Knee pain is one of the most common musculoskeletal complaints, affecting people of all ages. The knee is a complex joint that supports your body weight and enables movement, making it vulnerable to injury and wear.
Anatomy of the Knee
The knee joint consists of:
- Bones: Femur (thighbone), tibia (shinbone), and patella (kneecap)
- Cartilage: Menisci (shock absorbers) and articular cartilage (smooth surface for movement)
- Ligaments: ACL, PCL, MCL, LCL (provide stability)
- Tendons: Connect muscles to bones (including the patellar tendon)
- Synovial fluid: Lubricates the joint
Common Causes of Knee Pain
Osteoarthritis
The most common form of arthritis, particularly in people over 50. The cartilage that cushions the bones gradually wears away, causing pain, stiffness, and swelling. NICE guideline NG226 notes that osteoarthritis affects approximately 8.75 million people in the UK alone, and prevalence is similar worldwide.
Ligament Injuries
- ACL tears: Common in sports involving sudden stops and direction changes
- MCL injuries: Often from direct impact to the outer knee
- Symptoms: sudden pain, swelling, instability, and a "popping" sensation at the time of injury
Meniscus Tears
- Can occur from twisting the knee during sports or from age-related degeneration
- Symptoms: pain, swelling, catching or locking sensation, difficulty straightening the knee
Patellofemoral Pain Syndrome
- Pain around or behind the kneecap
- Common in runners and people who sit for long periods
- Often worsened by climbing stairs, squatting, or sitting with bent knees for prolonged periods
Tendinitis
- Inflammation of a tendon, commonly the patellar tendon (jumper's knee)
- Results from overuse, particularly in sports with jumping
Bursitis
- Inflammation of the bursae (fluid-filled sacs that cushion the knee)
- Can result from repetitive kneeling, injury, or infection
Self-Care for Knee Pain
For mild to moderate knee pain without red flags, the RICE method is recommended:
- Rest: Avoid activities that aggravate the pain
- Ice: Apply for 15–20 minutes every 2–3 hours for the first 48–72 hours
- Compression: Use an elastic bandage to reduce swelling
- Elevation: Keep the knee raised above heart level when possible
Additional measures:
- Over-the-counter pain relief (paracetamol or ibuprofen) for short-term use
- Gentle range-of-motion exercises once acute pain subsides
- Maintain a healthy weight to reduce joint stress
When to See a Specialist
Consult an orthopaedic specialist if:
- Pain persists for more than 2 weeks despite self-care
- The knee is swollen, red, or warm to the touch
- You cannot bear weight on the affected leg
- The knee "gives way" or feels unstable
- You hear or feel a pop at the time of injury
- The knee locks and cannot fully straighten or bend
- You notice visible deformity of the joint
- Pain is accompanied by fever (may indicate infection)
Treatment Options
Depending on the diagnosis, treatment may include:
- Physiotherapy: Muscle-strengthening exercises to support the joint
- Injections: Corticosteroid or hyaluronic acid injections for inflammation and lubrication
- Bracing or orthotics: To support alignment and reduce stress
- Arthroscopy: Minimally invasive surgery to repair or remove damaged tissue
- Joint replacement: For severe osteoarthritis that no longer responds to conservative treatment
NICE recommends that core treatments for osteoarthritis include exercise, weight management, and education, before considering more invasive interventions.
This article is for informational purposes only and does not replace professional medical advice. Always consult your doctor for personalised guidance.