Louis Edwin DeFrate

Research Themes

Biomechanics & Mechanobiology, Biomedical Imaging & Biophotonics

Education

• Sc.D. Massachusetts Institute of Technology, 2005

Positions

• Laszlo Ormandy Distinguished Professor of Orthopaedic Surgery
• Professor in Orthopaedic Surgery
• Professor in the Department of Biomedical Engineering
• Affiliate of the Duke Regeneration Center

Awards, Honors, and Distinctions

• Kappa Delta Young Investigator Award. American Academy of Orthopaedic Surgeons and the Orthopaedic Research Society. 2016

Courses Taught

• EGR 393: Research Projects in Engineering
• BME 792: Continuation of Graduate Independent Study
• BME 791: Graduate Independent Study
• BME 789: Internship in Biomedical Engineering
• BME 493: Projects in Biomedical Engineering (GE)

Publications

• Foody JN, Li GK, Bradley PX, Kuehn SJ, Spritzer CE, Kosinski AS, et al. A comparison of three methods for establishing an ACL reference length in vivo. J Biomech. 2024 Sep 21;176:112337.
• Zhao Q, Holt A, Spritzer CE, DeFrate LE, McNulty AL, Wang N. High angular resolution diffusion imaging (HARDI) of porcine menisci: a comparison of diffusion tensor imaging and generalized q-sampling imaging. Quant Imaging Med Surg. 2024 Apr 3;14(4):2738–46.
• Heckelman LN, Kratzer AL, Spritzer CE, Soher BJ, Lewis BD, DeFrate LE. Influence of running on femoroacetabular joint bone-to-bone distances. J Orthop Res. 2024 Apr;42(4):837–42.
• Coppock JA, Zimmer NE, Spritzer CE, Goode AP, DeFrate LE. Automated segmentation and prediction of intervertebral disc morphology and uniaxial deformations from MRI. Osteoarthr Cartil Open. 2023 Sep;5(3):100378.
• Coppock JA, McNulty AL, Porter Starr KN, Holt AG, Borack MS, Kosinski AS, et al. The effects of a 6-month weight loss intervention on physical function and serum biomarkers in older adults with and without osteoarthritis. Osteoarthr Cartil Open. 2023 Sep;5(3):100376.
• Kim-Wang SY, Spritzer CE, Owusu-Akyaw K, Coppock JA, Goode AP, Englander ZA, et al. The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI: Response. Am J Sports Med. 2023 Jul;51(8):NP22–4.
• Kim-Wang SY, Bradley PX, Cutcliffe HC, Collins AT, Crook BS, Paranjape CS, et al. Auto-segmentation of the tibia and femur from knee MR images via deep learning and its application to cartilage strain and recovery. J Biomech. 2023 Mar;149:111473.
• Foody JN, Bradley PX, Spritzer CE, Wittstein JR, DeFrate LE, Englander ZA. Elevated In Vivo ACL Strain Is Associated With a Straight Knee in Both the Sagittal and the Coronal Planes. Am J Sports Med. 2023 Feb;51(2):422–8.
• Bradley PX, Thomas KN, Kratzer AL, Robinson AC, Wittstein JR, DeFrate LE, et al. The Interplay of Biomechanical and Biological Changes Following Meniscus Injury. Curr Rheumatol Rep. 2023 Feb;25(2):35–46.
• Coppock JA, Zimmer NE, Englander ZA, Danyluk ST, Kosinski AS, Spritzer CE, et al. In vivo intervertebral disc mechanical deformation following a treadmill walking "stress test" is inversely related to T1rho relaxation time. Osteoarthritis and cartilage. 2023 Jan;31(1):126–33.
• Kim-Wang SY, Spritzer CE, Owusu-Akyaw K, Coppock JA, Goode AP, Englander ZA, et al. The Predicted Position of the Knee Near the Time of ACL Rupture Is Similar Between 2 Commonly Observed Patterns of Bone Bruising on MRI. Am J Sports Med. 2023 Jan;51(1):58–65.
• Goode AP, Cleveland RJ, George SZ, Schwartz TA, Kraus VB, Renner JB, et al. Predictors of Lumbar Spine Degeneration and Low Back Pain in the Community: The Johnston County Osteoarthritis Project. Arthritis Care Res (Hoboken). 2022 Oct;74(10):1659–66.
• Englander ZA, Foody JN, Cutcliffe HC, Wittstein JR, Spritzer CE, DeFrate LE. Use of a Novel Multimodal Imaging Technique to Model In Vivo Quadriceps Force and ACL Strain During Dynamic Activity. Am J Sports Med. 2022 Aug;50(10):2688–97.
• Martin JT, Wesorick B, Oldweiler AB, Kosinski AS, Goode AP, DeFrate LE. In vivo fluid transport in human intervertebral discs varies by spinal level and disc region. JOR Spine. 2022 Jun;5(2):e1199.
