Introduction. The use of technology, such as navigation and robotic systems, may improve the accuracy of component positioning in total hip arthroplasty (THA) but its impact on patient reported outcomes measures (PROMs) remains unclear. This study aims to identify the association between intraoperative use of technology and patient reported outcomes measures (PROMs) in patients who underwent primary total hip arthroplasty (THA). Methods. We retrospectively reviewed patients who underwent primary THA between 2016 and 2020 and answered a post-operative PROM questionnaire. Patients were separated into three groups depending on the technology utilized intraoperatively: navigation, robotics, or no technology (i.e. manual THA. The Forgotten Joint Score (FJS-12) and Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) were collected at various time points (FJS: 3m, 1y, and 2y; HOOS, JR: pre-operatively, 3m, and 1y). Demographic differences were assessed with chi-square and ANOVA. Mean scores between all groups were compared using univariate ANCOVA, controlling for observed demographic differences. Results. Of the 1,960 cases included, 896 navigation, 135 robotics, and 929 manual. There was a significant statistical difference in one-year HOOS, JR scores (85.23 vs. 85.95 vs. 86.76; p=0.014) and two-year FJS-12 scores (64.72 vs. 73.35 vs. 74.63; p=0.004) between the three groups. However, they did not exceed the mean clinically important difference (MCID) at any time period. Short and long-term PROMs significantly differed between navigation and manually performed cases (FJS 3m: p=0.047; FJS 2y: p=0.001; HOOS, JR 1y: p=0.004). Two-year FJS-12 scores statistically differed between navigation and robotics (p=0.038). There was no statistical difference in either FJS-12 or HOOS, JR scores between robotics and manual THA groups at all time points (FJS 3m:p=0.076, 1y:p=0.225, 2y:p=0.793; HOOS, JR preop:p=0.872, 3m:p=0.644, 1y:p=0.531). Conclusion. Statistical differences observed between all modalities are not likely to be clinically meaningful with regards to early patient reported outcomes. While intraoperative use of technology may improve the accuracy of implant placement, these modalities have not necessarily translated into improved early reported functional outcomes

Introduction. There is debate regarding whether the use of computer-assisted technology, such as navigation and robotics, has any benefit on clinical or patient reported outcomes following total knee arthroplasty (TKA). This study aims to report on the association between intraoperative use of technology and outcomes in patients who underwent primary TKA. Methods. We retrospectively reviewed 7,096 patients who underwent primary TKA from 2016–2020. Patients were stratified depending on the technology utilized intraoperatively: navigation, robotics, or no technology. Patient demographics, clinical data, Forgotten Joint Score-12 (FJS), and Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) were collected at various time points up to 1-year follow-up. Demographic differences were assessed with chi-square and ANOVA tests. Clinical data and mean FJS and KOOS, JR scores were compared using univariate ANCOVA, controlling for demographic differences. Results. During the study period, 287 (4%) navigation, 367 (5%) robotics, and 6,442 (91%) manual cases were performed. Surgical time significantly differed between the three groups (113.33 vs. 117.44 vs. 102.11 respectively; p<0.001). Discharge disposition significantly differed between the three groups (p<0.001), with a greater percentage of patients who underwent manual TKA discharged to a skilled nursing facility (12% vs. 8% vs. 15%; p<0.001) than those who had intraoperative technology utilized. FJS scores did not statistically differ at 3-months (p=0.067) and 1-year (p=0.221) postoperatively. There was a significant statistical difference in three-month KOOS, JR scores (59.48 vs. 60.10 vs. 63.64; p=0.001); however, one-year scores did not statistically differ between the three groups (p=0.320). Mean improvement in KOOS, JR scores preoperatively to one-year postoperatively was significantly largest for the navigation group and least for robotics (27.12 vs. 23.78 vs. 25.42; p<0.001). Conclusion. This study demonstrates shorter mean operative time in cases with no utilization of technology and clinically similar patient reported outcome scores associated with TKAs performed between all modalities. While the use of intraoperative technology may aid surgeons, it has not currently translated to better short-term patient outcomes

