Laminar airflow systems are universal in current orthopaedic operating theatres and are assumed to be associated with a lower risk of contamination of the surgical wound and subsequent early infection. Evidence to support their use is limited and sometimes conflicting. We investigated whether there were any differences in infection rates (deep and superficial) between knee and hip arthroplasty cases performed in non-laminar and laminar flow theatres at 10 year follow-up. Between 2002 and 2006, 318 patients underwent knee and hip arthroplasty in a non-laminar flow theatre. Prospectively collected local arthroplasty audit data was collected including superficial and deep infection, revision for infection and functional outcomes. A cohort of patients from the same time period, who underwent knee and hip arthroplasty in a laminar flow theatre, were matched for age, sex, body mass index (BMI), operative approach, implant and experience of surgeon. Superficial infection rates were lower overall in the non-laminar flow theatre (2.2percnt; versus 4.7percnt;), with a significantly lower superficial infection rate for knee arthroplasty performed in the non-laminar flow theatre (2percnt; versus 6.9percnt;). The deep infection rates were similar (1.3percnt; vs 1.9percnt;) for both laminar and non-laminar flow theatre respectively. Revision rates for infection were similar between both groups (0.9percnt; in non-laminar flow theatre vs 0.3percnt; in laminar flow). Whilst the causes of post-operative surgical site infection are multifactorial, our results demonstrate that at long –term follow-up, there was no increased risk of infection without laminar flow use in our theatre

Purpose: Although few theatres have been equipped in France, integrated horizontal laminar airflow with air flowing in from the entire surface of one wall and flowing out through the contralateral wall is the most favourable installation for orthopaedic surgery. We had the opportunity to work in two theatres installed in 1980 with the construction of a new hospital. The objectives were to: 1) resolve the problem of airborne biocontamination of our aseptic rooms (excepting the complete isolation unit for septic patients), 2) allow intensive use of both horizontal airflow operative theatres considering the authorized budget was 2.5 aseptic rooms for 90 beds and approximately 400000 K annually (K=surgery cost-unit reimbursed by the national health insurance fund), 3) enable more favourable personnel movement and material handling than vertical flow systems where the operative surface is limited and the risk of dust accumulation is high, for indications we considered particularly important (targeted orthopaedic procedures: hip surgery for example). In addition, it appeared advisable to have repairs performed outside the operative unit, a possibility proposed with the Luwa system (Zurich, Switzerland). Material and methods: The floor surface area of each of the theatres is 34 m2 for a 99 m3 volume. One entire wall (the wall opposite the entrance for patients and surgeons) emits the horizontal laminar airflow. Air flows out through captors on the opposite wall next to the doors and is recycled. Airflow rate is greater than 0.25 m/s maintaining laminar flow throughout the theatre (anemometric measurements). The hygrometry can be controlled. Filtration removes all particles measuring 0.2 mm or larger. The temperature is maintained at 20° maximum. The entire air volume is renewed 600 times per hour. Overpressure is maintained permanently (manometric measurements) and can be controlled manually every day (first approximation). Results: 1. Aeraulic quality controls were performed by a non-specialized nurse. Intensive use was maintained for more than 15 years. Parameters were controlled after installation then every six months (during non-active periods). Essential material included a particle counter (graduated in cubic feet) which showed we were situated at a level below class 100 (Fed US 209 D). Anomalies observed several times (localised particle ascension) were related to filter dysfunctions. The ‘holes’ were eliminated by changing filters. Other parameters were maintained with no problem. The only change occurred in one of the theatres where airflow was considered to be insufficient at the end of the theatre and a defective outflow was removed; because of these changes, inflow had to be readjusted and the door occlusions had to be changed; later quality controls were favourable. Activity level was not monitored with sufficient precision to take into consideration. 2. The rate of clinical infections associated with these theatres was maintained very low but antibiotic prophylaxy was continued. Discussion: The objectives we set for these theatres have been achieved. This type of installation is very superior to vertical flow suggesting we should equip future theatres with this type of system

