Research
OA Interventions
We are developing biomechanics and pain neuroscience informed interventions for people with knee osteoarthritis.
Read More

Improving Quality and Quantity of Walking in Knee Osteoarthritis (IWALQQ-OA): The goal of this randomized controlled trial was to assess the feasibility of a mindful walking intervention in people with knee osteoarthritis (NCT03064139)
Telehealth Exercise and Mindfulness for Pain in Osteoarthritis (TEMPO): The goal of this randomized controlled trial is to assess the feasibility of a telehealth delivered mindful exercise intervention in people with knee osteoarthritis (NCT pending)
Radiofrequency ablation (RFA): Genicular nerve radiofrequency ablation for chronic knee pain due to knee OA and its effects on gait
PT and opioids after knee replacement: A real-world cohort study of association of Physical Therapy Interventions with Long-term Opioid Use after Total Knee Arthroplasty (Read more here)
PT and opioids in knee osteoarthritis: A real-world cohort study of association of timing of physical therapy interventions after knee osteoarthritis diagnosis and opioid use
OA Biomechanics AI and Technologies
We are developing technologies to assess movement patterns in everyday life of people with knee osteoarthritis.
Read More
Deep learning using wearable-sensor data: Estimation of knee joint kinematics and kinetics from wearable sensors using deep learning
Wearable Sensors in Knee Osteoarthritis: The goal of this clinical trial is to develop wearable sensor technologies for assessment of gait and chair stand function in people with knee osteoarthritis (NCT04243096)
At-home assessment of movement using wearable sensors: Reliability of wearable sensors for assessing gait and chair stand function at home in people with knee osteoarthritis
Assessment of varus thrust using wearable sensors: Quantifying varus thrust in knee osteoarthritis using wearable inertial sensors: A proof of concept
OA Mechanisms
We are examining mechanisms related to disease worsening in people with knee osteoarthritis.
Read More
Neuroimaging of pain and movement: Using functional near-infrared spectroscopy (fNIRS) to study brain function during movement and exercise in people with central pain sensitization due to knee osteoarthritis.
Machine learning using ground reaction force and physical activity data: Association of ground reaction forces during walking and physical activity with cartilage loss over 2-years in people with knee osteoarthritis: a machine learning analysis in the Multicenter Osteoarthritis Study (MOST)
Machine learning using wearable-sensor gait data: Association of wearable-sensor derived gait measures and knee pain: a machine learning analysis in the Multicenter Osteoarthritis Study (MOST)
Association of pain sensitization with gait and physical activity: Studies on association of measures of quantitative sensory testing and measures of gait and physical activity in the large Multicenter Osteoarthritis Study (MOST)
PUBLICATIONS
See list here
PREPRINTS (OPEN ACCESS)
- Costello KE, Felson DT, Jafarzadeh SR, Guermazi A, Roemer FW, Segal NA, Lewis CE, Nevitt MC, Lewis CL, Kolachalama VB, Kumar D. Gait, physical activity, and tibiofemoral cartilage damage: A longitudinal machine learning analysis in the Multicenter Osteoarthritis Study. medRxiv 2022 doi: https://doi.org/10.1101/2022.06.30.22277057
PEER REVIEWED
- Costello KE, Felson DT, Jafarzadeh SR, Guermazi A, Roemer FW, Segal NA, Lewis CE, Nevitt MC, Lewis CL, Kolachalama VB, Kumar D. Gait, physical activity and tibiofemoral cartilage damage: a longitudinal machine learning analysis in the Multicenter Osteoarthritis Study. Br J Sports Med. 2023 Mar 3;. doi: 10.1136/bjsports-2022-106142. [Epub ahead of print] PubMed PMID: 36868795.
- Kumar D, Neogi T, Peloquin C, Marinko L, Camarinos J, Aoyagi K, Felson DT, Dubreuil M. Delayed timing of physical therapy initiation increases the risk of future opioid use in individuals with knee osteoarthritis: a real-world cohort study. Br J Sports Med. 2023 Feb 23;. doi: 10.1136/bjsports-2022-106044. [Epub ahead of print] PubMed PMID: 36822841.
