Anterior Spike Research Articles

An Anterior Spike Decreases Bone-Implant Micromotion in Cementless Tibial Baseplates for Total Knee Arthroplasty: A Biomechanical Study

BackgroundCementless tibial baseplates in total knee arthroplasty include fixation features (eg, pegs, spikes, and keels) to ensure sufficient primary bone-implant stability. While the design of these features plays a fundamental role in biologic fixation, the effectiveness of anterior spikes in reducing bone-implant micromotion remains unclear. Therefore, we asked: Can an anterior spike reduce the bone-implant micromotion of cementless tibial implants? MethodsWe performed computational finite element analyses on 13 tibiae using the computed tomography scans of patients scheduled for primary total knee arthroplasty. The tibiae were virtually implanted with a cementless tibial baseplate with 2 designs of fixation of the baseplate: 2 pegs and 2 pegs with an anterior spike. We compared the bone-implant micromotion under the most demanding loads from stair ascent between both designs. ResultsBoth fixation designs had peak micromotion at the anterior-lateral edge of the baseplate. The design with 2 pegs and an anterior spike had up to 15% lower peak micromotion and up to 14% more baseplate area with micromotions below the most conservative threshold for ingrowth, 20 μm, than the design with only 2 pegs. The greatest benefit of adding an anterior spike occurred for subjects who had the smallest area of tibial bone below the 20 μm threshold (ie, most at risk for failure to achieve bone ingrowth). ConclusionsAn anteriorly placed spike for cementless tibial baseplates with 2 pegs can help decrease the bone-implant micromotion during stair ascent, especially for subjects with increased bone-implant micromotion and risk for bone ingrowth failure.

Factors associated with conversion to open reduction of type 3 supracondylar humerus fractures in children

BackgroundThe US News and World report utilizes the number of supracondylar humerus fractures treated in an open procedure, excluding open fractures and vascular exploration, as a metric in assessing Pediatric Orthopedic trauma care. The purpose of this study was to identify factors that increase the likelihood of a patient needing open reduction for Gartland Type 3 SCH fractures. MethodsAll pediatric patients who underwent surgical management of closed, Type 3 SCH fractures at our Pediatric Level 1 Trauma Center between 2011 and 2017 were considered for inclusion. Patient age greater than 16 years, patients with closed physes and open fractures were excluded. Electronic medical records and radiographic imaging were reviewed. Student's t- and chi-squared tests were used, and logistic regression was performed comparing closed v open reduction. Results362 subjects were included in this study. 318/362 (87.8%) were treated with closed reduction. 44/362 (12.2%) required open reduction. There were no statistically significant differences in age, gender, BMI, concomitant ipsilateral extremity fractures, Type 4 unstable fracture or patients that underwent hospital transfer. The mechanisms of injury with the greatest percentage requiring open reduction were fall from furniture and trampoline. Of those patients that underwent open reduction, 65.9% had posterolateral displacement of the fracture. Those with displacement >4 mm had 3.14 higher odds of requiring an open reduction (p = 0.002). The anterior spike fracture pattern had the highest rate of failed closed reduction of 66.7%. Of those patients that had an open reduction, 13/44 (29.5%) had a neuropraxia and 5/44 (11.4%) had vascular compromise. Those with neuropraxia had 3.26 higher odds of requiring an open reduction (p = 0.005). Time to operating room was significantly shorter in patients that underwent open reduction (p < 0.001). ConclusionOur rate of open reduction for Type 3 SCH fractures, 12.2%, is consistent with previously described rates. Posterolateral displacement of fractures, displacement >4 mm, fractures with an anterior spike and fractures associated with neurovascular compromise are more likely to undergo open reduction. Transfer status, BMI and patient age were not associated with open reduction. Open reduction was associated with shorter time to the operating room, likely representing the urgent care of significantly displaced fractures associated with neurovascular compromise. Level of evidenceLevel III.

The Reverse Oblique Supracondylar Humerus Fracture: Description of a Novel Fracture Pattern.

