Michael Zlowodzki

Steadman Philippon Research Institute, Vail, Colorado, United States

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Publications (57)93.25 Total impact

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    ABSTRACT: The purpose of this study was to evaluate the maximum insertion torque of cancellous bone screws in osteoporotic proximal femurs with and without the use of washers.
    Journal of orthopaedic trauma. 06/2014;
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    ABSTRACT: OBJECTIVES:: The purpose of this investigation is to define the location and frequency of tibia pilon fracture lines and impaction injury for the most severe variety (OTA/AO Type 43C3). PATIENTS/METHODS:: Using axial CT scan images, 38 consecutive OTA/AO Type 43C3 fractures treated by a single surgeon were analyzed. For each fracture, a map of the fracture lines and zones of comminution was drawn. Each map was digitized and graphically superimposed to create a compilation of fracture lines and zones of comminution. Based upon this compilation, major and minor fracture lines were identified and fracture patterns defined. Specifically, a basic Y pattern, constant across all patients, was identified where the stem of the Y went into the fibula incisura. All other fracture lines were considered secondary and these defined the comminution. RESULTS:: One hundred percent of major fracture lines involved the tibio-fibular joint and all exited medially in two general zones, anterior and posterior to the medial malleolus best described as a Y-shaped pattern. Therefore, three main fragments existed in every single case. Comminution was present in 36/38 (95%) cases and it was predominantly located centrally and in the antero-lateral quarter. CONCLUSIONS:: There is a consistent fracture pattern underlying the majority of OTA/AO Type 43C3 pilon fractures which could be defined as three main fragments, anterior, medial and posterior. These result from a major fracture line extending from the fibular incisura and exiting anterior and posterior to the medial malleolus. The comminution commonly distinguishing pilon fractures, occurs from secondary fracture lines through the apex of the plafond and in the anterolateral region. Knowledge of this constant pattern should influence surgical approaches and possibly implant design.
    Journal of orthopaedic trauma 01/2013; · 1.78 Impact Factor
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    ABSTRACT: Decision aids help physicians convey information to patients and enable patients to be involved in the decision-making process. There is a lack of use of decision aids in the orthopedic literature. The purpose of this study was to develop a decision board to elicit preferences for treatment of displaced femoral neck fractures in patients over 60 years old. We developed a decision board presenting descriptions and potential outcomes and complications of two treatment options, hemiarthroplasty (HA) and internal fixation (IF), for displaced femoral neck fractures. Five orthopedic surgeons evaluated the face and content validity of the decision board and 10 volunteers completed "scope tests" to determine the comprehensibility. We then presented the decision board to 108 study participants faced with the scenario of sustaining a displaced femoral neck fracture. Participants stated their preference for operative procedure and described the reasons for their choices. The decision board achieved good face and content validity. All participants in the scope tests appropriately switched their preference to the other modality when probabilities were altered. Most participants found the decision board easy to understand and helpful in making an informed decision. Also, most participants were satisfied with the amount of information presented and with the use of the decision board as a decision making tool. Sixty-one participants (56%) chose IF as their operative procedure of choice quoting less blood loss, shorter operative time, and less invasiveness as the top factors that contributed to this choice. Participants who preferred HA (44%) did so primarily due to the lower re-operation rate. The decision board is a useful and reliable tool to inform patients about the treatment options for displaced femoral neck fractures. They should be utilized by surgeons to incorporate patients' preferences into the decision-making process.
    Indian Journal of Orthopaedics 01/2012; 46(1):22-8. · 0.74 Impact Factor
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    ABSTRACT: The aim of this article is to provide a concise review of the basic science of extracorporeal shock wave therapy (ESWT) and to perform a systematic review of the literature for the use of ESWT in the treatment of fractures and delayed unions/nonunions. Articles in the English or German language were identified for the systematic review by searching PubMed-MEDLINE from 1966 until 2008, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, and relevant meeting abstracts from 2007 to 2008. Moreover, the bibliographies of the identified articles were reviewed. We included clinical outcome studies of ESWT in the treatment of fractures and delayed unions/nonunions. Reports with less than 10 patients were excluded. Nonunions after corrective osteotomies or arthrodeses were excluded. Sample size, level of evidence, definition of delayed union, definition of nonunion, time from injury to shock wave treatment, location of fracture, union rate, and complications were extracted from the identified articles. Data of 924 patients undergoing ESWT for delayed union/nonunion were extracted from 10 studies. All articles were graded as level 4 studies. The overall union rate was 76% (95% confidence interval 73%-79%). The union rate was significantly higher in hypertrophic nonunions than in atrophic nonunions. Data from level 4 studies suggest that shock wave therapy seems to stimulate the healing process in delayed unions/nonunions. However, further investigations are required.
