knee joint clinical anatomy

1. KNEE JOINT
ANATOMY & APPLIED ASPECTS
Dr. Shyam sunder sharma
Dept. of PMR
SMS Medical College, Jaipur

2. THE JOINT ANATOMY
Consists of two joints
• PATELLOFEMORAL JOINT
• TIBIOFEMORAL JOINT
 Bicondylar diarthrodial modified
hinge synovial joint
 Complex because of function of
joint mobility as well as joint
stability. No inherent stability,
dependent on soft tissue-
supporting structures
 Joint surrounded by capsule and
ligaments richly innervated by pain
fibres and extremely sensitive to
pain and stretch
 Synovial membrane poorly
innervated

3. • TIBIOFEMORAL JOINT • PATELLOFEMORAL JOINT

4. PATELLOFEMORAL ARTICULATION
• Between patellar surface of
femur and posterior surface
of patella
• Posterior smooth surface
has larger lateral part and
smaller medial part,
• Quadriceps tendon plus
patella plus patellar tendon
Commonly referred as
extensor mechanism
• Increase mechanical
leverage of quadriceps

5. Patelofemoral joint

6. Tibiofemoral joint
• Femoral and tibial condyles
• Medial obliquity of the shaft of the femur
• Medial condyles larger
• Lateral femoral condyle shifted anterior
• Two condyles separated through
intercondylar notch except anteriorly by
patellar sulcus engages patella during
early flexion
• Femoral condyles sit on relatively flat
tibial condyles
• Two tibial condyles separated via
intercondylar tubercles engages with
intercondylar notch during extension
• Because of lack of bony stability acessory
structures are important for joint
congruency

7. Menisci
• Convert tibial plateau into
concavities for the femoral
condyles
• Allow axial loads to be
dispersed in radial directions
• Contact area is decreased
and joint stress reduced
• Strong attachments of
menisci prevent squeezing
out of the tibiofemoral joint
during compression

8. Meniscal attachements
• Open ends called horns which
are attached to tibia
• To tibial condyles at periphery
bt coronary ligaments
• To each other by transverse
ligament anteriorly
• Medial meniscus attached to
joint capsule through medial
thickening from femur to tibia
called medial collateral
ligament.
• Medial meniscus also attached
to ACL & PCL.

9. Menisci
MEDIAL MENISCUS
• Semilunar (less circular)
• Larger
• Covers 65% of articular
surface
• Entire periphery attached to
capsule
• Attached to medial
collateral ligament
• Less mobile
• More prone to injury
LATERAL MENISCUS
• Three fourth of circle
• Smaller
• Covers more percentage of
small articular surface
• Entire periphery not
attached
• Not attached to LCL
• More mobile
• Less prone to injury

10. Ligaments and tendons supporting
knee joint
• Major stabilisers are muscles more than ligaments and
among ligaments collateral and cruciate ligaments
• Lateral support– from superficial to deep illiotibial tract
and biceps femoris tendon, quadriceps
retinaculum,lateral collateral ligament and proximal and
distal patellofemoral ligament,lateral joint capsule
• Medial support-MCL, medial patellar retinacula, tendons
of sartorius,gracillis and smitendinosus, expansion from
semimembranosus tendon
• Posterior support- Arcuate ligament, oblique popliteal
ligament, popliteus, gastrocnemius
• Anterior- Quadriceps patella and patellar tendon,
anterior cruciate ligament

11. LIGAMENTS

13. Cruciate ligaments
• Major stabilliser of knee.
Provides lateral stabillity
and limits anterolateral
rotation of tibia on femur.
• From lateral femur, travels
anteromedially to tibia
• Injured by occurrence of
excessive movements which
it limits.
• Walking downhill becomes
difficult.
• ACL • PCL
• Limits backward glide of
tibia on. Prevents
hyperextension.
• From medial femur travels
posterolaterally to tibia
• Classically injured by high
velocity trauma with
posterior dislocation of
tibia on a flexed knee as in
a dashboard impact in car.

