Physiological Responses of Crotalaria spp. to the Presence of High Aluminum Availability in the Soil.

Brazilian soils are predominantly rich in aluminum, which becomes mobile at pH < 5, affecting sensitive plants; however, some species have developed aluminum tolerance mechanisms. The purpose of this study was to compare the physiological responses of Crotalaria genus species, family Fabaceae, which have the ability to associate with nitrogen-fixing bacteria under the influence of Al3+ in the soil. The soil used was Oxisol; the experimental design was in randomized blocks in a factorial scheme (2 × 3): soil factor (available toxic aluminum content; correction of dolomitic limestone-MgCO3) and species factor (C. juncea; C. spectabilis; C. ochroleuca); cultivated within 43, 53, and 53 days, respectively, with five replications; 30 experimental samples. Mass and length, pigments, gas exchange, and changes in nitrogen metabolism were evaluated. C. juncea showed a higher concentration of amino acids in the leaves, internal carbon, and stomatal conductance in soil with Al3+, as well as higher production of ureides, allantoinic acid, allantoic acid, proteins, and amino acids in the nodules, with 78% of the Al3+ accumulation occurring in the roots. C. ochroleuca demonstrated greater shoot length and nodule number production in limed soil; in soil with Al3+, it showed a 91% increase in chlorophyll a content and 93% in carotenoids. C. spectabilis showed a 93% increase in ureide production in the leaves in soil with Al3+.

A Dilemma in the Management of Distal Tibia Fractures Solved by Minimally Invasive Percutaneous Plate Osteosynthesis Technique: A Prospective Study.

Introduction Managing distal tibia fractures is challenging for trauma surgeons because of their peculiar anatomy with less soft tissue coverage and poor blood supply. There are various treatment options for distal tibia fractures such as open reduction and plating, minimally invasive percutaneous plate osteosynthesis, and intramedullary interlocking nailing. Open reduction and internal fixation can lead to excessive soft tissue dissection and devascularization of fracture fragments. We conducted a study on the functional outcome of distal tibia fractures treated by biological fixation with minimally invasive percutaneous plate osteosynthesis. Methods A total of 23 patients with distal one-third tibia fractures, fulfilling the inclusion criteria, who were treated at St. John's Medical College Hospital with minimally invasive percutaneous plate osteosynthesis between November 2020 and November 2022 were studied using the American Orthopaedic Foot & Ankle Society (AOFAS) score at six weeks, three months, and six months postoperative follow-up. Results This study included 17 males and six females. The mean age of the study participants was 43.78 years, with most of the participants being in the age group between 51 and 60 years (29.2%, n = 7). All the study participants were employed. The mean operative time was two hours and 10 minutes. The mean duration for the radiological union was 22 weeks. The mean AOFAS score at six months was 92.43 + 5.696. There was only one case of superficial infection, which was treated with intravenous antibiotics. There were no cases of malunion/nonunion. Conclusion Minimally invasive percutaneous plate osteosynthesis is an effective treatment for distal tibia fractures avoiding most of the complications such as wound dehiscence and malunion/nonunion involved in conventional open reduction and internal fixation with plating. Therefore, we recommend this technique for all distal tibia fractures.

Hydroxyapatite-Coated Femoral Stems in Primary Total Hip Arthroplasty: An Updated Meta-Analysis.

BACKGROUND: Most primary total hip arthroplasties (THAs) performed in the United States utilize cementless fixation with porous or hydroxyapatite (HA) coating. A previous meta-analysis comparing HA-coated versus non-HA-coated stems in primary THA published in 2013 found no significant difference between the 2. However, an updated analysis of the current literature is needed to assess the potential benefit of HA-coated stems in primary THA. METHODS: Various libraries were searched through May 2022 according to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Studies included were randomized controlled trials comparing HA-coated femoral stems to non-HA-coated stems in primary THA. Outcomes included Harris Hip Score (HHS), endosteal bone formation, radiolucent lines, linear wear rate, revision for aseptic loosening, thigh pain, and heterotopic ossification. RESULTS: There were significantly fewer revisions for aseptic loosening (P = .004) and decreased postoperative thigh pain (P = .03) for patients who have with HA-coated stems. There was no significant difference in HHS (P = .20), endosteal bone formation (P = .96), radiolucent lines (P = .75), linear wear rate (P = .41), or heterotopic ossification (P = .71) between HA-coated and non-HA-coated stems. CONCLUSION: We found that HA-coated femoral stems in primary THA led to significantly fewer stem revisions for aseptic loosening and less postoperative thigh pain compared to non-HA-coated stems. These findings suggest HA-coated femoral stems should be preferred over non-HA-coated femoral stems in primary THA.

