Biochemical markers in emergency thoracic surgery in penetrating trauma.

BACKGROUND: Violent interpersonal acts account for a large proportion of unnatural deaths in South Africa. A significant proportion of unnatural deaths are due to penetrating thoracic trauma and preventable haemorrhage. Current indications for emergent thoracotomy are unreliable. We propose the use of lactate, shock index (SI) and base deficit (BD) as a triage tool in patients with penetrating thoracic injuries to identify those requiring surgical intervention. METHODS: A review of the trauma registry of the Charlotte Maxeke Johannesburg Academic Hospital (CMJAH) was carried out between March 2011 and March 2016. Four hundred and ninety (490) patients were collected consisting of a non-operative group of 246 patients and an operative group of 244 patients. We compared lactate, SI and BD independently and within panels to ascertain which would best predict the need for operative intervention in these patients. Abnormal was defined as lactate ≥ 4 mmol/l, SI ≥ 0.8 and BD ≤ -4 mmol/l. RESULTS: Of the 490 patients, lactate (p < 0.001), SI (p < 0.001) and BD (p < 0.001) differed significantly between operative and non-operative groups. Statistical significance was lost (p = 0.34) once BD was analysed in combination with lactate and SI. Lactate alone was a strong predictor of the need for intervention (area under the curve (AUC) = 0.814). The strongest predictor was a combined panel of lactate and SI (AUC = 0.8308, p < 0.001). CONCLUSION: Lactate and SI in combination are useful as triage tools, and could assist in decision making, by predicting which patients are more likely to require surgical intervention.

Assessment of antimicrobial mismatches in empirical treatment in early PJI after aseptic revision arthroplasty.

Background: In early periprosthetic joint infection (PJI), 'debridement, antibiotics and implant retention' (DAIR) is a widely accepted form of treatment. Empirical antimicrobial treatment is started while culture results of tissue samples taken during debridement are pending. Objectives: In this retrospective study we assessed the antimicrobial mismatch rate between empirical treatment and the susceptibility of the causative microorganisms of PJI after aseptic revision arthroplasty. We analysed risk factors for antimicrobial mismatches and the impact of mismatches on the outcome of PJI treatment. Results: A total of 119 patients were included in the analysis. In 72% (86/119) of the cases there was an antimicrobial mismatch in empirical treatment. Most of the antimicrobial mismatches were caused by multidrug-resistant (MDR) Staphylococcus spp. (77%, 66/86). In multivariable analysis, polymicrobial PJI was significantly associated with antimicrobial mismatch (OR: 6.89; 95% CI: 2.38-19.53; P < 0.001), and antimicrobial mismatch was significantly associated with reduced success rate of PJI treatment (OR: 0.20; 95% CI: 0.05 ±â€…0.82; P = 0.026). There was no difference in successful outcome between PJI caused by Gram-negative bacilli (61%) and Gram-positive bacteria (69%, P = 0.516). Conclusions: Mismatching empirical antimicrobial treatment after DAIR following aseptic revision arthroplasty was significantly associated with failure of PJI treatment. Polymicrobial PJI is a risk factor for antimicrobial mismatch of the empirical treatment of PJI. Antimicrobial mismatch and delay in targeted treatment should be integrated in the approach to optimize antibiotic treatment to improve clinical outcomes, while minimizing unintended side effects of antimicrobial use (antimicrobial stewardship).

The unsuspected prosthetic joint infection : incidence and consequences of positive intra-operative cultures in presumed aseptic knee and hip revisions.

