Significant Difference In Survivorship Research Articles

The Fate of Unresurfaced Patellae in Contemporary Total Knee Arthroplasty: Early to Midterm Results

BackgroundLeaving the patella unresurfaced in total knee arthroplasty (TKA) has increased significantly over the past decade in the United States, likely due to modern patella-friendly implants, complications with resurfacing, and the knowledge that historical studies were scientifically confounded. This study evaluated revision-free survivorship out to 8.5 years in a cohort of contemporary primary TKAs with patella-friendly femoral components and unresurfaced patellae. MethodsA total of 1,053 consecutive primary TKAs with unresurfaced patellae were retrospectively reviewed. A selective patellar nonresurfacing protocol was used for all cases. Kaplan-Meier survivorship estimates were calculated based on patellar revision and the latest follow-up. An aggressive lateral patellar facetectomy was performed in 78% (823 of 1,053) of cases. The cohort was 62% women and 43% American Society of Anesthesiologists physical status classification I or II with a mean age and body mass index of 65 years (range, 35 to 94) and 35 kg/m2 (range, 18 to 65), respectively. ResultsA total of 4 (0.4%, 4 of 1,053) unresurfaced patellae were revised. Three were resurfaced as part of other procedures: 2 for global instability and one for aseptic loosening at a mean of 1.6 years; and one patella was resurfaced by an outside surgeon for unexplained pain. The all-cause revision-free survivorship estimate specifically related to the patella was 98.9% (95% confidence interval, 98 to 100) out to 8.5 years. No significant difference in survivorship was related to patellae with or without a lateral patellar facetectomy (99.5 versus 98.1%, P ≥ .191); however, 3 of 4 patellar revisions occurred in TKAs without a lateral patellar facetectomy (P = .035). ConclusionsThe results of this study demonstrate excellent revision-free survivorship related to unresurfaced patellae, particularly when a lateral facetectomy was performed. These early to midterm results using modern patella-friendly femoral components are promising and comparable to resurfaced patellae in the literature. Level of EvidenceIV.

Outcome and Risk Factors Associated with Failures of Isolated Bearing Exchange for Osteolysis in Well-Fixed Cementless Total Hip Arthroplasty

BackgroundIt is often challenging to decide whether to revise only the bearing or femoral acetabular component in the setting of progressive osteolysis without component loosening in revision total hip arthroplasty (THA). In this study, we aimed to (1) compare the survivorship of isolated bearing exchange and single/both component revision for patients with periprosthetic osteolysis without component loosening, and (2) identify potential risk factors associated with failures of isolated bearing exchange. MethodsA total of 228 consecutive cases of revision THA for progressive osteolysis without component loosening was evaluated in 2 groups: (1) 124 component revision and (2) 104 isolated bearing exchange. The primary outcome was survival, with failure defined as repeat revision or reoperation for any reason. Patient risk factors, such as demographics and medical comorbidities, were also analyzed. ResultsThere was no significant difference in survivorship between the component revision group and the bearing exchange group at 10 years (85% vs 82%; P = .89). There was no progression of osteolysis on radiographs at last follow-up for patients with isolated bearing change. Univariate regression modeling demonstrated that renal disease was associated with failure of isolated bearing exchange after revision THA. ConclusionThis study demonstrated that isolated bearing exchange is associated with similar outcomes compared with component revision for aseptic osteolysis without loosening, demonstrating that isolated bearing exchange is a viable option for selected patients with osteolysis in the setting of well-fixed THA components. This provides clinically useful information for surgeons in the surgical treatment of THA patients with wear and osteolysis without component loosening.

Development and Fecundity of Orius minutus (Hemiptera: Anthocoridae) and O. laevigatus Reared on Tetranychus urticae (Acari: Tetranychidae).

The polyphagous predator Orius species is a dominant predator of thrips, mites, and aphids. Orius laevigatus (Fieber) is a well-known commercialized and effective biological control agent, whereas Orius minutus (L.) distributed widely over the world has not been commercialized. To assess potentials of developing O. minutus as a commercial biological control agent, we compared the biological parameters of O. minutus with O. laevigatus when reared on mixed stages of Tetranychus urticae Koch at 27.5°C. Nymphal development of O. laevigatus was shorter (11.30 d) than that of O. minutus (12.25 d), but there was no significant difference in survivorship between the two species. Also, no significant difference was found in either the preoviposition or oviposition periods, lifetime fecundity, or longevity between the two species. However, O. minutus eggs had a higher hatch rate (0.77) than O. laevigatus (0.71). In life table analysis, no difference was found in any parameters, i.e., R0, rm, λ, T, and DT, between O. laevigatus and O. minutus in two-tailed t-tests. In a predation bioassay, O. minutus consumed 1.39 times more adult T. urticae in 24 h than did O. laevigatus, although the predation rate on T. urticae eggs was similar between the two species. These results suggest that O. minutus native to Korea could be developed as a biological control agent against T. urticae.

