Sports Medicine Research

At Stanford, we understand that athletics are a vital part of life for adolescents. The development of physical motor skills, and the teamwork and communication tools acquired through sports and physical activity are important for well rounded adolescent growth and development. Through expert patient care- from your child’s clinical visits and surgical experience, to the physical therapy and return to play preparation- our goal is to provide your child with the best tools for a successful and timely return to their athletic endeavors. Our pediatric sports research team studies the best surgical treatments, care pathways, and rehabilitation programs to get your child back to 100% in the most efficient way possible.

Kevin Shea
Division Chief Pediatric Orthopaedics, Stanford University (2026 - Present) Vice Chief of Pediatric Orthopaedic Surgery for Research, Stanford University (2018 - Present) Director of Pediatric Sports Medicine, Stanford University (2018 - Present) Assistant Surgeon-in-Chief for Quality and Supply Chain Management, LPCH, Stanford Children's Hospital (2018 - Present)

Publications

  • Evaluating ChatGPT's Ability to Answer Common Parent Questions on Avascular Necrosis in Children HSS JOURNAL Smith, G. B., Hofmann, G. H., Gussner, A. V., Duru, N. O., Laureano, T. A., Meadows, M. C., Chan, C., Shea, K. G. 2026

    View details for DOI 10.1177/15563316251408833

    View details for Web of Science ID 001666179200001

  • Evaluating ChatGPT's Ability to Answer Common Parent Questions on Avascular Necrosis in Children. HSS journal : the musculoskeletal journal of Hospital for Special Surgery Smith, G. B., Hofmann, G. H., Gussner, A. V., Duru, N. O., Laureano, T. A., Meadows, M. C., Chan, C., Shea, K. G. 2026: 15563316251408833

    Abstract

    Avascular necrosis (AVN) of the bone may result in severe pain, and patients with AVN and their families may seek out information about the condition. With the rise of ChatGPT, AVN patients and families may turn to this chatbot with questions.We sought to explore expert clinicians' perceptions of the quality of ChatGPT's responses to frequently asked parent questions about AVN in children. Secondary aims of this study were to assess provider perceptions of ChatGPT and AVN parental education and to evaluate the readability of ChatGPT responses.We conducted a cross-sectional survey study of 9 pediatric orthopedic surgeons, oncologists, and advanced practice providers with expertise in the clinical management of AVN. Fifteen common questions parents ask about AVN were posed to ChatGPT, preceded by the following prompt: "Please answer the following parent question relating to avascular necrosis. Please give me a response at or below a sixth-grade reading level: [Question]." The answers were evaluated by participants using a 4-point Likert scale. ChatGPT responses were also assessed using the following readability scores: Flesch-Kincaid Grade Level, Gunning Fog index, and Flesch Reading Ease. In addition, the survey included 4 questions developed to gather overall provider perceptions.Providers deemed answers to all 15 questions as at least satisfactory, requiring minimal clarification on average. Yet only 3 ChatGPT responses (20%) were at or below a sixth-grade reading level, as prompted. The average Flesch-Kincaid Grade Level was 6.94, and the average Gunning Fog Index was 9.22, suggesting the responses reflect a reading level between approximately seventh grade and early high school. A majority of providers agreed that these responses would be sufficient for most parents (56%) and that the information was at the appropriate reading level (100%).The findings of this small survey study suggest that ChatGPT's responses to common parent questions about AVN were satisfactory, requiring minimal clarification. ChatGPT has the potential to serve as a resource for orthopedic patients and family education, though concerns remain.

    View details for DOI 10.1177/15563316251408833

    View details for PubMedID 41585448

    View details for PubMedCentralID PMC12823359

  • Associations between age and mechanical properties in skeletally immature human patellar tendons. Journal of the mechanical behavior of biomedical materials Mattar, L. T., Höger, S. A., Wackerle, A. M., Baggett, J. J., Runer, A., Shea, K. G., Musahl, V., Debski, R. E. 2026; 176: 107341