AIMS: Positive cultures are not uncommon in cases of revision total knee and hip arthroplasty (TKA and THA) for presumed aseptic causes. The purpose of this study was to assess the incidence of positive intra-operative cultures in presumed aseptic revision of TKA and THA, and to determine whether the presence of intra-operative positive cultures results in inferior survival in such cases. PATIENTS AND METHODS: A retrospective cohort study was assembled with 679 patients undergoing revision knee (340 cases) or hip arthroplasty (339 cases) for presumed aseptic causes. For all patients three or more separate intra-operative cultures were obtained. Patients were diagnosed with a previously unsuspected prosthetic joint infection (PJI) if two or more cultures were positive with the same organism. Records were reviewed for demographic details, pre-operative laboratory results and culture results. The primary outcome measure was infection-free implant survival at two years. RESULTS: The incidence of unsuspected PJI was 27 out of 340 (7.9%) in TKA and 41 out of 339 (12.1%) in THA. Following revision TKA, the rate of infection-free implant survival in patients with an unsuspected PJI was 88% (95% confidence intervals (CI) 60 to 97) at two years compared with 98% (95% CI 94 to 99) in patients without PJI (p = 0.001). After THA, the rate of survival was similar in those with unsuspected PJI (92% (95% CI 73 to 98) at two years) and those without (94% (95% CI 89 to 97), p = 0.31). CONCLUSION: Following revision of TKA and THA for aseptic diagnoses, around 10% of cases were found to have positive cultures. In the knee, such cases had inferior infection-free survival at two years compared with those with negative cultures; there was no difference between the groups following THA. Cite this article: Bone Joint J 2017;99-B:1482-9.

Optimal pitching axis location of flapping wings for efficient hovering flight.

Flapping wings can pitch passively about their pitching axes due to their flexibility, inertia, and aerodynamic loads. A shift in the pitching axis location can dynamically alter the aerodynamic loads, which in turn changes the passive pitching motion and the flight efficiency. Therefore, it is of great interest to investigate the optimal pitching axis for flapping wings to maximize the power efficiency during hovering flight. In this study, flapping wings are modeled as rigid plates with non-uniform mass distribution. The wing flexibility is represented by a linearly torsional spring at the wing root. A predictive quasi-steady aerodynamic model is used to evaluate the lift generated by such wings. Two extreme power consumption scenarios are modeled for hovering flight, i.e. the power consumed by a drive system with and without the capacity of kinetic energy recovery. For wings with different shapes, the optimal pitching axis location is found such that the cycle-averaged power consumption during hovering flight is minimized. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to traditional wings used by most of flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. With the optimized pitching axis, flapping wings show higher pitching amplitudes and start the pitching reversals in advance of the sweeping reversals. These phenomena lead to higher lift-to-drag ratios and, thus, explain the lower power consumption. In addition, the optimized pitching axis provides the drive system higher potential to recycle energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when using kinetic energy recovery drive systems.

Moderate clinical improvement after revision arthroplasty of the severely stiff knee.

PURPOSE: Revision of the severe stiff total knee arthroplasty (TKA) is challenging, and clinical outcome is inferior to other indications for revision. The purpose of the present study was to determine clinical outcome of TKA revision in patients with severe stiffness (range of motion (ROM) ≤ 70°) and evaluate a possible influence of accompanying findings, such as component malposition, aseptic loosening or instability. METHODS: A prospective cohort of 40 patients with a preoperative ROM ≤ 70° and a minimum of 2-year follow-up after total system revision (Genesis or Legion stemmed condylar implant) was evaluated. ROM, Knee Society Scoring System (KSS) and visual analogue scale (VAS) pain scores were obtained preoperatively and at 2 years. Patient satisfaction and complication rate were assessed. Component malposition was most frequently reported as accompanying finding (n = 27). Comparisons between pre- and postoperative outcome (p < 0.05) and between different subgroups (component malposition, aseptic loosening, and instability) based on accompanying findings were made (no statistical comparison). RESULTS: ROM, KSS and VAS pain scores improved significantly (p < 0.001): median ROM at two years 85° (range 10-125) and median gain 25° (range -10 to +85). Median VAS satisfaction was 53.5 points (range 15-98). Seventeen patients reported at least one complication, including one re-revision. Six patients underwent manipulation under anaesthesia, and five were referred to the pain clinic. No clear differences between subgroups were observed. CONCLUSIONS: TKA revision in patients with severe stiffness resulted in a moderate but significant improved clinical outcome after 2 years. Accompanying abnormalities such as component malposition, aseptic loosening or instability did not influence clinical outcome. Realistic patient counselling on the moderate outcome and possible remaining limitations in daily life might help to improve patient satisfaction. LEVEL OF EVIDENCE: Therapeutic studies-case series with no comparison group, Level IV.