- Rose MJ, Neogi T, Friscia B, Torabian KA, LaValley MP, Gheller M, Adamowicz L, Georgiev P, Viktrup L, Demanuele C, Wacnik PW, Kumar D. Reliability of wearable sensors for assessing gait and chair stand function at home in people with knee osteoarthritis. Arthritis Care Res (Hoboken). 2023 Feb 3;. doi: 10.1002/acr.25096. [Epub ahead of print] PubMed PMID: 36734316.
- Bacon KL, Felson DT, Jafarzadeh SR, Kolachalama VB, Hausdorff JM, Gazit E, Segal NA, Lewis CE, Nevitt MC, Kumar D. Relation of gait measures with mild unilateral knee pain during walking using machine learning. Sci Rep. 2022 Dec 23;12(1):22200. doi: 10.1038/s41598-022-21142-2. PubMed PMID: 36564397; PubMed Central PMCID: PMC9789148.
- Rose MJ, LaValley MP, Jafarzadeh SR, Costello KE, Shah N, Lee S, Borrelli B, Messier SP, Neogi T, Kumar D. Impact of COVID-19 Pandemic on Physical Activity, Pain, Mood, and Sleep in Adults With Knee Osteoarthritis. Journal for the measurement of physical behaviour. 2022 Sep
- Endrighi R, Zhao Y, Hughes RB, Kumar D, Borrelli B.Associations Between Smoking Status and Physical and Mental Health-Related Quality of Life Among Individuals With Mobility Impairments.Ann Behav Med.2022 Aug 30;56(9):890-899. doi: 10.1093/abm/kaab077.PubMed PMID: 34453512; PubMed Central PMCID: PMC9424865.
- Shah N, Kramer J, Borrelli B, Kumar D. Interrelations between factors related to physical activity in inactive adults with knee pain. Disabil Rehabil. 2022 Jul;44(15):3890-3896. doi: 10.1080/09638288.2021.1891303. PubMed PMID: 33689528; PubMed Central PMCID: PMC8426423.
- Shah N, Costello K, Mehta A, Kumar D. Applications of Digital Health Technologies in Knee Osteoarthritis: Narrative Review. JMIR Rehabil Assist Technol. 2022 Jun 8;9(2):e33489. doi: 10.2196/33489. Review. PubMed PMID: 35675102; PubMed Central PMCID: PMC9218886.
- Rose MJ, Costello KE, Eigenbrot S, Torabian K, Kumar D. Inertial Measurement Units and Application for Remote Health Care in Hip and Knee Osteoarthritis: Narrative Review. JMIR Rehabil Assist Technol. 2022 Jun 2;9(2):e33521. doi: 10.2196/33521. Review. PubMed PMID: 35653180; PubMed Central PMCID: PMC9204569.
- Aoyagi K, Liew JW, Farrar JT, Wang N, Carlesso L, Kumar D, Frey Law L, Lewis CE, Nevitt M, Neogi T. Does weight-bearing versus non-weight-bearing pain reflect different pain mechanisms in knee osteoarthritis?: the Multicenter Osteoarthritis Study (MOST). Osteoarthritis Cartilage. 2022 Apr;30(4):545-550. doi: 10.1016/j.joca.2021.10.014. Epub 2021 Nov 19. PubMed PMID: 34801670; PubMed Central PMCID: PMC8940656.
- Aoyagi K, Neogi T, Peloquin C, Dubreuil M, Marinko L, Camarinos J, Felson DT, Kumar D. Association of Physical Therapy Interventions With Long-term Opioid Use After Total Knee Replacement. JAMA Netw Open. 2021 Oct 1;4(10):e2131271. doi: 10.1001/jamanetworkopen.2021.31271. PubMed PMID: 34705013; PubMed Central PMCID: PMC8552057.
- Kumar D, Link TM, Jafarzadeh SR, LaValley MP, Majumdar S, Souza RB. Association of Quadriceps Adiposity With an Increase in Knee Cartilage, Meniscus, or Bone Marrow Lesions Over Three Years. Arthritis Care Res (Hoboken). 2021 Aug;73(8):1134-1139. doi: 10.1002/acr.24232. Epub 2021 Jul 5. PubMed PMID: 32339414; PubMed Central PMCID: PMC7606313.
