A Compliant Instrument for Arthroscopic Joint Fusion

2004 ◽  
Author(s):  
Gabrie¨lle J. M. Tuijthof ◽  
Just L. Herder ◽  
C. Niek van Dijk ◽  
Peter V. Pistecky
Keyword(s):  
Subtalar Joint ◽  
Complex Shape ◽  
Invasive Approach ◽  
Joint Surfaces ◽  
Specific Shape ◽  
Mill Unit ◽  
Optimal Fusion ◽  
Smooth Contact ◽  
Contact Surfaces ◽  
The Difference

Due to its complex shape and its tightness, it is difficult to prepare the subtalar joint for fusion by means of a minimally invasive approach and conventional straight instruments. The preparation implies the establishment of bleeding contact surfaces. It is desirable to preserve the joint’s shape to keep congruent and smooth contact surfaces for optimal fusion. A compliant instrument was designed to facilitate the preparation by starting the design process from a clinically driven approach. The concept consists of a drill/mill unit at the tip that is steered through the joint by means of a passive automatic control. Since the joint will be fused, the cartilage and the subchondral bone layers should intentionally be damaged. This allows the use of the subtalar joint surfaces themselves as a guiding tunnel to preserve the joint’s shape. Thereto, a guidance frame was placed at the tip. The instrument is equipped with a special shaft that is compliant in one direction (perpendicular to the joint surfaces), and stiff in the two other directions to resist and transmit machining forces. The dimensioning of the instrument was performed by taking into account the specific shape of the subtalar joint. A prototype of the instrument was manufactured. The prototype is powered by a commonly used shaver system. The compliant instrument was tested in cadaver material, and gives promising results. In practice, the difference of the stiffness in y- and z-direction is at least a factor 100.

scholarly journals Evaluating the Subtalar Joint in Tibiotalocalcaneal Nail

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0040
Author(s):  
Megan Reilly ◽  
Kurosh Darvish ◽  
Soroush Assari ◽  
John Cole ◽  
Tyler Wilps ◽  
...  
Keyword(s):  
Surface Area ◽  
Subtalar Joint ◽  
Articular Surface ◽  
Joint Surface ◽  
Central Dome ◽  
Below The Knee ◽  
Joint Surfaces ◽  
Circular Surface ◽  
The Mean ◽  
Pass Through

Category: Hindfoot Introduction/Purpose: In tibiotalocalcaneal nails for arthrodesis, the path of the nail through the subtalar joint has not been well documented. Ideally, the defect caused by reaming and the nail does not pass through the joint surface so that the amount of bony contact between the talus and calcaneus is maintained in order to optimize fusion. Our hypothesis is that the TTC nail does not destroy a significant amount contact area between the talus and calcaneus. However, using larger diameter nails (which are inherently stronger) will have more of an effect on the contact surface. Methods: Five cadaveric below the knee specimens were obtained. The ankle was disarticulated on each specimen. Subsequently, a guidepin was drilled from the central dome of the talus down to the calcaneus. The 11 mm reamer was then passed over the guidepin through the calcaneus to simulate retrograde reaming of a TTC nail. Then, the subtalar joint was dissected open and the articular surface was documented in comparison with the area that was reamed out. Measurements were then made, using software that calculated two dimensional surface area to determine the percentage of actual subtalar joint area that was reamed out. The mean percentage of articular area that was removed with the reamer was then calculated. Results: Among the five specimens, in the calcaneus, the mean total articular area was 599mm2±113 and the mean drilled articular area was 21mm2±16. The percentage of the calcaneal articular surface that was removed with the reamer was 3.4%±1.9. In the talus, the mean total articular area was 782mm2±130 and the mean drilled articular area was 39mm2±18. The percentage of the talar articular surface that was removed with the reamer was 5.0%±2.3. Additionally, an 11 mm reamer makes a circular surface area of 95mm2, and the statistics above indicate that a significant portion of the reamed area is nonarticular, within the calcaneal sulcus or the talar sulcus. Conclusion: In a tibiotalocalcaneal nail the subtalar joint is typically incompletely visualized, however this anatomic study demonstrates that the 11 mm reamer eliminates about 3.4% of the calcaneal articular surface and about 5% of the talar articular surface. Therefore, the majority of the articular surface is left intact, which is ideal in optimizing arthrodesis outcomes. Furthermore, this study could extrapolate the effects of a larger nail on the availability of joint surface. It could also be used to argue for cartilage stripping of the affected joint surfaces in arthrodesis preparation, because the majority of the articular surface is, in fact, left intact.

