Pin Insertion Research Articles

Review on Joining Process of Carbon Fiber-Reinforced Polymer and Metal: Methods and Joining Process

The use of carbon fiber-reinforced polymer (CFRP) in aviation, automobile, marine and offshore, etc. increases sharply. The metals such as aluminum alloy are still widely used in these industries. Then, the joining technology of CFRP-metal is one of the key problems urgently to be solved and developed in these industries, especially in aviation industries. Thus, this paper gives a review on the joining processes of carbon fiber-reinforced polymer and metal. The implementation processes and joining material types of adhesive bonding, bolt connection, riveting, welding, “z-pin” (pin inserts), and joining (such as self-pierce riveting, hot riveting, mechanical clinching, friction welding) by plastic deformation, were summarized.

MRI Tracking of the Effect of Bioabsorbable Pins on Bone Marrow Edema After Fixation of the Osteochondral Fragment in the Talus.

Large osteochondral lesions of the talus (OLT) with good articular cartilage can be fixed by using bioabsorbable pins. These pins have various advantages but they can have adverse effects such as foreign body inflammation. This negative impact of pins on subchondral bone can be seen as bone marrow edema (BME) on magnetic resonance imaging (MRI). The purpose of this study was to investigate the course of change in BME on MRI, including osteolytic change around pins in OLT treated with pin fixation. This study comprised 13 ankles in 12 patients, who underwent surgeries to fix an OLT using poly-l-lactide acid pins. MRIs were taken at preoperative, 3, 6, and 12 months after surgery. The area of BME was measured at each time point, and osteolytic change around pins was evaluated. Moreover, pin insertion angle was measured. BME significantly decreased from preoperative to 6 and 12 months. At 1 year, 28.1% of pins exhibited osteolytic change around them. Pin insertion angle was significantly lower in those with osteolytic change than those with no osteolytic change. At 3 and 6 months and 1 year postoperatively, BME with osteolytic change was significantly greater than those patients with no osteolytic change. The American Orthopaedic Foot & Ankle Society score significantly improved from preoperative (76.6±3.4 points) to 1 year after surgery (98.5±3.8 points). A shallow pin insertion angle was associated with osteolytic change around pins and persistence of BME on MRI, although excellent results were obtained at 1 year after surgery. Level III, retrospective comparative series.

Delamination resistance of composite laminated structures reinforced with angled, threaded, and anchored Z-pins

The delamination resistance of Z-pinned laminates is directly dependent on the strength of the pin–laminate bonding at the interface. In this paper, we investigate novel approaches to the Z-pinning technology in order to increase delamination strength via enhancing mechanical interlocking of the pins. Toward this end, we study the effect of pin insertion at an angle to the vertical in contrast to the conventional vertical pin insertion. Subsequently, a novel variety of pin, namely the threaded pin, is studied as a candidate for reinforcement which increases mechanical interlocking between the pin and the laminate as well as the epoxy-pin contact area, thus delaying delamination. In addition, the effect of anchoring reveals the length of smooth metal pins on to the surface of the laminate before curing on delamination strength is investigated. Experiments performed show increase in tensile pullout strengths when angled, threaded, or anchored pins are used. These experimental results for tensile pullout strengths validate nonlinear finite element models incorporating cohesive zones at the pin–laminate interface. In addition, fracture toughness and delamination resistance under mode-I loading are investigated by performing experiments on double cantilever beam specimens. Results demonstrate the superior delamination resistance properties for angled, threaded, and anchored pin inserts.

Advantages and disadvantages of the prone position in the surgical treatment of supracondylar humerus fractures in children. A literature review

