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author:("Ahn, jaime")
1.  Applying Evidence-Based Medicine Principles to Hip Fracture Management 
Frontiers in Surgery  2014;1:40.
Bone has the capacity to regenerate and not scar after injury – sometimes leaving behind no evidence at all of a prior fracture. As surgeons capable of facilitating such healing, it becomes our responsibility to help choose a treatment that minimizes functional deficits and residual symptoms. And in the case of the geriatric hip fracture, we have seen the accumulation of a vast amount of evidence to help guide us. The best method we currently have for selecting treatment plans is by the practice of evidence-based medicine. According to the now accepted hierarchy, the best is called Level I evidence (e.g., well performed randomized controlled trials) – but this evidence is best only if it is available and appropriate. Lower forms of accepted evidence include cohort studies, case control studies, case series, and case reports, and last, expert opinion – all of which can be potentially instructive. The hallmark of evidence-based treatment is not so much the reliance on evidence in general, but to use the best available evidence relative to the particular patient, the clinical setting and surgeon experience. Correctly applied, varying forms of evidence each have a role in aiding surgeons offer appropriate care for their patients – to help them best fix the fracture.
PMCID: PMC4286989  PMID: 25593964
fracture; orthopedic trauma; evidence-based medicine; surgical decision making; level of evidence; expert opinion; collective intelligence
2.  T-condylar fractures of the distal humerus in children: does early motion affect final range of motion? 
T-condylar fractures of the distal humerus are infrequent injuries in children. There are little data regarding outcomes in this age group. The adult literature demonstrates a high rate of postinjury stiffness. We describe a large series of T-condylar fractures in children and set out to identify factors that influence the postoperative range of motion (ROM) in children. Our hypothesis was that starting motion early (<3 weeks) would favorably influence the postoperative ROM.
Patients were identified based on the Current Procedural Terminology (CPT) code for ORIF of supracondylar distal humerus fractures with intracondylar extension (24546). Patient records and radiographs were reviewed to determine the demographics, fracture characteristics, surgical approach and fixation, and postoperative immobilization time. Our outcome measure was ROM in flexion/extension at 3 months, 6 months, 1 year, and final follow-up. Patients were analyzed by Morrey’s criteria of −30° extension and 130° flexion to assess for postoperative elbow stiffness.
Thirty-eight potential patients from 1992 to 2010 were identified with specific T-condylar patterns. Twelve patients were excluded due to insufficient follow-up or lack of final ROM data. Our cohort included 26 patients (average age 13.4 years). The average postoperative immobilization time was 3.4 weeks (range 0.9−12 weeks). At the final follow-up, patients had −12° average extension and 130° average flexion. Nine patients (35 %) were stiff and 17 patients (65 %) had functional motion postoperatively. At 3 and 6 months, starting motion early yielded better flexion and extension ROM. Late-motion patients obtained similar results at the 1-year follow-up. Open fractures, gender, and age were all not significantly associated with elbow stiffness in our series, given the limited numbers.
Early ROM was associated with an earlier gain of functional motion without clear adverse consequences. Despite similar findings at the final follow-up, practitioners should consider instituting early ROM protocols to decrease the duration of stiffness and potential disability for the child and the family.
PMCID: PMC3965770  PMID: 24643671
T-condylar; T-condylar distal humerus fractures; Upper extremity fractures
3.  Heterotopic Ossification in Orthopaedic Trauma 
Journal of orthopaedic trauma  2012;26(12):684-688.
Heterotopic ossification (HO) can be defined as the pathological formation of bone in extra-skeletal tissues. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO and traumatic conditions associated with the development of HO. This research has advanced our understanding of this disease and helped to clarify evidence-based approaches to both the prophylaxis and treatment of HO. This article reviews the literature on these topics with a focus on their application in orthopaedic trauma.
PMCID: PMC3504617  PMID: 23010648
4.  Fractures in Brief: Olecranon Fractures 
PMCID: PMC3492613  PMID: 22723241
5.  Bisphosphonate-associated Femur Fractures Have High Complication Rates with Operative Fixation 
Bisphosphonate-associated femur fractures have been well described but the preoperative patient factors, treatment modalities, and complications of treatment are unclear.
We asked whether a diagnosis of osteoporosis, the characteristic radiographic features of bisphosphonate-related femur fractures, and complication rates differed in patients with operatively treated femoral shaft fractures receiving bisphosphonates and in patients not receiving bisphosphonates.