Association Between Surface Modifications for Biologic Fixation and Aseptic Loosening of Uncemented Total Knee Arthroplasties.

BACKGROUND: Various surface modifications are used in uncemented total knee arthroplasties (TKAs) to enhance bony ingrowth and longevity of implants. This study aimed to identify which surface modifications are used, whether they are associated with different revision rates for aseptic loosening, and which are underperforming compared to cemented implants. METHODS: Data on all cemented and uncemented TKAs used between 2007 and 2021 were obtained from the Dutch Arthroplasty Register. Uncemented TKAs were divided into groups based on their surface modifications. Revision rates for aseptic loosening and major revisions were compared between groups. Kaplan-Meier, Competing-Risk, Log-rank tests, and Cox regression analyses were used. In total, 235,500 cemented and 10,749 uncemented primary TKAs were included. The different uncemented TKA groups included the following: 1,140 porous-hydroxyapatite (HA); 8,450 Porous-uncoated; 702 Grit-blasted-uncoated; and 172 Grit-blasted-Titanium-nitride (TiN) implants. RESULTS: The 10-year revision rates for aseptic loosening and major revision of the cemented TKAs were 1.3 and 3.1%, and for uncemented TKAs 0.2 and 2.3% (porous-HA), 1.3 and 2.9% (porous-uncoated), 2.8 and 4.0% (grit-blasted-uncoated), and 7.9% and 17.4% (grit-blasted-TiN), respectively. Both type of revision rates varied significantly between the uncemented groups (log-rank tests, P < .001, P < .001). All grit-blasted implants had a significantly higher risk of aseptic loosening (P < .01), and porous-uncoated implants had a significantly lower risk of aseptic loosening than cemented implants (P = .03) after 10 years. CONCLUSION: There were 4 main uncemented surface modifications identified, with different revision rates for aseptic loosening. Implants with porous-HA and porous-uncoated had the best revision rates, at least equal to cemented TKAs. Grit-blasted implants with and without TiN underperformed, possibly due to the interaction of other factors.

Fretting stimulation enhances bone growth at the interface between hydroxyapatite coating and bone.

Biologically fixed arthroplasty is limited in its development by the long postoperative recovery time and the low quality of solidity of the fixed interface in the short postoperative period. Therefore, fretting stimulation is used to accelerate the combination between bone tissue and the biological fixation interface of artificial joint prostheses. The effects of different compression loads and tangential micro-motion amplitude on the growth rate of bone tissue and the firm quality of fixation interface were studied by using two kinds of micro-motion stimuli: compression and tangential micro-motion. The mechanism of micro-motion stimulation to promote bone growth at the fixation interface was revealed. The results of binding force detection of biological fixation interface and bone tissue section staining showed that the bone tissue and hydroxyapatite coating interface had the most tendency to produce new bone tissue under compression load of 4 N. In the tangential fretting environment, the tangential fretting amplitude of ± 40 µm and the normal load of 7.5 N were the most conducive to bone growth, making the combination of bone tissue and titanium alloy prosthesis coated with hydroxyapatite more firm. The study is important for accelerating the integration and shortening the rehabilitation time after artificial joint replacement.

Safe corridors for external skeletal fixator pin placement in feline long bones.

OBJECTIVES: External skeletal fixation is an established technique in cats for biological fixation of long bone fractures, stabilisation of the joints, and treatment of shearing injuries and angular deformities. As appropriate and accurate pin insertion is imperative for a successful outcome, knowledge of topographic anatomy and areas that are safe (safe corridors) for pin placement is integral to successful surgery. At present, however, safe corridors have not been determined fully in feline orthopaedics, with surgeons having to rely on knowledge based on canine orthopaedics. This study was performed to determine safe corridors for pin placement in feline long bones. METHODS: The limbs of six feline cadavers were frozen. Only limbs with no history of orthopaedic conditions were used. Transverse sections through the limbs were examined, and anatomical structures were determined in relation to the bone. These structures were compared with those of the contralateral limbs, which were dissected for topographic assessment. Safe corridors were defined as topographic areas where no vital structures, muscles or joints were present. RESULTS: Examination of the humerus revealed safe corridors at its proximal craniolateral aspect and on the medial and lateral humeral condyles. Safe corridors of the antebrachium were identified on the lateral aspect of the olecranon, the distal two-thirds of the medial antebrachium and the distal third of the lateral antebrachium. Safe corridors in the femur consisted of a small area lateral to and just below the major trochanter, and on the medial and lateral femoral condyles. Evaluation of the tibia revealed safe corridors on the medial aspect of the entire tibia, the cranial aspect of the proximal tibia on the tibial crest and the area just proximal to the lateral malleolus. CONCLUSIONS AND RELEVANCE: Safe corridors for pin placement during external skeletal fixation in feline limbs differed from those in canine limbs. Knowledge of canine anatomy may be inapplicable to pin placement in feline limbs undergoing external skeletal fixation.