Sagittal profile descriptions of supracondylar humerus fractures are limited. We describe a reverse oblique (RO) pattern in which the distal fragment has a prominent anterior spike that is displaced posterior to the proximal fragment. This pattern presents a challenge during closed manipulation utilizing traditional reduction maneuvers. The purpose of this study is to compare the clinical and radiographic characteristics of the RO and non-RO patterns of supracondylar humerus fractures. We hypothesized that the RO pattern would be associated with greater soft tissue trauma. Retrospective evaluation of operative supracondylar humerus fractures treated at a tertiary pediatric hospital from 2014 to 2016. Patients were categorized into RO and non-RO groups for analysis. Associated neurovascular injuries were compared between groups. Two hundred ninety-nine consecutive patients were reviewed. The RO fracture pattern was seen in 12 patients. All displaced RO fractures were able to be closed reduced with a modification to the traditional reduction sequence. Overall cohort rates of preoperative soft tissue injury included antecubital ecchymosis 16.8%, nerve palsies 15%, and vascular compromise 6.4%. Compared with non-RO fractures, the RO fracture group had significantly higher rates of anterior interosseous nerve (AIN) palsies (P=0.013), antecubital ecchymosis (P=0.018), and compartment syndrome (P=0.043). When comparing RO with non-RO type II fractures, there were no differences in soft tissue injury (P=0.439). Compared with non-RO type III fractures, RO type III fractures had higher rates of AIN injury (P=0.047), antecubital ecchymosis (P=0.007), and overall soft tissue injury (P=0.009). This study introduces a previously undescribed supracondylar humerus fracture subtype: the RO fracture. We found increased rates of soft tissue compromise including antecubital ecchymosis and AIN palsy in this fracture type. Further, traditional reduction methods proved to be ineffectual for this fracture pattern. We utilized a simple modification that allowed for closed reduction and percutaneous pinning of displaced RO fractures. Level III-prognostic.

A morphological study of the male reproductive tract, post-testicular acrosome maturation and spermatophore formation in the black tiger prawn (Penaeus monodon).

Inferior larval production rates of domesticated Penaeus monodon broodstock has been a major hurdle to the expansion of its aquaculture, so that a better understanding of basic male reproductive biology is critical to improve the reproductive performance of this commercially important penaeid species. Following our previous study of spermatogenesis in the species, this study explored the mechanism of spermatophore formation with regards to the contribution of the reproductive tract epithelium by light and transmission electron microscopy. Four types of epithelial secretions (S1-4) were observed contributing to the three layers of the spermatophore. The primary layer of spermatophore was composed of S1 and S2, which were released from the secretory epithelial cells of the proximal vas deferens (PVD) and the secretory epithelial cells of the sperm-bearing lumen of the mid vas deferens, respectively. The secondary layer of the spermatophore was composed of S3, the secretory product of epithelial cells in the accessory tubule lumen of the mid vas deferens. The outer layer of the spermatophore was formed from S4 which was secreted by the epithelial cells in the posterior mid vas deferens and the terminal ampulla. Unique folds of the vas deferens epithelium appeared to play an important role in the formation of the spermatophore, particularly in the formation of the laminated structure of the spermatophore appendage. With respect to acrosome maturation along the reproductive tract, most spermatozoa did not have a fully developed anterior spike and a subacrosomal region when in the PVD, whereas both structures were fully formed by the time the spermatozoa reached the mid vas deferens and increased electron density when in the terminal ampulla; this observation represents the first morphological evidence of post-testicular acrosome maturation in this taxon.

Functional morphology of the male reproductive system of the white shrimp Litopenaeus schmitti (Burkenroad, 1936) (Crustacea, Penaeidea) compared to other Litopenaeus

The male reproductive system of L. schmitti is described, including spermatozoon ultrastructure. The testis is composed of 8 to 14 lobules arranged as seminiferous tubules. The proximal vas deferens is short and filled with spermatozoa without spikes. The median vas deferens is larger than the other parts of the vas deferens and it shows two ducts separated by typhlosoles, the sperm and accessory ducts. The former is filled with sperm masses, while the accessory duct shows only secretions that are part of the spermatophore material. In this region, the spermatozoa have a spike, indicating the end of the spermatogenesis. The distal vas deferens is a short tube ending in the ampulla, composed of three parts. The spermatozoa have a round main body and an anterior spike associated with the acrosomal cap. The subacrosomal space has a centrosome-like structure above the nucleus. The features of the male reproductive system of L. schmitti share the pattern of penaeoidean shrimps with closed thelyca related to the median vas deferens and the ampulla. All the differences in spermatozoon morphology and vasa deferentia are discussed, and compared to other Litopenaeus species.

The significance of the analysis on scalographic pattern for detecting malfunctioning bileaflet valve with the wavelet analysis.

The authors developed the wavelet analysis system which can detect the splitting of bileaflet mechanical heart valve (BLV) into two spikes on the scalogram, and reported that either consecutive single spike or the split behavior can detect malfunctioning BLV (MBV). The latest study on 12 BLVs suggested that the comparison between two spike areas showed higher potential to detect MBV than the split behavior. The aim of the current study is to review 226 files of BLV sound and to select the suitable scalographic property to differentiate the function of BLV with the split. Eight of 30 MBV files showed consecutive single spike, and the rest of 22 MBV files showed two spikes. Two spike areas can be compared by the following three ratios; the anterior spike area/posterior spike area (Aa/La), its reverse ratio (Pa/Aa) and the smaller spike area/the larger spike ratio (Sa/La). Therefore, the current study compared those three ratios to pursue the suitable ratio to compare two spike areas and its sensitivity to differentiate valve function by the ROC analysis. As a result, the Sa/La was suitable for comparing two spike areas, and only this ratio showed high accuracy to differentiate the function of BVL with the split, and its cutoff value was <0.665. Conclusively, the key for detecting MBV was either consecutive single spike or the mean of Sa/La<0.665. However, this cutoff point is still tentative due to small number of malfunctioning valves, and other key might be available in future.

