Knee
Multi-Ligament Knee Injuries
What is a multi-ligament knee injury?
A multi-ligament knee injury occurs when two or more ligaments in the knee are damaged.
The knee contains two cruciate ligaments in the center of the joint that control front-to-back stability.
The ligament in the front is the anterior cruciate ligament (ACL).
The ligament in the back is the posterior cruciate ligament (PCL).
On the sides of the knee are the collateral ligaments, which stabilize the knee during side-to-side movement:
The ligament on the inside is the medial collateral ligament (MCL).
The ligament on the outside is the lateral collateral ligament (LCL).
In addition to these, several other ligaments and tendons on the inner and outer sides of the knee help control rotation of the tibia (shin bone). These include:
The posterior oblique ligament (POL) on the inside of the knee.
The popliteus tendon and the popliteofibular ligament on the outside of the knee.
There is also an important structure on the back of the knee called the oblique posterior ligament, which prevents the tibia from bending backward (a condition called recurvatum).
What causes a multi-ligament knee injury? What is a knee dislocation?
A knee dislocation is the term used to describe a multi-ligament injury that involves both cruciate ligaments (ACL and PCL). This is a serious condition because the knee is very unstable and can result in severe damage to blood vessels and nerves. These injuries can potentially be life- and limb-threatening, and therefore these injuries are medical emergencies.
There are basically two types of knee dislocations: sports related and high energy dislocations (motor vehicle crash, fall, etc.). If a knee dislocation occurs during a sporting event, it is critical to reduce the knee back to its normal position (putting the ends of the bones back in alignment). When a knee dislocation happens after a high-velocity impact, such as a motor vehicle accident or a fall from a significant height, this can be a more serious injury, because the skin and other soft tissues such as the muscles, tendons, nerves, and blood vessels can be severely damaged.
What are the symptoms of a multi-ligament knee injury?
Symptoms depend on the severity of the injury and the number of anatomical structures involved. Below are some of the most common symptoms of a multi-ligament knee injury:
- Pain: Diffuse knee pain. The pain may range from mild to severe, depending on the extent of the injury.
- Swelling
- Stiffness: The knee may become stiff, making it difficult to fully bend or straighten the leg.
- Instability: An individual with a torn ligament may feel that the knee is unstable, as if it’s “giving way” or unable to support their weight properly.
- Bruising: Bruising can develop around the site of the ligamentous injuries, and the discoloration is often seen on the inner side of the knee.
- Difficulty Walking: Walking may be uncomfortable or painful, particularly if the multi-ligament injury is severe.
- Popping or Clicking Sensation: Some people report a popping or clicking sensation when the injury occurs, which may be followed by pain and swelling.
What are the first steps after a knee dislocation? How is a multi-ligament injury diagnosed?
If a knee dislocation is suspected, it is critical to go to the emergency room immediately for a detailed evaluation of the skin, surrounding muscles, pulses, and especially the condition of the popliteal artery.
The popliteal artery is the main blood vessel supplying the lower leg and runs directly behind the knee. During a knee dislocation, this artery can be damaged, potentially compromising blood flow to the entire lower leg. If there is any concern for an arterial injury, your doctor will order a CT angiogram, a scan in which dye is injected into the blood vessel to identify any damage.
If there is no artery or nerve injury, and the joint has been successfully reduced (put back into its normal position), Dr. Bryan Penalosa will then evaluate whether the knee remains stable or if it continues to slip out of place.
If instability persists, a cast or brace may be required to hold the knee in proper alignment.
If the joint remains stable after reduction, Dr. Penalosa will perform a thorough physical examination to assess range of motion and evaluate the integrity of all ligaments.
Next, Dr. Penalosa will order an MRI scan to examine the cartilage surfaces, ligaments, and menisci for additional injury. A specialized set of x-rays, called stress x-rays, will also likely be obtained. These stress x-rays help Dr. Penalosa accurately measure and diagnose—down to the millimeter—injuries to the posteromedial corner, posterolateral corner, or PCL, using validated classification systems.
Multi-Ligament Knee Injuries Treatment Options
Can a multi-ligament knee injury be treated without surgery?
