John Gabriel Horneff, III, MD, FAAOS

Orthopaedic Surgery
Accepting new patients
Sees patients age 18 and up
Penn Orthopaedics Pennsylvania Hospital - Cathcart Building
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Penn Medicine Provider

About me

  • Director, Shoulder and Elbow Fellowship
  • Associate Professor of Clinical Orthopaedic Surgery

Dr. Gabe Horneff is a board certified orthopaedic surgeon specializing in the treatment of shoulder and elbow conditions. Originally from southern New Jersey, he completed medical school and residency at the University of Pennsylvania. He was then awarded a fellowship in Shoulder and Elbow Surgery at the Rothman Institute at Thomas Jefferson University.

Dr. Horneff has been the recipient of numerous awards including the Joseph P. Iannotti Award for Excellence in Shoulder Surgery as well as the Rockwood Clinical Grant in Shoulder Care. He performs a variety of surgical procedures on the shoulder and elbow including arthroscopic surgery, fracture care, and arthroplasty for arthritic conditions.

Dr. Horneff has published many original papers, abstracts, and book chapters in the field of orthopaedic surgery with a focus on shoulder and elbow care. He remains academically active with a dedication to ongoing research of the shoulder and elbow. He current serves on multiple committees as a fellow of the American Academy of Orthopedic Surgeons (FAAOS) and as a member of the American Shoulder and Elbow Society.

My education and training

  • Medical School: University of Pennsylvania School of Medicine
  • Residency: University of Pennsylvania Health System
  • Fellowship: Thomas Jefferson University Hospital

Reviews

Average Rating

1656 reviews

Comments are submitted by patients and reflect their views and opinions. The comments are not endorsed by and do not necessarily reflect the views of Penn Medicine.

Anonymous
April 2026
he was attentive, asked questions and listened to the answers. wasn't just going through the motions (so to speak).
Anonymous
April 2026
he was fantastic
Anonymous
April 2026
he provided additional information and a prescription for pain management
Anonymous
April 2026
great bedside manner

Insurance accepted

Please contact the practice and/or the member services department of your insurance company for specific details before receiving services. Providers may participate in some, but not all, products offered by a health plan; providers may also accept plans at some practice locations but not others.

Locations

Penn Medicine hospital privileges

  • Hospital of the University of Pennsylvania: Has privileges to treat patients in the hospital.
  • Pennsylvania Hospital: Has privileges to treat patients in the hospital.
  • Penn Presbyterian Medical Center: Has privileges to treat patients in the hospital.
Dr. Horneff is a Penn Medicine physician. In New Jersey, providers are affiliated with Penn Medicine through Clinical Health Care Associates of New Jersey or Princeton Healthcare Affiliated Physicians, PC.

Qualifications and experience

Treatments and Conditions

Research

Publications

Boutros M, Awad G, Adio A, Lawand J, Boufadel P, Khan AZ, Hill BW, Horneff JG, Abboud JA. Superior compared with anteroinferior plating for mid-shaft fractures of the clavicle: a meta-analysis. , Bone Joint J, 108(5): 2026,578-587


Kaley Beall, Maria Bozoghlian, Dana Garrison, Amir Fanaei, Paul McMillan, Asim Khan, Jada Laws, Mihir Sheth, Cathy Shemo, Nick Wiley, David Glaser, Andrew Kuntz, Dylan J Cannon, Hunter Blake Carlson, Peter J Chabot, Charles Cogan, Matthew R Colatruglio, Lisa G M Friedman, Jaina A Gaudette, John Green, Lauren Grobaty, Michael Gutman, Jason C Ho, Keegan Hones, Ermyas Kahsai, Jacquelyn Kakalecik, Mitchell Kirkham, Michael A Kloby, Elliot N Konrade, Margaret C Knack, Tyler LaMonica, Amy Loveland, Joshua I Mathew, Emma Merrill, Albert D Mousad, Luke Myhre, Andrew Nahr, Jacob Nyfeler, Doug E Parsell, Midhat Patel, Marissa Pazik, Teja S Polisetty, Padmavathi Ponnuru, John Scanaliato, Arden Shen, Karch M Smith, Katherine A Sprengel, Ocean Thakar, Lacie Turnbull, Alayna Vaughan, John C Wheelwright, Anastasia Whitson, Anna B Williams, Tyler Williams, Joseph Abboud, April Armstrong, Luke Austin, Tyler Brolin, Vahid Entezari, Bassem Elhassan, Joseph Galvin, J Ryan Hill, Grant E Garrigues, Brian Grawe, Lawrence V Gulotta, Rhett Hobgood, John G Horneff, Joseph Iannotti, Jason E Hsu, Michael Khazzam, Joseph J King, Jonathan C Levy, Ryan Lohre, Sameer Nagda, Brendan Patterson, Anand Murthi, Surena Namdari, Gregory P Nicholson, Randall J Otto, Eric T Ricchetti, Glen Ross, Sarav Shah, Thomas Throckmorton, Thomas Wright, Robert Gillespie, Benjamin W Sears, Robert Z Tashjian, Peter S Johnston, Armodios M Hatzidakis, Andrew Jawa Return to sport after shoulder arthroplasty: an ASES multicenter analysis of sport-specific predictors of performance in reverse shoulder arthroplasty and total shoulder arthroplasty. , J Shoulder Elbow Surg: 2026


