Biomechanical comparison of ulnar collateral ligament reconstruction with single-tunnel proximal suspensory fixation versus modified docking technique.

Background: Despite technical advancement, elbow ulnar collateral ligament (UCL) reconstruction is a challenging procedure due to the limitations regarding the challenging tunnel placement and potential injury to the ulnar nerve. Furthermore, current techniques for reconstruction and repair are inferior functionally and biomechanically when compared to native UCL tissue. A modified docking technique using a single-tunnel proximal suspensory fixation may reduce complications and potentially provide a technique for UCL reconstruction that is biomechanically superior. Decreasing the number of bone tunnels decreases the number of places that bone tear through could occur. The purpose was to evaluate and compare the biomechanical performances for 2 elbow UCL reconstruction techniques: (1) standard docking technique (SD) and (2) a proximal single tunnel (PST) technique using a suspensory fixation. We hypothesized that the PST technique would be biomechanically superior to the SD technique. Methods: Twelve matched pairs of cadaveric elbows were dissected and fixed at 70 degrees for biomechanical testing. Gracilis grafts were used for a docking reconstruction and the modified reconstruction with a PST suspensory fixation. A cyclic valgus torque protocol was used to precondition specimens for either reconstruction technique and the ulnohumeral gapping was then assessed. Following gapping measurements, postsurgical specimens underwent a valgus rotation applied at a rate of 5°/s until the anterior band of the UCL failed or fracture occurred. Ultimate load to failure, stiffness, and mode of failure were recorded. Results: There were no statistical differences between the two groups. Mean rotational stiffness of the SD (2.3 ± 0.6 Nm/deg) compared to the PST (1.9 ± 0.7 Nm/deg) (P = .41) and mean ultimate failure torque of the SD (30.5 ± 9.2 Nm) compared to the PST (30.9 ± 8.6 Nm) (P = .86) were similar. There was also no statistically significant difference (P = .83) when comparing the native UCL ulnohumeral gapping (6.0 ± 2.0 mm) to the mean ulnohumeral gapping of the SD reconstruction (6.0 ± 1.8 mm). Conclusions: This study compares the biomechanical strength of elbow UCL reconstructions performed using the SP technique to that of a PST technique. Among all tested parameters, including ultimate failure torque, stiffness, and ulnohumeral gapping, there were no statistically significant differences between the 2 techniques.

Thermomechanical Combination Injuries: A Rare But Life-Threatening Entity.

Thermomechanical combination injuries (TMCIs) are feared for their demanding preclinical and clinical management and bear the risk of high mortality compared to the single injury of a severe burn or multiple trauma. There remains a significant lack of standardized algorithms for diagnostics and therapy of this rare entity. The objective of the present study was to profile TMCI aiming at standardized procedures. In this study, TMCIs were extracted from our burn database of a level 1 burn and trauma center. From 2004 to 2017, all patients with TMCI were retrospectively analyzed. Further inclusion criteria were multiple trauma accompanied by burn with ≥10% TBSA. Patient and injury characteristics including injury severity score and outcome parameter were analyzed. A total of 45 patients matched the selective inclusion criteria of TMCI, comprising 4% of all burn injuries during the period. The average age was 38 years (range: 14-86), with a mean TBSA of 43% (range: 10-97%). The mean recorded temperature at admission was 34.8°C (range: 29.6-37.1) with 2215 ml volume of resuscitation fluids (range: 500-8000) administered preclinically in total. The mean injury severity score was 16. The overall mortality rate was 22%. TMCIs are rare and life-threatening events that require highly qualified management in combined level 1 trauma and burn centers to address both burn and trauma treatment. The multiple injury pattern is diverse, complicating standardized management in view of burn care-specific measures, as normothermia and restrictive volume management. The present study reveals further profiles and underlines the need for addressing TMCIs in ABLS®, ATLS®, and PHTLS® programs.

A new animal model for delayed osseous union secondary to osteitis.

