European river typologies fail to capture diatom, fish, and macrophyte community composition

Typology systems are frequently used in applied and fundamental ecology and are relevant for environmental monitoring and conservation. They aggregate ecosystems into discrete types based on biotic and abiotic variables, assuming that ecosystems of the same type are more alike than ecosystems of different types with regard to a specific property of interest. We evaluated whether this assumption is met by the Broad River Types (BRT), a recently proposed European river typology system, that classifies river segments based on abiotic variables, when it is used to group biological communities. We compiled data on the community composition of diatoms, fishes, and aquatic macrophytes throughout Europe and evaluated whether the composition is more similar in site groups with the same river type than in site groups of different river types using analysis of similarities, classification strength, typical species analysis, and the area under zeta diversity decline curves. We compared the performance of the BRT with those of four region-based typology systems, namely, Illies Freshwater Ecoregions, the Biogeographic Regions, the Freshwater Ecoregions of the World, and the Environmental Zones, as well as spatial autocorrelation (SA) classifications. All typology systems received low scores from most evaluation methods, relative to predefined thresholds and the SA classifications. The BRT often scored lowest of all typology systems. Within each typology system, community composition overlapped considerably between site groups defined by the types of the systems. The overlap tended to be the lowest for fishes and between Illies Freshwater Ecoregions. In conclusion, we found that existing broad-scale river typology systems fail to delineate site groups with distinct and compositionally homogeneous communities of diatoms, fishes, and macrophytes. A way to improve the fit between typology systems and biological communities might be to combine segment-based and region-based typology systems to simultaneously account for local environmental variation and historical distribution patterns, thus potentially improving the utility of broad-scale typology systems for freshwater biota.

Posterior tibial plateau fracture treatment with the new WAVE posterior proximal tibia plate: feasibility and first results

INTRODUCTION

Operative management of posterior tibial plateau fractures (PTPF) remains challenging. The treatment goal is to restore the alignment and articular congruence, and providing sufficient stability which allows early mobilization. The purpose of this study was to assess the feasibility and safety of the newly developed WAVE posterior proximal tibia plate.

METHODS

Between Oct 2017 and Jun 2020, 30 adult patients with a tibial plateau fracture and posterior involvement were selected for treatment with a WAVE posterior proximal tibia plate. Patient reported outcome was assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS) at time of injury (pre-injury) and at 1-year follow-up. Radiological outcome was evaluated with CT-imaging.

RESULTS

Twenty-eight patients were eligible for treatment with the new implant (3 'one-column', 10 'two column' and 15 'three-column' fractures), whereas in 2 patients anatomical fit was insufficient. KOOS results showed fair outcome scores at 1 year, with a large negative impact compared to pre-injury levels; however, a trend towards better results compared to a previous PTPF reference cohort. Radiological follow-up showed insufficient posterolateral buttress in two cases and residual articular step-off (> 2 mm) in seven patients, of which five were classified as three column fractures.

CONCLUSION

Management of PTPF using the WAVE posterior proximal tibia plate is feasible and safe with satisfactory clinical and radiological results after 1 year. Nevertheless, there is a learning curve regarding optimal implant positioning to achieve the maximum benefit of the implant.

LEVEL OF EVIDENCE

4.

Poor sporting abilities after tibial plateau fractures involving the posterior column: how can we do better?

PURPOSE

Tibial plateau fractures with the involvement of the posterior column are an important prognostic factor towards poor functional outcome. We aimed to assess the sporting abilities postoperatively with special emphasis on the type of sports and sport-specific movements, as well as time needed to resume sports, restricting factors in sports engagement, and patient satisfaction. We aimed to provide prognostic information on return to sports.

METHODS

Demographic, clinical and radiological variables were retrospectively collected from 82 multicentric patients between 2014 and 2016. Prospectively, sporting abilities before and after surgery were determined using questionnaires at a mean follow-up of 33 months postoperatively.

RESULTS

Involvement in sports significantly decreased, with only 68.4% of patients resuming sports (p < 0.001). The mean time needed to partially or fully resume sports was 6-9 and 9-12 months, respectively. The ability to resume at the pre-injury level of effort and performance was 22% and 12%, respectively. Restricting factors were pain (66%), fear of re-injury (37%), limited range of motion (26%), and instability (21%). The majority (59%) of patients were unsatisfied with their physical abilities. Significantly worse outcomes were observed in patients playing high-impact sports, experiencing knee pain during physical activity, suffering from extension/valgus or flexion/varus trauma.

CONCLUSIONS

Tibial plateau fractures with the involvement of the posterior column significantly hamper the patients' sporting abilities, leaving the majority of patients unsatisfied. Preoperative counseling about prognosis, setting realistic expectations, optimizing rehabilitation and pain management postoperatively, and advising low-impact sports might improve engagement in physical activities and emotional impact on patients.

LEVEL OF EVIDENCE

3.

Implant removal of osteosynthesis: the Dutch practice. Results of a survey

Background

The aim of this survey study was to evaluate the current opinion and practice of trauma and orthopaedic surgeons in the Netherlands in the removal of implants after fracture healing.

Methods

A web-based questionnaire consisting of 44 items was sent to all active members of the Dutch Trauma Society and Dutch Orthopaedic Trauma Society to determine their habits and opinions about implant removal.

Results

Though implant removal is not routinely done in the Netherlands, 89% of the Dutch surgeons agreed that implant removal is a good option in case of pain or functional deficits. Also infection of the implant or bone is one of the main reasons for removing the implant (> 90%), while making money was a motivation for only 1% of the respondents. In case of younger patients (< 40 years of age) only 34% of the surgeons agreed that metal implants should always be removed in this category. Orthopaedic surgeons are more conservative and differ in their opinion about this subject compared to general trauma surgeons (p = 0.002). Though the far majority removes elastic nails in children (95%).

Most of the participants (56%) did not agree that leaving implants in is associated with an increased risk of fractures, infections, allergy or malignancy. Yet in case of the risk of fractures, residents all agreed to this statement (100%) whereas staff specialists disagreed for 71% (p < 0.001). According to 62% of the surgeons titanium plates are more difficult to remove than stainless steel, but 47% did not consider them safer to leave in situ compared to stainless steel. The most mentioned postoperative complications were wound infection (37%), unpleasant scarring (24%) and postoperative hemorraghe (19%).

Conclusion

This survey indicates that there is no general opinion about implant removal after fracture healing with a lack of policy guidelines in the Netherlands. In case of symptomatic patients a majority of the surgeons removes the implant, but this is not standard practice for every surgeon.