14. ACL & PCL

16. LCL AND MCL
• MCL
• Flat band and is attached
to femoral condyle and
medial surface of shaft of
tibia
• Firmly attached to the
edge of medial meniscus
• Forced abduction of tibia
on femur can result in
tear at its attachments
causing pain at the same
• LCL
• Cordlike and attached to
femoral condyle and head
of tibia
• Tendom of popliteus
intervenes between
ligament and meniscus
• Forced adduction of tibia
on femur can cause injury
• Less common than mcl
injury

17. Posterior Ligaments
• Oblique popliteal ligament-
tendinous expansion derived
from the semimembranosus
muscle. It strengthens
posterior aspect of capsule
• Arcuate popliteal ligament- y
shaped thickening of the
posterolateral capsule arising
from fibular styloid and has
two limbs. Medial limb joins
oblique popliteal ligament and
lateral limb blend with capsule
near gastrocnemius tendon

18. THE JOINT CAPSULE
• The joint capsule that encloses both knee joints is
large and lax. Has a thicker fibrous outer layer and
thinner deep synovial membrane
• Attached to the margins of articular surface and
surrounds sides and posterior aspect of joint
• Has thickenings on sides which we call medial and
lateral collateral ligaments

19. The synovial membrane
• On all expects execpt
anterosuperiorly synovial mebrane
lining is located at the cartilaginous
margin.
• Synovium extends proximally as
suprapatellar bursa
• Infrapatellar pad inserted between
patella and two membranes
• At the back of the joint, prolonged on
deep surface of popliteus tendon
forming popliteal bursa
• A bursa interposed bw med head of
gastrocnemius and medial femoral
condyle & semimembranosus tendon
called semimembranosus bursa
•

20. Bursae
• Prepatellar- between patella and skin
• Suprapatellar-between femur and
quadriceps tendon
• Infrapatellar superficial-between
tibial tuberosity and skin
• Deep infrapatellar-between tibia and
ligamentum patellae
• Pes anserine
• Posterior bursae
• Popliteal bursa
• Semimembranosus bursa
• Bursae related to biceps femoris
tendon, tendons of sartorius, gracillis
and semintendinosus, lateral and
medial heads of gastrocnemius

21. MUSCLES
• FLEXORS (muscles on
anterior)
• Biceps femoris
• Semitendinosus
• Semimembranosus
• Popliteus
• Sartorius
• Gracillis
• INTERNAL ROTATORS
• Popliteus
• Gracillis
• SM,ST
• Sartorius
• EXTENSORS- (muscles on
posterior- hamstrings
mainly)
• Rectus femoris
• Vastus medialis
• Vastus lateralis and
• Vastus intermedius
• Tensor fascia lata
• EXTERNAL ROTATORS
• Biceps femoris

22. Locking and unlocking
• LOCKING- the joint
cannot be flexed unless
reverse rotated when
tibia is laterally rotated
and femur medially
rotated produced by
biceps femoris-the only
lateral rotator of tibia
• Unlocking- reverse of
locking done by popliteus
mainly and assisted by
other medial rotators

23. Muscles

32. Blood supply of the knee joint
Branches from
• Femoral
artery
• Popliteal
artery
• Anterior
tibial artery
• Posterior
tibial artery

33. Nerve supply of the knee joint
• Femoral nerve-gives twigs from the nerve to vasti
• Tibial nerve- gives superior medial genicular,
inferior medial genicular and medial genicular
nerves
• Common peroneal- gives superior lateral
genicular, inferior lateral genicular and recurrent
genicular nerves
• Obturator nerve-gives genicular branch from the
posterior division

34. Popliteal fossa
Superolaterally bounded by
Biceps femoris
Superomedially bounded by
semimebranosus
Inferolaterally and Inferomedially
bound by
Lateral and medial heads of
gastrocnemius
Contents
Popliteal artery
Popliteal vein
Sciatic nerve dividing into tibial and
common peroneal nerve

36. MECHANISM OF INJURY
– VARUS--------LCL
– VALGUS -----MCL
– BACKWARD ----PCL
– ANTERIOR-----ACL
– TWISTING -------
menisci
– VALGUS+FLEXION+T
WISTING--------
MCL>>>ACL>>>MENI
SCI.