To compare the number of airborne bacteria and particles under laminar airflow (LAF) versus turbulent airflow (TAF) with 100% and 50% reduced fresh air exchange during simulated total hip arthroplasty (THA). Two equally dimensioned operating rooms (OR) build in 2009 with modern ventilation systems of LAF and TAF respectively were used during 32 simulated THA-operations under four different ventilation conditions: LAF or TAF with either full (n=8+8) or 50% reduced (n=8+8) fresh air exchange volume. We followed a protocol controlling the complete perioperative setup including interior cleaning, sterile materials, OR-personnel procedures, surgical clothing, instruments and 50-minute surgical procedure on a full-sized dummy at 37°C. Microbial contamination was determined intra-operatively by ISO-validated Microbiological Active Sampler (MAS-100, Merck, 100 L/min) at two 10-minute intervals in 30 cm distance of the operating field. Blood-agar plates from each operation were incubated for 2 days at 35°C and the microbial concentration was determined by viable counting of colony-forming units (CFU) per m3 air. Furthermore airborne particulate (0,5–10 µm) was sampled with ISO-validated light scattering particle analyzer (MET-one, Beckman Coulter, 28,3 L/min) during the 50-minute surgical procedure (1,42 m3/operation). Large particle sizes (>5 µm) are correlated with microbial contamination (Stocks, 2010). According to standards large-sized particle number must not exceed a 2.900/m3-threshold for cleanroom operations. Microbial air concentration (mean CFU/m3 ±standard deviation) under LAF conditions with full and 50% reduced fresh air exchange were 0,4±0,8 and 0,4±0,4 respectively, whereas air contamination under TAF conditions were significantly higher with 7,6±2,0 and 10,3±8,1 (p<0,05). Large (>5 µm) airborne particulate (mean no./m3 ±standard deviation) under LAF conditions with full and 50% reduced fresh air exchange were 1.581±2.841 and 1.018±1.084 respectively, whereas particulate under TAF conditions were 7.923±5.151 and 6.157±2.439 respectively. Microbial air contamination was significantly lower under LAF ventilation compared to TAF during simulated THA under both full and 50% reduced fresh air exchange in modern operating theatres used in daily clinic. The number of particles measured under TAF conditions exceeded the threshold for cleanroom operations in 12/16 simulated operations. These findings indicate that LAF reduces the airborne microbial risk factor of surgical site infection in comparison to TAF

Objectives. During open orthopaedic surgery, joints may be exposed to air, potentially leading to cartilage drying and chondrocyte death, however, the long-term effects of joint drying in vivo are poorly understood. We used an animal model to investigate the subsequent effects of joint drying on cartilage and chondrocytes. Methods. The patellar groove of anaesthetised rats was exposed (sham-operated), or exposed and then subjected to laminar airflow (0.25m/s; 60 minutes) before wounds were sutured and animals recovered. Animals were monitored for up to eight weeks and then sacrificed. Cartilage and chondrocyte properties were studied by histology and confocal microscopy, respectively. Results. Joint drying caused extensive chondrocyte death within the superficial regions of cartilage. Histology of dried cartilage demonstrated a loss of surface integrity at four weeks, fibrillations at eight weeks, and an increased modified Mankin score (p < 0.001). Cartilage thickness increased (p < 0.001), whereas chondrocyte density decreased at four weeks (p < 0.001), but then increased towards sham-operated levels (p < 0.01) at eight weeks. By week eight, chondrocyte pairing/clustering and cell volume increased (p < 0.05; p < 0.001, respectively). Conclusions. These in vivo results demonstrated for the first time that as a result of laminar airflow, cartilage degeneration occurred which has characteristics similar to those seen in early osteoarthritis. Maintenance of adequate cartilage hydration during open orthopaedic surgery is therefore of paramount importance. Cite this article: Dr A. Hall. Drying of open animal joints in vivo subsequently causes cartilage degeneration. Bone Joint Res 2016;5:137–144. DOI: 10.1302/2046-3758.54.2000594