Significance. Increasing health care costs are bankrupting the United States and other industrialized countries. To control and/or reduce costs in health care, hospitals, payers, and patients are turning to evidence-based meta-analyses and health economic analyses to identify medical treatments that provide value (value=outcome/cost). Objective: To determine if clinical outcome (patient reported outcomes) analyses or value/economic analyses are more likely to provide the evidence needed for adoption of new technologies in arthroplasty. Methods. A proprietary joint arthroplasty database of patient reported outcomes (PROs) was analyzed to determine the minimum clinically important differences (MCIDs) for PROs used for total knee replacement surgery. The PROs analyzed were: (1) European quality of life (EQ-5D); Oxford Knee Score (OKS); (3) Lower Extremity Activity Scale (LEAS); and (4) Likert Pain Scale (LPS). The MCID was calculated using a distribution method where the MCID equals one half the standard deviation of the score change, MCID = σΔ/2. For clinical meta-analyses, new technologies must demonstrate statistically significant better PROs and the difference must be greater than the MCID. For economic analyses, quality adjusted life years (QALYs) are used. For example, if a total knee replacement (TKR) improved a patient's health-related quality of life by 10% (0.10) and the assumed implant life is 15 years, the patient received 1.5 QALYs (0.10 × 15 years). If the total cost of care for the knee replacement surgery is $30,000, the cost per QALY is $20,000 ($30,000/1.5 QALYs). Results. The MCIDs for EQ-5D, OKS, LEAS, and LPS are 0.086%, 4.6 points, 1.6 points, and 1.3 points, respectively. The mean change (one-year post-operative EQ-5D minus pre-operative EQ-5D) for health-related quality of life is 15% (0.15). The average patient received 2.25 QALYs (0.15 × 15 years) from the surgery. The average cost per QALY is $13,333. However, if a new technology improves the mean health-related quality of life by 1% and the assumed implant life is 15 years, the patient receives 0.15 QALYs of improvement. With an average cost per QALY of $13,333, the new technology will be cost effective if the new technology cost is less than or equal to $2,000 (0.15 × $13,333) per patient. Conclusions. Achieving clinical superiority with new arthroplasty technology will be difficult because the minimum clinically important differences that need to be achieved are significant (EQ-5D 8.6%, OKS 4.6 points, LEAS 1.3 points, and LPS 1.3 points). However, small mean improvements in health-related quality of life (1%) can make the new technology cost effective. New technologies for arthroplasty surgery will increasingly need economic analyses to demonstrate cost effectiveness. Orthopaedic surgeons and manufacturers must collaborate to routinely collect health-related quality of life (EQ-5D) patient reported outcomes to provide a pathway for adoption of new innovative arthroplasty technologies

Introduction. Robotic-arm assisted knee arthroplasty (rKA) has been associated with improved clinical, radiographic, and patient-reported outcomes. There is a paucity of literature, however, addressing its cost effectiveness. In the context of an integrated health system with an insurance plan and single source comprehensive data warehouse for electronic health records and claims data, we present an evaluation of healthcare costs and utilization associated with manual knee arthroplasty (mKA) versus rKA. We also examine the influence of rKA technology on surgeons’ practice patterns. Methods. Practice patterns of KA were assessed 18 months before and after introduction of robotic technology in April 2018. For patients also insured through the system's health plan, inpatient costs (actual costs recorded by health system), 90-day postoperative costs (allowed amounts paid by insurance plan), and 90-day postoperative utilization (length of stay, home health care visits, rehabilitation visits) were compared between mKA and rKA patients, stratified by total (TKA) or unicompartmental (UKA) surgery. Linear regression modeling was used to compare outcomes between the two pairs of groups (mKA vs. rKA, for both UKA and TKA). Log-link function and gamma error distribution was used for costs. All analyses were done using SAS statistical software, with p<0.05 considered statistically significant. Results. Overall KA volume increased 21%, from 532 cases in the pre-rKA period to 644 post-rKA introduction, with UKA surgeries increasing from 38 to 97 (155%). Of these KAs, 218 patients were insured through our system's health plan (38 rUKAs, 9 mUKAs, 91 rTKAs, and 80 mTKAs), allowing precise insurance claims analysis for postoperative utilization and cost. Patients with rKA had significantly lower mean home health costs (-90% difference for UKA, −79% difference for TKA, p<0.02) and home rehab costs (-64% difference for UKA, −73% difference for TKA, p≤0.007) than mKA patients. No significant differences were observed in outpatient rehab (visits or costs), total rehab costs, or length of stay. Mean total postoperative costs were significantly lower for rUKA than mUKA (-47% difference, p=0.02) but similar for TKA (p>0.05). There were no significant differences in total inpatient costs between MAKO and non-MAKO patients. Conclusion. Robotic-arm assisted KA can allow for increased UKA volume and potential for substantial cost savings over the total episode of care by reducing postoperative utilization and costs

