The microbiology of the infected arthroplasty would suggest that intra-operative contamination is the most common mechanism of the development of infection. The main source of contamination in joint replacement surgery is from the patients' skin and air-borne particles from theatre personnel.^3,4 The latter has been tackled by the development of ultra-clean air systems and developments in the type of garb worn by surgeons and their assistants. A number of studies have assessed the usefulness of surgical gowns and exhaust suits with regards to barrier function and protection afforded to healthcare workers from blood strike-through, splashes and aerosols.^5–7

One of the most efficient ways of reducing the bacterial load is to use a body exhaust suit such as that devised by Charnley (Fig. 1).⁸ However, many surgeons find the exhaust suit heavy and cumbersome. That, combined with high noise levels making communication difficult, has made the exhaust suit unpopular and many surgeons have abandoned its use.⁹

Figure 1 Sir John Charnley in his exhaust suit.

An alternative way of reducing the bacterial load is to use a sterile hooded helmet apparatus.¹⁰ This is either a loose-fitting hood or a hood combined with an integral gown which is known as a toga system.¹¹ They also protect surgical staff from blood splashes or aerosols and, by virtue of being sterile, do not contaminate any such splashes that may fall back into the operative area.

The Stryker Steri-Shield T4 helmet plus toga system (T4 Personal Protection System) is designed as a personal protection system (Fig. 2). It has the advantage of being light, portable and quiet. It also offers additional sterility to the head and neck region as compared to standard surgical attire or a conventional exhaust suit. No further facial splash protection such as visors or goggles are required. It has integral intake and exhaust fans built into the helmet which free the user from any cumbersome and restricting attachment to a vacuum system. Given these features, it has much to recommend its use over the standard Charnley body exhaust system, but as yet no study has addressed the relative levels of comfort and ease of using such systems.

Figure 2 Stryker Steri-Shield system.

The importance of objective outcome measures in medicine has been realised in recent years and many different scoring systems are currently used in a variety of settings.¹² Attempts to assess the comfort and protection afforded by surgical gowns have been made, but have been extremely simplistic and limited in their nature invariably relying on a single, subjective and unvalidated linear scoring system.^13,14 In this study, we have performed a comfort assessment comparison between the Charnley exhaust suit and the Stryker Steri-Shield system using a newly developed objective multidimensional validated ergonomic tool.

This prospective, comparative study was conducted in the four dedicated total joint arthroplasty theatres at Wrightington Hospital. Surgical staff were asked to complete a questionnaire at the end of either a total hip or knee primary arthroplasty operation after having worn either a disposable surgical gown plus mask with visor, a Charnley exhaust suit or a Stryker Steri-Shield system. No operation lasted more than 140 min or involved deviation from usual practice for primary or revision arthroplasty. The distribution and collection of questionnaires was undertaken by theatre nurse managers.

The questionnaire used in this study is a modification of the Comfort Rating Scale (CRS) designed to measure wearable comfort of computer devices during physical activity across 6 dimensions.¹⁵ These dimensions are emotion, attachment, harm, perceived change, movement and anxiety (Table 1). The different comfort dimensions or aspects were derived from multidimensional scaling statistical analysis of a term-by-term association matrix of 92 terms that described how wearing a device may affect the wearer or how the wearer may feel (physically and mentally) about the device.

Table 1 Comfort Rating Scale descriptors

We modified the CRS to be more specific for the wearing of theatre garb by changing the questions in each comfort dimension as shown in Table 2. This produced a modified CRS with a total of 11 questions as there are 3 questions each for the ‘perceived change’ and ‘physical effect’ dimensions and 2 questions for the ‘anxiety’ dimension. Each question was scored along a 20-point comfort rating scale which scored from 0 at the far left to 20 on the far right. This fulfils the criterion of Helander and Makund who recommend the use of 11 or more point scales for subjective evaluation.¹⁵ The scales were anchored at either end with the descriptors ‘0 = lowest’ and ‘20 = highest’. Using the scale simply requires that the scorer mark on the graduated line their level of agreement from low to high to the questions posed. Respondents were also asked to add a brief explanation for the score given.