• Heckelman LN, Soher BJ, Spritzer CE, Lewis BD, DeFrate LE. Design and validation of a semi-automatic bone segmentation algorithm from MRI to improve research efficiency. Sci Rep. 2022 May 12;12(1):7825.
• Martin JT, Oldweiler AB, Kosinski AS, Spritzer CE, Soher BJ, Erickson MM, et al. Lumbar intervertebral disc diurnal deformations and T2 and T1rho relaxation times vary by spinal level and disc region. Eur Spine J. 2022 Mar;31(3):746–54.
• Tamayo KS, Heckelman LN, Spritzer CE, DeFrate LE, Collins AT. Obesity impacts the mechanical response and biochemical composition of patellofemoral cartilage: An in vivo, MRI-based investigation. J Biomech. 2022 Mar;134:110991.
• Cutcliffe HC, Kottamasu PK, McNulty AL, Goode AP, Spritzer CE, DeFrate LE. Mechanical metrics may show improved ability to predict osteoarthritis compared to T1rho mapping. J Biomech. 2021 Dec 2;129:110771.
• Heckelman LN, Wesorick BR, DeFrate LE, Lee RH. Diabetes is associated with a lower minimum moment of inertia among older women: An analysis of 3D reconstructions of clinical CT scans. J Biomech. 2021 Nov 9;128:110707.
• Kim-Wang SY, Holt AG, McGowan AM, Danyluk ST, Goode AP, Lau BC, et al. Immune cell profiles in synovial fluid after anterior cruciate ligament and meniscus injuries. Arthritis Res Ther. 2021 Nov 4;23(1):280.
• Andress B, Kim JH, Cutcliffe HC, Amendola A, Goode AP, Varghese S, et al. Meniscus cell regional phenotypes: Dedifferentiation and reversal by biomaterial embedding. J Orthop Res. 2021 Oct;39(10):2177–86.
• Coppock JA, Danyluk ST, Englander ZA, Spritzer CE, Goode AP, DeFrate LE. Increasing BMI increases lumbar intervertebral disc deformation following a treadmill walking stress test. J Biomech. 2021 May 24;121:110392.
• Englander ZA, Lau BC, Wittstein JR, Goode AP, DeFrate LE. Patellar Tendon Orientation and Strain Are Predictors of ACL Strain In Vivo During a Single-Leg Jump. Orthop J Sports Med. 2021 Mar;9(3):2325967121991054.
• Crook BS, Collins AT, Lad NK, Spritzer CE, Wittstein JR, DeFrate LE. Effect of walking on in vivo tibiofemoral cartilage strain in ACL-deficient versus intact knees. J Biomech. 2021 Feb 12;116:110210.
• Kim-Wang SY, Scribani MB, Whiteside MB, DeFrate LE, Lassiter TE, Wittstein JR. Distribution of Bone Contusion Patterns in Acute Noncontact Anterior Cruciate Ligament-Torn Knees. Am J Sports Med. 2021 Feb;49(2):404–9.
• Collins AT, Hu G, Newman H, Reinsvold MH, Goldsmith MR, Twomey-Kozak JN, et al. Obesity alters the collagen organization and mechanical properties of murine cartilage. Sci Rep. 2021 Jan 15;11(1):1626.
• Cutcliffe HC, DeFrate LE. Four-Point Bending Testing for Mechanical Assessment of Mouse Bone Structural Properties. Methods Mol Biol. 2021;2230:199–215.
• Heckelman LN, Riofrio AD, Vinson EN, Collins AT, Gwynn OR, Utturkar GM, et al. Dose and Recovery Response of Patellofemoral Cartilage Deformations to Running. Orthop J Sports Med. 2020 Dec;8(12):2325967120967512.
• Collins AT, Kulvaranon M, Spritzer CE, McNulty AL, DeFrate LE. The Influence of Obesity and Meniscal Coverage on In Vivo Tibial Cartilage Thickness and Strain. Orthop J Sports Med. 2020 Dec;8(12):2325967120964468.
• Cutcliffe HC, Davis KM, Spritzer CE, DeFrate L. The Characteristic Recovery Time as a Novel, Noninvasive Metric for Assessing In Vivo Cartilage Mechanical Function. Ann Biomed Eng. 2020 Dec;48(12):2901–10.
• Englander ZA, Spritzer CE, DeFrate LE. In vivo attachment site to attachment site length and strain of the ACL and its bundles during the full gait cycle measured by MRI and high-speed biplanar radiography: Response. J Biomech. 2020 Aug 26;109:109918.
• Englander ZA, Wittstein JR, Goode AP, Garrett WE, DeFrate LE. Reconsidering Reciprocal Length Patterns of the Anteromedial and Posterolateral Bundles of the Anterior Cruciate Ligament During In Vivo Gait. Am J Sports Med. 2020 Jul;48(8):1893–9.
