Knee dislocations involve a sprain or tear of multiple major ligaments of the knee, usually three of the four. The four major knee ligaments are the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL).
Knee dislocations usually involve injury to both cruciate ligaments and one collateral ligament. Injury to multiple ligaments can make sports and even day-to-day activities difficult.
What Is a Knee Dislocation?
Ligaments are structures that help maintain the normal relationship between the femur (thigh bone) and tibia (shin bone). They allow motion until certain extremes. Motion beyond these extremes can result in a ligament sprain.
A knee dislocation usually involves injury to multiple major knee ligaments, most often both cruciate ligaments and one collateral ligament.
Causes and Risk Factors
A knee dislocation is caused by a force that exceeds the strength of the ligaments. It usually results from a severe injury, although it may also occur from a non-contact injury, such as stepping in a hole, hyperextending the knee, and twisting.
Risk factors include:
- Sports that require pivoting, jumping, cutting, or changing direction, including basketball, gymnastics, soccer, and volleyball
- Contact sports, including football and rugby
- Sports performed on uneven terrain, including cross-country running and soccer
- Poor physical conditioning, including strength and flexibility
- Improper equipment
Symptoms
Common signs and symptoms include:
- One or more pops heard or felt at the time of injury
- Inability to continue activity after the injury
- Knee swelling within six hours after the injury
- Possible deformity of the knee
- Inability to straighten the knee
- Knee giving way or buckling, often with swelling after repeated episodes
- Occasionally, locking when there is also an injury to the meniscus cartilage
- Rarely, numbness, weakness, paralysis, discoloration, or coldness of the foot and ankle due to nerve or artery injury
Treatment
Immediate repositioning of the bones, if displaced, and evaluation of artery and nerve function must be performed.
Initial treatment consists of medications and ice to relieve pain and reduce knee swelling. Walking with crutches is often recommended. Bracing or casting may also be recommended initially.
Rehabilitation usually focuses on:
- Reducing knee swelling
- Regaining knee range of motion
- Regaining muscle control and strength
- Functional training
- Bracing, often when appropriate
- Education, including avoiding sports that require pivoting, cutting, changing direction, jumping, and landing
Properly timed surgical repair or reconstruction of one or both ligaments, performed by an experienced orthopaedic surgeon, provides the best chance for an optimal result. An artery injury requires immediate surgical attention.
Recovery and Outcomes
If untreated, a knee dislocation will usually result in the knee giving way and recurrent injuries during sports and often during daily activities. Surgery is often required to restore knee stability.
Some athletes never return to sports participation after this injury. The prognosis is much better when there is no injury to the arteries or nerves. Return to sports often depends on the associated injuries and demands of the sport.
Potential complications include:
- Recurrent symptoms, including knee giving way, instability, and swelling
- Injury to the meniscal cartilage, resulting in locking and swelling of the knee
- Injury to other structures of the knee, including bone and articular cartilage, which may result in knee arthritis
- Injury to other knee ligaments
- Knee stiffness or loss of knee motion
- Permanent injury to nerves, resulting in numbness, weakness, or paralysis
- Permanent injury to arteries
- Amputation of the leg due to nerve or artery injury
When to See Dr. Chudik
If you are concerned about a knee dislocation or your symptoms worsen, schedule an evaluation with Dr. Chudik. Immediate evaluation is necessary when the bones are displaced or there are signs of artery or nerve injury.
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com.