Knee Conditions
Chapter 15
Anatomy
Large synovial joint
Two condylar articulations
Medial tibiofemoral joint
 Lateral tibiofemoral joint

Gliding joint

Patellofemoral joint
Bones
Femur
Medial epicondyle
 Lateral epicondyle
 Linea aspera

Tibia
Medial tibial plateau
 Lateral tibial plateau

Fibula
Tibiofemoral Joint
Modified hinge joint allowing some
lateral and rotational motions to occur
as well.
Lateral epicondyle is larger than medial.
Because of size difference there is a
screwing home mechanism to bring the
knee into full extension.
Menisci
Semilunar fibrocartilage (half moon shapes)
Attach to the superior plateaus of the tibia.
Absorption and dissipation of force
Lubrication
Medial meniscus is semicircular and attaches
to the medial collateral ligament
Lateral meniscus is almost a complete circle
and attaches to the posterior cruciate
ligament
Bursae
Suprapatellar bursa, lies between the femur
and quadriceps femoris tendon
Subpopliteal bursa, lies between the femur
and the popliteal muscle
Semimembranosus bursa, lies between the
medial head of the gastrocnemius and the
semimembranosus tendon.
Prepatellar bursa, lies between the skin and
the anterior surface of the patella
Bursae continued
Superficial infrapatellar bursa is located
between the skin and the patellar
tendon.
Deep infrapatellar bursa is located
between the tibial tubercle and the
infrapatellar tendon.
Ligaments
Anterior Cruciate Ligament (ACL), attaches
anteriorly on the tibia, and to the posterior
surface of the lateral femoral condyle.
Prevents:




Anterior translation of the tibia on a fixed femur
Posterior translation of the femur on a fixed tibia
Internal and external rotation of the tibia on the
femur
Hyperextension of the tibia
Ligaments continued
Posterior Cruciate Ligament (PCL),
attaches posteriorly to the tibia, and to
the anterior surface of the lateral medial
condyle of the femur.
Prevents:

Posterior displacement of the tibia on a
fixed femur.
Ligaments continued
Medial collateral ligament (MCL)
connects from the medial condyle of the
femur to the medial tibia through the
medial meniscus.
Prevents:
Medially directed shear forces (valgus)
 Rotational forces

Ligaments continued
Lateral collateral ligament (LCL)
connects from the lateral condyle of the
femur to the head of the fibula.
Prevents:
Laterally directed shear forces (Varus)
 External rotation of the tibia

Ligaments continued
Arcuate-popliteal complex composed of the
semimembranosus tendon and the popliteal
ligament connects the lateral condyle of the
femur to the head of the fibula.
Prevents:



Anterior displacement of the tibia relative to the
femur.
Hyperextension of the knee
Hyperflexion of the knee
Patellofemoral joint
Triangular bone (Patella) rests between
the femoral condyle to form the
patellofemoral joint.
Three distinct facets
Increases angle of pull on the patellar
tendon
Glides between the femoral Trochlear
groove
Patellofemoral joint cont.
Greatest compressive forces occur
when the knee is in 30 deg. Of flexion.
Patellar positioning is maintained by:
Lateral retinaculum
 Medial retinaculum
 Medial patellofemoral ligament
 Lateral patellofemoral ligament

Muscles of the Knee
Rectus femoris (ext)
Vastus lateralis (ext)
Vastus intermedius
(ext)
Vastus medialis (ext)
Semitendinosis
(flex)
Semimembranosus
(flx)
Biceps femoris (flex)
Sartorius (flex)
Gracilis (flex)
Popliteus (flex)
Gastrocnemius
(flex)
Plantaris (flex)
Nerves
L4
L5
S1
S2
S3
Kinematics
Flexion primarily carried out by the
hamstrings assisted by gastroc,
popliteus, gracilis, and sartorius.
Secondary responsibility of these
muscles is to rotate the tibia
Extension primarily carried out by the
quadriceps group.
Contusions
Fat Pad Contusion
Peroneal Nerve Contusion
Bursitis
Prepatellar
Deep infrapatellar bursitis
Pes anserine bursitis
Tibial collateral bursitis
Ligamentous Injuries
Straight valgus
Straight varus
Straight anterior
Straight posterior
Anteromedial rotary
Anterolateral rotary
Posteromedial rotary
Posteroladeral rotary
Knee Dislocations
Meniscal Injuries
Longitudinal
Bucket-handle
Horizontal
Parrot-beak
Patellar and Related injuries
Patellofemoral stress syndrome
Chondromalacia Patellae
Patellar Instability and Dislocations
Patella Plica Syndrome
Patellar Tendinitis
Osgood-Schlatter Disease
Sinding-Larsen-Johansson’s Disease
Extensor Tendon Rupture
IT Band Friction Syndrome
Fractures
Avulsion
Epiphyseal and Apophyseal
Tibial Tubercle
Distal Femoral Epiphyseal
Stress Fractures
Chondral and Osteochondral Fractures
Osteochondritis Dissecans
Patellar Fractures