Mechanochemically assisted morphing of shape shifting polymers.

Morphing in creatures has inspired various synthetic polymer materials that are capable of shape shifting. The morphing of polymers generally relies on stimuli-active (typically heat and light active) units that fix the shape after a mechanical load-based shape programming. Herein, we report a strategy that uses a mechanochemically active 2,2'-bis(2-phenylindan-1,3-dione) (BPID) mechanophore as a switching unit for mechanochemical morphing. The mechanical load on the polymer triggers the dissociation of the BPID moiety into stable 2-phenylindan-1,3-dione (PID) radicals, whose subsequent spontaneous dimerization regenerates BPID and fixes the temporary shapes that can be effectively recovered to the permanent shapes by heating. A greater extent of BPID activation, through a higher BPID content or mechanical load, leads to higher mechanochemical shape fixity. By contrast, a relatively mechanochemically less active hexaarylbiimidazole (HABI) mechanophore shows a lower fixing efficiency when subjected to the same programing conditions. Another control system without a mechanophore shows a low fixing efficiency comparable to the HABI system. Additionally, the introduction of the BPID moiety also manifests remarkable mechanochromic behavior during the shape programing process, offering a visualizable indicator for the pre-evaluation of morphing efficiency. Unlike conventional mechanical mechanisms that simultaneously induce morphing, such as strain-induced plastic deformation or crystallization, our mechanochemical method allows for shape programming after the mechanical treatment. Our concept has potential for the design of mechanochemically programmable and mechanoresponsive shape shifting polymers.

Late Presentation of Giant Osteochondroma of Talar Neck in Elderly: A Case Report and Review of Literature.

Introduction: Osteochondroma is a benign bone tumor of the bone primarily seen in younger age groups. However, late presentation of the same is a rare incidence, as the symptoms develop rapidly due to compression of nearby structures. Case Report: We present a case of a 55-year-old male patient with a giant osteochondroma originating from the neck of the talus. The patient presented with a huge 100 × 70 × 50 mm swelling over the ankle. The patient underwent an excision of the swelling. Histopathological examination of the swelling confirmed the findings of an osteochondroma. The patient had an uneventful recovery after the excision and resumed his functional activity completely. Conclusion: Giant osteochondroma around the ankle is an extremely rare entity. Even rarer is a late presentation in the 6th decade onward. However, the management like others involves the excision of the lesion.

Knee Implant Identification by Fine-Tuning Deep Learning Models.

BACKGROUND: Identification of implant model from primary knee arthroplasty in pre-op planning of revision surgery is a challenging task with added delay. The direct impact of this inability to identify the implants in time leads to the increase in complexity in surgery. Deep learning in the medical field for diagnosis has shown promising results in getting better with every iteration. This study aims to find an optimal solution for the problem of identification of make and model of knee arthroplasty prosthesis using automated deep learning models. METHODS: Deep learning algorithms were used to classify knee arthroplasty implant models. The training, validation and test comprised of 1078 radiographs with a total of 6 knee arthroplasty implant models with anterior-posterior (AP) and lateral views. The performance of the model was calculated using accuracy, sensitivity, and area under the receiver-operating characteristic curve (AUC), which were compared against multiple models trained for comparative in-depth analysis with saliency maps for visualization. RESULTS: After training for a total of 30 epochs on all 6 models, the model performing the best obtained an accuracy of 96.38%, the sensitivity of 97.2% and AUC of 0.985 on an external testing dataset consisting of 162 radiographs. The best performing model correctly and uniquely identified the implants which could be visualized using saliency maps. CONCLUSION: Deep learning models can be used to differentiate between 6 knee arthroplasty implant models. Saliency maps give us a better understanding of which regions the model is focusing on while predicting the results.

Epidemiology of Revision Total Hip Arthroplasty: An Indian Experience.