Ecotypic divergences of the alpine herb Potentilla matsumurae adapted to fellfield-snowbed habitats across a series of mountain sky islands.

Divergent selection due to environmental heterogeneity can lead to local adaptation. However, the ecological and evolutionary processes of local adaptation that occurs across multiple regions are often unknown. Our previous studies reported on the ecotypic divergence within a local area of variation of Potentilla matsumurae, an alpine herb adapted to the fellfield-snowbed environment. Here we investigated large-scale geographic patterns of ecotypic differentiation in this species to infer local adaptation and selective forces across multiple regions. We compiled information on the overall distributions of fellfield and snowbed habitats on the mountains in Japan across the distribution of the species. Next, we conducted common garden experiments to test the adaptive divergence of the fellfield-snowbed plants derived from multiple regions. Finally, we evaluated phylogeographic structures based on cpDNA and allozyme variations and inferred the evolutionary history of ecotype differentiation. The mosaic distribution of the fellfield-snowbed ecotypes across isolated mountaintops constitutes indirect evidence for habitat-specific natural selection. The significant difference in survivorship between the ecotypes observed in a controlled snow environment provides more substantial evidence of local selection. Phylogeographic structures support the hypothesis that ecotypic divergence events from fellfield to snowbed populations occurred independently in at least two distinct regions. Ecotypic divergence of P. matsumurae has occurred across a series of mountain sky islands. Local selection in snowy environments is a driving force that maintains the divergent ecotypes across multiple mountain regions and can contribute to the diversification of plants in heavy-snow regions.

Total Ankle Arthroplasty vs Ankle Arthrodesis

Category: Ankle, Ankle Arthritis Introduction/Purpose: Ankle arthritis is a debilitating disorder which significantly limits activities of daily living and can lead to reduced quality of life. Total ankle arthroplasty(TAA) and ankle arthrodesis are common treatments for ankle arthritis; however, patient indications may differ based on individual patient needs. Few studies compare proportional hazard modeling, survivorship and patient-centered outcomes following these two procedures, which may be useful in determining the appropriate procedure for end-stage ankle arthritis in different patient populations. The purpose of this study was to determine proportional hazards for the risk of failure in patients who underwent TAA vs. arthrodesis, as well as survivorship and outcomes. Methods: All patients >18 years, between January 2009 and November 2013, who underwent TAA or ankle arthrodesis by a single surgeon for treatment of ankle arthritis were included. Patients completed a subjective questionnaire at minimum 2-years following index surgery. Outcomes measures included Foot and Ankle Ability Measure(FAAM), Foot and Ankle Disability Index(FADI), Lysholm, WOMAC, SF-12 physical component summary(PCS) and mental component summary(MCS), Tegner activity scale and patient satisfaction with outcome. Detailed surgical data/intraoperative findings were documented at time of surgery. All data were collected prospectively. Cox proportional hazard modeling and survivorship analysis were performed to assess differences between the two cohorts. Survivorship utilizing Kaplan-Meier method, using a log-rank test, was used to compare median survivorship. Cox-proportional hazard model was conducted to compare hazard rates of surgical failure for patients in each cohort, while adjusting for age at surgery, body mass index(BMI) and sex. All outcome measures were compared between cohorts. Results: There were 97 patients available for analysis. Eight patients failed surgery(9.2%). Demographic data were documented (Table 1). There was no significant difference in failures (TAA=2 failures (6.5%) vs. arthrodesis=6 failures (11.8%)(p=0.709). There was no significant difference in survivorship of surgery between the arthrodesis cohort and the TAA cohort(p=0.785)(Table 1, Figure 1). There was a decrease in survivorship at 4 years in TAA cohort compared to arthrodesis cohort, which was not significant. The hazard ratio was 0.804 [95%CI: 0.111–5.842], indicating that cohort did not have a significant effect on the hazard of surgical failure(p=0.829). Sex, age and BMI did not have a significant effect on the hazard of surgical failure(p>0.05). There was no significant difference in any outcome measures between cohorts(Table 1). Conclusion: There was no significant difference in survivorship or in the hazard of surgical failure based on cohort (TAA and arthrodesis) while accounting for sex, age at surgery and BMI. There was no significant difference in the hazard of surgical failure for factors including age at surgery, BMI or sex. There was no significant difference in survivorship or outcomes between cohorts. Total ankle arthroplasty seems to provide similar results as arthrodesis; however, there was a decrease in survivorship at 4 years in the TAA cohort. Although not significant, this may indicate that survivorship differs during the longer-term follow-up period.

Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the Management of Cancer of the Colon, Rectum and Anus (2017) - Follow Up, Lifestyle and Survivorship.

Association of Coloproctology of Great Britain & Ireland (ACPGBI): Guidelines for the Management of Cancer of the Colon, Rectum and Anus (2017) - Follow Up, Lifestyle and Survivorship.

Oyster Density and Demographic Rates on Natural Intertidal Reefs and Hardened Shoreline Structures

The ubiquitous loss of natural intertidal oyster reefs and associated ecosystem services has fueled restoration efforts throughout the world. Effective restoration requires an understanding of the distribution, density, and demographic rates (growth and survival) of oysters inhabiting existing natural reefs and how these may vary as a function of landscape-scale factors, such as tidal range and fetch distances. Furthermore, natural intertidal habitats are increasingly being replaced with hardened shoreline structures that may be colonized by oysters, yet little is known about habitat quality (as indexed by oyster density and demographic rates) of these hardened structures relative to natural habitats. The present study sought to compare oyster density, demographic rates, and population estimates (1) across estuarine landscape settings to inform natural intertidal oyster reef restoration (i.e., comparing natural intertidal reefs within adjacent water bodies that vary in tidal regimes and fetch distances) and (2) across natural habitats and human-made structures to assess variation in habitat quality between natural reefs and hardened shorelines. Oyster density, growth rates, and population estimates on natural intertidal reefs were greatest within the smaller, more tidally influenced Core Sound versus the larger, wind-driven Pamlico Sound, with no significant difference in survivorship identified between the two water bodies. Natural intertidal reefs and hardened shoreline structures were compared within Pamlico Sound only, with natural intertidal reefs hosting three to eight times higher oyster densities than hardened shoreline structures. When mean oyster density/m2 was multiplied by reef area to estimate population size, natural intertidal reefs within Pamlico Sound hosted considerably greater populations of oysters relative to hardened shorelines. The present study fills an existing need to understand oyster density and demographic rates on natural intertidal reefs and hardened shorelines to better inform future restoration and shoreline management scenarios.

Coronal alignment in total knee replacement: historical review, contemporary analysis, and future direction.

Substantial healthcare resources have been devoted to computer navigation and patient-specific instrumentation systems that improve the reproducibility with which neutral mechanical alignment can be achieved following total knee replacement (TKR). This choice of alignment is based on the long-held tenet that the alignment of the limb post-operatively should be within 3° of a neutral mechanical axis. Several recent studies have demonstrated no significant difference in survivorship when comparing well aligned versus malaligned TKRs. Our aim was to review the anatomical alignment of the knee, the historical and contemporary data on a neutral mechanical axis in TKR, and the feasibility of kinematically-aligned TKRs. Review of the literature suggests that a neutral mechanical axis remains the optimal guide to alignment.

Post-settlement survivorship in two Caribbean broadcasting corals

The post-settlement phase of broadcast-spawned coral life histories is poorly known due to its almost complete undetectability and, hence, presumed low abundance in the field. We used lab-cultured settled polyps of two important Caribbean reef-building species with negligible larval recruitment to quantify early post-settlement survivorship (6–9 weeks) over multiple years/cohorts and differing orientation on a reef in the Florida Keys. Orbicella faveolata showed significantly and consistently better survivorship in vertical rather than horizontal orientation, but no discernable growth overall. Meanwhile, Acropora palmata showed no significant difference in survivorship between orientations, but significantly greater growth in the horizontal orientation. Both species showed significant variation in mean survivorship between cohorts of different years; 0–47 % for O. faveolata and 12–49 % for A. palmata over the observed duration. These results demonstrate wide variation in success of cohorts and important differences in the larval recruitment capacities of these two important but imperiled reef-building species.

