ACL Tear
ACL Tear Overview
An ACL tear is a common knee injury involving the anterior cruciate ligament (ACL), one of the main ligaments stabilising the knee joint. The ACL connects the femur (thigh bone) to the tibia (shin bone) and plays a critical role in controlling forward motion and rotation of the tibia. Tears can range from a mild sprain to a complete rupture.
Symptoms
Pop sound at the time of injury: Often heard or felt when the ligament tears.
Immediate pain: Ranges from moderate to severe and often prevents continued activity.
Swelling: Rapid swelling within hours.
Instability: Feeling that the knee may give way during movement.
Reduced range of motion: Difficulty straightening or bending the knee.
Tenderness: Pain when pressing on the knee or specific motions.
Causes
Trauma:
Sudden pivoting or cutting movements (e.g., in soccer, basketball).
Landing awkwardly from a jump.
Direct impact to the knee (e.g., during contact sports or accidents).
Overextension: Excessive straightening of the knee.
Weakness or imbalance: Poor conditioning of muscles surrounding the knee.
Types of ACL Tears
Partial tear: Ligament is damaged but still partially intact.
Complete tear: The ligament is fully severed.
Associated injuries: Often occurs with damage to other structures, such as:
Meniscus tears.
MCL (medial collateral ligament) tears.
Bone bruises.
Diagnosis
Medical history and physical examination:
Lachman test: Checks for forward movement of the tibia.
Anterior drawer test: Similar to the Lachman test but with the knee bent at 90 degrees.
Pivot-shift test: Detects instability during rotational movement.
Imaging:
X-rays: Rule out fractures.
MRI (Magnetic Resonance Imaging): Provides detailed images of the ACL and surrounding tissues.
Treatment
Non-surgical options:
R.I.C.E. Protocol
Rest: Avoid activities that strain the knee.
Ice: Apply for 15–20 minutes every few hours to reduce swelling.
Compression: Use a knee brace or elastic wrap.
Elevation: Keep the leg elevated to reduce swelling.
Physical therapy
Strengthening exercises for muscles around the knee (quadriceps, hamstrings).
Balance and proprioception training to stabilise the joint.
Bracing: Supports the knee during recovery or activity.
Surgical Options
Surgery is often recommended for:
Complete tears, especially in young or active individuals.
Combined injuries (e.g., ACL + meniscus tear).
Persistent knee instability.
ACL Reconstruction:
The torn ACL is replaced with a graft from the patient's own tissue (autograft) or a donor (allograft).
Common graft sources:
Hamstring tendon
Patellar tendon
Quadriceps tendon
Recovery Process
Post-surgery rehabilitation:
Weight-bearing with crutches initially (usually 1–2 weeks).
Gradual progression to full weight-bearing and range of motion exercises.
Strengthening and functional training typically begin after 4–6 weeks.
Return to sports in 6–12 months, depending on recovery.
Non-surgical recovery:
Physical therapy is the cornerstone, with a focus on strengthening and stabilising the knee.
Full recovery may take 3–6 months, though some instability may persist.
Complications
Chronic instability if left untreated.
Recurrent injuries or graft failure post-surgery.
Knee stiffness or loss of range of motion.
Osteoarthritis in the long term.
Prevention
Strength training:
Focus on the quadriceps, hamstrings, glutes, and core muscles.
Plyometric exercises:
Improve landing mechanics and reduce stress on the ACL.
Balance and proprioception training:
Enhance joint stability during dynamic movements.
Proper technique:
Avoid landing with knees inward (valgus collapse).
Protective gear:
Knee braces may provide additional support in high-risk activities.
Prognosis
Surgical reconstruction provides excellent outcomes for most patients, with many returning to pre-injury activity levels.
Non-surgical treatment can be effective for older, less active individuals or those with partial tears.
