Is nasal carriage of Staphylococcus aureus the main acquisition pathway for surgical-site infection in orthopaedic surgery?

The endogenous or exogenous origin of Staphylococcus aureus, responsible for orthopaedic surgical-site infections (SSI), remains debated. We conducted a multicentre prospective cohort study to analyse the respective part of exogenous contamination and endogenous self-inoculation by S. aureus during elective orthopaedic surgery. The nose of each consecutive patient was sampled before surgery. Strains of S. aureus isolated from the nose and the wound, in the case of SSI, were compared by antibiotypes or pulsed-field gel electrophoresis (PFGE). A total of 3,908 consecutive patients undergoing orthopaedic surgery were included. Seventy-seven patients developed an SSI (2%), including 22 related to S. aureus (0.6%). S. aureus was isolated from the nose of 790 patients (20.2%) at the time of surgery. In the multivariate analysis, S. aureus nasal carriage was found to be a risk factor for S. aureus SSI in orthopaedic surgery. However, only nine subjects exhibiting S. aureus SSI had been found to be carriers before surgery: when compared, three pairs of strains were considered to be different and six similar. In most cases of S. aureus SSI, either an endogenous origin could not be demonstrated or pre-operative nasal colonisation retrieved a strain that was different from the one recovered from the surgical site.

[Stabilization of the external condyle of the knee in chronic anterior laxity. Importance of the popliteal muscle]. / Stabilisation du condyle externe du genou dans les laxités antérieures chroniques. Importance du muscle poplité.

The authors have made an anatomical and experimental study in cadavers. They consider that one of the main features of chronic anterior instability of the knee is related to the instability of the lateral femoral condyle. This is due to the loss of its two stabilizers: the anterior cruciate ligament and the popliteal muscle. The signs of a lesion of the postero-lateral structures have to be looked for: antero-posterior drawer sign in extension, hypermobility of the tibia in lateral rotation and varus laxity. Such instability leads to arthrosis in the long-term. The proposed treatment is based on a reconstruction of the anterior cruciate ligament, using semitendinosus associated with a postero-lateral reconstruction using either the biceps or the fascia lata, or a free transplant from the patellar ligament. Corrective osteotomy of an associated varus deformity may be indicated.