Resource Allocation During the Transition to Diazotrophy in Klebsiella oxytoca.

Free-living nitrogen-fixing bacteria can improve growth yields of some non-leguminous plants and, if enhanced through bioengineering approaches, have the potential to address major nutrient imbalances in global crop production by supplementing inorganic nitrogen fertilisers. However, nitrogen fixation is a highly resource-costly adaptation and is de-repressed only in environments in which sources of reduced nitrogen are scarce. Here we investigate nitrogen fixation (nif) gene expression and nitrogen starvation response signaling in the model diazotroph Klebsiella oxytoca (Ko) M5a1 during ammonium depletion and the transition to growth on atmospheric N2. Exploratory RNA-sequencing revealed that over 50% of genes were differentially expressed under diazotrophic conditions, among which the nif genes are among the most highly expressed and highly upregulated. Isotopically labelled QconCAT standards were designed for multiplexed, absolute quantification of Nif and nitrogen-stress proteins via multiple reaction monitoring mass spectrometry (MRM-MS). Time-resolved Nif protein concentrations were indicative of bifurcation in the accumulation rates of nitrogenase subunits (NifHDK) and accessory proteins. We estimate that the nitrogenase may account for more than 40% of cell protein during diazotrophic growth and occupy approximately half the active ribosome complement. The concentrations of free amino acids in nitrogen-starved cells were insufficient to support the observed rates of Nif protein expression. Total Nif protein accumulation was reduced 10-fold when the NifK protein was truncated and nitrogenase catalysis lost (nifK 1 - 1 203), implying that reinvestment of de novo fixed nitrogen is essential for further nif expression and a complete diazotrophy transition. Several amino acids accumulated in non-fixing ΔnifLA and nifK 1 - 1203 mutants, while the rest remained highly stable despite prolonged N starvation. Monitoring post-translational uridylylation of the PII-type signaling proteins GlnB and GlnK revealed distinct nitrogen regulatory roles in Ko M5a1. GlnK uridylylation was persistent throughout the diazotrophy transition while a ΔglnK mutant exhibited significantly reduced Nif expression and nitrogen fixation activity. Altogether, these findings highlight quantitatively the scale of resource allocation required to enable the nitrogen fixation adaptation to take place once underlying signaling processes are fulfilled. Our work also provides an omics-level framework with which to model nitrogen fixation in free-living diazotrophs and inform rational engineering strategies.

Assessment of Early Biological Fixation of Cementless Tapered-Wedge Stems Using Digital Tomosynthesis.

BACKGROUND: We aimed to compare radiographic and digital tomosynthesis assessments of early biological fixation of a cementless stem in primary total hip arthroplasty and to investigate the factors associated with early biological fixation. METHODS: Seventy-three patients underwent total hip arthroplasty using cementless short tapered-wedge stems. Both radiography and digital tomosynthesis were performed at 6 weeks and 3, 6, 12, and 24 months after surgery. The presence of spot welds (SW) was evaluated at each postoperative period to assess biological fixation between the stem and the femur. The area of contact between the femur and the stem was divided into seven zones based on Gruen's zone classification. RESULTS: All 73 patients had no SW 6 weeks after surgery on radiography and digital tomosynthesis. Three months postoperatively, there was no SW on radiography; however, digital tomosynthesis revealed SW in 31 (42%) patients. Six months postoperatively, radiography showed 22 SW in 18 (24.7%) patients and digital tomosynthesis showed 94 SW in 48 patients (65.8%). CONCLUSION: Digital tomosynthesis detected biological fixation between the stem and femur earlier than radiography; biological fixation may appear within 3 months after surgery.