37. MENISCAL INJURY
• Shear force from femur
• Acute or degenerative
• Athletes, elderly or
overweight
• Horizontal within
substance
• Longitudinal bucket
handle
• Radial or vertical-
parrots beak

38. Meniscal injury
Medial meniscus injury
• Internal rotation of femur over tibia
with knee in flexion. (Squatting)
• Commonest type of medial
meniscal injury in young adults is
bucket handle tear. This is vertical
longitudinal tear that is incomplete.
• Inner avascular meniscus once torn
does not heal and requires removal
of torn part.
• Symptoms include joint line
pain,catching, popping and giving
away (instability). Deep squatting
and duck walking are usually
painful.
Lateral meniscus injury
• Vigorous external rotation of femur
with knee flexed or during sudden
extension of knee.
• Often more painful
• More liklely to incur-radial or
parrots beak
• Less commonly injured because
lateral meniscus firmly attached to
popliteus muscle and ligament of
wrisburg or of humphry follows
lateral condyle during rotation
• In addition popliteus draws post
segment backward preventing it
from getting caught bw condyles
and pleateau

39. Meniscal injury
Medial meniscal tear Lateral meniscal tear

40. CRUCIATE LIGAMENT INJURY
• ACL injury
• Most comon knee injury
among athletes
• AM fibres taut in flexion
check anterior
displacement
• Hyperextension internal
rotaion rarely isolated
from contact force
• PCL INJURY
• Broader longer and
stronger
• PM AL fibre bundles
• Receives better
vasculature
• Checks post displacement
• Tears less frequent
• Only in isolation when
dashboard injury
• Falling to ground with
foot plantar flexed

41. Cruciate ligament injury

42. Collateral ligament injury
• MCL INJURY
• Attached to fibrous
capsule and mm
• Injury rarely isolated-
unhappy triad
• Can tear with external
rotation with skiing but
more commonly from
valgus or adduction force
football
• LCL INJURY
• Courses slightly posterior-
adduction force rare, BF,
popliteus, IT tract
• Flexed knee= isolated tear
• Anteromedial blow-
posterolateral corner
injury
• Risk to common peroneal
nerve

43. Collateral ligament injury

44. THE UNHAPPY TRIAD
• The most common mechanism
of ligament disruption of knee
is abduction, flexion and
internal rotation of femur on
tibia when foot is planted
solidly on ground and leg is
twisted by rotating body.
• MCL and medial capsular
ligament first to fail followed
by ACL tear if force is of
significant magnitude. The
medial meniscus may be
trapped between condyles and
have a peripheral tear, thus
producing unhappy triad of
O’Donoghue.

45. PATELLOFEMORAL PAIN
SYNDROME/runners knee
• Extensor mechanism malalignment,
with or without an instability syndrome
cartilage under the kneecap is injured
due to injury or overuse
• In overuse injury with extreme and or
repetitive loading of patellofemoral
joint (knee flexion, running, jumping)
• Anterior knee pain (often worse with
sitting in tight space with knee flexed/on
descending slope or stairs or kneeling
down), Mild swelling (maybe B/L)
• Crepitation about patella on ROM
• Tenderness to palpation around patella
• Same as for subluxation, maybe normal

46. PATELLAR TENDINITIS JUMPER’s KNEE
• Excessive jumping or
bounding or high
patellofemoral stress
activity, less commonly
from running
• Infrapatellar pain , originally
after exercise  later while
excersising and at rest
• Rupture with forceful knee
flexion against resistance
• Findings of extensor
mechanism malalignment
Hamstrings, heel cord