- Costello KE, Felson DT, Neogi T, Segal NA, Lewis CE, Gross KD, Nevitt MC, Lewis CL, Kumar D. Ground reaction force patterns in knees with and without radiographic osteoarthritis and pain: descriptive analyses of a large cohort (the Multicenter Osteoarthritis Study). Osteoarthritis Cartilage. 2021 Aug;29(8):1138-1146. doi: 10.1016/j.joca.2021.03.009. Epub 2021 Mar 20. PubMed PMID: 33757856; PubMed Central PMCID: PMC8319033.
- Brown C, Marinko L, LaValley MP, Kumar D. Quadriceps Strength After Anterior Cruciate Ligament Reconstruction Compared With Uninjured Matched Controls: A Systematic Review and Meta-analysis. Orthop J Sports Med. 2021 Apr;9(4):2325967121991534. doi: 10.1177/2325967121991534. eCollection 2021 Apr. Review. PubMed PMID: 33889639; PubMed Central PMCID: PMC8040575.
- Costello KE, Eigenbrot S, Geronimo A, Guermazi A, Felson DT, Richards J, Kumar D. Quantifying varus thrust in knee osteoarthritis using wearable inertial sensors: A proof of concept. Clin Biomech (Bristol, Avon). 2020 Dec;80:105232. doi: 10.1016/j.clinbiomech.2020.105232. Epub 2020 Nov 11. PubMed PMID: 33202314; PubMed Central PMCID: PMC7749075
- Espinosa SE, Costello KE, Souza RB, Kumar D. Lower knee extensor and flexor strength is associated with varus thrust in people with knee osteoarthritis. J Biomech. 2020 Jun 23;107:109865. doi: 10.1016/j.jbiomech.2020.109865. Epub 2020 May 30. PubMed PMID: 32517867; PubMed Central PMCID: PMC7322620.
- Porciuncula F, Roto AV, Kumar D, Davis I, Roy S, Walsh CJ, Awad LN. Wearable Movement Sensors for Rehabilitation: A Focused Review of Technological and Clinical Advances. PM R. 2018 Sep;10(9 Suppl 2):S220-S232. doi: 10.1016/j.pmrj.2018.06.013. Review. PubMed PMID: 30269807; PubMed Central PMCID: PMC6700726.
- Kumar D, Wyatt C, Lee S, Okazaki N, Chiba K, Link TM, Souza RB, Majumdar S. Sagittal plane walking patterns are related to MRI changes over 18-months in people with and without mild-moderate hip osteoarthritis. J Orthop Res. 2018 May;36(5):1472-1477. doi: 10.1002/jor.23763. Epub 2017 Nov 2. PubMed PMID: 29044677; PubMed Central PMCID: PMC5906210.
- Kumar D, Su F, Wu D, Pedoia V, Heitkamp L, Ma CB, Souza RB, Li X. Frontal Plane Knee Mechanics and Early Cartilage Degeneration in People With Anterior Cruciate Ligament Reconstruction: A Longitudinal Study. Am J Sports Med. 2018 Feb;46(2):378-387. doi: 10.1177/0363546517739605. Epub 2017 Nov 10. PubMed PMID: 29125920; PubMed Central PMCID: PMC6709529.
- Gallo MC, Wyatt C, Pedoia V, Kumar D, Lee S, Nardo L, Link TM, Souza RB, Majumdar S. T1ρ and T2 relaxation times are associated with progression of hip osteoarthritis. Osteoarthritis Cartilage. 2016 Aug;24(8):1399-407. doi: 10.1016/j.joca.2016.03.005. Epub 2016 Mar 10. PubMed PMID: 26973330; PubMed Central PMCID: PMC4955678.
- Calixto NE, Kumar D, Subburaj K, Singh J, Schooler J, Nardo L, Li X, Souza RB, Link TM, Majumdar S. Zonal differences in meniscus MR relaxation times in response to in vivo static loading in knee osteoarthritis. J Orthop Res. 2016 Feb;34(2):249-61. doi: 10.1002/jor.23004. Epub 2015 Aug 12. PubMed PMID: 26223430; PubMed Central PMCID: PMC6714045.