Debridement, antibiotics and implant retention in early periprosthetic joint infection after primary total hip arthroplasty : 88 percent survival after two years follow-up.

Treatment protocols and results of debridement, antibiotics, irrigation and retention of the prosthesis (DAIR) for early prosthetic joint infection (PJI) vary in literature. The purpose of this study was to analyze the results of DAIR with a multidisciplinary designed customized antibiotic protocol for early PJI after primary total hip replacement (THR). We retrospectively analyzed all patients with an early PJI between 2008 and 2012. When an infection was suspected, debridement of the prosthesis, and -collection of intraoperative cultures, was performed. -Patients were multidisciplinary discussed and treated with an appropriate antibiotic scheme for 12 weeks. Primary outcome was retention of the prosthesis after at least two years follow-up and without any signs of infection. We indentified 25 patients with early PJI. At a median follow-up time of 3.1 years (range 2.1-5.5 years), 88% had retention of the prosthesis and no signs of infection. This study suggests that DAIR with a multidisciplinary approach and an aimed antibiotic treatment for early PJI after THR is a reasonable treatment -option with 88% implant retention after two years follow-up.

Dual mobility acetabular component in revision total hip arthroplasty for persistent dislocation: no dislocations in 50 hips after 1-5 years.

BACKGROUND: A dual mobility cup has the theoretic potential to improve stability in primary total hip arthroplasty (THA) and mid-term cohort results are favorable. We hypothesized that use of a new-generation dual mobility cup in revision arthroplasty prevents dislocation in patients with a history of recurrent dislocation of the THA. MATERIALS AND METHODS: We performed a retrospective cohort study of patients receiving an isolated acetabular revision with a dual mobility cup for recurrent dislocation of the prosthesis with a minimum follow-up of 1 year. Kaplan-Meier survival analyses were performed with dislocation as a primary endpoint and re-revision for any reason as a secondary endpoint. RESULTS: Forty-nine consecutive patients (50 hips) were included; none of the patients was lost to follow-up. The median follow-up was 29 months (range 12-66 months). Two patients died from unrelated causes. Survival after 56 months was 100 % based on dislocation and 93 % (95 % CI 79-98 %) based on re-revision for any reason. Radiologic analysis revealed no osteolysis or radiolucent lines around the acetabular component during the follow-up period. CONCLUSION: The dual mobility cup is an efficient solution for instability of THA with a favorable implant survival at 56 months. LEVEL OF EVIDENCE: Level 4, retrospective case series.

Arthrodesis of the knee following failed arthroplasty.

PURPOSE: Primary stability in arthrodesis of the knee can be achieved by external fixation, intramedullary nailing or plate fixation. Each method has different features and results. We present a practical algorithm for arthrodesis of the knee following a failed (infected) arthroplasty, based on our own results and a literature review. METHODS: Between 2004 and 2010, patients were included with an indication for arthrodesis after failed (revision) arthroplasty of the knee. Patients were analyzed with respect to indication, fusion method and bone contact. End-point was solid fusion. RESULTS: Twenty-six arthrodeses were performed. Eighteen patients were treated because of an infected arthroplasty. In total, ten external fixators, ten intramedullary nails and six plate fixations were applied; solid fusion was achieved in 3/10, 8/10 and 3/6, respectively. CONCLUSIONS: There is no definite answer as to which method is superior in performing an arthrodesis of the knee. Intramedullary nailing achieved the best fusion rates, but was used most in cases without--or cured--infection. Our data and the contemporary literature suggest that external fixation can be abandoned as standard fusion method, but can be of use following persisting infection. The Ilizarov circular external fixator, however, seems to render high fusion rates. Good patient selection and appropriate individual treatment are the key to a successful arthrodesis. Based upon these findings, a practical algorithm was developed.

