Shiley Center for Orthopaedic Research and Education

San Diego, CA, United States

Shiley Center for Orthopaedic Research and Education

San Diego, CA, United States
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Falck-Ytter Y.,Case Western Reserve University | Francis C.W.,University of Rochester | Johanson N.A.,Drexel University | Curley C.,Case Western Reserve University | And 6 more authors.
Chest | Year: 2012

Background: VTE is a serious, but decreasing complication following major orthopedic surgery. This guideline focuses on optimal prophylaxis to reduce postoperative pulmonary embolism and DVT. Methods: The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement. Results: In patients undergoing major orthopedic surgery, we recommend the use of one of the following rather than no antithrombotic prophylaxis: low-molecular-weight heparin; fondaparinux; dabigatran, apixaban, rivaroxaban (total hip arthroplasty or total knee arthroplasty but not hip fracture surgery); low-dose unfractionated heparin; adjusted-dose vitamin K antagonist; aspirin (all Grade 1B); or an intermittent pneumatic compression device (IPCD) (Grade 1C) for a minimum of 10 to 14 days. We suggest the use of low-molecular-weight heparin in preference to the other agents we have recommended as alternatives(Grade 2C/2B), and in patients receiving pharmacologic prophylaxis, we suggest adding an IPCD during the hospital stay(Grade 2C). We suggest extending thromboprophylaxis for up to 35 days(Grade 2B). In patients at increased bleeding risk, we suggest an IPCD or no prophylaxis(Grade 2C). In patients who decline injections, we recommend using apixaban or dabigatran(all Grade 1B). We suggest against using inferior vena cava filter placement for primary prevention in patients with contraindications to both pharmacologic and mechanical thromboprophylaxis(Grade 2C). We recommend against Doppler(or duplex) ultrasonography screening before hospital discharge(Grade 1B). For patients with isolated low-erextremity injuries requiring leg immobilization, we suggest no thromboprophylaxis(Grade 2B). For patients undergoing knee arthroscopy without a history of VTE, we suggest no thromboprophylaxis (Grade 2B). Conclusions: Optimal strategies for thromboprophylaxis after major orthopedic surgery include pharmacologic and mechanical approaches. ©2012 American College of Chest Physicians.

Fregly B.J.,University of Florida | Besier T.F.,University of Auckland | Lloyd D.G.,Griffith University | Delp S.L.,Stanford University | And 3 more authors.
Journal of Orthopaedic Research | Year: 2012

Impairment of the human neuromusculoskeletal system can lead to significant mobility limitations and decreased quality of life. Computational models that accurately represent the musculoskeletal systems of individual patients could be used to explore different treatment options and optimize clinical outcome. The most significant barrier to model-based treatment design is validation of model-based estimates of in vivo contact and muscle forces. This paper introduces an annual "Grand Challenge Competition to Predict In Vivo Knee Loads" based on a series of comprehensive publicly available in vivo data sets for evaluating musculoskeletal model predictions of contact and muscle forces in the knee. The data sets come from patients implanted with force-measuring tibial prostheses. Following a historical review of musculoskeletal modeling methods used for estimating knee muscle and contact forces, we describe the first two data sets used for the first two competitions and summarize four subsequent data sets to be used for future competitions. These data sets include tibial contact force, video motion, ground reaction, muscle EMG, muscle strength, static and dynamic imaging, and implant geometry data. Competition participants create musculoskeletal models to predict tibial contact forces without having access to the corresponding in vivo measurements. These blinded predictions provide an unbiased evaluation of the capabilities and limitations of musculoskeletal modeling methods. The paper concludes with a discussion of how these unique data sets can be used by the musculoskeletal modeling research community to improve the estimation of in vivo muscle and contact forces and ultimately to help make musculoskeletal models clinically useful. Copyright © 2011 Orthopaedic Research Society.