We retrospectively reviewed 43 patients with bisphosphonate-associated femoral shaft fractures (including subtrochanteric) from 2002 to 2008 and 20 patients with similar fractures but not treated with bisphosphonates. Similar implants were used in both groups, but a greater number of adjuvants were used in the bisphosphonate cohort. We recorded preoperative osteoporosis and radiographic findings of the characteristic bisphosphonate femur fracture and early complications. The minimum followup was 5 months (mean, 29 months; range 5–60 months).
Preoperatively a greater percentage of patients treated with bisphosphonates had confirmed osteoporosis than those not treated with bisphosphonates (24% versus 5%, respectively), a greater percentage had a proximal fracture location (48% versus 40%, respectively), and their mean cortex to shaft diameter ratio was greater (24% versus 15%, respectively). The bisphosphonate cohort had a higher rate of intraoperative fractures (21% versus 0%) and postoperative plate failures (30% versus 0%).
Despite low rates of other risk factors and ample use of biologic adjuvants, patients treated with bisphosphonates having femur fractures have more complications.
Level of Evidence
Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC3392377  PMID: 22669553
6.  Systemic Inhibition of Canonical Notch Signaling Results in Sustained Callus Inflammation and Alters Multiple Phases of Fracture Healing 
PLoS ONE  2013;8(7):e68726.
The Notch signaling pathway is an important regulator of embryological bone development, and many aspects of development are recapitulated during bone repair. We have previously reported that Notch signaling components are upregulated during bone fracture healing. However, the significance of the Notch pathway in bone regeneration has not been described. Therefore, the objective of this study was to determine the importance of Notch signaling in regulating bone fracture healing by using a temporally controlled inducible transgenic mouse model (Mx1-Cre;dnMAMLf/-) to impair RBPjκ-mediated canonical Notch signaling. The Mx1 promoter was synthetically activated resulting in temporally regulated systemic dnMAML expression just prior to creation of bilateral tibial fractures. This allowed for mice to undergo unaltered embryological and post-natal skeletal development. Results showed that systemic Notch inhibition prolonged expression of inflammatory cytokines and neutrophil cell inflammation, and reduced the proportion of cartilage formation within the callus at 10 days-post-fracture (dpf) Notch inhibition did not affect early bone formation at 10dpf, but significantly altered bone maturation and remodeling at 20dpf. Increased bone volume fraction in dnMAML fractures, which was due to a moderate decrease in callus size with no change in bone mass, coincided with increased trabecular thickness but decreased connectivity density, indicating that patterning of bone was altered. Notch inhibition decreased total osteogenic cell density, which was comprised of more osteocytes rather than osteoblasts. dnMAML also decreased osteoclast density, suggesting that osteoclast activity may also be important for altered fracture healing. It is likely that systemic Notch inhibition had both direct effects within cell types as well as indirect effects initiated by temporally upstream events in the fracture healing cascade. Surprisingly, Notch inhibition did not alter cell proliferation. In conclusion, our results demonstrate that the Notch signaling pathway is required for the proper temporal progression of events required for successful bone fracture healing.
PMCID: PMC3701065  PMID: 23844237
7.  In Brief: Closed Tibial Shaft Fractures 
PMCID: PMC3210280  PMID: 21932100
8.  In Brief: Lisfranc Fracture Dislocations 
PMCID: PMC3111796  PMID: 20878282
9.  In Brief: Patellar Fractures 
PMCID: PMC3048243  PMID: 20740335
10.  In Brief: Pilon Fractures 
PMCID: PMC3018216  PMID: 20694535
11.  In Brief: Fractures in Brief: Calcaneal Fractures 
PMCID: PMC2974888  PMID: 20387018
12.  Crowd Intelligence for the Classification of Fractures and Beyond 
PLoS ONE  2011;6(11):e27620.
Medical diagnosis, like all products of human cognition, is subject to error. We tested the hypothesis that errors of diagnosis in the realm of fracture classification can be reduced by a consensus (group) diagnosis; and that digital imaging and Internet access makes feasible the compilation of a diagnostic consensus in real time.
Twelve orthopaedic surgeons were asked to evaluate 20 hip radiographs demonstrating a femoral neck fracture. The surgeons were asked to determine if the fractures were displaced or not. Because no reference standard is available, the maximal accuracy of the diagnosis of displacement can be inferred from inter-observer reliability: if two readers disagree about displacement, one of them must be wrong. That method was employed here. Additionally, virtual reader groups of 3 and 5 individual members were amalgamated, with the response of those groups defined by majority vote. The purpose of this step was to see if increasing the number of readers would improve accuracy. In a second experiment, to study the feasibility of amassing a reader group on the Internet in real time, 40 volunteers were sent 10 periodic email requests to answer questions and their response times were assessed.
