Stress Modulation of Fracture Fixation Implants Beltran, Michael J; Collinge, Cory A; Gardner, Michael J
Journal of the American Academy of Orthopaedic Surgeons,
2016-October, Volume:
24, Issue:
10
Journal Article
Peer reviewed
Stress modulation is the concept of manipulating bridge plate variables to provide a flexible fixation construct that allows callus formation through uneventful secondary bone healing. Obtaining ...absolute stability through the anatomic reduction of all fracture fragments comes at the expense of fracture biology, whereas intramedullary nailing, which is more advantageous for diaphyseal fractures of the lower extremity, is technically demanding and often may not be possible when stabilizing many metaphyseal fractures. Overly stiff plating constructs are associated with asymmetric callus formation, early implant failure, and fracture nonunion. Numerous surgeon-controlled variables can be manipulated to increase flexibility without sacrificing strength, including using longer plates with well-spaced screws, choosing titanium or stainless steel implants, and using locking or nonlocking screws. Axially dynamic emerging concepts, such as far cortical locking and near cortical overdrilling, provide further treatment options when bridge plating techniques are used.
Though nitrogen fixation by epiphytic diazotrophs on pelagic Sargassum has been recognized for decades, it has been assumed to contribute insignificantly to the overall marine nitrogen budget. This ...six-year study reframes this concept through long-term measurements of Sargassum community nitrogen fixation rates, and by extrapolating mass-specific rates to a theoretical square meter portion of Sargassum mat allowing for comparison of these rates to those of other marine and coastal diazotrophs. On 24 occasions from 2015 to 2021, rates of nitrogen fixation were measured using whole fronds of Sargassum collected from the western edge of the Gulf Stream off Cape Hatteras, North Carolina. Across all dates, mass-specific rates ranged from 0 to 37.77 mumol N g.sup.-1 h.sup.-1 with a mean of 4.156 mumol N g.sup.-1 h.sup.-1 . Extrapolating using a mat-specific density of Sargassum, these rates scale to a range of 0 to 30,916 mumol N m.sup.-2 d.sup.-1 and a mean of 3,697 mumol N m.sup.-2 d.sup.-1 . Quantifying this community's rates of nitrogen fixation over several years captured the sometimes-extreme variability in rates, characteristic of marine diazotrophs, which has not been reported in the literature to date. When these measurements are considered alongside estimates of the density of pelagic Sargassum, rates of nitrogen fixation by Sargassum's epiphytic diazotrophs rival that of their coastal macrophyte and planktonic counterparts. Given Sargassum's wide and expanding geographic range, the results of this study suggest this community may contribute reactive nitrogen on a meaningful, basin-wide scale, which merits further study.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background There is no consensus on the best treatment for periprosthetic supracondylar fracture.
Material and methods We systematically summarized and compared results of different fixation ...techniques in the management of acute distal femur fractures above a total knee arthroplasty (TKA). Several databases were searched (Medline, Cochrane library, OTA and AAOS abstract databases) and baseline and outcome parameters were abstracted.
Results We extracted data from 29 case series with a total of 415 fractures. The following outcomes were noted: a nonunion rate of 9%, a fixation failure rate of 4%, an infection rate of 3%, and a revision surgery rate of 13%. Retrograde nailing was associated with relative risk reduction (RRR) of 87% (p = 0.01) for developing a nonunion and 70% (p = 0.03) for requiring revision surgery compared to traditional (non-locking) plating methods. Point estimates also suggested risk reductions for locking plates, although these were not statistically significant (57% for nonunion, p = 0.2; 43% for revision surgery, p = 0.23) compared to traditional plating. RRRs for nonunion and revision surgery were also statistically significantly lower for retrograde nailing and locking plates compared to nonoperative treatment.
Interpretation Modern-day treatment methods are superior to conventional treatment options in the management of distal femur fractures above TKAs. The results should be interpreted with caution, due to the lack of randomized controlled trials and the possible selection bias in case series.
