Acute knee injuries occur suddenly, usually from direct impact or twisting. Chronic knee pain develops gradually over time, often through overuse. If you are not sure what your injury is, try our sports injury, symptom checker.
Sudden onset knee injuries involve injury to various structures of the knee, including ligaments, tendons, cartilage, and bone. They are usually caused by collisions or twisting the knee joint. Symptoms include sudden acute pain, rapid swelling and bruising.
- ACL sprain
- MCL sprain
- PCL sprain
- LCL sprain
- Cartilage meniscus tear
- Articular/hyaline cartilage injury
- Patella tendon rupture
- Tibial plateau fracture
View all Acute injuries.
Lateral knee injuries (outside)
Lateral knee pain refers to the outside of the knee. It usually, but not always, develops gradually through overuse. The most common causes are:
- LCL sprain – lateral ligament sprain.
- Lateral cartilage meniscus tear
- Iliotibial band friction syndrome – sometimes known as runner’s knee.
View all causes of pain on the outside of the knee.
Medial knee injuries (inside)
Pain on the inside of the knee can develop gradually over time from wear and tear. Sudden onset injuries often result in injury to the medial ligament and cartilage meniscus. A major cause, particularly in older athletes, is Osteoarthritis (degeneration) of the joint. The most common causes include:
View all causes of pain on the inside of the knee.
Posterior knee pain (back)
Chronic pain, which develops gradually is likely to be from an overuse injury to hamstring tendons, which join muscles to bone. Some of the most common causes of pain at the back of the knee include:
- Hamstring tendon strain
- Biceps femoris avulsion
- Biceps femoris tendinopathy
- Baker’s cyst
- Popliteus injury
View all injuries at the back of the knee.
Anterior knee (front)
This refers to the front of the knee. Injuries often involving the patella (kneecap) or the patellar tendon which connects the patella to the tibia (shin bone). The most common causes include:
- Patellofemoral pain
- Osgood Schlatter disease
- Fat pad impingement
- Jumper’s knee (Patella tendonitis)
- Quadriceps tendinopathy
- Knee bursitis (Housemaid’s knee)
View all causes of front knee injuries.
References & futher reading
- Eck C, Bekerom M, Fu F et al. Methods to diagnose acute anterior cruciate ligament rupture: a meta-analysis of physical examinations with and without anaesthesia. Knee Surg Sports Traumatol Arthrosc 2013;21(8):1895–903.