BACKGROUND: With increasing numbers of primary total hip replacement (THR), there has been a substantial increase in revision total hip replacement (RTHR) surgeries. RTHR are complex joint reconstruction surgeries involving significant cost, expertise and infrastructure. With its significant socioeconomic impact, we need to keep a close watch on the epidemiological trends of these procedures. METHODS: We prospectively studied the first-time RTHR performed at our institution for a 7-year period (2011-2017). We looked at patient demographics, the workload of RTHR and its etiology. We reviewed the microbiological profiles of septic revisions. RESULTS: Of the 1244 THR procedures performed, 260 (21%) were first-time revisions. The predominant cause of revisions was a prosthetic infection (38%) followed by aseptic loosening (33%), instability (15%), peri-prosthetic fracture (11%) and implant breakage (3%). In the aseptic loosening group, 55% of cases had primary cemented implant, 44% had only stem loosening, 31% had cup loosening and 25% had both cup and stem loosening. In the early, midterm, and late-failure groups, prosthetic infection remained the main cause of failure. In 60% of the septic revisions, the offending organisms could not be identified and of those identified most (77%) were gram negative. CONCLUSION: In our study, the RTHR burden was 21%, which is similar to historic revision data from the west (1998-2001) and twice as compared to recent trends from the west (9-11%). Unlike western data, which show aseptic loosening (30-60%) as the predominant cause of hip revisions, in our study infection was the number one cause (38%).

Early Outcomes of Medial Pivot Total Knee Arthroplasty Compared to Posterior-Stabilized Design: A Randomized Controlled Trial.

BACKGROUD: The indications for total knee arthroplasty (TKA) have been expanded to include younger, demanding patients. Some TKA patients expect a return to high-performance activities to restore optimum quality of life. The concept of the medial pivot (MP) TKA is that more natural knee kinematics can be achieved by altering the bearing design. In the present study, we compared the early outcomes of MP TKA with posterior-stabilized (PS) TKA in terms of patient-reported outcomes, function, and performance. METHODS: This randomized study was performed in a high volume joint replacement facility of a tertiary care military hospital. We enrolled 40 patients each in the MP group and PS group and assessed knee flexion, patient-reported outcome (new Knee Society Score [new KSS]), patient performance (Delaware Osteoarthritis Profile Score [DOPS]), and function (Forgotten Joint Score [FJS]) at 2 years after surgery. RESULTS: Compared to PS group patients, MP group patients had similar patient-reported outcomes assessed by new KSS (satisfaction, expectation, and activity scales) and FJS. MP knee patients had better performance in the timed up and go test (p < 0.026) and self-paced walk test (p < 0.002) of DOPS. The gain in knee flexion (9.3° ± 14°) compared to baseline was significantly greater in the PS group (p < 0.013). CONCLUSIONS: When assessed by DOPS, getting up from chair and walking speed were significantly better in MP knee patients than in PS knee patients. However, considering the predictable rollback ensured by cam and post, the PS knee produced better knee flexion. Despite these results, patients were equally satisfied with the two designs.

Synovial Fluid Cell Proteomic Analysis Identifies Upregulation of Alpha-Taxilin Proteins in Rheumatoid Arthritis: A Potential Prognostic Marker.

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease affecting the joints and surrounding tissue. Identification of novel proteins associated with the progression of a disease is a prerequisite for understanding the pathogenesis of RA. The present study was undertaken to identify the potential biomarkers from a less explored biological sample such as synovial fluid (SF) cells which is specific for RA and to analyze their functional aspects using proteomic approach. Two-dimensional gel electrophoresis (2-DE) was performed using synovial fluid cells of RA and osteoarthritis (OA) patients, and 7 differentially expressed proteins were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS/MS). Αlpha-Taxilin (α-Taxilin) has been found as one of the novel, significantly up regulated protein in RA. It has been validated in the synovium, synovial fluid (SF), SF cells, and plasma samples by Western blot, enzyme-linked immunosorbent assay (ELISA), fluorescence-activated cell sorting (FACS), immunohistochemistry (IHC), and real-time PCR. The identification of autoantibody against α-Taxilin and in silico studies has further helped us to understand its involvement in disease mechanism. The present study will therefore provide knowledge towards the etiology of RA that pave the way for suitable prognostic marker identification along with other clinical parameters.

Evaluation of Anti-inflammatory Effects of Choerospondias axillaris Fruit's Methanolic Extract in Synoviocytes and CIA Rat Model.

