What is the effect of reducing the air change rate on the ventilation effectiveness in ultra-clean operating rooms?

BACKGROUND: The operating room (OR) department is one of the most energy-intensive departments of a hospital. The majority of ORs in the Netherlands have an air-handling installation with an ultra-clean ventilation system. However, not all surgeries require an ultra-clean OR. AIM: To determine the effect of reducing the air change rate on the ventilation effectiveness in ultra-clean ORs. METHODS: Lower air volume ventilation effectiveness (VELv) of conventional ventilation (CV), controlled dilution ventilation (cDV), temperature-controlled airflow (TcAF) and unidirectional airflow (UDAF) systems were evaluated within a 4 × 4 m measuring grid of 1 × 1 m. The VELv was defined as the recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE). FINDINGS: The CV, cDVLv and TcAFLv ventilation systems showed a comparable mixing character in all areas (A, B and AB) when reducing the air change rate to 20/h. Ventilation effectiveness decreased when the air change rate was reduced, with the exception of the ACE. At all points for the UDAF-2Lv and at the centre point (C3) of the TcAFLv, higher RD10Lv and CRRLv were measured when compared with the other examined ventilation systems. CONCLUSIONS: The ventilation effectiveness decreased when an ultra-clean OR with an ultra-clean ventilation air-supply system was switched to an air change rate of 20/h. Reducing the air change rate in the OR from an ultra-clean OR to a generic OR will reduce the recovery degree (RD10) by a factor of 10-100 and the local air change rate (CRR) by between 42% and 81%.

Preoperative carbohydrate drink in fast-track primary total knee arthroplasty: a randomized controlled trial of 168 patients.

A key component in fast-track total knee arthroplasty (TKA) is early mobilization. Preoperative fasting might cause orthostatic hypotension and -intolerance which both can interfere with early mobilization. It was hypothesized that consuming a carbohydrate drink 2-3 hours prior to surgery is a viable option to reduce orthostatic hypotension, and as a result, improve rehabilitation. In this randomized controlled trial, all consecutive unilateral primary TKA patients were reviewed for eligibility. Exclusion criteria were American Society of Anesthesiologists (ASA) class above 3, older than 80 years of age, Diabetes Mellitus, and an insufficient comment of Dutch language. Patients were distributed in two groups. The control group was allowed to eat till 6 hours and drink clear fluids till 2 hours before surgery (standard treatment). The intervention group consumed, additionally to the standard treatment, a carbohydrate drink 2-3 hours before surgery. Blood pressure was measured both lying and standing as a measure for orthostatic hypotension during first time postoperative mobilization on day of surgery. A total of 168 patients were included. Prevalence of orthostatic hypotension in the control- and intervention group was 24 patients (34%) and 14 patients (19%) respectively, (p=0.05). Prevalence of orthostatic intolerance was 13 patients (19%) in the control group and 9 patients (13%) in the intervention group (p=0.32). No drink related adverse events occurred. In conclusion, taking a carbohydrate drink 2-3 hours before TKA significantly lowers the number of patients with orthostatic hypotension in early mobilization. However, the clinical relevance of the carbohydrate drink has to be studied further.

Prosthetic hip-associated cobalt toxicity: a systematic review of case series and case reports.