Low central venous oxygen saturation in haemodynamically stabilized trauma patients is associated with poor outcome.

BACKGROUND: Central venous oxygen saturation (ScvO(2)) is suggested to reflect the adequacy of oxygen delivery, and the main objective of the present study was to determine whether ScvO(2) is associated with outcome in haemodynamically stabilized trauma patients. METHODS: Haemodynamically unstable trauma patients receiving a central venous line within 1 h of admission were eligible for inclusion in this prospective observational study. The mean arterial pressure (MAP), lactate and ScvO(2) were recorded at inclusion and every 6 h for 36 h or until lactate was <2.0 mmol/l and ScvO(2) was >75% in two consecutive measurements. Patients with a MAP of ≥70 mmHg were considered to be haemodynamically stabilized. The outcome measure was complications defined as infections, delta sequential organ failure assessment score of >0, and mortality. RESULTS: Fifty patients with a median new injury severity score of 27 (17-34) were analysed. Complications occurred in 33 patients. An association between ScvO(2) following resuscitation to MAP ≥70 mmHg and complications was detected with an odds ratio of 0.94 (95% confidence interval; 0.89-0.99). This association was also significant when adjusted for injury severity. The result implies that a low ScvO(2) value is associated with more complications. The optimal cut-off for ScvO(2) to discriminate between patients who did or did not develop complications was found to be 66.5% (56-86%). CONCLUSIONS: These data suggest that low ScvO(2) in haemodynamically stabilized patients is associated with a poor outcome and that ScvO(2) represents a potential endpoint of resuscitation in trauma patients.

In vivo wear reduction of argon compared to air sterilized UHMW-polyethylene liners.

INTRODUCTION: To date, no studies have been published that report on the in vivo advantages of sterilisation in argon (ARGON) versus air (AIR) of UHMWPE liners with respect to wear extend and pattern in uncemented total hip arthroplasty. METHOD: Femoral penetration rates were measured in 93 AIR and 79 ARGON liners, during a mean follow-up of 8 (3-12) years. RESULTS: During the first 3 years after implantation, both groups showed no differences in mean wear rate (P = 0.13). Thereafter, the ARGON liner demonstrated a decrease in wear rate of 0.04 mm/year from 4 to 6 years (P = 0.006), 0.14 mm/year from 7 to 9 years (P < 0.001), and 0.33 mm/year beyond 9 years follow-up (P = 0.015) compared to the AIR liner. One AIR acetabular component required revision.

Porous-coated femoral components with or without hydroxyapatite in primary uncemented total hip arthroplasty: a systematic review of randomized controlled trials.

The purpose of this systematic review was to determine the clinical and radiologic benefit of hydroxyapatite coating in uncemented primary total hip arthroplasty. A database of Medline articles published up to September 2007 was compiled and screened. Eight studies involving 857 patients were included in the review. Pooled analysis for Harris hip score as a clinical outcome measure demonstrated no advantage of the hydroxyapatite coating (WMD: 1.49, P = 0.44). Radiologically, both groups showed equal presence of endosteal bone ingrowth (RR: 1.04, P = 0.66) and radioactive lines (RR: 1.02, P = 0.74) in the surface area of the prosthesis. This meta-analysis demonstrates neither clinical nor radiologic benefits on the application of a hydroxyapatite coating on a femoral component in uncemented primary total hip arthroplasty.

Trauma and emergency surgery: South African model.