Purpose. South African arthroplasty surgeons commonly make use of new bearing surface technology. This new technology only has short term, industry funded clinical trials or simulator studies available to prove its performance and motivate its use. These products are being used despite the availability of conventional components with proven long term in vivo efficacy. In the light of the recent Du Puy ASR recall, which also showed initial good clinical results, we reviewed the available data on some of the new available bearing surface technology. Methods. We performed a literature search to identify the best available clinical data regarding duration of follow up and number of patients for a selection of new bearing surfaces and compared it to well known long term clinical follow up studies and joint registry data of conventional products. Results. New bearing surface technologies have no long term clinical supportive data. Short and medium term results are available, however these are limited and mainly industry funded. Simulator data constituts the bulk of research used as motivation for the introduction of new technologies. Conclusion. The currently available data on new bearing surface technology is not adequate to provide the arthroplasty surgeon with a confident opinion on long term safety and efficacy. Surgeons should be careful when recommending new products to their patients, who are usually well informed of new technology but often without the necessary insight. NO DISCLOSURES

Background. It is technically challenging to restore hip rotation center exactly in total hip arthroplasty (THA) for patients with end-stage osteoarthritis secondary to developmental dysplasia of the hip (DDH) due to the complicated acetabular morphology changes. In this study, we developed a new method to restore hip rotation center exactly and rapidly in THA with the assistance of three dimensional (3-D) printing technology. Methods. Seventeen patients (21 hips) with end-stage osteoarthritis secondary to DDH who underwent THA were included in this study. Simulated operations were performed on 3-D printed hip models for preoperative planning. The Harris fossa and acetabular notches were recognized and restored to locate acetabular center. The agreement on the size of acetabular cup and bone defect between simulated operations and actual operations were analyzed. Clinical and radiographic outcomes were recorded and evaluated. Results. The sizes of the acetabular cup of simulated operations on 3-D printing models showed a high rate of coincidence with the actual sizes in the operations(ICC value=0.930) There was no significant difference statistically between the sizes of bone defect in simulated operations and the actual sizes of bone defect in THA(t value=0.03 P value=0.97). The average Harris score of the patients was improved from (38.33±6.07) preoperatively to the last follow-up (88.61±3.44) postoperatively. The mean vertical and horizontal distances of hip rotation center on the pelvic radiographs were restored to (15.12 ± 1.25 mm and (32.49±2.83) mm respectively. No case presented dislocation or radiological signs of loosening until last follow-up. Conclusions. The application of 3-D printing technology facilitates orthopedists to recognize the morphology of Harris fossa and acetabular notches, locate the acetabular center and restore the hip rotation center rapidly and accurately

Background of Study. Identification of the exact make and model of an orthopaedic implant prior to a revision surgery can be challenging depending upon the surgeon's experience and available knowledge base about the available implants. The current identification procedure is manual and time consuming as the surgeon may have to do a comprehensive search within an online database of radiographs of an implant to make a visual match. There is further time lapse in contacting that particular implant manufacturer to confirm the make and model of the implant and then order the whole inventory for the revision surgery. This leads to delay in treatment thus requiring extra hospital bed occupancy. Materials and Methods. We have analysed image recognition techniques currently in use for image recognition to understand the underlying technologies based on an interface commonly known as Application Programming interface (API). These API's specifies how the software components of the proposed application interact with each other. The objective of this study is to leverage one or a combination of API's to design a fully functional application in the initial phase and that can help recognize the implant accurately from a large database of radiographs and then develop a specialized and advanced API/Technology in the implant identification application. Results. Our study takes into account the existent technologies such as Facebook, Pictoria, Imagga, Google images. We found that there is an API currently available that can be directly applied to build an implant recognition system. However, commonly known Facebook's image tagging algorithms to store unique information with each image is the starting point to help build an intelligent system that in combination with image processing and development of a custom implant recognition API. Conclusion. There is an urgent need to have a robust and accurate system for identification of orthopaedic implants. Revision surgeries may need to be carried out by hospitals without access to index surgery operating notes. Patients may approach the most convenient not necessarily the same surgeon for a revision surgery. The dependency upon surgeon's experience, hospitals facilities and archiving of records can be avoided with the use of a single application that allows multiple manufacturers to contribute to a database of catalogue of their products

