No difference in bacterial contamination of hip capsule sutures and control sutures in hip arthroplasty surgery

Abstract

Background: Perioperative preventive measures are important to further reduce the rate of periprosthetic joint infections (PJI) in patients undergoing total hip arthroplasty (THA). During THA surgery, joint capsule sutures are commonly placed to optimize exposure and reinsertion of the capsule. Bacterial contamination of these sutures during the procedure poses a potential risk for postoperative infection. In this exploratory study, we assessed the contamination rate of capsule sutures compared to the contamination of the remains of exchanged control sutures at the time of closure.

Methods: In 100 consecutive patients undergoing primary THA capsule sutures were exchanged by sterile sutures at the time of capsule closure. Both the original sutures and the remainder of the newly placed (control) sutures were retrieved, collected and cultured for ten days. Types of bacterial growth and contamination rates of both sutures were assessed.

Results: Sutures from 98 patients were successfully collected and analyzed. Bacterial growth was observed in 7/98 (7.1%) of the capsule sutures versus 6/98 (6.1%) of the control sutures, with a difference of 1% [CI -6-8]. There was no clear pattern in differences in subtypes of bacteria between groups.

Conclusions: This study showed that around 7% of capsule sutures used in primary THA were contaminated with bacteria and as such exchange by new sutures at the time of capsule closure could be an appealing PJI preventive measure. However, since similar contamination rates were encountered with mainly non-virulent bacteria for both suture groups, the PJI preventive effect of this measure appears to be minimal.

Keywords: Bacterial contamination; Capsule Sutures; Total hip arthroplasty.

Fig. 1

Posterolateral approach of the hip in THA and procedure of suture collection for microbiological culture. A: Exposed hip joint by reflecting the short external rotator muscles and the posterior joint capsule using capsule sutures (image is reproduced with permission from AO Surgery Reference;www.aosurgery.org); B: Hip joint exposed with capsule sutures in situ (• = piriformis tendon, ← = posterior capsule flap) held by a hemostat. Note that sutures are in contact with the surgical drape; C: After removal, original capsule sutures were placed in a sterile container filled with BHI broth; D: New, sterile sutures were used for capsule closure, and remains were collected in a separate sterile container