Knee Dislocation Surgery - Procedure and Post-Operative Instructions

Introduction:

The synovial joint connecting three bones, the thigh bone (femur), the knee cap (patella), and the shin bone (tibia), is called the knee joint. It is responsible for the movements such as extension, flexion, and medial and lateral rotation. Many ligaments, tendons, and cartilages are responsible for the proper functioning of the knee joint. Ligaments that support the knee are anterior and posterior cruciate ligaments; medial and lateral collateral ligaments. Knee dislocation occurs when there is a disruption in the position of any of these three bones.

What Are the Causes of Knee Dislocation?

Knee dislocation is an uncommon injury but extremely serious and caused mainly due to:

• Major accidents, trauma such as a fall from heights, or sports injuries.

• It may occur in old age as muscles and bones become weaker.

• In minor injuries like a missed step or a sudden unusual joint twisting.

• Patients with genetic disorders like Larsen syndrome, Ehlers-Danlos syndrome, and Ellis-van Creveld syndrome are susceptible to knee dislocation.

What Are the Symptoms of Knee Dislocation?

• Severe pain and swelling with bruises.

• A popping sound was heard at the time of injury.

• Locking or catching sensation.

• Limitation of movement.

• Instability and unable to perform daily activities.

What Are the Types of Knee Dislocation?

• Dislocation of the knee can be classified based on the movement of the tibia bone about the femur bone as anterior, posterior, lateral, medial, and rotational. Anterior dislocation is known to be the common type. Rotational dislocations can be classified into anteromedial, anterolateral, posteromedial, and posterolateral. Posterolateral dislocation is considered one of the most difficult injuries to treat by closed reduction.

• It can also be classified as high-velocity and low-velocity injuries. High-velocity injuries are mainly due to major accidents or during football or soccer matches which cause a sudden and violent force on the tissues leading to hyperextension and disruption. Low-velocity injuries are less severe and have a better prognosis.

• Schenck classified knee dislocation based on the number of ligaments damaged during the injury:

• Knee Dislocation (KD I): Injury to a single ligament, either the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL).

• KD II: Injury to both ACL and PCL.

• KD III: Injury to both ACL and PCL, along with medial, lateral, or fibular collateral ligament injury.

• KD IV: Injury to both ACL and PCL, along with medial and fibular collateral ligaments.

• KD V: Knee dislocation along with fracture.

What Are the Complications of Knee Dislocation?

Knee dislocation should be treated immediately; otherwise, it can lead to :

• Deep vein thrombosis or clotting of blood in the deep veins of the legs due to long periods of inactivity.

• Swelling in the muscles can put pressure on the nerves and blood vessels, increasing pain intensity; it is called compartment syndrome.

• It can sometimes lead to amputation of the knee due to the cessation of blood flow.

How Is Knee Dislocation Diagnosed?

Knee dislocation requires immediate attention; the doctor initially takes a complete medical history and conducts a physical examination.

• Pulse is checked at several areas like the posterior tibial and dorsal pedal regions.

• Ankle-brachial index (ABI) may be conducted in severe injuries to determine the extent of involvement of arteries. It is done by measuring the blood pressure in the arm and the ankle. A decreased or low ABI indicates poor blood flow to the lower extremities.

• A sense of sensation and touch is assessed to rule out nerve involvement. The doctor may suggest electromyography to check the muscles and nerve activity and an arteriogram or a doppler ultrasound which shows the outline of the blood flow in arteries and veins and helps to assess the damage to the blood vessels.

• An x-ray and magnetic resonance image (MRI) are advised to assess the condition of ligaments, muscles, and tendons. X-rays help to determine the location and extent of the fracture and also the associated bony irregularities. MRI helps confirm the diagnosis and also helps to diagnose any associated soft tissue injuries and nerve involvement.

What Is the Treatment for Knee Dislocation?

The treatment generally is based on the severity of the injury to the patient.

• Medications, such as Acetaminophen, Codeine, Fentanyl citrate, and Meperidine are given for pain. If it is a moderate injury, the doctor may try to put the bone back in its place by pressing and moving it in certain ways known as traction, extension, rotation, etc., called closed reduction. When the joint is back in place, it is prevented from mobility by supporting it with a splint for around three to ten weeks, depending on the severity. Surgical stabilization is usually advised only after closed reduction for a better prognosis.

• Surgical treatment or open reduction becomes necessary in patients with severe injuries or when closed reduction is impossible. Surgery is planned after the swelling reduces; till then, a splint is advised. It generally depends on the ligaments involved and the severity of the injury. It is decided based on the MRI reports of the patient. Some surgeries performed in knee dislocation are arthroscopic keyhole surgery and open surgery.

• Arthroscopic Keyhole Surgery: It is a minor surgery carried out under general anesthesia, which involves the insertion of a tube-like instrument called an arthroscope, a flexible tube-like device consisting of a camera and a light. It helps the surgeon visualize the knee internally as the device is connected to a monitor screen. Two holes are punctured on either side of the knee cap tendon; the arthroscope is inserted through one hole, and the other surgical instruments are inserted. This procedure removes and washes out the fragments of bone, cartilage, or other loose bodies floating in the knee and smoothens the rough and frictional surfaces. It reduces the pain and trauma of the patient with only minimal scarring. The patient recovers in three to five days. It is a safe and low-risk surgery but cannot be performed in case of severe injuries to the knee joint.

• Sports injuries or injuries due to major accidents need to be treated by open surgery. These injuries involve the rupturing of one or more ligaments. Surgical treatment of these injuries is by reconstruction and repair procedures.

• Reconstruction: It is performed by removing the injured tissue, which is replaced by a graft. Grafting is usually done from the patient's tissue from the patellar tendon or hamstrings; it is called an autograft. If the tissue is from a donor, it is called an allograft. The graft is fixed at the site by creating tunnels from the thigh and shin bone.

• Repair: It involves stitching the ends of the cartilage, which are torn due to the injury, and bracing them together to hold it in place with the help of fiber tape. Small holes are drilled, and the tape is passed through the tunnel to fix the ligament.

• Medial collateral ligament injuries are common and are initially treated with knee bracing and holding the knee in a bent position for four to six weeks. However, surgery is advised if the injury is severe or multiple ligaments are involved.

• Multi-ligament injuries involve two or more ligaments, major blood vessels, and nerves, and surgery is conducted through proper planning and evaluation.

• Cartilages are present between the thigh and the shin bone, which act as shock absorbers, and any damage to these structures is called meniscus tearing or meniscus damage. Minor cases are treated by trimming the meniscus with an arthroscope. Major meniscus damage injuries are treated by meniscal transplantation, which involves transplanting meniscal tissue from a donor and implantation.

What Are the Post-operative Instructions in Knee Dislocation Surgery?

The post-operative recovery depends on the extent and severity of the underlying injury. Splints and braces help to stabilize and perform daily activities. Upon removal of the splint, muscle-strengthening exercises are advised for a few months under the guidance of a therapist. Crutches are advised for a few weeks, and Range of motion (ROM) therapy is started, wherein exercises involving all the knee movements are practiced and help the patient in early recovery.

Conclusion:

Knee disclocation occurs when there is a disruption in the knee joint, and the knee bone slides out of place. It is a high-energy trauma characterized by severe pain, swelling, bruises, limited movement, etc. It can be diagnosed by physical and radiological examinations. The surgical method depends on the severity of the injury, and knee dislocation surgery helps to stabilize the knee, lowers the risk of recurrent dislocation and prevents further complications.