PCL And Multiple Ligament Injuries (Video Link - PCL Reconstruction )
The strength of the knee comes from four ligaments – one on inside of the knee, one on outside, and two in the middle. The one on inside is called MCL (Medial Collateral Ligament), the one on outside is called LCL (Lateral Collateral Ligament), and the two in the middle of the knee are called cruciate ligaments. Usually, it is only one or sometimes two ligaments which get torn. Rarely, more than two ligaments, and sometimes all the four ligaments are torn.
PCL (posterior cruciate ligament) is a major ligament of the knee. It is situated in the middle of the knee in its back part. It is responsible for not allowing the knee to move backward. It may be injured if the knee is hit from the front, for example in a head-on crash, where something from front hits the knee. Injury to this ligament is not as dramatic, and is missed often. In the past, it was thought that PCL injury can be left as it is, and it does not cause much problem. But, it is now understood that PCL is an important ligament, injury to this ligament needs to be treated by surgical reconstruction in many cases. It is a tricky operation as a part of the operation is done at the back of the knee, an area where important nerves and blood vessels of the leg lie. This operation is done by key hole (arthroscopic) surgery.
What is the PCL?
PCL (posterior cruciate ligament) is a major ligament of the knee. It is situated in the middle of the knee in its posterior (back) part. It is responsible for not allowing the knee to move backward.
How is it injured?
It may be injured if the knee is hit from the front, for example in a head-on crash where something from front hits the knee. Injury to this ligament is not as dramatic, and is missed often.
Does it need surgery if torn?
In the past, it was thought that PCL injury can be left as it is, and it does not cause much problem. But, it is now understood that PCL is an important ligament, injury to this ligament needs to be treated by surgical reconstruction in most cases.
How is this surgery done?
This surgery is a key-hole (arthroscopic) surgery. If it is a tear in the middle of the ligament, a new ligament is made from spare tendons graft from back of the knee (hamstring tendons). The graft is fixed on the leg and thigh bones with specialized devices. This procedure is called PCL reconstruction. If PCL comes off with a piece of bone, it is fixed back by key-hole surgery.
Arthroscopic PCL Reconstruction Technique
What are the results of PCL surgery?
Results are excellent with a less than 5% chance of the graft not being accepted by the body. This requires the right rehabilitation techniques.
What are the complications?
Apart from the standard possible complications associated with any ligament surgery, there is small additional risk of injury to the vessels at the back of the knee in this operation. However, they rarely occur if surgery is done in the right way.
What is PCL refixation?
This is a surgical technique used when the PCL comes off with a piece of bone. The ligament is not reconstructed (i.e. a new ligament is not made) but the same ligament is fixed back to the bone by arthroscopic techniques. The rehabilitation is almost the same as a PCL reconstruction
Arthroscopic PCL re-fixation : Sometimes the PCL is avulsed from the tibia, and can be diagnosed on x rays and MRI. The best treatment of such an avulsion injury is to fix it back to where it belongs. This used to be done in the past by open surgery, as back of the knee is a sensitive area - all the important nerves and vessels of the leg travel in that area. With advancement in arthroscopic techniques, this can be done arthroscopically.
What is the post-operative rehabilitation?
It’s almost the same as an ACL reconstruction. The only difference is, that a support is kept under the upper part of the leg and the patient needs to wear a long knee brace while walking for 6 weeks.
Flexion and extension exercises are done in prone position. The restrictions are slightly more than after an ACL reconstruction and near normal walking occurs at about 6 weeks. Running and jogging at 4-5 months and sports after 6-9 months.
MCL (medial collateral ligament) is often injured in a knee bending inward, or when hit from outside. This is one of the easier ligaments, as it heals up in most cases by simple rest in brace. When associated with injury to other ligaments such as ACL, or in obese patients, tear of this ligament may also need surgical attention – repair or reconstruction.
Do we always need to operate on it?
This is a rather friendly ligament and heal up in about half the cases when it is torn off from the thigh bone or the middle of its substance. This healing takes about 6 weeks and requires some element of immobilization like a brace.
When do we need to operate?
Surgery is required when the knee continues to open up from the inside after 6 -8 weeks, or if the injury is from the attachment to the leg bone. Sometimes when associated with injuries to multiple ligaments of the knee, early repair may be required.
What kind of operation is done?
There are two type of operations for MCL injury.
- Repair: This is done when the ligament has just come off its attachment at either end. The original ligament is just repaired back to where it belonged. We sometimes do what is called internal splintage, which means supporting the healing ligament with a thick tape-like structure.
- Reconstruction: This is done when the ligament is completely torn and lacks its original structure. The hamstring tendons (semitendinosus/gracilis) are used to make a new ligament and the same is fixed with specialised devices.
What is the post op rehabilitation?
This depends on whether MCL surgery is done in isolation or with another concomitant ligament.
If done in isolation, the patient is kept on a long knee brace for 6 weeks and is allowed to bend the knee out of the brace keeping the knee in a cross-legged position. Walking is permitted with the brace using a walker/crutches. However for 6 weeks the patient needs to wear the brace while walking.
If done with other ligament reconstruction, the rehabilitation depends on which other ligament is reconstructed.
Postero-lateral Corner injuries
What is the posterolateral corner?
This is a part of the knee on the back of the outer aspect of the knee. It primarily consists of two parts the popliteus tendon and the lateral collateral ligament.
Does it require reconstruction?
More often than not it always requires reconstruction. It is usually never present in isolation and is associated with ACL or PCL tears that are reconstructed at the same time.
How is it reconstructed?
The other legs semitendinosus and gracilis (hamstring tendons) are fashioned into both or one of these ligaments and fixed to the thigh and leg bone at their respective locations.
What is the post-operative rehabilitation?
The patient is kept on a long knee brace for the first two weeks then a hinge knee brace with crutches or a walker. Movement is permitted out of the brace but in prone position.
Multiple ligament injury to the knee
This severe damage occurs in serious accidents. The knee often dislocates, or becomes severely unstable. It becomes impossible to even move the leg in bed. Any attempt at putting load on the leg makes the knee 'give way'. In early stages, there is bluish discolouration of the knee due to the blood seeping out under the skin. In severe injuries, there may occur damage to the nerves and vessels of the leg, and may make this injury limb-threatening. Most young and active patients would need surgery for these injuries. These operations are highly specialized, and only few surgeons experienced in this field can perform them well. Post surgery physiotherapy is an important part of overall treatment.