Table 2 Modified Comfort Rating Scale

A mean score was calculated for each dimension. For dimensions that had more than one question, a mean was calculated for each question and then a mean calculated for the whole dimension.

Ten theatre staff were recruited to the study and completed the modified CRS on three separate occasions after having worn a disposable surgical gown plus mask with visor, a Charnley exhaust suit and a Stryker Steri-Shield system.

The total mean CRS for a disposable gown plus visor was 16.1 with a mean dimensional score of 2.7 (range, 0.2–8.4), for the Charnley system the values were 51.4 and 8.6 (range, 5.9–12.8), respectively, and for the Stryker Steri-Shield 15.4 and 2.6 (range, 0.8–5.6). Table 3 lists the dimensional scores and this is shown in chart form in Figure 3.

Table 3 Mean values of comfort dimensions for each clothing system (ranges in brackets)

Figure 3 Chart of comfort dimensions for each clothing system.

Comfort is a relative term which is usually determined by a combination of physiological, psychological and physical factors. Various factors such as poor fit, added weight or out-of-fashion style may make personal protective equipment (PPE) undesirable.¹⁶ A major limitation of comfort assessment studies is that they often score comfort along one scale implying that it is a one-dimensional construct. Just knowing that when wearing a device the wearer has a certain level of discomfort does not help in determining what aspect of the device makes the wearer feel uncomfortable. Comfort should be measured across a number of dimensions such as is possible with the Birmingham CRS. We realise that having made alterations to the original CRS that there may be attenuation of its validity, but the scale still remains much more objective than previous attempts at measurement of comfort of theatre garb.

One study has demonstrated that employees in a research institution, even those who were highly educated, failed to use their PPE.¹⁷ It was concluded that to make the workplace safer it is necessary to enhance the comfort, protective qualities and form or style of PPE. In the case of theatre garb for the scrub team, this translates into comfort and protection of the patient from contamination by the theatre team and protection of the scrub team from the patient's blood and tissue.¹⁸

This study has clearly demonstrated that over 6 dimensions of comfort measurement which include the criteria above that the use of a disposable, impermeable gown plus visor or the Steri-Shield system provide a system of PPE that is comfortable and comparable with both having almost similar modified CRS total scores. The greatest differences between the systems were in the ‘perceived change’ and ‘anxiety’ dimensions. The former was 8 times more comfortable for gowns than Steri-Shield whereas the latter was 8 times more comfortable for Steri-Shield than gowns.

Gowns offered the least hindrance to communication and vision, but were thought to offer little protection from strike-through, splashes or contamination of the sterile field from direct contact with the non-sterile visor or from tissue or fluid hitting the visor and then falling back into the wound. The Steri-Shield visor is sterile and the helmet and toga provide complete protection from the head down to the lower legs. Interestingly, although the order of magnitude of difference between all dimensions comparing gowns to Steri-Shield were similar, the actual ranges of values were much narrower for Steri-Shield (range, 0.8–5.6) than for disposable gowns (range, 0.2–8.4).

The Charnley exhaust system has proved to provide the least comfort with it being over 3 times more uncomfortable than either of the other PPEs assessed in this study using the modified CRS and may explain its poor uptake.⁹ It scores particularly badly in the dimensions of ‘attachment’ and ‘perceived change’ as it is not easy to don and is noisy. It also scores badly for ‘movement’ and ‘physical effect’ due to the weight and cumbersome nature of the exhaust tubes. Interestingly, it scores better than disposable gowns for ‘anxiety’ as it was felt to offer better protection and less chance of contamination, both of which are obvious concerns regarding PPE in the operating room.¹⁹

Although disposable, impermeable gown plus visor or the Steri-Shield system provide a similar level of comfort, the modified CRS has demonstrated that over 6 dimensions of measurable comfort the Steri-Shield system provides the least variation in comfort and as such may offer the best combination of comfort, protective qualities and form or style of PPE for lower limb arthroplasty operations.

The authors would like to thank the theatre staff at Wrightington Hospital who participated in this study for their time and effort.