Runner's Knee & PFPS PDF

DR. MONA SELIM by the end of this lecture the student would be able to: Review the functional anatomy of knee joint Recognize the mechanical principles of knee j. Define the anterior knee pain syndrome. Detect the causes of the anterior knee pain syndrome. Recognize the signs and symptoms of the an...

DR. MONA SELIM by the end of this lecture the student would be able to: Review the functional anatomy of knee joint Recognize the mechanical principles of knee j. Define the anterior knee pain syndrome. Detect the causes of the anterior knee pain syndrome. Recognize the signs and symptoms of the anterior knee pain syndrome Plan an appropriate rehabilitation program. Anatomy of the knee 3 Bones–Tibia, Femur, Patella 2 articulations Tibiofemoral and Patellofemoral. 4 Ligaments –MCL, LCL, ACL, PCL 2 Menisci Articular Cartilage Dr. mona Selim Dr. mona Selim  Tibio-femoral Joint Closed Packed Position Full Extension with external rotation Loose Packed Position 25° of Flexion Capsular Position Flexion more limited than extension Patellofemoral joint Closed Packed Position  Full knee flexion Resting Position Full extension Capsular Position Flexion more limited than extension Dr. mona Selim Dr. mona Selim A) Femoral mechanical axis: Center of femoral head to centre knee. Dr. mona Selim B) Femoral anatomical axis: centre of femoral shaft to center of knee joint. 6o outwards from mechanical axis. Dr. mona Selim Dr. mona Selim Locking knee on full extension requires knee rotation about 5-10 degrees. Screw home rotation is different from axial rotation that occur at knee it is a couple rotation, linked mechanically to flexion and extension kinematics and cant be performed independently. Based on observable twisting of knee during last degrees of extension. It is considered a key element to knee stability for standing upright. In tibio-femoral extension: the tibia externally rotates about 10 degrees.  In femoro-tibial extension (rising from squat): The femur internally rotates on fixed tibia. Regardless whether tibia or femur is rotating the knee is externally rotated 10 degrees when fully extended. 1- shape of femoral condyles 2- passive tension in the anterior cruciate ligament. 3- lateral pull of quadriceps tendon.  to unlock the knee that is fully extended:  the joint must first internally rotate by poplitues muscle that is both internal rotator and flexor of the knee joint.  Q angle defines the normal anatomical alignment of the patella.  Q angle is a valgus angle which is formed by 2 imaginary lines: 1. Extends from the ASIS to mid-patella. 2. Extends from mid-patella to the tibial tuberosity. The magnitude of this angle is10-12 in males and 15-17 in females Mona Selim -Biomechanics of patellofemoral joint are affected by patellar tendon length & the Q angle; -Q angle is increased by: genu valgum, Increased femoral anteversion, external tibial torsion, laterally positioned tibial tuberosity, tight lateral retinaculum Method: A line is then drawn from the ASIS to the midpoint of the patella on the same side and from the tibial tubercle to the midpoint of the patella. The angle formed by the crossing of these two lines is called the Q-angle. Normal result: Normally, the Q-angle is 13° for males and 18° for females when the knee is straight Clinical Determination: -the Q angle may not be accurate in extension, since a laterally dislocated patella may give the false impression that the Q angle is normal; -in flexion, this is not a problem since the patella is well seated in the trochlear groove; -a sitting Q angle of more than 8 deg is abnormal Mona Selim  The normal alignment of the patella is maintained by: 1. Iliotibial band & lateral retinaculum laterally. 2. Vastus medialis medially 3. Patellar tendon inferiorly. 4. Quadriceps tendon superiorly. Mona Selim The resultant lateral traction force on the patella result from forces acting on the patella Mona Selim At 135 degrees of flexion: medial, lateral facets. At 90 degrees of flexion: superior pole Between 90 to 60 degrees of flexion Patella occupy its greatest contact area with the trochlear groove(30% of total surface area of the patella)……….what the clinical significant ??!! Last 20 degrees of flexion: migrate to the inferior pole Full extension: Patella rest completely above the inter-condylar groove against supra patellar fat pads Mona Selim Mona Selim Greatest patellar stress is at (60 -75degrees) so pain may be provoked in these ranges when maximum resistance force is applied in these ranges There is little or no contact of the patella with the trochlear groove from 0 to 15 of flexion so pain felt in that range could derive from irritation of the patellar fat pads or synovial tissue Mona Selim  Patella increases the quadriceps muscle torque by increasing the length of its moment arm.  In fully flexed knee patella lies completely in the inter-condylar groove→ its contribution is very small. Mona Selim As the knee is extended patella rises from the inter-condylar groove and quadriceps moment arm lengthens. Beyond 45, knee extensors moment arm is slightly decreased and therefore quadriceps muscle force is increased. In the last 15 of extension quadriceps muscle force increases by 60-100% to extend the knee joint. Mona Selim Biomechanical function of (PFJ)  1)Frog eye (grass hopper )patella: patella faces laterally &upward  2)Squinting patella :faces inward &down ward  3)Rotated inward –outward Mona Selim  a)patella alta :patella higher than normal Patella Baja b)patella baja: patella lower than Patella Alta normal Mona Selim  Normal Facing Forward Patella Alta Patella Baja During knee flexion and extension the patella moves vertically about 8 cm in the intercondylar groove, inferiorly during flexion and superiorly during extension) Mona Selim  As the knee extends → patellofemoral contact forces decrease.  