Faculty Bibliography

PURPOSE: To evaluate the within-day and between-day measurement reproducibility of in vivo 3D MRI assessment of trabecular bone microarchitecture of the proximal femur. MATERIALS AND METHODS: This Health Insurance Portability and Accountability Act (HIPPA)-compliant, Institutional Review Board (IRB)-approved study was conducted on 11 healthy subjects (mean age = 57.4 +/- 14.1 years) with written informed consent. All subjects underwent a 3T MRI hip scan in vivo (0.234 x 0.234 x 1.5 mm) at three timepoints: baseline, second scan same day (intrascan), and third scan 1 week later (interscan). We applied digital topological analysis and volumetric topological analysis to compute the following microarchitectural parameters within the femoral neck: total bone volume, bone volume fraction, markers of trabecular number (skeleton density), connectivity (junctions), plate-like structure (surfaces), plate width, and trabecular thickness. Reproducibility was assessed using root-mean-square coefficient of variation (RMS-CV) and intraclass correlation coefficient (ICC). RESULTS: The within-day RMS-CVs ranged from 2.3% to 7.8%, and the between-day RMS-CVs ranged from 4.0% to 7.3% across all parameters. The within-day ICCs ranged from 0.931 to 0.989, and the between-day ICCs ranged from 0.934 to 0.971 across all parameters. CONCLUSION: These results demonstrate high reproducibility for trabecular bone microarchitecture measures derived from 3T MR images of the proximal femur. The measurement reproducibility is within a range suitable for clinical cross-sectional and longitudinal studies in osteoporosis. J. Magn. Reson. Imaging 2015;42:1339-1345.

OBJECTIVE: To determine the reliability of the Radiographic Union Scale for Tibia (RUST) score and a new modified RUST score in quantifying healing and to define a value for radiographic union in a large series of metadiaphyseal fractures treated with plates or intramedullary nails. DESIGN: Healing was evaluated using 2 methods: (1) evaluation of interrater agreement in a series of radiographs and (2) analysis of prospectively gathered data from 2 previous large multicenter trials to define thresholds for radiographic union. INTERVENTION: Part 1: 12 orthopedic trauma surgeons evaluated a series of radiographs of 27 distal femur fractures treated with either plate or retrograde nail fixation at various stages of healing in random order using a modified RUST score. For each radiographic set, the reviewer indicated if the fracture was radiographically healed. Part 2: The radiographic results of 2 multicenter randomized trials comparing plate versus nail fixation of 81 distal femur and 46 proximal tibia fractures were reviewed. Orthopaedic surgeons at 24 trauma centers scored radiographs at 3, 6, and 12 months postoperatively using the modified RUST score above. Additionally, investigators indicated if the fracture was healed or not healed. MAIN OUTCOME MEASURES: The intraclass correlation coefficient (ICC) with 95% confidence intervals was determined for each cortex, the standard and modified RUST score, and the assignment of union for part 1 data. The RUST and modified RUST that defined "union" were determined for both parts of the study. RESULTS: ICC: The modified RUST score demonstrated slightly higher ICCs than the standard RUST (0.68 vs. 0.63). Nails had substantial agreement, whereas plates had moderate agreement using both modified and standard RUST (0.74 and 0.67 vs. 0.59 and 0.53). UNION: The average standard and modified RUST at union among all fractures was 8.5 and 11.4. Nails had higher standard and modified RUST scores than plates at union. The ICC for union was 0.53 (nails: 0.58; plates: 0.51), which indicates moderate agreement. However, the majority of reviewers assigned union for a standard RUST of 9 and a modified RUST of 11, and >90% considered a score of 10 on the RUST and 13 on the modified RUST united. CONCLUSIONS: The ICC for the modified RUST is slightly higher than the standard RUST in metadiaphyseal fractures and had substantial agreement. The ICC for the assessment of union was moderate agreement; however, definite union would be 10 and 13 with over 90% of reviewers assigning union. These are the first data-driven estimates of radiographic union for these scores.