Prosthetic hip-associated cobalt toxicity (PHACT) is caused by elevated blood cobalt concentrations after hip arthroplasty. The aim of this study is to determine which symptoms are reported most frequently and in what type of bearing. We also try to determine the blood level of cobalt concentrations associated with toxicological symptoms. A systematic review was conducted on the 10th of July according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A methodological quality assessment (risk of bias (RoB)) was performed. Primary outcomes were the reported symptoms of cobalt toxicity and the level of cobalt concentrations in blood. These levels were associated with toxicological symptoms. A total of 7645 references were found of which 67 relevant reports describing 79 patients. The two most used bearings in which PHACT was described were metal-on-metal (MoM) bearings (38 cases) and revised (fractured) ceramic-on-ceramic (CoC) bearings where the former ceramic head was replaced by a metal head (32 cases). Of all reported symptoms, most were seen in the neurological system, of which 24% were in the sensory system and 19.3% were in central/peripheral system, followed by the cardiovascular (22.1%) system. The mean cobalt concentration for MoM-bearings was 123.7 ± 96.8 ppb and 1078.2 ± 1267.5 ppb for the revised fractured CoC-bearings. We recommend not to use a metal-based articulation in the revision of a fractured CoC bearing and suggest close follow-up with yearly blood cobalt concentration controls in patients with a MoM bearing or a revised fractured CoC bearing. Level of Evidence: Level V, systematic review.

Operating room ventilation systems: recovery degree, cleanliness recovery rate and air change effectiveness in an ultra-clean area.

BACKGROUND: Entrainment test methods are described in most European standards and guidelines to determine the protected area for ultra-clean ventilation (UCV) systems. New UCV systems, such as temperature-controlled airflow (TcAF) and controlled dilution ventilation (cDV) systems, claim the whole operating room (OR) to be ultra-clean. However, current test standards were not developed to assess ventilation effectiveness outside the standard protected area. AIM: To assess and compare the ventilation effectiveness of four types of OR ventilation systems in the ultra-clean area using a uniform test grid. METHODS: Ventilation effectiveness of four ventilation systems was evaluated for three different ultra-clean (protected) areas: the standard protected area (A); the area outside the standard protected area (B); and a large protected area (AB). Ventilation effectiveness was assessed using recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE). FINDINGS: RD, CRR and ACE were significantly higher for the unidirectional air flow (UDAF) system compared with the other systems in area A. In area B, the UDAF and cDV systems were comparable for RD and CRR, and the UDAF and conventional ventilation (CV) systems were comparable for ACE. In area AB, the UDAF and cDV systems were comparable for CRR and ACE, but significant differences were found in RD. CONCLUSION: In area A, the ventilation effectiveness of the UDAF system outperformed other ventilation systems. In area B, the cDV system was best, followed by the UDAF, TcAF and CV systems. In area AB, the UDAF system was best, followed by the cDV, TcAF and CV systems.

Long-term follow-up of distal radius fractures, an evaluation of the current guideline: the relation between malunion, osteoarthritis and functional outcome.

BACKGROUND: Last decades there is an increased tendency of performing surgery on displaced distal radius fractures. However, it is unclear whether this affects the development of osteoarthritis. This study aims to determine the relation between anatomical position, radiological osteoarthritis and functional outcome of the elderly wrist, 10-15 years after a distal radius fracture. PATIENTS AND METHODS: 173 patients between the age of 50 and 70 at time of trauma were included in this retrospective cohort study with a 10-15-year follow-up. Based on the reassessed initial X-rays, the patients were placed into 4 groups (1: anatomical, 2a: acceptable, 2b: current operative indication but treated conservative, 2c: operative indication and operated). Functional outcome was measured, questionnaires were answered, and new bilateral X-rays of the wrist were obtained. Factors influencing osteoarthritis, the difference in osteoarthritis between the groups and the difference between the fractured and non-fractured wrists were studied. RESULTS: Group 2b showed a significantly higher degree of osteoarthritis in comparison with the contralateral wrist. In the other groups, this difference was not observed. We found no significant difference in OA and functional outcomes between the groups. The degree of osteoarthritis of the non-fractured wrist appeared to be highly associated with osteoarthritis of the fractured wrist. CONCLUSION: The results of this study showed that the degree of radiocarpal osteoarthritis is higher in conservatively treated patients that should have been operated on according to current guidelines in comparison with patients without an indication for surgery. This might suggest that our current guidelines can be effective in prevention of posttraumatic osteoarthritis. However, the effect on the functional outcome is very limited. Since the degree of radiocarpal osteoarthritis of the non-fractured wrist appeared to be highly associated with the degree of osteoarthritis of the fractured wrist, future studies should always assess osteoarthritis of both wrists in order to study the real posttraumatic effect of a fracture.

