Patella Tracking Problems Lecture

Patella Tracking Problems
Patella Tracking – The gliding motion of the patella within the
trochlear groove of the femur
Abnormal Patellar Tracking - A lateral or medial shift of the
patella while gliding within the trochlear groove
Consequences of Abnormal Patellar Tracking –
Articular cartilage damage to patella &/or femoral condyles
Some Causes of Abnormal Patella Tracking 1. Bony Abnormalities
2. Muscular/Soft Tissue Imbalances
1. BONY ABNORMALITIES
Femoral Torsion – Abnormal twisting of the femoral shaft
Types of Femoral Torsion:
a. Femoral Anteversion – A medially twisted femoral
shaft in which the anterior femoral condyles face
excessively inward
Femoral anteversion can lead to inward facing patellae
(“squinting patella”) and “toeing in” gait.
b. Femoral Retroversion – A laterally twisted femoral shaft in which the
anterior femoral condyles face excessively outward
Femoral retroversion can cause the patellae to face outward (“grasshopper
patella”) and “toeing out” gait.
Illustration left: These pictures
show “toeing in” due to
increased femoral anteversion
and “toeing out” due to femoral
retroversion
*Note: The tibia bones can also be malformed
with rotational deformities. We won’t discuss
these at this time.
The Q–Angle
Rotational deformities of the femur (and of the tibia)
can effect a measurement called the Q-angle.
Q- angle - The angle between the pull of the
quads and the patella tendon
Measurement of Q – Angle
 Place the axis of goniometer over mid patella.
 Align center of stationary arm with imaginary line
connecting ASIS & mid patella. (Have your partner
palpate their own ASIS and put their finger over it to
help you.)
 Align center of moveable arm with imaginary line
connecting tibial tuberosity with mid patella.
NOTE: “Normal” Q- angle values are about 13⁰ in males and 18⁰ in females.
GONIOMETER
←Movable Arm
Axis→
(center pin)
←Stationary Arm
2. MUSCLE IMBALANCES
Many muscles have rotational effects on the lower leg and can
thus change the Q angle and improve (or worsen) patella tracking
problems.
Hamstrings
 Biceps Femoris - externally rotates lower leg
 Semitendinosus and Semimembranosis - internally rotate
lower leg
Many muscles have attachments on the patella or on the
medial/lateral patellar retinaculum (connective tissue
that connects some thigh muscles to the patella).
Muscles that attach to the medial patellar retinaculum
tend to pull the patella in a medial direction when they
contract (vastus medialis)
Muscles that attach to the lateral patellar retinaculum
tend to pull the patella lateral direction when they
contract. (vastus lateralis and IT Band)
THE RETINACULUM OF THE KNEE – The illustration to the right
shows the direction of pull of various muscles/tendons have on the
patella (Note that the vastus lateralis, IT Band and Lateral retinaculum
have a lateral pull. The vastus medialis and medial retinaculum have a
medial pull)
The superficial fibers of the lateral retinaculum
(SLR) originate from the iliotibial band (ITB) and
the vastus lateralis (VL) fascia and insert into
the lateral margin of the patella and the
patellar tendon (PT)
Illustration to Left: Lateral right knee showing
superficial lateral retinaculum and muscles
which attach to it.
The superficial fibers of the medial
retinaculum (MSR) originate from the
vastus medialis (VM) and the Sartorius (not
shown) muscles and attach to the patella
and the patellar tendon (PT) medially.
Illustration to Right: Medial left knee
showing medial superficial retinaculum and
muscles which attach to it.
Right Knee Cadaver Dissection illustrating some
muscles/structures which attach to the retinaculum.
ITB = Iliotibial Band; VL = Vastus Lateralis; VM = Vastus
Medialis; RF = Rectus Femoris; P = Patella