Dual Plate Fixation of Periprosthetic Distal Femur Fractures.

OBJECTIVES: Dual implants for distal femur periprosthetic fractures is a growing area of interest for these challenging fractures with dual plating (DP) emerging as a viable construct for these injuries. In the current study, an experience with DP constructs is described. DESIGN: Retrospective case series with comparison group. SETTING: Level 1 academic trauma center. PATIENT SELECTION CRITERIA: Adults >50 years old sustaining comminuted OTA/AO 33-A2 or 33-A3 DFPF treated with either DP or a single distal femur locking plating (DFLP). Patients with simple 33-A1 fractures were excluded. Prior to 2018, patients underwent DFLP after which the treatment of choice became DP. OUTCOME MEASURES AND COMPARISONS: Reoperation rate, alignment, and complications. RESULTS: 34 patients treated with DFLP and 38 with DP met inclusion and follow up criteria. Average follow up was 18.2 ± 13.8 months in the DFLP group and 19.8 ± 16.1 months in the DP group ( P = 0.339). The average patient age in the DFLP group was 74.8 ± 7.3 years compared to 75.9 ± 11.3 years in the DP group. There were no statistical differences in demographics, fracture morphology, loss of reduction, or reoperation for any cause ( P >.05). DP patients were more likely to be weight bearing in the twelve-week postoperative period ( P <0.001) and return to their baseline ambulatory status ( P = 0.004) compared to DFLP patients. CONCLUSIONS: Dual plating of distal femoral periprosthetic fractures maintained coronal alignment with a low reoperation rate even with immediate weight bearing and these patients regained baseline level of ambulation more reliably as compared to patients treated with a single distal femoral locking plate. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Modification to Mirels scoring system location component improves fracture prediction for metastatic disease of the proximal femur.

BACKGROUND: Correctly identifying patients at risk of femoral fracture due to metastatic bone disease remains a clinical challenge. Mirels criteria remains the most widely referenced method with the advantage of being easily calculated but it suffers from poor specificity. The purpose of this study was to develop and evaluate a modified Mirels scoring system through scoring modification of the original Mirels location component within the proximal femur. METHODS: Computational (finite element) experiments were performed to quantify strength reduction in the proximal femur caused by simulated lytic lesions at defined locations. Virtual spherical defects representing lytic lesions were placed at 32 defined locations based on axial (4 axial positions: neck, intertrochanteric, subtrochanteric or diaphyseal) and circumferential (8 circumferential: 45-degree intervals) positions. Finite element meshes were created, material property assignment was based on CT mineral density, and femoral head/greater trochanter loading consistent with stair ascent was applied. The strength of each femur with a simulated lesion divided by the strength of the intact femur was used to calculate the Location-Based Strength Fraction (LBSF). A modified Mirels location score was next defined for each of the 32 lesion locations with an assignment of 1 (LBSF > 75%), 2 (LBSF: 51-75%), and 3 (LBSF: 0-50%). To test the new scoring system, data from 48 patients with metastatic disease to the femur, previously enrolled in a Musculoskeletal Tumor Society (MSTS) cross-sectional study was used. The lesion location was identified for each case based on axial and circumferential location from the CT images and assigned an original (2 or 3) and modified (1,2, or 3) Mirels location score. The total score for each was then calculated. Eight patients had a fracture of the femur and 40 did not over a 4-month follow-up period. Logistic regression and decision curve analysis were used to explore relationships between clinical outcome (Fracture/No Fracture) and the two Mirels scoring methods. RESULTS: The location-based strength fraction (LBSF) was lowest for lesions in the subtrochanteric and diaphyseal regions on the lateral side of the femur; lesions in these regions would be at greatest risk of fracture. Neck lesions located at the anterior and antero-medial positions were at the lowest risk of fracture. When grouped, neck lesions had the highest LBSF (83%), followed by intertrochanteric (72%), with subtrochanteric (50%) and diaphyseal lesions (49%) having the lowest LBSF. There was a significant difference (p < 0.0001) in LBSF between each axial location, except subtrochanteric and diaphyseal which were not different from each other (p = 0.96). The area under the receiver operator characteristic (ROC) curve using logistic regression was greatest for modified Mirels Score using site specific location of the lesion (Modified Mirels-ss, AUC = 0.950), followed by a modified Mirels Score using axial location of lesion (Modified Mirels-ax, AUC = 0.941). Both were an improvement over the original Mirels score (AUC = 0.853). Decision curve analysis was used to quantify the relative risks of identifying patients that would fracture (TP, true positives) and those erroneously predicted to fracture (FP, false positives) for the original and modified Mirels scoring systems. The net benefit of the scoring system weighed the benefits (TP) and harms (FP) on the same scale. At a threshold probability of fracture of 10%, use of the modified Mirels scoring reduced the number of false positives by 17-20% compared to Mirels scoring. CONCLUSIONS: A modified Mirels scoring system, informed by detailed analysis of the influence of lesion location, improved the ability to predict impending pathological fractures of the proximal femur for patients with metastatic bone disease. Decision curve analysis is a useful tool to weigh costs and benefits concerning fracture risk and could be combined with other patient/clinical factors that contribute to clinical decision making.