Gortz S.,University of California at San Diego | De Young J.A.,Shiley Center for Orthopaedic Research and Education | Bugbee W.D.,Scripps Research Institute
Clinical Orthopaedics and Related Research | Year: 2010

Background Osteonecrosis is a complication of corticosteroid therapy with limited treatment options in young, active patients. These options include debridement, core decompression, osteotomy, allografting, and partial or total knee replacement. Few studies exist regarding the use of osteochondral allografts for treatment of steroidassociated osteonecrosis. Questions/purposes We asked if fresh osteochondral allografts would (1) heal to host bone in the presence of osteonecrosis, (2) provide a clinically meaningful decrease in pain and improvement in function, and (3) prevent or postpone the need for prosthetic arthroplasty. Patients and Methods Twenty-two patients (28 knees) who underwent osteochondral allografting for high-grade, corticosteroid-associated osteonecrosis were evaluated. Their average age was 24.3 years (range, 16-44 years). The mean graft surface area was 10.8 cm2 (range, 5.0- 19.0 cm2). Evaluation included a modified (for the knee) D'Aubigne' and Postel (18-point) score, International Knee Documentation Committee (IKDC), and Knee Society function scores. The minimum followup was 25 months (mean, 67 months; range, 25-235 months). Results Five knees failed. The graft survival rate was 89% (25 of 28). The mean D'Aubigne' and Postel score improved from 11.3 to 15.8; 19 of 25 (76%) had a score greater than 15. The mean IKDC pain score improved from 7.1 to 2.0, mean IKDC function score from 3.5 to 8.3, and mean Knee Society function score from 60.0 to 85.7. Conclusions Our data suggest osteochondral allografting is a reasonable salvage option for osteonecrosis of thefemoral condyles. TKA was avoided in 27 of the 28 of knees at last followup. Level of Evidence Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence. © The Association of Bone and Joint Surgeons® 2010.

Colwell Jr. C.W.,Shiley Center for Orthopaedic Research and Education | Chen P.C.,Shiley Center for Orthopaedic Research and Education | D'Lima D.,Shiley Center for Orthopaedic Research and Education
Clinical Biomechanics | Year: 2011

Background: Many patellofemoral complications such as anterior knee pain, subluxation, fracture, wear, and aseptic loosening after total knee arthroplasty are attributed to malrotation of the femoral component. Rotating-platform mobile bearings can reduce malrotation between the tibial and femoral components and may also improve patellofemoral maltracking. Methods: A computer model (LifeMOD/KneeSIM) of a weight-bearing deep knee bend was validated using cadaver knees tested in an Oxford-type knee rig. Changes in knee kinematics and patellofemoral forces were measured after femoral component malrotation of ± 3°. The effect of a rotating-bearing on these kinematics and forces was determined. Findings: In a fixed-bearing arthroplasty femoral component internal malrotation increased tibiofemoral internal rotation by 3.4°, and external malrotation increased tibiofemoral external rotation by 4°. Femoral component malrotation affected patellofemoral lateral shift by up to 2.5 mm, and patellofemoral lateral shear by up to 19 N. When the malrotated femoral component was tested against a rotating-bearing the change in tibiofemoral rotation and patellofemoral lateral shift was less than 1° and 1 mm respectively. The rotating-bearing reduced peak lateral shear by 7 N and peak medial shear by 17 N. Increasing the conformity of the rotating-bearing reduced changes in tibiofemoral rotation due to femoral malrotation and increased the net rotation of the bearing (by approximately 5°) during flexion. Interpretation: Our results are consistent with one randomized clinical outcome study and emphasize the value of computational modeling for preclinical design evaluation. It is important to continue to improve existing methodologies for accurate femoral component alignment especially in rotation. © 2010 Elsevier Ltd.

Bunn A.,Shiley Center for Orthopaedic Research and Education | Colwell Jr. C.W.,Shiley Center for Orthopaedic Research and Education | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education
Clinical Orthopaedics and Related Research | Year: 2012

Background: Factors affecting risk for impingement and dislocation can be related to the patient, implant design, or surgeon. While these have been studied independently, the impact of each factor relative to the others is not known. Questions/purposes: We determined the effect of three implant design factors, prosthetic placement, and patient anatomy on subject-specific ROM. Methods: We virtually implanted hip geometry obtained from 16 CT scans using computer models of hip components with differences in head size, neck diameter, and neck-shaft angle. A contact detection model computed ROM before prosthetic or bony impingement. We correlated anatomic measurements from pelvic radiographs with ROM. Results: When we implanted the components for best fit to the subject's anatomy or in the recommended orientation of 45° abduction and 20° anteversion, ROM was greater than 110° of flexion, 30° of extension, 45° of adduction-abduction, and 40° of external rotation. Changes in head size, neck diameter, and neck-shaft angle generated small gains (3.6°-6°) in ROM when analyzed individually, but collectively, we noted a more substantial increase (10°-17°). Radiographic measurements correlated only moderately with hip flexion and abduction. Conclusions: It is feasible to tailor implant placement to each patient to maximize bony coverage without compromising ROM. Once bony impingement becomes the restricting factor, further changes in implant design may not improve ROM. Radiographic measurements do not appear to have value in predicting ROM. © 2011 The Association of Bone and Joint Surgeons®.