• Goode AP, Schwartz TA, Kraus VB, Huebner JL, George SZ, Cleveland RJ, et al. Inflammatory, Structural, and Pain Biochemical Biomarkers May Reflect Radiographic Disc Space Narrowing: The Johnston County Osteoarthritis Project. J Orthop Res. 2020 May;38(5):1027–37.
• Hora M, Pontzer H, Defrate LE, Charles HC, Sladek V, Mcginnis A. Effect of gait and velocity on in-vivo tibial loading in humans. In: AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. WILEY; 2020. p. 124–124.
• Heckelman LN, Smith WAR, Riofrio AD, Vinson EN, Collins AT, Gwynn OR, et al. Quantifying the biochemical state of knee cartilage in response to running using T1rho magnetic resonance imaging. Sci Rep. 2020 Feb 5;10(1):1870.
• Cutcliffe HC, DeFrate LE. Comparison of Cartilage Mechanical Properties Measured During Creep and Recovery. Sci Rep. 2020 Jan 31;10(1):1547.
• Englander ZA, Garrett WE, Spritzer CE, DeFrate LE. In vivo attachment site to attachment site length and strain of the ACL and its bundles during the full gait cycle measured by MRI and high-speed biplanar radiography. J Biomech. 2020 Jan 2;98:109443.
• Englander ZA, Baldwin EL, Smith WAR, Garrett WE, Spritzer CE, DeFrate LE. In Vivo Anterior Cruciate Ligament Deformation During a Single-Legged Jump Measured by Magnetic Resonance Imaging and High-Speed Biplanar Radiography. Am J Sports Med. 2019 Nov;47(13):3166–72.
• Goode A, Cleveland R, Hu D, George S, Kraus VB, Schwartz T, et al. Predictors of Incident and Worsening Lumbar Spine Degeneration: The Johnston County Osteoarthritis Project. In: ARTHRITIS & RHEUMATOLOGY. WILEY; 2019.
• Ruprecht JC, Waanders TD, Rowland CR, Nishimuta JF, Glass KA, Stencel J, et al. Meniscus-Derived Matrix Scaffolds Promote the Integrative Repair of Meniscal Defects. Sci Rep. 2019 Jun 18;9(1):8719.
• Englander ZA, Cutcliffe HC, Utturkar GM, Taylor KA, Spritzer CE, Garrett WE, et al. In vivo assessment of the interaction of patellar tendon tibial shaft angle and anterior cruciate ligament elongation during flexion. J Biomech. 2019 Jun 11;90:123–7.
• DeFrate LE, Kim-Wang SY, Englander ZA, McNulty AL. Osteoarthritis year in review 2018: mechanics. Osteoarthritis Cartilage. 2019 Mar;27(3):392–400.
• Paranjape CS, Cutcliffe HC, Grambow SC, Utturkar GM, Collins AT, Garrett WE, et al. A New Stress Test for Knee Joint Cartilage. Sci Rep. 2019 Feb 19;9(1):2283.
• Taylor KA, Collins AT, Heckelman LN, Kim SY, Utturkar GM, Spritzer CE, et al. Activities of daily living influence tibial cartilage T1rho relaxation times. J Biomech. 2019 Jan 3;82:228–33.
• Englander ZA, Cutcliffe HC, Utturkar GM, Garrett WE, Spritzer CE, DeFrate LE. A Comparison of Knee Abduction Angles Measured by a 3D Anatomic Coordinate System Versus Videographic Analysis: Implications for Anterior Cruciate Ligament Injury. Orthop J Sports Med. 2019 Jan;7(1):2325967118819831.
• Collins AT, Hatcher CC, Kim SY, Ziemian SN, Spritzer CE, Guilak F, et al. Selective Enzymatic Digestion of Proteoglycans and Collagens Alters Cartilage T1rho and T2 Relaxation Times. Ann Biomed Eng. 2019 Jan;47(1):190–201.
• Sutter EG, Liu B, Utturkar GM, Widmyer MR, Spritzer CE, Cutcliffe HC, et al. Effects of Anterior Cruciate Ligament Deficiency on Tibiofemoral Cartilage Thickness and Strains in Response to Hopping. Am J Sports Med. 2019 Jan;47(1):96–103.
• Englander ZA, Martin JT, Ganapathy PK, Garrett WE, DeFrate LE. Automatic registration of MRI-based joint models to high-speed biplanar radiographs for precise quantification of in vivo anterior cruciate ligament deformation during gait. J Biomech. 2018 Nov 16;81:36–44.
