Three-dimensional (3D) printing has numerous applications and has gained much interest in the medical world. The constantly improving quality of 3D-printing applications has contributed to their increased use on patients. This paper summarizes the literature on surgical 3D-printing applications used on patients, with a focus on reported clinical and economic outcomes. Three major literature databases were screened for case series (more than three cases described in the same study) and trials of surgical applications of 3D printing in humans. 227 surgical papers were analyzed and summarized using an evidence table. The papers described the use of 3D printing for surgical guides, anatomical models, and custom implants. 3D printing is used in multiple surgical domains, such as orthopedics, maxillofacial surgery, cranial surgery, and spinal surgery. In general, the advantages of 3D-printed parts are said to include reduced surgical time, improved medical outcome, and decreased radiation exposure. The costs of printing and additional scans generally increase the overall cost of the procedure. 3D printing is well integrated in surgical practice and research. Applications vary from anatomical models mainly intended for surgical planning to surgical guides and implants. Our research suggests that there are several advantages to 3D-printed applications, but that further research is needed to determine whether the increased intervention costs can be balanced with the observable advantages of this new technology. There is a need for a formal cost–effectiveness analysis.

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3D-printing techniques in a medical setting: a systematic literature review

➤ Although multiple theories have been proposed, no one pathophysiologic mechanism has been identified as the etiology for the development of osteonecrosis of the femoral head. However, the basic mechanism involves impaired circulation to a specific area that ultimately becomes necrotic.➤ A variety of nonoperative treatment regimens have been evaluated for the treatment of precollapse disease, with varying success. Prospective, multicenter, randomized trials are needed to evaluate the efficacy of these regimens in altering the natural history of the disease.➤ Joint-preserving procedures are indicated in the treatment of precollapse disease, with several studies showing successful outcomes at mid-term and long-term follow-up.➤ Studies of total joint arthroplasty, once femoral head collapse is present, have described excellent outcomes at greater than ten years of follow-up, which is a major advance and has led to a paradigm shift in treating these patients.➤ The results of hemiresurfacing and total resurfacing arthroplasty have been suboptimal, and these procedures have restricted indications in patients with osteonecrosis of the femoral head.

Nontraumatic Osteonecrosis of the Femoral Head: Where Do We Stand Today?: A 5-Year Update

Background: Coronal malalignment occurs frequently in total knee arthroplasty (TKA) and reduces implant longevity and function. Designed to improve consistency and efficiency, patient- specific positioning guides (PSPG) generated from preoperative imaging studies represent a paradigm shift from manual instrumentation (MI) and intraoperative computer navigation. Purposes: We compare the efficacy of PSPG to MI in (1) restoring mechanical axis of the extremity and (2) achieving neutral alignment of the femoral and tibial components. Methods: We retrospectively examined 696 postoperative anteroposterior standing long-leg radiographs after TKA (545 PSPG, 151 MI) by two surgeons. Coronal alignment was assessed by determining the zone in which the overall mechanical axis (OMA) passed through the knee, measuring the hip-knee-ankle (HKA) angle between the tibial and femoral mechanical axes, and finally, noting the alignment of the femoral and tibial components with respect to their mechanical axes. Results: The OMA passed through the central third more frequently with PSPG than MI for both surgeons (JHD: 86.6% vs. 77%, p = 0.02; AVL: 86.4% vs. 74.5%, p = 0.11). For the senior author, while percent of HKA outliers >3i,° was similar between PSPG and MI, the mean error from neutral for these patients was significantly less with PSPG than MI (4.50i,° vs. 5.25i,°, p = 0.0031). The tibial component demonstrated no significant difference between PSPG and MI. With PSPG, average individual deviation from neutral for the femoral component was significantly less (0.91i,° vs. 1.34i,°, p = 0.0005) and had fewer outliers >2i,° (4.9% vs. 19.6%, p = 0.017). Discussion: Improved coronal alignment in total knee arthroplasty (TKA) is associated with greater patient satisfaction, better functional scores and increased implant longevity [11,30,31,36]. Recently, preoperative three-dimensional imaging and custom manufacturing have enabled the development of patient-specific positioning guides (PSPG). Designed to improve consistency and efficiency, PSPG represents a paradigm shift away from intramedullary and extramedullary guides, or manual instrumentation (MI), and an evolution from intraoperative computer-assisted navigation (CAN). Even in the hands of experienced surgeons, MI frequently results in significant component angulation and mechanical axis malalignment [32]. Multiple studies support the restoration of a neutral axis as a critical factor in implant performance and potential longevity of total knee arthroplasty [2, 3, 5, 18, 41, 44]. Intraoperative CAN has been shown to improve precision and accuracy of alignment compared to MI with a reduction in the number of outliers (less than 3i,° varus/valgus) [32, 38] and the amount of blood loss [39], but is hindered by time-consuming landmark registration, increased operative length [7], greater cost, the risk for stress fracture, pin loosening, and a substantial learning curve [6, 22, 29, 43]. Patient-specific positioning guides, on the other hand, purportedly eliminate many of the disadvantages of CAN while still allowing the bone resections to match the measured overall mechanical axis. While accurate and precise alignment guides are potent tools in restoring the proper overall mechanical axis, they are not a substitute for careful preoperative planning, good clinical and intraoperative judgment, appropriate soft tissue balancing, and precise implantation technique. Nevertheless, patient-specific positioning guides can provide the first step in the right direction to a successful TKA. Conclusions: Patient-specific positioning guides can assist in restoration of the mechanical axis with reduction in outliers. Level of Evidence: Level III, retrospective case-control study