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DOBA, FSPLJ, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Microbial communities play critical roles in fixing carbon from the atmosphere and fixing it in the soils. However, the large‐scale variations and drivers of these microbial communities remain poorly ...understood. Here, we conducted a large‐scale survey across China and found that soil autotrophic organisms are critical for explaining CO2 fluxes from the atmosphere to soils. In particular, we showed that large‐scale variations in CO2 fixation rates are highly correlated to those in autotrophic bacteria and phototrophic protists. Paddy soils, supporting a larger proportion of obligate bacterial and protist autotrophs, display four‐fold of CO2 fixation rates over upland and forest soils. Precipitation and pH, together with key ecological clusters of autotrophic microbes, also played important roles in controlling CO2 fixation. Our work provides a novel quantification on the contribution of terrestrial autotrophic microbes to soil CO2 fixation processes at a large scale, with implications for global carbon regulation under climate change.
This study demonstrated that, on a large scale, soil autotrophic organisms are critical for explaining CO2 fluxes from the atmosphere to soils. Soil CO2 fixation rates are highly correlated to autotrophic bacteria and phototrophic protists. Paddy soils display four‐fold of CO2 fixation rates over upland and forest soils. Precipitation and pH, together with key ecological clusters of autotrophic microbes, also play important roles in controlling CO2 fixation.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Proximal humerus, humeral shaft, and distal humerus fractures are all common adult fractures, and often occur in older patients. While the treatment of proximal humerus fractures remains ...controversial, certain fractures benefit from plate fixation such as fracture-dislocations and head-split fractures. When plate fixation is chosen, anatomic reduction and restoration of the medial calcar are important for successful results. Further research is required to minimize complications and determine the optimal surgical candidates for plate fixation. Humeral shaft fractures are generally treated non-operatively. However, certain shaft fractures warrant plate fixation, such as open fractures, those with associated forearm fractures, and those in poly-trauma patients. Choice of surgical approach and plate depends on the location and type of the fracture. The majority of intra-articular distal humerus fractures should be treated with plate fixation. Dual plating is generally accepted as the gold standard treatment, while the optimal surgical approach and plate configuration requires more research.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Background
The best treatment for intertrochanteric hip fractures is controversial. The use of cephalomedullary nails has increased, whereas use of sliding hip screws has decreased despite the lack ...of evidence that cephalomedullary nails are more effective. As current orthopaedic trainees receive less exposure to sliding hip screws, this may continue to perpetuate the preferential use of cephalomedullary nails, with important implications for resident education, evidence-based best practices, and healthcare cost.
Questions/purposes
We asked: (1) What are the current practice patterns in surgical treatment of intertrochanteric fractures among orthopaedic surgeons? (2) Do surgical practice patterns differ based on surgeon characteristics, practice setting, and other factors? (3) What is the rationale behind these surgical practice patterns? (4) What postoperative approaches do surgeons use for intertrochanteric fractures?
Methods
A web-based survey containing 20 questions was distributed to active members of the American Academy of Orthopaedic Surgeons. Three thousand seven-hundred eighty-six of 10,321 invited surgeons participated in the survey (37%), with a 97% completion rate (3687 of 3784 responded to all questions in the survey). The survey elicited information regarding surgeon demographics, preferred management strategies, and decision-making rationale for intertrochanteric fractures.
Results
Surgeons use cephalomedullary nails most frequently for treatment of intertrochanteric hip fractures. Sixty-eight percent primarily use cephalomedullary nails, whereas only19% primarily use sliding hip screws, and the remaining 13% use cephalomedullary nails and sliding hip screws with equal frequency. The cephalomedullary nail was the dominant approach regardless of experience level or practice setting. Surgeons who practiced in a nonacademic setting (71% versus 58%; p < 0.001), did not supervise residents (71% versus 61%; p < 0.001), or treated more than five intertrochanteric fractures a month (78% versus 67%; p < 0.001) were more likely to use primarily cephalomedullary nails. Of the surgeons who used only cephalomedullary nails, ease of surgical technique (58%) was cited as the primary reason, whereas surgeons who used only sliding hip screws cite familiarity (44%) and improved outcomes (37%) as their primary reasons. Of those who use only short cephalomedullary nails, ease of technique (59%) was most frequently cited. Postoperatively, 67% allow the patient to bear weight as tolerated. Nearly all respondents (99.5%) use postoperative chemical thromboprophylaxis.
