You planted your foot, turned, and felt your knee give. Maybe there was a pop. Maybe it swelled up by the time you got home. Now you're wondering: Is this serious? Should I go to the ER? Do I need an MRI?
Most acute knee injuries are not emergencies, and many recover very well with the right early care. But a few signs do need urgent attention. This guide walks you through what to do in the first few days, what to watch for, and when an expert assessment will help you get on the right path sooner.
The first 72 hours: protect it, don't stop it
The old advice was rest, ice, compression and elevation (RICE). Current evidence favours a more active approach, often summarized as PEACE & LOVE. In plain terms:
For the first 1 to 3 days (PEACE)
Protect: Avoid activities that clearly increase pain or make the knee feel unstable. Use crutches if you're limping badly. Short-term protection is helpful; complete rest is not.
Elevate: Raise the leg above the level of your heart when resting to help control swelling.
Avoid anti-inflammatories early (if you can): Some evidence suggests they may interfere with early tissue healing. Speak with your pharmacist or physician about the best pain relief option for you.
Compress: A tensor bandage or knee sleeve can help limit swelling.
Educate: Understand your injury and avoid unnecessary treatments. Knowledge reduces worry and helps you make good decisions.
After the first few days (LOVE)
Load: Gradually return to normal walking and daily activity as pain allows.
Optimism: A positive, confident mindset is linked to better recovery.
Vascularisation: Pain-free cardio, like a stationary bike, helps circulation and recovery.
Exercise: Gentle movement and strength work restore range of motion, strength and balance.
What about ice? Ice can help with short-term pain relief. Use it for 10 to 15 minutes at a time if it feels good, but there's little evidence it speeds healing.
Simple early exercises (if pain allows):
Heel slides: Lying on your back, slowly slide your heel toward your bottom and back out.
Quad sets: With the leg straight, tighten your thigh muscle to press the back of your knee down. Hold 5 seconds.
Straight leg raises: Tighten the thigh, then lift the straight leg about 30 cm. Lower slowly.
Keep movements gentle. Mild discomfort is okay; sharp or worsening pain means back off.
Go to the emergency department now if…
These signs need same-day medical care:
You cannot put any weight on the leg at all
The knee or kneecap looks deformed or out of place and doesn't go back
Your foot or lower leg feels numb, cold, or changes colour
Severe pain that isn't eased by rest or over-the-counter pain relief
The knee becomes hot, red and swollen with a fever
Calf pain or swelling, or shortness of breath or chest pain, in the days after the injury (possible blood clot)
Signs your knee injury may be significant
These are not emergencies, but they suggest an injury that should be assessed by an expert soon, ideally within the first couple of weeks:
You heard or felt a pop at the time of injury
The knee swelled quickly, within the first few hours (this often means bleeding inside the joint; a torn ACL is the most common cause)
You couldn't keep playing or carry on with your activity
The knee gives way or feels unstable, especially when turning or on stairs
The knee locks or catches, or you can't fully straighten it
Pain along the inside or outside joint line with twisting or squatting
A knee that is truly locked and can't straighten should be seen within a few days, as some meniscus tears need earlier specialist input.
Do I need an X-ray or MRI?
Not always, and usually not first. A skilled clinical examination can identify most knee injuries accurately.
Clinicians use a well-researched checklist called the Ottawa Knee Rules to decide when an X-ray is needed to rule out a fracture. An X-ray is recommended if any of these apply:
You are 55 or older
There is tenderness at the head of the fibula (the bony bump on the outer side, just below the knee)
The kneecap alone is tender to touch
You can't bend the knee to 90 degrees
You couldn't take 4 steps both right after the injury and when assessed
MRI is most useful when its result will change your treatment, for example when surgery is being considered. Many people with knee pain over 40 show changes on MRI that are a normal part of ageing and don't need surgery. (Read more in our post on meniscus injuries in adults over 40.)
If you already have imaging, bring the report to your appointment. If you need imaging, we'll tell you what kind and why.
What happens at the Acute Knee Injury Clinic
The AKIC at Physiomoves in Surrey is a rapid-access knee assessment for injuries less than 6 weeks old. It was created with local orthopaedic surgeons and physicians to close the gap between injury and the right care.
No referral needed. Book directly, or ask your physician to refer you.
Seen fast. Our goal is to assess you within 14 days of first contact.
Expert exam. A thorough history, physical exam and review of any imaging by a physiotherapist experienced in acute knee injuries.
Clear answers. You'll leave with a clinical or working diagnosis and a written plan.
The right next step. A personalized exercise and symptom plan, return-to-activity guidance, and a recommendation for imaging or specialist referral only when needed.
Most acute knee injuries do very well with early, guided rehab. (See why early conservative rehabilitation matters.) The sooner you know what you're dealing with, the sooner you can start.
Book your assessment
Hurt your knee in the last 6 weeks? Get expert answers and a clear plan.
Call 604-575-7477 or email panorama@physiomoves.com to book your Acute Knee Injury Clinic assessment.
This article is for general education only and is not a substitute for medical advice, diagnosis or treatment. If you are unsure whether your injury needs urgent care, contact HealthLink BC at 8-1-1 or go to your nearest emergency department.
References
Dubois B, Esculier JF. Soft-tissue injuries simply need PEACE and LOVE. British Journal of Sports Medicine. 2020;54(2):72–73.
Stiell IG, et al. Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries. JAMA. 1997;278(23):2075–2079.
Englund M, et al. Incidental meniscal findings on knee MRI in middle-aged and elderly persons. New England Journal of Medicine. 2008;359(11):1108–1115.