    Journal of orthopaedic trauma 03/2010; 24 Suppl 1:S66-70. · 1.78 Impact Factor
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    ABSTRACT: Fractures of the scapula involve a unique and challenging set of considerations, which must be understood to provide optimal treatment. The primary goal of this study was to create a frequency map of a series of surgically treated scapular fractures that specifically involved the scapular body and/or neck. A prospective database was used in the collection of consecutive radiographic imaging studies of patients undergoing operative treatment of scapular fractures. Scanned three-dimensional computed tomography images were superimposed and oriented to fit a model scapular template. Size dimensions were normalized by aligning specific scapular landmarks. Fracture lines were identified and traced over the combined three-dimensional computed tomography model to create a scapular fracture map. Of ninety fractures that met the criteria for inclusion, 68% involved the inferior aspect of the glenoid neck and 71% involved the superior vertebral border. Seventeen percent of the patterns included articular extension, and 22% of the fractures entered the spinoglenoid notch. Of fractures involving the inferior aspect of the glenoid neck at the lateral scapular border, 84% traversed medially to exit just inferior to the medial extent of the scapular spine, and 59% of these inferior neck fractures also had propagation to the inferior third of the vertebral border. Among the fractures involving the spinoglenoid notch, the most common pattern was demonstrated by coexisting fracture lines; 60% of the fractures of the spinoglenoid notch exited just inferior to the glenoid, 65% extended to the superior-medial vertebral border, and 45% extended to the inferior-medial vertebral border. In contrast, articular fractures did not follow predictable patterns; they demonstrated the greatest variability in trajectory, which was almost random, and there was a wide distribution of exit points along the vertebral border. Surgically treated scapular fractures display very common patterns. The most common pattern is the lateral border fracture immediately inferior to the glenoid, which extends to the superior vertebral border in more than two-thirds of cases. A smaller proportion of scapular fractures enter the spinoglenoid notch or the articular surface. There is great variation in the patterns of fractures involving the articular surface.
    The Journal of Bone and Joint Surgery 10/2009; 91(9):2222-8. · 3.23 Impact Factor
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    ABSTRACT: Concerns about the Gamma nail have largely been fueled by early randomized trials and meta-analyses suggesting an increased risk of subsequent femoral shaft fractures when compared with compression hip screws. Whereas meta-analyses favor compression hip screws over first-generation Gamma nails, little is known as to whether the newer Gamma nail designs and the improved learning curve associated with the implants have reduced the risk of femoral shaft fracture. The current meta-analysis aimed to explore the effects of time and Gamma Nail design on the risks of femoral shaft fracture after treatment of extracapsular hip fractures. We searched computerized databases (Medline, Cochrane, and SciSearch) for published randomized clinical trials from 1969 to 2002, and we identified additional studies through hand searches of major orthopedic journals, bibliographies of major orthopedic texts, and personal files. Two investigators independently graded study quality and abstracted relevant data. We abstracted information on subsequent femoral shaft fracture rates from studies. We pooled data using a random-effects model and tested for heterogeneity using the I test. We conducted sensitivity analyses by date and by generation of the Gamma nail. We further conducted a cumulative meta-analysis to explore the treatment effect over time. We identified 25 relevant randomized trials from 1991 to 2005. In earlier studies (N = 1585 patients), Gamma nails increased the risk of femoral shaft fracture 4.5 times compared with a compression hip screw (95% confidence interval: 1.78-11.36, P = 0.0014, I(2) = 0%). However, among the most recent studies (2000-2005), Gamma nails did not significantly increase femoral shaft fracture risk (relative risk = 1.65, 95% confidence interval: 0.50-5.44, P = 0.41, I(2) = 0%). The most recent study (2005) found no difference in femoral fracture rates (relative risk = 1.03, 95% confidence interval = 0.06-16.2, P = 0.99). Our meta-analysis of randomized trials suggests that previous concerns about increased femoral shaft fracture risk with Gamma nails have been resolved with improved implant design and improved learning curves with the device. Earlier meta-analyses and randomized trials should be interpreted with caution in light of more recent evidence.
