MENISCAL INJURIES

Meniscal Injuries

Every knee has two menisci ,one medial and other lateral. They act has shock absorbers. Meniscus is semicircular fibrocartilage disc, triangular section.
Only peripheral rim of meniscus is vascularised.
Meniscal injuries are common. These can occur in sports, vehicular accidents and falls. Medial meniscus , due to relative immobility is more prone to injury than lateral one.
Mechanism of medial meniscal injury is abduction, flexion and internal rotation of femur on tibia. Where as lateral meniscus is injured by abduction, flexion and external rotation. Vertical loading and hyperextension are other two mechanisms that can injure either of meniscus.
Sequential loading can damage other structures.
There is classically described unhappy triad O’Donoghue. It is combined injury of medial meniscus, medial collateral ligament and anterior cruciate ligament.

Clinical features
Patient usually describes injury as twisting of knee. The injury occurs on plated foot. More than often, patient hears a pop. During the acute trauma, there is severe pain, swelling and inability to walk.
After acute episode, patient presents with pain and locking.
Locking is feeling of block with inability to straighten leg. It occurs suddenly and disappears dramatically. Occasional patient presents with giving away due to associated ligamentous injury or quadriceps injury.
Signs
1. Joint line tenderness
2. Effusion

Tests for meniscal tears:
a) Click:
A audible or palpable click in ROM of knee can be felt in meniscal tear. This occurs due to femoral condyle riding over an irregularity.
b) Mc Murry’s test:
The test works on principle that meniscus gets entrapped between condyles. With knee flexed, valgus /varus and rotational stress is given. Knee is slowly extended. Audible or palpable click with pain makes test positive. The test is not confirmatory but often informative.
c) Apley’s Grinding Test:
The test is done in prone position. Knee is flexed at ninety degrees. Examiner hold leg and distracts joint. Pain indicates injury to ligaments. In second stage, examiner compresses the joint. Rotational stress is given at same time. A click or pain suggests meniscal tear.
d) Squat test :
This test consists of making patient squat with foot alternately internally or externally rotated. There will be pain medially or laterally. This will give clue about meniscal tear.

Pathological classification
1) Longitudinal tears
2) Transverse and oblique tears
3) Combination of longitudinal, transverse tears.
4) Associated with cystic menisci
5) Associated with discoid menisci

O’ Connor’s classification
1) Longitudinal tears
2) Horizontal tears
3) Oblique tears:
4) Radial tears.
5) The variations:
a) Flap tears
b) Complex tears contain all elements occurring in old with chronic meniscal lesions or in old degenerative menisci.
c) Degenerative tears.

Management:
Conservative management is first line method. After initial management of RICE. Patient is advised to refrain from hard activities. He is advised rest of part with splint or brace. Elevation of limb is given. NSAIDS are prescribed for pain relief. A protocol physiotherapy program is designed for him.
Conservative method is indicated for stable peripheral tears , incomplete longitudinal tears and radial tears.


Surgical management is preferred in active and young sports man. It can be done either open or arthroscopic. Arthroscopy has advantages of early mobilisation and less tissue reaction. Modalities practiced are menscectomy. Meniscectomy can be partial or subtotal or very rarely total.
In partial Meniscectomy, a stable peripheral rim of healthy meniscal tissue is preserved.
Indications: 1) Loose unstable meniscal fragments
2) Displaceable inner edge in bucket handle tear
In subtotal meniscectomy, excisions of upto peripheral rim is done
Indications:
a) Complex tears
b) Degenerative tears of Posterior horn.
In total meniscectomy, complete removal of meniscus is done.
Indications: a) Meniscus detached from peripheral attachment.
b) Intra meniscal damage
c) Extensive damages.