3D printed chitosan-gelatine hydrogel coating on titanium alloy surface as biological fixation interface of artificial joint prosthesis.

To improve the fixation of the prosthesis-bone interface and to prevent postoperative infection, a novel antimicrobial hydrogel coating is designed as the biological fixation interface of the artificial joint prosthesis. Antimicrobial chitosan (CS) and gelatine (GT) were used as bioinks to print a CS-GT hydrogel coating with reticulated porous structure on the titanium alloy substrate by 3D printing technology. The experimental results show that the 7CS-10GT hydrogel coating has a macro-grid structure and honeycomb micro-network structure, excellent hydrophilicity (35.64°), high mechanical strength (elastic modulus 0.92 MPa) and high bonding strength (3.36 MPa) with the titanium alloy substrate. In addition, the antimicrobial effect of 7CS-10GT hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is enhanced after immersion in nano­silver. Moreover, the 7CS-10GT hydrogel displays good cell compatibility and supports proliferation of NIH-3 T3 cells. In summary, the 3D printed CS-GT antimicrobial hydrogel coating provides an ideal microenvironment for cell adhesion and bone growth due to the dual-scale porous network structure, good hydrophilicity and biocompatibility, thus promoting rapid fixation of the bone interface. This technology opens a new possibility for this biological fixation interface in artificial joint replacement.

Interprosthetic femoral fractures managed with modern distal femoral locking plates: 10 years' experience at a UK major trauma centre.

INTRODUCTION: Interprosthetic femoral fractures (IFF) are rare but increasing with an ageing population. Operative management is challenging and there is currently a paucity of outcome data in literature. The purpose of this study was to evaluate outcomes of IFFs managed with modern distal femoral locking plates, in a larger sample size than previously published. METHOD: This retrospective study reviewed 49 closed IFFs in 48 patients at a major trauma center from 2009 to 2019 occurring between previous total hip arthroplasty (n=38), hemi hip arthroplasty (n=3), dynamic hip screw (n=6) or cephalomedullary nail (n=2) and total knee arthroplasty. They were managed with Minimally Invasive Plate Osteosynthesis (MIPO) employing modern biological fixation techniques and stabilised with VA-LCP Condylar (Synthes; n=28) or Peri-Loc (S&N; n=21) plate. Clinical and radiographic outcomes were measured. RESULTS: The majority of fractures were in female patients (80%), who were elderly (average 83 years), and comorbid (55% ASA grade 3 or 4). Most fractures were Pires type IIA and OTA/AO type 33A. Average plate spanning femur was 16 holes, with average working length of 6 holes. 86% had unrestricted weight bearing immediately post operatively. 31 fractures reached radiological (n=25) or clinical (n=6) union. 13 patients died with 2 lost to follow up. There were 3 non-unions, with implant failure occurring before 4 months in all 3. We present a union rate of 91% (n=31/34). CONCLUSION: IFFs are occurring with increasing frequency in a frail elderly population. In patients with IFFs, MIPO and biological fixation techniques using modern distal femoral locking plates can achieve high rate of union when combined with immediate unrestricted weight bearing postoperatively.

Intramedullary nailing of adult forearm fractures: Results and complications.

INTRODUCTION: The aim of this study was to evaluate the clinical and radiological results of adult forearm fractures treated with interlocking intramedullary nailing. METHODS: This retrospective study included 21 patients who were treated with intramedullary interlocking nailing for forearm fractures between January 2010 and September 2017. All patients were treated with intramedullary forearm nails designed to allow interfragmentary compression. The medical records and radiographs of all patients were evaluated. Fractures were classified according to the AO/OTA classification system by analyzing the radiographs. Union time, union rate, clinical outcome, and complications were evaluated. RESULTS: Primary intramedullary osteosynthesis was performed in 17 patients with forearm shaft fractures. The average union time was 10 weeks (range, 8-16 weeks) in the primary osteosynthesis cohort. Secondary intramedullary osteosynthesis was performed in four patients following the removal of plates and screws due to nonunions. For this group of patients, bone union took an average of 17 weeks (range 8-24 weeks). The overall union rate was 95.24% in the 21 forearm fractures which were treated with an intramedullary interlocking nail with a compression screw that allows interfragmentary compression to be obtained. Overall complications included one nonunion, one postoperative rupture of the extensor pollicis longus tendon, and 1 postoperative transitory radial nerve palsy. CONCLUSIONS: Intramedullary interlocking nailing with a compression screw is an alternative method of fixation for treating adult forearm fractures and provides good clinical outcomes with reliable union rates.

