Functional outcome of septic arthritis after anterior cruciate ligament surgery

Septic arthritis is a rare complication after cruciate ligament surgery. The lack of conclusive evidence makes it difficult to obtain a consensus concerning the best treatment option.

From June 1993 to May 2010, 31 patients met the inclusion criteria for this prospective case series. The average age at ACL injury was 33.5 years. Treatment protocol was based on the grade of infection. Options included arthroscopic treatment for infections of Gaechter grades 1 and 2 or arthrotomy for infections of grades 3 and 4. Graft retention was decided based on the clinical findings. The setting was a specialized trauma hospital. Follow-up included International Knee Documentation Committee (IKDC) forms, Tegner score, and Lysholm scores at a mean of six years (71 months; range, 13-140) after treatment.

In all cases, treatment of infection was successful; overall, a mean of 2.6 operations were required. In eight cases, it was possible to salvage the graft. The Tegner activity level before the knee injury was 6.5 points. At follow-up, the average score was 4.5 points. The postoperative subjective IKDC score averaged 63. The mean Lysholm score was 63.9. On clinical examination, a mean extension deficit of 2.5° and a mean maximum flexion of 121° were found. In the single-legged hop test, a mean capacity of 68% compared with the uninjured side was measured.

The stage-adapted procedure gives reliable results for septic arthritis after ACL surgery. There were no recurrences of septic arthritis or bone infection. Early infection can be managed arthroscopically with satisfactory results. More advanced infections should be addressed with a more radical approach. In conclusion, functional outcome in most of the presented cases was only fair compared with results from ACL surgery not complicated by infection.