Conclusions
Despite that either sliding hip screw or cephalomedullary nail fixation are associated with equivalent outcomes for most intertrochanteric femur fractures, the cephalomedullary nail has emerged as the preferred construct, with the majority of surgeons believing that a cephalomedullary nail is easier to use, associated with improved outcomes, or is biomechanically superior to a sliding hip screw. The difference between what is evidence-based and what is done in clinical practice may be attributed to several factors, including financial considerations, educational experience, or inability of our current outcomes measures to reflect the experiences of surgeons. The educators, researchers, and policymakers among us must work harder to better define the roles of sliding hip screws and cephalomedullary nails and ensure that the increasing population with hip fractures receives high-quality and economically responsible care.
Level of Evidence
Level V, therapeutic study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UL, UM, UPUK, VKSCE, ZAGLJ
Bismuth-rich bismuth oxyhalides (Bi–O–X; X = Cl, Br, I) display high photocatalytic reduction activity due to the promoting conduction band potential. In this work, two Bi5O7I nanosheets with ...different dominant facets were synthesized using either molecular precursor hydrolysis or calcination. Crystal structure characterizations, included X-ray diffraction patterns (XRD), field emission electron microscopy and fast Fourier transformation (FFT) images, showed that hydrolysis and calcination resulted in the dominant exposure of {100} and {001} facets, respectively. Photocatalytic data revealed that Bi5O7I–001 had a higher activity than Bi5O7I–100 for N2 fixation and dye degradation. Photoelectrochemical data revealed that Bi5O7I–001 had higher photoinduced carrier separation efficiency than Bi5O7I–100. The band structure analysis also used to explain the underlying photocatalytic mechanism based on the different conduction band position. This work presents the first report about the facet-dependent photocatalytic performance of bismuth-rich Bi–O–X photocatalysts.
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IJS, KILJ, NUK, PNG, UL, UM
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•CuS/KTN composite was prepared via a two-step hydrothermal method.•Vibration and solar energy were harvested to piezo-/photocatalytic N2 fixation.•CuS/KTN presented much better ...performance in photo-/piezocatalytic N2 fixation than KTN.•The high performance was mainly ascribed to the improved charge separation.
This work synthesized a novel CuS/KTa0.75Nb0.25O3 (KTN) heterojunction composite and firstly applied it in photocatalytic and piezocatalytic reduction of N2 to NH3. XRD, Raman, XPS, SEM, and TEM analyses indicate that CuS nanoparticles closely adhered to the surface of KTN nanorods, which facilitates the migration of electrons between the two semiconductors. Mott-Schottky and valence band XPS analysis shows that KNbO3 shows a higher conduction band than CuS, indicating that CuS mainly acts as electron trappers to capture the photogenerated electrons from KTN. Because of the great enhanced spatial separation of photogenerated charge carriers, the CuS/KTN presents much higher performance than pure KNT, which is further confirmed by 1H NMR analysis of the reaction solution. An interesting finding is that synthesized CuS/KTN not only performs well under light irradiation but also can work in an ultrasonic bath, indicating its great potential in photo/piezocatalytic conversion of N2 to NH3. The optimal 10 %CuS/KTN shows an NH3 production rate of 36.2 μmol L−1 g−1 h−1 under ultrasonic vibration, which reaches 7.4 times that of KTN. The electrons generated by KTN through the piezoelectric effect can be captured by CuS, which endows the electrons a longer life to participate in the reaction, thereby improving the catalytic reaction performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background
Two types of implants used for the surgical fixation of extracapsular hip fractures are cephalocondylic intramedullary nails, which are inserted into the femoral canal proximally to ...distally across the fracture, and extramedullary implants (e.g. the sliding hip screw).
