ANTERIOR KNEE PAIN OVERVIEW

ANTERIOR KNEE PAIN OVERVIEW

 

Anterior Knee Pain (AKP)

-Non-specific term that encompasses multiple diagnoses

-Multiple pain generators

-Common diagnoses:

  -Patellofemoral Instability: patellar dislocation, subluxation
  - Patellofemoral Pain Syndrome (PFPS)
  -Patellar Tendonitis
  -Osgood Schlatter's
  -Synovial Impingement Syndrome
  -Bursitis
  -Chondromalacia
  -Fat pad irritation
  -Iliotibial band syndrome

 

ocs invertabelt blog education free study guide anterior knee pain oakford group andrew champion andy

 

 

Biomechanics

-Hinge joint

-Patella: Largest sesamoid bone in the body

-Patella acts as a lever and increase extension force by 1.5x

-During flexion patella moves medial and slides into trochlear grove

-Maximum contact pressure at 90 degrees of knee flexion

Forces through the knee

  • ½ body weight with walking
  • 3-4x body weight up stairs
  • 7-8 x body weight squatting

Factors contributing to anterior knee pain

-Trochlear groove dysplasia may be predisposed anatomical factor

-VMO

-Weakness
-Delayed neuromuscular firing pattern
-Improper WMO to VL strength ratio
-Abnormal tissue length
  -Tight quadricep increases the patellofemoral (PF) contact force
  -Tight hamstring and calf create a constant flexion moment on the PF
  -Tight IT Band contributes to lateral tilt

 

KNEE EXAMINATION

Subjective Interview

-Onset

  -Acute or chronic

-Pain

  -Location
  -Characteristics- sharp/stabbing/achiness/stiffness Etc.
  -Provocation/relief
  -Swelling/inflammation characteristics

Instability

  -Knee "gives out" buckles
  -Catching/clicking
  -True instability versus weakness (quadricep inhibitory reflex)

Objective measures

Observation: static versus dynamic

  Static-When patient is not moving

  -Femoral anteversion/retroversion
  -Knee positioning (valgus/Varus)
  -Q-angle-Normal 10-22 degrees (increase q-angle has demonstrated increase  risk of PFPS)
  -Foot/Ankle (pronation/supination)

  Dynamic- Alignment observed during movement patterns

 -Typically, due to weakness or poor motor control
  -Test using 6-inch step or forward lunge
  -Abnormal movements of the patella in the trochlea groove
-Excessive contralateral hip drop
-Hip abduction and IR
-Tibial ER
-Hyper pronation

 Seated testing:

-+ "j Sing", lateral tracking