Hoenecke Jr. H.R.,Shiley Center for Orthopaedic Research and Education | Hermida J.C.,Shiley Center for Orthopaedic Research and Education | Flores-Hernandez C.,Shiley Center for Orthopaedic Research and Education | D'Lima D.D.,Shiley Center for Orthopaedic Research and Education
Journal of Shoulder and Elbow Surgery | Year: 2010

Background/Hypothesis: The arthritic glenoid is typically in retroversion and restoration to neutral version is recommended. While a method for measurement of glenoid version using axial computed tomography (CT) has been reported and has been widely accepted, its accuracy and reproducibility has not been established. Methods: In 33 patients scheduled for shoulder arthroplasty, glenoid version and maximum wear of the glenoid articular surface were measured with respect to the scapular body axis on 2-dimensional- (2D) CT slices as well as on 3-dimensional- (3D) reconstructed models of the same CT slices. Results: Clinical CT scans were axially aligned with the patient's torso but were almost never perpendicular to the scapular body. The average absolute error in version measured on the 2D-CT slice passing through the tip of the coracoid was 5.1° (range, 0 - 16°, P < .001). On high-resolution 3D-CT reconstructions, the location of maximum wear was most commonly posterior and was missed on the clinical 2D-CT slices in 52% of cases. Conclusion: Error in measuring version and depth of maximum wear can substantially affect the determination of the degree of correction necessary in arthritic glenoids. Accurately measuring glenoid version and locating the direction of maximum wear requires a full 3D-CT reconstruction and analysis. © 2010 Journal of Shoulder and Elbow Surgery Board of Trustees.

Horton M.T.,Shiley Center for Orthopaedic Research and Education | Pulido P.A.,Shiley Center for Orthopaedic Research and Education | McCauley J.C.,Shiley Center for Orthopaedic Research and Education | Bugbee W.D.,Scripps Research Institute
American Journal of Sports Medicine | Year: 2013

Background: Primary fresh osteochondral allograft transplantation is a useful treatment option for osteochondral lesions in the knee. Clinical failure of primary osteochondral allograft transplantation may require further surgery, including revision osteochondral allograft transplantation. Purpose: To evaluate outcomes of patients who have undergone revision osteochondral allograft transplantation of the knee. Study Design: Case series; Level of evidence, 4. Methods: This series included 33 patients (33 knees) who underwent revision osteochondral allograft transplantation between 1983 and 2012, were at least 2 years out from surgery, and had a minimum 2-year follow-up. Clinical evaluations included the International Knee Documentation Committee pain, function, and total scores; Knee Society function score; and modified Merle d'Aubigné and Postel scale. Failure of the revision allograft was defined as conversion to partial or total knee arthroplasty. Results: The mean follow-up after revision osteochondral allograft transplantation was 10 years, with 75% of patients having more than 5 years' follow-up. Thirteen patients (39%) had failed results after revision osteochondral allograft transplantation, with a mean time to failure of 5.5 years. The remaining 20 patients (61%) had surviving revision allografts, with a mean graft survival of 10 years. Mean pain and function scores at the last follow-up were improved. Survivorship of the revision allograft was 61% at 10 years. Conclusion: Revision osteochondral allograft transplantation of the knee demonstrated acceptable clinical outcomes, although they were inferior to primary allograft transplantation procedures. Revision osteochondral allograft transplantation may be considered an option for patients with a failed primary osteochondral allograft. © 2013 The Author(s).

