GLP-1 receptor agonists are everywhere and everybody is talking about them. Most of the orthopaedic discussions have been around when to stop them before surgery. That matters, but much more is being discovered.
Here are the 7 numbers that most stood out to me as a joint replacement surgeon during a recent literature review.
1. 40%: The reduction in risk of having a hip replacement within one year for patients with known hip arthritis who are prescribed a GLP-1.
Orthopaedic Journal of Sports Medicine 2025. More than 237,000 patients studied.
2. 25%: The reduction in risk of having a knee replacement within one year in patients with known knee arthritis who are prescribed a GLP-1.
Same study as above.
3. 41.7 points: The reduction in WOMAC pain score for obese patients with moderate-to-severe arthritis on Semaglutide. [This is compared to a reduction of 27.5 points obese patients with moderate-to-severe arthritis not on a GLP-1.]
NEJM. STEP 9 trial. 2024.
4. 346,899: The number of patients in the largest systematic review and meta-analysis of GLP-1 use in THA and TKA to date. [This paper showed GLP-1 use was associated with a lower risk of PJI at 90 days (OR 0.75) and lower risk of reoperation at 90 days (OR 0.76).]
A Boston University and Mayo Clinic Analysis. JOA 2024.
5. 1.0% vs 1.8%: PJI rates in morbidly obese patients on GLP-1s versus morbidly obese patients not on GLP-1s. [BONUS: Not only was the infection rate cut nearly in half, but readmissions were reduced from 8.9% to 5.3% in patients on a GLP-1.]
HSS study. JBJS. 2025
6. 700%: The increase in GLP-1 use among non-diabetic patients over the past four years.
Multiple sources. Taken from Systematic Review, Lee, JOA, 2025.
7. $57,400 per QALY: The cost-effectiveness threshold at which GLP-1s become the preferred treatment strategy for patients with knee OA and obesity.
According to the Annals of Internal Medicine estimation published in September 2025.
The Bottom Line
GLP-1s are not a fad. They are changing our patient population (and clinical practice) right before our eyes. The more we understand their potential impact, the better we can care for our patients.
Cory Calendine, MD is an orthopaedic surgeon specializing in hip replacement and knee replacement at the Bone and Joint Institute of Tennessee in Franklin, Tennessee. Learn more at https://corycalendinemd.com
Full references.
1 and 2. Porto JR, Lavu MS, Hecht CJ 2nd, Kaelber DC, Sculco PK, Heckmann ND, Kamath AF. The Impact of Contemporary Glucagon-like Peptide-1 Receptor Agonists on the Onset, Severity, and Conversion to Arthroplasty in Hip and Knee Osteoarthritis. Orthopaedic Journal of Sports Medicine. 2025 Jan 13;13(1):23259671241297157. doi: 10.1177/23259671241297157. PMID: 39811151.
3. Bliddal H, Bays H, Czernichow S, et al; STEP 9 Study Group. Once-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis. New England Journal of Medicine. 2024 Oct 31;391(17):1573-1583. doi: 10.1056/NEJMoa2403664. PMID: 39476339.
4. Lee S, Singh K, Clark SC, Goh GS. The Impact of Glucagon-Like Peptide-1 Receptor Agonist Use on Clinical Outcomes After Total Hip and Knee Arthroplasty: A Systematic Review and Meta-Analysis of 346,899 Patients. Journal of Arthroplasty. 2025 Oct 8 [Epub ahead of print]. doi: 10.1016/j.arth.2025.09.054. PMID: 41072556.
5. Kim BI, LaValva SM, Parks ML, Sculco PK, Della Valle AG, Lee GC. Glucagon-Like Peptide-1 Receptor Agonists Decrease Medical and Surgical Complications in Morbidly Obese Patients Undergoing Primary TKA. Journal of Bone and Joint Surgery, American Volume. 2025 Feb 19;107(4):348-355. doi: 10.2106/JBJS.24.00468. PMID: 39719003.
6. Lee V, Durkee SM, Ponce BA, Coutelle N. Impact of Glucagon-Like Peptide-1 Receptor Agonists on Postoperative Outcomes in Arthroplasty: A Systematic Review. Journal of Arthroplasty. 2025 Jul 16 [Epub ahead of print]. doi: 10.1016/j.arth.2025.07.015.
7. Betensky DJ, Smith KC, Katz JN, et al. The Cost-Effectiveness of Semaglutide and Tirzepatide for Patients With Knee Osteoarthritis and Obesity. Annals of Internal Medicine. 2025;178:1549-1560. [Epub 16 September 2025]. doi: 10.7326/ANNALS-24-03609.
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