Quick Answer
After receiving a cortisone shot in the knee, it is generally recommended to avoid strenuous activities and take it easy on the knee for 1-2 days. This allows the medication to start working and gives the knee time to rest and recover. However, staying completely off the knee or being immobilized for an extended period is not necessary in most cases and can lead to stiffness. Light activity and movement is encouraged after a couple of days of rest to prevent complications.
How long to rest the knee after a cortisone injection?
Most doctors recommend staying off the knee and avoiding strenuous activity for 24-48 hours after a cortisone injection. Here are the general guidelines for knee rest after a cortisone shot:
| Timeframe | Activity Level |
| First 24 hours | Completely rest the knee – no weight bearing activities |
| 24 – 48 hours | Only light activity around the house, no exercise |
| 2 – 7 days | Gradually increase light activity and movement |
| After 1 week | Slowly return to normal activities as tolerated |
During the initial 24-48 hours after the injection, strenuous exercise and activities like running, jumping, heavy lifting, and climbing stairs should be avoided to allow the corticosteroid medication time to start having an effect and reduce inflammation.
However, recent evidence suggests that staying completely immobilized or on strict bed rest can be detrimental. Complete inactivity for more than 2-3 days can lead to increased stiffness, muscle weakness, and loss of mobility.
Therefore, after the first couple days of rest, it is recommended to slowly increase light physical activity and gently move the knee to avoid complications. Low impact activities like walking, stationary cycling, and range of motion exercises can help recovery.
Why stay off the knee initially?
There are a few key reasons doctors often recommend resting the knee and limiting activity immediately after a cortisone injection:
Allows corticosteroid to start working
It takes at least 24 hours for the corticosteroid medication to start having an anti-inflammatory effect and relieve pain and swelling. Avoiding activity reduces stress on the knee so the corticosteroid can work.
Avoids damage to the joint
Right after the injection, there may be some temporary weakening or instability in the knee joint. Restricting activity helps prevent any damage or injury while the corticosteroid is taking effect.
Prevents medication from spreading
Avoiding movement and weight-bearing can help prevent the corticosteroid from spreading out of the injection site too quickly before it has time to act.
Lets the body rest and start healing
Rest allows any irritated structures in the knee to calm down. It gives surrounding muscles and soft tissues time to begin healing after the injection procedure.
So in summary, the initial 24-48 hour period of knee rest allows the treatment to start working while protecting the joint. However, extended strict immobilization can hinder the healing process.
Benefits of light knee movement after 48 hours
While initial rest is helpful, light activity and knee mobility after 1-2 days offers many benefits:
Improves blood flow
Gentle movement helps increase blood flow to nourish knee tissues and enhance corticosteroid delivery.
Prevents stiffness and weakness
Complete inactivity beyond 48 hours can result in joint stiffness, weak muscles, and decreased function. Light activity maintains mobility.
Aids recovery of muscle strength
Controlled, gradual loading and movement assists in rebuilding knee muscle strength after injection.
Lubricates knee joint
Motion facilitates synovial fluid distribution to nourish cartilage and lubricate the joint surface.
Reduces risk of blood clots
Some light activity lowers the chances of developing a venous thromboembolism (VTE) after cortisone injection.
Maintains healthy range of motion
Gentle exercises prevent restricted mobility that could delay rehabilitation after injection.
Therefore, while initially avoiding strenuous activities, incorporating light movements and range of motion exercises after 1-2 days aids in optimizing outcomes.
What activities should I avoid after knee injection?
Though light activity can be beneficial, certain motions and higher impact activities should still be avoided, especially within the first 1-2 weeks after the cortisone shot. Activities to avoid include:
- Running or jogging
- Jumping and cutting motions
- Heavy squats or lunges
- Twisting the knee forcefully
- Kneeling or stooping repeatedly
- Impact exercises like plyometrics
- Contact sports or activities with cutting
- Aggressive stretches into painful ranges
The injected knee needs more time to recover its structural integrity and stability. Prematurely stressing the joint with higher loads risks damaging tissues while they are still healing.
As knee pain and inflammation subside over 1-2 weeks, a gradual return to normal activities can be initiated. But the knee should continue to be protected against sudden twists and uncontrolled loads that could re-injure it.
What exercises can I do after a knee cortisone injection?
The right exercises after a cortisone shot can promote healing without overstressing the knee. Here are some safe knee exercises after injection:
Range of motion exercises
Gentle range of motion exercises like knee bends, leg raises, and circles help prevent stiffness and maintain mobility. They can be started from 24-48 hours onwards.
Muscle strengthening
Light quadriceps sets, straight leg raises, and calf raises help maintain muscle strength. These can begin 3-5 days after injection.
Low impact cardio
Stationary cycling, swimming, or elliptical workouts are ideal cardio exercises that avoid knee pounding. Usually safe to resume 1 week afterwards.
Balancing exercises
Static balancing on one leg helps improve proprioception and stability. Can be done holding support if needed.
Light resistance training
Controlled knee extension and hamstring curls with resistance bands or weights help build strength.
So in summary, low-impact and gentle knee mobilization exercises can safely rehabilitate the joint after a few days of rest. High intensity activities should be avoided for at least 1-2 weeks post-injection.
How long does relief last after a knee injection?
On average, the pain relieving effects of a corticosteroid injection into the knee may last between 1-6 months, but there is considerable variability. Here are some factors that influence duration of relief:
- The underlying condition – Osteoarthritis usually has shorter pain relief than inflammatory arthritis
- Location and severity of damage – More extensive joint changes may lead to shorter symptom relief
- Type of corticosteroid – Longer acting preparations (eg. methylprednisolone) may provide longer effects
- Single vs repeat injections – Some studies show repeat injections extend duration of relief
- Adjunct treatments – Physical therapy and exercise maintain benefits for longer
- Individual variation – Each patient responds differently to the injection
On average, a single corticosteroid injection into the knee provides approximately 4-8 weeks of pain relief. However, the duration can be highly variable from weeks to months.
If pain relief starts wearing off, repeating the injection may help prolong the beneficial effects. But usually no more than 3-4 injections are given within a 6 month time frame due to risks.
Risks and side effects
Corticosteroid injections into the knee are generally safe, but carry some potential risks and side effects:
Pain flare up
Some patients experience a temporary increase in pain for the first 24-48 hours before improvement of symptoms.
Infection
The estimated infection rate is less than 1%. Signs include increased knee pain, swelling, warmth and redness.
Bleeding and bruising
A small amount bleeding or bruising at the injection site is common and usually not serious.
Nerve injury
Very rare complication. Temporary or permanent nerve damage is possible.
Tendon rupture
Rare cases of weakened tendons leading to rupture have been reported.
Thinning cartilage
Repeated injections may accelerate cartilage breakdown. Limit to 3-4 per year.
Lightening skin
Skin around the injection site may temporarily lose pigment after the shot.
So while generally low risk, potential complications should be discussed with the provider before getting a knee injection. Proper sterile technique reduces risks.
Conclusion
It is generally advised to avoid strenuous knee activities and rest the joint for 1-2 days after receiving a cortisone injection. This allows the medication time to start working while protecting the knee initially. However, prolonged strict immobilization is not recommended as it can impair recovery. Low impact exercise and light knee mobility should be resumed after 48 hours to prevent complications like stiffness. Most patients can gradually return to normal activities within 7-10 days, though higher impact sports may need a longer recovery time of 2-4 weeks. While potentially providing significant pain relief, injections do carry some risks that should be considered.