Academic Orthopaedics As a Driver of Gender Diversity in the Orthopaedic Workforce: A Review of 4,519 Orthopaedic Faculty Members.

BACKGROUND: The purpose of this study was to perform a cross-sectional analysis on the gender composition of practicing academic orthopaedic surgeons using three databases composed of clinical orthopaedic surgeons. METHODS: A comprehensive database of 4,519 clinically active academic orthopaedic surgeons was compiled for this study after the review of publicly available data. The complied data set was evaluated alongside orthopaedic databases obtained from the 2017 Association of American Medical Colleges (AAMC) Faculty Administrative Management Online User System and the 2016 American Academy of Orthopaedic Surgery (AAOS) Orthopaedic Practice in the US census representing the entire academy membership orthopaedic workforce. Gender status was obtained and compared between the three databases. RESULTS: Of the 4,519 clinically active academic orthopaedic surgeons analyzed, 435 (10%) were female compared with 19% for the AAMC faculty database and 7% for the AAOS members. Fourteen percent of women had achieved the rank of professor compared with 25% of the men (P < 0.001). AAMC faculty had a significantly higher percentages of female representation compared with both the clinical faculty (19% versus 10%; P < 0.001) and AAOS members (19% versus 7%; P < 0.001). CONCLUSION: Despite multiple initiatives designed to increase diversity, the 7% female representation in the orthopaedic workforce identified in this study remains markedly lower than other medical and surgical specialties. A higher percentage of women were associated with the AAMC orthopaedic faculty compared with clinically active female surgeons at these institutions. Academic orthopaedic surgeons had greater female representation than the general orthopaedic workforce, highlighting the importance of training institutions at promoting gender equity.

Predicting Fracture Risk in Patients with Metastatic Bone Disease of the Femur: A Pictorial Review Using Three Different Techniques.

One of the key roles of an orthopedic surgeon treating metastatic bone disease (MBD) is fracture risk prediction. Current widely used impending fracture risk tools such as Mirels scoring lack specificity. Two newer methods of fracture risk prediction, CT-based structural rigidity analysis (CTRA) and finite element analysis (FEA), have each been shown to be more accurate than Mirels. This case series illustrates comparative Mirels, CTRA, and FEA for 8 femurs in 7 subjects. These cases were selected from a much larger data set to portray examples of true positives, true negatives, false positives, and false negatives as defined by CTRA relative to the fracture outcome. Case illustrations demonstrate comparative Mirels and FEA. This series illustrates the use, efficacy, and limitations of these tools. As all current tools have limitations, further work is needed in refining and developing fracture risk prediction.

Diversity among academic orthopedic shoulder and elbow surgery faculty in the United States.

BACKGROUND: The purpose of this study was to perform a cross-sectional analysis of diversity among academic shoulder and elbow surgeons in the United States. METHODS: US shoulder and elbow surgeons who participated in shoulder and elbow fellowship and/or orthopedic surgery resident education as of November 2018 were included. Demographic data (age, gender, race), practice setting, years in practice, academic rank, and leadership roles were collected through publicly available databases and professional profiles. Descriptive statistics were performed and findings were compared between different racial and gender groups. Statistical significance was set at P <.05. RESULTS: A total of 186 orthopedic shoulder and elbow surgeons were identified as participating in shoulder and elbow fellowship and/or orthopedic surgery residency education. Overall, 83.9% were white, 14.5% were Asian, 1.1% were Hispanic, 0.5% were an other race, and 0% were African American. In addition, 94.6% of surgeons were male, whereas 5.4% were female. Further, 64.5% of all surgeons had been in practice for >10 years, and 39.2% worked in an urban setting. Less than half (40.3%) of the surgeons practicing primarily at academic institutions held a professor rank. White surgeons had a significantly greater time in practice vs. nonwhite surgeons (mean 18.8 vs. 12.6 years, P < .01) and were more likely to hold a professor rank (44.0% vs. 21.7%, P = .04). CONCLUSION: Racial and gender diversity among US shoulder and elbow surgeons who participate in fellowship and residency education is lacking. Hispanic, African American, and female surgeons are underrepresented. Efforts should be made to identify the reasons for these deficiencies and address them to further advance the field of orthopedic shoulder and elbow surgery.