- Li X, Pedoia V, Kumar D, Rivoire J, Wyatt C, Lansdown D, Amano K, Okazaki N, Savic D, Koff MF, Felmlee J, Williams SL, Majumdar S. Cartilage T1ρ and T2 relaxation times: longitudinal reproducibility and variations using different coils, MR systems and sites. Osteoarthritis Cartilage. 2015 Dec;23(12):2214-2223. doi: 10.1016/j.joca.2015.07.006. Epub 2015 Jul 15. PubMed PMID: 26187574; PubMed Central PMCID: PMC4663102.
- Samaan MA, Teng HL, Kumar D, Lee S, Link TM, Majumdar S, Souza RB. Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait. Clin Biomech (Bristol, Avon). 2015 Dec;30(10):1202-9. doi: 10.1016/j.clinbiomech.2015.08.003. Epub 2015 Aug 11. PubMed PMID: 26298706; PubMed Central PMCID: PMC4674371.
- McDermott K, Kumar D, Goldman V, Feng H, Mehling W, Moskowitz JT, Souza RB, Hecht FM. Training in ChiRunning to reduce blood pressure: a randomized controlled pilot study. BMC Complement Altern Med. 2015 Oct 15;15:368. doi: 10.1186/s12906-015-0895-x. PubMed PMID: 26471194; PubMed Central PMCID: PMC4608185.
- Kumar D, Souza RB, Subburaj K, MacLeod TD, Singh J, Calixto NE, Nardo L, Link TM, Li X, Lane NE, Majumdar S. Are There Sex Differences in Knee Cartilage Composition and Walking Mechanics in Healthy and Osteoarthritis Populations?. Clin Orthop Relat Res. 2015 Aug;473(8):2548-58. doi: 10.1007/s11999-015-4212-2. PubMed PMID: 25716211; PubMed Central PMCID: PMC4488198.
- Kumar D, McDermott K, Feng H, Goldman V, Luke A, Souza RB, Hecht FM. Effects of Form-Focused Training on Running Biomechanics: A Pilot Randomized Trial in Untrained Individuals. PM R. 2015 Aug;7(8):814-822. doi: 10.1016/j.pmrj.2015.01.010. Epub 2015 Jan 26. PubMed PMID: 25633634; PubMed Central PMCID: PMC4515408.
- Wyatt C, Kumar D, Subburaj K, Lee S, Nardo L, Narayanan D, Lansdown D, Vail T, Link TM, Souza RB, Majumdar S. Cartilage T1ρ and T2 Relaxation Times in Patients With Mild-to-Moderate Radiographic Hip Osteoarthritis. Arthritis Rheumatol. 2015 Jun;67(6):1548-56. doi: 10.1002/art.39074. PubMed PMID: 25779656; PubMed Central PMCID: PMC6348065.
- Lee S, Nardo L, Kumar D, Wyatt CR, Souza RB, Lynch J, McCulloch CE, Majumdar S, Lane NE, Link TM. Scoring hip osteoarthritis with MRI (SHOMRI): A whole joint osteoarthritis evaluation system. J Magn Reson Imaging. 2015 Jun;41(6):1549-57. doi: 10.1002/jmri.24722. Epub 2014 Aug 20. PubMed PMID: 25139720; PubMed Central PMCID: PMC4336224.
- Teng HL, MacLeod TD, Kumar D, Link TM, Majumdar S, Souza RB. Individuals with isolated patellofemoral joint osteoarthritis exhibit higher mechanical loading at the knee during the second half of the stance phase. Clin Biomech (Bristol, Avon). 2015 May;30(4):383-90. doi: 10.1016/j.clinbiomech.2015.02.008. Epub 2015 Feb 17. PubMed PMID: 25726158; PubMed Central PMCID: PMC4404202.
- Kumar D, Wyatt C, Chiba K, Lee S, Nardo L, Link TM, Majumdar S, Souza RB. Anatomic correlates of reduced hip extension during walking in individuals with mild-moderate radiographic hip osteoarthritis. J Orthop Res. 2015 Apr;33(4):527-34. doi: 10.1002/jor.22781. Epub 2015 Feb 12. PubMed PMID: 25678302; PubMed Central PMCID: PMC4376613.
