How Foot Instability Affects Your Knees
Your kneecap (patella) sits within a tendon that crosses the front of your knee joint. When your foot posture is unstable—especially during walking or running—it can disrupt the alignment of your leg, placing excess pressure beneath the kneecap. This leads to patello-femoral pain syndrome (PFPS), a condition responsible for nearly 1 in 4 running-related injuries.
PFPS is more common in women, often beginning in adolescence when sports participation is high. Symptoms may persist for months or years if left untreated.
Symptoms of PFPS
You may notice:
- A dull ache around or behind the kneecap, especially during running, jumping, or stair climbing
- Discomfort when sitting with knees bent (known as the “theater sign”)
- Knee stiffness or swelling
- Cracking or popping sounds
- Muscle weakness, especially in the quadriceps, which may cause your leg to “give out”
Why It Happens: Anatomy & Biomechanics
PFPS stems from how your quadriceps and patella interact:
- The quadriceps muscle group originates at the pelvis and attaches to the patella.
- The patellar ligament connects the patella to the tibia.
- The patella acts like a pulley, gliding in a groove on the femur as your knee bends.
When the quadriceps muscles are balanced, the patella tracks smoothly. But if one muscle—especially the vastus medialis—is weak, or if surrounding tissues are tight, the patella may shift out of alignment.
The Role of Q Angle
The Q angle is the angle formed between two lines:
- From the front of the hip (ASIS) to the center of the patella
- From the patella to the tibial tubercle
A larger Q angle—common in females due to wider hips—can cause the patella to shift laterally, increasing pressure and pain. This angle can also increase with foot pronation (inward rolling of the foot).
Contributing Factors
PFPS is often caused by a combination of:
- Poor foot posture
- Unstable footwear
- High training intensity
- Occupational demands
- Anatomical variations around the knee
Treatment Options
PFPS is typically managed without surgery. Recommended strategies include:
- Rest and activity modification
- Ice therapy
- Anti-inflammatory medications
- Physiotherapy and muscle strengthening
- Stretching and massage
- Knee taping or bracing
- Custom foot orthotics and supportive footwear
If symptoms persist, your chiropodist may refer you to a physiotherapist, sports medicine physician, or orthopedic specialist.
When to Seek Help
If you’re experiencing pain beneath your kneecap, don’t wait. Early evaluation by a chiropodist or podiatrist can prevent long-term damage and help restore proper alignment
References
- Global research trends and hotspots in patellofemoral pain syndrome from 2000 to 2023: a bibliometric and visualization study. Frontiers in Medicine. 2024.
- Effect of physiotherapy interventions on pain management, function and quality of life in patellofemoral pain syndrome: A systematic review protocol. PLOS One.
- Effects of functional strength training on pain, function, and lower extremity biomechanics in patients with patellofemoral pain syndrome: a randomized clinical trial. Journal of Orthopaedic Surgery and Research. 2025.
- The immediate effects of foot orthoses on functional performance in individuals with patellofemoral pain syndrome. British Journal of Sports Medicine. 2011;45(3):193–197.