Objectives
To compare cephalocondylic intramedullary nails with extramedullary implants for extracapsular hip fractures in adults.
Search methods
We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (April 2010), The Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 1), MEDLINE (1950 to March 2010), EMBASE (1980 to 2010 Week 13), and other sources.
Selection criteria
All randomised and quasi‐randomised controlled trials comparing cephalocondylic nails with extramedullary implants for extracapsular hip fractures.
Data collection and analysis
Both authors independently assessed trial quality and extracted data. Wherever appropriate, results were pooled.
Main results
We included 43 trials containing predominantly older people with mainly trochanteric fractures.
Twenty‐two trials (3749 participants) compared the Gamma nail with the sliding hip screw (SHS). The Gamma nail was associated with increased risk of operative and later fracture of the femur and increased reoperation rate. There were no major differences between implants in wound infection, mortality or medical complications.
Five trials (623 participants) compared the intramedullary hip screw (IMHS) with the SHS. Fracture fixation complications were more common in the IMHS group. Results for post‐operative complications, mortality and functional outcomes were similar in both groups.
Three trials (394 participants) showed no difference in fracture fixation complications, reoperation, wound infection and length of hospital stay for proximal femoral nail (PFN) versus the SHS.
None of the 10 trials (1491 participants) of other nail versus extramedullary implant comparisons for trochanteric fractures provided sufficient evidence to establish definite differences between the implants under test.
Two trials (65 participants) found intramedullary nails were associated with fewer fracture fixation complications than fixed nail plates for unstable fractures at the level of the lesser trochanter.
Two trials (124 participants) found a tendency to less fracture healing complications with the intramedullary nails compared with fixed nail plates for subtrochanteric fractures.
Authors' conclusions
With its lower complication rate in comparison with intramedullary nails, and absence of functional outcome data to the contrary, the SHS appears superior for trochanteric fractures. Further studies are required to confirm whether more recently developed designs of intramedullary nail avoid the complications of previous nails. Intramedullary nails may have advantages over fixed angle plates for subtrochanteric and some unstable trochanteric fractures, but further studies are required.
Evidence on the most effective and cost-effective management of ankle fractures is sparse but evolving. A recent large RCT in older patients with unstable fractures found that management with ...close-contact-casting was functionally equivalent and more cost-effective than internal fixation. We describe temporal and geographic variation in ankle fracture management and estimate the potential savings if close-contact-casting was used more often in older patients.
Patients admitted to hospital in England between 2007/08 and 2016/17 with an ankle fracture were identified using routine hospital episode statistics. We tested whether the use of internal fixation, and the proportion of internal fixations using intramedullary implants, changed over time. We estimated the potential annual cost savings if patients aged 60+ years were treated with close-contact-casting rather than internal fixation, in line with emerging evidence.
Over the 10-year period, there were 223,465 hospital admissions with a primary ankle fracture diagnosis. The incidence (per 100,000) of internal fixation was fairly consistent over time in younger (33.2 in 2007/08, 30.9 in 2016/17) and older (36.5 in 2007/08, 37.4 in 2016/17) patients. The proportion of internal fixations which used intramedullary implants increased in both age groups (17.0-19.5% < 60 years; 15.2-17.4% 60+ years). In 2016/17, the cost of inpatient hospital care for ankle fractures in England was over £63.1million. If 50% of older patients who had an internal fixation instead had close-contact-casting, we estimate that approximately £1.56million could have been saved.
Despite emerging evidence that non-surgical and surgical management achieve equivalent functional outcomes in older patients, the rate of surgical fixation has remained relatively stable over the decade. The health service could achieve substantial savings if a higher proportion of older patients were treated with close-contact-casting, in line with recent evidence.
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CEKLJ, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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