Levy Y.D.,Shiley Center for Orthopaedic Research and Education | Levy Y.D.,Scripps Research Institute | Ezzet K.A.,Scripps Research Institute
Journal of Arthroplasty | Year: 2013

Metal-on-metal (MoM) bearings for total hip arthroplasty (THA) have come under scrutiny with reports of high failure rates. Clinical outcome studies with several commercially available MoM THA bearings remain unreported. We evaluated 78 consecutive MoM THAs from a single manufacturer in 68 patients. Sixty-six received cobalt-chrome (CoCr) monoblock and 12 received modular titanium acetabular cups with internal CoCr liners. Femoral components were titanium with modular necks. At average 2.1. years postoperatively, 12 THAs (15.4%) demonstrated aseptic failure (10 revisions, 2 revision recommended). All revised hips demonstrated capsular necrosis with positive histology reaction for aseptic lymphocytic vasculitis-associated lesions/adverse local tissue reactions. Prosthetic instability following revision surgery was relatively common. Female gender was a strong risk factor for failure, though smaller cups were not. Both monoblock and modular components fared poorly. Corrosion was frequently observed around the proximal and distal end of the modular femoral necks. © 2013 Elsevier Inc.

D'Lima D.D.,Shiley Center for Orthopaedic Research and Education | Patil S.,Shiley Center for Orthopaedic Research and Education | Steklov N.,Shiley Center for Orthopaedic Research and Education | Colwell Jr. C.W.,Shiley Center for Orthopaedic Research and Education
Clinical Orthopaedics and Related Research | Year: 2011

Background: Tibiofemoral forces are important in the design and clinical outcomes of TKA. We developed a tibial tray with force transducers and a telemetry system to directly measure tibiofemoral compressive forces in vivo. Knee forces and kinematics traditionally have been measured under laboratory conditions. Although this approach is useful for quantitative measurements and experimental studies, the extrapolation of results to clinical conditions may not always be valid. Questions/purposes: We therefore developed wearable monitoring equipment and computer algorithms for classifying and identifying unsupervised activities outside the laboratory. Methods: Tibial forces were measured for activities of daily living, athletic and recreational activities, and with orthotics and braces, during 4 years postoperatively. Additional measurements included video motion analysis, EMG, fluoroscopic kinematic analysis, and ground reaction force measurement. In vivo measurements were used to evaluate computer models of the knee. Finite element models were used for contact analysis and for computing knee kinematics from measured knee forces. A third-generation system was developed for continuous monitoring of knee forces and kinematics outside the laboratory using a wearable data acquisition hardware. Results: By using measured knee forces and knee flexion angle, we were able to compute femorotibial AP translation (-12 to +4 mm), mediolateral translation (-1 to 1.5 mm), axial rotation (-3° to 12°), and adduction-abduction (-1° to +1°). The neural-network-based classification system was able to identify walking, stair-climbing, sit-to-stand, and stand-to-sit activities with 100% accuracy. Conclusions: Our data may be used to improve existing in vitro models and wear simulators, and enhance prosthetic designs and biomaterials. © 2011 The Association of Bone and Joint Surgeons.

Gokhin D.S.,Scripps Research Institute | Kim N.E.,Scripps Research Institute | Lewis S.A.,Scripps Research Institute | Hoenecke H.R.,Shiley Center for Orthopaedic Research and Education | And 2 more authors.
American Journal of Physiology - Cell Physiology | Year: 2012

Force production in skeletal muscle is proportional to the amount of overlap between the thin and thick filaments, which, in turn, depends on their lengths. Both thin-and thick-filament lengths are precisely regulated and uniform within a myofibril. While thick-filament lengths are essentially constant across muscles and species (~1.65 μm), thin-filament lengths are highly variable both across species and across muscles of a single species. Here, we used a high-resolution immunofluorescence and image analysis technique (distributed deconvolution) to directly test the hypothesis that thin-filament lengths vary across human muscles. Using deltoid and pectoralis major muscle biopsies, we identified thin-filament lengths that ranged from 1.19 ± 0.08 to 1.37 ± 0.04 μm, based on tropomodulin localization with respect to the Z-line. Tropomodulin localized from 0.28 to 0.47 μm further from the Z-line than the NH 2-terminus of nebulin in the various biopsies, indicating that human thin filaments have nebulinfree, pointed-end extensions that comprise up to 34% of total thinfilament length. Furthermore, thin-filament length was negatively correlated with the percentage of type 2X myosin heavy chain within the biopsy and shorter in type 2X myosin heavy chain-positive fibers, establishing the existence of a relationship between thin-filament lengths and fiber types in human muscle. Together, these data challenge the widely held assumption that human thin-filament lengths are constant. Our results also have broad relevance to musculoskeletal modeling, surgical reattachment of muscles, and orthopedic rehabilitation. © 2012 the American Physiological Society.

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