• Collins AT, Kulvaranon ML, Cutcliffe HC, Utturkar GM, Smith WAR, Spritzer CE, et al. Obesity alters the in vivo mechanical response and biochemical properties of cartilage as measured by MRI. Arthritis Res Ther. 2018 Oct 17;20(1):232.
• Owusu-Akyaw KA, Kim SY, Spritzer CE, Collins AT, Englander ZA, Utturkar GM, et al. Determination of the Position of the Knee at the Time of an Anterior Cruciate Ligament Rupture for Male Versus Female Patients by an Analysis of Bone Bruises: Response. Am J Sports Med. 2018 Sep;46(11):NP48–51.
• Zhang H, Heckelman LN, Spritzer CE, Owusu-Akyaw KA, Martin JT, Taylor DC, et al. In Vivo Assessment of Exercise-Induced Glenohumeral Cartilage Strain. Orthop J Sports Med. 2018 Jul;6(7):2325967118784518.
• Owusu-Akyaw KA, Kim SY, Spritzer CE, Collins AT, Englander ZA, Utturkar GM, et al. Determination of the Position of the Knee at the Time of an Anterior Cruciate Ligament Rupture for Male Versus Female Patients by an Analysis of Bone Bruises. Am J Sports Med. 2018 Jun;46(7):1559–65.
• Martin JT, Oldweiler AB, Spritzer CE, Soher BJ, Erickson MM, Goode AP, et al. A magnetic resonance imaging framework for quantifying intervertebral disc deformation in vivo: Reliability and application to diurnal variations in lumbar disc shape. J Biomech. 2018 Apr 11;71:291–5.
• Goode A, Kraus VB, Golightly Y, Huebner J, George S, Martin J, et al. Association between n-cadherin, keratin-19 and lumican with disc space narrowing: the Johnston county osteoarthritis project. Osteoarthritis and Cartilage. 2018 Apr;26:S421–S421.
• DeFrate L. YEAR IN REVIEW: MECHANICS. OSTEOARTHRITIS AND CARTILAGE. 2018 Apr 1;26:S9–S9.
• Owusu-Akyaw KA, Heckelman LN, Cutcliffe HC, Sutter EG, Englander ZA, Spritzer CE, et al. A comparison of patellofemoral cartilage morphology and deformation in anterior cruciate ligament deficient versus uninjured knees. J Biomech. 2018 Jan 23;67:78–83.
• Liu B, Lad NK, Collins AT, Ganapathy PK, Utturkar GM, McNulty AL, et al. In Vivo Tibial Cartilage Strains in Regions of Cartilage-to-Cartilage Contact and Cartilage-to-Meniscus Contact in Response to Walking. Am J Sports Med. 2017 Oct;45(12):2817–23.
• DeFrate LE. Effects of ACL graft placement on in vivo knee function and cartilage thickness distributions. J Orthop Res. 2017 Jun;35(6):1160–70.
• Hatcher CC, Collins AT, Kim SY, Michel LC, Mostertz WC, Ziemian SN, et al. Relationship between T1rho magnetic resonance imaging, synovial fluid biomarkers, and the biochemical and biomechanical properties of cartilage. J Biomech. 2017 Apr 11;55:18–26.
• Collins AT, Kulvaranon ML, Utturkar GM, Spritzer CE, Guilak F, Defrate LE. In vivo biochemical and biomechanical properties of cartilage are affected by obesity. Osteoarthritis and Cartilage. 2017 Apr;25:S112–3.
• Liu B, Goode AP, Carter TE, Utturkar GM, Huebner JL, Taylor DC, et al. Matrix metalloproteinase activity and prostaglandin E2 are elevated in the synovial fluid of meniscus tear patients. Connect Tissue Res. 2017;58(3–4):305–16.
• Lad NK, Liu B, Ganapathy PK, Utturkar GM, Sutter EG, Moorman CT, et al. Effect of normal gait on in vivo tibiofemoral cartilage strains. J Biomech. 2016 Sep 6;49(13):2870–6.
• Cher WL, Utturkar GM, Spritzer CE, Nunley JA, DeFrate LE, Collins AT. An analysis of changes in in vivo cartilage thickness of the healthy ankle following dynamic activity. J Biomech. 2016 Sep 6;49(13):3026–30.
• DeFrate LE. Dynamic joint imaging in human OA: altered in vivo cartilage function and early onset OA. Osteoarthritis and Cartilage. 2016 Apr;24:S4–S4.
• Huebner JL, Furman BD, Manson MJ, Kimmerling KA, Olson SA, Guilak F, et al. Acute inflammatory response after severe joint injury potentially involved in the development of post-traumatic arthritis. Osteoarthritis and Cartilage. 2016 Apr;24:S79–80.
• Kim SY, Spritzer CE, Utturkar GM, Toth AP, Garrett WE, DeFrate LE. Knee Kinematics During Noncontact Anterior Cruciate Ligament Injury as Determined From Bone Bruise Location. Am J Sports Med. 2015 Oct;43(10):2515–21.