    Journal of orthopaedic trauma 08/2009; 23(6):460-4. · 1.78 Impact Factor
  • Michael Zlowodzki, Mohit Bhandari
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    ABSTRACT: This article focuses on items to consider when selecting outcome measures for a clinical study. The choice of outcome measures depends largely on the research question and the study design. Sample-size requirements can vary greatly, depending on the type and the number of outcome measures selected. In this paper, we review the differences between categorical and continuous outcomes as well as the differences between primary and secondary outcomes and we discuss the concept of minimally important differences and the problems associated with composite outcomes. We also provide instruction on how to conduct and present a sample-size calculation.
    The Journal of Bone and Joint Surgery 06/2009; 91 Suppl 3:35-40. · 3.23 Impact Factor
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    ABSTRACT: It is unclear whether current practice reflects current evidence on predictors of clinically important outcomes like mortality and fixation failure. Knowledge of predictors of outcome can and should influence treatment decisions and can subsequently improve outcomes. We hypothesized that there is evidence about the significance of predictors of outcome not being considered in the decision making process in the treatment of hip fractures because many surgeons are unaware of it. We surveyed 298 North American and European orthopedic surgeons to examine their training and experience and their opinion on the relative importance of predictors of outcome of femoral neck fracture treatment. We compared the results with the highest level of therapeutic and prognostic evidence currently available. Surgeons' perceptions about the importance of the quality of fracture reduction, patient comorbidities, degree of fracture displacement, dementia, and prefracture walking ability were justified by the current literature. However, we further identified a number of variables deemed unimportant to surgeons that have evidence to support their use in managing patients with hip fractures, including the type of anesthesia as a modifiable variable. In contrast to surgeons' perceptions, the available evidence suggests regional anesthesia is associated with a lower mortality risk than general anesthesia.
    Orthopedics 05/2009; 32(4). · 1.05 Impact Factor
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    ABSTRACT: We have studied the effect of shortening of the femoral neck and varus collapse on the functional capacity and quality of life of patients who had undergone fixation of an isolated intracapsular fracture of the hip with cancellous screws. After screening 660 patients at four university medical centres, 70 patients with a mean age of 71 years (20 to 90) met the inclusion criteria. Overall, 66% (46 of 70) of the fractures healed with > 5 mm of shortening and 39% (27 of 70) with > 5 degrees of varus. Patients with severe shortening of the femoral neck had significantly lower short form-36 questionnaire (SF-36) physical functioning scores (no/mild (<5 mm) vs severe shortening (> 10 mm); 74 vs 42 points, p < 0.001). A similar effect was noted with moderate shortening, suggesting a gradient effect (no/mild (< 5 mm) vs moderate shortening (5 to 10 mm); 74 vs 53 points, p = 0.011). Varus collapse correlated moderately with the occurrence of shortening (r = 0.66, p < 0.001). Shortening also resulted in a significantly lower EuroQol questionnaire (EQ5D) index scores (p = 0.05). In a regression analysis shortening of the femoral neck was the only significant variable predictive of a low SF-36 physical functioning score (p < 0.001).