Lack of Additional Advanced Graduate Training by Orthopaedic Surgeons in Academic Practice: Current Employment and Recruitment Trends.

BACKGROUND: Orthopaedic surgery is ever changing and depends on diverse technical and intellectual skill sets. The purpose of the current study was to evaluate the percentage of academic orthopaedic surgeons with additional graduate degrees in the United States. METHODS: Data including advanced degree(s) (eg, PhD, MS, MBA, MPH, JD, and DVM), academic rank, leadership position, subspecialty, years since training completion, and sex were collected from websites for all academic orthopaedic surgery departments in the United States. Univariate analyses were performed to evaluate for differences in demographic data based on the advanced degree status. Data from the National Resident Matching Program (NRMP) were used to characterize graduate degree-holding US senior medical students who ranked orthopaedic surgery first relative to peers without additional advanced degrees and to applicants who ranked other specialties first. RESULTS: Of 4,519 faculty at 175 academic orthopaedic surgery departments in the United States, 7.1% held a graduate degree in addition to a medical doctorate. There was no difference in the percentage of faculty who held departmental leadership positions (P = 0.62) or who were full professors (P = 0.66) based on holding an additional graduate degree. Of 678 US senior applicants who ranked orthopaedic surgery first and successfully matched into the specialty in 2018, 12.5% held an additional graduate degree and 1.3% were MD-PhDs. Orthopaedic surgery had the second lowest percentage of matched medical students with additional advanced degrees, which was significantly lower than the top 10 specialties (range 16.1% to 21.6%; P < 0.05). Orthopaedic surgery recruited 1.6% of all MD-PhD applicants in 2018. DISCUSSION: Few academic orthopaedic surgery faculty and admitted orthopaedic residency candidates have additional graduate school training. The low percentage of orthopaedic faculty and trainees with additional advanced degrees relative to other specialties may represent a missed opportunity to recruit individuals with diverse skills to advance the field of orthopaedic surgery.

Combination therapy in the Col1a2G610C mouse model of Osteogenesis Imperfecta reveals an additive effect of enhancing LRP5 signaling and inhibiting TGFß signaling on trabecular bone but not on cortical bone.

Enhancing LRP5 signaling and inhibiting TGFß signaling have each been reported to increase bone mass and improve bone strength in wild-type mice. Monotherapy targeting LRP5 signaling, or TGFß signaling, also improved bone properties in mouse models of Osteogenesis Imperfecta (OI). We investigated whether additive or synergistic increases in bone properties would be attained if enhanced LRP5 signaling was combined with TGFß inhibition. We crossed an Lrp5 high bone mass (HBM) allele (Lrp5A214V) into the Col1a2G610C/+ mouse model of OI. At 6-weeks-of-age we began treating mice with an antibody that inhibits TGFß1, ß2, and ß3 (mAb 1D11), or with an isotype-matched control antibody (mAb 13C4). At 12-weeks-old, we observed that combining enhanced LRP5 signaling with inhibited TGFß signaling produced an additive effect on femoral and vertebral trabecular bone volumes, but not on cortical bone volumes. Although enhanced LRP5 signaling increased femur strength in a 3-point bending assay in Col1a2G610C/+ mice, femur strength did not improve further with TGFß inhibition. Neither enhanced LRP5 signaling nor TGFß inhibition, alone or in combination, improved femur 3-point-bending post-yield displacement in Col1a2G610C/+ mice. These pre-clinical studies indicate combination therapies that target LRP5 and TGFß signaling should increase trabecular bone mass in patients with OI more than targeting either signaling pathway alone. Whether additive increases in trabecular bone mass will occur in, and clinically benefit, patients with OI needs to be determined.