• Carter TE, Taylor KA, Spritzer CE, Utturkar GM, Taylor DC, Moorman CT, et al. In vivo cartilage strain increases following medial meniscal tear and correlates with synovial fluid matrix metalloproteinase activity. J Biomech. 2015 Jun 1;48(8):1461–8.
• Vovos TJ, Furman BD, Huebner JL, Kimmerling KA, Utturkar GM, DeFrate LE, et al. Joint incongruity and biomarkers of bone metabolism as predictors of post-traumatic arthritis in mice. Osteoarthritis and Cartilage. 2015 Apr;23:A242–3.
• Sutter EG, Widmyer MR, Utturkar GM, Spritzer CE, Garrett WE, DeFrate LE. In vivo measurement of localized tibiofemoral cartilage strains in response to dynamic activity. Am J Sports Med. 2015 Feb;43(2):370–6.
• Okafor EC, Utturkar GM, Widmyer MR, Abebe ES, Collins AT, Taylor DC, et al. The effects of femoral graft placement on cartilage thickness after anterior cruciate ligament reconstruction. J Biomech. 2014 Jan 3;47(1):96–101.
• Widmyer MR, Utturkar GM, Leddy HA, Coleman JL, Spritzer CE, Moorman CT, et al. High body mass index is associated with increased diurnal strains in the articular cartilage of the knee. Arthritis Rheum. 2013 Oct;65(10):2615–22.
• Stolberg-Stolberg JA, Furman BD, Garrigues NW, Lee J, Pisetsky DS, Stearns NA, et al. Effects of cartilage impact with and without fracture on chondrocyte viability and the release of inflammatory markers. J Orthop Res. 2013 Aug;31(8):1283–92.
• Taylor KA, Cutcliffe HC, Queen RM, Utturkar GM, Spritzer CE, Garrett WE, et al. In vivo measurement of ACL length and relative strain during walking. J Biomech. 2013 Feb 1;46(3):478–83.
• Coleman JL, Widmyer MR, Leddy HA, Utturkar GM, Spritzer CE, Moorman CT, et al. Diurnal variations in articular cartilage thickness and strain in the human knee. J Biomech. 2013 Feb 1;46(3):541–7.
• Utturkar GM, Irribarra LA, Taylor KA, Spritzer CE, Taylor DC, Garrett WE, et al. The effects of a valgus collapse knee position on in vivo ACL elongation. Ann Biomed Eng. 2013 Jan;41(1):123–30.
• Wilusz RE, DeFrate LE, Guilak F. Immunofluorescence-guided atomic force microscopy to measure the micromechanical properties of the pericellular matrix of porcine articular cartilage. J R Soc Interface. 2012 Nov 7;9(76):2997–3007.
• Wainright WB, Spritzer CE, Lee JY, Easley ME, DeOrio JK, Nunley JA, et al. The effect of modified Broström-Gould repair for lateral ankle instability on in vivo tibiotalar kinematics. Am J Sports Med. 2012 Sep;40(9):2099–104.
• Wilusz RE, Defrate LE, Guilak F. A biomechanical role for perlecan in the pericellular matrix of articular cartilage. Matrix Biol. 2012 Jul;31(6):320–7.
• Abebe ES, Kim J-P, Utturkar GM, Taylor DC, Spritzer CE, Moorman CT, et al. The effect of femoral tunnel placement on ACL graft orientation and length during in vivo knee flexion. J Biomech. 2011 Jul 7;44(10):1914–20.
• Lewis JS, Hembree WC, Furman BD, Tippets L, Cattel D, Huebner JL, et al. Acute joint pathology and synovial inflammation is associated with increased intra-articular fracture severity in the mouse knee. Osteoarthritis Cartilage. 2011 Jul;19(7):864–73.
• Backus JD, Furman BD, Swimmer T, Kent CL, McNulty AL, Defrate LE, et al. Cartilage viability and catabolism in the intact porcine knee following transarticular impact loading with and without articular fracture. J Orthop Res. 2011 Apr;29(4):501–10.
• Abebe ES, Utturkar GM, Taylor DC, Spritzer CE, Kim JP, Moorman CT, et al. The effects of femoral graft placement on in vivo knee kinematics after anterior cruciate ligament reconstruction. J Biomech. 2011 Mar 15;44(5):924–9.
• Taylor KA, Terry ME, Utturkar GM, Spritzer CE, Queen RM, Irribarra LA, et al. Measurement of in vivo anterior cruciate ligament strain during dynamic jump landing. J Biomech. 2011 Feb 3;44(3):365–71.
• Bischof JE, Spritzer CE, Caputo AM, Easley ME, DeOrio JK, Nunley JA, et al. In vivo cartilage contact strains in patients with lateral ankle instability. J Biomech. 2010 Sep 17;43(13):2561–6.
