
Anterior Cruciate Ligament (ACL) Injury

The anterior cruciate ligament (ACL) is one of the key ligaments that stabilizes the knee, especially during twisting, pivoting, and sudden directional changes. ACL injuries are among the most common sports-related knee injuries, with an estimated 100,000+ ACL tears occurring annually in the U.S. They often happen during sports like soccer, basketball, football, or skiing, typically when stopping suddenly, landing awkwardly, or changing direction quickly. An ACL tear can cause significant instability and often requires surgery followed by structured physical therapy for full recovery.
Diagnosis of ACL
ACL injuries are diagnosed with a combination of clinical tests and imaging:
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Medical history review (injury mechanism, popping sound, immediate symptoms).
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Physical exam using stability tests (e.g., Lachman test, anterior drawer test).
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Imaging:
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MRI is the gold standard for confirming ACL tears and ruling out meniscus or cartilage damage.
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X-rays may be used to rule out fractures.
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Treatment for ACL
Treatment depends on the severity of the injury and the patient’s activity level. Physical therapy plays a vital role in both non-surgical management and post-surgical rehab. Therapy may include:
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Pre-surgical therapy (“pre-hab”) to reduce swelling and strengthen the knee before surgery
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Post-surgical rehabilitation to restore mobility, stability, and strength
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Manual therapy to reduce stiffness and improve joint motion
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Strengthening exercises for quadriceps, hamstrings, and hip stabilizers
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Balance and proprioception training to restore stability and prevent reinjury
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Education on safe return-to-sport progression and injury prevention strategies
Symptoms of ACL
Common signs of an ACL injury include:
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A popping sound at the time of injury
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Immediate, severe knee pain
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Rapid swelling within a few hours
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Instability or “giving way” when walking or pivoting
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Difficulty bearing weight on the injured leg
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Loss of full range of motion
Prevention of ACL
To reduce the risk of ACL injuries or reinjury:
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Perform neuromuscular training programs focused on landing mechanics, agility, and balance
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Strengthen quadriceps, hamstrings, hips, and core for stability
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Stretch regularly to maintain mobility in the legs and hips
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Use proper jumping and landing techniques during sports
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Wear supportive footwear that fits your activity
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Address early signs of knee instability before returning to play