Aims. The interaction between surgical lighting and laminar airflow is poorly understood. We undertook an experiment to identify any effect contemporary surgical lights have on laminar flow and recommend practical strategies to limit any negative effects. Materials and Methods. Neutrally buoyant bubbles were introduced into the surgical field of a simulated setup for a routine total knee arthroplasty in a laminar flow theatre. Patterns of airflow were observed and the number of bubbles remaining above the surgical field over time identified. Five different lighting configurations were assessed. Data were analysed using simple linear regression after logarithmic transformation. Results. In the absence of surgical lights, laminar airflow was observed, bubbles were cleared rapidly and did not accumulate. If lights were placed above the surgical field laminar airflow was abolished and bubbles rose from the surgical field to the lights then circulated back to the surgical field. The value of the decay parameter (slope) of the two setups differed significantly; no light (b = -1.589) versus one light (b = -0.1273, p < 0.001). Two lights touching (b = -0.1191) above the surgical field had a similar effect to that of a single light (p = 0. 2719). Two lights positioned by arms outstretched had a similar effect (b = -0.1204) to two lights touching (p = 0.998) and one light (p = 0.444). When lights were separated widely (160 cm), laminar airflow was observed but the rate of clearance of the bubbles remained slower (b = -1.1165) than with no lights present (p = 0.004). . Conclusion. Surgical lights have a significantly negative effect on laminar airflow. Lights should be positioned as far away as practicable from the surgical field to limit this effect. Cite this article: Bone Joint J 2017;99-B:1061–6

Patient warming significantly decreases the risk of surgical site infection. Recently there have been concerns that forced air warming may interfere with unidirectional airflow, potentially posing an increased risk of infection. Our null hypothesis was that forced air and radiant warming devices do not increase the temperature and the number of particles over the surgical site when compared with no warming device. A forced air warming device was compared with a radiant warming device and no warming device as a control. The temperature and number of particles were measured over the surgical site. The theatre was prepared as for a routine lower-limb arthroplasty operation, and the same volunteer was used throughout the study.

Forced air warming resulted in a significant mean increase in the temperature (1.1°C vs 0.4°C, p < 0.0001) and number of particles (1038.2 vs 274.8, p = 0.0087) over the surgical site when compared with radiant warming, which raises concern as bacteria are known to require particles for transport.

We have recently shown that waste heat from forced-air warming blankets can increase the temperature and concentration of airborne particles over the surgical site. The mechanism for the increased concentration of particles and their site of origin remained unclear. We therefore attempted to visualise the airflow in theatre over a simulated total knee replacement using neutral-buoyancy helium bubbles. Particles were created using a Rocket PS23 smoke machine positioned below the operating table, a potential area of contamination. The same theatre set-up, warming devices and controls were used as in our previous study. This demonstrated that waste heat from the poorly insulated forced-air warming blanket increased the air temperature on the surgical side of the drape by > 5°C. This created convection currents that rose against the downward unidirectional airflow, causing turbulence over the patient. The convection currents increased the particle concentration 1000-fold (2 174 000 particles/m³ for forced-air warming vs 1000 particles/m³ for radiant warming and 2000 particles/m³ for the control) by drawing potentially contaminated particles from below the operating table into the surgical site.

Cite this article: Bone Joint J 2013;95-B:407–10.