• Bischof JE, Defrate LE, Queen RM, Nunley JA. Bilateral jones fractures in two elite soccer players. Foot Ankle Int. 2010 May;31(5):441–7.
• Van de Velde SK, Bingham JT, Hosseini A, Kozanek M, DeFrate LE, Gill TJ, et al. Increased tibiofemoral cartilage contact deformation in patients with anterior cruciate ligament deficiency. Arthritis Rheum. 2009 Dec;60(12):3693–702.
• Caputo AM, Lee JY, Spritzer CE, Easley ME, DeOrio JK, Nunley JA, et al. In vivo kinematics of the tibiotalar joint after lateral ankle instability. Am J Sports Med. 2009 Nov;37(11):2241–8.
• Abebe ES, Moorman CT, Dziedzic TS, Spritzer CE, Cothran RL, Taylor DC, et al. Femoral tunnel placement during anterior cruciate ligament reconstruction: an in vivo imaging analysis comparing transtibial and 2-incision tibial tunnel-independent techniques. Am J Sports Med. 2009 Oct;37(10):1904–11.
• Caputo AM, Lee JY, Spritzer CE, Easley ME, DeOrio JK, Nunley JA, et al. Lateral ankle instability increases anterior translation and internal rotation of the talus during in vivo loading. Foot and Ankle International. 2009 Aug 1;30(8):804.
• Gelalis ID, DeFrate LE, Stafilas KS, Pakos EE, Kang JD, Gilbertson LG. Three-dimensional analysis of cervical spine motion: reliability of a computer assisted magnetic tracking device compared to inclinometer. Eur Spine J. 2009 Feb;18(2):276–81.
• Van de Velde SK, Gill TJ, DeFrate LE, Papannagari R, Li G. The effect of anterior cruciate ligament deficiency and reconstruction on the patellofemoral joint. Am J Sports Med. 2008 Jun;36(6):1150–9.
• Kaseta MK, DeFrate LE, Charnock BL, Sullivan RT, Garrett WE. Reconstruction technique affects femoral tunnel placement in ACL reconstruction. Clin Orthop Relat Res. 2008 Jun;466(6):1467–74.
• Schwarzkopf R, DeFrate LE, Li G, Herndon JH. The quantification of the origin area of the deep forearm musculature on the interosseous ligament. Bull NYU Hosp Jt Dis. 2008;66(1):9–13.
• Li G, Papannagari R, Nha KW, Defrate LE, Gill TJ, Rubash HE. The coupled motion of the femur and patella during in vivo weightbearing knee flexion. J Biomech Eng. 2007 Dec;129(6):937–43.
• Papannagari R, DeFrate LE, Nha KW, Moses JM, Moussa M, Gill TJ, et al. Function of posterior cruciate ligament bundles during in vivo knee flexion. Am J Sports Med. 2007 Sep;35(9):1507–12.
• Defrate LE, Li G. The prediction of stress-relaxation of ligaments and tendons using the quasi-linear viscoelastic model. Biomech Model Mechanobiol. 2007 Jul;6(4):245–51.
• Li G, Papannagari R, DeFrate LE, Yoo JD, Park SE, Gill TJ. The effects of ACL deficiency on mediolateral translation and varus-valgus rotation. Acta Orthop. 2007 Jun;78(3):355–60.
• Jordan SS, DeFrate LE, Nha KW, Papannagari R, Gill TJ, Li G. The in vivo kinematics of the anteromedial and posterolateral bundles of the anterior cruciate ligament during weightbearing knee flexion. Am J Sports Med. 2007 Apr;35(4):547–54.
• Van de Velde SK, DeFrate LE, Gill TJ, Moses JM, Papannagari R, Li G. The effect of anterior cruciate ligament deficiency on the in vivo elongation of the medial and lateral collateral ligaments. Am J Sports Med. 2007 Feb;35(2):294–300.
• Defrate LE, Nha KW, Papannagari R, Moses JM, Gill TJ, Li G. The biomechanical function of the patellar tendon during in-vivo weight-bearing flexion. J Biomech. 2007;40(8):1716–22.
• Papannagari R, Gill TJ, Defrate LE, Moses JM, Petruska AJ, Li G. In vivo kinematics of the knee after anterior cruciate ligament reconstruction: a clinical and functional evaluation. Am J Sports Med. 2006 Dec;34(12):2006–12.
• Li G, Moses JM, Papannagari R, Pathare NP, DeFrate LE, Gill TJ. Anterior cruciate ligament deficiency alters the in vivo motion of the tibiofemoral cartilage contact points in both the anteroposterior and mediolateral directions. J Bone Joint Surg Am. 2006 Aug;88(8):1826–34.
