Aching front-of-knee pain that gets worse going up stairs or sitting for long?
Patellofemoral Syndrome — your kneecap isn’t tracking in its groove correctly.
If the front of your knee aches going upstairs or after prolonged sitting, and the first few steps after a long sit are painful, patellofemoral syndrome may be the cause. Correcting muscle imbalances and movement patterns leads to significant improvement.
Quick Answer: Patellofemoral syndrome occurs when the patella (kneecap) doesn’t move smoothly in its groove on the femur. Usually caused by imbalance between the outer thigh muscles (too tight) and inner quad (VMO, too weak), causing the patella to track laterally. Common in runners and younger active people.
⚠️ Seek prompt evaluation if:
- Knee gives way or buckles
- Sudden severe swelling after injury
Symptoms of Patellofemoral Syndrome
- Front-of-knee pain (around the kneecap) — A dull aching or throbbing at or just below the kneecap.
- Worse going downstairs, running, squatting, or prolonged sitting — Activities that press the kneecap against the thighbone.
- Pain after prolonged sitting (movie-theatre knee) — The first few steps after a long sit are painful.
- Grinding or crunching sensation — A crepitus sound or feeling when bending the knee.
- Pain that builds after running — Often fine during activity but worse afterward.
Why Does It Happen?
The kneecap slides up and down in a groove in the thighbone during knee bending and straightening. When this tracking is disrupted, abnormal friction on the back of the kneecap causes pain.
Main causes:
- Weakness of the inner quadriceps (VMO) causing the kneecap to drift outward
- Weak hip abductors and external rotators allowing the knee to collapse inward
- Overpronation (foot rolling inward during walking)
- Sudden increases in training load
Pain = Alarm (sensitivity) × Load (stress)
- Load: Abnormal kneecap tracking increases localised friction
- Load: Hip and quad weakness concentrates force at the knee
- Alarm: Repeated irritation sensitises nerves around the kneecap
- Key: Correct kneecap tracking and rebalance muscles
Simple Tests to Try
Stair Test
If your front-of-knee hurts more going downstairs than upstairs, this points to patellofemoral involvement — the knee takes greater load on the downstep.
Seated-to-Standing Test
If the first few steps after sitting with your knees bent for 30+ minutes are painful (movie-theatre knee), pressure under the kneecap is likely elevated.
Our Approach at Yonsei SM Pain Clinic
Patellofemoral syndrome improves by correcting kneecap tracking and resolving muscle imbalances.
- Phase 1: Calm (Circulation HD)
Relieve inflammation around the patella and reduce tension in the lateral retinaculum. Down-shift pain sensitivity around the kneecap. - Phase 2: Activate (Circulation PT)
VMO selective strengthening and IT band release. Activate hip external rotators and abductors to restore correct kneecap tracking. - Phase 3: Integrate
Correct stair mechanics and running form if applicable. Train alignment in gait to prevent recurrence.
Frequently Asked Questions
Is patellofemoral syndrome the same as Runner’s Knee?
Yes, Runner’s Knee is a common name for patellofemoral pain syndrome. It is called Runner’s Knee because it is common in runners, but it can affect anyone who climbs stairs frequently, squats, or sits for long periods.
Should I stop running or exercising?
Complete rest is not always necessary. The key is reducing activities that reproduce sharp pain under the kneecap and gradually reloading as symptoms improve. Swimming and cycling are generally well-tolerated during recovery.
How long does it take to improve?
With appropriate treatment addressing muscle imbalances and movement patterns, many people notice improvement within 4–8 weeks. Returning to full running or sports activities may take longer depending on severity. Treatment Duration Q&A →
How is patellofemoral syndrome different from knee osteoarthritis?
Patellofemoral syndrome is a tracking problem — the kneecap is not gliding in its groove correctly. It mainly affects the front of the knee and occurs more in younger, active people. Knee osteoarthritis involves cartilage wear throughout the joint and is more common in older adults. Knee Osteoarthritis →
References
- Crossley KM et al. 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat. Br J Sports Med. 2016;50(14):839-843.
- Lack S et al. Proximal muscle rehabilitation is effective for patellofemoral pain: a systematic review with meta-analysis. Br J Sports Med. 2015;49(21):1365-1376.
- Barton CJ et al. Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome: a randomised clinical trial. BMJ. 2010;341:c6027.
- Collins NJ et al. Efficacy of nonsurgical interventions for anterior knee pain: systematic review and meta-analysis with emphasis on global assessment. Sports Med. 2012;42(1):31-49.
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