ACL tests includes – Lachman, Anterior drawer, Mcintosh(Pivot-Shift), Single leg hopping, Hughson jerk tests. Positive and Negative tests findings :
- Lachman test
- Anterior drawer chest
- Mcintosh chest
- Single leg hopping test
- Hughson jerk test
I. Lachman test :
1. Purpose :
- This test is used to assess individuals suspected of having an anterior cruciate ligament (ACL) damage.
- The test is considered the most sensitive and specific diagnostic for identifying acute ACL injury since it relies on precise placement and technique.
2. Procedure :
- The patient is said to lie-down in supine position with the knee flexed in 20-30 degree.
- The examiner then stabilises the distal femur with one hand while grasping the proximal tibia with the other.
- The proximal tibia is then subjected to an anterior force in an attempt to sublux the tibia forward while keeping the femur stable.
3. Clinical findings :
I. Positive test :
The test is said to be positive if there is a lack of a definite endpoint and significant anterior translation of the proximal tibia relative to the unaffected side.
II. Anterior drawer test :
1. Purpose :
- The anterior drawer test is a physical examination that clinicians perform to assess the anterior cruciate ligament’s stability in the knee (ACL).
- This test may not be as accurate as other diagnostic techniques in determining an ACL damage.
2. Procedure :
- First we have to do the sag sign. If it comes positive, then the outcome of the test will be different.
- The patient is said to lie-down in supine position with the hip flexed at 45 degree and both the knees flexed to 90 degree.
- Also both the heels should lie on the table or bed.
- Then, with both hands, firmly grab the upper leg.
- To observe hamstring relaxation, we must keep our thumbs on the tibial tuberosity and our fingers posteriorly.
- Then, with the purpose of pulling the leg, apply force and examine for any subluxations.
- Finally, on the opposite side, repeat the procedure.
3. Clinical findings :
Positive test :
Now take note and compare; if there is a greater amount of anterior subluxation than there is posterior subluxation, this is known as a ‘positive anterior drawer sign.’
III. Mcintosh test/Pivot-Shift test :
1. Purpose :
- The goal of this test is to find out if you have anterolateral rotational instability in your knee.
- The ACL, LCL, posterolateral capsule, arcuate complex, and ITB are all structures that could be harmed if this test is positive.
2. Procedure :
- The patient is said to lie-down in supine position with the knee extended.
- Then stand open the affected side of the patient.
- By placing his extended thumb over the fibular head or neck, the examiner grasps the lateral femoral condyle with his hand.
- The examiner grasps the ankle with the other hand and rotates the leg medially.
- The examiner then administers valgus stress by abducting the leg forcibly and progressively flexing the knee.
3. Clinical findings :
Positive findings :
When the subluxed tibia descends to around 30 degrees of flexion, the examiner will feel a “click.”
So the test is positive, it means the anterior cruciate ligament has been injured.
IV. Single leg hop test :
1. Purpose :
- Whether it’s an ankle sprain, stress fracture, or anterior cruciate ligament replacement, a set of hop tests are frequently performed in the assessment for return to sports following an injury.
- They are both functional and quantitative, allowing for the comparison of the damaged and unaffected leg’s power and strength.
2. Procedure :
- The goal of this test is to jump as far as possible on a single leg while maintaining balance and landing solidly. The distance is calculated from the starting line to the landing leg’s heel.
- The goal is to have a difference in hop distance between the injured and uninjured limbs of less than 10%.
3. Clinical findings :
Positive finding :
If the person able to jump as per the instruction, then this test is said to be positive.
Then operative ACL reconstruction may not be indicated.
V. Hughson jerk test :
1. Purpose :
This test is done in ACL injury to check the anteroom lateral rotation instability.
2. Procedure :
- The patient is said to lie-down in supine position with the hip flexed at 45 degree and knee flexed at 90 degree.
- The the examiner use one hand to apply internal tibial rotation at the ankle.
- The other hand is placed over the proximal tibial plateau and fibula.
- Then we have to apply valgum force to the knee.
- And finally the knee is slowly extended.
3. Clinical findings :
Positive findings :
If there is a sudden acceleration or jerk during the movement usually at around 30 degree of flexion characterised by the anterior subluxationof the lateral tibial plateau.