BACKGROUND: Rheumatoid Arthritis (RA) is an autoimmune, systemic disease mainly affecting joints. Presently, there is no specific treatment/ drug available for curing RA except few supportive medicines. Therefore, the focus has been shifted to medicinal plants for the treatment of such diseases. Choerospondias axillaris commonly known as Lupsi/Lapsi and has been reported to have several properties for the treatment of various diseases. OBJECTIVE: The present study has been conducted to explore the anti-inflammatory effects of Choerospondias axillaris fruit extract on Synoviocytes (FLS) and Collagen-Induced Arthritis (CIA) rat model. METHODS: Methanolic extract of the Choerospondias axillaris fruit was used for determining phytochemical, antioxidant and anti-inflammatory properties. Antioxidant activity of Choerospondias axillaris fruit was determined by free radicals scavenging assays and bioactive compounds were identified via LC-MS/MS analysis. Anti-inflammatory effect was investigated in RA and Osteo Arthritis (OA) primary cells and also in Collagen Induced Arthritis (CIA) rat models. Further, the medicinal properties of anti-inflammatory bioactive compounds were supported by docking studies. RESULTS: In-vitro and in-vivo studies showed significant decrease in the levels of inflammatory cytokines. Docking analysis revealed that quercetin inhibits TNF-α having -9.1 kcal/mol binding energy and 10.13 µM inhibitory constant. Quercetin also inhibits IL-6 having -6.6 kcal/mol binding energy and 21.9 µM inhibitory constant. CONCLUSION: Observed results suggest that the underutilized fruit Choerospondias axillaris can be used to reduce the inflammation of inflammatory diseases like RA.

Epidemiology of Revision Total Knee Arthroplasty: A Single Center's Experience.

BACKGROUND: There has been a gradual increase in the revision TKA (RTKA) workload due to expanding indications of total knee arthroplasty (TKA), coupled with improving patient longevity. Western countries are already looking at their data on RTKA to plan for the future heath care needs of these patients. Limited data is available on RTKA from developing countries. Our study attempts to fill this gap in knowledge. MATERIALS AND METHODS: We prospectively documented details of all RTKA performed at our centre for a period of six years (2011-16). We recorded the volume, causes and time to failure from index surgery of all RTKA and further recorded microbiological pattern in septic failures. We looked at the proportion of each cause of failure and time from index surgery. RESULTS: Of the 5068 TKA procedures performed from January 2011 to December 2016, 201 (4%) were first-time revisions. The predominant cause of revisions was prosthetic infection (61%) followed by aseptic loosening (18%) and instability (7%). In the early, mid term, and late-failure groups, prosthetic infection remained the main cause of failure. In 47% of the septic revisions, the offending organisms could be identified and of those identified most (67%) were Gram-negative. CONCLUSION: The volume of first-time RTKA procedures (4%) at our center remained low compared with that of the Western countries. In Western countries, the incidence of late aseptic failures was higher than that of early-septic failures, whereas in our study, revisions were more commonly performed in the early-failure group (48%) and most failures were due to prosthetic infection (61%).

Ninety-Day Morbidity and Mortality in Risk-Screened and Optimized Patients Undergoing Two-Team Fast-Track Simultaneous Bilateral TKA Compared With Unilateral TKA-A Prospective Study.

BACKGROUND: Simultaneous bilateral total knee arthroplasty (SBTKA) offers significant socioeconomic benefits. However, retrospective studies and public health data show increased mortality and morbidity rates in patients undergoing SBTKA compared with those undergoing unilateral TKA (UTKA), and there have been recommendations against the use of SBTKA. High-volume centers, which feature careful patient selection and fast-tracked surgery, continue to perform SBTKA and have published their results in favor of the procedure. However, the quality of evidence remains poor. METHODS: We prospectively examined 90-day morbidity and mortality of SBTKA compared with UTKA in risk-screened and optimized patients in our high-volume joint replacement facility. A total of 1200 consecutive patients were recruited in each arm. RESULTS: Ninety-day mortality was higher in SBTKA patients than in UTKA patients (0.58% vs 0.42%, respectively; P = .5646). Overall procedure-related complications were significantly higher in the SBTKA group (7.25% vs 4.42%, respectively; P = .0034). The relative risk of cardiovascular complications in SBTKA patients was 6.5 times higher than that in UTKA patients (1.08% vs 0.17%, respectively; P = .0136). Neurological complications were 9.5 times more common in the SBTKA group (1.58% vs 0.17%, respectively; P = .0024). All other complications were comparable in the 2 groups. CONCLUSION: Risk screening and preoperative optimization reduce mortality and overall complication rates in SBTKA patients; however, overall procedure-related complications, specifically cardiovascular and neurological, remain significantly high in SBTKA patients, for which a guarded approach is recommended.

