Bacterial Adherence to Barbed Monofilament Suture in a Contaminated Wound Model

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1 Bacterial Adherence to Barbed Monofilament Suture in a Contaminated Wound Model John R Fowler, MD Tiffany A Perkins, BS Bettina A Buttaro, PhD Allan L Truant, PhD Joseph S Torg, MD

2 Disclosures Funding provided by the John Lachman Orthopaedic Research Foundation

3 Background What type of absorbable suture should be used for subcutaneous layer closure? Braided Monofilament In the setting of infection?

4 Background 1937 Shambaugh and Dunphy Silk vs cat gut Contaminated wounds with feces and/or staph Silk closed wounds had less infection 1961 James and McLeod Implanted contaminated suture material subcutaneously into mice Nylon better than silk and cat gut

5 Background 1967 Alexander et al Compared braided and monofilament Placed contaminated suture material subcutaneoulsy in mice Monofilament overwhelmingly better

6 Background Barbed monofilament suture Allows knotless bi-directional wound closure Decreased operative time Tighter capsular closure Do the barbs make it act like a braided suture?

7 Purpose To determine how barbed monofilament suture performs in relation to four commonly used absorbable suture types Adherence of bacteria to each suture type Ability to culture bacteria after gentle washing Using confocal microscopy to examine the pattern of bacterial adherence

8 Materials and Methods Five suture materials Braided polyglactin 910(Vicryl, Ethicon) Braided antibacterial polyglactin 910 (Vicryl Plus, Ethicon) Monofilament polydiaxonone (PDS, Ethicon) Monofilament antibacterial polydiaxonone (PDS Plus, Ethicon) Barbed monofilament (Quill, Angiotech Pharm)

9 Materials and Methods Created a bacterial broth with MRSA 5 x CFU 1 x 10 5 CFU Elek et al (1957) and Krizek et al (1975) In normal host, need about 1 x 10 5 CFU for clinical infection

10 Materials and Methods Suture removed sterile from package, cut into 2 cm strips Incubated in MRSA broth for 5 minutes Suture removed with forceps, vortexed in 15 ml of normal saline for 10 seconds Vortex performed 0, 1, 2, 3, or 4 times Suture plated and incubated overnight

11 Materials and Methods Adherence Saline from the vortex plated and cultured CFU recorded from each plate Confocal Microscopy Suture incubated for 5 minutes Syto9 fluorescent DNA stain Laser confocal microscopy

12 Colony Forming Units Results High Bacteria Concentration polyglactin ,000 polydiaxonone barbed monofilament ,000 antibacterial polyglactin 910 antibacterial monofilament ,000 48, ,000 Suture Type Number of colony forming units (CFU) removed from the sutures after washing using high bacteria concentrations.

13 Colony Forming Units Results Low Bacteria Concentration Polyglactin 910 polydiaxonone barbed monofilament Suture Type Number of colony forming units (CFU) initially associating with the sutures after using physiologic bacterial concentrations. The bacteria dropped below the lower limit of detection (2 CFU/suture) after 1 wash.

14 Results Type of Suture Supraphysiologic Bacterial Concentration (CFU) Physiologic Bacterial Concentration (CFU) Polyglactin , Polydiaxonone monofilament 101, Barbed monofilament 48, Antibacterial polyglactin ,000 Antibacterial polydiaxonone 81,000 Difference between Quill (48,000) and Vicryl (213,000) statistically significant, p = 0.03

15 C Vicryl PDS Quill Vicryl Plus PDSPlus Unwashed 1 Wash 2 Washes 3 Washes 4 Washes

16 Polyglactin 910 Barbed monofilament

17 Polydiaxonone monofilament Antibacterial polydiaxonone monofilament

18 Discussion Barbed monofilament suture has shown benefit Cost savings Efficiency Tightness of closure Failure analysis Would be of benefit in revision total knee arthroplasty But is it safe to use if worried about infection?

19 Discussion Barbed monofilament suture demonstrated: Less bacterial adherence than braided polyglactin 910, comparable to monofilament polydiaxonone Less bacterial growth after vortex than braided polyglactin 910, comparable to monofilament polydiaxonone Confocal pattern more similar to polydiaxonone monofilament

20 Limitations In vivo model, may not translate well into clinical setting Only used one type of bacteria (MRSA) Length of incubation/vortexing may not accurately reflect clinical setting Physiologic bacterial loads unable to detect difference Only one brand of suture

21 Conclusion No increased bacterial adherence to barbed monofilament suture when compared to monofilament suture Further in vitro studies required to confirm these results Likely safe to use barbed monofilament suture in any wound that surgeon would have used monofilament