Anatomy and Biomechanics
What muscle is most important for stabilizing the knee?
The Quads! -> especially vastus lateralis and medialis
MOI of ACL
- Typically non contact from pivoting, cutting, and jumping
- Rapid deceleration injury
- In contact injury lateral valgus force
- Taut in extension
Hamstring MOI and symptoms (include which muscle and hamstring to quad ratio)
Rapid extensive knee contraction of the quads or violent stretch of hamstring muscle. Occurs commonly in terminal swing phase of gait.
Typically the biceps femoris
Imbalance between the quad: hamstring ratio
- Hamis are 60-70% of the strength of the quad
SxS: sprinting running, posterior thigh pain, audible pop, pain with sitting
MOI: Traumatic valgus or tibial lateral rotation (medial meniscus) and varus or tibial medial rotation (lateral meniscus). Twisting injury.
Presentation: catching, locking, pain with forced hyperextension, delayed effesuion, TTP of joint line
Prognosis: Outside meniscus more vascularized better prognosis medial meniscus no blood flow so poor prognosis
Ottawa Knee Rules
1 or more for acute injury get X-ray!
1. Age > 55
2. Tenderness at the head of the fibula
3. Isolated tenderness of the patella during palpation
4. Inability to flex the knee to 90 degrees
5. Inability to bear weight immediately and upon ER evaluation
Structures in the Extracapsular Knee
patellar ligament, LCL, MCL, oblique popliteal ligament, arcuate popliteal ligament, patellar retinaculum
MOI of PCL
- Posterior translation of tibia
- Typically anterior blow to the tibia (MVA or sports)
Patellar Tendinopathy and Quads Tendinopathy MOI
Patellar: Jumpers knee! Overuse injury
- Young men, high repetitive loads, lower quad strength, pain on inferior pole of patella
Quadriceps: loading
- Pain at superior pole, pain when loading, ceases when load is removed
What are Articular Cartilage Defects (ACD) and what causes them?
Articular Cartilage Defects (ACD) refer to damage or irregularities in the smooth, protective cartilage that covers the ends of bones in a joint. These defects can result from a variety of factors, including traumatic injuries, repetitive overuse, or degenerative conditions like osteoarthritis. ACD can lead to joint pain, stiffness, and reduced range of motion.
Effusion vs swelling
Effusion
Intracapsular - ACL, PCL, and meniscus
Stroke test
troke up on the medial side of the knee and observe if liquid flows back down spontaneously. If it doesn't stroke downward on distal lateral thigh and see if the liquid returns from before "milking"
Swelling
Extracapsular - LCL/ MCL
Girth measurements
Look at dimples
Intracapsular structures in Knee
ACL, PCL, M/L meniscus
MCL and LCL MOI
- Valgus stress on planted leg
- Typically contact injury
LCL
- Varus force
- Not very common
Tendon Rupture MOI and clinical presentation
- Very Uncommon
MOI: Sudden quadriceps contraction on a flexed knee
Clinical presentation: gradual onset, palpable gap, can't extend knee, worse with larger load
OA MOI, pain cycle, and prognosis
MOI: Hyaline articular cartilage is thinning
Valgus -> worse pressure on the lateral side and Varus -> worse pressure on the medial side
Pain: medial knee during WB, muscle weakness, joint stiffness in morning, impaired balance
Prognosis: chronic irreversible disease but PTs can improve pain, functional outcomes, and QoL because recreation exercise helps!
What are osteochondral defects
Osteochondral Defect - defect/disruption that affect the bone and articular cartilage
Osteochondritis dissecans - bone and cartilage detach from the underlying bone
Typically occurs on lateral aspect of medial condyle
defect attaches bone cartilage/detachment from underlying bone that can result in loose bodies we THINK caused by repetitive microtrauma
What moves in open chain flexion/ extension?
concave on convex or convex on concave?
Concave (tibia) moving on convex (femur)
Roll and slide in the same direction
Concave tibial plateaus slide in the same directions
Flexion - tibia rolls and slides posteriorly
Extension - tibial rolls and slides anterior on femur
Structures:
LCL
Popliteus tendon
Popliteofibular ligaments
MOI -> contact in posterolateral directed force -> causes hyperextension and varus
IT Band friction syndrome MOI and Presentation
Presentation: gradual onset, lateral knee pain, TTP at gerdys.
Aggs: running inclines and climbing stairs
Patellofemoral pain syndrome MOI, Aggs, and Risk factirs
Common in adolescents
Pain from: stairs, prolonged sitting, squatting, rising from chair, jumping and running
Risk factors: weak hip extensors, abductors, ER, and quads. Single sport activity, abnormal patellar tracking
Tendinopathy vs tendonitis
When is Jamie Palermo's 27th (yikes) birthday?
tendinopathy: chronic tendon pain and loss of function related to mechanical loading
tendonitis: acute inflammatory process
Sunday February 11th
What moves in close chain flexion/ extension?
concave on convex or convex on concave?
Convex (femur) moving on concave (tibia)
Move in opposite direction
Flexion - tibia slides anteriorly femur rolls posteriorly
Extension - tibia slides posteriorly femur rolls anteriorly
Patellofemoral Instability epidemiology, MOI, and treatment
Caused by lateral resultant force of the quad typically in adolescence.
MOI: Direct trauma and force quad contraction with susceptible joint
Treatment: taping
Test with apprehension and reproduction
+ test will be apprehension/quad contraction w lateral force AND no apprehension/quad contraction w medial
Presentation: loss of function of quads, loss of knee flexion ROM, progressive thigh stiffness, pain with walking
Fat fat fattie pad syndrome symptoms
Gradual onset, catching, stairs and incline pain, TTP at medial femoral condyle, clicking and popping
Time of Blakelyn Elisabeth Palmer's Birth
10:26 AM