Outcome of Unicondylar Knee Arthroplasty vs Total Knee Arthroplasty for Early Medial Compartment Arthritis: A Randomized Study.

BACKGROUND: With increasing number of patients with early osteoarthritis of knee opting for total knee arthroplasty (TKA), there has been increase in patients dissatisfied with surgical outcomes. It is being presumed that offering unicondylar knee arthroplasty (UKA) to them would improve outcomes. METHODS: Primary objective of our study was to look for any difference in patient-reported outcome and function at 2-year follow-up in patients undergoing UKA as compared to TKA. Our study was a randomized study with parallel assignment conducted at a high-volume specialized arthroplasty center. Eighty patients with bilateral isolated medial compartment knee arthritis were randomized into simultaneous 2-team bilateral TKA (n = 40) and UKA (n = 40) group. We finally analyzed 36 patients in each group. Main outcome measure was improvement in Knee Outcome Survey-Activities of Daily Living Scale (KOS-ADLS) and High Activity Arthroplasty Score (HAAS) obtained at 2-year follow-up. RESULTS: Improvement in KOS-ADLS and HAAS at 2 years was similar (P = .2143 and .2010) in both groups. Performance as assessed with Delaware index was also similar. Length of hospital stay was less in UKA group (6.6 days as against 5.4 days). Complications and readmission rates were more in TKA group (nil in UKA group; 08 in TKA group). CONCLUSION: At 2-year follow-up, UKA provides similar improvement in patient-reported outcomes, function, and performance as compared to TKA when performed in patients with early arthritis. However, UKA patients have shorter hospital stay and fewer complications.

A multi-responsive turn-on flurogenic probe to sense Zn(2+), Cd(2+) and Pb(2+): left-right-center emission signal swing.

A versatile new fluorogenic Schiff base probe (L) has been synthesized by the reaction of quinoline-2-carbohydrazide (which acts as the chelating site) and 4-dimethylamino cinnamaldehyde (which acts as the signaling unit). L can sense three of the most biologically and environmentally important metal ions, Zn(2+), Cd(2+) and Pb(2+), among various tested metal ions through selective TURN-ON fluorescence responses in physiological pH. Interestingly, L can not only sense Zn(2+), Cd(2+) and Pb(2+) fluorometrically in physiological conditions but can also distinguish one from another by exhibiting individual intrinsic left-right-center TURN-ON emission signal swings. These selective fluorescence responses were explained by a chelation-enhanced fluorescence (CHEF) mechanism. Theoretical calculations were carried out to ascertain the preferred L-metal ion binding mode.

A near-infrared emissive Al(3+) sensing platform for specific detection in solution, cells and probing DNase activity.

A new tricarbocyanine-based chemosensor exhibited a dramatic Al(3+)-specific fluorescence turn-on response in the near-infrared (NIR) region. The receptor was found to be highly selective towards Al(3+) over other metal ions in physiological condition. The sensor was non-toxic and could thus be employed as an imaging probe for detecting intracellular Al(3+) in live cells. Interestingly, upon interaction with DNA in solution, the L-Al(3+) ensemble rendered tracking of DNase activity in solution through a systematic reduction in the fluorescence emission intensity.

A sole multi-analyte receptor responds with three distinct fluorescence signals: traffic signal like sensing of Al(3+), Zn(2+) and F(-).

A dialdehyde-based multi-analyte sensor renders distinctive emission spectra for Al(3+), Zn(2+) and F(-) ions. The ligand exhibited different types of interactions with these three different ions resulting in the enhancement of fluorescence intensity at three different wavelengths. All the sensing processes were studied in detail by absorption spectroscopy, emission spectroscopy and (1)H-NMR titration experiment. The ligand has the working ability in a wide pH range including the physiological pH. The ligand is non-toxic and amicable for sensing intracellular Al(3+) and Zn(2+) in live HeLa cells.