Biofixation of atmospheric nitrogen in the context of world staple crop production: Policy perspectives.

The extensive use of nitrogen (N) fertilizers implicates a paradox: while fertilizers ensure the supply of a large amount of food, they cause negative environmental externalities, including reduced biodiversity, and eutrophic streams and lakes. Moreover, such fertilizers may also result in a major public health hazard: increased antibiotic resistance. This article discusses the critical implications of perturbations in N cycle caused by excessive use of fertilizers and resulting policy implications as they relate to ecosystem services. While there are solutions such as cover crops, these solutions are expensive and inconvenient for farmers. We advocate the use of biological fixation (BF) for staple crops-microbiome mediated natural supply of fixed N. This would involve engineering a microbiome that can be grown cheaply and at industrial scale. Fertilizers resulting from such innovation are termed as "biofertilizers" in this article. Following a qualitative cost-benefit analysis broken down by key stakeholders and a quick exploration of policy frameworks as they relate to the advancement of biofertilizers, we propose a practical pathway of where and how research investments should be directed to make such a solution feasible. We make five policy recommendations for decision-makers to facilitate a successful trajectory for this solution: (1) Future agricultural science should seek to understand how BF might be employed as a practical and efficient strategy. This effort would require that industry and the government partner to establish a pre-competitive research laboratory equipped with the latest state-of-the-art technologies that conduct metagenomic experiments to reveal signature microbiomes and form novel symbiotic connections. (2) To have a smooth ride in the market, ag-bio companies should: (i) create awareness among farmers; (ii) impart skills to farmers in testing and using biofertilizers, and (iii) conduct extensive field tests and more research in studying the scalability potential of such fertilizers. (3)The United States Department of Agriculture (USDA) and state governments should provide research and development (R&D) tax credits to biotech companies specifically geared towards R&D investments aimed at increasing the viability of BF and microbiome engineering. (4) To control agricultural pollution in the biosphere, federal governments should consider passing a Clean Agriculture Act (CAA), including a specific clause that regulate the use of chemical fertilizers. (5) Governments and the UN Food and Agriculture Organization (FAO) should coordinate Biological Advanced Research in Agriculture (BARA)-a global agricultural innovation initiative for investments and research in biological fixation and ethical, legal, and social implications of such innovation. While biological fixation will be central in BARA, we envision it to conduct research around other agricultural innovations as well, such as increasing photosynthetic efficiency.

Total hip arthroplasty utilizing an uncemented, flat, tapered stem with a reduced distal profile.

BACKGROUND: The aim of this study was to report the midterm results of an uncemented, flat, and tapered femoral stem with a reduced distal profile. METHODS: 219 total hip arthroplasties were performed using this stem between March 2007 and October 2012. Survival, radiographs, and modified Harris Hip Scores were analyzed. RESULTS: Twenty-two (11.1%) patients died from comorbidities but retained their hips; 18 (9.1%) patients were lost to follow-up. Of the remaining 179 hips, all stems remained in situ at a median follow-up of 8.4 (7.0-9.3) years. There was 97.5% (95% CI: 95.1-99.9) survival for all-cause revision with 4 hips revised for instability. Early stem subsidence was identified in 2 patients within 3 months postoperative measured at 4 mm in patient 1 and 3 mm in patient 2. Long-term radiographic follow-up showed 2 hips with incomplete radiolucencies but no evidence of stress shielding, osteolysis, or subsidence among examined hips (n = 93). Spot welding and cortical hypertrophy were present in 58 (62.4%) and 50 (53.8%) hips, respectively. Femoral component position did not change from early postoperative imaging relative to long-term follow-up at ≥5 years (P = .097). Median modified Harris Hip Scores improved from 58.3 (49.5-64.9) points preoperative to 95.7 (88.0-100) points at follow-up (P < .0001). CONCLUSIONS: The reduced distal profile stem studied showed no stem revisions at long-term follow-up with an all-cause survivorship of 97.5% at a median follow-up of 8.4 (7.0-9.3) years. The stem showed good bone integration and stability at midterm follow-up in most patients reviewed.