    Journal of Bone and Joint Surgery - British Volume 11/2008; 90(11):1487-94. · 2.69 Impact Factor
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    ABSTRACT: Available options to fill fracture voids include autogenous bone, allograft bone, and synthetic bone materials. The objective of this meta-analysis was to determine whether the use of calcium phosphate bone cement improves clinical and radiographic outcomes and reduces fracture complications as compared with conventional treatment (with or without autogenous bone graft) for the treatment of fractures of the appendicular skeleton in adult patients. Multiple databases, online registers of randomized controlled trials, and the proceedings of the meetings of major national orthopaedic associations were searched. Published and unpublished randomized controlled trials were included, and data on methodological quality, population, intervention, and outcomes were abstracted in duplicate. Data were pooled across studies, and relative risks for categorical outcomes and weighted mean differences for continuous outcomes, weighted according to study sample size, were calculated. Heterogeneity across studies was determined, and sensitivity analyses were conducted. We identified eleven published and three unpublished randomized controlled trials. Of the fourteen studies, six involved distal radial fractures, two involved femoral neck fractures, two involved intertrochanteric femoral fractures, two involved tibial plateau fractures, one involved calcaneal fractures, and one involved multiple types of metaphyseal fractures. All of the studies evaluated the use of calcium phosphate cement for the treatment of metaphyseal fractures occurring primarily through trabecular, cancellous bone. Autogenous bone graft was used in the control group in three studies, and no graft material was used in the remaining studies. Patients managed with calcium phosphate had a significantly lower prevalence of loss of fracture reduction in comparison with patients managed with autograft (relative risk reduction, 68%; 95% confidence interval, 29% to 86%) and had less pain at the fracture site in comparison with controls managed with no graft (relative risk reduction, 56%; 95% confidence interval, 14% to 77%). We were unable to compare pain at the bone-graft donor site between the studies because of methodological reasons. Three studies independently demonstrated improved functional outcomes when the use of calcium phosphate was compared with the use of no grafting material. The use of calcium phosphate bone cement for the treatment of fractures in adult patients is associated with a lower prevalence of pain at the fracture site in comparison with the rate in controls (patients managed with no graft material). Loss of fracture reduction is also decreased in comparison with that in patients managed with autogenous bone graft.
    The Journal of Bone and Joint Surgery 06/2008; 90(6):1186-96. · 3.23 Impact Factor
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    ABSTRACT: There is no consensus on the best treatment for periprosthetic supracondylar fracture. We systematically summarized and compared results of different fixation techniques in the management of acute distal femur fractures above a total knee arthroplasty (TKA). Several databases were searched (Medline, Cochrane library, OTA and AAOS abstract databases) and baseline and outcome parameters were abstracted. We extracted data from 29 case series with a total of 415 fractures. The following outcomes were noted: a nonunion rate of 9%, a fixation failure rate of 4%, an infection rate of 3%, and a revision surgery rate of 13%. Retrograde nailing was associated with relative risk reduction (RRR) of 87% (p = 0.01) for developing a nonunion and 70% (p = 0.03) for requiring revision surgery compared to traditional (non-locking) plating methods. Point estimates also suggested risk reductions for locking plates, although these were not statistically significant (57% for nonunion, p = 0.2; 43% for revision surgery, p = 0.23) compared to traditional plating. RRRs for nonunion and revision surgery were also statistically significantly lower for retrograde nailing and locking plates compared to nonoperative treatment. Modern-day treatment methods are superior to conventional treatment options in the management of distal femur fractures above TKAs. The results should be interpreted with caution, due to the lack of randomized controlled trials and the possible selection bias in case series.
    Acta Orthopaedica 03/2008; 79(1):22-7. · 2.74 Impact Factor
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    ABSTRACT: Shortening of the femoral neck after fracture fixation with multiple parallel screws decreases the moment arm for the abductor muscles of the hip. This study aimed to assess the incidence of femoral neck shortening quantitatively and qualitatively in patients with femoral neck fractures treated with multiple cannulated screws, and to investigate its influence on functional outcome. We conducted an observational study in a consecutive series of 56 patients with united fractures of the femoral neck treated with multiple cancellous screws. The latest anterior-posterior radiograph of the fractured hip was compared with that of the contralateral uninjured hip. After scanning and electronically overlapping those radiographs, femoral neck shortening was assessed. All identified patients were contacted and the Short Form-36 (SF-36) functional outcome questionnaire was administered. The shortening rate was 31% for undisplaced (14 of 45) and 27% for displaced fractures (3 of 11). The average abductor moment arm shortening was 10 +/- 4 mm. The average femur length decrease was 8 +/- 5 mm. In all other patients, abductor moment arm as well as femur length measurements were within 3 mm of the contralateral side and considered not to be shortened. Thirteen patients completed the SF-36 questionnaire (12 of 13 undisplaced fractures; all 13 with good fracture reduction). Patients with shortened fractures (8 of 13) had significantly lower Physical Functioning (p = 0.01) and Role Physical (p = 0.04) SF-36 subscores. Femoral neck shortening after femoral neck fracture fixation with multiple cancellous screws is common and it has a significant negative impact on physical functioning.
