PATELLOFEMORAL MALTRACKING

 

 The Injury

  • The knee joint is made up of 3 bones: the femur (thigh bone), tibia (shin bone) and patella (kneecap). 
  • The patella is wrapped inside a quadriceps tendon that connects the thigh muscles (quadriceps) to the tibia. When the knee bends, or straightens, the patella glides in a special groove on the femur called the Patellofemoral groove.
  • Usually, when the knee is bent or straightened, the patella moves along a path that is controlled by the quadriceps muscles. However, for several reasons it may stray from this path (usually towards the outside of the knee). This is called Patellofemoral Maltracking and produces abnormal stresses on the under-surface of the patella that can cause pain. If allowed to progress, these stresses can cause damage to the articular cartilage on the patella (chondromalacia patellae) and femur. This is similar to having the front tire of a car slightly out of alignment, leading to abnormal wear on the tire.

Patellofemoral Maltracking is one of the most common causes of knee pain and can be caused by numerous factors:

  • Tightness in certain structures. (e.g. calf and hamstring muscles).
  • Weakness or incoordination in muscles that should help maintain normal patella tracking.
  • Altered hip, knee or foot posture.
  • Anatomic variations such as a shallow Patellofemoral groove.

 Signs and Symptoms

The most common symptom of is pain at the front of the knee that can occur while:
  • Ascending or, more often, descending stairs
  • Running
  • Pain can also result from prolonged sitting
  • Some people may experience instability (this can involve a sensation of insecurity or actual giving way of the knee) or locking of the knee.

 Treatment

The causes of Patellofemoral Maltracking will be specific for each person and so it is important that a treatment plan is formulated to meet the patient's individual needs. 
  • The first priority is to attempt to settle the pain, usually through  machines, rest or analgesics prescribed by a GP.
  • Once this is achieved, treatment is likely to include stretches for the calves, quadriceps, hamstrings, hip flexors, hip rotators and Illiotibial band.
  • Of even greater importance are exercises to both strengthen and improve the coordination of the vastus medialis oblique (VMO) muscle. The VMO forms part of the quadriceps muscle group and is located just above the patella, on the inner aspect of the thigh. It is believed to help maintain the patella in its correct position in the Patellofemoral groove. Methods of improving VMO function may involve EMG biofeedback machines or taping of the patella.
  • Strengthening of the quadriceps muscle group as a whole is also thought to be beneficial, but it is important to note that traditional knee extension exercises may actually exacerbate the problem through over-stressing the Patellofemoral joint. Closed-chain exercises (where the sole of the foot is in contact with a flat surface) such as the squat and split-squat are more appropriate but should only be performed in a safe, pain-free range of motion.

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