INTRODUCTION. Measurement of range of motion is a critical item of any knee scoring system. Conventional measurements used in the clinical settings are not as precise as required. Smartphone technology using either inclinometer application or photographic technology may be more precise with virtually no additional cost when compared to more sophisticated techniques such as gait analysis or image analysis. No comparative analysis between these two techniques has been previously performed. The goal of the study was to compare these two technologies to the navigated measurement considered as the gold standard. MATERIAL. Ten patients were consecutively included. Inclusion criterion was implantation of a TKA with a navigation system. METHODS. Two free angle measurement applications were downloaded to the Smartphone: one using inclinometer technology, the other using camera technology. After navigation assisted TKA and just before wound closure, the operated knee was positioned at full extension, 30±2°, 60±2°, 90±2° and 120±2° according to the navigated measurement. At each step, the knee flexion angle was measured with both Smartphone applications: inclinometer application (figure 1) and camera application (figure 2). For each of the ten patients, 5 navigated, 5 inclinometer and 5 camera measurements were obtained for each patient, giving three sets of 50 repeat measurements. The sample size was calculated to get a significance level of 0.05 and a power of 0.8 to detect a 10° difference. The difference between the three sets of measurements was analyzed with an ANOVA test for repeat measurements, with post-hoc comparisons with a paired Wilcoxon test. The correlation between the three sets of measurements was analyzed with a Kendall test, with post-hoc comparisons with a Spearman test. All tests were performed at a 0.05 level of significance, and post-hoc comparisons were performed at a 0.01 level of significance. RESULTS. The mean paired difference between navigated and camera measurements was 0.7° (SD 1.5°), with one difference greater than 3°. The mean paired difference between navigated and inclinometer measurements was 7.5° (SD 5.3°), with 16 differences greater than 10°. The mean paired difference between inclinometer and camera measurements was −6.8° (SD5.2°), with 7 differences greater than 10°. The ANOVA test for repeat measurements showed a significant difference between the three sets of measurements (p<0.001). The results of post-hoc paired comparisons with the Wilcoxon test are reported in table 2. The Kendall test showed that the distribution of the three sets of measurements was no different. The post-hoc paired correlations with the Spearman test showed a good coherence between all pairs of measurements (R² between 0.02 and 0.12). No pre-operative criteria showed a significant influence on the differences observed. DISCUSSION. Measuring the knee flexion angle with the camera of a smartphone is effective in a routine clinical practice. Accuracy can be better than other conventional measurement techniques. All applications of a smartphone do not have the same precision and must be validated before clinical use. CONCLUSION. Smartphone technology enables a more accurate assessment of the knee range of motion after TKA than conventional measurement techniques. To view tables/figures, please contact authors directly

Shoulder arthroplasty has experienced exponential growth in the past 10–15 years, largely due to improvements in anatomical design, increased application of technology to address various clinical pathology, and improved access to experienced shoulder surgeons. Glenohumeral arthritis has historically been the most common indication for a shoulder replacement, and glenoid wear has been the main concern with regards to longevity of the prosthesis. Attempts to improve glenoid components involve alterations in peg or keel configuration, as well as the introduction of metal backed constructs. Early experience with metal backed components led to very poor results with often catastrophic loosening and destruction of glenoid bone. Proximal humerus fractures are another common indication for a shoulder arthroplasty, and in these cases, tuberosity fixation and healing are the challenge precluding a consistently successful result. More recently, base plate fixation in the setting of a reverse shoulder arthroplasty has come to the forefront as a significant factor. Trabecular metal technology has emerged as a compelling method of enabling powerful bone ingrowth to the surfaces of arthroplasty components. Trabecular metal is composed of tantalum. It is used to form a carbon scaffold which has a modulus between that of cancellous and cortical bone, thus has some flexibility when made into an independent construct. Vapor deposition onto arthroplasty surfaces provides a bone ingrowth surface. There is interest in utilizing trabecular metal for glenoid and tuberosity fixation in particular. Trabecular metal proximal coated stems provide an ingrowth surface for tuberosity fixation in the setting of proximal humerus fractures. Long term results are still pending. Because the metal is much less stiff then other metals, trabecular metal has recently been used along the back of polyethylene glenoids. The original design had a problem with fracture at the base of the pegs. A redesigned component instituting a cruciate design was implemented, and is currently available on a limited release basis with promising early results. The use of trabecular metal on the deep surface of the reverse arthroplasty baseplate and the proximal aspect of the reverse stem has led to successful fixation, allowing cementless fixation of both the humeral and glenoid components. Learning objectives of this presentation include:. Understand the mechanical characteristics of trabecular metal and its bone ingrowth characteristics. Familiarize with currently available prosthetics incorporating trabecular metal technology. Case presentations utilizing trabecular metal coated components

