2000 - Results of Arthroscopic Treatment of Symptomatic Loss of Extension Following Anterior Cruciate Ligament Reconstruction

Hassan SS., Saleem A., Bach BR., Bush-Joseph CA and Bojchuk J. Results of Arthroscopic Treatment of Symptomatic Loss of Extension Following Anterior Cruciate Ligament Reconstruction. Am J Knee Surgery. 2000;37:201-210.

This study concerns 342 patients all having the same procedure (anterior cruciate ligament reconstruction using patellar tendon), and all procedures were performed by the same surgeon.

Five percent of the patients were found after at least four months of intensive physiotherapy to have ‘symptomatic extension deficits’, that is they were unable to fully extend their knee and further efforts to achieve extension were painful. These patients went on the examination under anaesthesia, notchplasty where necessary (widening the bony notch in which the cruciates lie), surgical removal of adhesions, and controlled manipulation. They were then assigned to a closely supervised rehab protocol and the majority were followed up for several years to determine the eventual outcome.

Cause of the Extension Loss

The following were found at surgery to be contributing to the extension loss -

Cyclops Lesion

The surgeons found a cyclops lesion present in 8 of the 13 patients with extension loss.

A cyclops lesion is a lump of fibrous tissue in the notch to the front of the cruciate ligaments. The common symptom of a cyclops lesion was a painless ‘clunk’ as the leg was straightened. In some of the patients the cyclops lesion even contained some cartilage tissue.
Generalised adhesions.

All 13 of the patients in the study had generalised adhesions within the joint, and in all these the surgeon found it necessary to debride (cut away) scar tissue below the kneecap.

Now, although these were not reported to be a problem in this group of patients, the authors of the paper went on to include the following also as recognised causes of inadequate extension after knee surgery -

Incorrect tunnel placement

If the tunnel drilled in the tibia is too far forward (anterior) then the graft which passes through it will impinge on the roof of the notch, injuring the graft and stimulating the formation of a cyclops lesion.

Graft Hypertrophy and Inadequate Notchplasty

If the graft bulks out as it builds its blood supply and takes over the role of the old ligament, then it may prove too fat for the notch. If the notch is adequately widenened during surgery (notchplasty), then this should not prove a problem.

Outcome of Surgery

The authors report that the eventual outcome was that these patients after the secondary surgery and rehabilitation improved from a 10° loss to only a 3° loss, giving no functional difference from the patients who had not had any problem. They did note, however, that these patients were left with some deficit in flexion.

They emphasise that the best management is preventative, and advocate careful patient selection, appropriate timing of surgery, and close attention to graft positioning and the ensuring adequacy of the notch during surgery.

However, for those patients that still go on to an extension deficit, surgery should be undertaken to rectify any problems. In the authors’ opinion this is best undertaken in the 6-12 week period after the ligamanr reconstruction, but patients can still have significant improvement even 8-11 months after the reconstruction.