Knee/Leg Flashcards
Label the Diagram Below
Which femoral condyle is larger?
Medial
- Creates “rollback” and ER on lateral condyle in flexion
What are the shapes of the medial and lateral tibial plateau? Which plateau is more distal?
- Medial - golf tee
- Lies more distal because proximal tibia is in 2-3 degrees varus
- Lateral - more proximal, shaped like hockey stick
What is the posterior tibial slope?
8-10 degrees
Types of trochlear grooves (4)
- Shallow Trochlea (>145 degrees)
- Flat Trochlea
- Medial Condyle Hypoplasia
- “Cliff”
*clinical relevance in risk factors for patellar instability
What are the deforming forces in the proximal tibia?
- Deformity is procurvatum & valgus
- Procurvatum
- Extensor Mechanism
- Gastrocs
- Valgus
- Pes
What is the average patellar thickness? What is the thinnest you can cut it in a patellar resurfacing?
- Average 23-25mm
- Do not cut to <12mm - associated with increased risk of fracture
How many facets does the patella have?
Seven (3 medial, 3 lateral, 1 odd facet)
Where do you normally see a bipartate patella?
Superolateral pole
Seen in 2% of population
What is the TT-TG and what is its clinical relevance?
- Distance between tibial tuberosity and deepest part of trochlear groove.
- <15mm = normal
- 15-20 = at risk
- >20mm = abnormal
- Increased risk of patellar instability with higher TT-TG value
What is the mechanical axis?
- Line from the centre of the femoral head ot the center of the distal tibial plafond
- Femur 3 degrees valgus from vertical axis
- Tibia 3 degrees varus from vertical axis
What is the anatomic axis of the lower limbs?
- Line down the center of the long axis of the femur and tibia
- Femur - anatomic axis 6 degrees valgus from mechanical axis, 9 degrees valgus from vertical
- Tibia - mechancial axis = anatomic axis = 3 degrees varus from vertical
What is the Lateral Distal Femoral Angle?
81 Degrees
What is the Lateral Proximal Tibial Angle?
93 degrees
What do you have to do, to ensure even flexion and extension gaps when performing your femoral cuts?
- Need to rotate your femoral cutting guide 3 degrees to account for the 3 degrees of external rotation of the posterior condyles
- This makes it paralell to the tibial cut at 0 degrees.
How do you draw the Q Angle? What is normal for males and females?
- Angle between:
- Line from ASIS to centre of patella
- Line from centre of patella to tibial tuberosity.
- Normal:
- Males - 14 degrees
- Female - 17 degrees
What are the ligaments of the proximal tibiofibular joint?
- Anterior ligament of the fibular head
- Posterior ligament of the fibular head
What kind of joint is the proximal tib/fib joint?
Plane/Slinding Joint
What are the ligaments of the Anterior Knee?
Retinacular Ligaments:
- Medial and Lateral Transverse Patellar Ligaments
- Medial and Latearl Longitudinal Patellar Ligments
List the Layers of the Lateral Knee
- Superficial Layer
- Anterior ITB
- Posterior Biceps Femoris
- Middle Layer
- Patellar Retinaculum
- Deep Layer
- Superficial Deep Layer
- LCL
- Patellofibular Ligament
- ALL
- Deep Deep Layer
- Lateral joint capsule
- Popliteofibular Ligament
- Popliteus Tendon
- Arcuate Ligament
- Superficial Deep Layer
Components of the Posteriolateral Corner
PAPP Loves Immature Litle Blondes
Popliteus
Arcuate Ligament
Posterolateral Capsule
Popliteofibular Ligament
LCL
ITB
Lateral Head of Gastrocs
Biceps Femoris
Describe the Dial Test
- Have patient with knees together.
- Test ER at 30 degrees and 90 degrees
- If >10 degrees difference at 30 degrees alone = PLC injury
- If >10 degrees difference at 30 & 90 degrees = PLC & PCL injury
In the Laprade technique for PLC reconstruction, which structures are reconstructed?
- LCL
- Popliteofibular Ligament
- Popliteus Tendon
In which % of PLC injuries is there a concomittant peroneal nerve injury?
13%
What is the most anterior structure on the fibular head?
- The LCL. Biceps Femoris attaches posteriorly.
What is the origin and insertion of the LCL?
- Origin- Lateral Epicondyle
- Insertion- Fibular Head
Describe the Layers of the Medial Knee
-
Superficial:
- Anterior: medial patellar retinaculum from vastus medialis
- Middle: deep fascia of the thigh around sartorius
- Deep: Deep fascia of the thigh around gastrocs and roof of popliteal fascia
-
Middle:
- Anterior: MPFL
- Middle: Superficial MCL
- Deep: Semimembranosus
-
Deep:
- Joint Capsule
- Deep MCL - attached to medial meniscus
Between which layers of the medial knee does the pes lie?
Between Layers 1 &2
Where does the saphenous nerve and short saphenous vein lay in relation to the pes?
Just posterior to the pes insertion.
List the pes anserinus tendons from superficial to deep.
- Sartorius
- Gracilis
- Semimembranosis
- Semitendonosis