Causes of Knee Pain

Knee pain is very common in all ages and demographics. Whether you are a runner, walker, and/or avid gardener knee pain is very common. When the knee pain is related to direct trauma, the evaluation process can be focused on the knee itself. However, if the knee pain is insidious or due to overuse, practitioner has to check patient’s hip and low back area to determine contributing factors.

Causes of Knee Pain

Knee Joints Anatomy

Knee complex is made of 3 joints or articulations.

  1. Tibiofemoral joint
  2. Tibiofibular joint
  3. Patellofemoral articulation

Furthermore, knee is reinforced by muscles, ligaments, meniscus, cartilage and bursas. All of those structures need to work coherently or in unison not to produce pain.

What Can Cause Knee Pain

  • Musculature surrounding the knee
  • Ligaments
  • Meniscus
  • Cartilage damage
  • Bursa

In this article we will discuss all of those structures, mechanisms of injury and symptoms of each and every part of the knee.

Traumatic Type Injury to the Knee

Ligament Injury

There are 4 ligaments within the knee. Ligaments are made of elastic tissue that connects two adjacent bones and provide stability and strength to the joint. Here are the four ligaments of the knee and their functional role.

  • (ACL) Anterior Cruciate Ligament: ACL is located inside the knee and connect the shin bone to thigh bone. It prevents forward movement of femur onto the shin bone.
  • (PCL) Posterior Cruciate Ligament: is located back of the knee and also attached between thigh bone and shin bone. It prevents backwards movement shin bone onto thigh bone
  • (MCL) Medial Cruciate Ligament: MCL provides the stability to the knee and prevents the knee from buckling inwards
  • (LCL) Lateral Cruciate Ligament: located on the outside part of the knee, provides stability.

Causes of Knee Pain

Mechanism of Injury of the ligaments in the knee

ACL is most common ligament to be injured during sport events or even recreational/leisure sports. ACL injury occurs during sudden change of direction or rotation of the knee on the planted foot.

PCL also a common injured ligament however, PCL injury occurs during the impact when the shin bone driven backwards. Patient usually hears a pop noise inside the knee with severe pain.

MCL injury usually occurs due to impact to the outside part of the knee and knee itself gets driven inwards. Once again patient may describe the pop noise.

Signs and Symptoms of the Ligament injury in the knee

Everyone feels pain differently so, there is never a text book signs and symptoms for any kind of injury. If there is a complete tear to the ligament, there might NO pain at all. However, onset of swelling is rapid due to vascularity (blood supply to the effected tendon). Furthermore, one of the key findings for the ligament injury is instability of the knee joint. Patient may describe “I feel like my knee just buckles under me”.

Quick Notes for the Ligament Injury

  • Traumatic event
  • Pain or NO pain (depends on the grade of the tear)
  • Swelling (hematoma) à blue, red discoloration
  • Instability

Meniscus Tear

Function: There are two meniscus in the knee, a medial meniscus and the lateral meniscus. Meniscus play a vital role for the functionality of the knee joint. They provide stability, distribute axial load, absorb shock, lubricate and nutrition the knee joint.

Causes of Knee Pain

Mechanism of injury

Patient usually presents with a knee pain following rotary type of movement through the knee. Rotary movement usually involves the flexion of the knee and internal rotation of tibia (shin bone). That movement causes the traction of the back/rear side of the medial meniscus causing the tear or irritation.

NON-Traumatic Type of knee injury

Patellofemoral Pain Syndrome (PFPS)

Sings and symptoms

Classical presentation is the pain in the front of the knee. Pain is aggravated by going up or down the stairs and with prolonged sitting (movie theater sign).

  • Knee pain
  • Aggravated by sitting and climbing stairs

Causes of Knee Pain


PFPS is primarily a soft tissues disorder that contributes to patellar (knee cap) gliding/tracking malfunction.

Structures/Causes for PFPS:

  • Slow activation of glutes (buttock muscle group)
  • Slow activation of thigh muscles
  • Shortened quadriceps muscles (thigh muscles)
  • Hyper-mobile knee cap


The main goal is to correct the patellar (knee cap) tracking and muscle activation in the quad and glutes (see knee pain treatment article on this topic).

  • Restore muscle fibres
  • Glute activation
  • Quadriceps activation
  • Stabilization exercises

Iliotibial Band Syndrome (IT Band Syndrome)

Signs and symptoms

Pain on the outer part of the knee that progressively worsens over few days/weeks period. Pain usually aggravated by walking, running, wearing high heels and especially pain gets worse with downhill running/walking. Pain occurs during the heel strike on the ground when the knee is fully extended.

Iliotibial Band Syndrome (IT Band Syndrome)

Relevant anatomy

IT band runs on the outside part of the thigh and connects just below the knee. IT band is very close in proximity to the glutes and TFL muscles and have similar action.


One of the causes for the IT band syndrome is tight IT Band itself or poor activation of the glutes. ITB syndrome may also be caused by the increased activity level and over pronation while running/walking downhill.


Due to thickness and histological structure of the IT band, stretching it has minimal effect of preventing the ITB syndrome and eliminating the pain on the outer part of the knee.

When treating the ITB syndrome it is vitally important to address the biomechanics of the hip, knee and ankles to identify what is the true cause for the lateral knee pain.

Patellar Tendinitis (Jumper’s Knee)

Signs and Symptoms

Front of the knee pain while jumping or sprinting. Patient is usually athletic and plays the sport where it is required to jump and sprint. Pain worsens during the knee is flexion at 90 degree while under the load.


The cause for an injury is the repetitive stress on the patellar tendon while jumping and sprinting. Patellar tendon irritation occurs during eccentric phase (lengthening of the muscle while contracting the same muscle).

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