    The Journal of trauma 02/2008; 64(1):163-9. · 2.35 Impact Factor
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    ABSTRACT: There is currently no consensus on the optimal operative treatment for cubital tunnel syndrome. The objective of this meta-analysis of randomized, controlled trials was to evaluate the efficacy of simple decompression compared with that of anterior transposition of the ulnar nerve in the treatment of this condition. Multiple databases were searched for randomized, controlled trials on the outcome of operative treatment of cubital tunnel syndrome in patients who had not previously sustained trauma or undergone a surgical procedure involving the elbow. Two reviewers abstracted baseline characteristics, clinical scores, and motor nerve-conduction velocities independently. Data were pooled across studies, standard mean differences in effect sizes weighted by study sample size were calculated, and heterogeneity across studies was assessed. We identified four randomized, controlled trials comparing simple decompression with anterior ulnar nerve transposition (two submuscular and two subcutaneous). In three studies that included a total of 261 patients, a clinical scoring system was used as the primary clinical outcome. There were no significant differences between simple decompression and anterior transposition in terms of the clinical scores in those studies (standard mean difference in effect size = -0.04 [95% confidence interval = -0.36 to 0.28], p = 0.81). We did not find significant heterogeneity across these studies (I(2) = 34.2%, p = 0.22). Two reports, on a total of 100 patients, presented postoperative motor nerve-conduction velocities; they showed no significant differences between the procedures (standard mean difference in effect size = 0.24 [95% confidence interval -0.15 to 0.63] in favor of simple decompression, p = 0.23; I(2) = 0%, p = 0.9). The results of this meta-analysis suggest that there is no difference in motor nerve-conduction velocities or clinical outcome scores between simple decompression and ulnar nerve transposition for the treatment of ulnar nerve compression at the elbow in patients with no prior traumatic injuries or surgical procedures involving the affected elbow. Confidence intervals around the points of estimate were narrow, which probably exclude the possibility of clinically meaningful differences. These data suggest that simple decompression of the ulnar nerve is a reasonable alternative to anterior transposition for the surgical management of ulnar nerve compression at the elbow.
    The Journal of Bone and Joint Surgery 01/2008; 89(12):2591-8. · 3.23 Impact Factor
  • The Journal of Bone and Joint Surgery 01/2008; 90(11):1487. · 3.23 Impact Factor
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    ABSTRACT: The standard treatment for femoral shaft fractures is intramedullary nailing. However, there are indications for which plating can be performed either openly or in a submuscular manner. Between June 1996 and May 2002, two fellowship-trained orthopedic trauma surgeons treated 40 acute diaphyseal femoral fractures in 37 patients with use of plating techniques. Traditional open plating with emphasis on preservation of soft tissue integrity was performed exclusively before February 1999 (n = 19). After that time point, in all but one case (n = 21) submuscular plating techniques were used. No bone grafting was used for either group. A comparison of reduction quality, union rates, secondary interventions, and infection rates between traditional open reduction and internal fixation and submuscular fixation was performed (retrospective cohort study/evidence-based medicine (EBM)-level III). In assessing reduction quality, there were no malreductions in the traditional plating group and six in the submuscular plating group. There was one infection and one nonunion in the open reduction or internal fixation group. One infection was noted in the submuscular group. A 2.5% incidence of nonunion and a 5% incidence of infection (2 of 40; both in type III open fractures) were seen in this series of 40 femoral shaft fractures treated with plate application. Although the theoretical advantages of submuscular plating are well established, its utilization in the femoral shaft did not have a clear clinical advantage. In addition, its use appears to be more technically challenging, and is associated with a high rate of suboptimal reductions.