Survivorship of standard versus modified posterior surgical approaches in metal-on-metal hip resurfacing.

ObjectivesMetal-on-metal hip resurfacing (MOMHR) is available as an alternative option for younger, more active patients. There are failure modes that are unique to MOMHR, which include loosening of the femoral head and fractures of the femoral neck. Previous studies have speculated that changes in the vascularity of the femoral head may contribute to these failure modes. This study compares the survivorship between the standard posterior approach (SPA) and modified posterior approach (MPA) in MOMHR. MethodsA retrospective clinical outcomes study was performed examining 351 hips (279 male, 72 female) replaced with Birmingham Hip Resurfacing (BHR, Smith and Nephew, Memphis, Tennessee) in 313 patients with a pre-operative diagnosis of osteoarthritis. The mean follow-up period for the SPA group was 2.8 years (0.1 to 6.1) and for the MPA, 2.2 years (0.03 to 5.2); this difference in follow-up period was statistically significant (p < 0.01). Survival analysis was completed using the Kaplan–Meier method. ResultsAt four years, the Kaplan–Meier survival curve for the SPA was 97.2% and 99.4% for the MPA; this was statistically significant (log-rank; p = 0.036). There were eight failures in the SPA and two in the MPA. There was a 3.5% incidence of femoral head collapse or loosening in the SPA and 0.4% in the MPA, which represented a significant difference (p = 0.041). There was a 1.7% incidence of fractures of the femoral neck in the SPA and none in the MPA (p = 0.108). ConclusionThis study found a significant difference in survivorship at four years between the SPA and the MPA (p = 0.036). The clinical outcomes of this study suggest that preserving the vascularity of the femoral neck by using the MPA results in fewer vascular-related failures in MOMHRs.Cite this article: Bone Joint Res 2014;3:150–4

No Differences Found in Bearing Related Hip Survivorship at 10–12 Years Follow-Up Between Patients With Ceramic on Highly Cross-Linked Polyethylene Bearings Compared to Patients With Ceramic on Ceramic Bearings

At a minimum follow-up of ten years we compared clinical and radiographic findings and survivorship in a cohort of 412 patients (447 hips) who received alumina on alumina CoC bearings to findings from a cohort of 216 patients (228 hips) with alumina on highly cross-linked polyethylene (HXLPE) bearings. All patients were operated for osteoarthritis. With bearing-related complications as endpoint, analysis showed no significant difference in survivorship between cohorts (99.8% for the CoC vs. 99.4% for HXLPE). In addition, there were no significant differences in clinical and radiographic findings between cohorts. We concluded that alumina on HXLPE bearings are a reasonable lower cost alternative to ceramic on ceramic bearing couples.

The effect of a collar and surface finish on cemented femoral stems: a prospective randomised trial of four stem designs

The optimal design for a cemented femoral stem remains a matter of debate. Over time, the shape, surface finish and collar have all been modified in various ways. A clear consensus has not yet emerged regarding the relative merits of even the most basic design features of the stem. We undertook a prospective randomised trial comparing surface finish and the effect of a collar on cemented femoral component subsidence, survivorship and clinical function. One hundred and sixty three primary total hip replacement patients were recruited prospectively and randomised to one of four groups to receive a cemented femoral stem with either a matt or polished finish, and with or without a collar. At two years, although there was a trend for increased subsidence in the matt collarless group, this was not statistically significant (p = 0.18). At a mean of 10.1 years follow-up, WOMAC scores for the surviving implants were good, (Range of means 89-93) without significant differences. Using revision or radiographic loosening as the endpoint, survivorship of the entire cohort was 93 % at 11 yrs, (CI 87-97 %). There were no significant differences in survivorship between the two groups with polished stems or the two groups with matt stems. A comparison of the two collarless stems demonstrated a statistically significant difference in survivorship between polished (100 %) and matt (88 %) finishes (p = 0.02). In the presence of a collar, surface finish did not significantly affect survivorship or function. Between the two collarless groups a polished surface conferred an improved survivorship.