scholarly journals Near-Storm Environments of Outbreak and Isolated Tornadoes

2018 ◽  
Vol 33 (5) ◽  
pp. 1397-1412 ◽  
Author(s):  
Alexandra K. Anderson-Frey ◽  
Yvette P. Richardson ◽  
Andrew R. Dean ◽  
Richard L. Thompson ◽  
Bryan T. Smith
Keyword(s):  
United States ◽  
Great Plains ◽  
Southeastern United States ◽  
Probability Of Detection ◽  
Geographical Region ◽  
Self Organizing Maps ◽  
Specific Shape ◽  
The Difference ◽  
Tornado Warning ◽  
Tornado Outbreaks

Abstract Between 2003 and 2015, there were 5343 outbreak tornadoes and 9389 isolated tornadoes reported in the continental United States. Here, the near-storm environmental parameter-space distributions of these two categories are compared via kernel density estimation, and the seasonal, diurnal, and geographical features of near-storm environments of these two sets of events are compared via self-organizing maps (SOMs). Outbreak tornadoes in a given geographical region tend to be characterized by greater 0–1-km storm-relative helicity and 0–6-km vector shear magnitude than isolated tornadoes in the same geographical region and also have considerably higher tornado warning-based probability of detection (POD) than isolated tornadoes. A SOM of isolated tornadoes highlights that isolated tornadoes with higher POD also tend to feature higher values of the significant tornado parameter (STP), regardless of the specific shape of the area of STP. For a SOM of outbreak tornadoes, when two outbreak environments with similarly high magnitudes but different patterns of STP are compared, the difference is primarily geographical, with one environment dominated by Great Plains and Midwest outbreaks and another dominated by outbreaks in the southeastern United States. Two specific tornado outbreaks are featured, and the events are placed into their climatological context with more nuance than typical single proximity sounding-based approaches would allow.

scholarly journals Reconstruction of input functions from a dynamic PET image with sequential administration of 15O2 and H215O for noninvasive and ultra-rapid measurement of CBF, OEF, and CMRO2

2017 ◽  
Vol 38 (5) ◽  
pp. 780-792 ◽  
Author(s):  
Nobuyuki Kudomi ◽  
Yukito Maeda ◽  
Hiroyuki Yamamoto ◽  
Yuka Yamamoto ◽  
Tetsuhiro Hatakeyama ◽  
...  
Keyword(s):  
Rate Constants ◽  
Human Subjects ◽  
Invasive Procedure ◽  
Invasive Technique ◽  
Invasive Approach ◽  
Non Invasive ◽  
Sequential Administration ◽  
Invasive Method ◽  
The Difference ◽  
Arterial Input Functions

CBF, OEF, and CMRO2 images can be quantitatively assessed using PET. Their image calculation requires arterial input functions, which require invasive procedure. The aim of the present study was to develop a non-invasive approach with image-derived input functions (IDIFs) using an image from an ultra-rapid O2 and C15O2 protocol. Our technique consists of using a formula to express the input using tissue curve with rate constants. For multiple tissue curves, the rate constants were estimated so as to minimize the differences of the inputs using the multiple tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects ( n = 24). The estimated IDIFs were well-reproduced against the measured ones. The difference in the calculated CBF, OEF, and CMRO2 values by the two methods was small (<10%) against the invasive method, and the values showed tight correlations ( r = 0.97). The simulation showed errors associated with the assumed parameters were less than ∼10%. Our results demonstrate that IDIFs can be reconstructed from tissue curves, suggesting the possibility of using a non-invasive technique to assess CBF, OEF, and CMRO2.

scholarly journals Results after Percutaneous and Arthroscopically Assisted Osteosynthesis of Calcaneal Fractures

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0019
Author(s):  
Wolfram Grün ◽  
Marius Molund ◽  
Fredrik Nilsen ◽  
Are Stødle
Keyword(s):  
Subtalar Joint ◽  
Operation Time ◽  
Clinical Results ◽  
Lateral Approach ◽  
Calcaneal Fractures ◽  
Invasive Approach ◽  
Extensile Lateral Approach ◽  
Arthroscopically Assisted ◽  
American Orthopaedic