IntroductionSupracondylar humerus fractures are the most common elbow injuries in children. The widely adopted approach for Gartland III extension type consists of closed reduction and percutaneous pinning; the pin configuration can be lateral or crossed in relationship with the habit of the surgeons. Iatrogenic injury of the ulnar nerve is the most common risk during the insertion of the medial pin. The aim of this study was to analyze advantages and disadvantages of percutaneous pinning with the patient in prone position. Materials and MethodsA literature review of the period 2005–2017 was carried out; four medical search engine (Pubmed, Cochrane Library, ISI Web of Science and Scopus) were consulted using the review’s filter and the key words “Ulnar nerve AND supracondylar humerus fractures”. The total number of patients were analyzed for: ulnar nerve injuries, anesthesiologic management, time of surgery. ResultsTwenty-nine papers were read, 23 regarding cross pinning in supine position and 6 in prone position. On one hand, 1529 children were treated with closed reduction and cross pinning in supine position; 69 of these patients (4.5%) suffered from iatrogenic ulnar nerve injury. On the other hand, 579 patients underwent the same treatment in prone position; no ulnar nerve lesions were reported in this group. Only one article compared both groups of children in supine and prone position regarding time of anesthesia which is slightly higher in the prone group. There were no differences between supine and prone positions regarding x-ray exposition, time of surgery, closed reduction manoeuvers, pin positioning, x-ray results, clinical and functional results. Discussion and ConclusionsThe ulnar nerve in children is hypermobile in the cubital tunnel and tends to dislocate anteriorly over the medial epicondyle, especially when the elbow is in hyperflexion. This may be the reason of the increased risk of nerve injury during the insertion of the medial pin in supine position and, instead, an advantage of the prone position. The insertion of both pins from the lateral side could reduce this complication. Larger studies need to be carried out regarding the reported higher duration of anesthesia in prone position.

Evaluation of microdamage initiation in Z-pinned laminates by means of automated RVE computations

Z-pinning was originally designed to improve the delamination toughness and the impact resistance of composite laminates. However, there is extensive experimental evidence that this improvement is accompanied by a reduction of the in-plane properties. The main mechanisms responsible for this deterioration are the local change in fiber content, fiber distortion, and the inclusion of resin-rich regions near the Z-pin. The shape of these geometrical features strongly depends on the laminate stacking sequence and on pin parameters such as pin diameter, pin content, and initial pin inclination angle. Their shape complexity challenges analytical modelling approaches which are currently used to generate RVE geometries for simulations.A computational approach is presented to generate such geometrical models. Resin-rich regions are modelled by initially straight discretized lines which are gradually shaped by a set of geometrical operations mimicking pin insertion, pin rotation and fiber deflection. Fiber distortion is modelled in a post-processing stage in cross-sections accounting for the preservation of the amount of fibers. These models are then transformed into finite element mechanical models in order to investigate how local fiber volume fraction changes, fiber misalignment, or distortions in reinforcement due to pin rotation, affect the global stiffness and local stress concentrations.

Effect of Bidirectional Insertion of External Skeletal Fixation Pins on Axial Pullout Strength in Canine Cadaveric Bone

Effect of Bidirectional Insertion of External Skeletal Fixation Pins on Axial Pullout Strength in Canine Cadaveric Bone

ITimerM

As designs continue to grow in size and complexity, EDA paradigm shifts from flat to hierarchical timing analysis. In this article, we present compact and accurate timing macro modeling, which is the key to efficient and accurate hierarchical timing analysis. Our goal is to contain only a minimal amount of interface logic in our timing macro model. The main idea is to separate the interface logic into variant and constant timing regions. Then, the variant timing region is reserved for accuracy, while the constant timing region is reduced for compactness. For reducing the constant timing region, we propose anchor pin insertion and deletion by generalizing existing timing graph reduction techniques. Furthermore, we devise a lookup table index selection technique to achieve high model accuracy over the possible operating condition range. Compared with two common models used in industry, extracted timing model and interface logic model, our model has high model accuracy and small model size. Based on the TAU 2016 and 2017 timing macro modeling contest benchmark suites, our results show that our algorithm delivers superior efficiency and accuracy: Hierarchical timing analysis using our model can significantly reduce runtime and memory compared with flat timing analysis on the original design. Moreover, our algorithm outperforms TAU 2016 and 2017 contest winners in model accuracy, model size, model generation performance, and model usage performance.

Z-pin insertion process for through-thickness reinforced thermoplastic composites

This paper presents a novel method for the ultrasonically assisted insertion of metallic z-pins into thermoplastic composites. Mechanical and microstructural investigations were carried out on glass fiber-reinforced polyamide and polypropylene specimens. The insertion of steel pins into thermoplastic composites led to microstructural changes that differ significantly from the known microstructure of z-pinned thermoset fiber-reinforced plastics. Optical microscopy showed an absence of notable fiber waviness and resin-rich zones around each pin. Instead, the fibers were predominantly deflected in the through-thickness direction by the high insertion forces arising during pin penetration. To gain an initial insight on the resulting properties of the z-pin/thermoplastic interface, the mechanical properties of z-pinned thermoplastic composites under mode I loading were investigated using pullout tests. For reference, the pullout behavior of thermoset carbon fiber-reinforced plastic specimens, reinforced with steel pins was determined too. Due to the poor bonding and lack of friction between the pin and laminate, the determined traction loads of the thermoplastic specimens are well below typical values achieved from pin pullout in thermoset laminates.