Bearing surfaces in hip replacement - Evolution and likely future.

Total hip arthroplasty has evolved from the first total hip arthroplasty in 1938, through the revolutionization of hip arthroplasty by principles of low friction arthroplasty introduced by Sir John Charnley in 1960s to the present state of the art implants and techniques. The main concern regarding failure of total hip arthroplasty has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. Therefore, recent research has been focussing on alternative bearing surfaces to reduce the particulate debris generated. These bearing surfaces include ceramic-polyethylene, metal-metal as well as ceramic-ceramic articulations and have demonstrated lesser friction rates as well as significantly lower wear rates as compared to widely used metal on polyethylene surfaces. Clinical experience until now has shown that metal on metal articulations have significant safety concerns whereas metal-on-highly crosslinked polyethylene, ceramic on ceramic and ceramic on highly crosslinked polyethylene articulations have shown encouraging results to hold promise for wider use in younger and more active patients. This review article discusses positives and drawbacks of various bearing surfaces in current clinical use in total hip arthroplasty as well as briefly explores the newer technologies on the horizon which may even further decrease wear and improve total hip arthroplasty survivorship.

A novel chemosensor with visible light excitability for sensing Zn2+ in physiological medium and in HeLa cells.

In the present study a novel imine-hydrazone based fluorescent chemosensor () for efficient and selective sensing of Zn(2+) over other biologically important metal ions under physiological conditions is reported. An enhancement in fluorescence emission intensity of the developed probe with a red shift of ∼25 nm was observed for Zn(2+), whereas other metal ions failed to reveal any significant change in the emission spectra. Interestingly, the receptor functioned under completely physiological conditions (99.7% HEPES buffer) and has visible light excitability. Sensing of Zn(2+) was investigated in detail by absorption spectroscopy, emission spectroscopy, DFT calculation, (1)H-NMR titration experiment and ESI-MS experiment. The association constant between and Zn(2+) was found to be 5.58 × 10(5) M(-1). The receptor could detect as low as 69 ppb Zn(2+). Sensing of Zn(2+) is proposed through switch-on of intramolecular charge transfer (ICT) and chelation enhanced fluorescence (CHEF) processes after the introduction of Zn(2+) into the free ligand. The developed receptor was non-toxic and rendered intracellular sensing of Zn(2+) in HeLa cells through fluorescence imaging studies.

Comparison of peripheral nerve stimulator versus ultrasonography guided axillary block using multiple injection technique.

BACKGROUND: The established methods of nerve location were based on either proper motor response on nerve stimulation (NS) or ultrasound guidance. In this prospective, randomised, observer-blinded study, we compared ultrasound guidance with NS for axillary brachial plexus block using 0.5% bupivacaine with the multiple injection techniques. METHODS: A total of 120 patients receiving axillary brachial plexus block with 0.5% bupivacaine, using a multiple injection technique, were randomly allocated to receive either NS (group NS, n = 60), or ultrasound guidance (group US, n = 60) for nerve location. A blinded observer recorded the onset of sensory and motor blocks, skin punctures, needle redirections, procedure-related pain and patient satisfaction. RESULTS: The median (range) number of skin punctures were 2 (2-4) in group US and 3 (2-5) in group NS (P < 0.001). No differences were observed in the onset of sensory block in group NS (6.17 ± 1.22 min) and in group US (6.33 ± 0.48 min) (P = 0.16), and in onset of motor block (23.33 ± 1.26 min) in group US and (23.17 ± 1.79 min) in group NS; P > =0.27). Insufficient block was observed in three patient (5%) of group US and four patients (6.67%) of group NS (P > =0.35). Patient acceptance was similarly good in the two groups. CONCLUSION: Multiple injection axillary blocks with ultrasound guidance provided similar success rates and comparable incidence of complications as compared with NS guidance with 20 ml 0.5% bupivacaine.

Zn2+ and pyrophosphate sensing: selective detection in physiological conditions and application in DNA-based estimation of bacterial cell numbers.