Category: Arthroscopy, Trauma Introduction/Purpose: Surgical treatment of calcaneal fractures using the extensile lateral approach is associated with high rates of infection and soft tissue complications. During the last years there was a trend towards less invasive fixation methods. Percutaneous and arthroscopically assisted calcaneal osteosynthesis (PACO) combines the advantages of good visualization of the posterior facet of the subtalar joint with a minimally invasive approach. We have performed this technique since 2014 in selected Sanders II and III fractures. Methods: We conducted a clinical and radiographic follow-up of 19 patients with 20 calcaneal fractures which had been treated by PACO with a minimum follow-up of 12 months. The follow-up rate was 66% (19 of 29 patients). 18 men and 1 woman with a median age of 44 years (range, 21-65) and a follow-up period of 18 months (12-33) were examined. There were 11 Sanders II and 9 Sanders III fractures. Radiographs of all feet were obtained at final follow-up to evaluate the reduction of the fractures as well as the presence of osteoarthritis of the subtalar joint. Our primary outcome was the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score. Secondary outcomes were the Calcaneus Fracture Scoring System (CFSS), the Manchester- Oxford Foot Questionaire (MOxFQ), the Visual Analog Scale (VAS) for pain and the incidence of complications. Results: The patients were operated on after a median of 4 days after injury (range, 1-12). The operation time was 139.5 minutes (98-234). The patients were discharged 3 days (1-6) postoperatively. Postoperative radiographs showed a Böhler angle of 29.5 degrees (0-40). However, the follow-up radiographs showed subsidence of the fractures and a Böhler angle of 21 degrees (-16-36). 95% of the operated feet showed signs of posttraumatic subtalar osteoarthritis. There were no wound healing complications. Two patients were reoperated with screw removal due to prominent screws. The AOFAS score was 85 (50-100), the CFSS score 85 (26-100), the MOxFQ score 26.6 (0-73.4). The VAS pain score was 0 (0-5.7) at rest and 4 (0-8.2) during activity. Conclusion: Only a few articles have reported the outcome after percutaneous artroscopically assisted calcaneal osteosynthesis. Our results suggest that PACO gives good clinical results and a reduced risk of complications in selected calcaneal fractures. However, since this technique is technically challenging and has a steep learning curve, we expect to be able to further improve our results over time. Prospective longterm studies will be necessary to better document the potential advantages and limitations of this operating technique.

scholarly journals The Silverskold Test, Are We All Doing it the Same?

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Nicholas Cheney ◽  
Kyle Rockwell ◽  
John Weis ◽  
Dylan Lewis ◽  
Joseph Long ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Subtalar Joint ◽  
Senior Author ◽  
Foot And Ankle ◽  
Talonavicular Joint ◽  
Ankle Pain ◽  
Wide Range ◽  
Growing Body ◽  
Equinus Contracture ◽  
The Difference

Category: Pathophysiology Introduction/Purpose: Gastrocnemius eqiunus has been associated with a wide range of foot and ankle pathologies in the literature, however, many still question it’s involvement or existence. A recent response in Foot & Ankle International pointed out an incorrect demonstration of the Silfverskold test in a prior study. With a growing body of literature supporting gastrocnemius equinus as a contributing factor in foot and ankle pain, why do many feel that it still does not exist? It was our hypothesis that unless the examination is performed correctly, the diagnosis can be missed and could be the potential cause for disbelief in its existence or effect on foot and ankle pain. We sought to demonstrate the difference in examination findings when performing the test correctly and incorrectly. Methods: Thirty consecutive patients with conditions associated with gastrocnemius equinus in the literature were included in the study. Each patient was consented and had a Silverskold test performed correctly by inverting and locking the subtalar joint as well as stabilizing the talonavicular joint in order to isolate the ankle joint. We then performed the exam incorrectly without stabilizing the same two joints, allowing motion through the ipsilateral hindfoot and midfoot joints. A long arm goniometer was used to measure the angles with each arm along the length of the fibula and fifth metatarsal. The senior author performed all of the examinations to maintain consistency. The angles were recorded for later review. Results: We found that when the subtalar and talonavicular joints were stabilized, there was almost fifteen degrees less dorsiflexion than when the same joints were not stabilized. The average dorsiflexion when performed in the correct manner was seventy-eight degrees, while the average dorsiflexion with the exam performed incorrectly was ninety-three degrees. Conclusion: We demonstrated that if the examination is not performed correctly, the equinus contracture could go undiagnosed as motion through the hindfoot and midfoot joints can alter the findings. It is important to understand and perform the technique correctly to evaluate for the contracture as it has been shown to be a contributing factor in many foot and ankle problems. If we standardize the examination, there may be less disagreement about its existence or affect on foot and ankle pain.

