Inner Knee Pain: The 4 Most Common Causes
MCL, bursitis, meniscus, or arthritis — location and story usually tell them apart
Updated July 20262 minute read
Inner knee pain usually comes from one of four things: an MCL sprain (after a blow or twist), pes anserine bursitis (tender spot below the joint line), a medial meniscus tear (joint-line pain with twisting), or knee arthritis (deep ache with stiffness after rest). Where it hurts and how it started usually narrow it down.
Why does the inside of my knee hurt?
The inner knee is crowded real estate: the MCL ligament crosses the joint line, the medial meniscus sits inside it, the pes anserine tendons and bursa attach just below it, and the inner compartment is where knee arthritis most often shows up first. Four structures, four different problems — but each one leaves a distinct fingerprint, and two questions do most of the sorting: exactly where does it hurt, and how did it start?
How to tell them apart
| Where it hurts | How it started | Pattern | Most likely |
|---|---|---|---|
| Inner joint line and above | A blow to the outer knee, or a twist | Hurts when the knee is pushed inward; cutting and pivoting sting | MCL sprain |
| 2–3 inches below the joint line, on the shin | Gradual, no injury | Tender to the touch; stairs, standing up, knees touching in bed | Pes anserine bursitis |
| Along the joint line itself | A twist — or gradually, past middle age | Twisting and deep squats hurt; clicking, catching | Medial meniscus tear |
| Deep, whole inner knee | Slowly, over months to years | Stiff after rest, achy after activity, usually over 50 | Knee arthritis |
Two honest caveats. First, these overlap: arthritis and pes anserine bursitis often coexist, and a twist can injure the MCL and meniscus together. Second, degenerative meniscus changes and early arthritis blur into each other — which matters less than you'd think, because the first-line treatment for both is the same.
What you can try first
- Match the dose to the irritation. Halve the aggravating activity — mileage, stairs, pivot sports — for two weeks instead of stopping everything.
- Ice the sore spot 15–20 minutes after activity if it's flared.
- Start gentle strength work: sit-to-stands, bridges, comfortable step-ups. Every one of these four conditions does better with stronger hips and quads around it.
- If there was a real injury moment, protect it early and get it graded within a few days rather than waiting it out.
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When it's time to see someone
Two to three weeks of sensible self-management without progress — or a pattern you can't match above — is the evaluation threshold. Go promptly if you have any of these: a knee that locks or truly gives way, rapid swelling after an injury, inability to bear weight, calf swelling, or a hot, swollen knee with fever. The full triage guide is at when to see a PT for knee pain.
Frequently asked questions
Usually not — most of it is a load problem or a healing ligament, and all four common causes respond to conservative care. The exceptions worth prompt attention: a knee that locks or gives way, fast swelling after an injury, inability to bear weight, or a hot swollen joint with fever.
Sources (5)
- Collateral Ligament Injuries. American Academy of Orthopaedic Surgeons, OrthoInfo. — AAOS OrthoInfo
- Mohseni M, Mabrouk A, Li DA. Pes Anserine Bursitis. StatPearls. Updated 2024. — StatPearls
- Raj MA, Bubnis MA. Knee Meniscal Tears. StatPearls. — StatPearls
- Thorlund JB, et al. Arthroscopic surgery for degenerative knee: systematic review and meta-analysis of benefits and harms. BMJ. 2015. — BMJ
- Fransen M, et al. Exercise for osteoarthritis of the knee. Cochrane Database Syst Rev. 2015. — Cochrane
This article is for education only and isn't medical advice. Always talk to a licensed clinician about your specific situation.