NMS 3: Knee Flashcards
Knee: General Characteristics
-Largest and most complex joint in the body
-All in one capsule
-Tibiofibular: More associated with the ankle and in it’s own capsules
Joints of the Knee
Medial tibiofemoral, lateral tibiofemoral, patellofemoral
What joint is more associated with the ankle and it’s own capsules
Tibiofibular Joint
Functions of the knee
Weight bearing and Locomotion
Knee: Vulnearability to Dysfunction
-Superficial anatomical exposure: No muscles to protect from direct blows
-Large functional demands
Stabilizing Structures of the Knee
-Shape of the articular surfaces
-Interposed medial and lateral meniscus: Support a majority of the weight
-Fibroelastic properties of the capsule
-Protective action of the bursa
-Restrictive effects of the joint ligaments
-Strength of the surroundings muscles: Quads-around the patellar tendon
-Lubricating and cushioning of the fat pads
Knee Flexion
-Tibia slides forward/Femur slides back
-Tibial condyles roll A-P under femoral condyles
-Tibial condyles also glide A-P
Knee Extension
-Tibia is stationary, femur slides back
-Tibial condyles roll P-A under femoral condyles
-Tibial condyles also glide P-A
What happens in the last 10-20 degrees of knee extension
Tibia externally rotates (screw-home mechanism)
Knee-Full Extension
-Tibia externally rotated (screw home)
-Cruciate “uncrossed”
-More resilience on collaterals (taking on most of the force )
-Muscular stabilization by: Pes anserine tendons, ITB, hamstring
Patella: Strucure/Functions
-Medial and lateral facets articulate with the patellar groove of the femur
-Patellar groove and facets cover with articular coverage and lie inside the capsular fibers of the knee joint
-Patella protects from anterior blows
-The more you flex, the more force that is placed into the patella
Patellofemoral Joint Reaction Forces
-Walking: 100 lbs
-Bike: 100lbs
-Deep Squatting: 4000lbs
-Squatting: 1400lbs
-Jogging: 1400lbs
-Stairs descent: 1000lbs
-Stair ascend: 660lbs
Coupled Motions of the Knee
-Flexion and internal rotation
-Extension and external rotation
-Most injuries happen are a result of rotation to the ________side of flexion and extension
Opposite; Plant foot bent knee and turn inward sports and even going down stairs
The knee is very susceptible to injury in the ______ packed position
Open; more impact on the cruciate ligaments, which don’t hold load as well
Suprapatellar Bursa
-Can be continuous with the joint capsule
-Superior aspect of patella upward beneath the quadriceps
-Decreases friction between the quadriceps tendon and femur
-Extension of the synovial membrane (contains fluid)
-Intrasynovial
Prepatellar Bursa
-Subcutaneous anterior to patella
-Protects from blow to patella and from kneeling on the kee
-“Housemaid knee”
-Extracapsular
Superficial Infrapatellar Bursa
-Subcutaneous anterior to patellar tendon below patella
-Inflammation…
Deep Infrapatellar Bursa
-Deep to infrapatellar tendon
-Sometimes continuous with the synovial space
-Increase in the superficial or deep infrapatellar bursa called “Parson’s Knees”
Pes Anserine Bursa
-Lies between MCL/tibia and pes anserine muscles
-Related to runners
Chondromalacia Patella
-Degenerative process that involves softening and fissuring of the patellar articular cartilage
-Very common (Affect 1/3)
-3 categories: Primary Idiopathic, secondary adolescent, adult
Primary Idiopathic
-No trauma, disease, or deformity
-Adolescents and young adults
-Begins on the medial of the patella
Signs/Symptoms of Idiopathic Chondromalacia patella
-Diffuse ache
-pain increased with quadriceps stress
-creptis/catching in the knee
-effusion
-movie sign (prolonged sitting)
Diagnosis of Primary idiopathic
Pain over the margin of the patella
-pain when the patella is “scrambled” across the femur (Perkins sign)
-Pain with direct pressure of the patella on the femur (Fourchet’s sign)
X-Ray Findings: Primary Idiopathic Chondromalacia
-MRI (image of choice)