Enhancement of trypsin-like enzymes by A23187 ionophore is crucial for sperm penetration through the egg vestment of the giant freshwater prawn.

We report the presence of trypsin-like enzymes preferring Boc-QAR-MCA substrate in sperm collected from different portions of male reproductive tracts of the giant freshwater prawn, Macrobrachium rosenbergii and compare enzyme activities before and after an A23187 calcium ionophore treatment. Fluorogenic enzyme assays revealed that testicular sperm lysates showed high trypsin-like enzyme activity but the activity was relatively low in vas deferens sperm lysates as well as in the live sperm. Upon sperm treatment with A23187, trypsin-like activity was greatly enhanced in distal vas deferens sperm. Substrate- and inhibitor-based localization studies indicated that the sperm trypsin-like enzymes were not of a soluble type but were rather of a membrane-borne type, localized at the anterior spike and upper part of the main body. Notable structural changes were also evident in A23187-induced sperm including extensive ruffling of the sperm membrane structure at the base of the main body thereby supporting the acrosome reaction response in this species. We further proved by substrate inhibition assays that the enhanced trypsin-like enzyme activity participates in sperm penetration through the vitelline envelope, a novel sperm-egg penetration mechanism that is unique in this species.

Comparison of two spike areas in bileaflet mechanical valve closing sound

We previously reported our development of a wavelet analysis system which demonstrates that in vivo bileaflet mechanical valve sound splits into two spikes at higher frequency levels and, based on this system, proposed criteria for detecting malfunctioning bileaflet valves (MBVs). However, the results of that study were only tentative due to the small number of patients with MBVs enrolled in the study. Here, we discuss the possibility of new criteria based on the scalographic properties of two spikes of bileaflet valve sound. The study cohort comprised 12 patients who each received a Carbomedics valve. Based on cinefluoroscopy findings, seven valves were classified into a "normal" group, and the other five were classified into a "malfunction" group. Five consecutive valve sounds for each valve were collected for the wavelet analysis in order to re-evaluate the previously proposed criteria and to measure both anterior spike area (Aa) and posterior spike area (Pa) for calculating the spike area ratio (Aa/Pa). The proposed criteria, namely, a single spike or coefficient of variation of <0.1120 detected only two of the five malfunctioning valves, as well as one normal valve to be malfunctioning. The mean Aa/Pa of all malfunctioning valves [2.45±0.63; 95% confidence interval (CI) ±1.01, 95% confidence limits (CL) 1.44-3.46] was significantly higher than that of all normal valves (1.17±0.27; 95% CI ±0.25, 95% CL 0.92-1.42). Based on this result, we determined the cutoff value of Aa/Pa to be 1.4. The combination of a single spike on the scalogram and an Aa/Pa of >1.4 detected more MBVs than previously proposed criteria. This combination may represent new criteria for detecting MBVs.

Role of vitelline envelope during fertilization in the black tiger shrimp, Penaeus monodon

Animal eggs possess investments through which sperm must penetrate. The aim of the present study was to investigate the role of the egg coating, the vitelline envelope, during sperm–egg interactions in the black tiger shrimp, Penaeus monodon. The site(s) of primary binding between sperm and egg and the possible binding molecule(s) for sperm were identified. In vitro adsorption of the vitelline envelope protein onto the sperm surface showed that primary binding occurred between the sperm anterior spike of acrosome intact sperm and the vitelline envelope. Results from streptavidin blotting revealed that the component of the vitelline envelope that interacts with the sperm integral membrane protein is a 370kDa protein. In addition, it was shown that the vitelline envelope protein had no ability to induce acrosome reaction. These results suggest that the function of the vitelline envelope is as a primary binding site for sperm in shrimp, but not a sole trigger for the acrosome reaction.