Improved Accuracy of Alignment With Patient-Specific Positioning Guides Compared with Manual Instrumentation in TKA

Optimization of surface roughness and cutting force during AA7039/Al2O3 metal matrix composites milling using neural networks and Taguchi method

http://www.ysxbcn.com/down/2014/09_en/09-p2805.pdf

Optimization of machining parameters in turning of Al−SiC−Gr hybrid metal matrix composites using grey-fuzzy algorithm

Management of early stages of osteonecrosis aims to prevent the collapse of the femoral head by attempts at restoring the vascularity of femoral head. Bone marrow-derived mononuclear cells with their angiogenic and osteogenic properties appear to have the potential to halt the disease process when injected intralesionally following core decompression. Forty patients (60 hips) with stage I, II or III (ARCO system) osteonecrosis of femoral head were treated by either core decompression and isolated mononuclear cells (group A) or core decompression and unprocessed bone marrow injection (group B). The patients were followed up clinically and radiologically for a minimum of 2 years. The functional outcome was assessed in terms of Harris hip score, and disease progression was assessed radiologically by comparing the preoperative and follow-up MRI at the end of 2 years. On 2-year follow-up, there was considerable improvement in the hip function as measured by the Harris hip score in both the groups (p = 0.031). On MRI, there was a decrease in the size of the lesion in group A (p = 0.03). Three of 30 hips (10.0 %) in group B required total hip replacement. Implantation of autologous bone marrow stem cells in avascular necrosis of femoral head is a safe and effective procedure and has better outcome than bone marrow for early stage of avascular necrosis of femoral head.

Intralesional autologous mesenchymal stem cells in management of osteonecrosis of femur: a preliminary study

Managing displaced intra-articular calcaneal fractures remains controversial. A prospective randomised trial was undertaken to compare open reduction and internal fixation (ORIF) with minimally invasive reduction and percutaneous fixation (MIRPF). Forty-five displaced intra-articular calcaneal fractures were randomised to undergo either ORIF (n = 23) or MIRPF (n = 22). Patients were followed up clinically and radiologically for a minimum of one year postoperatively. The primary outcome measure was wound-healing complication. Functional outcome was assessed using Creighton Nebraska Health Foundation (CNF) scale, and radiological outcome was assessed using plain radiographs and computed tomography (CT) scans. Of the 23 heels in the ORIF group, seven (30%) had wound-healing problems, compared with none in the MIRPF group (p = 0.005). There was no statistically significant difference in radiological outcomes between groups, as measured by Bohler’s angle, Gissane’s angle and Score Analysis of Verona (SAVE). Median time to return to work was two weeks earlier (p = 0.004), and the functional outcome score (CNF scale) at one year of follow-up was better (p = 0.013) following MIRPF compared with ORIF. MIRPF is associated with fewer wound-healing problems, better functional outcome and earlier return to work compared with ORIF.

Prospective randomized trial comparing open reduction and internal fixation with minimally invasive reduction and percutaneous fixation in managing displaced intra-articular calcaneal fractures

A prospective, randomised, controlled trial was performed to compare the outcome of treatment of unstable trochanteric fractures with either a short proximal femoral nail antirotation (PFNA) or dynamic hip screw (DHS). Eighty one patients with unstable fracture of the proximal part of the femur were randomised, at the time of admission, for fixation with either a short PFNA (n=42) or DHS (n= 39). The primary outcome measure was reoperation within the first postoperative year and mortality at the end of one year. Operative time, fluoroscopy time, blood loss, and any intra-operative complication were recorded for each patient. Clinical and radiological follow-up was undertaken for a minimum of 36 months. Any changes in the position of the implant or fixation failure were recorded. Hip range of motion, pain in the hip or thigh and return to work were used to compare the outcomes. There was no significant difference between 1 year mortality rates for the two groups. The mean operative time was significantly less in PFNA group (25 min) than in the DHS group (38 min). Patients treated with a PFNA experienced a shorter fluoroscopy time and less blood loss. Six patients in DHS group had implant failure while none experienced this in PFNA group. The PFNA group had a better functional outcome than the DHS group.

Outcome of short proximal femoral nail antirotation and dynamic hip screw for fixation of unstable trochanteric fractures. A randomised prospective comparative trial.

Pattern matching is a technique that can be used to identify or detect any anomaly packet from a sequential action. Injection attack is a method that can inject any kind of malicious string or anomaly string on the original string. Most of the pattern based techniques are used static analysis and patterns are generated from the attacked statements. In this paper, we proposed a detection and prevention technique for preventing SQL Injection Attack (SQLIA) using Aho-Corasick pattern matching algorithm. In this paper, we proposed an overview of the architecture. In the initial stage evaluation, we consider some sample of standard attack patterns and it shows that the proposed algorithm is works well against the SQL Injection Attack.

K. Marimuthu

Papers

Optimization of machining parameters in turning of Al−SiC−Gr hybrid metal matrix composites using grey-fuzzy algorithm

Intralesional autologous mesenchymal stem cells in management of osteonecrosis of femur: a preliminary study

Prospective randomized trial comparing open reduction and internal fixation with minimally invasive reduction and percutaneous fixation in managing displaced intra-articular calcaneal fractures

Outcome of short proximal femoral nail antirotation and dynamic hip screw for fixation of unstable trochanteric fractures. A randomised prospective comparative trial.

An efficient technique for preventing SQL injection attack using pattern matching algorithm