RESUMEN
In revision operations, ceramic heads of modular hip implants can be replaced. As the surface of the stem taper can be damaged, additional adapter sleeves are applied. The components are usually connected manually by the surgeon in a one-step procedure by hammer impacts. In this study, we investigated a two-step joining procedure with reproducible impaction force. First, the adapter sleeve and head were joined quasi-statically with a force of 2 kN using an assembly device. In the second step, these components were applied to the stem taper using a pulse-controlled instrument. For reference, the joints were assembled according to standard conditions using a tensile testing machine. An average pull-off force of 1309 ± 201 N was achieved for the components joined by the instrument, and the average measured values for the components joined by the testing machine were 1290 ± 140 N. All specimens achieved a force >350 N when released and therefore met the acceptance criterion defined for this study. This study showed that a modified procedure in two steps with a defined force has a positive effect on the reproducibility of the measured joining forces compared to previous studies.
RESUMEN
Modern hip implants have a modular design. In case of wear or other damage it allows surgeons to change the tribological partners, i.e., the acetabular liner and femoral ball. In both revision and primary surgery, the secure joining of the implant components is important for the success of the operation. The two components, namely the ceramic liner and hip cup, are connected via a conical press connection and should be concentrically aligned to avoid chipping. Malseated liners can reduce the life span in situ. The amount of the joining force, which is usually applied via a hammer, depends on the surgeon. In this study, an alternative joining method for acetabular ceramic liners in hip cups was investigated, which intends to make the process more reproducible and thus safer. For this purpose, a handpiece was used to apply a defined force impulse of 4 kN. For the concentric alignment of a ceramic liner in the hip cup, an adapter was developed based on findings via a qualitative finite element (FE) analysis. Insertion and pushout tests of the acetabular cup-liner connection were performed in the laboratory with the new instrument (handpiece with the connected adapter) to evaluate the functionality of the instrument and the reproducibility of the new insertion method. For comparison, liners and acetabular cups were joined using a testing machine according to the standard. The presented results demonstrate the technical proof-of-concept of the new joining method under laboratory conditions. They meet the acceptance criteria of established manufacturers, which proves the equivalency to proven methods for joining modular implant components. To verify the improvement of the new joining method compared to the conventionally used joining method, an application-oriented study with different surgeons and the new joining instrument under clinical conditions is necessary.
RESUMEN
BACKGROUND: Conservative scoliosis therapy in the form of assisted physiotherapeutic scoliosis exercises is supplemented by self-contained training at home, depending on the approach (eg, Schroth, the Scientific Exercises Approach to Scoliosis). Complex exercises, lack of awareness of the importance of training, and missing supervision by therapists often lead to uncertainty and reduced motivation, which in turn reduces the success of home-based therapy. Increasing digitalization in the health care sector offers opportunities to close this gap. However, research is needed to analyze the requirements and translate the potential of digital tools into concrete solution concepts. OBJECTIVE: The aim of this study is to evaluate the potential for optimizing home-based scoliosis therapy in terms of motivation, assistive devices, and digital tools. METHODS: In collaboration with the Institute of Physiotherapy at the Jena University Hospital, a survey was initiated to address patients with scoliosis and physical therapists. A digital questionnaire was created for each target group and distributed via physiotherapies, scoliosis forums, the Bundesverband für Skoliose Selbsthilfe e. V. newsletter via a link, and a quick response code. The survey collected data on demographics, therapy, exercise habits, motivation, assistive devices, and digital tools. Descriptive statistics were used for evaluation. RESULTS: Of 141 survey participants, 72 (51.1%; n=62, 86.1%, female; n=10, 13.9%, male) patients with scoliosis with an average age of 40 (SD 17.08) years and 30 scoliosis therapists completed the respective questionnaires. The analysis of home-based therapy showed that patients with scoliosis exercise less per week (2 times or less; 45/72, 62.5%) than they are recommended to do by therapists (at least 3 times; 53/72, 73.6%). Patients indicated that their motivation could be increased by practicing together with friends and acquaintances (54/72, 75%), a supporting therapy device (48/72, 66.7%), or a digital profile (46/72, 63.9%). The most important assistive devices, which are comparatively rarely used in home-based therapy, included balance boards (20/72, 27.8%), wall bars (23/72, 31.9%), mirrors (36/72, 50%), and long bars (40/72, 55.6%). Therapists saw the greatest benefit of digital tools for scoliosis therapy in increasing motivation (26/30, 87%), improving home therapy (25/30, 83%), monitoring therapy progress (25/30, 83%), and demonstrating exercise instructions (24/30, 80%). CONCLUSIONS: In this study, we investigated whether there is any potential for improvement in home-based scoliosis therapy. For this purpose, using online questionnaires, we asked patients with scoliosis and therapists questions about the following topics: exercise habits, outpatient and home-based therapy, motivation, supportive devices, and digital tools. The results showed that a lack of motivation, suitable training equipment, and tools for self-control leads to a low training workload. From the perspective of the patients surveyed, this problem can be addressed through community training with friends or acquaintances, a supportive therapy device, and digital elements, such as apps, with training instructions and user profiles.