    The Journal of trauma 12/2007; 63(5):1061-5. · 2.35 Impact Factor
  • Acta Orthopaedica 11/2007; 78(5):598-609. · 2.74 Impact Factor
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    ABSTRACT: Complementary and alternative medicine (CAM) encompasses dietary supplements, herbs, homeopathic medicines, and other modalities. In light of prevalent CAM use, patient interest, increasing CAM expenditures, and possible interactions with traditional treatments or healing we identified the following in patients with fractures: prevalence of CAM use, the amount of money patients are spending on CAMs, and the number of patients who disclose CAM use to their orthopaedic surgeon and the reasons for withholding disclosure. Factors associated with CAM use were evaluated. Of the 322 patients with fractures surveyed, 35% were using CAMs. Of the patients using CAMs, 50% spent more than $25 per month. Fifty-five percent of the patients using CAMs had not discussed their CAM use with their orthopaedic surgeon citing "it was not an important issue to discuss." Factors associated with CAM use included level of education (odds ratio, 2.5; 95% confidence interval, 1.4-4.7) and psychiatric disorders (odds ratio, 2.5; 95% confidence interval, 1.3-5.0). To avoid possible interactions with traditional treatments and to identify side effects, surgeons should ask patients with fractures about CAM use in an unbiased fashion, as most patients will not voluntarily disclose their use.
    Clinical Orthopaedics and Related Research 11/2007; 463:173-8. · 2.79 Impact Factor
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    ABSTRACT: When using parallel screws for treatment of femoral neck fractures, shortening of the femoral neck might occur. Given the high revision surgery rates associated with parallel screws, we developed a questionnaire to explore (1) surgeons' viewpoints on difficulties in the fixation of femoral neck fractures, (2) their perception of the clinical importance of femoral neck shortening after internal fixation, and (3) their opinions regarding the ideal fixation device. Two hundred three surgeons responded. Eighty-three percent believed shortening of the femoral neck is common after screw fixation of femoral neck fractures; 89% believed shortening limits hip abductor function; and 69% believed shortening limits patients' physical function. When asked for features of the ideal implant for treatment of a femoral neck fracture, allowing compression across the fracture site on insertion and providing angular stability with a fixed-angle device to minimize shortening of the femoral neck were favored by 89% and 79% of the respondents, respectively. A plate with multiple nonparallel lag screws that can be locked into the plate might be a solution. However, the findings of this study are surgeons' opinions, which may or may not be confirmed by scientific evidence.
    Clinical Orthopaedics and Related Research 09/2007; 461:213-8. · 2.79 Impact Factor
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    Acta Orthopaedica 03/2007; 78(1):2-11. · 2.74 Impact Factor
  • Indian Journal of Orthopaedics 01/2007; 41(1):23-6. · 0.74 Impact Factor

Publication Stats

1k Citations
93.25 Total Impact Points

Institutions

  • 2014
    • Steadman Philippon Research Institute
      Vail, Colorado, United States
  • 2004–2013
    • Regions Hospital
      Saint Paul, Minnesota, United States
  • 2012
    • The University of Western Ontario
      • Department of Surgery
      London, Ontario, Canada
  • 2006–2009
    • University of Minnesota Twin Cities
      • Department of Orthopaedic Surgery
      Minneapolis, MN, United States
  • 2008
    • The University of Calgary
      • Division of Orthopedic Surgery
      Calgary, Alberta, Canada
  • 2005–2008
    • McMaster University
      Hamilton, Ontario, Canada
    • University of Minnesota Duluth
      Duluth, Minnesota, United States
  • 2005–2006
    • University of Pittsburgh
      • Department of Orthopaedic Surgery
      Pittsburgh, PA, United States
  • 2003–2006
    • Vanderbilt University
      • • Center for Evidence-based Medicine
      • • Division of Pediatric Surgery
      • • Department of Orthopaedic Surgery and Rehabilitation
      Nashville, MI, United States