In all, 145 of 160 hips (90%) were considered safe from impingement. Patients with highest risk are those with biological or surgical spinal fusion; patients with dangerous spinal imbalance can be safe with correct acetabular component position. The clinical relevance of the study is that it correlates acetabular component position to spinal pelvic mobility which provides guidelines for total hip arthroplasty. Cite this article: Bone Joint J 2017;99-B(1 Supple A):37-45.

Novel synthetic mimics of antimicrobial peptides have been developed to exhibit structural properties and antimicrobial activity similar to those of natural antimicrobial peptides (AMPs) of the innate immune system. These molecules have a number of potential advantages over conventional antibiotics, including reduced bacterial resistance, cost-effective preparation, and customizable designs. In this study, we investigate a family of nylon-3 polymer-based antimicrobials. By combining vesicle dye leakage, bacterial permeation, and bactericidal assays with small-angle X-ray scattering (SAXS), we find that these polymers are capable of two interdependent mechanisms of action: permeation of bacterial membranes and binding to intracellular targets such as DNA, with the latter necessarily dependent on the former. We systemically examine polymer-induced membrane deformation modes across a range of lipid compositions that mimic both bacteria and mammalian cell membranes. The results show that the polymers' ability to generate negative Gaussian curvature (NGC), a topological requirement for membrane permeation and cellular entry, in model Escherichia coli membranes correlates with their ability to permeate membranes without complete membrane disruption and kill E. coli cells. Our findings suggest that these polymers operate with a concentration dependent mechanism of action: at low concentrations permeation and DNA binding occur without membrane disruption, while at high concentrations complete disruption of the membrane occurs. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins.

Level III-retrospective comparative study.

No abstract

Background: Retrograde percutaneous pinning often involves intra-articular pin placement. Classic teaching has cautioned about the risk of septic arthritis with intra-articular pins, although an incidence has not been reported for this complication. The purpose of this study was to determine the incidence of pin tract infections and septic arthritis following retrograde percutaneous pinning of the distal femur. Methods: A retrospective review identified patients who underwent retrograde percutaneous pinning of the distal femur for osteotomy or physeal fracture fixation at a tertiary pediatric hospital from 2006 to 2017 and had at least 3 months follow-up. The incidence of pin site infections and septic arthritis was determined. Results: In total, 163 patients met criteria, 142 patients with osteotomies and 21 with physeal fractures. The mean pin duration was 33.2±9.0 days (range: 18 to 68 d). Pin duration of ≥30 days was associated with an increased rate of pin tract infections (11.2% vs. 1.4%, P=0.01). The incidence of pin tract infections was 6.7% (11/163), including 9.5% (2/21) in those with fractures and 6.3% (9/142) following osteotomy (P=0.64). There were no cases of septic arthritis. Of the 11 patients with pin tract infections, 9 were treated successfully with oral antibiotics and 2 patients (1.2%) underwent surgical intervention for infection. Treatment of pin infections with oral antibiotics alone was successful in all 7 patients whose pins were removed within 35 days of surgery, but in only 2 of 4 whose pins were removed later (P=0.11). Of the 2 patients who required irrigation and debridement, one had a superficial pin site infection and retained subcutaneous pin and the other had a pin tract abscess and osteomyelitis at the osteotomy site. Conclusions: Of 163 patients who underwent retrograde percutaneous pinning of the distal femur, no patient developed septic arthritis and the incidence of pin site infections was 6.7% (11/163). Intra-articular retrograde percutaneous pinning of the distal femur is a safe technique with a low risk of septic arthritis. Level of Evidence: Level III—case-control study.

No abstract

Background: The purpose of this study is to assess the incidence, risk factors for, and types of respiratory complications occurring in patients undergoing lumbar spine surgery.Methods: Patients undergoing various lumbar spine surgeries from 2007 to 2014 were identified using the PearlDiver patient record database from the nationwide insurance provider Humana Inc. Patient records were analyzed using International Classification of Diseases, Ninth Revision codes and Current Procedural Terminology codes to determine the incidence of pneumonia, pleural effusion, pulmonary collapse, and acute respiratory failure for each procedure type. The incidence of these complications in patients with the risk factors diabetes mellitus, chronic obstructive pulmonary disease (COPD), and smoking was also examined.Results: A total of 64,891 patients (33,280 females; 31,611 males) within the Humana database underwent various lumbar procedures from 2007 to 2014. The overall incidence of respiratory complications in patients undergoing lumbar procedures was 5.7% (n ¼ 3694) within 1 month of having the procedure. Pulmonary collapse was the most common complication with an incidence of 4.3% (n ¼ 2792), followed by pneumonia 1.98% (n ¼ 1285), acute respiratory failure 1.97% (n ¼ 1279), and pleural effusion 1.6% (n ¼ 1048). For each respiratory complication studied, single level discectomy had the lowest complication rate and multilevel anterior lumbar interbody fusion had the highest complication rate. The incidence of each individual respiratory complication was higher in patients who had a history of smoking, COPD, or diabetes mellitus than it was in patients with none of these 3 risk factors (P , .01). Conclusion:The results of this study show that patients who have a history of smoking, COPD, or diabetes mellitus are at a greater risk for respiratory complications following lumbar spine surgery. These findings are useful for patient selection, clinical decision-making, and preoperative counseling.

PurposeClinical presentation of paediatric septic arthritis (SA) can be similar to other joint pathologies. Despite potential for infection in all major joints, most diagnostic criteria are based on values from the hip. This study identifies the best joint aspirate values in diagnosing SA in all joints.MethodsIn all, 166 patients who underwent 172 joint aspirations at the authors’ institution between 01 September 2004 and 01 September 2014 were retrospectively identified. Recorded measures included age, sex, duration of symptoms, fever history, weight-bearing status, aspiration results, serum results and antibiotic administration. Patients were placed in the following four categories: ‘culture confirmed SA’ (C-SA), ‘suspected SA’ (S-SA), ‘Other’ and ‘Other-rheumatologic’ (Other-R), a subcategory of ‘Other’.ResultsMost common sites of aspiration were the knee (55%) and hip (29%). Diagnostic grouping was as follows: C-SA = 44, S-SA = 45, Other = 83 (Other-R = 21). Fever and non-weight-bearing prior to admission were useful predictors of SA, though in C-SA patients, 21% did not have a fever and 23% could weight bear at the time of admission. Aspirate white blood cell (WBC) count was significantly greater in both C-SA (92 000 cells/hpf) and S-SA (54 000) than in Other (10 000) and Other-R (18 000) patients. The percentage of polymorphonuclear (%PMN) was also significantly greater in C-SA (81.1%) and S-SA (80.9%) than in Other (57.9%) and Other-R (63.3%).ConclusionJoint aspirate values, especially %PMN, are valuable in diagnosing SA. Additionally, antibiotics pre-aspiration did not affect %PMN, facilitating subsequent diagnosis of infection. Lastly, while aspirate WBC count was a valuable indicator of SA, this finding is not as definitive as previous research suggests.Level of EvidenceIV Case Series