BACKGROUND: The treatment of infection-related delayed bone unions is still very challenging for the orthopedic surgeon. The prevalence of such infection-related types of osteitis is high in complex fractures, particularly in open fractures with extensive soft-tissue damage. The aim of this study was to develop a new animal model for delayed union due to osteitis. METHODS: After randomization to infected or non-infected groups 20 Sprague-Dawley rats underwent a transverse fracture of the midshaft tibia. After intramedullary inoculation with staphylococcus aureus (10(3) CFU) fracture stabilization was done by intramedullary titanium K-wires. After 5 weeks all rats were euthanized and underwent biomechanical testing to evaluate bone consolidation or delayed union, respectively. Micro-CT scans were additionally used to quantitatively evaluate the callus formation by the score of Lane and Sandhu. Blood samples were taken to analyze infectious disease markers (day 1, 14 and 35). RESULTS: Biomechanical testing showed a significant higher maximum torque in the non-infected group 5 weeks postoperatively compared with the infected group (p < 0.001). According to the Lane and Sandhu score a significantly higher callus formation was found in the non-infected group (p < 0.001). Similarly, the leucocyte count in the infected group was significantly higher than in the non-infected group (p < 0.05). CONCLUSIONS: Here we have established a new animal model for delayed osseous union secondary to osteitis. The animal model appears to be appropriate for future experimental studies to test new therapeutic strategies in these difficult to treat bone healing complications.

Odor classification: a review of factors influencing perception-based odor arrangements.

Decoding the psychological dimensions of human odor perception has long been a central issue of olfactory research. Odor scientists as well as fragrance professionals have tried to establish comprehensive standards for the description, measurement, and prediction of odor quality characteristics. As odor percepts could not be linked to a few measurable physicochemical features of odorous compounds or physiological characteristics of the olfactory system, odor qualities have often been assessed by perception-based ratings. Although they have been applied for more than 5 decades, these psychological approaches have not yielded a comprehensive or generally accepted classification system yet. We assumed that design and methodology of these studies have largely prevented the development of unbiased odor arrangements. To address this issue, we reviewed 28 perception-based classification studies and found that their outcome has been largely determined by 4 influencing factors: 1) interindividual differences in perceptual and verbal abilities of subjects, 2) stimuli characteristics, 3) approaches of data collection, and 4) methods of data analysis. We discuss the effects of each factor in detail and illustrate how odor systems have reflected perceptual qualities as well as the conditions under which these have been assessed.

Influence of statins locally applied from orthopedic implants on osseous integration.

BACKGROUND: Simvastatin increases the expression of bone morphogenetic protein 2 (BMP-2) in osteoblasts, therefore it is important to investigate the influence of statins on bone formation, fracture healing and implant integration. The aim of the present study was to investigate the effect of simvastatin, locally applied from intramedullary coated and bioactive implants, on bone integration using biomechanical and histomorphometrical analyses. METHODS: Eighty rats received retrograde nailing of the femur with titanium implants: uncoated vs. polymer-only (poly(D,L-lactide)) vs. polymer plus drug coated (either simvastatin low- or high dosed; "SIM low/ high"). Femurs were harvested after 56 days for radiographic and histomorphometric or biomechanical analysis (push-out). RESULTS: Radiographic analysis revealed no pathological findings for animals of the control and SIM low dose group. However, n=2/10 animals of the SIM high group showed osteolysis next to the implant without evidence of bacterial infection determined by microbiological analysis. Biomechanical results showed a significant decrease in fixation strength for SIM high coated implants vs. the control groups (uncoated and PDLLA). Histomorphometry revealed a significantly reduced total as well as direct bone/implant contact for SIM high- implants vs. controls (uncoated and PDLLA-groups). Total contact was reduced for SIM low vs. uncoated controls. Significantly reduced new bone formation was measured around SIM high coated implants vs. both control groups. CONCLUSIONS: This animal study suggests impaired implant integration with local application of simvastatin from intramedullary titanium implants after 8 weeks when compared to uncoated or carrier-only coated controls.