A diformyl-quinoline based receptor (L1) exhibits selective colorimetric and fluorometric sensing of Zn(2+) in aqueous medium at pH 7.4 based on the intraligand charge transfer (ICT) process. The in situ formed phenoxo-bridged complex, L1·2Zn can selectively and specifically sense PPi among all the other biologically important anions including ATP through reversible binding. The detection limit for Zn(2+) and PPi were found to be approximately 56 and 2 ppb, respectively. The unique selectivity of the PPi by the L1-Zn ensemble could be used as an analytical tool to probe PPi generation in a prototype polymerase chain reaction (PCR) setup and track DNA amplification with higher sensitivity as compared to conventional agarose gel electrophoresis. Interestingly, the principle of PPi estimation in PCR rendered rapid estimation of bacterial cell numbers with a limit of detection of 10 CFU of Escherichia coli MTCC 433 in as early as 10 PCR cycles. The proposed method of PPi sensing offers interesting application potential in PCR-based rapid diagnostics for pathogenic agents and microbiological quality control.

Addition of ketamine or dexmedetomidine to lignocaine in intravenous regional anesthesia: A randomized controlled study.

INTRODUCTION: Ketamine and dexmedetomidine decrease anesthetic requirement and provide analgesia to patients. We designed this study to compare the effect of dexmedetomidine and ketamine when added to lignocaine in intravenous regional anesthesia (IVRA). MATERIALS AND METHODS: Seventy two patients undergoing hand surgery were randomly assigned to three groups to receive IVRA. They received 20 ml of 1% lignocaine and either 1 ml of isotonic saline (Group L, n = 24); or 0.5 mg/kg body weight ketamine (Group LK, n = 24) or 1 mcg/kg body weight dexmedetomidine (Group LD, n = 24). Sensory and motor block onset and recovery time were noted. After the tourniquet deflation, pain and sedation values, time to first analgesic requirement and any side effects were noted. RESULTS: Shortened sensory and motor block onset times (69.17 min and 7.83 min respectively, P < 0.0001) and improved quality of anesthesia (satisfaction score = 3, P < 0.05) were found in ketamine group. Visual analog scale scores (3.21 ± 0.41) were comparable while time to first analgesic requirement (166.25 ± 25.89 min, P < 0.0001) was significantly longer in dexmedetomidine group after tourniquet release. CONCLUSION: We conclude that the addition of 1 mcg/kg of body weight dexmedetomidine or 0.5 mg/kg of body weight ketamine to lignocaine for IVRA improves quality of anesthesia and perioperative analgesia without causing side effects. We considered ketamine reduced the time for onset of block, delayed the onset of tourniquet pain, and reduced postoperative analgesic requirement and had a better patient satisfaction than placebo or dexmedetomidine.

Mechanical properties of reconstructed achilles tendon with transfer of peroneus brevis or flexor hallucis longus tendon.

Treatment of chronic Achilles tendon ruptures can be technically difficult because of tendon retraction, atrophy, and short distal stumps. Surgical repair of chronic Achilles tendon ruptures focuses on local and free tendon transfers, as well as reconstruction with allografts or synthetic materials. This study examined the in vitro mechanical properties of a reconstructed Achilles tendon with the peroneus brevis or the flexor hallucis longus tendons in a human cadaver model. The tendons were harvested from 17 fresh-frozen human cadavers, and the same techniques were used for all of the model reconstructions. Biomechanical measurements included the failure load, stiffness, energy-to-peak load, and mode of failure. The mean failure load was significantly higher in the peroneus brevis group (P = .036), and there was no significant difference in stiffness and energy-to-peak load between the peroneus brevis and flexor hallucis longus groups. In every case, the mode of failure involved the tendon graft pulling through either the distal or proximal stump of the Achilles tendon. The greater failure loads observed with the use of peroneus brevis may not be clinically relevant, however, because of the magnitude of the peak loads observed in the cadaveric model. The present study supports the use of either peroneus brevis or flexor hallucis longus for reconstruction of chronic Achilles tendon ruptures and indicates the need for surgeons to carefully reinforce the attachment of the transferred tendon grafts to the stumps of the Achilles tendon to prevent pullout.