RESUMEN
Minimally invasive surgery is increasingly used in many medical operations because of the benefits for the patients. However, for the surgeons, accessing the situs through a small incision or natural orifice comes with a reduction of the degrees of freedom of the instrument. Due to friction of the mechanical coupling, the haptic feedback lacks sensitivity that could lead to damage of the tissue. The approach of this work to overcome these problems is to develop a control concept for position control and force estimation with shape memory alloys (SMA) which could offer haptic feedback in a novel handheld instrument. The concept aims to bridge the gap between manually actuated laparoscopic instruments and surgical robots. Nickel-titanium shape memory alloys are used for actuation because of their high specific energy density. The work includes the manufacturing of a functional model as a proof of concept comprising the development of a suitable forceps mechanism and electronic circuit for position control and gripping force measurement, as well as designing an ergonomic user interface with haptic force feedback.
RESUMEN
The biomaterials used to maintain or replace functions in the human body consist mainly of metals, ceramics or polymers. In orthopedic surgery, metallic materials, especially titanium and its alloys, are the most common, due to their excellent mechanical properties, corrosion resistance, and biocompatibility. Aside from the established Ti6Al4V alloy, shape memory materials such as nickel-titanium (NiTi) have risen in importance, but are also discussed because of the adverse effects of nickel ions. These might be reduced by specific surface modifications. In the present in vitro study, the osteoblastic cell line MG-63 as well as primary human osteoblasts, fibroblasts, and macrophages were cultured on titanium alloys (forged Ti6Al4V, additive manufactured Ti6Al4V, NiTi, and Diamond-Like-Carbon (DLC)-coated NiTi) to verify their specific biocompatibility and inflammatory potential. Additive manufactured Ti6Al4V and NiTi revealed the highest levels of metabolic cell activity. DLC-coated NiTi appeared as a suitable surface for cell growth, showing the highest collagen production. None of the implant materials caused a strong inflammatory response. In general, no distinct cell-specific response could be observed for the materials and surface coating used. In summary, all tested titanium alloys seem to be biologically appropriate for application in orthopedic surgery.
RESUMEN
Sequence conservation among resistance genes (R genes) was exploited to identify 47 R gene analogues (RGAs) from sugar beet (Beta vulgaris L.). Using degenerate primers, 11 RGAs were amplified from genomic DNA and 7 from leaf or beet cDNA. Twenty-nine were selected from an EST sequencing program. Twenty-one RGAs contained structures similar to the nucleotide binding site (NBS)--leucine rich repeat (LRR) domain, a motif commonly found in several R genes. Among the remaining RGAs, 19 revealed similarity to the serine (threonine) protein kinase domain of R genes, 4 showed features related to the LRR region of the rice disease resistance gene Xa21, 1 RGA resembled the sugar beet nematode resistance gene Hs1pro-1, and 2 had homologies to other gene products associated with disease resistance. For 20 EST-derived RGAs, transcript levels were compared in leaf and root tissue revealing organ-specific transcription in 7 cases. Thirty-three RGAs were spread over all nine sugar beet chromosomes, except for a cluster of nine closely linked RGAs on chromosome 7. The analysis of linkage between RGAs and loci for rhizomania and Cercospora resistance identified alleles associated with resistance in both cases.