Influence of coincident distal radius fracture in patients with hip fracture: single-centre series and meta-analysis

BackgroundHip and wrist fractures are the most common orthopaedic injuries. Combined hip and distal radius fractures are an important clinical and public health problem, since mobilisation and rehabilitation is challenging and likely to be prolonged in this setting. Few studies have explored the influence of an associated wrist fracture in patients with hip fracture. We present the largest series of patients with concomitant hip and wrist fractures. We perform the first meta-analysis of the literature on patients with concurrent hip and wrist fractures.Material and methodsIn this single-centre retrospective study we compared 88 consecutive patients with simultaneous hip and wrist fractures with 772 consecutive patients who suffered isolated hip fractures.ResultsPatients with the combined fracture were of a similar age compared to those with isolated hip fracture. There were a significantly higher proportion of women in the cohort with both hip and wrist fractures (female:male ratio of 9:1 versus 4:1 p < 0.0001). The combination fracture group had a greater length of hospitalisation (18 vs 13 days p < 0.0001). The survivorship of both groups was not significantly different even after adjustment for age and gender. Meta-analysis of the literature showed female preponderance, increased length of stay but no significant difference in survival in patients with concomitant hip and wrist fractures.ConclusionThe combination fracture occurs much more commonly in women and patients require a greater length of hospitalisation. The patients who sustained simultaneous hip and wrist fractures experienced no statistically significant difference in survivorship when compared to those who suffer isolated hip fractures. This is not withstanding the presence of two fractures. This difference in mortality did not reach statistical significance.Level of evidenceLevel III (retrospective comparative study).

Effect of inbreeding on survival, WSSV tolerance and growth at the postlarval stage of experimental full-sibling inbred populations of the Chinese shrimp Fenneropenaeus chinensis

Inbreeding effects on growth, survival and anti-WSSV (White Spot Syndrome Virus) traits were studied in experimental full-sibling inbred populations of Chinese shrimp Fenneropenaeus chinensis at three levels of inbreeding coefficient (F=0.25, F=0.375, F=0.50) from a Chinese shrimp selection program. The body weight of the control group (F≈0.00) was significantly different from those of the three levels of inbreeding groups at three postlarval stages (PL80, PL100 and PL140). At PL140, an increasing inbreeding depression of growth was observed with increasing inbreeding coefficient. The inbreeding depression was found to be −10.4% at F=0.25, −16.61% at F=0.375 and −23.68% at F=0.50. There was also a tendency for inbreeding depression for body weight to increase with age. The estimated coefficient of body weight of PL140 were −4.16%, −4.43% and −4.74% per 10% increase of inbreeding coefficient of F=0.25, F=0.375, F=0.50, respectively. During growout, inbreeding depression of survival ranged from −0.98% to −12.44%, although the effects were not significant. Over all levels of inbreeding the average inbreeding depression was found to be −5.95% for survival of PL80, −5.51% for PL100 and −6.71% for PL140. The estimated average inbreeding depression coefficient of survival ranged from −1.27% to −1.77% per 10% increase of inbreeding coefficient of F, lower than the estimate obtained for growth. The effects of inbreeding on survival time after challenge with White Spot Syndrome Virus (WSSV) were not significant, as there was no significant difference in survivorship among the control and the three levels of inbreeding coefficient groups. The inbreeding depression of the three levels ranged from −0.68% to −2.22%, and the estimated inbreeding depression coefficient of survival time ranged from −0.27% to −0.44% per 10% increase of inbreeding coefficient of F. This study demonstrates that inbreeding has a negative effect on the economic traits, especially on growth, thus highlighting the need to maximize the genetic diversity in selective breeding programs.

Is There a Role for Knee Arthrodesis With Modular Endoprostheses for Tumor and Revision of Failed Endoprostheses?