• Defrate LE, Papannagari R, Gill TJ, Moses JM, Pathare NP, Li G. The 6 degrees of freedom kinematics of the knee after anterior cruciate ligament deficiency: an in vivo imaging analysis. Am J Sports Med. 2006 Aug;34(8):1240–6.
• Li G, Papannagari R, DeFrate LE, Yoo JD, Park SE, Gill TJ. Comparison of the ACL and ACL graft forces before and after ACL reconstruction: an in-vitro robotic investigation. Acta Orthop. 2006 Apr;77(2):267–74.
• Park SE, DeFrate LE, Suggs JF, Gill TJ, Rubash HE, Li G. Erratum to "The change in length of the medial and lateral collateral ligaments during in vivo knee flexion". Knee. 2006 Jan;13(1):77–82.
• Defrate LE, van der Ven A, Boyer PJ, Gill TJ, Li G. The measurement of the variation in the surface strains of Achilles tendon grafts using imaging techniques. J Biomech. 2006;39(3):399–405.
• Park SE, DeFrate LE, Suggs JF, Gill TJ, Rubash HE, Li G. Erratum: The change in length of the medial and lateral collateral ligaments during in vivo knee flexion (The Knee (2005) 12 (377-382) DOI: 10.1016/j.knee.2004.12.011). Knee. 2006 Jan 1;13(1):76–82.
• DeFrate LE, Li G. The prediction of the stress-strain behavior of ligaments and tendons. Proceedings of the 2005 Summer Bioengineering Conference. 2005 Dec 1;2005:874–5.
• Li G, DeFrate LE, Suggs JF, Hanson GR, Papannagari R, Rubash HE. The development of an orthogonal fluoroscopic and MR imaging technique for accurately measuring in vivo knee joint kinematics. Proceedings of the 2005 Summer Bioengineering Conference. 2005 Dec 1;2005:972–3.
• DeFrate LE, Van Der Ven A, Boyer PJ, Gill TJ, Li G. The measurement of the variation in the surface strains of achilles tendon grafts using imaging techniques. Proceedings of the 2005 Summer Bioengineering Conference. 2005 Dec 1;2005:695–6.
• Park SE, DeFrate LE, Suggs JF, Gill TJ, Rubash HE, Li G. The change in length of the medial and lateral collateral ligaments during in vivo knee flexion. Knee. 2005 Oct;12(5):377–82.
• Li G, Park SE, DeFrate LE, Schutzer ME, Ji L, Gill TJ, et al. The cartilage thickness distribution in the tibiofemoral joint and its correlation with cartilage-to-cartilage contact. Clin Biomech (Bristol, Avon). 2005 Aug;20(7):736–44.
• Li G, DeFrate LE, Rubash HE, Gill TJ. Erratum: "In vivo kinematics of the ACL during weight-bearing knee flexion" (Journal of Orthopaedic Research (2005) vol. 23 (340-344) 10.1016/j.orthres.2004.08.006). Journal of Orthopaedic Research. 2005 Jul 1;23(4):977.
• Li G, Defrate LE, Rubash HE, Gill TJ. In vivo kinematics of the ACL during weight-bearing knee flexion. J Orthop Res. 2005 Mar;23(2):340–4.
• Yoo JD, Papannagari R, Park SE, DeFrate LE, Gill TJ, Li G. The effect of anterior cruciate ligament reconstruction on knee joint kinematics under simulated muscle loads. Am J Sports Med. 2005 Feb;33(2):240–6.
• Li G, DeFrate LE, Park SE, Gill TJ, Rubash HE. In vivo articular cartilage contact kinematics of the knee: an investigation using dual-orthogonal fluoroscopy and magnetic resonance image-based computer models. Am J Sports Med. 2005 Jan;33(1):102–7.
• DeFrate LE, Gill TJ, Li G. In vivo function of the posterior cruciate ligament during weightbearing knee flexion. Am J Sports Med. 2004 Dec;32(8):1923–8.
• DeFrate LE, Sun H, Gill TJ, Rubash HE, Li G. In vivo tibiofemoral contact analysis using 3D MRI-based knee models. J Biomech. 2004 Oct;37(10):1499–504.
• Park SE, Stamos BD, DeFrate LE, Gill TJ, Li G. The effect of posterior knee capsulotomy on posterior tibial translation during posterior cruciate ligament tibial inlay reconstruction. Am J Sports Med. 2004 Sep;32(6):1514–9.
• Li G, DeFrate LE, Sun H, Gill TJ. In vivo elongation of the anterior cruciate ligament and posterior cruciate ligament during knee flexion. Am J Sports Med. 2004 Sep;32(6):1415–20.
• Li G, DeFrate LE, Zayontz S, Park SE, Gill TJ. The effect of tibiofemoral joint kinematics on patellofemoral contact pressures under simulated muscle loads. J Orthop Res. 2004 Jul;22(4):801–6.