Fast Starters, Slow Starters, and Late Dippers: Trajectories of Patient-Reported Outcomes After Total Hip Arthroplasty: Results from a Dutch Nationwide Database.

BACKGROUND: The purpose of this study was to explore whether subgroups of patients with different functional recovery trajectories after total hip arthroplasty can be discerned, as well as their predictors, using data from the Dutch Arthroplasty Register (Landelijke Registratie Orthopedische Implantaten [LROI]). METHODS: We retrospectively reviewed prospectively collected Oxford Hip Scores (OHS) up to 1 year postoperatively for patients who had undergone a primary total hip arthroplasty. Latent class growth modeling was used to classify subgroups of patients according to the trajectory of functional recovery represented by the patients' OHS. We used multivariable multinomial logistic regression analysis to explore factors associated with class membership. RESULTS: A total of 6,030 patients were analyzed. Latent class growth modeling identified fast starters (fast initial improvement, high 12-month scores; 87.7%), slow starters (no initial change and subsequent improvement; 4.6%), and late dippers (initial improvement and subsequent deterioration; 7.7%). Factors associated with slow starters were female sex (odds ratio [OR], 1.63 [95% confidence interval (CI), 1.14 to 2.33]) and smoking (OR, 1.95 [95% CI, 1.26 to 3.03]); an anterior approach (OR, 0.47 [95% CI, 0.29 to 0.78]) had a protective effect against a less favorable response. Factors associated with late dippers were age of >75 years (OR, 1.62 [95% CI, 1.22 to 2.15]), smoking (OR, 1.68 [95% CI, 1.17 to 2.42]), American Society of Anesthesiologists (ASA) grade of III or IV (OR, 1.41 [95% CI, 1.05 to 1.91]), obesity (OR, 1.96 [95% CI, 1.43 to 2.69]), poorer EuroQol-5 Dimensions (EQ-5D) Self-Care (OR, 1.41 [95% CI, 1.09 to 1.82] for "some problems" and OR, 2.90 [95% CI, 1.39 to 6.03] for "unable"), poorer EQ-5D Anxiety/Depression (OR, 1.31 [95% CI, 1.00 to 1.71] for "moderately" and OR, 1.86 [95% CI, 1.06 to 3.24] for "extremely"), poorer EQ-5D visual analog scale (OR, 0.91 [95% CI, 0.86 to 0.97] per 10 points), direct lateral approach (OR, 2.18 [95% CI, 1.58 to 3.02]), and hybrid fixation with a cemented acetabular implant (OR, 1.79 [95% CI, 1.00 to 3.21]). CONCLUSIONS: We discerned fast starters, slow starters, and late dippers after total hip arthroplasty. Female sex, older age, obesity, higher ASA grades, and worse EQ-5D scores were associated with a less favorable response to total hip arthroplasty, as well as hybrid fixation (cemented acetabular implant) and direct lateral approach. Anterior approach had a protective effect against a less favorable response. However, all subgroups experienced functional improvement following total hip arthroplasty. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Patient reported outcomes and implant survivorship after Total knee arthroplasty with the persona knee implant system: two year follow up.

