Prevention of pin site infection using a novel antimicrobial-impregnated collar

Walker, Jennie (2016) Prevention of pin site infection using a novel antimicrobial-impregnated collar. PhD thesis, University of Nottingham.

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Background and aims

Pin site infection (PSI) is a common complication of external fixation which can cause significant morbidity. Additional treatment required as a result of PSI can be costly in terms of NHS time and resources, but also personal and financial losses for those undergoing additional treatment. A reduction in PSI would therefore reduce the complications and costs associated with infection. The aim of the study is to determine the feasibility of antimicrobial impregnated collars in preventing PSI in patients with external fixation.


Current pin site care practices were identified by using an electronic questionnaire. Assessment of bacteria present at clinically non-infected and infected pin sites was determined through evaluating swabs obtained from the out-patient setting. Bacterial isolates were tested for antimicrobial sensitivity and biofilm capacity.

Pre-clinical testing of the antimicrobial collar used bacterial isolates identified from the PSI evaluation. Test strains included S aureus, S epidermidis, corynebacteria and E coli. Pre-clinical tests included SPTT, tK100, and an in-vitro pin site model.

A single-centre randomised control feasibility study was conducted with participants allocated to standard care or antimicrobial collar. Primary endpoints included number of participants with PSI, number of infected pin sites and bacteria present at pin sites at 3 months.

Main findings

Pin site care remains varied across the UK despite the availability of the UK Consensus Guidelines (Timms et al 2011). Pin site care is also inconsistent internationally. The bacterial evaluation identified large number of CoNS (46.2%), corynebacteria (10.7%) and S aureus (4.1%) in clinically non infected pin sites, although the significant increase of S aureus to 17.9% in PSI (p<0.01) suggests that this is a key causative organism in PSI.

Antimicrobial sensitivity testing identified that 91.9% CoNS were sensitive to at least two of the antimicrobials used in the collar indicating that the antimicrobial collar has the potential to prevent PSI. SPTT demonstrated the efficacy of the antimicrobial collar in maintaining a zone of bacterial inhibition in excess of three months. TK100 methods also demonstrated the ability of the antimicrobial collar to kill attached bacteria within 72 hours.

The feasibility study identified poor participant compliance with the antimicrobial collar. Participants in the antimicrobial collar group had significantly reduced bacteria at pin sites when the antimicrobial collar was retained in place for the duration of treatment (p=0.01). No significant difference was detected with number of participants with pin site infection or number of infected pin sites.


Results from preliminary testing indicates that the antimicrobial collar may be effective in reducing PSI in participants with external fixation, however further product development is required prior to rigorous testing with an adequately powered randomised control trial and economic evaluation.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Bayston, R.
Scammell, B.E.
Keywords: Orthopaedic; Infection; External fixation
Subjects: W Medicine and related subjects (NLM Classification) > WE Muscoskeletal system
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 32597
Depositing User: Walker, Jennie
Date Deposited: 19 Jul 2016 06:40
Last Modified: 02 May 2018 06:16

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