- Pun S, Kumar D, Lane NE. Femoroacetabular impingement. Arthritis Rheumatol. 2015 Jan;67(1):17-27. doi: 10.1002/art.38887. Review. PubMed PMID: 25308887; PubMed Central PMCID: PMC4280287.
- MacLeod TD, Subburaj K, Wu S, Kumar D, Wyatt C, Souza RB. Magnetic resonance analysis of loaded meniscus deformation: a novel technique comparing participants with and without radiographic knee osteoarthritis. Skeletal Radiol. 2015 Jan;44(1):125-35. doi: 10.1007/s00256-014-2022-3. Epub 2014 Oct 10. PubMed PMID: 25296900; PubMed Central PMCID: PMC4256123.
- Kumar D, Souza RB, Singh J, Calixto NE, Nardo L, Link TM, Li X, Majumdar S. Physical activity and spatial differences in medial knee T1rho and t2 relaxation times in knee osteoarthritis. J Orthop Sports Phys Ther. 2014 Dec;44(12):964-72. doi: 10.2519/jospt.2014.5523. Epub 2014 Oct 29. PubMed PMID: 25353261; PubMed Central PMCID: PMC4476033.
- Kumar D, Kothari A, Souza RB, Wu S, Benjamin Ma C, Li X. Frontal plane knee mechanics and medial cartilage MR relaxation times in individuals with ACL reconstruction: A pilot study. Knee. 2014 Oct;21(5):881-5. doi: 10.1016/j.knee.2014.06.005. Epub 2014 Jun 20. PubMed PMID: 24993277; PubMed Central PMCID: PMC4175149.
- Souza RB, Kumar D, Calixto N, Singh J, Schooler J, Subburaj K, Li X, Link TM, Majumdar S. Response of knee cartilage T1rho and T2 relaxation times to in vivo mechanical loading in individuals with and without knee osteoarthritis. Osteoarthritis Cartilage. 2014 Oct;22(10):1367-76. doi: 10.1016/j.joca.2014.04.017. Epub 2014 Apr 30. PubMed PMID: 24792208; PubMed Central PMCID: PMC4184934.
- Kumar D, Dillon A, Nardo L, Link TM, Majumdar S, Souza RB. Differences in the association of hip cartilage lesions and cam-type femoroacetabular impingement with movement patterns: a preliminary study. PM R. 2014 Aug;6(8):681-9. doi: 10.1016/j.pmrj.2014.02.002. Epub 2014 Feb 14. PubMed PMID: 24534097; PubMed Central PMCID: PMC4133316.
- Kumar D, Karampinos DC, MacLeod TD, Lin W, Nardo L, Li X, Link TM, Majumdar S, Souza RB. Quadriceps intramuscular fat fraction rather than muscle size is associated with knee osteoarthritis. Osteoarthritis Cartilage. 2014 Feb;22(2):226-34. doi: 10.1016/j.joca.2013.12.005. Epub 2013 Dec 20. PubMed PMID: 24361743; PubMed Central PMCID: PMC3932784.
- Schooler J, Kumar D, Nardo L, McCulloch C, Li X, Link TM, Majumdar S. Longitudinal evaluation of T1ρ and T2 spatial distribution in osteoarthritic and healthy medial knee cartilage. Osteoarthritis Cartilage. 2014 Jan;22(1):51-62. doi: 10.1016/j.joca.2013.10.014. Epub 2013 Nov 2. PubMed PMID: 24188868; PubMed Central PMCID: PMC3934359.
- Kumar D, Swanik CB, Reisman DS, Rudolph KS. Individuals with medial knee osteoarthritis show neuromuscular adaptation when perturbed during walking despite functional and structural impairments. J Appl Physiol (1985). 2014 Jan 1;116(1):13-23. doi: 10.1152/japplphysiol.00244.2013. Epub 2013 Sep 26. PubMed PMID: 24072409; PubMed Central PMCID: PMC3921367.