Dynamic finite element analysis of implants for femoral neck fractures simulating walking.

To examine postoperative complications for osteosynthesizing femoral neck fractures (Pauwels III), biomechanical analysis should be conducted under dynamic conditions simulating for walking, not static conditions. Among the two main aims of this study, one is to pioneer the technique of dynamic finite element (FE) analysis, and the other is to compare stress distribution between two implants during walking. First, we performed an inverse dynamic analysis with optimization method using a musculoskeletal model to calculate the inter-segmental and muscular forces during walking. Second, three FE models were prepared: (I) intact hip joint, (II) fractures treated with two Hansson pins (HP), and (III) fractures with Dual SC Screws (DSCS) maintaining an angular stability. The direction and magnitude of the loadings varied continuously. Stress distribution during the walking was evaluated by using a dynamic explicit method. We examined the time-dependent von Mises stresses at two representative spots: medial cortex at the femoral neck fracture site and lateral pin (presumed) insertion holes. In general, stress values are always changing during walking cycle. Regarding medial femoral neck cortex at the fracture line, intact model showed almost consistent value. Both HP model and DSCS model amounted the highest around 30 MPa. At lateral holes, highest values were 18.8, 104.0, and 63.1 MPa of intact, HP, and DSCS models, respectively. Thus, our analysis simulating the real walking will be useful in evaluating time-varying stress distribution to assess postoperative complication. DSCS is expected to be paramount for treatment of unstable femoral neck fractures.

Miniature LVDT setup for local strain measurement on cement-treated clay specimens

ABSTRACTMiniature submersible linear variable differential transformer (LVDT) is commonly used for small strain stiffness measurement. However, it has not been widely used on cement-treated clays. This paper proposes a method of installing and setting up submersible LVDT to minimize testing problems and errors for cement-treated clays. In soft clay testing, the LVDT mount can be anchored to the specimen by pressed-in anchor pins or rods. However, this cannot be done on cement-treated clay due to the latter’s hardness. Preliminary trials also indicate that direct attachment of the LVDT mounts to the membrane without anchor pins is not feasible owing to the tendency of the LVDT to tilt and detach from the specimen. The system adopted involves pre-casting holes for the insertion of anchor pins during placement of the admixture into the moulds. The diameter of the anchors pins was found to have significant effect on the results; smaller diameter pins give more consistent results with those of resonant column and bender element tests. This can be attributed to the effect of stress concentration around the anchor pins. The results showed that, used appropriately, submersible LVDTs can give small strain measurements which have a high degree of inner consistency with results from resonant column and bender element tests.

Robotic tool positioning process using a multi-line off-axis laser triangulation sensor

Proper positioning of a friction stir welding head for pin insertion, driven by a closed chain robot, is important to ensure quality repair of cracks. A multi-line off-axis laser triangulation sensor was designed to be integrated to the robot, allowing relative measurements of the surface to be repaired. This work describes the sensor characteristics, its evaluation and the measurement process for tool positioning to a surface point of interest. The developed process uses a point of interest image and a measured point cloud to define the translation and rotation for tool positioning. Sensor evaluation and tests are described. Keywords: laser triangulation, 3D measurement, tool positioning, robotics.

Evaluation of the Hemodynamic Response of Intravenous Clonidine versus Ropivacaine Scalp Block to Insertion of Scalp Pins in Neurosurgical Patients.

