Anterior Cruciate Ligament (ACL) Reconstruction

Anterior Cruciate Ligament (ACL) Reconstruction is performed when the knee is persistently unstable. It is one of the most common knee operations performed and has excellent success rates with return to competitive sports within 1 year. The procedure is performed as a day case (sometimes patients are kept in overnight) and is done via keyhole (arthroscopic) surgery with a small incision made to obtain the graft (usually your own hamstring tendons).

MRI showing normal ACL

You will have had a MRI to confirm the diagnosis and this will show any other abnormality too (meniscal, cartilage or other ligament injury)

MRI showing torn ACL

What does surgery involve?

The surgery is performed as a day case under general anaesthetic. Via key-hole surgery, tunnels are drilled in the femur and tibia and the graft is secured at both ends.

The graft is fixed in the femur with an endobutton, and in the tibia with a screw.

Which graft is best ?

There are a few different choices for ‘making’ the new ligament. These include using your own patellar tendon, your own hamstring tendon (the two commonest grafts used), or a donor graft from a cadaver (treated to reduce infection and immune response).

Image showing the different types of graft used.

My own preference is to use your own hamstring tendons as this is mechanically the strongest graft. On occasion, I do also use allograft. I will usually have a detailed discussion with each patient on the pros and cons of each type of graft prior to surgery. One important point is that studies have shown no real difference in outcomes where either a patellar tendon or hamstring tendon has been used. There is a higher incidence of anterior knee pain and development of patello-femoral arthritis in patients who have had a patellar tendon ACL reconstruction.

What is the Recovery ?

You will be mobile immediately after surgery and able to put all your weight on the leg. Crutches are used for 4-6 weeks and physiotherapy starts at 2 weeks (although you will be given exercises to perform straight away). There are various milestones to achieve in your rehabilitation (e.g. running at 3 months, pivoting at 5 months) and your recovery depends on when you reach these milestones – not everyone is the same. Full competitive sport resumes at 9-12 months.

 

What are the Outcomes ?

Complications include infection, clots and stiffness. All are very rare. The major complication following an ACL reconstruction is graft failure and the overall risk is 8-10%. Factors which contribute to graft failure are as follows: Poor surgical tunnel placement

Failure to recognise an associated ligament injury (commonly the postero-lateral corner)

Graft fixation failure

Impingement

Trauma leading to the graft being stretched at a vulnerable stage (1st 6weeks)