• DeFrate LE, van der Ven A, Gill TJ, Li G. The effect of length on the structural properties of an Achilles tendon graft as used in posterior cruciate ligament reconstruction. Am J Sports Med. 2004 Jun;32(4):993–7.
• Li G, Most E, DeFrate LE, Suggs JF, Gill TJ, Rubash HE. Effect of the posterior cruciate ligament on posterior stability of the knee in high flexion. J Biomech. 2004 May;37(5):779–83.
• Li G, Wuerz TH, DeFrate LE. Feasibility of using orthogonal fluoroscopic images to measure in vivo joint kinematics. J Biomech Eng. 2004 Apr;126(2):314–8.
• Li G, Zayontz S, Most E, DeFrate LE, Suggs JF, Rubash HE. In situ forces of the anterior and posterior cruciate ligaments in high knee flexion: an in vitro investigation. J Orthop Res. 2004 Mar;22(2):293–7.
• DEFRATE L. In vivo tibiofemoral contact analysis using 3D MRI-based Knee model. Journal of Biomechanics. 2004;37(10):1499–504.
• Li G, Zayontz S, DeFrate LE, Most E, Suggs JF, Rubash HE. Kinematics of the knee at high flexion angles: an in vitro investigation. J Orthop Res. 2004 Jan;22(1):90–5.
• Gill TJ, DeFrate LE, Wang C, Carey CT, Zayontz S, Zarins B, et al. The effect of posterior cruciate ligament reconstruction on patellofemoral contact pressures in the knee joint under simulated muscle loads. Am J Sports Med. 2004;32(1):109–15.
• Li G, DeFrate L, Suggs J, Gill T. Determination of optimal graft lengths for posterior cruciate ligament reconstruction--a theoretical analysis. J Biomech Eng. 2003 Apr;125(2):295–9.
• Gill TJ, DeFrate LE, Wang C, Carey CT, Zayontz S, Zarins B, et al. The biomechanical effect of posterior cruciate ligament reconstruction on knee joint function. Kinematic response to simulated muscle loads. Am J Sports Med. 2003;31(4):530–6.
• Li G, Gill TJ, DeFrate LE, Zayontz S, Glatt V, Zarins B. Biomechanical consequences of PCL deficiency in the knee under simulated muscle loads--an in vitro experimental study. J Orthop Res. 2002 Jul;20(4):887–92.
• DeFrate LE, Li G, Zayontz SJ, Herndon JH. A minimally invasive method for the determination of force in the interosseous ligament. Clin Biomech (Bristol, Avon). 2001 Dec;16(10):895–900.
• Sakai JL, Gilbertson LG, DeFrate LE, Donaldson WF, Kang JD, Woo SLY. Virtual reality assisted visual feedback of cervical spine kinematics for improved control of active range-of-motion maneuvers. American Society of Mechanical Engineers, Bioengineering Division (Publication) BED. 1999 Dec 1;43:15–6.
• DeFrate LE, Sakai JL, Gilbertson LG, Moon SH, Nishida K, Donaldson WF, et al. Magnetic tracking/virtual reality based system for comprehensive kinematic assessment of the cervical spine. American Society of Mechanical Engineers, Bioengineering Division (Publication) BED. 1999 Dec 1;42:63–4.
• Sakai JL, Gilbertson LG, Defrate LE, Donaldson WF, Kang JD, Woo SLY. VIRTUAL REALITY ASSISTED VISUAL FEEDBACK OF CERVICAL SPINE KINEMATICS FOR IMPROVED CONTROL OF ACTIVE RANGE-OF-MOTION MANEUVERS. In: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). 1999. p. 15–6.
• DeFrate LE, Doehring TC, Nishida K, Kang JD, Gilbertson LG, Woo SLY. Virtual reality assisted measurement of in-vivo cervical spine kinematics. American Society of Mechanical Engineers, Bioengineering Division (Publication) BED. 1997 Dec 1;36:9–10.
• DeFrate LE, Doehring TC, Gilbertson LG, Donaldson WF, Kang JD, Woo SLY. Axial rotation limits cervical spine flexion-extension range of motion. American Society of Mechanical Engineers, Bioengineering Division (Publication) BED. 1997 Dec 1;35:445–6.
• DeFrate LE, Doehring TC, Nishida K, Kang JD, Gilbertson LG, Woo SLY. VIRTUAL REALITY ASSISTED MEASUREMENT OF IN-VIVO CERVICAL SPINE KINEMATICS. In: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). 1997. p. 9–10.
• DeFrate LE. IN VIVO STRAIN INCREASES FOLLOWING MEDIAL MENISCAL TEAR AND CORRELATES WITH SYNOVIAL FLUID MATRIX METALLOPROTEINASE ACTIVITY. Osteoarthritis and Cartilage.

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