Multi-ligament knee injuries typically do not heal on their own. In these injuries, the knee is very unstable. In order to restore knee function and stability, surgery is required.
What are the surgical options for a multi-ligament knee injury?
Whenever possible, surgery within the first two weeks after a knee dislocation is recommended to stabilize the knee if satisfactory range of motion has been achieved. Attempting to operate on a stiff knee can jeopardize the outcomes of the procedure. In healthy patients with an acceptable range of motion, who do not have any lacerations or problems around the area of the knee dislocation, surgery is indicated to reconstruct the injured structures.
Surgery for a knee dislocation resulting in a multi-ligament knee injury is serious. Reconstructing the torn ligaments and repairing the torn menisci (if present) in one surgery works best so as to not put too much stress on any one graft/reconstruction. Therefore, it is essential that surgery is performed in an efficient manner that minimizes the anesthesia and surgical time. Dr. Penalosa is the complex multi-ligament knee surgeon at Midwest Orthopaedics at Rush. Dr. Penalosa and his surgical team routinely perform multi-ligament reconstructions and have implemented a practice within the operating room that optimizes efficiency and mitigates the total surgical time, enhancing patient outcomes.
What is the prognosis after knee dislocation surgery?
In general, most sports-related knee dislocations heal well after surgery. The incidence of artery injury is less than 1 percent, and multi-ligament reconstruction surgery is usually effective.
The results for high-velocity knee dislocations are less predictable because of the amount of injury to soft tissues and other structures. These patients may need to be followed more closely to ensure that their knee motion is progressing appropriately without developing significant stiffness and that their knee ligament reconstructions do not stretch out because of other soft tissue injuries.
Because of the significant trauma associated with a knee dislocation, most patients will start to develop arthritis within ten years. This is probably a result of some of the cartilage cells being killed or significantly damaged during the initial impact. Unfortunately, there are not great options to treat this other than to ensure that the patient restores their muscle mass. Restoring muscle mass allows patients to have better shock absorption with everyday activities, better preserving the overall health of the knee joint. Preserving the torn menisci is also essential. If the meniscus needs to be taken out, the risk of later osteoarthritis is significantly increased.
Recovering from Multi-Ligament Knee Surgery
How long is the recovery after multi-ligament knee reconstructive surgery?
After surgery, physical therapy typically begins on post-operative day 1 or 2. Early motion is essential to prevent the reconstructed knee ligaments from stretching out and to avoid post-operative stiffness. In some patients, excessive scar tissue may form due to the severity of the injury and the surgery itself, which can significantly limit motion if not addressed early. To prevent this, there is a strong focus on regaining knee movement immediately after surgery. Dr. Bryan Penalosa will provide a detailed and specific post-operative rehabilitation protocol for you and your physical therapist to follow.
Following multi-ligament knee reconstruction, patients must remain non-weight bearing for the first six weeks after surgery to protect the reconstructed structures. Driving with the operative leg is usually permitted around 7–8 weeks post-op, depending on comfort and progress.
Endurance and strengthening exercises begin in the second phase of rehabilitation. Agility training typically starts around 4.5 months post-op, along with a gradual running progression once earlier milestones have been met successfully. Most patients return to sports between 9 and 15 months after multi-ligament knee reconstruction, depending on healing, strength, and functional progress.
Patient Resources
Orthopedic surgeon Dr. Bryan Penalosa and his team are dedicated to providing an industry-leading patient experience—one that is smooth, efficient, and convenient. Our team has compiled a comprehensive set of orthopedic patient resources to assist you with insurance information, patient forms, and much more.
Explore the patient resources below to learn more.
- Preparing for Surgery
- Traveling for Surgery
- Pre-Operative Clearance
- Peri-Operative Nutrition
- Post-Operative Instructions
- Post-Operative Physical Therapy
- Post-Operative Medications
- Durable Medical Equipment
- Billing & Insurance
- Patient Portal
- Medical Records
- Patient IQ
- Clinical Case and Imaging Review
- Ongoing Clinical Trials
- Sports Performance Center