Anatomic basis for a minimally invasive approach to the subtalar joint

2004 ◽  
Vol 124 (9) ◽  
pp. 621-625 ◽  
Author(s):  
G. Schmeiser ◽  
C. Kunze ◽  
M. Militz ◽  
V. B�hren ◽  
R. Putz
Keyword(s):  
Minimally Invasive ◽  
Subtalar Joint ◽  
Minimally Invasive Approach ◽  
Invasive Approach ◽  
Anatomic Basis

Elongation Behavior of Calcaneofibular and Cervical Ligaments during Inversion Loads Applied in an Open Kinetic Chain

1998 ◽  
Vol 19 (4) ◽  
pp. 232-239 ◽  
Author(s):  
Lewis P. Martin ◽  
Jennifer S. Wayne ◽  
Timothy J. Monahan ◽  
Robert S. Adelaar
Keyword(s):  
Range Of Motion ◽  
Subtalar Joint ◽  
Average Increase ◽  
Kinetic Chain ◽  
Calcaneofibular Ligament ◽  
Mechanical Methods ◽  
Different Types ◽  
Open Kinetic Chain ◽  
The Mean ◽  
The Difference

The cervical ligament plays a significant role in lateral stability of the subtalar joint but has received little attention compared with other ankle and subtalar joint ligaments. The purpose of this research was twofold. First, the elongation behavior of the cervical ligament was assessed with the calcaneofibular ligament intact and cut during two different types of inversion loads (manual and mechanical). Second, inversion range of motion was determined concomitantly with inversion loading and the difference in inversion range of motion between the calcaneofibular ligament intact to cut state was compared. The mean elongation of the cervical ligament with the calcaneofibular intact was 0.58 mm (± 0.33 mm) and 0.46 mm (± 0.23 mm) for manual and mechanical methods, respectively, and 0.88 mm (± 0.37 mm) and 0.78 mm (± 0.37 mm), respectively, for the same methods in the absence of the calcaneofibular ligament. This difference was statistically significant ( P < 0.05 manually and P < 0.02 mechanically). An average increase in the inversion range of motion was noted with both methods [7.5° manually (± 2.75°) and 7.7° mechanically (± 2.95°)] after lesioning of the calcaneofibular ligament. This difference was statistically significant ( P < 0.001) for both manual and mechanical range of motion testing. The results of this study indicate that there is a significant increase in elongation of the cervical ligament in the absence of the calcaneofibular ligament during manual and mechanically applied inversion loads in a open kinetic chain. Clinical and theoretical implications of this data are discussed.

An Upsetting - Ironing Type Tribo-Meter for Evaluating Tribological Performance of Lubrication Coatings for Cold Forging

2013 ◽  
Vol 535-536 ◽  
pp. 243-246 ◽  
Author(s):  
Masatoshi Hirose ◽  
Zhi Gang Wang ◽  
Shinobu Komiyama
Keyword(s):  
Evaluation Method ◽  
Complex Shape ◽  
Evaluation Methods ◽  
Tribological Performance ◽  
Test Method ◽  
Cold Forging ◽  
Lubrication Performance ◽  
Processing Modes ◽  
Surface Expansion ◽  
The Difference

In recent years, many attempts are being made to develop new lubrication coatings for cold forging. In general, an alternative coating is designed based on the results of the evaluation methods that simulate the frictional condition of cold forging. Various evaluation methods have been proposed and used to design an alternative coating according to the processing purpose. However a lot of parts are manufactured by the multistage forging machine such as parts forming machine, complex shape being produced recently by combined processing. A lubrication coating in such an environment is exposed to repeatedly in a variety of processing modes, and received serious damage. At present the performance of an alternative coating isn’t enough to satisfy needs of market in such a multistep forging. Development of lubricant that can satisfy such demands needs a new evaluation method. This comes the purpose of this study. An newly devised tribometer consists of an ironing process after upsetting process. We designed this test method by using finite element(FE) analysis. In upsetting, damage to the lubrication coating is given by the expansion of free surface. In ironing, the performance of lubrication coating destroyed by upsetting is evaluated. By using the upsetting-ironing type tribometer, the lubrication performance under a large surface expansion and a high pressure can be evaluated. In addition, the degree of coating damage can be adjusted by changing upset ratio and height of billet. The difference in the lubrication performance of the bonderised and the prototype alternative coating was examined by this evaluation method.