    Abstract

    The objective was to quantify the mechanical properties of the central region of skeletally immature human patellar tendons and the associations with age. Twenty-six patella-patellar tendon complexes were examined (range 0.1-9.9 years, 17 males, 9 females). The cross-sectional area at the midsubstance of the native and dog-boned patellar tendons were measured using a 3D laser scanning system. The patellar tendons underwent a mechanical testing protocol to failure with loading criteria normalized to cross-sectional area. Associations between mechanical properties, native cross-sectional area, and age were determined using Pearson or Spearman's correlations. The only association observed between age and mechanical properties was a positive association between age and ultimate stress (R2 = 0.21, p = 0.02), thus as age increased, the ultimate stress increased. No association between age and modulus was found (p > 0.05). A positive association between age and native cross-sectional area was observed (R2 = 0.64, p = 0.001). Furthermore, 46 % of specimens lacked a typical toe region of the stress-strain curve. Increased ultimate stress with age may indicate the patellar tendon adapts throughout maturation to increase the force per unit area withstood before failing. In combination with the increases in native cross-sectional area, the patellar tendon may adapt to increased loading occurring at the knee throughout maturation at the macrostructural and microstructural levels. The lack of a toe region in some patellar tendons may indicate additional differences in tissue architecture such as smaller collagen crimp angles, more collagen cross-linking, or lower elastin concentrations. Thus, the current study provides information on changes in tissue function throughout growth and development.

    View details for DOI 10.1016/j.jmbbm.2026.107341

    View details for PubMedID 41520581

  • Higher arterial supply in the distal quadriceps tendon: Results from 7-Tesla quantitative magnetic resonance imaging, histology and high-resolution computed tomography. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA Mueller, M. M., Klinger, C. E., Conner-Rilk, S., Wang, J., Shea, K. G., DiFelice, G. S., Brown, R., Bilal, M., Potter, H. G., Helfet, D. L., Rodeo, S. A., Green, D. W. 2025

    Abstract

    PURPOSE: This study aimed to quantitatively assess relative arterial contributions to the quadriceps tendon (QT) using 7-Tesla quantitative magnetic resonance imaging (7T-qMRI), histology and high-resolution computed tomography (micro-CT) in a fresh-frozen human cadaveric model.METHODS: Six human cadaveric knee pairs were obtained (mean age: 43 years; range: 23-61 years). Pre- and post-contrast 7T-qMRI scans were performed to quantify tendonous vascularity. Subsequent algorithm-based quantitative histologic analysis was performed using hematoxylin and eosin staining, with validation by CD31 immunohistochemistry. Qualitative analysis was performed on two additional knee specimens using 98mum micro-CT imaging.RESULTS: The distal QT demonstrated higher median arterial contributions versus central and proximal regions (distal, 47.4% [interquartile range: 30.8%-64.1%]; central, 28.6% [20.4%-41.5%]; proximal, 11.6% [8.7%-18.4%]), with significantly greater contributions distally versus proximally (Cohen's d=1.58; p=0.021). These findings aligned with the sagittal sub-analysis (deep-proximal 17.2±19.3% vs. deep-distal 43.4±20.3%; Cohen's d=1.32; p=0.050). Histologic analysis (interobserver-reliability: r=0.95) corroborated the MRI results (distal QT, 43.5±7.9%; central, 30.7±6.4%; proximal, 25.8±4.1%), with significant differences between distal and both proximal (Cohen's d=2.81; p<0.001) and central (Cohen's d=1.78; p=0.012) regions. The deep layer was found to have significantly higher arterial contributions (61.6±14.2%) versus the superficial layer (38.4±14.2%) (Cohen's d=1.64; p=0.018). The medial and lateral QT demonstrated lower arterial contributions versus middle QT (Cohen's d=0.96-1.26; p>0.050).CONCLUSION: 7T-qMRI and algorithm-based histological analysis of arterial QT contributions revealed significantly greater arterial contributions in the distal compared to the proximal as well as in the deep compared to the superficial region. While the central region demonstrated higher arterial contributions than the medial and lateral aspects, these differences were not statistically significant. Given that the majority of injuries affect the distal and central portions of the QT, these findings reinforce the rationale for direct tendon-to-bone repair; however, clinical studies are necessary to confirm these findings.LEVEL OF EVIDENCE: Level V, cadaveric study.

    View details for DOI 10.1002/ksa.70253

    View details for PubMedID 41451648

  • 3D Patellar instability Anatomical Severity Score (3D-PASS): A Novel Machine Learning Score Using 3D Bone Position From MRI to Predict Outcomes of Patellar Instability Treatment (Using a Subset of Data in the JUPITER Cohort). Orthopaedic journal of sports medicine Sinopoli, M. L., Gatti, A. A., Wright, C. E., Bartsch, A., Veerkamp, M. W., Boutin, R. D., Mintz, D. N., Emery, K. H., Shea, K. G., Chaudhari, A. S., JUPITER Study Group, Wall, E. J., Elangovan, S., Green, D. W., Fabricant, P. D., Strickland, S. M., Shubin Stein, B. E., Parikh, S. N., Delp, S. L., Sherman, S. L. 2025; 13 (12): 23259671251362675