Evaluation of Rhizobia strains UFLA 02 100 and CIAT 899 in line LEP 02 11 of Phaseolus vulgaris L / Avaliação das estirpes de rizóbio ufla 02 100 e cia t 899 na linhagem lep 02 11 de phaseolus vulgaris l

The growing quest for sustainability in agricultural production systems has been pushing researchers to develop new technologies under different soil and climatic conditions. Based on this, and knowing the socioeconomic importance of the bean, the use of biological nitrogen fixation (BNF) is explored. Thus, the quest for quantitative knowledge of BNF at the phenological stages in a new bean line using promising and commercial strains becomes necessary. The objective of this study was to evaluate the strains UFLA 02 100 and CIAT 899 in the different phenological stages of the LEP 02 11 common bean strain using the biological nitrogen fixation. The experiment was conducted in a greenhouse on the Maringá-PR campus of the State University of Maringá. The design was a randomized complete block design in a 6x4 factorial scheme with four replications. The factor A comprised six nitrogen sources: Control, strain UFLA 02 100, strain CIAT 899, Nitrogen 60 kg ha-1, strain UFLA 02 100 + Nitrogen 30 kg ha-1, strain CIAT 899 + Nitrogen 30 kg ha-1 and the B factor is the phenological stages V4, R5, R6 and R8. The analyzed variables were: dry mass of nodules (DMN, grams/plant), dry mass of shoot (DMS, grams/plant), nitrogen content in shoot (NCS, %) and accumulation of nitrogen in shoot (ANS, grams/plant). For the statistical analysis of the data, the means test was used for the variables in the stages. The CIAT 899 strain statistically outperformed UFLA 02 100 for most variables and it was found that nitrogen fertilization negatively affected nodulation

A crescente busca pela sustentabilidade nos sistemas de produção agrícolas vem impulsionando os pesquisadores a desenvolverem novas tecnologias nas diferentes condições edafoclimáticas. Com base nisso, e sabendo da importância socioeconômica do feijoeiro, o uso da fixação biológica de nitrogênio (FBN) é explorada. Assim, a busca do conhecimento quantitativo da FBN nos estádios fenológicos em uma nova linhagem de feijão utilizando estirpes promissoras e comerciais se torna necessário. Destamaneira, o objetivo foi avaliar as estirpes UFLA 02 100 eCIAT 899nos diferentes estádios fenológicos da linhagem de feijão comum LEP 02 11 mediante o uso da fixação biológica de nitrogênio. O experimento foi conduzido em casa de vegetaçãono campus de Maringá-PR da Universidade Estadual de Maringá. O delineamento foi o de blocos ao acaso (DBC) em esquema fatorial 6x4 com quatro repetições. O fator A compreendeu seis fontes de nitrogênio: Testemunha, estirpe UFLA 02 100, estirpe CIAT 899, Nitrogênio 60 kg ha-1, estirpe UFLA 02 100+Nitrogênio 30 kg ha-1, estirpe CIAT 899+Nitrogênio 30 kg ha-1 e o fator B os estádios fenológicos V4, R5, R6 e R8. As variáveis analisadas foram: massa seca de nódulos (MSN, gramas/planta), massa seca da parte aérea (MSPA, gramas/planta), teor de nitrogênio na parte aérea (TNPA, %) e acúmulo de nitrogênio na parte aérea (ANPA, gramas/planta). Para a análise estatística dos dados utilizou-se o teste de médias para as variáveis nos estádios. A estirpe CIAT 899 superou estatisticamente a UFLA 02 100 para a maioria das variáveis e constatou-se que a adubação nitrogenada afetou negativamente a nodulação.

Biological fixation between calcium phosphate-hybridized tendon graft and tibial bone tunnel in anatomic single-bundle ACL reconstruction - A case report.

The purpose of this study was to histologically observe a specimen of a calcium phosphate (CaP)-hybridized tendon graft-bone interface at the posterior side of tibial bone tunnel obtained during the revision anterior cruciate ligament (ACL) reconstruction. We present the case of a 15-year-old female who was returning to sports 7 months and 12 days after primary anatomic single-bundle ACL reconstruction with no instability. Re-rupture was diagnosed 9 months and 12 days after the surgery. At the joint aperture site, a firm biological fixation via direct bonding area, cartilaginous tissue, and dense collagen fiber were observed without the presence of a nonbonding gap area.