Background:The application of the skull-pin head-holder, used to stabilize the head during neurosurgical procedures, produces an intense nociceptive stimulus and results in abrupt increases in blood pressure and cerebral blood flow under general anesthesia. Different anesthetic and pharmacologic techniques, including local anesthetics, narcotics, antihypertensives, and deepening of anesthesia with inhalation anesthetics, have been used to blunt this deleterious effect with variable success.Aim:To compare the analgesic and hemodynamic effects of ropivacaine scalp block, and intravenous (IV) clonidine in attenuating the hemodynamic response to the scalp pin insertion in neurosurgical patients.Settings and Design:A comparative two group's clinical study of 64 patients undergoing elective craniotomy in Department of Anaesthesiology, Bangalore Medical College and Research Institute.Methodology:Sixty-four patients were allocated into any one of two groups of 32 patients each, by means of computer-generated randomization: (1) Group S: Patients receiving scalp block with injected ropivacaine 0.25% 30 ml. (2) Group C: Patients receiving 2 μg/kg IV clonidine.Statistical Methods:Descriptive and inferential statistical analysis has been carried out in the present study. Results on continuous measurements are presented on mean ± standard deviation (minimum–maximum) and results on categorical measurements are presented in number (%). Significance is assessed at 5% level of significance.Results:Increase in heart rate and blood pressure during pin insertion was attenuated by clonidine hydrochloride (P < 0.001). The number of patients who required more fentanyl and propofol to stabilize the hypertensive response were more in control group than clonidine group.Conclusion:IV clonidine maximally attenuated the hemodynamic response to application of head pins in a dose of 2 μg/kg compared to ropivacaine scalp block, thus maintaining intracranial pressure for neurosurgical anesthesia.

Unicortical self-drilling external fixator pins reduce thermal effects during pin insertion

IntroductionExternal fixation is associated with the risk of pin loosening and pin infection potentially associated to thermal bone necrosis during pin insertion.ObjectiveThis study aims to investigate if the use of external fixator systems with unicortical pins reduces the heat production during pin insertion compared to fixators with bicortical pins.MethodsPorcine bone specimens were employed to determine bone temperatures during insertion of fixator pins. Two thermographic cameras were used for a simultaneous temperature measurement on the bone surface (top view) and a bone cross-section (front view). Self-drilling unicortical and bicortical pins were inserted at different rotational speeds: (30–600) rpm. Maximum and mean temperatures of the emerging bone debris, bone surface and bone cross-section were analyzed.ResultsMaximum temperatures of up to 77 ± 26 °C were measured during pin insertion in the emerging debris and up to 42 ± 2 °C on the bone surface. Temperatures of the emerging debris increased with increasing rotational speeds. Bicortical pin insertion generated significantly higher temperatures at low insertion speed (30 rpm)ConclusionThe insertion of external fixator pins can generate a considerable amount of heat around the pins, primarily emerging from bone debris and at higher insertion speeds. Our findings suggest that unicortical, self-drilling fixator pins have a decreased risk for thermal damage, both to the surrounding tissue and to the bone itself.

Biomechanical analysis of four external fixation pin insertion techniques.

Having multiple external fixation pin designs and insertion techniques has led to debate as to which combination creates the stiffest construct. This study sought to biomechanically evaluate construct strength using self-drilling (SD) and self-tapping (ST) pins inserted with either bicortical or unicortical fixation. SD and ST 5.0 mm stainless steel pins were used in combination with bicortical self-drilling (BCSD), bicortical self-tapping (BCST), unicortical self-drilling (UCSD), and unicortical selftapping (UCST) techniques. Pre-drilling for the self-tapping pins was completed with a 4.0 mm drill bit using ¾ inch polyvinyl chloride (PVC) pipe as the insertional medium. The PVC pin constructs were then loaded to failure in a cantilever bending method using a mechanical testing system. Ten trials of each technique were analyzed. BCSD insertion technique had the highest maximum failure force and stiffness of all tested techniques (P&lt;0.0001). SD pins were significantly stronger to bending forces than ST pins in both the unicortical and bicortical setting (P&lt;0.0001). Three point bending tests of the 5.0 mm SD and ST threaded area showed that threaded portion of the SD pins had a 300 N greater maximum failure force than the ST pins. Biomechanical analysis of external fixation pin insertion techniques demonstrates that bicortical fixation with SD pins achieved the greatest resistance to bending load. Despite both pins being 5.0 mm and constructed from stainless steel, ST and SD behaved differently with regard to maximum failure force and stiffness. This study demonstrates that insertion technique and pin selection are both important variables when attempting to achieve a stiff external fixation construct.

Hemodynamic and Bispectral Changes During Pin Insertion in Craniotomy - Effect of Locally Infiltrated Bupivacaine.

