Department of Podiatry

Knee Joint Anatomy and Examination

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These lecture notes are in two sections: anatomy of the knee joint, and examination of the knee joint (including the effect of foot motion on knee function).

Anatomy of the Knee Joint

Anterior Cruciate Ligament (ACL)

runs posteriorly and superiorly from the front of the tibial plateau to its femoral attachment at the posterolateral aspect of the intercondylar notch

prevents forward movement of the tibia in relation to the femur and helps control rotational movement

is essential for pivotal movements

Posterior Cruciate Ligament (PCL)

runs anterosuperiorly from the posterior part of the tibial plateau to its femoral attachment at the medial aspect of the intercondylar notch

prevents the femur from sliding forwards off the tibial plateau

Medial Collateral Ligament (MCL)

provides medial stability

originates from the medial epicondyle of the femur approx. 3 cm above the joint line and passes downward as a thickened band to attach to the anteromedial aspect of the tibia, also has an attachment to the medial meniscus

injured with a valgus stress

Eg. Football, running/jumping sports

Unable to continue playing

Knee swells up rapidly (1-2hrs), v. painful

Lateral Collateral Ligament (LCL)

provides lateral stability

'cord like', 'ropey'

Easy to palpate sitting cross-legged

arises from the lateral epicondyle of the lateral border of the femur and passes downwards to attach to the head of the fibula

injured during a varus stress

Very rarely injured

Menisci

medial and lateral

intra-articular

attach to the tibial plateaus

absorb some of the force placed through the knee

protects articular cartilage

helps stabilise the knee

contributes to lubrication & nutrition of KJ (esp. avascular cartilage)

Patellofemoral joint

quadriceps insert superiorly

inferiorly the patella tendon inserts into the tibial tuberosity

medial and lateral patella retinaculum stabilise

often injured via poor biomechanics whereby the patella tracks poorly in the patellofemoral joint

lateral tracking can lead to chondromalacia patellae (softening of patellar cartilage), not always symptomatic, subluxation, dislocation

decreased VMO strength

patella position , tilt, rotation, displacement

an increase in the Q-angle (>15 degrees)?

excessive subtalar joint pronation, causing a valgus displacement of the knee?

Examination of the Knee Joint

Observation

Need to adequately expose both knees

Must have proper examination table

Stance:

eg. g.varum/valgum/recurvatum,

Baker's cyst

Posterior protrusion of the synovial membrane, seen as popliteal swelling prone and in stance

Spontaneous, sometimes associated with RA

Cruciate Ligaments

1. anterior drawer sign

2. posterior drawer sign

3. Lachman test

4. pivot shift test

5. posterior sag test

Anterior & Posterior Drawer Sign

knee at 90 degrees flexion

patient's foot kept stable

hamstrings need to be relaxed

tibia drawn anteriorly to test ACL

pushed posteriorly for PCL

assess extent of movement and quality of end point

Reproduce any pain?

Increasingly firm pull

Pain/ROM/QOM

Compare L to R

Greater than or equal to 0.5cm displacement = Ruptured ACL

Lachman Test

follows ACL and PCL test

More sensitive than, pt. Less able to contract hamstrings

flex knee to 30°, grasp proximal tibia and support distal femur

Size of pt./practitioner - assistant/pillows?

tibia then pulled anteriorly

note difference in translation and the presence or absence of a firm end point

when uninjured the ligament should have a crisp end point as it stops forward progression of the tibia

complete rupture of the ligament results in a notable (>4mm) increase in translation & an absence of a firm end point

if there is an increase in translation and an end point, then a partial rupture of the ACL or an injury to the PCL should be considered

Pivot Shift Test

helps detect ACL injuries and anterolateral rotatory instability

Place patient on their side

internally rotate tibia

with knee in full extension

valgus force applied to knee

in ACL deficient knee the condyles will be subluxed

then patient's knee is flexed, looking for a 'clunk' of reduction, rendering the test positive

Posterior Sag

PCL rupture test

thigh muscles need to be relaxed

patient supine

flex knees to 90 degrees, hold heel

when a PCL tear is present the tibia may sag posteriorly

Collateral Ligaments

knee fully extended and at 30 degrees of flexion to relax posterior knee capsule

Extended +ve = MCL & cruciate damage

Flexed +ve = MCL damage only

apply a varus (LCL) and a valgus (MCL) force

do not allow the femur to rotate

assess for pain, extent of movement and a feel for an end point

M. spasm can mask a low-grade tear

Best if tested shortly after injury

Menisci

1. Apley Compression Test

2. McMurray's Test

Meniscal injury

Rotational force

Accompanied by a 'pop' sometimes

Often able to continue activity (unlike most other ligamentous injuries

Swelling development in area

Sometimes unable to fully 'lock' the knee in extension - due to bits of torn meniscus