OBJECTIVE:: To evaluate the ability of surgeons to determine if the fibula is reduced in the sagittal plane in relation to the tibia based upon fluoroscopic images by comparison with the known normal for both the ipsilateral and contralateral ankles. METHODS:: Perfect lateral radiographs of both ankles were obtained in seven cadaveric specimens. The fibula was translated 2.5mm and 5mm in the anterior and posterior directions. Four orthopedic trauma-trained surgeons were presented with a fictitious case consisting of a "normal" image, followed by 10 randomly selected images from both ankles, and were asked to determine if the fibula was reduced, or displaced anteriorly or posteriorly. The ability of the surgeons to identify displacement and inter-observer reliability were assessed. RESULTS:: The surgeons were better able to identify malreduction than reduction (NPV 95% ipsilateral, 85% contralateral). The overall sensitivity for reduction was 94% for the ipsilateral ankle, but only 68% for the contralateral ankle. Anterior displacement and greater magnitudes of displacement were most easily diagnosed. All reviewers had the most difficulty with 2.5mm of posterior displacement. The intraobserver agreement was excellent for anterior displacement and 5mm of displacement in either direction (kappa .71/.75). Surgeons who routinely used the contralateral lateral radiograph were more accurate. CONCLUSIONS:: While it is unknown how much translational displacement of the syndesmosis is acceptable, it seems that the experienced surgeon will be able to reduce the joint within 2.5mm and that fluoroscopic comparisons to the normal ankle are helpful in determining malreduction.

OBJECTIVE: To evaluate the effect of syndesmotic disruption on the functional outcomes of Weber B, SE4 ankle fractures treated operatively. SETTING: Multicenter trauma hospitals. PATIENTS: Data were prospectively gathered during a previous, multicenter randomized trial including 242 patients (136 women, 106 men) from 9 trauma centers with operatively treated Weber B SE4 ankle fractures. There were 81 patients (35%) with syndesmotic instability confirmed intraoperatively after fibula fixation. INTERVENTION: Functional evaluations were performed postoperatively at 6, 12, 26, and 52 weeks. The presence of symptomatic hardware and peroneal tendon discomfort was evaluated with 9-12 months of follow-up. MAIN OUTCOME MEASURES: Functional outcomes evaluated included Short Musculoskeletal Function Assessment (SMFA), Bother index, and American Orthopaedic Foot and Ankle Society (AOFAS) scores. The recovery curve of the 2 groups was analyzed using a mixed linear regression analysis for repeated measures and included gender and race in the model. Symptomatic hardware and peroneal tendon discomfort were compared between the 2 groups with a chi analysis. RESULTS: The adjusted mean linear regression analyses demonstrated that patients without a syndesmotic injury had better functional outcomes for some outcome measures. SMFA scores at 12 weeks were statistically lower in patients without syndesmotic injury (P = 0.02), but not at other visits. AOFAS scores were significantly higher (P = 0.0006), and Bother index trended toward lower results (P = 0.07) in patients without syndesmotic injury at all time points. Isolated analyses (T-tests) at 1 year demonstrated a difference in the SMFA (P = 0.04) and Bother index (P = 0.05), but not the AOFAS (P = 0.21). Men consistently demonstrated better recovery than women for all outcomes, whereas race was not significant for any measure. Symptomatic hardware and peroneal tendon irritation was not statistically different between the groups. CONCLUSIONS: The recovery curves after ankle fractures were different based on syndesmotic injury. However, the difference was at the limit of clinical significance. Syndesmotic injury has a slightly detrimental effect on outcomes of operatively treated Weber B SE4 fractures. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