Knee arthrodeses are performed to treat infection after arthroplasty and tumors requiring extensive soft tissue resection. Many techniques have been described, but most have important disadvantages. Currently, endoprosthetic arthrodesis implants are available, but little is known about them. Our objective was to analyze a series of knee arthrodeses with a modular prosthetic system to evaluate (1) survivorship of the implant, (2) complications, (3) whether survivorship differed between arthrodeses done for primary tumor resection and revision reconstructions, and (4) whether survivorship differed based on the presence of previous infection or the use of a gastrocnemius flap. We present 32 patients with modular knee arthrodeses; arthrodeses were performed in 25 patients with tumors and in seven patients without tumors. There were 14 implants done at the time of tumor resection and 18 for revision of failed implants. Survivorship and complications were analyzed with Kaplan-Meier curves. Log-rank test was used for comparison between primary and revision implants, not infected and previously infected implants, and use or nonuse of a gastrocnemius flap. Survivorship of arthrodeses with modular endoprostheses was 50% and 25% at 5 and 10 years, respectively. There were nine infections (29%) and one implant fracture (3%). Amputation as final surgery was required in 8 patients (six owing to infection and two to oncologic failures). There was no significant difference in survivorship between arthrodeses done for primary tumor resection and as a salvage procedure for failed implants. No differences were found between patients with and without prior infection or with and without a gastrocnemius flap. Survivorship of a modular arthrodesis implant was 50% at 5 years owing to a high complication rate. Infection is the most common cause of failure of oncologic and revision implants. Implant fracture is a rare occurrence. Modular segmental arthrodesis provides a stable construct for patients in whom limb preservation is possible but a hinged device is contraindicated as a result of major muscle resection. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Survival analysis of total knee arthroplasty at a minimum 10 years’ follow-up: A multicenter French nationwide study including 846 cases

Survivorship for modern total knee arthroplasties (TKA) is not precisely known from large series, other than registries. The present retrospective study therefore analyzed 846 TKAs at a minimum 10 years' follow-up. Ten-year survivorship for TKAs in a multicenter study exceeds 90%, independently of design and level of prosthetic constraint. Eight hundred and twenty-eight patients (846 TKAs) were assessed on the Knee Society score. Mean age was 71 years (range, 41-93 years); 274 males and 554 females (67%); 496 patients (60%) were active; diagnosis was principally osteoarthritis (n=752 [89%]). Most TKAs were cemented (n=704 [83%]), replacing the patella (n=668 [79%]) and sacrificed the posterior cruciate ligament (PCL) (n=707 [84%]), 65% being posterior-stabilized and 35% ultracongruent, with fixed (39%) or mobile bearing (61%). At a minimum 10 years' follow-up, mean knee score rose from 35 (15-55) to 83 points (74-95), and functional score from 24 (5-45) to 74 points (60-90); mean flexion rose from 105° (25-125°) to 112° (25-125°). Mean hip-knee-ankle angle was 179.5° (169-189°). Sixty-three (7.5%) revision surgeries were required, mainly for loosening (n=18 [2%]) or infection (n=18 [1.8%]). Overall 10-year survivorship was 92% (95% CI: 0.90-0.94). There was no significant difference in survivorship according to implant design or PCL retention. Activity level correlated with revision rate; mechanical complications were more frequent in active and infectious complications in sedentary subjects. Revision was not more frequent in TKA aligned outside the 177-183° range. Ten-year TKA survivorship was 92%, independently of design and level of mechanical stress. Revision was mainly for infection or loosening, and not for greater than 3° axis misalignment. Mechanical complications were more frequent in younger and more active subjects, for whom therefore other treatment options or technical improvements should be sought. Level IV. Retrospective study.

Hybrid Total Knee Arthroplasty Revisited: Midterm Followup of Hybrid versus Cemented Fixation in Total Knee Arthroplasty

The optimal method of fixation in total knee arthroplasty is still debated. Hybrid total knee arthroplasty (TKA), with cemented tibial and cementless femoral components, is a proposed method of fixation to improve outcomes. Although several studies have shown favorable outcomes, there is still lack of consensus in the literature. We hypothesized that hybrid TKA yields similar clinical, radiographic, and survivorship results compared to fully cemented TKA. The clinical and radiographic outcomes of 304 cruciate retaining TKAs with minimum two-year followup, including 193 hybrid (mean followup of 4.1 years) and fully cemented TKAs (mean followup of 3.2 years) were evaluated. Knee society scores were similar between the two groups. The total number of femoral radiolucencies was also similar between the two groups, while a greater number of femoral Zone 4 radiolucencies were seen in the cemented group (9% versus 1.6%, P = 0.005). The hybrid group demonstrated a 99.2% survival rate of the femoral component out to seven years for aseptic loosening. No significant difference in survivorship was seen between the groups for all cause or aseptic failure at seven years. We conclude that hybrid fixation leads to similar intermediate-term outcomes as fully cemented components and remains a viable option in total knee arthroplasty.