Aim. Whether laminar airflow (LAF) in the operating room (OR) is effective for decreasing periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) remains a clinically significant yet controversial issue. This study investigated the association between operating room ventilation systems and the risk of PJI in TJA patients. Method. We performed a retrospective observational study on consecutive patients undergoing primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) from January 2013-September 2017 in two surgical facilities within a single institution, with a minimum 1-year follow-up. All procedures were performed by five board-certified arthroplasty surgeons. The operating rooms at the facilities were equipped with LAF and turbulent ventilation systems, respectively. Patient characteristics were extracted from clinical records. PJI was defined according to Musculoskeletal Infection Society criteria within 1-year of the index arthroplasty. A multivariate logistic regression model was performed to explore the association between LAF and risk of 1-year PJI, and then a sensitivity analysis using propensity score matching (PSM) was performed to further validate the findings. Results. A total of 6,972 patients (2,797 TKA, 4,175 THA) were included. The incidence of PJI within 1 year for patients from the facility without laminar flow was similar at 0·4% to that of patients from the facility with laminar flow at 0·5%. In the multivariate logistic regression analysis, after all confounding factors were taken into account, the use of LAF was not significantly associated with reduction of the risk of PJI. After propensity score matching, there was no significant difference in the incidence of PJI within 1 year for patients between the two sites. Conclusions. The use of LAF in the operating room was not associated with a reduced incidence of PJI following primary TJA. With an appropriate perioperative protocol for infection prevention, LAF does not seem to play a protective role in PJI prevention

Introduction: Since the introduction of joint arthroplasty major advances including the introduction of laminar airflow, have been made in reducing infection to current rates of 1 to 2%. Nonetheless infection remains a devastating complication, with major implications in terms of patient suffering, duration of hospital stay and financial burden. We undertook a study to examine the incidence of bacterial wound contamination occurring in the intra-operative period. Materials and Methods: All patients admitted to our unit for elective hip and knee arthroplasty were entered into the study. On arrival in theatre a skin swab was taken. The patient was then prepared and draped in the anaesthetic room before final draping by the surgical team in the operating theatre. All procedures were performed in theatres equipped with laminar airflow, and all surgical personnel wore isolator suits. During the course of the procedure swabs were taken from the anterior aspect of the femur at 30-minute intervals. In addition the skin and inside blades and the suction tip were harvested at the end of the procedure. All samples were then sent for culture. Patient data including age, comorbid conditions and history of previous surgery were noted on a standardised pro forma. In addition, operative data including duration of the procedure, operating surgeon and type of drape and skin preparation used were noted. Results: 65 patients have been examined to date. An incidence of contamination of 14% has been noted (9 patients) with the skin blade and suction tip being the most common source of contaminating organisms. Staphylococcus epidermis was cultured in 5 cases, with Gram negative organisms being cultured in the remaining samples. In all 9 cases only small numbers of organisms were identified. None of the patients with positive cultures developed clinical signs of deep or superficial wound sepsis, and all had an uncomplicated postoperative course. Conclusions: While low levels of contamination are unavoidable in theatre, it is important that strict discipline be maintained in order to minimise this risk. In particular, careful attention to patient skin preparation, the use of prophylactic antibiotics and minimising use of the suction tubing help decrease contamination rates

Literature debates whether fluid aspirates for suspected PJI should undergo prolonged incubation for cultures. We looked at sensitivity and specificity of 14-day cultures, compared to 7-days, for aspirates from prosthetic hips and knees. Design and methods. Conducted at a quaternary referral centre for PJIs from Jan 2017 to July 2019. Suspected PJIs who underwent aspiration, incubated 14 days and later surgical intervention with minimum three tissue samples were included. Results. 176 aspirates were included. This is an increased number compared to our historic figures (average 88 Vs 48 pts/yr). 47 patients had fluid and tissue positive (true positive), 20 fluid +ive but tissue -ive (false positive), 98 fluid and tissue -ive (true negative) and 15 fluid negative but tissue +ive (False negative). Thus, sensitivity 76%, specificity 83%, positive predictive value70% and negative predictive value 87%. Of 88 positive aspirates, only 75% were within 7-day cultures. Low virulence organisms as Propionibacterium acnes and coagulase negative staph were grown later. Of 48 with only one tissue sample positive, 38 were culture-negative on aspiration and 6 grew different organisms on aspirate and tissues. Also, as many were cultured later, it suggests contamination. Conclusion. Increased numbers reflect quaternary referral nature of institution and increasing PJI load. Modest drop in sensitivity and specificity of 14-day cultures compared to 7-day(84 and 85% respectively) is due to higher false negatives. Contamination contributes to false-ive as more tissue samples become positive (there were 1076 tissue samples due to multiple sampling Vs 176 aspirates). Higher tissue yield may also be because they are more representative. Effect of antibiotic use between samples cannot be determined. Organism profile suggest14-day culture produces more contaminant growth despite a well-equipped microbiology lab with laminar airflow for subcultures. Caution in interpreting 14-day results in diagnosis of PJI of Hip and Knee is advised

