PCL 11 - PCL (Posterior Cruciate Ligament tear)

Mechanism of injury
Most common mechanism of injury of the PCL is the "dashboard injury." This occurs when the knee is bent, and an object forcefully strikes the shin backwards. It is called a 'dashboard injury' because this can be seen in car collisions when the shin forcefully strikes the dashboard. The other common mechanism of injury is a sports injury when an athlete falls on the front of their knee. In this injury, the knee is hyperflexed (bent all the way back), with the foot held pointing downwards. These types of injuries stress the PCL, and if the force is high enough, a PCL tear will result.

Complications
1. Neurapraxia (localized loss of conduction that causes short-term paralysis. Usually, there is no degeneration of the axon and complete recovery often occurs) --> is the most common complication of posterior cruciate ligament (PCL) reconstruction
2. Infection
3. Blood clot formation
4. Swelling, bleeding or damage to blood vessels or nerves
5. Rare instrument breakage during procedures
6. Hemarthrosis (Bleeding into the joint)
7. Anaesthetic complications

Time of Recovery
The use of the scope in surgical procedures results in less trauma to the body when compared to “open” procedures. This has allowed athletes to return to participation faster. Recovery time after arthroscopic surgery varies. - “Simple” procedures such as cartilage resection (removal of a torn cartilage) can have a recovery time of as little as two weeks. - Complex procedures such as an ACL reconstruction can take 4 to 6 months. Actual recovery time can vary from person to person. The surgeon’s repair of the damaged tissue is only half of the recovery. The athlete must rehabilitate the surgical limb to regain normal strength, balance, and sport specific techniques. If the athlete approaches the rehabilitation with a poor attitude the outcome will be poor.

Swelling
Leg should be kept elevated as much as possible for the first few days after surgery. Apply ice as recommended by the orthopaedic surgeon to relieve swelling and pain.

Dressing Care
Avoid directing water at the incisions. Do not soak in a tub. Keep the incisions clean and dry.

Bearing Weight
After most arthroscopic surgeries, patient can walk unassisted. The patient may be advised to use crutches, a cane, or a walker for a period of time after surgery. Weight can be put on the leg when discomfort subsides and strength is regained in your knee.

Exercises to Strengthen Your Knee
Regular exercise is useful to strengthen the leg and knee muscles.

Medications
Antibiotics can help to prevent an infection and pain medication to help relieve discomfort following the surgery.

Anatomy of PCL
Stronger than Anterior Cruciate ligament

Course of ligament: Origin – Posterior intercondylar areas of tibia
Insertion – Anterior part of lateral surface of medial condyle of the femur

Function:

• Limits anterior rolling of femur on the tibial plateau during extension, converting it into a spin.
• Prevents anterior displacement of the femur on the tibia / prevents posterior displacement of tibia on femur.
• Prevent hyperflexion of knee joint

Examination
Medical history:

• WWQQAAAB (story of injury)
• History of knee injuries

Physical examination:

• Inspection and palpation for signs of trauma, inflammation and oedema.
• Movement - reduced
• Compare legs
• Posterior drawer test - with the knee flexed and resting on a surfac, the tibia is pushed backward gently. If it moves too far back, it is an indication of a torn PCL.
• Lachman's test - knee flexed 20-30 degrees, externally rotated, stabilise femur with one hand, other hand applying pressure on anterior tibia, torn pcl will cause pain and a laxity described as a 'soft end point' ie. no PCL restraint.

Investigation

• Xray may show possible fractured bones and/or cartilage but will not show a PCL injury.
• MRI will clearly show a damaged PCL and determine if other ligaments of the knee are also injured.
• Arthroscopy - optic tube inserted into knee joint via small incision. Used to determine extent of knee injury.
• Grade of severity of PCL tears (amount of backward tibial displacement observed when the knee is bent at 90 degrees):

Grade I: Partial tears of the PCL.
Grade II: Isolated, complete tear to the PCL.
Grade III: Tear of the PCL with other associated ligament injury.

Management

• RICE (Rest Ice Compression Elevation)
• For Grade I and II tears, nonoperative treatment is recommended such as: specific rehabilitative exercise programs, electrotherapy, ice and heat treatment or manual therapy treatment.
• Surgical PCL reconstruction difficult due to location of PCL in the knee, so it is reserved for patients with several major knee ligaments injured, or those who can't do their usual activities because of persistent knee instability.
• New PCL graft tends to stretch and become less functional.

Moore and Dalley 5th edition http://www.athleticadvisor.com/FAQs/scope/arthroscopy.htm www.medicinenet.com/arthroscopy/article.htm www.surgeryencyclopedia.com/Fi-La/Knee-Arthroscopic-Surgery.html www.medicinenet.com/arthroscopy/article.htm www.answers.com/topic/knee-arthroscopic-surgery www.emedicine.com/orthoped/topic545.htm