The mean kappa coefficient for individual inter-observer reliability for the diagnosis of displacement was 0.69, comparable to prior published values. For 3-member virtual reader groups, inter-observer reliability was 0.77; and for 5-member groups, it was 0.80. In the experiment studying the feasibility of amassing a reader group in real time, the mean response time was 594 minutes. For all cases, a 9-member group (theoretically 99% accurate) was amassed in 135.8 minutes or less.
Consensus may improve diagnosis. Amassing a group for this purpose on the Internet is feasible.
PMCID: PMC3223187  PMID: 22132118
13.  In Brief: Fractures in Brief: Femoral Neck Fractures 
PMCID: PMC2865592  PMID: 20224957
14.  In Brief: Fractures in Brief: Intertrochanteric Hip Fractures 
PMCID: PMC2853662  PMID: 20195807
15.  Are Away Rotations Critical for a Successful Match in Orthopaedic Surgery? 
Surveys have suggested one of the most important determinants of orthopaedic resident selection is completion of an orthopaedic clerkship at the program director’s institution. The purpose of this study was to further elucidate the significance of visiting externships on the resident selection process. We retrospectively reviewed data for all medical students applying for orthopaedic surgery residency from six medical schools between 2006 and 2008, for a total of 143 applicants. Univariate and multivariate regression analyses were used to compare students who matched successfully versus those who did not in terms of number of away rotations, United States Medical Licensing Examination® scores, class rank, and other objective factors. Of the 143 medical students, 19 did not match in orthopaedics (13.3%), whereas the remaining 124 matched. On multiple logistic regression analysis, whether a student did more than one home rotation, how many away rotations a student performed, and United States Medical Licensing Examination® Step 1 score were factors in the odds of match success. Orthopaedic surgery is one of the most competitive specialties in medicine; the away rotation remains an important factor in match success.
PMCID: PMC2772936  PMID: 19582529
16.  Systematic Review of Cemented and Uncemented Hemiarthroplasty Outcomes for Femoral Neck Fractures 
Although hemiarthroplasties are an important treatment for femoral neck fractures, the literature does not provide a clear approach for selecting the implant fixation method. Therefore, we performed a systematic search of the medical literature and identified 11 prospective and retrospective studies that compared results between cemented and uncemented femoral implant fixation methods. After independent blind data extraction, we compared variables between cemented and uncemented cohorts using two different meta-analysis models. Pooled data represented 1632 cemented and 981 uncemented hemiarthroplasties (average age of patients, 78.9 and 77.5 years, respectively). The average operating room times and blood loss volumes were 95 minutes and 467 mL, respectively, for the cemented and 80 minutes and 338 mL for the uncemented cohorts. Postoperative mortality rates, overall complications, and pain were similar between the two cohorts. Despite a few potential trends, we found few statistical differences between cemented and uncemented techniques based on reported outcome measurements. In addition, inspection of this literature underscored the lack of and need for consistent and standardized reporting of outcome variables regarding these procedures.
Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
Electronic supplementary material
The online version of this article (doi:10.1007/s11999-008-0368-3) contains supplementary material, which is available to authorized users.
PMCID: PMC2584290  PMID: 18651200
17.  Streamlining the Evaluation of Low Back Pain in Children 
The workup of low back pain in children often results in overimaging so as not to miss organic back pain. The primary goal of this study was to identify which combination of imaging modalities provides the most sensitive and specific screening protocol for children with low back pain. Medical records from 100 consecutive patients between 2 and 18 years of age presenting with low back pain, without night pain or constitutional symptoms, were evaluated. A hyperextension test combined with a radiograph showed a negative predictive value of 0.81 and sensitivity of 0.90. The addition of a bone scan was highly effective in achieving good negative predictive value and sensitivity. Bone scans had perfect negative predictive value and sensitivity when symptom duration was less than 6 weeks. We identified a set of factors that is highly predictive for distinguishing organic back pain from mechanical back pain. Painless hyperextension combined with negative anteroposterior, lateral, and oblique lumbar radiographs and magnetic resonance images predicts mechanical back pain. For patients with nonneurologic back pain of less than 6 weeks duration, bone scan is the most useful screening test because it is accurate, accessible, inexpensive, and unlikely to require sedation.
Level of Evidence: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC2584263  PMID: 18553213

Results 1-17 (17)