Effect of the bacterium Serratia marcescens SCBI on the longevity and reproduction of the nematode Caenorhabditis briggsae KT0001

BackgroundExtensive research effort has advanced our understanding of Caenorhabditis as a model system, but its natural association with bacteria remains to be explored in an ecological context. Explored associations vary vastly from mutualistic to parasitic. Serratia marcescens has been shown to be pathogenic to Caenorhabditis with a fitness cost. The recent isolation of an entomopathogenic Caenorhabditis briggsae KT0001/S. marcescens SCBI association from the wild has allowed us to examine under laboratory conditions whether such an association poses a serious cost to Caenorhabditis as previously surmised for other Serratia.ResultsA fecundity table of Caenorhabditis briggsae KT0001 fed on S. marcescens SCBI and the control fed on E. coli OP50 is presented. We found no significant difference in survivorship or total fecundity between the S. marcescens SCBI fed and E. coli OP50 fed Caenorhabditis briggsae KT0001. Only the mean onset of reproduction was significantly different between the two groups with E. coli fed C. briggsae maturing earlier (2.12 days) than those fed on Serratia (2.42 days).ConclusionS. marcescens SCBI is not highly pathogenic to C. briggsae KT0001 indicating that the entomopathogenicity reported for this association may be beneficial for both the nematode and bacteria. In light of the fact that hitherto conducted experimental tests conform to widely held view that Serratia are highly pathogenic to Caenorhabditis, the absence of a high fitness cost for C. briggsae we report here may indicate that this entomopathogenic association is non-transient suggesting nematode/bacterial associations in the wild may vary greatly. Consequently, broad generalizations about nematode/bacterial associations should be interpreted with care.

Predicting Capacity Demand on Sanctuaries for African Chimpanzees (Pan troglodytes)

Wildlife sanctuaries rescue, rehabilitate, reintroduce, and provide life-long care for orphaned and injured animals. Understanding a sanctuary’s patterns in arrival, mortality, and projected changes in population size can help managers plan carefully for future needs, as well as illuminate patterns in source populations of wildlife. We studied these dynamics for chimpanzees (Pan troglodytes) in 11 sanctuaries of the Pan African Sanctuary Alliance (PASA). We analyzed historic demographic patterns and projected future population dynamics using an individual-based demographic model. From 2000 to 2006, the population in these sanctuaries has been growing at a rate of 15% per year. This growth is driven by arrivals of new individuals, with an average of 56 arrivals per year. The median age of the 760 chimpanzees living in these sanctuaries as of 2007 was 9 yr, with 76% of the population <15 yr. We found no significant difference in survivorship to age 20 between these chimpanzees and those maintained in North American accredited zoos. The size of the population in 20 yr is projected to be between 550 and 1800, depending on different assumptions about arrival and reintroduction rates. Projected shifts in age structure, including increases in the proportions of adolescent (9–19 yr of age) and older (35+) chimpanzees, may necessitate adjustments to management, veterinary care, and housing. This research illustrates how data on historic population dynamics can be modeled to inform future sanctuary capacity and management needs, allowing sanctuaries to plan better for their populations’ long-term care.

Mortality of Western Corn Rootworm Larvae on MIR604 Transgenic Maize Roots: Field Survivorship Has No Significant Impact on Survivorship of F1 Progeny on MIR604

Mortality of western corn rootworm, Diabrotica virgifera virgifera LeConte, larvae due to MIR604 transgenic corn, Zea mays L., expressing the modified Cry3A (mCry3A) protein relative to survivorship on corn with the same genetic background without the gene (isoline corn) was evaluated at three Missouri sites in both 2005 and 2006. We made these comparisons by using wild-type western corn rootworm at three different egg densities (6,000, 3,000, and 1,500 eggs per m) so that the role of density-dependent mortality would be known. The mortality due to the mCry3A protein was 94.88% when averaged across all environments and both years. Fifty percent emergence of beetles was delayed approximately 5.5 d. Beetles were kept alive and their progeny evaluated on MIR604 and isoline corn in the greenhouse to determine whether survivorship on MIR604 in the field for one generation increased survivorship on MIR604 in the greenhouse in the subsequent generation. There was no significant difference in survivorship on MIR604 in greenhouse assays between larvae whose parents survived isoline and larvae whose parents survived MIR604 in the field the previous generation, indicating that many susceptible beetles survived MIR604 in the field the previous season along with any potentially resistant beetles. The data are discussed in terms of rootworm insect resistance management.