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🏥 Gotokuji Orthopedic Clinic / Patient Guide

ACL Injury

Anterior Cruciate Ligament Injury
A knee ligament injury caused by sudden direction changes in sports

The anterior cruciate ligament (ACL) connects the thighbone to the shinbone and keeps the knee stable.
When a sudden change of direction, stop, or pivot during sports puts too much force on the knee, the ACL can stretch, partially tear, or completely rupture.
It is most common in sports with frequent cutting and pivoting, such as soccer, basketball, rugby, and skiing.

1
Sudden direction change or stop

A rapid pivot or deceleration while running places extreme stress on the knee

2
Twisting force applied to the knee

The body rotates faster than the knee can follow, creating a powerful twisting force

3
The ligament tears

The ACL exceeds its limit and suffers a partial or complete tear

4
The knee becomes unstable

Without the ACL's support, the knee feels loose and may buckle (give way)

⚽ Soccer 🏀 Basketball 🏉 Rugby ⛷️ Skiing
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A "pop" felt or heard at the time of injury
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Rapid swelling of the knee
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Feeling of instability or the knee "giving way"
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Difficulty fully straightening or bending the knee
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Able to walk but the knee feels weak and lacks confidence
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Early Swelling and Pain Management
Ice to ease pain, and while the swelling settles, keep the knee protected but moving within a pain-free range (how much you can move depends on the injury — follow your doctor's instructions)
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Muscle Strengthening
Focus on building quadriceps and hamstring strength
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Gradual Jogging
Light jogging resumes in the mid-phase (3–6 months)
Sport-Specific Training
Sport-specific drills begin in the late phase (6–9 months)
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Bracing & Support
Knee braces provide stability during daily activities and sports
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Core & Hip Training
Full-body coordination training to help prevent the knee from giving way
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Return to sport typically takes 6–9+ months

With conservative treatment, athletes work through a phased rehabilitation program. Strength recovery and knee stability must be thoroughly confirmed before returning to sport. The timeline varies depending on the sport and individual progress.

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When Surgery May Be Considered
For athletes who need to return to high-demand pivot sports, or if the knee repeatedly gives way, ACL reconstruction surgery may be recommended. The ideal timing is after the initial swelling has settled.

💡 Key Points for Recovery

  • Returning with an unstable knee can lead to repeated giving way, damaging the meniscus and cartilage
  • Clear each rehab stage before moving to the next
  • Have your knee regularly evaluated by an orthopedic specialist
  • "Don't rush — be patient — follow the steps" is the fastest route to recovery