Introduction Cranial pins insertion is a method for head stabilization and together with the scalp incision is one of the biggest noxious stimulus associated with arousal and rapid increase of the blood pressure leading to pathological increase of the intracranial pressure. The aim of this investigation is to study the superiority of the locally infiltrated anesthetic bupivacaine just before the skull pin insertion and the scalp incision in craniotomy under general anesthesia. Methods In the study thirty patients of both genders aged 24-72 years were included. They were categorized as ASA 1 and 2 and divided into two group of 15 patients each, group B (bupivacaine) and group S (saline). We recorded the bispectral (BIS) index, the mean arterial pressure (MAP) and the pulse rate (PR) in five time intervals: t 0-2 min before pin insertion; t 1-2 min after pin insertion; t 2-5 min after; t 3-10 min after and t 4-15 min after. Results Significant difference p<0.05 was achieved in group S for all three followed parameters: blood pressure, heart rate and bispectral index. The difference is present in all four time intervals compared to the initial one before the pin insertion. With further analysis it was demonstrated that the investigated BIS index participates the most in the overall significance in group F. Conclusion The scalp infiltration with local anesthetic bupivacaine results with stable hemodynamic parameters and stable intracranial pressure during the painful procedures as craniotomy.

Management of Pediatric Atlantoaxial Rotatory Subluxation with a Simple Handmade Cervical Traction Device: Doing More with Less

To introduce a novel traction device for management of pediatric atlanto-axial rotatory subluxation (AARS) in source limiting areas. Atlanto-axial (C1-C2) joint is accountable for up to two third of total axial craniocervical rotation. Its major role in pivotal rotation of cervical spine makes it more vulnerable to a certain type of injury known as AARS. Management of AARS is based on the Fielding classification which includes closed reduction and immobilization and cervical fusion in unstable cases. There are several cervical traction devices including the Gardner-Wells tongs and halter traction device. All the available devices require insertion of pins into the calvarial periosteum which is a painful, invasive and intolerable procedure especially for the pediatric patients. We designed a simple hand-made cervical traction device which is composed of 2 soft padded straps (40 × 4 cm) and 2 connecting strings which can be applied easily under the chin and occipital areas of the patients. We successfully treated a 9-year-old girl with AARS with the device. The advantage of the device is its available, inexpensive and non-invasive and the patient might tolerate it more easily compared to the previously designed instruments. This hand-made simple cervical traction device in source limiting centers and hospitals is a good example of doing more with less. It was effective and the tolerance of the patient was acceptable. Further studies with larger series are required for providing appropriate evidence.

Prospective study of unstable distal radius fractures treated with external fixation in Indian rural set-up

Aim: Distal radius fracture is common fracture in daily orthopaedic practice accounting for 1/6th of all the fractures. Conventionally the fractures were treated with closed reduction and immobilization with casts. Even though union of these fractures occurs, they have a very high incidence of going in for malunion and wrist joint instability especially with comminution & intra articular extension cases. Moreover a change in trend to younger age groups as a result of RTA’s (road traffic accidents) & trauma is leading to more complicated fractures with intraarticular extension and comminution. Also the importance of anatomical alignment and reconstruction of radiocarpal and radioulnar ulnar joints has been emphasized in recent trends. Hence the management of distal radius fractures changed from universal use of cast immobilisation to operative interventions. Aim of this study is to observe the effect of external fixation for unstable distal radius fractures in rural set up. Materials and methods: Prospective analysis of 30 patients with unstable distal radius fractures, who were operated at MIMS hospital, nellimarla village, vizianagaram district between may 2016 to feb 2017 treated with external fixator. Patient position- supine with arm table support. For external fixation of the wrist we used the 4 mm (small) external fixator system. For pin insertion into the second metacarpal, the distal pin is inserted proximal to the transition of the metacarpal head into the shaft and the more proximal pin is inserted distal to transition of the shaft into the metacarpal base.The proximal two pins are inserted proximal to the muscle bellies of abductor pollicis longus (APL) and extensor pollicis brevis (EPB). Proximal to these muscles, the radial shaft is palpated through the skin between the bellies of the extensor digitorum communis (EDC) and extensor carpi radialis longus/brevis (ECRL/ ECRB) over a distance of 3-4 cm at which the proximal pins inserted into the radial shaft with 4-5cms apart. Longitudinal traction is applied on the thumb and index finger or the distal partial frame to reduce the fracture. T clamps are fixed to bridging rods, first proximally followed by tightening of distal fragment T clamps to maintain the traction and reduction, there by healing of fracture by the principle of ligamentotaxis. Results: Average Mean hospital stay is 4days, there are 13males and 17 females between age group 28-60yrs, 27 cases out of 30 had functional and radiological union by 12weeks (range 6-18 weeks), 2 had pin track infection which were treated successfully with iv antibiotics. 1 patient had deep bone infection and pin loosening which was managed with external fixator removal, long course antibiotics and casing. We followed standard Sarmiento radiological scoring system, Gartland and Werley Score (demerit system) demerit point scoring system, DASH scores, Green & O Brien grade scoring systems to evaluate the end results. Conclusion: External fixation of unstable distal radius fractures can be considered as effective treatment in elderly populations of Indian rural set up as it is simple, cost effective, short duration procedure with good results.