South Africa is a low- to middle-income country with huge disparities in income, and a legacy of a disadvantaged majority. During the last 30 years, many of the advantaged minority found greener pastures and emigrated to first-world countries. We are left with a desperate shortage of specialists (including surgeons), particularly in the public sector. The need is especially acute in secondary and rural hospitals. A career in general surgery has become less attractive because of issues of lifestyle, remuneration, and the expanding requirements of the first-world part of our population.Worldwide, South African surgeons are recognized as hardworking and capable, with a broad repertoire-because that is the way they are trained. They are backed by a relatively small group of subspecialists, and all categories of specialists are burdened by a heavy workload. Continuing surgical education is mandatory but poorly enforced.Trauma surgery and intensive care form a substantial proportion of postgraduate training and general surgical practice. In isolation, these fields cannot sustain the needs and demands for the operative skills of a general surgeon. Trauma surgeons would have to find operative general surgical work to maintain their operative skills (and credibility).Because of the large gaps in service delivery to our population, and the shortage of general surgeons, particularly in secondary centers, there is at present limited space for a discipline of emergency surgery. The primary need for our population is access to well-trained generalists, backed by a small cadre of subspecialists.

Effect of penetrating trunk trauma on the recovery of adult survivors: a pilot study.

Gunshot and/or stab wounds to the trunk are injuries seen in South African hospitals. Patients are managed in the intensive care unit. Prolonged mechanical ventilation with immobilization results in some degree of muscle dysfunction. Our goal was to determine if patients recover adequately spontaneously following critical illness. No formal rehabilitation programmes exist in South Africa for these patients following discharge. A prospective, observational study was conducted. Patients were recruited from three ICUs in Johannesburg. Lung function tests, dynamometry, quality of life, 6-minute-walk, and oxygen uptake tests were performed over 6 months following discharge from the hospital. The control group consisted of existing data for healthy volunteers. Distance walked during 6-minute-walk test was significantly reduced for the study group compared to the control group (1 month [p = 0.00251]; 6 months [p = 0.0355]). At 1 month there was a significant reduction in quadriceps and triceps strength for the study group compared to the control group (p = 0.0089; p = 0.0246, respectively). Quadriceps strength remained significantly reduced for the study group (3 months [p = 0.0489]). No difference in muscle strength was detected between the groups at 6 months. Actual and predicted residual volumes differed significantly for the study group (1 month [p = 0.0034]; 6 months [p = 0.0157]). A trend of muscle weakness (to 3 months), poor exercise capacity, and abnormal lung volumes was identified. A formal rehabilitation programme may be needed to address these disabilities.

[How many steps does a doctor take in the hospital? No difference between internists and general surgeons, but a relationship with age and BMI]. / Hoeveel stappen zet een dokter in het ziekenhuis? Geen verschil tussen internisten en algemeen chirurgen, maar wel samenhang met leeftijd en BMI.

OBJECTIVE: To determine the number of steps taken during working days in the hospital by both internists and general surgeons and whether there is a difference between housemen, registrars and members of the staff. DESIGN: Comparative analysis. METHOD: A validated pedometer was used to count the number of steps taken by housemen, registrars and staff members in the departments of internal medicine and general surgery. The 2 groups of doctors comprised 131 subjects from 13 training hospitals. Possible factors likely to affect the number of steps, such as age, sex, weight and height, were recorded. RESULTS: The average number of steps taken per day was 5325 (range: 1105-10,250) and the average number per hour was 548 (range: 143-1105), with an average working day of 9.8 hours and 8.4 measured days. When corrected for age, sex and hierarchic status, no significant difference was observed between surgeons and internists (p = 0.097). There were also no differences within the hierarchic structure after correction (p = 0.936). Age and BMI seemed to be the most important factors predicting the number of steps in this population. Each additional year of age corresponded with an average decrease of 5 steps per hour on the job (p = 0.001), while each point rise in BMI (+1 kg/m) coincided with an average decrease of 20 steps per hour (p = 0.001). CONCLUSION: After correcting for confounding factors, no differences were observed in the number of steps taken in the hospital by general surgeons and internists. There was also no difference between hierarchic levels. Age and BMI were the most important variables that predicted the number of steps taken per hour in this research population.

