2. CONTENTS
Anatomy of menisci
Functions of menisci
Types of menisci
Biomechanics {Screw-home mechanism}
Classification
Mechanism of injury
Predisposing factors
Clinical features
Symptoms
Signs
Investigations and Examination
Differential Diagnosis
Treatment
3. ANATOMY OF MENISCI
• Fibrocartilaginous discs
• Shaped like crescents
• Placed on tibial condyles
Each meniscus has following
• 2 ends- anterior and posterior ends
• 2 borders- outer and inner border
• 2 surfaces- upper & lower surfaces ,
peripheral part and inner part
4. FUNCTIONS OF MENISCI
Stability of joint
Helps in weight transmission
Shock absorber
Increase contact area
Supply nutrition to articular cartilage
Helps in locking mechanism
Assists and controls gliding and sliding motion of knee
Proprioceptive impulses
5. TYPES
Lateral menisci
Medial menisci
a) semicircular
b) wider from behind
c) Posterior fibers of anterior end continuous
with transverse ligament
d) Peripheral margin adherent to deep part of
tibial collateral ligament
6. SCREW-HOME MECHANISM
The "screw-home" mechanism, considered to be a key element to knee stability, is the rotation between the tibia and
femur and occurs at the end of knee extension, between full extension (0
o
) and 20
o
of knee flexion. The tibia rotates
internally during the open chain movements (swing phase) and externally during closed chain movements (stance
phase). External rotation occurs during the terminal degrees of knee extension and results in tightening of both
cruciate ligaments, which locks the knee. The tibia is then in the position of maximal stability with respect to the femur.
7. Injury to the medial meniscus of the knee
The medial meniscal injury is more
common than lateral meniscal injury
because lateral meniscus has:-
small diameter
Thicker periphery
More mobility
Attachment to both cruciate ligaments
Stabilization to femoral condyle by
popliteus
8. CLASSIFICATION
SMILLE’S CLASSIFICATION O’CONNOR CLASSIFICATION
1. LONGITUDNAL TEARS
peripheral attachment tear 10%
complete tears 23%
segmental tear 2%
2. HORIZONTAL TEARS- 48% posterior anterior
and middle
3. CYSTIC DEGENERATION- 2%
4. CONGENITAL ANOMALIES 5%
5. DEGENERATIVE LESIONS
Based on tear pattern found during surgery
A. Longitudinal Tear
B. Radial Tear
C. Horizontal Tear
D. Bucket Handle Tear
E. Parrot Beak Tear
F. Segmental/Flap tear
10. MECHANISM
OF INJURY
Tear of meniscus from periphery and its longitudinal splitting
Excessive force leads to
Trapping of posterior horn in this position by sudden extension of
knee
Posterior segment of medial meniscus is forced towards joint’s
center
Internal Rotation of femur over tibia with knee in flexion
13. SYMPTOMS
• ON INITIAL INJURY
1. Pain on inner side of knee
2. History of locking
3. Swelling over knee
4. Recovery after initial episode
• FURTHER INCIDENTS
1. Knee periodically gives trouble
2. Locking history may or may not be present
3. Unlocking (Pathognomonic)
4. Click
5. Feeling something moving within the joint
6. Pain on inner side of knee
• BETWEEN INCIDENTS
Knee is normal
14. SIGNS
Locking +ve
McMurray’s Test +ve
Apley’s Squat test +ve
Duck Waddle test +ve
Steinmann’s Sign +ve
Helfet Sign +ve
Quadriceps Atrophy +ve
Medial Joint line tenderness +ve
15. EXAMINATION
Test Position: Standing.
Performing the Test:
Have the patient stand on the test leg with the knee
bent to 20 degrees of flexion (the opposite leg is
flexed behind the patient).
The patient may place his/her hands on the hands of
the examiner for balance during the test.
The patient then rotates the knee medially and
laterally 3 times each direction.
A positive test occurs when the patient experiences
joint line discomfort or if locking/catching occurs.
16. Test Position: Sitting.
Performing the Test: With the patient sitting at the
edge of the table and the patient's knees bent 90
degrees, palpate the lateral and medial tibiofemoral
joint line. A positive test occurs when pain is
produced.
17. Test Position: Supine.
Performing the Test:
Place the patient's tested leg in maximal hip and knee
flexion.
While palpating the joint line, apply a valgus force to
the knee, while simultaneously externally rotating and
extending the knee completely.
Place the tested leg back in maximal hip and knee
flexion. While palpating the joint line, apply a varus
force to the knee, while simultaneously internally
rotating and extending the knee completely.
A positive test occurs when pain or clicking/thudding is
produced
18. Test position: prone position with the knee flexed to 90
degrees.
Performing the test:
• The patient's thigh is rooted to the examining table
with the examiner's knee.
• The examiner laterally and medially rotates the tibia,
combined first with distraction, while noting any
excessive movement, restriction or discomfort.
• The process is then repeated using compression
instead of distraction.
• If rotation plus distraction is more painful or shows
increased rotation relative to the normal side, the lesion
is most likely to be ligamentous.
• If the rotation plus compression is more painful or
shows decreased rotation relative to the normal side,
the lesion is most likely to be a meniscus injury.
23. Aim to make rehabilitation programme more effective and faster
recovery.
Measures:-
• Quadriceps exercises during swelling
• Knee swinging for early return of function
• Raised SLR to strengthen knee
• To improve posterior stability of knee resistive exercises of
hamstrings and calf muscles
24. During first
five days
a.Thermotherapy to
reduce pain
b. To reduce
effusion –
quadriceps
exercises, resistive
ankle and foot
exercise,SLR
c. To prevent reflex
inhibition- -
sustained
quadriceps
with 5-10 sec hold
d. Relaxed knee
During 5-15
days
a. Above measures
are made more
vigorous
b. Knee rachet and
pedo cycle regime
c. Ambulation with
supported or full
weight bearing
d. 90 degree knee
movements
During 2-3
weeks
a. 120 degree knee
movements
b. Should be able
stand alone at
unaffected leg
c. PRE to
Quadriceps
d. Floor Squatting ,
Cross leg sitting,
Prone kneeling
e. Ambulation with
minimum or no
During 3-5
weeks
a. Isotonic knee
exercises
b. ART to
quadriceps
c. Balancing to
improve
Proprioception
d. Gait training
e. Patient is
permitted to
resume work
After 6
weeks
Return to sports
and allowed for
jogging,
running,
jumping,
hopping