Improving the Transient Thermal Fatigue Life of a Gas Turbine Casing by Drilling Stop Holes and Inserting Pins into Them

Gas turbines casings are susceptible to cracking at the edge of the eccentric pin hole. Thispaper describes the improvement of the transient thermal fatigue life of gas turbines casings through theapplication of pins. The repair technology under consideration involved drilling a number of holes inthe gas turbines casing along the crack and inserting pins into them. The crack position and directionwere determined using non-destructive tests. A series of finite element models were developed andtested in AStM-A395 elastic-perfectly plastic ductile cast iron. In some specimens, holes were drillednear the crack tips. Pins were inserted into the holes in some cases. Abaqus software finite elementpackage and Zencrack fracture mechanics code were used for modeling. The efficiency of crack repairby the installation of pins was investigated along with the effect of the number of pins on crack repairefficiency. The result shows that the insertion of pins into holes drilled in the vicinity of the crack tips isan effective method of retarding crack growth in a gas turbine casing.

A new approach to local DCO in ankle fracture dislocations: external fixation with diaphyseal unicortical screws applied by local anaesthesia.

Ankle fracture dislocations represent a great threat for soft tissue viability and articular instability. The use of a temporary ankle bridging ExFix plays a fundamental role in the local damage control orthopaedics while waiting for definitive synthesis. For this prospective research, we have developed a full application protocol of innovative diaphyseal monocortical screws fixator (Unyco-OrthofixTM) exclusively under local anaesthesia. Rigid selection criteria allowed us to collect nine patients during a period of almost 2years. VAS score was analysed for the feasibility of the procedure, and a thorough radiologic evaluation was performed. Results pointed out that the calcaneus pin insertion (VAS: 3.44) followed by the local anaesthetics injection (VAS: 3.22) was the most painful, without precluding to continue the procedure; fracture temporary stability was achieved in all the cases. The procedure of monocortical diaphyseal application in bridging external fixation is comparable to the conventional transcalcaneal traction maintaining the advantage in terms of speediness, independence from anaesthetists and feasibility within few minutes from hospital admittance even in patients under anticoagulants therapy, but increasing the stability of the reduction and improving the quality of nursing (so-called portable traction).

CUSTOMIZED GUIDE FOR FEMORAL COMPONENT POSITIONING IN HIP RESURFACING ARTHROPLASTY.

ABSTRACTObjective: To prove the accuracy of a customized guide developed according to our method. Methods:This customized guide was developed from a three-dimensional model of proximal femur reconstructed using computed tomography data. Based on the new technique, the position of the guide pin insertion was selected and adjusted using the reference of the anatomical femoral neck axis. The customized guide consists of a hemispheric covering designed to fit the posterior part of the femoral neck. The performance of the customized guide was tested in eight patients scheduled for total hip arthroplasty. The stability of the customized guide was assessed by orthopedic surgeons. An intraoperative image intensifier was used to assess the accuracy. Results: The customized guide was stabilized with full contact and was fixed in place in all patients. The mean angular deviations in relation to the what was planned in anteroposterior and lateral hip radiographs were 0.5º ± 1.8º in valgus and 1.0º ± 2.4º in retroversion, respectively. Conclusion: From this pilot test, the authors suggest that the proposed technique could be applied as a customized guide to the positioning device for hip resurfacing arthroplasty with acceptable accuracy and user-friendly interface. Level of Evidence IV, Cases Series.