Aim. The aim of this study was to validate the information on operating room ventilation reported to the Norwegian Arthroplasty Register (NAR) and to assess the influence of this ventilation on the risk of revision due to infection after primary total hip arthroplasty (THA). Method. Current and previous ventilation systems were evaluated together with the hospitals head engineer in 40 orthopaedic hospitals. The ventilation system of each operating room was assessed and confirmed as either conventional ventilation, vertical laminar airflow (LAF) or horizontal LAF. We then identified cases of first revision due to deep infection after primary THA and the type of ventilation system reported to the NAR in the period 1987–2014. The association between revision due to infection and operating room ventilation was estimated by relative risks (RR) in a Cox regression model. Results. 103370 primary THAs and 971 (0.9%) first revisions due to deep infection were reported. 51% of the primary THAs were performed in a room with vertical LAF, 44% in a room with conventional ventilation and 5% in a room with horizontal LAF. There was a mean misreporting rate of approximately 12%. There was similar risk of revision due to infection after THA performed in operating rooms with vertical laminar air flow compared to conventional ventilation (RR=0.95, 95 % CI: 0.8–1.1) and an increased risk of revision due to infection after THA performed in horizontal LAF conditions compared to conventionally ventilated conditions (RR=1.3, 95 % CI: 1.0–1.7). Conclusions. Surgeons are not fully aware of what kind of ventilation there is in the operating room. This study may indicate that vertical LAF is not superior to conventional ventilation concerning reduction of THA infection, and therefore does not justify any increased installation costs. Also, horizontal LAF systems appear to be inferior to other ventilation systems

The aim of this study was to validate the information on operating room ventilation reported to the Norwegian Arthroplasty Register (NAR). We then wanted to assess the influence of operating room ventilation on the rate of revision due to infection after primary THA performed in operating rooms with conventional ventilation, “greenhouse”–ventilation and Laminar Airflow ventilation (LAF). We identified cases of THA revisions due to deep infection and the type of ventilation system reported to the NAR from the primary THA. We included 5 orthopaedic units reporting 17947 primary THAs and 136 (0.8%) revisions due to infection during the 28 year inclusion period from 1987 to 2014. The hospitals were visited and the current and previous ventilation systems were evaluated together with the hospitals head engineer, and the factual ventilation on the specific operating rooms was thereby assessed. The association between revision due to infection and operating room ventilation was estimated by calculating relative risks (RR) in a Cox regression model. 73% of the primary THAs were performed in a room with LAF, in contrast to the reported 80 % of LAF. There was similar risk of revision due to infection after THA performed in operating rooms with laminar air flow compared to conventional ventilation (RR=0.7, 95 % CI: 0.2–2.3) and after THA performed in operating rooms with “greenhouse”-ventilation compared to conventional ventilation (RR=1.2, 0.1–11). Surgeons are not fully aware of what kind of ventilation there is in the operating room. This study may indicate that, concerning reduction in incidence of THA infection, LAF does not justify the substantial installation cost. The numbers in the present study are too small to conclude strongly. Therefore, the study will be expanded to include all hospitals reporting to the NAR

