3-o'clock (inferior) positions. RESULTS: Of 1,088 patients in the database, 878 had complete data (i.e., age, ethnicity, and body mass index) and were therefore included in the final analysis. Of these, 34.3% were women and 65.7% were men. Mean global acetabular version was 19.1° for men and 22.2° for women (P < .001). Mean acetabular version for men and women was 15.5° and 18.3°, respectively, in the 1-o'clock position; 21.5° and 24.0°, respectively, in the 2-o'clock position; and 20.2° and 24.3°, respectively, in the 3-o'clock position (P < .001 for all 3). True retroversion (<0°) was observed only in the 1-o'clock position. The prevalence of true acetabular retroversion in the 1-o'clock position for men and women was 4.3% and 3%, respectively (P = .36). CONCLUSIONS: Mean global and focal acetabular anteversion was greater in women, and the prevalence of focal cephalad retroversion in the 1-o'clock position was not significantly different compared with men. Acetabular retroversion and anterior overcoverage are not more prevalent in women in the anterosuperior acetabulum, where femoroacetabular impingement most commonly occurs. LEVEL OF EVIDENCE: Level III, diagnostic study.

Predictors of Satisfaction Following Total Knee Arthroplasty.

Despite the success of total knee arthroplasty (TKA), numerous studies report that nearly one in five patients who underwent TKA was unsatisfied with their outcome. The purpose of our study was to identify the preoperative factors predictive of satisfaction following well-performed TKA. Using improvement in patient-reported outcomes less than the minimally clinically important change as an indicator of dissatisfaction in a cohort of primary TKA patients, we found that patients with greater preoperative pain and disability with less severe degradation in health-related quality of life were more likely to be satisfied with the result of TKA. Balancing severity of symptoms and impact to quality of life is important when counseling patients considering TKA.

Pelvic tilt in patients undergoing total hip arthroplasty: when does it matter?

Pelvic tilt (PT) affects the functional anteversion and inclination of acetabular components in total hip arthroplasty (THA). One-hundred and thirty-eight consecutive patients who underwent unilateral primary THA were reviewed. Most cases had some degree of pre-operative PT, with 17% having greater than 10° of PT on standing pre-operative radiographs. There was no significant change in PT following THA. A computer model of a hemispheric acetabular component implanted in a range of anatomic positions in a pelvis with varying PT was created to determine the effects of PT on functional anteversion and inclination. Based on the study results, tilt-adjustment of the acetabular component position based on standing pre-operative imaging will likely improve functional component position in most patients undergoing THA.

Novel method for ensuring leg length in total hip arthroplasty.

Despite the overwhelming clinical success of total hip arthroplasty, complications such as leg-length discrepancy can be a significant cause of functional impairment and patient dissatisfaction. Multiple intraoperative techniques are available for measuring femoral limb length; however, many require additional invasive hardware and those that do not are less accurate at measuring limb length. This article introduces a novel, noninvasive intraoperative technique that quickly and accurately measures limb length and prevents postoperative leg-length discrepancy.The authors' method relies on the accurate reproduction of a line perpendicular to the femoral axis near the proximal aspect of the greater trochanter intraoperatively and during preoperative planning and requires minor modifications to the instrumentation used. A narrow slot for the placement of a guide plate was machined into a standard trial head 37° from the axis of the neck for use with a high offset 127° Secur-Fit PLUS stem and 42° from the axis of the neck for use with a standard offset 132° Secur-Fit stem (Stryker Orthopaedics, Kalamazoo, Michigan). Once a broach is securely seated, a trial neck, slotted trial head, and guide plate are assembled and the distance from the guide plate to the proximal tip of the greater trochanter is compared with the preoperative planning measurements to assess the stem position.A retrospective radiographic analysis of 31 consecutive primary total hip arthroplasty using this technique showed the mean postoperative leg-length discrepancy to be 2.18±6.08 mm. This method is an additional tool for the arthroplasty surgeon's armamentarium to ensure accurate leg-length restoration.

Cloud-based preoperative planning for total hip arthroplasty: a study of accuracy, efficiency, and compliance.

