Illustration: The Knee journal for knee injuries

A Foster, C Butcher and P G Turner

The Knee

January 2005, Volume 12, Issue 1, Pages 33-35

Orthopaedic surgeons at Stepping Hill Hospital, Stockport, UK retrospectively compared the arthroscopic findings of 75 patients at the time of diagnosis of ACL rupture and the findings at the time of ACL reconstruction surgery. This was achieved by reviewing operation notes on patients who had undergone primary ACL reconstruction performed by the senior author between March 1998 and December 2000.

For inclusion in the study, the patients had to have undergone a prior diagnostic athroscopy of the knee performed by the senior author. All patients in the study had subsequently undergone primary arthroscopic ACL reconstruction using a hamstring graft.

The study group consisted of 61 men and 14 women. The age at injury ranged from 12 to 51 with the mean and median age at injury being 26. Sporting injuries accounted for the mechanism of injury in 54 patients (72%). The mechanism of injury was a road traffic accident in one case and unknown or not documented in the remaining 11 patients.

The authors state that the natural history of the knee following ACL rupture is one of progressive degenerative change. Repeated episodes of giving way due to instability result in recurrent trauma to the articular surfaces and menisci. Ultimately, this can lead to osteoarthritis of the knee joint. The purpose of ACL reconstruction is to restore stability, reduce progressive joint damage and to allow the athlete to return to sporting activities.

The authors found that 35 of the total number of patients (46.6%) had some deterioration in arthroscopic appearance in the interval between diagnosis and reconstruction. Twenty-five of the patients had an interval time between surgeries of less than 6 months and of these patients four (16%) developed a further lesion. The remaining 49 patients had an interval time greater than 6 months and of these patients 31 (63%) had developed a further lesion.

Foster et al found that the most common deterioration since the diagnostic arthroscopy was a meniscal tear, which occurred in 22 patients (62.9% of those with deterioration), followed by degeneration of the articular surface of the knee joint (28.6%, 10 patients) and osteochondral lesions (damage to the bone underneath the articulr surface, representing14.3%, five patients).

The optimal timing for ACL reconstruction is thought to be 2 to 4 weeks following injury. Reconstruction earlier than this, where joint swelling is still present increases the incidence of 'arthrofibrosis', where the thickened graft leads to a restriction of knee joint movement. The findings of this study would suggest that in those patients where ACL reconstruction is indicated, particularly in young athletes, a delay (of greater than six months) in reconstructive surgery has a negative effect on the articular surface of the knee.

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