Multifocal spatiotemporal distribution of interictal spikes in Panayiotopoulos syndrome

To investigate the spatiotemporal course of interictal spikes in Panayiotopoulos syndrome (PS), and in particular whether seemingly independent extra-occipital spikes are truly autonomous or secondary, triggered by occipital spikes. Seven children with the most representative interictal spike patterns on visual analysis were studied. Five had a single focus (occipital in two, suggestive of posterior to anterior spike propagation in two, and frontal) and two had two foci over the posterior and the anterior areas independently. Spikes were marked, clustered and waveform - averaged, and mapped on electrode space. The patterns of spatial and temporal dynamics of the interictal spikes were not stereotypical for any brain area, including the occipital lobe. Some of the anterior and the posterior spikes remained focal or showed little spread, but others appeared to propagate to the opposite direction (occipital to frontal and vice versa). In PS all cerebral locations are able to spontaneously and independently generate and propagate interictal spikes, indicating that PS is a multifocal epileptic syndrome. Confirmation of the multifocal character of PS improves clinical diagnosis and challenges our current taxonomic concepts by expanding the anatomical boundaries of a distinct focal epilepsy phenotype from lobar to system.

Repeatability and Reproducibility of A-Scan Biometry Quantitative Findings

Purpose: To determine repeatability and reproducibility of A-scan biometry quantitative findings in order to uniformly evaluate lenticular cataract changes. Materials and Methods: Seventeen eyes from seventeen cataract patients were examined by three (trainee ophthalmologists). Results (ratio of mean internal lens spikes height/lens anterior surface spike height) were compared using coefficient of variation (CV), repeatability coefficient (CR), and intraclass correlation coefficients (ICC). Results: Intra-observer consistency was CV = 0.36, CR = 0.49, and ICC = 0.778 for the first operator; CV = 0.33, CR = 0.52, and ICC = 0.642 for the second operator; and CV = 0.32, CR = 0.53, and ICC = 0.567 for the third operator. Concerning inter-observer agreement: CV (in 6 of 7 eyes) was > 8%, CR was > 0.21, and intraclass correlation coefficient for all eyes was < 0.81. Conclusions: Regarding repeatability and reproducibility, although there is a tendency for statistical significance, variability of the results does not allow the use of the method as a complementary clinical tool for comparing results. Standardization of this procedure, in order to achieve higher test reliability, might be the aim of relevant future studies, although there are a number of points that have to be addressed.

Induction of the Acrosome Reaction in Black Tiger Shrimp (Penaeus monodon) Requires Sperm Trypsin-Like Enzyme Activity1

Trypsin-like enzymes in egg water (EW), a natural acrosome reaction (AR) inducer, are known for their importance in shrimp AR. In this report, we describe a unique phenomenon of the AR of black tiger shrimp (Penaeus monodon) sperm. It was completed within 45-60 sec and comprised only the acrosomal exocytosis and depolymerization of the sperm head anterior spike. We used peptidyl fluorogenic substrates to show the presence of trypsin-like enzymes in P. monodon EW and sperm, but minimal activities of chymotrypsin-like enzymes. In sperm, these trypsin-like enzymes existed both on the sperm surface and in the acrosome. The acrosomal enzyme was revealed as a 45-kDa band by fluorogenic substrate in-gel zymography. Although EW possessed high trypsin-like enzyme activities, they were not essential for the AR induction; EW pretreated with an irreversible trypsin inhibitor, or heat-inactivated EW (HI-EW), to abolish the trypsin-like activities could still induce the AR. The HI-EW-induced AR was inhibited by the presence of a membrane impermeant soybean trypsin inhibitor (SBTI) in the sperm suspension, indicating the significance of sperm-borne trypsin-like enzymes (on the surface and/or in the acrosome) in this AR process. However, pretreatment of sperm with SBTI followed by its removal from the suspension still allowed the AR to occur within 5 min of sperm exposure to HI-EW. Since trypsin-like activity of the SBTI-pretreated sperm surface at 5 min after SBTI removal was at the minimal level, our results suggest the importance of the acrosomal trypsin-like enzyme in the AR process.

Dynamic hip screw: does side make a difference?: Effects of clockwise torque on right and left DHS

A study was performed to assess the effect of clockwise rotational torque onto the fracture configuration in unstable intertrochanteric fractures. The premise is that rotational torque in the sagittal plane imparted during screw insertion can lead to a potentially unstable construct in LEFT-sided DHS fixations when compared to the RIGHT-sided ones. This unstable fixation construct manifests as an anterior spike of the proximal fragment in left-sided fixations due to clockwise torque. Eleven out of 30 unstable left-sided fractures showed an anterior spike compared with none in 26 right-sided fractures ( p<0.001). The study concludes that appropriate corrective measures of reducing the torque imparted is probably indicated in unstable left-sided fractures treated with a DHS.

Ulnar nerve injury following midshaft forearm fractures in children

We report three cases of ulnar nerve deficit in children following closed fractures of the forearm bones. Significant anterior angulation and displacement of the ulna was noted in all patients. Two patients were operated on at a later stage when no evidence of recovery was demonstrated; the ulnar nerve was found to be embedded in dense scar tissue. One patient was operated on at the time of injury; entrapment of the nerve on the anterior spike and partial transection was found. Early exploration is indicated in such cases and may result in full recovery.