Septic arthritis of the knee after anterior cruciate ligament surgery: a stage-adapted treatment regimen.

Background: Septic arthritis is a rare complication after anterior cruciate ligament surgery. All case series reported so far have been retrospective, and case numbers of septic arthritis have ranged from 4 to 11.

Hypothesis: A stage-adapted treatment regimen for septic arthritis after anterior cruciate ligament surgery can provide reliable results.

Study Design: Case series; Level of evidence, 4.

Methods: From June 1993 to May 2003, 24 patients met the inclusion criteria for this study. The average age at trauma was 32.5 years. Treatment protocol was based on the grade of infection. Options included transarthroscopic treatment for Gaechter grades 1 and 2 infections or medial and lateral arthrotomy for grades 3 and 4 infections. Graft retention was decided based on clinical findings. The setting was a specialized trauma hospital. Follow-up included International Knee Documentation Committee forms, radiographs, and the Tegner and Lysholm scores at a mean of 66 months (range, 11-142) after treatment.

Results: In all cases, treatment of infection was successful; overall, a mean of 2.2 operations were required. In 7 cases, it was possible to salvage the graft. The Tegner activity level before the knee injury was 6.1 points. At follow-up, the average score was 3.8 points. The postoperative subjective International Knee Documentation Committee score averaged 64. The mean Lysholm score was 65.6. On clinical examination, a mean extension deficit of 3 degrees and a mean maximum flexion of 120 degrees were found. In the single-legged hop test, a mean capacity of 63% compared with the uninjured side was measured.

Conclusion: The described treatment regimen gives reliable results for this complication. There were no recurrences of septic arthritis or bone infection. Early infection can be managed arthroscopically with satisfactory results regarding the treatment of infection. In advanced or chronic infection, a more radical approach seems favorable. Results in these cases are overall only fair compared with patients with an uncomplicated anterior cruciate ligament reconstruction.