- Kumar D, Subburaj K, Lin W, Karampinos DC, McCulloch CE, Li X, Link TM, Souza RB, Majumdar S. Quadriceps and hamstrings morphology is related to walking mechanics and knee cartilage MRI relaxation times in young adults. J Orthop Sports Phys Ther. 2013 Dec;43(12):881-90. doi: 10.2519/jospt.2013.4486. Epub 2013 Oct 30. PubMed PMID: 24175607; PubMed Central PMCID: PMC4476495.
- Kumar D, Wyatt CR, Lee S, Nardo L, Link TM, Majumdar S, Souza RB. Association of cartilage defects, and other MRI findings with pain and function in individuals with mild-moderate radiographic hip osteoarthritis and controls. Osteoarthritis Cartilage. 2013 Nov;21(11):1685-92. doi: 10.1016/j.joca.2013.08.009. Epub 2013 Aug 12. PubMed PMID: 23948977; PubMed Central PMCID: PMC3804140.
- Valentinitsch A, Karampinos DC, Alizai H, Subburaj K, Kumar D, Link TM, Majumdar S. Automated unsupervised multi-parametric classification of adipose tissue depots in skeletal muscle. J Magn Reson Imaging. 2013 Apr;37(4):917-27. doi: 10.1002/jmri.23884. Epub 2012 Oct 23. PubMed PMID: 23097409; PubMed Central PMCID: PMC3573225.
- Kumar D, Manal KT, Rudolph KS. Knee joint loading during gait in healthy controls and individuals with knee osteoarthritis. Osteoarthritis Cartilage. 2013 Feb;21(2):298-305. doi: 10.1016/j.joca.2012.11.008. Epub 2012 Nov 24. PubMed PMID: 23182814; PubMed Central PMCID: PMC3804122.
- Kumar D, Schooler J, Zuo J, McCulloch CE, Nardo L, Link TM, Li X, Majumdar S. Trabecular bone structure and spatial differences in articular cartilage MR relaxation times in individuals with posterior horn medial meniscal tears. Osteoarthritis Cartilage. 2013 Jan;21(1):86-93. doi: 10.1016/j.joca.2012.09.014. Epub 2012 Oct 6. PubMed PMID: 23047010; PubMed Central PMCID: PMC3538917.
- Subburaj K, Kumar D, Souza RB, Alizai H, Li X, Link TM, Majumdar S. The acute effect of running on knee articular cartilage and meniscus magnetic resonance relaxation times in young healthy adults. Am J Sports Med. 2012 Sep;40(9):2134-41. doi: 10.1177/0363546512449816. Epub 2012 Jun 22. PubMed PMID: 22729505; PubMed Central PMCID: PMC3660554.
- Kumar D, Rudolph KS, Manal KT. EMG-driven modeling approach to muscle force and joint load estimations: case study in knee osteoarthritis. J Orthop Res. 2012 Mar;30(3):377-83. doi: 10.1002/jor.21544. Epub 2011 Sep 7. PubMed PMID: 21901754; PubMed Central PMCID: PMC3250571.
- Shin CS, Souza RB, Kumar D, Link TM, Wyman BT, Majumdar S. In vivo tibiofemoral cartilage-to-cartilage contact area of females with medial osteoarthritis under acute loading using MRI. J Magn Reson Imaging. 2011 Dec;34(6):1405-13. doi: 10.1002/jmri.22796. Epub 2011 Sep 23. PubMed PMID: 21953771.
- Maheshwari AV, Malhotra R, Kumar D, Pitcher JD Jr. Rupture of the ilio-psoas tendon after a total hip arthroplasty: an unusual cause of radio-lucency of the lesser trochanter simulating a malignancy. J Orthop Surg Res. 2010 Feb 5;5:6. doi: 10.1186/1749-799X-5-6. PubMed PMID: 20205863; PubMed Central PMCID: PMC2826299.
- Maheshwari AV, Kounine MM, Soaita M, Kumar D, Pitcher JD Jr. Osteoporotic insufficiency fractures of the pelvis simulating a malignancy in an elderly man. Am J Orthop (Belle Mead NJ). 2009 Feb;38(2):E45-8. PubMed PMID: 19340388.
- Aggarwal SR, Kumar D. Lower extremity muscle strength and balance performance in Indian Community dwelling elderly men aged 50 years and above. Indian Journal of Physiotherapy and Occupational Therapy. 2006 January; 1(1):13-23.