The plasma spray(TPS) has come to be accepted as one of the more reliable methods of porous coating of prosthesis, it is not without some technical limitations, especially with regard to precise modulation of pore size, porosity, and roughness. However, the plasma spray(TPS) not often but seriously faces problems such as bead detachment related poor osteointegration, weakness of metal strength and high manufacturing costs in addition to its various technical limitations. Currently, there has been much research into developing a more economical and effective method for porous coating of the prosthesis. In light of such demand, 3D Printing with DMT Technology has been introduced into the field of surface treatment of prosthesis with promising expectations. DMT technology -an additive fabrication process that uses high-power laser and various metal powders in order to produce fully dense and geometrically complex metal components, molds, and dies directly from digital CAD model data of 3D subjects aims to help overcome many of the problems associated with plasma spray and thereby open a new chapter of endless possibilities for coating technology. In this study, the porous coating specimen using 3-D DMT metal printing was characterized morphologically as well as biomechanically, in terms of 1) pore size 2) porosity 3) tensile strength 4) shear strength 5) roughness respectively. The biological cyto-compatibility was evaluated by culturing human osteoblast-like cells(Saos-2: ATCC HTB85) on the surface of round discs with porous coating to demonstrate the biological influence on the porosity of the specimens with different surface treatment for comparative analysis. The evaluation was accompanied by assessment of cell proliferation and morphology with arrangement of actin filament and expression of adhesion molecule with α. v. β. 3. integrin. While 3-D DMT coating specimen showed relatively regular porosity in the range of 150–500µm with the increase of porosity about 83%, the mechanical behavior remarkably improved, compared to TPS: shear strength 13%, fatigue failure 30%, roughness 16%, respectively. Also worth noting, the tensile strength was unable to be measured because the glue for test had fallen off. (Fig. 1) There is no transitional zone underneath the porous coating layer.(Fig. 2) From the aspect of biocompatibility, 3-D coating showed better cell attachment, spreading of cytoskeleton, cell proliferation, and expression of osteogenic markers than TPS, even if not significantly.(Fig. 3) Additionally, cell migration assay was performed with double chamber study, and gene expression was evaluated by measuring alkaline phosphatase(ALP) levels and analyzing mRNA expression for ostepontin(OPG) and osteocalcin(OC). In conclusion, the study reinforces the popular stance that the implementation of 3-D DMT could open up new possibilities for coating technology and form a new chapter in the history of prosthesis development

Biological fixation of arthroplasty devices through osseointegration via ingrowth or ongrowth can be achieved with a numerous surface treatments and technologies. Surface roughness and topography have evolved to include sintered bead, calcium phosphate coatings and more recently additive manufacturing techniques. Regardless of the technique employed, the clinical goal has always been directed at improving osseointegration and achieve rapid, stable and long-term implant fixation without compromising the mechanical properties of the device. Pre-clinical models provide insight into the in-vivo efficacy. The in vivo results of a wide range of technologies over the past 20 years have been examined by our laboratory using an adult ovine cortical and cancellous implantation model. This paper will present a twenty year experience of pre-clinical evaluation of bone ingrowth and ongrowth surfaces used for arthroplasty device fixation. The endpoints as well as understanding of the dynamic nature of the bone-implant interface continues to evolve as advanced manufacturing moves forward and the demands on the interface due to patient and surgeon expectations increase

Rural surgical practice in Australia provides a unique environment to the Orthopaedic Surgeon. Whilst most of the work load mimics that of city practice, the rural surgeon has little choice but to master a broad schema of surgical skills, and keeping up with the current literature and techniques can be challenging. At our public hospital over the last audited twelve month period, 108 primary total knee replacements were performed by 4 surgeons out of 236 joint replacements including revision surgeries. At the Private hospital a total of 215 joint replacements were performed in the same period including revision surgeries, of which 127 were knee arthroplasties. It is recognised that the incidence of complications from arthroplasty can be increased in low volume joint replacement surgeons. This centre is a mid volume centre, but rural and generally underfunded. In light of this, it is not unreasonable to look at techniques or evolving technologies that may improve the ability of an individual surgeon to position a joint replacement in an optimal position and with economic consideration. Conventional navigation has a number of factors associated with it that may make its use in a rural centre less attractive. These include capital cost of both hardware and software; Most rural centres do not have the ability to purchase the hardware and thus the issue of transporting hard ware on site, and representative support, may all be issues. The potential benefit of patient specific implants [PSI] may thus be two-fold in this setting. The surgeon and the patient benefit from the technology, but the technology does not need to be transported to the site. As a result of these considerations, a single surgeon in a rural centre, commenced using PSI's after gaining initial experience with the implant using traditional techniques. This early study looks at this experience and attempts to quantify some of the issues around this technology