Aim: This study aimed at investigating the diagnostic value of local anaesthetic hip injection test to differentiate between hip and spinal pain in patients presenting with symptoms attributable to both hip and spine pathology. Study design: Prospective cohort. Materials and Methods: 48 patients with such diagnostic dilemma under one the care of one spinal surgeon in one centre were carefully selected. All patients had radiographs of the hip joint confirming varying degrees of osteoarthritis. Most of the patients also had different types of spinal imaging showing degenerative spinal changes. The hip injection test involved intraarticular injection of 0.5% Bupivacaine under strict aseptic precautions in a laminar airflow theatre under fluoroscopic control. Results: 37 patients had a significant relief of pain to the injection. Of these, 33 (89%) underwent successful total hip replacement with relief of pain. The patients with a negative response to the test responded satisfactorily to treatment directed towards their spinal pathology. The sensitivity of this test is at least 97% and specificity 90%. These results are similar to those of previous studies on this topic. Conclusion: Local anaesthetic hip injection test is a safe, inexpensive and reliable diagnostic tool in identifying the source of the pain in patients with attributable dual pathology

We conducted a randomized controlled trial (RCT) to investigate if iodine impregnated incision drapes (IIID) increases bacterial recolonization rates compared to no drape use under conditions of simulated total knee arthroplasty (TKA) surgery. Background: To prevent surgical site infection (SSI), one of the important issues is managing the patient´s own skin flora. Many prophylactic initiatives have been suggested, including the use of IIID. IIID has been debated for many years and was deemed ineffective in preventing SSI in a recent systematic review [1], while some evidence suggests a potential increase in postoperative infection risk, as a result of IIID use [2]. IIID is sparsely investigated in orthopaedic surgery. An increase in the number of viable bacteria in the surgical field of an arthroplasty operation has a potential to increase the risk of SSI in an otherwise elective and clean procedure [3]. 20 patients scheduled for TKA were recruited. Each patient had one knee randomized for draping with IIID [4] while the contralateral knee was left bare, thus the patients acted as their own controls. Operating theater settings with laminar airflow and standard perioperative procedures were simulated. Sampling was performed with the cup-scrup technique [5] using appropriate neutralizers. Samples were collected from the skin of each knee prior to disinfection and on 2 occasions after skin-preparation, 75 minutes apart. Bacterial quantities were estimated by spread plating with 48-hour aerobic incubation. Outcome was measured as colony forming units per square centimeter of skin. We used Wilcoxon signed-rank test for comparative analysis within and between knees. Following skin-disinfection we found no significant difference in bacterial quantities between the intervention and the control knee (p = 0.388). Neither did we see any difference in bacterial quantities between the two groups after 75 minutes of simulated surgery (p = 0.367). When analyzed within the intervention and control group, bacterial quantities had not significantly increased at the end of surgery when compared to baseline, thus no recolonization was detected (p = 0.665 and 0.609, respectively). Iodine impregnated incision drapes did not increase bacterial recolonization rates in simulated TKA surgery. Thus, the results of this RCT study does not support the hypothesis that iodine impregnated incision drapes promotes bacterial recolonization and postoperative infection risk

Introduction: Surgical Site Infection (SSI) in spinal surgery at the James Cook University Hospital was investigated and compared with the published rates of 1 – 12%. Variables of instrumentation, laminar air flow, duration of operation, and blood units transfused in the first 48 hours were examined. Methods: 556 spinal operations were carried out in 2005–6. 147 of these involved the use of instrumentation. Infections were defined as positive wound or blood cultures. The duration of surgery, presence of laminar air flow and units of blood transfused were recorded. Statistical analysis was performed using Fishers exact test. Results: 9 cases of SSI were identified in the 147 instrumented spinal operations in comparison to zero in the 409 non-instrumented patients (p < 0.0001). The mean duration of surgery was 4 hours 19mins. The results for operation duration < 5hours vs. operation duration > 5hours (3/96 vs 6/51) were not statistically significant. (p=0.065). Of the 147 instrumented spinal operations, 8 of the infected were performed in a laminar air flow system and 1 without (not statistically significant, p=0.69). The results for blood transfusion < 2units vs. blood transfusion ≥2 units (4/85 vs 5/62) were not significant (P=0.49). Conclusion: The rate of SSI at the James Cook University Hospital in instrumented spinal surgery was 6%. SSI in spinal surgery was heavily influenced by instrumentation, but was not reduced by laminar airflow. Duration of operation and number of units of blood transfused were not significant factors