Comparative Analysis of Early Follow-up of Biologic Fixation and Cemented Stem Fixation for Femoral Tumor Prosthesis.

OBJECTIVE: To compare the safety and efficacy between biologic fixation and traditional cement stems for the fixation of distal femoral prostheses for reconstruction following tumor resection. METHODS: Retrospective analysis was performed of patients who received a first distal femoral tumor prosthesis, with a rotating hinge, in the Department of Orthopaedic Oncology of Beijing Jishuitan Hospital between October 2011 and January 2016. Two hundred and sixty eligible cases were enrolled, with a cemented fixation used in 199 of these cases and a biologic fixation in 61 cases. Survival rates and survival time of prostheses were analyzed, with prosthetic failure considered as the endpoint event for survival time of the prosthesis. Kaplan-Meier survival curve and the log-rank test were used to compare survival rates between the two types of fixation methods, and factors that may affect the survival rate of prosthesis were evaluated. RESULTS: Of the 260 cases forming our study group, 138 were males and 122 females, with 102 males and 97 females in the cemented fixation group (mean age, 25.8 years; range, 8-72 years) and 36 males and 25 females in the biologic fixation group (mean age, 25.5 years; range, 12-59 years). Osteosarcoma was the most common type of tumor (188 cases, 72.3%), of which 145 cases (72.9%) were in the cemented and 45 cases (72.1%) in the biologic fixation group. Among the 260 cases enrolled into the study group, 13 patients were lost to follow-up. The average duration of follow-up for the remaining 247 cases was 28.8 months (median, 28.8 months; range, 4-61 months). The 3-year overall survival rate of prostheses was 87.2% for the biologic fixation group and 80.4% in the cemented fixation group (P = 0.389). The 3-year mechanical survival rate (excluding cases of infection and oncologic progression) was 100% for the biologic fixation and 97.6% for the cemented fixation group (P = 0.468). Complications were identified in 21 cases: 3 cases (5%) in the biologic and 18 cases (9.6%) in the cemented fixation group (P = 0.264). Two revisions were required in the cemented fixation group, but no revision was required in the biologic fixation group. A total of 10 patients required amputation after prosthesis implantation. Of these, 7 cases (4 cement and 3 biologic) were due to tumor recurrence; 3 cases were due to infection, with all cases occurring in the cement fixation group. CONCLUSION: The current study provides a baseline reference for future mid-term to long-term follow-up, laying the foundation for further studies and comparison of the incidence of aseptic loosening of both types of prosthesis.

Neither significant osteoarthritic changes nor deteriorating subjective outcomes occur after hybrid fixation of osteochondritis dissecans in the young adult.

PURPOSE: The goal of the fixation of painful osteochondritis dissecans of the femoral condyles in adults is to integrate the osteochondral fragment and thus achieve a normal hyaline cartilaginous coverage. The addition of a biological process to primary fixation may result in improved fragment integration (hybrid fixation). Osteochondral plugs may fulfil this role. The aim of this study was to evaluate long-term clinical and radiological results after hybrid fixation of unstable osteochondritis dissecans. The hypothesis was that the rate of secondary osteoarthritis would be low. METHODS: Nine patients treated by hybrid fixation were retrospectively reviewed at a median follow-up of 10.1 years (range 7-14). The median age at surgery was 21 (range 17-28). Six of them were evaluated as ICRS grade II and three, as ICRS grade III. The mean surface of the lesion was 4.5 cm2. All patients were followed up clinically (IKDC, KOOS, Lysholm) and radiologically [Kellgren-Lawrence score (KL)]. RESULTS: During arthroscopic assessment at the time of screw removal (3 months after surgery), the fragments were stable, and autograft plugs were all well integrated. At the most recent follow-up visit, the median IKDC score was 85.8 (range 51.72-100), the KOOS score was 87.7 (52.4-100), and the Lysholm scale score was 89.8 (77-100). In 7 out of 9 patients, radiographs showed a joint space KL grade of 0 or 1. CONCLUSION: Hybrid fixation for treating osteochondritis dissecans lesions of the femoral condyles using mechanical and biological fixation provides healing of the osteochondral fragments with good long-term outcomes. No significant osteoarthritic change was seen with this technique at a mid-term follow-up. LEVEL OF EVIDENCE: IV-case series.

Enhanced biological fixation of ligaments to bone tissues utilizing chitin fabrics.