The use of 3D imaging methodologies in orthopaedics has allowed the introduction of new technologies, such as the design of patient-specific implants or surgical instrumentation. This has introduced the need for high accuracy, in addition to a correct diagnosis. Until recently, little was known about the accuracy of MR imaging to reconstruct 3D models of the skeletal anatomy. This study was conducted to quantify the accuracy of MRI-based segmentation of the knee joint. Nine knees of unfixed human cadavers were used to compare the accuracy of MR imaging to an optical scan. MR images of the specimens were obtained with a 1.5T clinical MRI scanner (GE Signa HDxt), using a slice thickness of 2 mm and a pixel size of 0.39 mm × 0.39 mm. Manual segmentation of the images was done using Mimics® (Materialise NV, Leuven, Belgium). The specimens were cleaned using an acetone treatment to remove soft-tissue but to keep the cartilage intact. The cleaned bones were optically scanned using a white-light optical scanner (ATOS II by GOM mbH, Braunschweig, Germany) having a resolution of 1.2 million pixels per measuring volume, yielding an accuracy of 0.02 mm. The optical scan of each bone reflects the actual dimensions of the bone and is considered as a ground truth measurement. First, a registration of the optical scan and the MRI-based 3D reconstruction was performed. Then, the optical scan was compared to the 3D model of the bone by calculating the distance of the vertices of the optical scan to the reconstructed 3D object. Comparison of the 3D reconstruction using MRI images and the optical scans resulted in an average absolute error of 0.67 mm (± 0.52 mm standard deviation) for segmentation of the cartilage surface, with an RMS value of circa twice the pixel size. Segmenting the bone surface resulted in an average absolute error of 0.42 mm (± 0.38 mm standard deviation) and an RMS error of 1.5 times the pixel size. This accuracy is higher than reported previously by White, who compared MRI and CT imaging by looking at the positioning of landmarks on 3D printed models of the segmented images using a calliper [White, 2008]. They reported an average accuracy of 2.15 mm (± 2.44 mm) on bone using MRI images. In comparison, Rathnayaka compared both CT- and MRI-based 3D models to measurements of the real bone using a mechanical contact scanner [Rathnayaka, 2012]. They listed an accuracy of 0.23 mm for MRI segmentation using five ovine limbs. This study is one of the first to report on the segmentation accuracy of MRI technology on knee cartilage, using human specimens and a clinical scanning protocol. The results found for both bone and cartilage segmentation demonstrate the feasibility of accurate 3D reconstructions of the knee using MRI technology

Introduction. The most common bearing couple used in total knee arthroplasty (TKA) is ultra-high molecular weight polyethylene (UHMWPE) articulating against a CoCrMo alloy femoral component. Although this couple has demonstrated good clinical results, UHMWPE wear has been identified as one of the principal causes for long-term failure of total knee joint replacements. 1. indicating a need for improvements in TKA bearings technology. The wear resistance of UHMWPE can be improved by radiation crosslinking; however, in order to get the full benefit of this improved wear resistance, an abrasion resistant ceramic counterface is necessary. 2. Since the radiation crosslinking degrades mechanical properties, it is also important to have an optimized radiation dose and subsequent processing. The purpose of this study was to evaluate the long-term wear performance of VERILAST Technology comprising two advanced bearing technologies, abrasion resistant OXINIUM femoral components (OxZr). 3-4. and wear/strength optimized 7.5 Mrad crosslinked polyethylene (7.5-XLPE). 5. Materials and Methods. Three component assemblies of LEGION(tm) cruciate retaining (CR) OxZr femoral components, 7.5-XLPE tibial inserts were tested on an AMTI knee simulator under displacement control at 1 Hz frequency as described previously. 2. The tibial inserts were manufactured from compression molded GUR 1020 UHMWPE, radiation crosslinked to 7.5 Mrad dose, remelted to extinguish free radicals, and sterilized by EtO. The wear test was conducted for 45 Mcycle, which was considered to be a conservative estimate for the amount of cycles that would occur during 30 years of typical in-vivo use based on the relationship between patient age and the number of loading cycles as reported in the literature. 6-8. Results. The predominant wear feature on the 7.5-XLPE inserts was burnishing. There were no signs of fatigue wear or delamination. The mean volumetric wear rate (± SD) of the 7.5-XLPE inserts articulating against OxZr femoral components for 45 Mcycle was 0.58±0.17 mm. 3. /Mcycle. In a previous wear test under substantially identical conditions for 5 Mcycle simulating approximately 3 years of use, the mean volumetric wear rate of CoCr and virgin UHMWPE (CPE) couples was 23.4±2.4 mm. 3. /Mcycle. 2. The mean volumetric wear rate of the OxZr/7.5-XLPE couples was approximately 98% lower compared to the CoCr/CPE couples (p<0.01). After simulating 3 years of use, the mean volumetric wear of OxZr/7.5-XLPE couples (2.67 mm. 3. ) was approximately 98% lower than CoCr/CPE couples (120.42 mm. 3. ) (Figure 1). Furthermore, after simulating 30 years of use, the mean volumetric wear of OxZr/7.5-XLPE couples (22.78mm. 3. ) was approximately 81% lower than the CoCr/CPE couples after simulating 3 years of use (120.42 mm. 3. ) (Figure 2). Discussion. This study demonstrates that coupling OxZr femoral components with 7.5-XLPE inserts results in a TKA bearing combination that provides and maintains significantly lower, long-term wear performance

