October 2024: Once-Weekly Semaglutide in Persons with Obesity and Knee Osteoarthritis

The issue

Weekly injections of the weight‑loss drug semaglutide 2.4 mg relieved knee‑osteoarthritis pain far better than placebo while trimming body weight, with no extra serious side‑effects.

What do I need to know?

In the 68‑week STEP‑9 trial, 407 adults with obesity (average BMI 40) and moderate knee‑OA pain were randomized 2:1 to semaglutide or placebo alongside diet‑and‑exercise advice.

 Semaglutide patients lost an average 13.7 % of body weight versus 3.2 % with placebo and saw WOMAC pain scores fall by 41.7 points versus 27.5 points. Physical‑function scores (SF‑36) improved almost twice as much.

 Serious adverse events occurred in 10 % vs 8 %, a non‑significant difference; most discontinuations were for gastrointestinal upset.

Potential risk of weight‑related knee‑OA progression

Recommended Actions

Track weight and knee pain every 3–6 months.

Start or maintain low‑impact activity (cycling, pool walking) and balanced, calorie‑controlled meals.

Ask the clinician whether early weight‑loss therapy could delay worsening arthritis.

Imminent risk of weight‑related knee‑OA progression

Recommended Actions

Discuss eligibility for once‑weekly semaglutide (BMI ≥ 30 plus moderate knee pain).

Arrange baseline labs and review current pain meds to minimize overlap with GI‑side‑effect drugs.

Recheck weight and WOMAC pain at 3‑month intervals; escalate dose per protocol if tolerated.

Confirmed disabling knee osteoarthritis with obesity

Recommended Actions

Use semaglutide alongside physical therapy; add analgesics or joint injections only as needed.

Monitor for nausea, vomiting, or rapid weight loss; pause dose titration if symptoms persist.

Reassess surgical options once significant weight reduction and pain control are achieved.

What can I do?

Tell the doctor, “Am I at potential, imminent, or confirmed risk, and would semaglutide help both my weight and knee pain?” Bring a 1‑month pain diary and current medication list. If starting treatment, inject the dose on the same day each week, continue gentle exercise, and note any stomach upset or knee‑function improvements to share at follow‑up visits.