The knee is a vulnerable joint. Ligaments and cartilage can be injured as players get tackled, when quickly changing direction whilst running and within rucks and mauls.
Torn cartilage is a common injury and involves damage to the meniscus within the knee. The menisci are two half-moon-shaped (C-shaped) pieces of cartilage called menisci lying on the shinbone. The meniscus is called the lateral meniscus; the inner meniscus is called the medial meniscus.
These act as shock absorbers when the body walks or runs, by dispersing the weight. This protects the knee cartilage that covers the bones by allowing the surfaces to slide against one another without damage to either surface. The menisci also help to keep the knee stable.
An injured medial meniscus is more common and can result from an impact on the outside of the knee. It will often be injured along with the medial ligament.
Symptoms to look for
Symptoms of a torn meniscus include some vague pain and tenderness along the joint line where the meniscus is located. There is minimal nerve supply to the meniscus which means that not much pain is felt when damaged. However, the force of the twist will often damage the knee ligaments which are very painful. The knee may swell with use and become stiff and tight.
Other symptoms are locking - the inability to completely straighten the knee. A clunking sound will also be heard, especially when walking down stairs. Long-term, meniscal damage causes wear and tear on the joint surface, leading to degeneration of the joint.
Developing strong leg muscles stabilises the knee which help to prevent cartilage damage.
Injury to the medial collateral ligament (MCL) is caused by a force moving the lower leg out to the side or a blow to the outside of the knee. It may also occur when the studs are caught in the grass and the knee is twisted.
The medial ligament has two parts: One deep section that attaches to the cartilage meniscus and the other attaches further down the joint. The deep part will rupture first and this often means that the cartilage is also damaged. If the impact is really severe then the superficial ligament will rupture and also the cruciate ligaments which cross over in the middle of the joint can tear as well.
Types of tear
There are three grades of tear. A first degree MCL tear will result in pain when the knee is touched. Pain is experienced when the player stands up from a chair. Second degree sprains cause considerable pain when the knee is touched on the inside and swelling may occur within 24 hours. A third degree MCL tear is when the ligament is completely torn. The knee is unstable – running or walking becomes near impossible and there is severe and rapid swelling of the knee.
First and second degree tears are usually treated conservatively but most rugby players will opt for surgery in the case of a third degree tear.
The lateral collateral ligament (LCL) is situated on the outside of the knee. Injuries occur during a tackle when force is applied by the opponent to the inner part of the leg just below the knee. Severe cases will also involve damage to the ACL and PCL.
Injuries to the anterior cruciate ligament (ACL), which is situated deep within the knee, are also very common in rugby. This is a very debilitating injury that has serious repercussions for the knee. ACL injuries are becoming more and more common due to the increased intensity of rugby.
The ACL’s main function is to stop the tibia (shin bone) from moving too far forward and to prevent the knee excessively rotating.
The mechanism of this injury can be two-fold: either through a direct blow to the knee in the form of a tackle or from a single plane force where the lower leg is rotated while the foot is fixed because the foot is kept in place by the studs on the rugby boot and there is excessive rotation of the lower leg.
The problem with this injury is that it is seldom just the anterior cruciate ligament that gets injured. Other structures such as the joint capsule, the lateral collateral ligament (LCL) and even the posterior cruciate ligament (PCL) can be and usually are involved. In certain cases there is also the added problem of meniscus involvement.
Pop then pain
The player who suffers from this problem will feel a “pop” followed by immediate pain. The pain is usually felt on the outside and back of the knee. The knee joint often feels very unstable (and in truth it is very unstable) with the result that it will be virtually impossible for the athlete to put their full weight on the knee. Rapid swelling and discoloration of the joint will also accompany this injury.
In the worst case scenario, with the worst degree of ligament injury, the treatment involves an operation to reconstruct the knee with the athlete spending three to five weeks in a brace and up to six months in rehabilitation. If the athlete returns too soon from this injury not he runs the risk of re-injuring the joint. He may also have lingering mental and psychological issues relating to the injury. As a result, he may be fearful and hesitant to perform at maximum intensity on the field. This may lead to sub-par performances on the rugby field with the resultant negative effects that it will have on the athlete.
Prevention includes exercise on a wobble board to improve proprioception and leg exercises to improve leg muscle strength.
The posterior cruciate ligament (PCL) runs from the front of the femur (thighbone) to the back of the tibia (shinbone). It prevents the tibia from moving too far backward relative to the femur. The PCL can be stretched, or partially or completely torn.
PCL injuries are uncommon in rugby and are usually the result of motor vehicle accidents. Cast your mind back to when Bob Skinstad had an injury to the PCL as a result of a motor vehicle accident.
PCL injuries occur as a result of a direct blow to the front of the knee while it is bent, dislocation of the kneecap or injury to other knee structures.
PCL injuries can often be missed because other ligaments compensate for the injured PCL. There is a degree of instability but less pain and swelling than in injuries involving the anterior cruciate ligament or collateral ligaments.
A fracture to the patella can occur with a strong tackle to the knee. An immediate excruciating pain is felt. The knee cap will rapidly begin to swell and the player will be unable to bend the knee. The patella is vitally important to increase the leverage of the knee when kicking. It allows for an increase in strength of 30% when kicking the ball.
(Health24, September 2011)