BACKGROUND: More personalized implant designs for total knee arthroplasty might optimize the clinical outcome after surgery. One of these personalized implant designs is the Persona knee implant system (Zimmer Biomet, Warsaw, Indiana, USA). The primary objective of this study was to determine patient reported outcomes and implant survivorship of the Persona Knee system used in primary total knee arthroplasty, up to two years after surgery. METHODS: From November 2013 to July 2016 consecutive patients undergoing primary total knee arthroplasty were enrolled in a prospective observational cohort study at three centers. Preoperatively, at 6 weeks, 6 months, 1 and 2 years after surgery, patients completed the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), the Knee Society Score (KSS, 2011, modified version) and the EQ-5D. Adverse Events were captured, assessed for relationship to device, and recorded in the study database. Furthermore, physical functioning was assessed by the orthopedic surgeon. Repeated measures analyses were performed on PROM scores. Kaplan Meier was used to calculate survivorship of the Persona Knee Implant System. RESULTS: A total of 146 total knee arthroplasties were performed. 61% (89/146) of the patients were female and mean age was 64.7 (± 6.9) years. Two years after surgery, one patient had a revision of the polyethylene insert because of a periprosthetic joint infection. Therefore, the Kaplan-Meier survival estimate at 2 years was 0.99 (0.95-1.00 95% CI). OKS increased from 22.1 (95% CI 20.9-23.3) to 41.8 (95% CI 40.6-43.1) two years after surgery. Furthermore, all other PROMs also increased from before surgery to 2 year postoperatively. CONCLUSION: The Persona Knee implant is safe and effective and the clinical results up to two years after surgery are promising. PROMs results are very good; pain, function and quality of life all improved greatly after TKA. Further studies are needed to determine the long term clinical performance of the Persona prosthesis. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT02337244 ). Registered June 1st, 2015. Retrospectively registered.

Clinical and Wear Analyses of 9 Large Metal-on-Metal Total Hip Prostheses.

BACKGROUND: Metal-on-Metal (MoM) total hip arthroplasties (THA) are associated with pseudotumor formation and high revision rates. This prospective study analysed the clinical and wear analyses of 9 large Metal-on-Metal (MoM) total hip arthroplasties (THA) to understand the underlying mechanisms of failure. The MoM bearings were revised for multiple reasons; the main reason was pseudotumor formation. MATERIALS AND METHODS: From 2006 till 2010 the Reinier de Graaf Hospital implanted 160 large head M2a-Magnum™ (Biomet Inc. Warsaw, Indiana, USA) THAs in 150 patients. The first year, 9 bearings were revised and analysed at the Biomechanics Section, Hamburg University of Technology, Germany. We performed clinical (Harris Hip Score, radiographic analysis, blood cobalt and chromium) and wear analysis (implant, tissue and fluid) of the 9 bearings. Since this study did not fall under the scope of the Medical Research Involving Human Subjects Act in The Netherlands, no ethical approval was necessary. In this prospective study all patient details were anonymized by the corresponding author, all other authors were blinded during the research and wear analyses. Patients with bilateral MoM implants were excluded. RESULTS: The 9 bearings had a median (IQR) survival of 41.0 (25) months in situ. From these bearings, three showed no noticeable wear. The median (IQR) head wear volume was 3.2 (3.6) mm3 and maximum wear depth 0.02 (0.02) mm. For the cup the median (IQR) wear volume was 0.23 (0.3) mm3 with a maximum wear depth of 0.03 (0.05) mm. CONCLUSION: An early identification of parameters related to failure of the MoM THA, such as pain, decreased range of motion, radiographic changes and high levels of blood cobalt and chromium is of great importance for patient's quality of life. Especially now patients and surgeons face the long term effects of all these bearings still in situ. This study reports the clinical and wear analyses of 9 MoM THA. In the majority of this group the reason for revision was pseudotumor formation. Most bearings showed signs of wear, however with a great diversity in clinical analysis, in inclination angle, serum cobalt and chromium levels as well as wear analysis. For a better understanding of the underlying mechanisms related with failure, more wear analyses of revised MoM bearings are necessary as well as a frequent follow-up of the patients with a MoM bearing.

Model-based roentgen stereophotogrammetric analysis of the surface replacement trapeziometacarpal total joint arthroplasty.