Apley Compression Test

prone

knee flexed to 90 degrees

push down on foot

Int/ext rotate the tib

Like a 'pepper grinder'

places pressure on to the posterior half of the menisci

pain if a tear(s) are present

McMurray's Test

WARNING! Never on acutely painful knee

tests for tears in the anterior half of the meniscus (tests posterior as well)

Patient supine

hip and knee flexed

at various stages of moving the hip and knee from flexion to extension, internal and external rotation of the tibia on the femur is performed

can add varus and valgus stress

pain and a palpable 'clunk' is a positive McMurray's test

if no 'clunk' but pain is present, the meniscus may be damaged or have patellofemoral joint pathology

Patellofemoral joint syndrome

Also called: anterior knee pain syndrome, overutilization syndrome

Gradual onset of pain around the patella

Incidence: high in:

Young athletic individuals

Obese adolescent females

Observation

standing (biomechanics)- patellar position?

lying supine

Swelling - inf/sup, med/lat to patella?

Palpation

tenderness -- where?

Warmth?

tight lateral retinaculum

move medially, laterally, inferiorly and superiorly and check for pain and crepitus

active movement with quad. contraction

apprehension test

Isn't particularly good test

Lots of false positives

Patella position

displacement

tilt

rotation

McConnell, Aust. J. Physio., 1986

McConnel taping

Tape patella medially

Effectiveness?

Psychological/proprioceptive effect?

(Shelton & Thigpen, JOSPT, 1991)

Q-angle

alignment (Q-angle ideally, 15°)

angle formed by two lines: 1: ASIS - bisection of the patella, 2: bisection of the patella - bisection of the tibial tuberosity

pelvic instability, anterior and lateral

excessive subtalar joint pronation?

Reliability?

Validity?

Muscle function

VMO strength and timing

Functional tests

squats, stairs etc.

How does the foot (and foot orthoses) affect the knee?

Historical answer:

foot orthoses decelerate and limit the magnitude of rearfoot pronation which, in turn, decelerates and limits the magnitude of internal tibial and internal femoral rotation

What are some of the problems?

Overemphasis on Q-angle and relationship to patellar tracking

'Screw home' or locking mechanism of the KJ doesn't exist (La Fortune, 1990)

Increased joint reaction force?

Increased valgus force on the knee?

See Sims & Cavanagh (from Jahss, 1991) in manual

Further research?

External markers are not indicative of bony motion in measuring knee rotation (except flex/ext) (Reinschmidt, unpublished thesis, 1996)

Jt. Compressive forces (eg. In PFJ)

There may not be a corresponding large change in the rotational movements of the tibia

But...

It certainly does somehow. For example:

102 patients

Chondromalacia patellae

PF pain/syndrome

Effectiveness of orthoses

76% improvement in symptomology

(Saxena, Amol and Haddad, 1998)

Kevin Kirby's final word...

"It sounds like another theoretical discussion which no-one will win until better research is carried out. Until that time, I know foot orthoses have helped many of my patients with their knee pain"

(Podiatry mailbase, July 21st, 1998)

Summary

Need to be aware of different knee testing procedures for different structures

eg. Cruciate ligaments, Menisci, Collateral ligaments, PFJ

How does the foot affect the knee?

Historical understanding

What further research needs to be done

 

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To learn more about ilio-tibial band syndrome, click the link.

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References

Altchek DW (1993) Diagnosing acute knee injuries - the office exam. Physician and Sports Medicine 21(7): 85-96.

Bartold SJ (1983) A review of patello-femoral syndrome - chondromalacia patella - its importance to the podiatrist. Australian Podiatrist December, 6-9.

Brukner P and Khan K (1993) Clinical Sports Medicine. McGraw Hill, Sydney.

Levy M and Smith A (1994) Diagnosing meniscus injuries - focus on the office exam. Physician and Sports Medicine 22(5): 47-54.

McConnell J (1986) The management of chondromalacia patella - a long term solution. Australian Journal of Physiotherapy 32(4): 215-249.

Tiberio D (1987) The effect of excessive subtalar joint pronation on patello-femoral mechanics - a theoretical model. Journal of Orthopedic and Sports Physical Therapy 9: 160-165.

For a very detailed, beautifully illustrated summary of knee joint examination, follow the link to the MedNet knee pages.

Content Approved by: Head of Podiatry
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Last Updated: August 20th, 2002