    Abstract

    Background: Patellar instability treatment outcomes vary. Early prediction of patient responses to treatment is needed to personalize interventions, reduce recurrent instability, and improve outcomes. Existing scores that predict outcomes rely on 2-dimensional (2D) imaging measures that do not fully capture 3-dimensional (3D) anatomical data.Purpose/Hypothesis: We aimed to develop a 3D medical imaging-based anatomical score of patellar instability severity. It was hypothesized that our 3D score would demonstrate stronger associations with instability history and posttreatment patient-reported outcomes (PROs) than a 2D imaging score.Study Design: Cohort study (diagnosis); Level of evidence, 2.Methods: Pretreatment magnetic resonance images from 26 control patients and 244 patients with first-time and recurrent patellar instability were retrospectively analyzed from 2 sites associated with the prospective JUPITER (Justifying Patellar Instability Treatment by Results) study group. Using statistically derived 3D features that reflect relative bone positions and bone shape, as well as 2D imaging measures, we developed several preliminary anatomical severity scores. We tested these scores based on the ability to distinguish first-time from recurrent instability patients. Then, we assessed correlations between these scores and baseline and 1-year posttreatment PROs, using the Kujala Anterior Knee Pain Scale (Kujala) and Banff Patellar Instability Instrument 2.0 (BPII 2.0). A final score-the 3D Patellar instability Anatomical Severity Score (3D-PASS)-was created to best correlate with PROs.Results: 3D-PASS, based on patellar and tibial positions relative to the femur, distinguished first-time from recurrent instability patients (P = .002) and correlated with 1-year outcomes (r nonop Kujala = -0.70; r nonop BPII 2.0 = -0.68, r op Kujala = -0.23; r op BPII 2.0 = -0.25). 3D relative bone positions were more informative than 2D imaging measures and 3D bone shape, neither of which correlated with outcomes.Conclusion: A higher 3D-PASS is associated with instability history and worse outcomes across all patients (first-time and recurrent) treated nonoperatively or operatively. While 3D relative bone positions correlated with outcomes, 3D bone shapes did not.

    View details for DOI 10.1177/23259671251362675

    View details for PubMedID 41479879

  • Meniscal Repair in the Setting of Revision Anterior Cruciate Ligament Reconstruction: 6-Year Follow-up Results From the MARS Cohort. The American journal of sports medicine Fox, J. A., Huston, L. J., Haas, A. K., Pennings, J. S., Allen, C. R., Cooper, D. E., DeBerardino, T. M., Dunn, W. R., Lantz, B. B., Spindler, K. P., Stuart, M. J., Amendola, A. N., Annunziata, C. C., Arciero, R. A., Bach, B. R., Baker, C. L., Bartolozzi, A. R., Baumgarten, K. M., Berg, J. H., Bernas, G. A., Brockmeier, S. F., Brophy, R. H., Bush-Joseph, C. A., Brad Butler V, J., Carey, J. L., Carpenter, J. E., Cole, B. J., Cooper, J. M., Cox, C. L., Creighton, R. A., David, T. S., Flanigan, D. C., Frederick, R. W., Ganley, T. J., Gatt, C. J., Gecha, S. R., Giffin, J. R., Hame, S. L., Hannafin, J. A., Harner, C. D., Harris, N. L., Hechtman, K. S., Hershman, E. B., Hoellrich, R. G., Johnson, D. C., Johnson, T. S., Jones, M. H., Kaeding, C. C., Kamath, G. V., Klootwyk, T. E., Levy, B. A., Ma, C. B., Maiers, G. P., Marx, R. G., Matava, M. J., Mathien, G. M., McAllister, D. R., McCarty, E. C., McCormack, R. G., Miller, B. S., Nissen, C. W., O'Neill, D. F., Owens, B. D., Parker, R. D., Purnell, M. L., Ramappa, A. J., Rauh, M. A., Rettig, A. C., Sekiya, J. K., Shea, K. G., Sherman, O. H., Slauterbeck, J. R., Smith, M. V., Spang, J. T., Svoboda, C. R., Taft, T. N., Tenuta, J. J., Tingstad, E. M., Vidal, A. F., Viskontas, D. G., White, R. A., Williams, J. S., Wolcott, M. L., Wolf, B. R., York, J. J., Wright, R. W. 2025: 3635465251387333