The primary aim of this clinical and radiostereometric study was to study the migration pattern of the surface replacement trapeziometacarpal joint prosthesis (SRTMTMC, Avanta®, San Diego, CA). The secondary aims were to assess patient-related outcomes and prosthesis survival 5 years after surgery. Ten patients received the prosthesis. Radiostereometric radiographs were obtained 6 weeks, 6 months, 1 year and 5 years post-operatively and were analysed using model-based software. All patients completed DASH and Nelson Hospital scores at these follow-ups. Mean translations varied between 0.0 and 0.5 mm after 5 years. Rotation values could be calculated in six patients and mean rotations varied between -0.3 and 2.3°, although the precision of rotation values seems to be poor. The 5-year survival rate was 80%. Mean pre-operative DASH and Nelson Hospital scores were 53 (SD 14) and 51 (SD 13), respectively. Six months post-operatively, the DASH and Nelson Hospital scores had both significantly improved to 25 (SD 20) and 74 (SD 18) and remained high after 5 years. Implant stability was good 5 years post-operatively, and early migration did not predict implant failure in this study. LEVEL OF EVIDENCE: IV.

Feasibility of model-based Roentgen Stereophotogrammetric Analysis to evaluate early migration of the trapeziometacarpal joint prosthesis.

BACKGROUND: The purpose of this study was to determine the feasibility of Roentgen Stereophotogrammetric Analysis (RSA) in total joint arthroplasty of the trapeziometacarpal (TMC) joint of the thumb. METHODS: In five cadaveric hands the TMC-joint was replaced by the Surface Replacement Trapeziometacarpal prosthesis (SR™ TMC prosthesis; Avanta, San Diego, CA) and tantalum beads of 0.8 mm were implanted for RSA. RSA radiographs in two directions were made in ten positions to calculate the measurement error. Migration values from zero are indicative for the measurement error. The number of detected markers was recorded. RESULTS: The accuracy analysis showed that for the translations the mean measurement error varied between 0.003 mm (SD 0.057) and 0.055 mm (SD 0.133). For the rotations values ranged from 0.034° (SD 1.759) to 0.502° (SD 1.617). CONCLUSIONS: RSA analysis of the SR™ TMC prosthesis is feasible. The measurement error is good for the translations but high for the rotations. The latter is due to the close position of the markers relative to each other. Level of evidence III.

No effect of the infiltration of local anaesthetic for total hip arthroplasty using an anterior approach: a randomised placebo controlled trial.

Only limited data are available regarding the infiltration of local anaesthetic for total hip arthroplasty (THA), and no studies were performed for THA using the anterior approach. In this prospective, randomised placebo-controlled study we investigated the effect of both standard and reverse infiltration of local anaesthetic in combination with the anterior approach for THA. The primary endpoint was the mean numeric rating score for pain four hours post-operatively. In addition, we recorded the length of hospital stay, the operating time, the destination of the patient at discharge, the use of pain medication, the occurrence of side effects and pain scores at various times post-operatively. Between November 2012 and January 2014, 75 patients were included in the study. They were randomised into three groups: standard infiltration of local anaesthetic, reversed infiltration of local anaesthetic, and placebo. There was no difference in mean numeric rating score for pain four hours post-operatively (p = 0.87). There were significantly more side effects at one and eight hours post-operatively in the placebo group (p = 0.02; p = 0.03), but this did not influence the mobilisation of the patients. There were no differences in all other outcomes between the groups. We found no clinically relevant effect when the infiltration of local anaesthetic with ropivacaine and epinephrine was used in a multimodal pain protocol for THA using the anterior approach.

Which patient characteristics influence length of hospital stay after primary total hip arthroplasty in a 'fast-track' setting?

