High incidence of one-year stiffness and frequent secondary surgery after arthroscopic synovectomy for native knee septic arthritis - 18/08/26

Doi : 10.1016/j.otsr.2026.104864

Louis Idier ^a, Emma Abecidan ^a, Pierre-Alban Bouché ^b, Alexandre Hardy ^c, Christophe Ménigaux ^a, Thomas Bauer ^a, Charles Pioger ^a,⁎

^a Department of Orthopaedic Surgery, Ambroise Paré Hospital, AP-HP, 9 Avenue Charles De Gaulle, 92100 Boulogne-Billancourt, France

^b Department of Orthopaedic Surgery, Lariboisière Hospital, AP-HP, 2 Rue Ambroise Paré, 75010, Paris, France

^c Clinique du Sport Paris V, Ramsay Santé, Boulevard Saint-Marcel, 75005, Paris, France

^⁎ Corresponding author.

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Tuesday 18 August 2026

Abstract

Background

Native knee septic arthritis is commonly treated arthroscopically with the primary aim of infection eradication. However, the incidence of postoperative knee stiffness and the need for subsequent surgical procedures after successful treatment remain poorly defined.

Hypothesis

We hypothesized that, despite successful infection control, postoperative stiffness and the need for secondary surgical procedures represent frequent and clinically significant complications after arthroscopic treatment of native knee septic arthritis.

Methods

A retrospective single-centre cohort study was conducted including adult patients treated arthroscopically for culture-confirmed native knee septic arthritis between 2013 and 2022. Postoperative stiffness was defined as knee flexion ≤90 ° and/or extension deficit ≥10 ° at 1 year after infection eradication. Range of motion was assessed using standardized clinical goniometric measurements. Secondary outcomes included aseptic reoperations, arthrolysis, conversion to total knee arthroplasty, and Knee injury and Osteoarthritis Outcome Score (KOOS-12). Associations between patient-, infection-, and surgery-related variables and outcomes were analysed.

Results

Eighty-two patients met the inclusion criteria. Seventy-four had available 1-year follow-up data and were analysed for the primary outcome. Among these 74 patients, mean follow-up was 45.5 ± 28.4 months (range, 12–123). At 1 year, 45/74 patients (60.8%) met at least one stiffness criterion. Flexion ≤90 ° and extension deficit ≥10 ° occurred in 27/74 (36.5%) and 22/74 (29.7%), respectively. Mean flexion was 105.9 ° ± 16.8 (range, 60–130), and mean extension deficit was 4.9 ° ± 5.3 (range, 0–20). Aseptic reoperation was required in 28/74 patients (37.8%), including arthrolysis in 15/74 (20.3%) and total knee arthroplasty in 7/74 (9.5%). Kaplan–Meier aseptic-reoperation-free survival was 77.0% (95% CI, 65.7–85.0) at 12 months and 60.6% (95% CI, 48.1–70.9) at 45 months. Final KOOS-12 was significantly lower in patients with stiffness than in those without stiffness (65.3 ± 17.3 vs 80.0 ± 15.5; p < 0.001).

Conclusion

Postoperative stiffness is a frequent and clinically relevant complication following successful arthroscopic treatment of native knee septic arthritis. Successful infection eradication was not systematically synonymous with complete functional recovery, and secondary surgery was frequently required during follow-up.