The Knee Ligaments

The knee ligaments, function like all ligaments to strengthen the joint and prevent unwanted movement and hold the joint in a stable position throughout its normal movement.

There are four knee ligaments that warrant attention and a fifth type that also deserves a mention.


There are two cruciate ligaments:

the anterior cruciate ligament

the posterior cruciate ligament.

They are pencil like structures situated inside the centre of the knee joint. They join the femur and tibia together running diagonally, in opposite directions to each other, which is where they get their name from, as cruciate means cross.

Their job in the knee is to limit excessive rotation and forward and backward 'play' in the knee.

They are regarded as strong structures and will only be damaged in situations of reasonable force.This is commonly in sporting injuries and other high velocity incidents such as road traffic accidents. The mechanism of injury usually involves a rotation element and/or a force moving the femur or tibia forwards or backwards relative to each other. They are sometimes injured in isolation but often it is in conjunction with other structures in the knee.

When damaged the cruciate knee ligaments normally bleed into the joint as they have a good blood supply. This can cause almost immediate swelling after an injury and is one of the pieces of information a specialsist will use to help with a diagnosis.

The cruciate knee ligaments may be partially torn or fully ruptured. Marked instability can result from a torn cruciate knee ligament. This can be easily tested for by an experienced professional and again is used as a strong indicator of the exact problem.

People with cruciate damage can learn to live with it. In fact many have learnt to compensate for the loss of the total or partial loss of the ligament by cleverly and often subconsciously adopting certain movement patterns and muscle contractions in their activities. There is, however, often a price to pay for this type or situation in that the abnormal patterns of movement and function can over the long term cause damage and wear to the knee, which has consequences for early degeneration.

The anterior cruciate knee ligament is seemingly more commonly injured than the posterior. The techniques of surgical and non surgical intervention of these ligaments, particularly the anterior cruciate, are both highly developed and successful.They do, however, require considerable focus and determination over a period of months to achieve solid results.


This is not a detailed investigation and explanation of the fantastically interesting intricacies of arthroscopic orthopedic surgery. I am not an orthopedic surgeon I am a physical therapist and rehabilitationist. I have, however, had considerable experience of different techniques of surgery which I will mention here. All of which have been surgical repair of the anterior cruciate ligament. I am yet to come across a posterior cruciate repair.

Reconstruction of a damaged anterior cruciate ligament has commonly been done using both man made fibres and tissue harvested from elsewhere in the body. Initial repairs were done using carbon fibre to replace the ligament. Progress has seen the use of part of the hamstring muscle taken from near to the knee joint or part of the quadriceps or patellar tendon at the front of the knee. I have been fortunate enough to have seen a number of such procedures performed prior to being able to take responsibility for their rehabilitation.

Personally I have found that the most successful procedures have been the ones done using the middle third of the patellar tendon. This is purely my experience and is based on nothing else. Don't get me wrong I have seen many good results using other techniques but the patellar tendon graft has the edge for me. The only down side is the temporary weakness and problems that can occur with the tendon from where the graft has been taken. These challenges though are generally short lived.


Wow, what a topic. The rehabilitation of anterior cruciate ligament surgery is in my opinion at the epicentre of what rehab is all about. It is long term, demanding, littered with plateaus and potholes and will sort out the men from the boys in terms of both therapist and patient. I have seen some pretty poor outcomes and seen many not see out the routine grind of the often monotonous rehabilitation process involved.

I have also felt the pride and satisfaction of a hard road walked when the patient leaves the gym smiling and confident with an inner knowing that they have the work done and in the bank. Anterior cruciate rehabilitation has the capacity to change people physically and psychologically because of its duration and demands. It is a wonderful course to follow with all its ups and downs.

Many surgeons have their own rehabilitation protocols that they like used. Others leave it entirely to the therapist. In terms of time, full recovery from surgery to full contact sport stage or comparative level is normally around nine months. This can vary with individuals and I have experience of both the six and twelve monthers as well as everything in between.

The key though is DOGGED PERSISTENCE.

To find out more about the rehabilitation of anterior cruciate knee ligaments follow this link


There are two two collateral knee ligaments:

The medial collateral ligament

The medial collateral knee ligament is one of the most commonly injured structures in the knee. It runs along the inside (the aspect of the knee nearest to the other one known as the medial aspect). It strengthens the joint to prevent the tibia moving outwards or laterally in relation to the femur. It also prevents excessive rotation of the tibia.

It is commonly injured in sports or slips and falls when the knee is suddenly forced into a 'knock knee' position or if the upper body rotates when the leg is fixed (often by studs in sports footwear) overstretching the medial ligament. The other thing of importance with this ligament is that it has an attachment to the medial meniscus or cartilage. This means that if the ligament is stressed sufficiently there can be associated damage to the meniscus.

The lateral collateral knee ligament

This ligament is much less commonly injured. It is thicker and structurally more resiliant than its medial counterpart. It lies on the outside or lateral aspect of the joint to prevent unwanted inward movement of the tibia against the femur. It is not attached to any of the menisci.

Coronary Ligaments

I am only really mentioning these for the sake of completeness. They are relatively unimportant in comparison to the other major structures discussed above. They are tiny stitch like ligaments that attach the outer borders of the menisci to the tibia. Occasionally they get inflamed in sports people but are more of an irritant than anything else.


Unless there is total rupture of the collateral ligaments surgery is usually avoided. Although it has been done the results have not been fantastic with a great deal of joint stiffness and pain being present after rehabilitation. The norm is immobilisation in a brace or cast to allow healing of the damaged ligament ends, followed by controlled but strong rehabilitation.


Rehabilitation of injured collateral ligaments is relatively straightforward. There are however pitfalls. These are commonly not rehabilitating the structure fully with re-injury or iritation a distinct possibility. There are key movements that must be done before discharge from therapy to ensure as far as possible that re-injury will not occur.