In ligament reconstruction involving anterior cruciate ligament surgery, biological fixation between the transferred ligament and bone tissue is critical for achieving successful outcomes. Here, we administered chitin fabrics into the bone tunnels and evaluated their efficacy in promoting biological fixation. An animal model on the rat's patellar ligament was employed. First, bone tunnels were created in the lateral condyle of the femur. The ligament was then separated from the tibial tuberosity, and half was inserted into the tunnel and fixed with the use of end button. Animals in the experimental group were treated with microfiber nonwoven chitin fabric, whereas control animals received no treatment. Specimens were collected at 2, 4, and 6 weeks after surgery, and the fixation strength was measured by mechanical tests. Histological sections were prepared from samples prepared 4 weeks after surgery, and the diameter of bone tunnel and the width ratio of collagenous tissue in the bone tunnel were measured. Administration of chitin significantly increased the mean fixation strength at 4 and 6 weeks after surgery. Furthermore, chitin also promoted bone formation in the bone tunnel and increased the density of collagen fibers. Thus, microfiber nonwoven chitin fabric enhanced the biological fixation of the ligament to the bone tissue. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2355-2360, 2018.

Designing an Optimized Novel Femoral Stem.

BACKGROUND: After total hip arthroplasty, there would be some problems for the patients. Implant loosening is one of the significant problems which results in thigh pain and even revision surgery. Difference between Young's modulus of bone-metal is the cause of stress shielding, atrophy, and subsequent implant loosening. MATERIALS AND METHODS: In this paper, femoral stem stiffness is reduced by novel biomechanical and biomaterial design which includes using proper design parameters, coating it with porous surface, and modeling the sketch by the software. Parametric design of femoral stem is done on the basis of clinical reports. RESULTS: Optimized model for femoral stem is proposed. Curved tapered stem with trapezoidal cross-section and particular neck and offset is designed. Fully porous surface is suggested. Moreover, Designed femoral stem analysis showed the Ti6Al4V stem which is covered with layer of 1.5 mm in thickness and 50% of porosity is as stiff as 77 GPa that is 30% less than the stem without any porosity. Porous surface of designed stem makes it fix biologically; thus, prosthesis loosening probability decreases. CONCLUSION: By optimizing femoral stem geometry (size and shape) and also making a porous surface, which had an intermediate stiffness of bone and implant, a more efficient hip joint prosthesis with more durability fixation was achieved due to better stress transmission from implant to the bone.

Acetabular revisions using porous tantalum components: A retrospective study with 5-10 years follow-up.

AIM: To evaluate the clinical and X-ray results of acetabular components and tantalum augments in prosthetic hip revisions. METHODS: Fifty-eight hip prostheses with primary failure of the acetabular component were reviewed with tantalum implants. The clinical records and X-rays of these cases were retrospectively reviewed. Bone defect evaluations were based on preoperative CT scans and classified according to Paprosky criteria of Radiolucent lines and periprosthetic gaps; implant mobilization and osteolysis were evaluated by X-ray. An ad hoc database was created and statistical analyses were performed with SPSS software (IBM SPSS Statistics for Windows, version 23.0). Statistical analyses were carried out using the Student's t test for independent and paired samples. A P value of < 0.05 was considered statistically significant and cumulative survival was calculated by the Kaplan-Meier method. RESULTS: The mean follow-up was 87.6 ± 25.6 mo (range 3-120 mo). 25 cases (43.1%) were classified as minor defects, and 33 cases (56.9%) as major defects. The preoperative HHS rating improved significantly from a mean of 40.7 ± 6.1 (range: 29-53) before revision, to a mean of 85.8 ± 6.1 (range: 70-94) at the end of the follow-up (Student's t test for paired samples: P < 0.001). Considering HHS only at the end of follow-up, no statistically significant difference was observed between patients with a major or minor defect (Student's t test for independent samples: P > 0.05). Radiolucent lines were found in 4 implants (6.9%). Postoperative acetabular gaps were observed in 5 hips (8.6%). No signs of implant mobilization or areas of periprosthetic osteolysis were found in the x-rays at the final follow-up. Only 3 implants failed: 1 case of infection and 2 cases of instability. Defined as the end-point, cumulative survival at 10 years was 95% (for all reasons) and 100% for aseptic loosening of the acetabular component. CONCLUSION: The medium-term use of prosthetic tantalum components in prosthetic hip revisions is safe and effective in a wide variety of acetabular bone defects.