Introduction. Infection is disastrous in arthroplasty surgery and requires multidisciplinary treatment and debilitating revision surgery. Between 80-90% of bacterial wound contaminants originate from colony forming units (CFUs) present in operating room air, originating from bacteria shed by personnel present in the operating environment. Steps to reduce bacterial shedding should reduce wound contamination. These steps include the use of unidirectional laminar airflow systems and the introduction of theatre attire modelled on this principle (e.g. total body exhaust suits). Our unit introduced the use of the Stryker Sterishield Personal Protection System helmet used with laminar flow theatre systems. This study compares an enclosed helmet system used with standard gowns, with standard hood and mask attire. Method. 12 simulated hip arthroplasties were performed, six using disposable sterile impermeable gown, hood and mask and a further 6 using a Sterishield helmet and hood. Each 20 minute operation consisted of arm and head movements simulating movements during surgery. Air was sampled at wound level on a sterile draped operating table using a Casella slit sampler, sampling at 700l/minute. Samples were incubated on Blood agar for 48 hours at 37°c and the CFUs grown were counted. Results. Mean number of CFUs for the helmet was 9.33 with hood and mask attire having 49.16 CFUs (S. Ds 6.34 and 26.17; p value 0.0126). In all cases a coagulase negative staphylococcus was isolated. Conclusion. Although the sample size was small, we demonstrated a fivefold increase in the number of CFUs shed when using hood and mask attire compared to personal helmet and sterile hood. We conclude that the helmet system is superior to non-sterile hood and mask at reducing bacterial shedding by theatre personnel

Introduction: Surgical Site Infection (SSI) in spinal surgery at the James Cook University Hospital was investigated and compared with the published rates of 1–12%. Variables of instrumentation, laminar air flow, duration of operation, and blood units transfused in the first 48 hours were examined. Methods: 556 spinal operations were carried out in 2005–6. 147 of these involved the use of instrumentation. Infections were defined as positive wound or blood cultures. The duration of surgery, presence of laminar air flow and units of blood transfused were recorded. Statistical analysis was performed using the Fisher’s Exact Test. Results: Nine cases of SSI were identified in the 147 instrumented spinal operations in comparison to Zero in the 409 non-instrumented patients (p < 0.0001). The mean duration of instrumented surgery was 4 hours 19mins. The infection rates for operation duration < 5 h versus operation duration > 5 h (3/96 Vs 6/51) were not statistically significant (p = 0.065). Of the 147 instrumented spinal operations, 8 of 117 operations performed in a laminar air flow system and 1 of 30 performed without laminar air flow were infected (p = 0.69). Infection rates for those patients transfused < 2 units (4/85) were not significantly different to those in patients transfused > 2 units (5/62), p = 0.49. Conclusion: The rate of SSI at the James Cook University Hospital in instrumented spinal surgery was 6%. SSI in spinal surgery was heavily influenced by instrumentation, but was not reduced by laminar airflow. Duration of operation and number of units of blood transfused were not significant factors

