Joseph D. Maratt

Variation in the femoral bow: a novel high-throughput analysis of 3922 femurs on cross-sectional imaging.

Objectives: To evaluate femoral radius of curvature in a large sample of computed tomography scans to definitively determine the relationship between radius of curvature and femoral length, age, gender, ethnicity, body mass index and cortical thickness. Methods: A retrospective review was conducted of the electronic medical records and advanced imaging of 1961 patients who underwent pulmonary embolism protocol computed tomography scans between December 1999 and March 2010. The computed tomography scans were imported from the clinical picture archiving and communication system archive into a research image archive and analysis system. Each scan was processed by an automated system that algorithmically determined bony landmarks, adjusted for body position within the scanner and measured the radius of curvature. Results: The mean medullary radius of curvature of 3922 femurs was 112 cm (SD = 26 cm). The mean anterior radius of curvature of the femurs was 145 cm (SD = 55 cm). There was a moderately strong positive correlation (0.36–0.39) between femoral length and radius of curvature (P < 0.0001) that was not affected by age, body mass index, cortical thickness, gender, or ethnicity. No significant relationship was found between either gender or ethnicity and radius of curvature independent of femoral length. Conclusions: Differences in radius of curvature based on ethnicity and gender exist primarily because of the variation in average height, and therefore femur length, that exists between ethnic groups and genders. These data may prove useful in the design of safer intramedullary implants that accommodate a greater spectrum of anatomic variation.

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.

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.

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.

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.].

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.