Knee Ligament Injury Info Sheet

This general information sheet contains a summary of details concerning knee structures and various treatments for your ligament injury. It is intended only as an introduction to ligament injuries.

Areas of the knee that can be damaged:

  • Ligaments
  • Meniscus (cartilage)
  • Patella (knee cap)

How a ligament can tear (mechanism of injury):

  • Sudden twist
  • Hyperextension
  • Direct contact

The meniscus is a key structure for smooth knee function.

  • Damage to a meniscus occurs 50% of the time when a ligament is torn.
  • Damage to a meniscus must be treated early to prevent permanent damage to the joint lining. You can often repair a damaged meniscus with good results.
  • The meniscus should be treated even if the ligament is not repaired to reduce pain and preserve long term function of your knee.
  • Loss of a meniscus usually means some form of wearing of the joint lining will occur ("wear and tear arthritis"). Patients will commonly give up twisting/turning high intensity sports (racquetball, basketball) or high impact sports (jogging) if a meniscus is severely damaged.

Joint lining damage is permanent.

  • Joint lining damage can occur at the time of your initial injury and be a cause for pain.
  • Damage may be small and isolated or involve the entire joint surface. Your treatment will depend on the type of damage.

Do you need the anterior cruciate ligament (ACL) repaired?

Yes if:

  • You want the best knee possible.
  • You routinely engage in active sports that involve turning or twisting.
  • You have meniscus damage that is extensive or requires repair.
  • Your knee is loose and gives way with normal walking.

No if:

  • You do not engage in active sports
  • You are willing to modify activities.
  • You are willing to risk a future giving-way episode. Be aware that your knee may give-way unpredictably with any sport and further damage to the joint lining or meniscus could occur.

Please realize you have an 80% chance of needing future surgery if you begin to experience giving-way during normal walking without ligament surgery.

What is the success of ACL surgery?

  • 90% chance of returning to pre-injury athletic level
  • 95% chance of returning to twisting, turning sports
  • Without surgery there is a 33% chance of returning to pre-injury athletic level

What advances have been made to increase the success rate?

  • Knee motion after surgery to prevent scarring (no casting).
  • New rehabilitation advances to regain muscle function and joint motion.
  • Strong grafts to replace ligament (cannot repair the ligament alone - not effective).
  • Grafts used to replace the ACL itself rather than a non-anatomic repair.
  • Procedure performed through an arthroscope.
  • Limited incisions used, cosmetically placed.

What are the risks of ACL surgery?

  • 1-2% chance of infection requiring treatment.
  • 5% chance of knee scar formation causing motion problems.
  • Other risks with surgery such as anesthesia, phlebitis, etc. are slim but do exist.

What is the post-operative rehabilitation program?

  • Outpatient surgery with knee motion and rehab begins on day of surgery.
  • Intensive exercises and rehabilitation usually with a physical therapist for two months.
  • The first eight weeks after surgery is where a good result is obtained. Do everything requested and follow your exercise protocol. Do not put-off or avoid your exercises.
  • You will be able to do light office work at 1 week after surgery.
  • You will be able to perform strenuous work or stand all day at 2-3 months after surgery.