ACL (Anterior Cruciate Ligament) Revision

Anterior cruciate ligament (or ACL) reconstruction is a safe and effective procedure. However, in about 5-10% of cases, the ACL graft may tear or fail. Higher rates of graft tears of up to 30% have been reported in young patients, who are involved in competitive sport. The risk factors for graft failure include reinjury, technical issues arising from the initial surgery and associated injuries which compromise knee stability. 

The diagnosis of a torn or failed ACL graft is made after a thorough clinical assessment of the knee. MRI scans are done to confirm the diagnosis and to look for concomitant knee injuries. CT scans may also be needed to assess the positions of the bone tunnels used in the previous ACL reconstruction and to look for possible excessive enlargment of these tunnels.


In patients who have symptoms of knee instability due to a torn or failed ACL graft, revision surgery is needed to improve knee stability. The surgery involves drilling new bone tunnels in the knee and securing a new ACL graft within these tunnels. This new graft may be obtained from patient himself (autograft) or from a donor (allograft). At the same time, an extra-articular lateral tenodesis may be added to enhance the stability of the knee. This involves using part of the iliotibial band to secure and improve the rotational stability of the knee. An overnight stay in hospital is usually required after revision ACL reconstruction and 2-4 weeks of crutch-assisted ambulation may be advised. 


Revision ACL reconstruction is a technically demanding procedure and should be carried out by surgeons who are trained and experienced. It is often carried out in one stage, although in a few patients, the surgery may need to be divided into two stages. In the first stage, bone grafting of the old tunnels is done, especially if there is significant widening of these tunnels, as they may compromise graft fixation. The second stage of the procedure is carried out several months later, once the bone grafts have healed and completely filled up the widened spaces within the old tunnels. In the second stage, new bone tunnels are created and a new ACL graft is secured within these tunnels.


The rehabilitation process after revision ACL reconstruction is often slower and longer compared to that following primary ACL reconstruction. It may last up to 12-18 months following the revision procedure. The success rate of revision ACL reconstruction has been reported to be approximately 75%. The complications of this procedure include infection, knee stiffness and recurrent graft failure.

For more information, please contact us.

 

The figure on the left shows a widened bone tunnel (arrowed) within the tibia (shin bone) as seen on a CT scan. The figure on the right shows an allograft (arrowed) that has been used to replace a torn ACL graft within the knee in the revision surgery.

Revision ACL scan
Revision Pic.jpg
 

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