Knee Pain: Causes, Symptoms, and Management When Walking Downstairs

Why do my knees hurt when I walk downstairs?

Knee pain experienced when walking downstairs commonly stems from issues related to the patellofemoral joint, often exacerbated by the high eccentric loading required of the quadriceps muscles to control the descent.

The Biomechanics of Descending Stairs

Descending stairs is a deceptively demanding activity for the knee joint, particularly the patellofemoral joint (the articulation between the kneecap, or patella, and the thigh bone, or femur). Unlike ascending, which primarily involves concentric muscle contractions to lift the body, descending heavily relies on eccentric muscle contractions of the quadriceps.

• Eccentric Loading: As you lower your body down each step, your quadriceps muscles lengthen under tension to control the movement and absorb impact. This eccentric work places significant stress on the patellofemoral joint, as the quadriceps pull the patella against the femoral groove.
• Increased Joint Compression: The forces across the patellofemoral joint can be several times your body weight during stair descent, significantly higher than during level walking. This compression, combined with the tracking of the patella within the femoral groove, can irritate tissues if there are underlying biomechanical inefficiencies or structural issues.
• Muscle Control and Stability: Adequate strength and coordination of the quadriceps, hamstrings, and gluteal muscles are crucial for stable knee mechanics during descent. Weakness or imbalance in these muscle groups can lead to poor patellar tracking and increased stress on the joint.

Common Causes of Knee Pain When Descending Stairs

Pain during stair descent often points to conditions that are aggravated by the specific biomechanical demands of the movement.

• Patellofemoral Pain Syndrome (PFPS): Also known as "runner's knee," PFPS is one of the most common causes. It typically presents as a dull, aching pain around or behind the kneecap. It's often linked to poor patellar tracking, muscle imbalances (e.g., weak vastus medialis obliquus, tight IT band, weak glutes), or overuse.
• Osteoarthritis (OA): Degenerative changes in the articular cartilage, particularly behind the kneecap (patellofemoral OA) or in the main tibiofemoral joint, can cause pain. The increased compression and shear forces during stair descent can exacerbate the discomfort associated with cartilage wear.
• Meniscus Tears: The menisci are C-shaped cartilage pads that cushion the knee. Tears can cause pain, clicking, or locking. Descending stairs can pinch or load a torn meniscus, leading to sharp pain.
• Quadriceps Weakness or Imbalance: Insufficient strength in the quadriceps, especially the eccentric control, can lead to uncontrolled knee flexion and increased stress on the patellofemoral joint. Weakness in the gluteal muscles (gluteus medius, gluteus maximus) can also contribute by allowing excessive knee valgus (knee caving inward) during movement.
• Iliotibial Band (ITB) Syndrome: While more commonly associated with running, tightness in the IT band can increase lateral tension on the patella, contributing to tracking issues and pain, especially if combined with other predisposing factors.
• Chondromalacia Patellae: This refers to the softening and breakdown of the cartilage on the underside of the patella. It's often a precursor or component of PFPS, leading to pain with activities that load the patellofemoral joint.
• Bursitis: Inflammation of the bursae (small fluid-filled sacs that cushion joints) around the knee, such as the prepatellar or infrapatellar bursa, can cause localized pain that is aggravated by movement and pressure.
• Previous Injury or Surgery: Altered mechanics, scar tissue, or residual weakness following a prior knee injury (e.g., ACL tear, patellar dislocation) or surgery can predispose individuals to pain with activities like stair descent.

Understanding the Pain

To help identify the potential cause, consider the characteristics of your pain:

• Location: Is the pain directly behind, above, below, or to the sides of the kneecap? Does it feel deeper within the joint?
• Type of Pain: Is it a dull ache, a sharp stab, a burning sensation, or a grinding feeling?
• Accompanying Symptoms: Do you experience any clicking, popping, grinding (crepitus), swelling, warmth, or a sensation of instability or "giving way"?
• Onset: Was the pain sudden, or did it develop gradually? Is it worse after prolonged sitting with bent knees ("movie-goer's sign")?

When to Seek Professional Help

While many cases of knee pain can be managed with conservative strategies, it's important to consult a healthcare professional, such as a physical therapist or orthopedist, if you experience:

• Severe pain that limits daily activities.
• Sudden onset of pain after an injury.
• Significant swelling, redness, or warmth around the knee.
• Inability to bear weight on the leg.
• Locking, catching, or a sensation of the knee "giving out."
• Pain that doesn't improve with rest and self-care within a few weeks.

Strategies for Managing and Preventing Knee Pain

Addressing knee pain during stair descent often involves a multi-faceted approach focused on improving joint mechanics, strength, and flexibility.

• Strengthening Exercises:
  • Quadriceps Strengthening: Focus on eccentric control. Exercises like eccentric squats (slowly lowering into a squat), step-downs (slowly lowering one foot from a step), and leg extensions (controlled lowering phase) are beneficial.
  • Gluteal Strengthening: Strong glutes (maximus and medius) are vital for hip stability and preventing knee valgus. Incorporate glute bridges, clamshells, banded walks, and single-leg deadlifts.
  • Hamstring and Calf Strength: Ensure balanced strength around the knee with exercises like hamstring curls and calf raises.
• Flexibility and Mobility:
  • Quadriceps and Hip Flexor Stretching: Tightness can pull on the patella.
  • Hamstring and Calf Stretching: Important for overall lower limb mechanics.
  • IT Band Stretching/Foam Rolling: To reduce lateral tension on the knee.
• Appropriate Footwear: Wear supportive shoes with good cushioning that fit well. Avoid high heels or worn-out shoes.
• Movement Modification:
  • Slow and Controlled Descent: Consciously slow down your movement, focusing on controlled eccentric contraction.
  • Use Handrails: Utilize handrails for support to offload some of the stress from your knees.
  • Lead with the Stronger Leg: If one knee is more painful, try leading with the stronger leg and allowing the painful leg to follow in a more controlled manner.
• Activity Modification: Temporarily reduce activities that exacerbate your pain until strength and mechanics improve. Consider alternative forms of cardio like cycling or swimming.
• RICE Protocol (for acute pain):
  • Rest: Avoid activities that worsen pain.
  • Ice: Apply ice packs for 15-20 minutes several times a day to reduce inflammation.
  • Compression: Use a compression bandage to help reduce swelling.
  • Elevation: Elevate the leg above heart level when resting.

Conclusion

Knee pain when walking downstairs is a common complaint that often signals an underlying issue related to the patellofemoral joint and the eccentric demands placed on the lower limb musculature. By understanding the biomechanics involved and systematically addressing potential causes through targeted strengthening, flexibility, and movement modifications, most individuals can significantly reduce or eliminate their pain. However, persistent or severe pain warrants professional evaluation to ensure an accurate diagnosis and appropriate management plan.