INTRODUCTION: The purpose of this study was to determine if nutritional screening could be used as a predictor for the development of complications and hospital readmissions. METHODS: A variation of the Malnutrition Universal Screening Tool (MUST) score was collected for all inpatients with orthopaedic trauma on admission to our hospital from 2009 to 2011. We retrospectively compared each patient's MUST score with the subsequent development of infection, venous thromboembolism, respiratory failure, ulceration, or readmission. Finally, a chart review was performed to collect comorbidity data and evaluate Charlson comorbidity indexes to estimate the overall health of each patient with an available MUST. RESULTS: Of the 796 consecutive patients in our total cohort, 57.7% (n = 459) were of normal nutritional status and 42.3% (n = 337) exhibited at least 1 sign of malnutrition. In patients with normal nutrition, 2.8% developed at least one of the specified complications, and we observed a complication-to-patient ratio of 0.033. In patients with signs of malnutrition, 8.0% developed at least 1 complication with a complication-to-patient ratio of 0.101. This difference was significant (P = 0.001). Multivariate regression analysis demonstrated that each additional point in a patient's nutrition score corresponded to a 49.5% increase in the odds of developing a complication when controlling for other factors (odds ratio = 1.495, confidence interval = 1.120-1.997, P = 0.006). Charlson comorbidity indexes were not significantly associated with total complications when MUST scores used were a covariant. DISCUSSION AND CONCLUSIONS: Patients treated for fractures and dislocations with any sign of malnutrition according to the MUST score were more than twice as likely to acquire some combination of infection, venous thromboembolism, respiratory failure, or other reason for readmission than those of normal nutritional status. Increasing levels of malnourishment corresponded with increasing risk for developing complications, whereas these complications were not necessarily associated with higher comorbidity. An assessment of a fracture patient's nutritional status should be considered a factor in evaluating risks related to fracture care. The MUST score is a predictive tool. These data have important implications for hospitals whose fiscal reimbursement is dependent on the maintenance of defined quality measures. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

INTRODUCTION: Osteoporosis is a disease of weak bone. Our goal was to determine the measurement reproducibility of magnetic resonance assessment of proximal femur strength. METHODS: This study had institutional review board approval, and written informed consent was obtained from all subjects. We obtained images of proximal femur microarchitecture by scanning 12 subjects three times within 1 week at 3T using a high-resolution 3-D FLASH sequence. We applied finite element analysis to compute proximal femur stiffness and femoral neck elastic modulus. RESULTS: Within-day and between-day root-mean-square coefficients of variation and intraclass correlation coefficients ranged from 3.5 to 6.6 % and 0.96 to 0.98, respectively. CONCLUSION: The measurement reproducibility of magnetic resonance assessment of proximal femur strength is suitable for clinical studies of disease progression or treatment response related to osteoporosis bone-strengthening interventions.

OBJECTIVES:: To empirically define a "delay" for hip fracture surgery based on clinical outcomes, and to identify patient demographics and hospital factors contributing to surgical delay. DESIGN:: Retrospective database analysis. SETTING:: Hospital discharge data. PATIENTS/PARTICIPANTS:: A total of 2,121,215 patients undergoing surgical repair of hip fracture in the National Inpatient Sample (NIS) between 2000 and 2009. INTERVENTION:: Internal fixation or partial/total hip replacement. MAIN OUTCOME MEASUREMENTS:: Logistic regressions were performed to assess the effect of surgical timing on in-hospital complication and mortality rates, controlling for patient characteristics and hospital attributes. Subsequent regressions were performed to analyze which patient characteristics (age, gender, race, comorbidity burden, insurance status, and day of admission) and hospital factors (size, teaching status, and region) independently contributed to the likelihood of surgical delay. RESULTS:: Compared to same-day surgery, each additional day of delay was associated with a significantly higher overall complication rate. However, next-day surgery was not associated with an increased risk of in-hospital mortality. Surgery 2 calendar days (OR: 1.13) and 3+ days (OR: 1.33) following admission was associated with higher mortality rates. Based on these findings, "delay" was defined as surgery performed two or more days after admission. Significant factors related to surgical delay included comorbidity score, race, insurance status, hospital region, and day of admission. CONCLUSIONS:: Surgical delay in hip fracture care contributes to patient morbidity and mortality. A variety of patient and hospital characteristics seem to contribute to surgical delay, and point to important health care disparities. LEVEL OF EVIDENCE:: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVES:: To quantify the impact of compartment syndrome in the setting of tibial shaft fracture on hospital length of stay and total hospital charges. DESIGN:: Retrospective case-control study. SETTING:: All New York State hospital admissions from 2001-2011, as recorded by the New York Statewide Planning and Research Cooperative System (SPARCS) database. PATIENTS:: 33,629 inpatients with isolated open or closed fractures of the tibia and/or fibula (AO/OTA 41-43). 692 patients developed a compartment syndrome in the setting of tibia fracture. All patients were filtered to ensure none had other complications or medical comorbidities that would increase length of stay or total hospital charges. INTERVENTION:: Fasciotomy and delayed closure in patients who developed a compartment syndrome. MAIN OUTCOME MEASURE:: Hospital length of stay (days) and total inflation-adjusted hospital charges RESULTS:: A total of 33,629 patients with tibial shaft fracture were included in the study. There were 32,937 patients who did not develop a compartment syndrome. For this group, the mean length of stay was 6 days and the mean inflation-adjusted hospital charges were $34,000. Patients who developed compartment syndrome remained in-house for an average of 14 days with average charges totaling $79,000. These differences were highly significant for both lengths of stay and hospital charges (p < 0.001). CONCLUSION:: Besides the obvious physical detriment experienced by patients with compartment syndrome, there is also a significant economic impact to the healthcare system. Compartment syndrome following a tibial fracture more than doubles length of stay and total hospital charges. These findings highlight the need for a standardized care algorithm aimed towards efficiently and adequately treating acute compartment syndrome. Such an algorithm would optimize cost of care and presumably decrease length of stay. LEVEL OF EVIDENCE:: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