Purpose: Infection after TJA is a rare but devastating complication. Horizontal laminar airflow has been advocated to reduce infection rate. Methods: 896 consecutive primary and revision total joint arthroplasties of the hip and knee were retrospectively reviewed. The first 751 were performed before February 2004 in a horizontal laminar air flow room; the final 146 were performed without laminar flow from February 2004 through May 2005. All patients received the same perioperative antibiotics, wound management, and rehabilitation program. Body exhaust systems were worn in all cases. Results: There were a total of 10 infections (1.1%) requiring surgical treatment, including 6 deep knee infections (0.67%), and four (0.45%) wounds (3 knees and 1 hip) with delayed healing or superficial infections. 9 of the infections occurred in the laminar flow group (1.2%), including all 6 deep knee infections (6/456=1.3%), 2 knee and 1 hip wound infection. Only 1 infection (0.68%), in a knee wound, occurred in the non-laminar flow group. There were no deep hip infections. Statistically, more knees became infected than hips overall (9/550=1.64% vs 1/346=0.29%)(p< 0.01) and more knees developed deep infection with laminar flow than without (6/456=1.2% vs 0/94=0.00%)(p< 0.1). Conclusions: Laminar air flow did not alter the infection rate in THA, but may have increased infection rate in TKA. Infection is multifactorial, and longer follow up of the non-laminar flow group may reduce the differences seen. Nevertheless, this data agrees with other published data and is of significant concern for the TKA surgeon and patient alike

The effects of infection following implantation of an orthopaedic prosthesis are devastating. The prevention of perioperative contamination is therfore of the utmost importance in arthroplasty. We undertook a prospective study to assess bacterial contamination in elective arthroplasty surgery. Splash bowls containing sterile saline are used to store and clean instruments used during the course of a procedure. The incidence of bacterial proliferation in splash bowls was examined as a marker of intra-operative contamination. A 100mL aliquot of fluid was removed from the splash basin at the end of the procedure and passed through a grid membrane using a vacuum pump. The membrane filter was then plated on chocolate agar and colony counts recorded at 24 and 48 hours. Organisms were identified by standard techniques. Demographic data, and perioperative data including the duration and type of procedure, the number of scrubbed and other personnel in theatre and the type of skin preparation and gowns used were also noted. A total of 43 cases were examined. 14 samples yielded positive cultures. Staphylcoccus was the most commonly cultured organism (9 cases). Four patients grew Pseudomonas species. Five patients grew other Gram-negative organisms including Neisseria and bacillus subspecies. Five patients grew multiple organisms. Mean duration of follow up was 8.4 months (range 6 – 18 months). None of the patients with contaminated samples developed any clinical signs of infection in the perioperative period; nor was there clinical or radiological evidence of infection or loosening on subsequent follow up. Despite the use of a laminar airflow system in all cases, in excess of 30% of cases were contaminated. This study underlines the importance of adhering to rigorous protocol in theatre including minimising theatre traffic and the use of antibiotic prophylaxis

The purpose of this study was to assess if the use of sterile stockings in lower limb surgery results in the contamination of the operative site with skin commensals from unprepared skin. Twenty-five consecutive patients under going elective single knee arthroscopy were included in our study. All patients were operated on in the same laminar airflow theatre, by the same surgeon using the same method of skin preparation and operative technique. Skin swabs were taken from each patient’s foot prior to the commencement of surgery. The limb was then prepared as follows;. An unscrubbed assistant holds up the leg, the leg is then prepared with betadine, by the surgeon from ankle to thigh, sparing the foot. The surgeon then towels off the thigh. The surgeon with the stocking in his hand, then takes hold of the foot using the stocking and unrolls it over the foot and up the leg. The stocking is bandaged in place and surgery commences. Two samples were also cut from the cuff of the stocking, one prior to its use to act as a control and the other once it had been unrolled up the leg. The three samples were then sent to microbiology. The swabs were plated out on blood (x2), chocolate and Maconkey agar. One blood plate was incubated anaerobically at 37°c and the others in air at the same temperature. The stocking sample was cultured in nutrient broth. After 48 hours isolates were identified using standard techniques. The results showed that none of the stocking samples yielded positive microbiology, however all of the foot swab samples did. They all grew coagulase negative Staphylococcus (CNS), five also grew conforms and one grew Pseudomonas, as well. We can conclude from this, that this method of skin preparation using the sterile stocking is safe. It appears in this study, that the action of unrolling the stocking over the unprepared foot and then up the prepared leg does not contaminate the prepared operative site with commensals from the foot. However concern is raised by the high incidence of CNS on the foot, and may be a source of potential infection