Background: Septic arthritis (SA) of the knee after anterior cruciate ligament reconstruction (ACLR) is a rare but potentially devastating condition. In certain cases, graft removal becomes necessary.
Purpose: To evaluate clinical, subjective, and radiologic outcomes of patients with SA after ACLR and assess whether graft retention has superior clinical results as compared with graft removal.
Study design: Cohort study; Level of evidence, 3.
Methods: All patients who were at least 12 months out from arthroscopic treatment of SA after isolated ACLR at our institution were eligible for inclusion. Patients were categorized into 2 groups: group 1, patients with initial graft retention; group 2, patients with initial graft removal. Group 2 was subdivided into 2 groups: group 2a, patients with graft reimplantation; group 2b, patients without graft reimplantation. Objective and subjective assessments were obtained at follow-up, including the International Knee Documentation Committee (IKDC) knee examination form, KT-1000 arthrometer measurements, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score, Lysholm score, and IKDC subjective evaluation. Radiologic assessment was performed with pre- and postoperative magnetic resonance imaging.
Results: Of the 41 patients included, 33 (81%) were available for follow-up at a mean ± SD 54.7 ± 24.4 months at an age of 28.4 ± 9.3 years. When compared with patients from group 2 (n = 12), patients from group 1 (n = 21) obtained significantly better results on the objective IKDC score (normal or nearly normal: group 1, 66.6%; group 2, 36.4%; P = .047) and KT-1000 measurements (group 1, 1.3 ± 1.0 mm; group 2, 2.9 ± 1.5 mm; P = .005). Group 1 also scored better than group 2 on the Lysholm ( P = .007), IKDC subjective ( P = .011), and WOMAC ( P = .069) measures. Between groups 2a (n = 4) and 2b (n = 8), no significant differences in outcomes could be detected ( P values, .307-.705), although patients with anterior cruciate ligament graft reimplantation showed a clear tendency toward better results in objective and not subjective parameters. Magnetic resonance imaging evaluation showed higher rates of cartilage damage and meniscal tears among patients with graft resection versus graft retention.
Conclusion: Patients with graft retention showed superior postoperative results when compared with patients who underwent initial graft resection, although subanalysis showed comparable outcomes between graft retention and reimplantation. Thus, while graft-retaining protocols should have the highest priority in the treatment of SA after ACLR, graft reimplantation should be performed in cases where graft resection becomes necessary, to avoid future cartilage and meniscal lesions. Finally, further studies with larger numbers of patients are needed to gain a better understanding of the outcomes of patients with SA after ACLR.
Keywords: ACL; anterior cruciate ligament reconstruction; graft removal; radiologic outcome; septic arthritis.