Introduction:. Cam type femoroacetabular impingement (FAI) may lead to osteoarthritis (OA)[1]. In 2D studies, an alpha angle greater than 55° was considered abnormal however limitations of 2D alpha angle measurement have led to the development of 3D methods [2–4]. Failure to completely address the bony impingement lesions during surgery has been the most common reason for unsuccessful hip arthroscopy surgery [5]. Robotic technology has facilitated more accurate surgery in comparison to the conventional means. In this study we aim to assess the potential application of robotic technology in dealing with this technically challenging procedure of cam sculpting surgery. Methods:. CT scans of three patients' hips with severe cam deformity (A, B and C models) were obtained and used to construct 3D dry bone models. A 3D surgical plan was made in custom written software. Each 3D plan was imported into the Acrobot Sculptor robot and bone resection was carried out. In total, 42 femoral models were sculpted (14/subset), thirty of which were performed by a single operator and the remaining 12 femurs were resected by two other operators. CT of the pre/post resected specimens was segmented and a 3D alpha angle and head neck ratios were measured [3–4] and compared using Mann-Whitney U test. Coefficient of variation (CV) was used to determine the degree of variation between the mean and maximum observed alpha angles for inter and intra observer repeatability. Results:. The maximal alpha angle in cam A, B and C (90.8°, 91.3° and 87.1°). There was significant reduction (p < 0.001) in maximum alpha angles post-operatively within all three models when compared to original model (Figure 1). The HNRs for cam A, B and C prior to surgery were found to be 3.2, 3.4 and 3.1 respectively that were reduced to a mean of 3.0 ± 0.1, 3.1 ± 0.1 and 3.1 ± 0.0, following resection surgery. The results of the intra and inter-observer repeatability study found good reproducibility (CV<10%) of the maximum and mean alpha angles between the 12 resected femurs. Discussion:. In this study we evaluated the use of robotic system to perform cam correction surgery by evaluating the 3D morphology of head/neck prior to and post surgery. With existing surgical options there is a potential for under or over-resection of the cam lesion, which runs the risk of the need for further surgery or rarely neck fracture and dislocation. Based on the calculated alpha angles and HNRs we have proved that we have successfully performed the surgery by avoiding under and over resection respectively. Amore accurate bony resection performed here may minimize the complications due to over and under resection and hence will decrease the burden on the health service

Background. Dislocation is a common complication after proximal and total femur prosthesis reconstruction for primary bone sarcoma patients. Expandable prosthesis in children puts an additional challenge due to the lengthening process. Hip stability is impaired due to multiple factors: Resection of the hip stabilizers as part of the sarcoma resection: forces acts on the hip during the lengthening; and mismatch of native growing acetabulum to the metal femoral head. Surgical solutions described in literature are various with reported low rates of success. Objective. Assess a novel 3D surgical planning technology by use of 3D models (computerized and physical), 3D planning, and Patient Specific Instruments (PSI) in supporting correction of young children suffering from hip instability after expandable prosthesis reconstruction following proximal femur resection. This innovative technology creates a new dimension of visualization and customization, and could improve understanding of this complex problem and facilitate the surgical decision making and procedure. Method. Two children, both patients with Ewing Sarcoma of the left proximal femur stage-IIB, ages 3/5 years at diagnosis, were treated with conventional chemotherapy followed by proximal femur resection. Both were reconstructed with expandable prosthesis (one at resection and other 4 years after resection). Hip migration developed gradually during lengthening process in the 24m follow up period. 3D software (Mimics, Materialise, Belgium) were used to make computerized 3D models of patients' pelvises. These were used to 3D print 1:1 physical models. Custom 3D planning software (MSk Lab, Imperial College London) allowed surgeons visualizing the anatomical status and assess of problem severity. Thereafter, osteotomies planes and the desired position of acetabular roof after reduction of hip joint were planned by the surgeons. These plans were used to generate 3D printed PSIs to guide the osteotomies during shelf and triple osteotomy surgeries. Accuracy of planning and PSIs were verified with fluoroscopy and post-op X-rays, by comparing cutting planes and post-op position of the acetabulum. Results. Surgeons reported excellent experience with the 3D models (computerized and physical). It helped them in the decision process with an improved understanding of the relationship between prosthesis head and acetabulum, a clear view of the osteophytes and bone formation surrounding the pseudoacetabulum, and osteophytes inside the native acetabulum. These osteophytes were not immediately visible on 2D CT imaging slices. Surgeons reported a good fit and PSIs' simplicity of use. The hip stability was satisfactory during surgery and in the immediate post-op period. X-ray showed a good and centered position of the hip and good levels of the osteotomies. Conclusions. 3D surgical planning and 3D printing was found to be very effective in assisting surgeons facing complex problems. In these particular cases neither CT nor MRI were able to visualize all bony formation and entrapment of prosthesis in the pseudoacetabulum. 3D visualisation can be very helpful for surgical treatment decisions, and by planning and executing surgery with the guidance of PSIs, surgeons can improve their surgical results. We believe that 3D technology and its advantages, can improve success rates of hip stability in this unique cohort of patients