After implementation of a 'fast-track' rehabilitation protocol in our hospital, mean length of hospital stay for primary total hip arthroplasty decreased from 4.6 to 2.9 nights for unselected patients. However, despite this reduction there was still a wide range across the patients' hospital duration. The purpose of this study was to identify which specific patient characteristics influence length of stay after successful implementation of a 'fast-track' rehabilitation protocol. A total of 477 patients (317 female and 160 male, mean age 71.0 years; 39.3 to 92.6, mean BMI 27.0 kg/m(2);18.8 to 45.2) who underwent primary total hip arthroplasty between 1 February 2011 and 31 January 2013, were included in this retrospective cohort study. A length of stay greater than the median was considered as an increased duration. Logistic regression analyses were performed to identify potential factors associated with increased durations. Median length of stay was two nights (interquartile range 1), and the mean length of stay 2.9 nights (1 to 75). In all, 266 patients had a length of stay ≤ two nights. Age (odds ratio (OR) 2.46; 95% confidence intervals (CI) 1.72 to 3.51; p < 0.001), living situation (alone vs living together with cohabitants, OR 2.09; 95% CI 1.33 to 3.30; p = 0.002) and approach (anterior approach vs lateral, OR 0.29; 95% CI 0.19 to 0.46; p < 0.001) (posterolateral approach vs lateral, OR 0.24; 95% CI 0.10 to 0.55; p < 0.001) were factors that were significantly associated with increased length of stay in the multivariable logistic regression model.

Severe Wear and Pseudotumor Formation Due to Taper Mismatch in a Total Hip Arthroplasty: A Case Report.

CASE: We describe the case of a seventy-six-year-old woman who had undergone bilateral total hip arthroplasty with Zweymüller-Metasul prostheses in 1996. After a fall sixteen years after the index procedures, radiographs suggested a taper fracture of the left total hip arthroplasty. However, revision surgery showed pseudotumor formation, with no evidence of taper fracture. Analysis of the prosthesis showed massive wear of the male stem taper caused by a mismatch between the stem taper and the head taper. CONCLUSION: This case vividly demonstrates how taper size mismatch can cause dramatic metal wear and increased release of metal ions, resulting in pseudotumor formation.

Combining bisphosphonates with allograft bone for implant fixation.

The aim of this review was to discuss the current state of research of combining bisphosphonates with allograft bone for implant fixation. The allograft bone can only be reached by the bisphosphonate once it has been revascularized. However, this can be circumvented by local administration of bisphosphonates. Several animal studies showed that local application of bisphosphonates might protect the graft from resorption. There seems to be an optimum concentration for local application, however, this optimum varies for all different bisphosphonates. It can be concluded that local administration of bisphosphonates might play an important role in improving stability after surgery in which a prosthesis is combined with allograft bone to restore bony defects, however caution should be taken when extrapolating results of animal research to the human clinical situation. More research is needed to study the effect of local bisphophonate use in humans and to study possible side effects.

Comparison of contamination of femoral heads and pre-processed bone chips during hip revision arthroplasty.

With bone impaction grafting, cancellous bone chips made from allograft femoral heads are impacted in a bone defect, which introduces an additional source of infection. The potential benefit of the use of pre-processed bone chips was investigated by comparing the bacterial contamination of bone chips prepared intraoperatively with the bacterial contamination of pre-processed bone chips at different stages in the surgical procedure. To investigate baseline contamination of the bone grafts, specimens were collected during 88 procedures before actual use or preparation of the bone chips: in 44 procedures intraoperatively prepared chips were used (Group A) and in the other 44 procedures pre-processed bone chips were used (Group B). In 64 of these procedures (32 using locally prepared bone chips and 32 using pre-processed bone chips) specimens were also collected later in the procedure to investigate contamination after use and preparation of the bone chips. In total, 8 procedures had one or more positive specimen(s) (12.5 %). Contamination rates were not significantly different between bone chips prepared at the operating theatre and pre-processed bone chips. In conclusion, there was no difference in bacterial contamination between bone chips prepared from whole femoral heads in the operating room and pre-processed bone chips, and therefore, both types of bone allografts are comparable with respect to risk of infection.