    Abstract

    Meniscal preservation has been demonstrated to contribute to long-term knee health and has been a successful intervention in isolation and in patients with anterior cruciate ligament reconstruction (ACLR). The long-term results of meniscal repair in the setting of revision ACLR have yet to be documented.To report the incidence of meniscal repair failures at the 6-year follow-up in a cohort of patients who underwent concurrent revision ACLR and primary meniscal repair.Prospective cohort study; Level of evidence, 2.All revision ACLRs with concomitant primary meniscal repair cases from a multicenter group between 2006 and 2011 were selected. Six-year follow-up was obtained to determine whether any subsequent surgery had occurred since their initial revision ACLR. If so, operative reports were obtained, whenever possible, to verify pathological condition and treatment.In total, 221 patients from 1234 revision ACLRs underwent concurrent primary meniscal repairs (18% of the cohort). There were 238 repairs performed: 173 medial and 65 lateral. The majority of these repairs (n = 181; 76%) were performed with an all-inside technique. Six-year surgical follow-up was obtained in 77% (171/221) of the cohort, or 189 of 238 (79%) of the repairs (136 medial, 53 lateral). The meniscal repair failure rate, defined as reoperation, was 16% (31/189) at 6 years. Of the 31 failures, 28 were medial (24 all-inside, 4 inside-out; 28/136 = 20.6% failure rate) and 3 were lateral (2 all-inside, 1 inside-out; 3/53 = 5.7% failure rate). Three medial failures were treated in conjunction with a subsequent repeat revision ACLR. Medial tears underwent reoperation for failure at a significantly higher rate than lateral tears (20.6% vs 5.7%; P = .01) and had a significantly shorter survival time compared with lateral tears (P = .02). No difference was found between the failure and nonfailure groups when it came to tear type, tear length, repair technique utilized, suture/implant type, or number of sutures used between the 2 groups.Meniscal repair in the revision ACLR setting has a 16% failure rate at 6 years. Failure rates for medial tears (20.6%) were found to be higher than that for lateral tears (5.7%), which aligns with previous studies in both the revision and primary ACLR setting.

    View details for DOI 10.1177/03635465251387333

    View details for PubMedID 41220248

  • All-Inside Meniscal Implant Placement and Risks of Neurovascular Injury: An Arthroscopic, Pediatric Anatomic Study. Orthopaedic journal of sports medicine Baird, H. B., Yen, Y. M., Baird, W., Taylor, V., Thomas, N., Obilo, C., Lind, D., Schultz, C., Swanson, M., Beck, J., Franklin, C., Landrum, K., Tompkins, M., Schmitz, M., Wilson, P., Ganley, T., Ellis, H. B., Shea, K. 2025; 13 (11): 23259671251391350

    Abstract

    Pediatric meniscal injury rates and their arthroscopic repair are on the rise. With the growing popularity of all-inside devices used in this potentially higher-risk population, studies examining the proximity of these devices to neurovascular structures are needed.The purpose of this study was to provide distances to neurovascular structures from all-inside devices placed arthroscopically at both high-risk approach angles and zones of the lateral menisci of pediatric cadaveric specimens. It was hypothesized that the neurovascular structures would be situated closely to arthroscopically placed all-inside lateral meniscal devices, particularly the popliteal artery (PA), popliteal vein (PV), and tibial nerve (TN) to devices placed at the posterior root when placed via a lateral portal, as well as the peroneal nerve (PN) to devices placed just medial to the popliteal hiatus via a medial portal.Descriptive laboratory study.The study involved 12 fresh-frozen cadaveric knee specimens (6 matched pairs) between the ages of 6 and 10. Two all-inside meniscal repair implants were placed in the lateral meniscus: 1 via a medial port just medial to the popliteal hiatus and 1 via a lateral port at the visible edge of the posterior root. Specimens were then dissected posteriorly to expose the posterior knee capsule and meniscal implants. The distance measurements between the implants and the PA, PV, TN, and PN were recorded.The distances from the anchors to the PA, PV, TN, and PN ranged from 2.3 to 59.8 mm, 3.5 to 58.0 mm, 5.3 to 63.0 mm, and 6.3 to 40.1 mm, respectively. Implants at the meniscus root were closer to the PA, PV, and TN than implants at the popliteal hiatus (P≤ .001 for all). There was no statistically significant difference in distances to the PN between the 2 implant positions (P = .06).This study illustrates the proximity of neurovascular structures to all-inside devices in pediatric knee specimens, particularly those directed at the posterior horn using the anterolateral portal. Under the conditions of this study, all-inside devices appeared to be safe.This study provides much-needed data to the growing body of knowledge regarding meniscal injuries and repair in the pediatric population.

    View details for DOI 10.1177/23259671251391350

    View details for PubMedID 41244230

    View details for PubMedCentralID PMC12618832

For Complete list of Dr. Shea's Publications visit any of the links below 

Faculty Contact

Dr. Kevin Shea

Research Contact

Bryan Khoo

bkhoo@stanford.edu