Mid-term wear characteristics of an uncemented acetabular component.

We investigated the rate of polyethylene wear of a cementless acetabular component at different periods of follow-up in order to test the hypothesis than an irrecoverable deformation process (creep) was followed by an initially low, but gradually increasing wear rate. We studied prospectively 93 uncemented total hip arthroplasties in 83 patients (mean age 50 years (22 to 63)) with a mean follow-up of 8.2 years (3 to 12). We measured the penetration of the femoral head from radiographs taken immediately after surgery at three, six and nine years, or at the latest follow-up. The median wear rate was 0.17 mm per year in the first three years, a finding which we considered to be caused by creep. Thereafter, the rate of wear declined to 0.07 mm per year (four- to six-year period) and then increased to 0.17 mm per year (seven to nine years) and 0.27 mm per year (more than nine years), which we considered to be a reflection of genuine polyethylene wear. After the nine-year follow-up the wear rates were higher in patients with marked osteolysis. We found no relationship between the inclination angle of the acetabular component or femoral head orientation and the rate of wear. No acetabular component required revision.

Trauma care systems in South Africa.

AIM: To provide an overview of the provision of trauma care in South Africa, a middle income country emerging into a democratic state. METHODS: Literature review. CONCLUSIONS: South Africa is gripped by an almost hidden epidemic of intentional and non-intentional injury, largely driven by alcohol and substance abuse, against a background of poverty and rapid urbanisation. Gross inequities exist in the provision of trauma care. Access to pre-hospital care and overloading of tertiary facilities are the major inefficiencies to be addressed. The burden of disease due to trauma presents unique opportunities for reconstruction and clinical research.

Evolving concepts in the management of colonic injury.

PURPOSE: The management of colonic injury has changed in recent years. This study sought to evaluate current surgical management of injuries to the colon in a busy urban trauma centre, in the light of our increasing confidence in primary repair and evolving understanding of the concepts and practice of damage control surgery. METHODS: A retrospective analysis was made of consecutive patients presenting with colonic injury from January 1 to December 31 1998. Patients without full-thickness lesions of the colon were excluded, as were patients who died within 24 h of admission. Demographic data, wounding patterns and clinical course were studied. RESULTS: One hundred twenty-seven patients were analyzed. Management without colostomy was achieved in 84% of cases. Patients who underwent diversion of the faecal stream had increased morbidity and hospital stay compared to equivalent patients who were repaired primarily. The important subgroup of patients who underwent damage control or abbreviated laparotomy is discussed. CONCLUSION: This study further strengthens the validity of direct repair or resection and primary anastomosis for colonic injury. Strategies to deal with the subgroup of patients at very high risk of postoperative complications are suggested.

Transmediastinal gunshot injuries.

BACKGROUND: Transmediastinal gunshot injuries are a rarely reported injury. Until recently, assessment of the thoracic aorta by angiography preceded the investigation of the esophagus. This order has been recently debated. METHODS: There were 118 patients with potential transmediastinal injuries included in this retrospective study. Unstable patients who were unresponsive to resuscitation were taken to the operating room without previous investigation. Stable patients were routinely investigated initially for injury of the aorta and then for injury of the esophagus. RESULTS: There were 51 patients who underwent urgent thoracotomy/sternotomy. In 27, the hemorrhage was of mediastinal origin; 17 of these patients died of intraoperative bleeding. Eight of the patients had aortic injury, and only one of this group survived. There were 57 stable patients who were investigated initially for injury of the aorta by angiography. It was positive in only one patient who underwent an operation with good results. An investigation of the esophagus followed and revealed esophageal injury in 17 patients. All of them were treated operatively, 15 of them with satisfactory outcome. CONCLUSIONS: Angiography should at present precede esophageal investigations. There is a need for shortening the time between admission and operation. Other modalities that could expedite the investigation of the thoracic aorta and the esophagus should be prospectively evaluated in multi-center studies.