-Prognosis: Continue for years and may become better or worse
-Most improve spontaneously and do not progress to DJD
Treatment of Primary Idiopathic
-Exercise* :Lateralis stretched/medialis strengthened
-conservative care
-improve the tracking of the patella, align lower leg, adjust the hip, knee, foot and ankle and low back
-Inflammation control
-Nutritional supplements for inflammation and cartilage support
-Align lower leg (pes planus)
Secondary Adolescent Chondromalacia
-Softening of cartilage secondary to trauma
-Adolescents and young adults
-Etiology: Direct or indirect trauma, increased Q angle, elongation of patella tendon, microtrauma
-Signs/symptoms: Lesion is more lateral over lateral aspect of patella, buckling is common
-Treatment: Same as idiopathic
Adult DJD-Patellofemoral Syndrome
-Middle aged and beyond
-Softening of the entire patella, onset usually insidious
-Signs/symptoms: Limitation of motion, effusion, crepitation, pain w/ activity
-Treatment: Same as adolescent (adjust to restore normal tracking)
Osgood Schlatter’s Disease
-One of most common causes of knee pain in active adolescents
-Jumping/cutting sports
-Bilateral in about 20% of cases
-Exact cause is unknown
-enlarged tibial tubercle (where pain is)
-Usually remits on skeletal maturity
-Permenent bump
Grades of OS
- Pain after activity
- Pain during/after activity
- Constant pain
Sinding-Larsen-Johansson Disease
-Located at inferior pull of the patella
-Treatment: Same as OS
Osteoarthritis of the Knee
-The risk of disability from OA Knee is as great as that of CV disease
-One of the most common sites of osteoarthritis
Etiology of Osteoarthritis
-Heredity: genetic mutations
-Weight: increases pressure on joints
-Age
-Gender
-Trauma
-Repetitive Stress Injuries:
-High Impact Sports: Soccer, long-distance running, tennis
-Other Illnesses
Symptoms of OA
-Early: Painful cracking or grinding
-Late: Attacks of synovitis and muscle atrophy of the quadriceps
Treatment of OA
-Mobilize joint
-normalize abnormal stress
-Treat the effusion
-Exercise: Weight loss, strengthen quads, increase circulation
-Anti-inflammatory drugs
-Intra-articular treatments
-Surgery
-Brace
Infrapatellar Bursitis
-Deep and superficial infrapatellar bursitis
-dumbbell shaped
-Parson’s Knees
-The prepatellar bursae is most common (Housemaid’s knee)
IT Band Syndrome
-Most common cause of lateral knee pain in runners
-Friction on distal IT band
-Seen in: long distance runners, weight lifters, cyclists, skiers, x-country runners
Predisposing factors of IT Band Syndrome
-Genu varum, foot problems, leg length discrepancy
Signs/Symptoms of IT Band Syndrome
-Tenderness over the lateral epicondyle
-Usually occurs between miles 1-5
Jumper’s Knee (Patellar Tendinitis)
-Tendititis occuring at the bone tendon junction
-Occurs in athletes requiring explosive quad movements
-Rapid increase in training frequency/intensity
-Improper mechanics
-Training on ridged surface
Signs/Symptoms of Jumpers Knee
-Squeaky Knee
Baker’s Cyst (Popliteal Cyst)
-Synovial herniation in the posterior of the knee
-Causes: Semimembranous/gastroc bursa
Torn Meniscus
-Mostly avascular
-Outermost 20% of the meniscus with blood supply
-Feels “locked”
-Any twisting, squatting or impacting activities
-Meniscal tissue doesn’t heal
-Most times can be treated without surgery
Torn Mesniscus causes
-traumatic tears: twisting injury or a blow to the side of the knee/oftentimes under 30 years old
-Can also be degenerative: Natural drying-out of the inner center
Dislocated Patella
-Lateral
-Patellar groove is shallow
-After dislocation, muscle spasm flexing the knee locking the patella lateral to the groove
Anterior Cruciate Ligament
-Most commonly injured ligament of the knee
-Sports-related
ACL Injury occurence
-More common in women than men
-“loosely” attirbuted to hamstring/quad strength imbalance
-Planting/cutting
Lachman’s Test
-Least stressful/most reliable indicator of ACL tear
-Patient supine with knee in 20-30 degrees of flexion