OBJECTIVES: While the posteromedial fragment in tibial plateau fractures is often considered unstable, biomechanical evidence supporting this view is lacking. We aimed to evaluate the stability of the fragment in a cadaver model. Our hypothesis was that under the expected small axial force during rehabilitation and the combined effects of this force with shear force, internal rotation torque and varus moment, the most common posteromedial tibia fragment morphology could maintain stability in early flexion. METHODS: Axial compression force alone or combined with either posterior shear, internal rotation torque, or varus moment was applied to the femurs of five fresh cadaveric knees. A Tekscan pressure mapping system was used to measure pressure and contact area between the femoral condyles, meniscus, and tibial plateau. A Microscribe 3D digitizer was used to define the three-dimensional positions of the femur and tibia. A 10 mm and then a 20 mm osteotomy was created with a saw at an angle of 30 degrees in the axial plane with respect to the tangent of the posterior tibial plateau and 75 degrees in the sagittal plane, representing a typical posteromedial fracture fragment. At each flexion angle (15 degrees , 30 degrees , 60 degrees , 90 degrees , 120 degrees ) and loading condition (axial compression only, compression with shear force, torque, and varus moment), distal displacement of the medial femoral condyle as well as the tibial fracture fragments, were determined. RESULTS: For the 10 mm fragment, medial femoral condyle displacement was little affected up to approximately 30 degrees flexion, after which it increased. For the 20 mm fragment, there was progressive medial femoral condyle displacement with increasing flexion from baseline. However, for the 10mm and 20mm fragments themselves, displacements were noted at every flexion angle, starting at 1.7mm inferior displacement with 15 degrees of flexion and internal rotation torque and up to 10.2mm displacement with 90 degrees flexion and varus bending moment. CONCLUSIONS: In this cadaveric model of a posteromedial tibial plateau fracture, both fracture fragments studied displaced with knee flexion, even at low flexion angles. While such fragments may initially appear non-displaced after injury, posteromedial fragments similar to these tested are likely to displace during knee range of motion exercises in non-weight bearing conditions.

Tibial plateau fractures present in a wide spectrum of injury severity and pattern, each requiring a different approach and strategy to achieve good clinical outcomes. Achieving those outcomes starts with a thorough evaluation and preoperative planning period, which leads to choosing the most appropriate surgical approach and fixation strategy. Through a case-based approach, this article presents the necessary pearls, techniques, and strategies to maximize outcomes and minimize complications for some of the more commonly presenting plateau fracture patterns.