Kaley Beall 1, Maria Bozoghlian 5, Dana Garrison 6, Amir Fanaei 7, Paul McMillan 8, Asim Khan 9, Jada Laws 10, Mihir Sheth 11, Catherine Shemo 12, Nick Wiley 13, David Glaser 14, Andrew Kuntz 14, Dylan J Cannon 15, Hunter Blake Carlson 16, Peter J Chabot 17, Charles Cogan 12, Matthew R Colatruglio 10, Lisa G M Friedman 14, Jaina A Gaudette 9, John Green 7, Lauren Grobaty 12, Michael Gutman 18, Jason C Ho 12, Keegan Hones 19, Ermyas Kahsai 20, Jacquelyn Kakalecik 19, Mitchell Kirkham 16, Michael A Kloby 8, Elliot N Konrade 10, Margaret C Knack 10, Tyler LaMonica 19, Amy Loveland 21, Joshua L Mathew 17, Emma Merrill 16, Albert D Mousad 20, Luke Myhre 16, Andrew Nahr 10, Jacob Nyfeler 16, Doug E Parsell 22, Midhat Patel 12, Marissa Pazik 19, Teja S Polisetty 15, Padmavathi Ponnuru 23, John Scanaliato 9, Arden Shen 9, Karch M Smith 16, Katherine A Sprengel 9, Ocean Thakar 21, Lacie Turnbull 19, Alayna Vaughan 18, John C Wheelwright 16, Anastasia Whitson 20, Anna B Williams 17, Tyler Williams 9, Joseph Abboud 18, April Armstrong 23, Luke Austin 18, Tyler Brolin 10, Vahid Entezari 12, Bassem Elhassan 13, Joseph Galvin 5, J Ryan Hill 6, Grant E Garrigues 9, Brian Grawe 8, Lawrence V Gulotta 17, Rhett Hobgood 22, John G Horneff 14, Joseph Iannotti 12, Jason E Hsu 20, Michael Khazzam 24, Joseph J King 19, Jonathan C Levy 25, Ryan Lohre 13, Sameer Nagda 11, Brendan Patterson 5, Anand Murthi 21, Surena Namdari 18, Gregory P Nicholson 9, Randall J Otto 7, Eric T Ricchetti 12, Glen Ross 1, Sarav Shah 1, Thomas Throckmorton 10, Thomas Wright 19, Robert Gillespie 26, Benjamin W Sears 27, Robert Z Tashjian 16, Peter S Johnston 28, Armodios M Hatzidakis 27, Andrew Jawa 29 Return to golf after shoulder arthroplasty: an ASES multicenter study predicting performance after rTSA and aTSA. , J Shoulder Elbow Surg: 2026


17., ASES Complications of RSA Research Group; Bowler A, Glass EA, Corban J, Diestel DR, McDonald-Stahl M, Stevens CS, Arnold RP, Sahi H, Puzzitiello R, Swanson DP, Moverman MA, Lohre R, Mahendraraj KA, Le K, Dunn WR, Cannon DJ, Carlson H, Chabot PJ, Cogan C, Colatruglio MR, Friedman LG, Gaudette JA, Green J, Grobaty L, Gutman M, Ho JC, Hones K, Kahsai E, Kakalecik J, Kirkham M, Kloby MA, Konrade EN, Knack MC, LaMonica T, Loveland A, Mathew JI, Merrill E, Mousad AD, Myhre L, Nahr A, Nyfeler J, Parsell DE, Patel M, Pazik M, Polisetty TS, Ponnuru P, Scanaliato J, Shen A, Smith KM, Sprengel KA, Thakar O, Turnbull L, Vaughan A, Wheelwright JC, Whitson A, Williams AB, Williams T, Abboud J, Armstrong A, Austin L, Brolin T, Entezari V, Garrigues GE, Grawe B, Gulotta LV, Hobgood R, Horneff JG, Iannotti J, Hsu JE, Khazzam M, King JJ, Kirsch JM, Levy JC, Murthi A, Namdari S, Nicholson GP, Otto RJ, Ricchetti ET, Tashjian RZ, Throckmorton T, Wright T, Jawa A. Surgical and patient factors associated with baseplate failures after reverse shoulder arthroplasty: a study by the ASES Complications of RSA multicenter research group. , J Shoulder Elbow Surg, 35(4): 2026,965-977


Lawand JJ, Crutchfield C, Holle AM, Sogbein OA, Khawaja SR, Ghilzai U, Hill BW, Khan AZ, Horneff JG, Abboud JA. Perioperative testosterone therapy linked to higher 5-year risk of periprosthetic joint infection without increased 90-day major complications or revision rates in total shoulder arthroplasty. , Shoulder Elbow: 2026


Boutros M, Awad G, Adio A, Lawand J, Boufadel P, Khan AZ, Hill BW, Horneff JG, Abboud JA. Open reduction and internal fixation versus total elbow arthroplasty for intra-articular distal humerus fractures in patients 65 years or older: a meta-analysis. , J Am Acad Orthop Surg: 2026


Shultz CL. GLP-1s linked to increased risk of bone and joint disorders. , People Magazine: 2026


Horneff JG. “The effects of GLP-1 agonists on bone health.” , Kurian M and Lustgarten R (Hosts). Primary Care Medicine. Doctor Radio on Sirius XM Channel 110: 2026


Yup K Penn GLP-1 study finds small increase in risk of osteoporosis and gout. , The Philadelphia Inquirer: 2026


Lovelace Jr B GLP-1s may increase risk of osteoporosis and gout, new research finds. , NBC News Online: 2026


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