Anterior Cruciate Ligament Reconstruction

The Anterior Cruciate Ligament links the tibia (shin bone) to the femur (Thigh bone). It is situated in the middle of the knee and is important in controlling movement of the two bones, particularly during sport when changing direction whilst running.

Anterior Cruciate Ligament Tear

The anterior cruciate ligament is commonly ruptured by twisting injuries such as a bad tackle in football or falling whilst skiing. Typically, the knee will 'give way' and there may be a 'popping' sensation. You may even find that you are not able to get up and walk. Typically your knee will swell over the next hour as the ruptured ends of the ligament bleed into the knee.

If nothing is done the knee will slowly settle over six weeks but if you return to sport you may have 'giving way' episodes similar to your initial injury, but not as severe, when you twist and turn.

Diagnosis of ACL injury

The diagnosis depends on a clinical examination at which time the laxity of the ligament can be assessed (possibly with an MRI scan) to see if the cartilages are also damaged. It is often very difficult to examine a knee soon after the initial injury as it is swollen and painful. In this case it is usual to arrange for an MRI scan and physiotherapy to settle the knee down. After a few weeks it is easier to examine the knee and to confirm the diagnosis.

Non Surgical management

It is possible to rehabilitate your knee and get it working well after injury by a course of physiotherapy. This aims to strengthen the muscles around the knee to stop it giving way. If your demands are not high, for instance social tennis rather than league football, it may be possible to get back to your desired level of activity without surgery. However, if you demands are higher and typically if you are younger, physiotherapy is unlikely to make your knee stable enough to get back to your desired level of activity. At this point, surgery may be required.

What happens in surgery?

Anterior cruciate ligament (ACL) reconstruction surgery is an arthroscopic (keyhole) surgical procedure. The same two 5mm incisions are used as for an arthroscopy.

Anterior Cruciate Ligament Graft

The procedure involves excising the damaged ACL and replacing it with a graft of your own tissues. The surgeons at Joint Reaction prefer to use a hamstring graft. In this technique 2 tendons from the inside of your knee are removed via a 3cm incision just below the knee. These tendons are folded in half to make a 4 stranded ACL graft, which is very strong, even stronger than your own, original ACL. Despite the loss of these tendons your hamstring strength will return almost to normal after rehabilitation.

The graft is threaded across the knee via 2 drill holes. The first drill hole enters the knee where the ACL attaches to the tibia and the second is across the knee in the femur, where the ACL is also attached. Both of these drill holes are made through the 3 cm incision used to remove the hamstring tendons.

The graft is pulled through the knee and fixed in place using special screws, which squeeze the graft against the side of the tunnel and hold it firmly in place.

If there is a cartilage tear found at the time of surgery it can be either excised as in an arthroscopic menisectomy or, if small, the cartilage can often be repaired.

What happens after surgery?

You can have an ACL reconstruction performed as a day case, but most patients spend one night in hospital. In day case surgery the knee is filled with local anaesthetic at the end of the operation to numb the pain. If you are staying overnight nerve blocks are generally performed which numb the entire leg.

You will be mobilised by a physiotherapist using crutches and given some exercises to perform. Your physiotherapy rehabilitation will start 5 days after surgery and is split into three 3-month phases.

In the first 3 months you will regain a full range of movement mainly performing 'closed chain exercises'. These are exercises with your foot on the floor or a pedal of a stationary bike that do not over stress the healing graft. After 3 months the graft has healed strongly to the bone in the tunnels either side of the knee joint and your rehabilitation can progress to phase 2.

Between 3 and 6 months you start 'open chain exercises' such as jogging in a straight line and progress to shuttle runs in the gym. You will also do 'proprioception' exercises to train the muscles to respond quickly.

Between 6 and 9 months you can start sport specific training. If you want to play football you can return to training but should avoid tackling and competitive games. You can return to gentler sports such as tennis at this time.

Finally at 9 months your rehabilitation is complete and you can return to your chosen sport with no restrictions.

Success of ACL reconstruction

90% of patients should be able to get back to their chosen sport after an ACL reconstruction. However, if you play a sport at a high level, ie club rugby or semi professional soccer, the chances of returning to your previous level are lower.

Clare Park Hospital | Crondall Lane | Crondall | Farnham | Surrey | GU10 5XX

© Joint Reaction 2008