As digital radiography becomes more prevalent, several systems for digital preoperative planning have become available. The purpose of this study was to evaluate the accuracy and efficiency of an inexpensive, cloud-based digital templating system, which is comparable with acetate templating. However, cloud-based templating is substantially faster and more convenient than acetate templating or locally installed software. Although this is a practical solution for this particular medical application, regulatory changes are necessary before the tremendous advantages of cloud-based storage and computing can be realized in medical research and clinical practice.

Development and validation of a finite element model of the superior glenoid labrum.

Pathology of the superior glenoid labrum is a common source of musculoskeletal pain and disability. One of the proposed mechanisms of injury to the labrum is superior humeral head migration, which can be seen with rotator cuff insufficiency. Due to the size, anatomical location, and complex composition of the labrum, laboratory experiments have many methodological difficulties. The purpose of this study was to develop and validate a finite element model of the glenoid labrum. The model developed includes the glenoid labrum, glenoid cartilage, glenoid bone, and the humeral head cartilage. Labral displacements derived from the finite element model were compared to those measured during a controlled validation experiment simulating superior humeral head translations of 1, 2, and 3 mm. The results of the finite element model compared well to experimental measurements, falling within one standard deviation of the experimental data in most cases. The model predicted maximum average strains in the superior labrum of 7.9, 10.1, and 11.9%, for 1, 2, and 3 mm of humeral translation, respectively. The correspondence between the finite element model and the validation experiment supports the use of this model to better understand the pathomechanics of the superior labrum.

An integer programming model for distal humerus fracture fixation planning.

OBJECTIVE: To demonstrate the feasibility of an integer programming model to assist in pre-operative planning for open reduction and internal fixation of a distal humerus fracture. MATERIALS AND METHODS: We describe an integer programming model based on the objective of maximizing the reward for screws placed while satisfying the requirements for sound internal fixation. The model maximizes the number of bicortical screws placed while avoiding screw collision and favoring screws of greater length that cross multiple fracture planes. RESULTS: The model was tested on three types of total articular fractures of the distal humerus. Solutions were generated using 5, 9, 21 and 33 possible screw orientations per hole. Solutions generated using 33 possible screw orientations per hole and five screw lengths resulted in the most clinically relevant fixation plan and required the calculation of 1,191,975 pairs of screws that resulted in collision. At this level of complexity, the pre-processor took 104 seconds to generate the constraints for the solver, and a solution was generated in under one minute in all three cases. CONCLUSION: Despite the large size of this problem, it can be solved in a reasonable amount of time, making use of the model practical in pre-surgical planning.

Evaluation of three methods for determining EMG-muscle force parameter estimates for the shoulder muscles.

BACKGROUND: Accurate prediction of in vivo muscle forces is essential for relevant analyses of musculoskeletal biomechanics. The purpose of this study was to evaluate three methods for predicting muscle forces of the shoulder by comparing calculated muscle parameters, which relate electromyographic activity to muscle forces. METHODS: Thirteen subjects performed sub-maximal, isometric contractions consisting of six actions about the shoulder and two actions about the elbow. Electromyography from 12 shoulder muscles and internal shoulder moments were used to determine muscle parameters using traditional multiple linear regression, principal-components regression, and a sequential muscle parameter determination process using principal-components regression. Muscle parameters were evaluated based on their sign (positive or negative), standard deviations, and error between the measured and predicted internal shoulder moments. FINDINGS: It was found that no method was superior with respect to all evaluation criteria. The sequential principal-components regression method most frequently produced muscle parameters that could be used to estimate muscle forces, multiple regression best predicted the measured internal shoulder moments, and the results of principal-components regression fell between those of sequential principal-components regression and multiple regression. INTERPRETATION: The selection of a muscle parameter estimation method should be based on the importance of the evaluation criteria. Sequential principal-components regression should be used if a greater number of physiologically accurate muscle forces are desired, while multiple regression should be used for a more accurate prediction of measured internal shoulder moments. However, all methods produced muscle parameters which can be used to predict in vivo muscle forces of the shoulder.