Patellofemoral Angle

• This angle is also known as to quadriceps angle [ Q -angle ].
• It is defined as to angle between quadriceps muscles primarily to the rectus femoris & the patellar tendon.
• It is represented to an angle of the quadriceps muscles force.

Background of to patellofemoral angle :

• Direction & magnitude of to force produced by to quadriceps muscle have to great influence on bio mechanics of patellofemoral joint.
• Line of force which is created by to quadriceps muscle on lateral of joint line mainly due to the large cross-sectional area & this force is applied to the potential of vastus lateralis.
• Since there is exists an association between patellofemoral pathology & excessive lateral tracking of to patella.
• Assessing this overall lateral line to pull the quadriceps relative to the patella.
• It is a means of clinical measure.

Patellofemoral angle is formed between to :

• This line is representing to the resultant line of force of to quadriceps muscle which is made by connecting a point near to ASIS of to mid-point to Patella.
• Q angle is measured into a supine or standing position.
• Standing position is usually more to suitable, due to normal weight-bearing forces which are applied onto knee joint & it is occurs during daily activity.
• Traditionally, this Q angle is measured with to knee at near to full extension but not in hyper extension with to patient in supine position & quadriceps are relaxed, as to lateral forces on to patella is more of to problem into circumstances.
• With to knee flexed patella is set into intercondylar notch & even a very large to lateral force on to patella.
• It is unlikely to result in dislocation.
• Q angle is reduced with to knee flexion & the tibia rotates medially into relation with to femur.
• This method is regarded as to traditional or conventional.
• Q angle is also assessed into standing position.

Normal Values of to patellofemoral angle :

Position of knee	Q angle in women	Q angle in men
Straight	18′	13 ‘
In extension	< 22′	< 18 ‘
In 90 degrees of flexion	< 9′	< 8 ‘

Measuring of to patellofemoral angle :

Position of to patient :

• The patient is supine with to knee extended.
• The therapist stands next to the patient.

Application of to patient:

• When measuring of to patellofemoral angle ensure to lower extremity is at to right angle of to line joining each ASIS.
• The foot is placed in a neutral position relative to supination & pronation with to hip in a neutral position relative to medial & lateral rotation.
• Draw a line from ASIS to the midpoint of the patella and then from the midpoint of the patella to the tibial tubercle.
• This resultant angle is formed by the crossing of those two lines which is called to patellofemoral angle

.

Positive sign of patellofemoral angle :

• Normal Q angle score for females is between 13-18° with values greater than and lesser considered abnormal and may indicate the patient is at risk of developing chondromalacia patellae, patella Alta or Mal-tracking of the patella.

Problems with Measuring to patellofemoral angle :

• The problem with the use of this angle to measure the lateral pull on to patella is that the line between ASIS & the mid-patella is only an estimate of to line of pull of the quadriceps & does not necessarily reflective of the actual line of to pull in to patient which is being examined.
• If a substantial imbalance exists between to vastus medialis & vastus lateralis muscles in the patient.
• The Q angle leads to an incorrect estimate of to lateral force on to patella because the actual pull of to quadriceps muscle is no longer along to estimated line.
• Furthermore the patella is sitting into an abnormal lateral position into the femoral sulcus because of imbalanced forces, so that become a smaller Q angle because the patella lies more in line with the ASIS & tibial tuberosity.

Factors affecting to patellofemoral angle :

• When an Increase in Q angle is associated with:

• Femoral anteversion
• External tibial torsion
• Laterally displaced tibial tubercle
• Genu valgum

Clinical Importance of patellofemoral angle

• Understanding of normal anatomical & bio mechanical features of to patellofemoral joint which is essential to any evaluation of the knee function.
• Patellofemoral angle is formed by to vector for the combined pull of to quadriceps femoris muscle & the patellar tendon.
• It is important because of to lateral pull which it exerts on the patella.
• Any alteration in alignment that increases the patellofemoral angle is thought to increase lateral force on the patella.
• It is become too harmful because of an increase in lateral force which is an increase in compression of the lateral patella onto the lateral lip of the femoral sulcus.
• In to presence of a large enough lateral force, the patella is sublux/dislocated over to the femoral sulcus when the quadriceps muscle is activated by the extended knee.
• It is also suggested to have an abnormal patellofemoral angle which is also influenced by neuromuscular responses & quadriceps reflex response time.