scholarly journals Biomechanical Comparison of Plantar-To-Dorsal and Dorsal-To-Plantar Screw Fixation Strength for Subtalar Arthrodesis

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0036
Author(s):  
Ramon Rodriguez ◽  
Schouchen Dun ◽  
Jun Kit He ◽  
Haley McKissack ◽  
Glenn S. Fleisig ◽  
...  
Keyword(s):  
Subtalar Joint ◽  
Statistical Significance ◽  
Fixation Strength ◽  
Hard Data ◽  
Subtalar Arthrodesis ◽  
Significant Difference ◽  
Fixation Techniques ◽  
The Difference ◽  
Student’S T ◽  
Dorsal Fixation

Category: Basic Sciences/Biologics, Hindfoot Introduction/Purpose: Arthrodesis of the subtalar joint is performed for various arthritic and instability problems to correct alignment and relieve pain. For talocalcaneal pathologies, isolated subtalar arthrodesis has been advocated with the advantages of lower risk of adjacent joint arthritis and nonunion of the transverse tarsal joint. Internal fixation techniques have varied over time and use of compression screws is common. The screws may be oriented from dorsal to plantar or plantar to dorsal. Arguments favoring one approach over another are based more on “expert opinion” than hard data. The goal of this study was to compare the biomechanical stability of these two constructs to evaluate which creates a more stable construct. Methods: Eight matched pairs of cadaver feet underwent subtalar joint arthrodesis with two 7.3-mm cannulated screws. Randomization was used to assign screw orientation, such that one foot in each pair was assigned dorsal to plantar screw orientation (DP group), and the other foot plantar to dorsal orientation (PD group). Standard surgical technique with fluoroscopy was used for each approach. Following fixation, each specimen was loaded to failure with a Bionix 858 MTS device, applying a downward axial force at a distance to create torque. Torque to failure was compared between DP and PD groups using Student’s T-test, with p = 0.05 used to determine statistical significance. Results: The force to failure was 585.9 ± 201.1 N for the plantar-to-dorsal fixation and 667.2 ± 449.4 N for the dorsal-to-plantar fixation. The moment arm was 55.1 ± 4.7 mm for the dorsal-to-plantar fixation and 54.8 ± 3.9 mm for the plantar-to-dorsal fixation. Statistical analysis demonstrated that the mean torque to failure slightly favored the DP group (37.3 N-m) to the PD group (32.2 N-m). However, the difference between the two groups was not statistically significant (p = 0.55). Conclusion: There is no significant difference in strength between subtalar arthrodesis performed with dorsal-to-plantar screw orientation and plantar-to-dorsal screw orientation. This suggests that selection of technique should depend on the situation and the required advantages of each. Placing the screw from the heel up has the benefit of being an easier approach, allows access to tenser talar bone once the screw is through, and has less risk of neurovascular injury. The dorsal-to-plantar technique allows simple supine positioning of the patient, needs only two fluoroscopic views to check pin position, and allows the surgeon to manipulate the foot more easily.

Adhesive Gripping Elements in a Construction of Gripping Heads

2015 ◽  
Vol 772 ◽  
pp. 339-343
Author(s):  
Marcel Horák ◽  
František Novotný
Keyword(s):  
Contact Surface ◽  
Carrying Capacity ◽  
Smooth Contact ◽  
Contact Surfaces ◽  
Plastic Products

The paper describes possibilities to use industrially adhesive gripping elements in automatized handling processes especially for flat objects but also for objects slightly dissected according to height (e.g. sheets of glass, plastics, metals, plastic products etc.) which have dry, relatively clean, and smooth contact surfaces. It begins by analyzing results obtained in the field of designing combined vacuum-adhesive gripping elements, and the exclusively adhesive (passive) ones being suitable for technologically difficult handling conditions, e.g. in vacuum, as well. Furthermore, problems of the maximum carrying capacity of individual gripping elements being arranged parallel on a frame of a multi-element gripping head. A new concept of a compensation module of the gripping element position is presented as well, namely in relation to the head frame and to the handling object contact surface dissected according to height.

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