Septic knee arthritis following arthroscopy is a rare but dreaded complication: it might compromise patients’ functional prognosis and engage surgeon’s liability. This study analyzes the context of such infection occurrences, their management as well as their medicolegal consequences.

Twenty-two cases of knee septic arthritis following arthroscopy were examined during the medicolegal litigation process and collected for assessment from a medical liability specialised insurer. Half of the patients were manual workers who worked on their knees, and seven knees had a previous surgical history. The procedures performed at arthroscopy included seven ligamentoplasties, nine meniscotomies, three arthroscopic lavages, one arthrolysis, one chondroma removal and one plica resection. Seven patients, to some point, received corticosteroids: three preoperative joint injections, three intraoperative injections, and one oral corticotherapy.

Clinical signs of septic arthritis appeared after a median interval of 8 days (0–37), twice after a hemarthrosis and once after an articular burn. The median delay before treatment initiation was 4.2 days, and in 10 cases this therapeutic delay exceeded 3 days. On average, 3.5 additional procedures (1–9) were required to treat the infection and its residual sequels. Two total knee prostheses were implanted. Only two patients were free of disabling sequellae, and in five patients these sequels affected their livelihood. The medicolegal consequences were a partially permanent disability averaging 5% (0–20), a total temporary work incapacity of 120 days (40–790), a suffering burden averaging 3 out of 7 (0–4,5) points on the scale conventionally used in France. Twelve of these legal claims led to court ordered patient compensation.

Some risk factors of articular infection are known and well-identified. They can be linked to the patient’s condition (addiction to smoking, surgical history, professional activity) or to medical management (intra-articular corticoid injections, interventions under oral anticoagulants, inadvertently overheated irrigation fluid). When infection is suspected, it is often the needle-aspirated fluid’s inappropriate handling (such as absence of bacteriological testing or defective waiting time for the results), which delays the diagnostic or therapeutic management of this complication. All failures of infection diagnosis or treatment heavily contribute to malpractice claims against the surgeon. Early and appropriate management of postoperative infections helps limiting the risk of functional sequellae for the patient and reduces the risk of malpractice litigation for the practitioner.

Level IV; economic and decision analysis, retrospective study.