47. SYNOVIAL PLICA
• Synovial membrane lined folds which
become problematic when they are
irritated or inflamed
• Most commonly medial plica
• Overuse with repetitive flexion and
extension (running)
• Direct blow to medial patellofemoral joint
(falling on turf/dashboard injury)
• Congenital presence of plica, Other
extensor mechanism malalignment
predisposition may increase likelihood
symptoms because of plica
• Anterior knee pain, pain over supre-
patellar or medial peripatellar regions
with long periods of knee flexion, painful
catching episodes over medial patella
femoral joint

48. OSGOOD SCHLATTER’s KNEE
• Inflamed tibial tuberosity
• Overuse in normal childhood
activities (sports)
• PREDISPOSING – Patella alta,
other evidence of extensor
mechanism malalignment, tight
hams, heel cord, quads
• Painful enlargement of tibial
tuberosity
stigmata of extensor mechanism
malalignment esp patella alta, tight
hams, heel cord, quad
•Enlargement and irregularity of
tibial tuberosity, loose ossicle
separated from tuberosity
patella alta

49. QUADRICEPS TENDINTIS
• Quadriceps tendinitis (including VL
tendinitis and VMO tendinitis) and rupture =
inflammation of quad tendon at its insertion
into superior edge of patella/may involve SL
pole/ SM pole
• Same as for patellar tendinitis
• Excessive jumping or bounding or high
patellofemoral stress activity, less commony
from running
• PREDISPOSING FACTORS –extensor
mechanism disorder
• Suprapatellar pain
• Tenderness at sup pole of patella = central
rectus femoris insertion / Superolateral VL
insertion / Supero medial VMO insertion
• tight hams, heel cord, quads
• Ussually no findings on xray, but there may
be patella baja on rupture

50. BURSITIS
• Usually overuse, because of friction
between skin and patella irritates the
bursa maybe due to direct blow with
bleeding into bursa most comonly
affected are infrapatellar, prepatellar
and pes anserine
• Prepatellar bursitis housemaids knee
• Infrapatellar bursitis clergymans knee
• pes anserinus bursistis – tight
hamstrings seem to predispose
medial knee pain on climbing upstairs
and contracting hamstrings,
• Complaints of swelling ( if preptellar
bursa), pain in respective regions
• For prepatellar bursitis – look for
localized swelling and teNderness, for
others- tenderness over described
areas bursistis)

52. Synovial Osteochondromatosis
• Most common site is knee
joint
• Formation of metaplastic and
multiple foci if hyaline
cartilage in the intimal layer of
synovial joint, bursae or
tendon sheath
• 30-50 year old patients with
dull ache, swelling, stiffness,
transient locking episode and
grating sensations
• Characteristic apppearance of
joint full of cartilaginous
bodies produces snow storm
appearnce

53. POPLITEAL CYST
• popliteal ganglion / Baker’s cyst /
meniscus cyst – fluid filled lesion
arising as flow of synovial fluid
from knee joint into normal
bursa e.g. Gastrocnemius-
semitendinosus bursa resulting
in its expansion or into soft
tissue surrounding knee
• No specific injury from almost any
form of arthritis or cartilage tear
• Localized swelling in popliteal
space or over meniscus posterior
to medial femoral condyle
• MRI helpful in delineating cyst
and ultrasonography

54. Osteochondritis dissecans
• poorly understood disorder which
leads to softening and separation of a
portion of joint surface, resulting in
development of small fragment of
necrotic bone in joint, most common
cause of loose bodies
• Knee lower lateral part of medial
femoral condyle is most commonly
affected
• Trauma single impact or repeated
microtrauma
• Adolescent male with intermittent
ache and swelling
• Localised tenderness and wilsons sign
• Best x ray is intercondylar

55. ILLIOTIBIAL BAND FRICTION
SYNDROME
• Overuse, most cases caused by
running seen in cyclists and
runners
• Site of friction lateral condyle
sharp pain on squatting at 45
degrees
• PREDISPOSING – varus alignment
of knee, running on sloped
surface
• Lateral knee pain on activity
usually popping
• Tenderness over lateral femoral
epicondyle
• Tight ITB
• Absence of intra articular findings

56. THANK YOU