In full knee extension patellofemoral contact forces are nearly zero and patella is free to move medially and laterally.  JRF = body weight at 30 flexion  JRF = 2.5- 3 times BW in stair climbing  JRF = 7-8 time BW in squatting Mona Selim  Patellar mal- Patellar mal- tracking alignment Impairment of the It is mal-alignment normal tracking of of forces around the patella inside the patella in the the trochlear groove static position during the range of knee motion. Mona Selim -Can be defined as : an Anterior diffuse dull aching knee pain resulting from physical and biochemical changes in the patellofemoral joint in absence of other pathology. Mona Selim Mona Selim 1. Overuse Multi- 2. Trauma factorial 3. Abnormal forces 4. Thigh muscles imbalance, weakness or tightness 5. Patellar tracking disorder 6. Pes cavus, pes planus 7. Excess weight Mona Selim  Increased Q angle  Tight iliotibial band  Tight vastus lateralis  Vastus medialis oblique insufficiency  Tight hamstring  Tight quadriceps  Patella alta Mona Selim  Increased Q angle 1-Wide pelvis -femoral anteversion squinting patella & external tibial torsion -genu valgum Mona Selim 2-laterally displaced tibial tuberosity. -external tibial rotation -internal femoral rotation -Pronated subtalar joint  weakness of quadriceps mainly vastus medialis obliqus  weakness of the gluteus medius and hip external rotators muscles result in: Increased hip internal rotation  also might increase Q angle through medial displacement of the patella relative to the tibial tubercle (squinting patella). Mona Selim  lateral retinaculum and ilio tibial band(excessive lateral tracking of the patella)   1- Hamstring,?! (more posterior force on the knee & the JRF)  - Quadriceps ?!(increase the JRF)  -Gastronomies(can lead to foot pronation) Mona Selim  Location of the pain Aggravating activities History of the pain, its behavior Other associated symptoms such as giving way or swelling. Patients may complain of the knee giving way. This usually does not represent true patellar instability but rather transient inhibition of the quadriceps because of pain or deconditioning Mona Selim  Signs and symptoms  1-Anterior knee pain (prolonged knee flexion 90 degrees. (positive theater sign)  AGGRAVATED BY PHYSICAL ACTIVITY- Running, jumping, up and dawn stair and squatting 2-Catching, popping or grinding sensation 3-Mild to nil swelling 4-Stiffness 5-The symptoms are usually of gradual onset  The patient is initially examined in standing for assessment of lower extremity alignment.  Of particular interest is femoral position, which is easier to see when the patient has the feet together.  Internal femoral rotation Mona Selim femoral anteversion Enlarged fat pad which indicates that the patient is standing in hyperextension or a “locked back” Mona Selim  Ifthe patient’s symptoms are not provoked in walking, then evaluation of more stressful activities, such as stair climbing, is performed.  If symptoms are still not provoked then squat and one leg squat may be examined and used as a reassessment activity. Mona Selim Mona Selim The patella is grasped in the resting position then translated medially The extent of displacement is described in relation to the width of the patella and measured in quadrants.  Displacement of less than one quadrant medially indicates tightness of the lateral structures.  Displacement of more than three quadrants is considered hypermobile Mona Selim Mona Selim Mona Selim Mona Selim  used to assess for lateral instability  The test is positive when pain or discomfort occurs with lateral translation of the patella. Mona Selim Irritation of the infra patellar fat pad from trauma or overuse.   Often occurs from overuse as the result of repetitive jumping.  Tenderness occurs along the attachment of the tendon to the patella.  irritation of the IT band as it passes over the lateral femoral condyle.  Contributing factors could be tight tensor fasciae latae  Noble compression test  known as housemaid’s knee prolonged kneeling results from or recurrent minor trauma to the anterior knee.  When inflamed there may be restricted motion due to the swelling and pain caused by direct pressure or pressure from the patellar tendon Misused to define the patellar pain !! Represents pathological changes in the articular cartilage of the patella. It denotes fissuring, softening and degeneration of the cartilage due to abnormal stresses. This is merely a pathological diagnosis. Should never be equated with anterior knee pain. Mona Selim  Osteoarthritis may be idiopathic or posttraumatic and is diagnosed by radiographic changes consistent with degeneration.  Osgood-Schlatter’s disease (traction apophysitis of the tibial tuberosity) Mona Selim  Avoid squatting and stair climbing  Strengthening quadriceps (vastus medialis)  Strengthening adductors (VMO originate from adductor magnus)  Stretching hamstrings  Stretching gastrocnemius.  Stretching iliotibial band  Stretching quadriceps  Patellar taping  Proprioception training Mona Selim Mona Selim Mona Selim  Medial glide Mona Selim  Thistechnique will help in reducing the tightness of the ITB that will reduce the lateral pull of the of the patella which will help patella to re-harmony with other forces of balance. Mona Selim Mona Selim Mona Selim Mona Selim  Hamstrings  Quadriceps  Gastrocnemius  ITB Mona Selim Mona Selim Mona Selim - Knee flexors - Knee extensors - Hip adductors the VMO originate from add magnus - Hip external rotators mainly gleutius max as accessory m helping weak knee ex. - We can use both isometric and isokinamatic ex - This can be achieved by the SLR exercises. Mona Selim Mona Selim Mona Selim Mona Selim Mona Selim Mona Selim  To correct flat foot Foot pronation →genu valgus →lateral patellar displacement Mona Selim 1. Stay in shape 2. Stretch before and after exercise 3. Increase training gradually 4. Use proper running gear 5. Use proper running form Mona Selim Mona Selim