This study evaluates high power low frequency ultrasound transmitted via a flat vibrating probe tip as an alternative technology for meniscal debridement in the knee. A limitation of this technology is thermal damage in residual meniscal tissue. To compare tissue removal rate and thermal damage for a radiofrequency ablation device and an experimental ultrasound ablation device. Twelve bovine meniscal specimens were treated in an identical fashion with (a) a 3.75mm 50° bipolar radiofrequency wand, Arthrocare Super Multivac 50 Arthrowand (Arthrocare Corporation, Sunnyvale, CA), operated in a free-hand manner in accordance with manufacturers instructions (n=6), and (b) an experimental flat-tipped 3mm 20kHz ultrasound probe, suspended vertically in a 500N force-controlled experimental rig (n=6). Tissue removal rate (TRR), zone of thermal necrosis and zone of thermal alteration were calculated. Histological sections were prepared for each sample (H&E). Independent samples t-test was used to compare TRR, zone of thermal necrosis and zone of thermal alteration. Statistical analysis was performed using PASW Statistics (v.18, IBM SPSS Statistics, Chicago, IL, U.S.A.). The mean TRR for meniscal debridement by the radiofrequency device was 5.59±1.1mg/s. This compared with a mean TRR of 4.74±1.4mg/s for debridement with the ultrasound device at settings (p=0.259, NS). Mean depth of tissue removal using the radiofrequency device was 2.21±0.26mm compared to 3.75±0.25mm (p< 0.001, ?. 2. =0.09). Using the radiofrequency device, the mean depth of zone of thermal alteration was 1282±436µm, compared with 710±251µm for the force-controlled ultrasound device (p=0.29, ?. 2. =0.42). For the radiofrequency device, the mean depth of zone of thermal necrosis was 64±41µm versus 97±44µm for the ultrasound device (p=0.239, NS). We observed a trend towards an increased zone of thermal necrosis and a reduced zone of thermal alteration for the ultrasound device, when compared with the radiofrequency device. Ultrasonic debridement shows comparable thermal damage to existing radiofrequency meniscal debridement technology

Acetabular cup placement in total hip replacement surgery is often difficult to assess, especially in the lateral position and using the posterior approach. On table control X-Rays are not always accessible, especially in the government sector. Conventional techniques and computer assisted surgery (CAS), are currently the two most popular methods for proper placement of the acetabular cup in Lewinnek's safe zone of orientation (anteversion 15°–10° and lateral inclination 40°±10°). We developed a simple way to get accurate cup placement using Smartphone technology. Methods:. A spirit level application was downloaded to the Smartphone. The acetabulum inclination was measured on the pre-operative X-Rays. The phone is placed in a sterile bag and then used intra-operatively, to measure and set our acetabular cup orientation to our pre-operative measurements. The inclination level was measured before and after final placement of the acetabular cup. This was compared to the acetabular cup inclination in our post-operative X-Rays. Results:. In our series of 50 cup placements we found high accuracy. The results show less than 5° deviation between our pre-, intra- and post-operative measurements. Conclusions:. Smartphone technology proves to be good alternative to conventional methods and CAS, to improve Acetabular Cup placement in Total Hip Arthroplasty

Introduction. 3-D Printing with direct metal tooling (DMT) technology was innovatively introduced in the field of surface treatment of prosthesis to improve, moreover to overcome the problems of plasma spray, hopefully resulting in opening the possibility of another page of coating technology. We presumed such modification on the surface of Co-Cr alloy by DMT would improve the ability of Co-Cr alloys to osseointegrate. Method. We compared the in vitro and in vivo ability of cells to adhere to DMT coated Co-Cr alloy to that of two different types of surface modifications: machined and plasma spray(TPS). We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines of human were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and avb3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups. Results. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the DMT group increased in comparison to those in the machined and TPS groups. Cell proliferation, alkaline phosphatase activity, migration, and adhesion were increased in DMT group compared to the two other groups. Human Osteoblast cells on DMT-coated surface were strongly adhered, and proliferated well compared to those on the other surfaces. Discussion. The surface modifications of DMT coating enhanced the biocompatibility (proliferation and migration of osteoblastlike cells) of Co-Cr alloy. This process is not unique to Co-Cr alloy; it can be applied to many metals to improve their biocompatibility, thus allowing a broad range of materials to be used for cementless implants

Computer-assisted techniques in total knee replacement (TKR) have been introduced to improve bone cuts execution and relevant prosthesis components positioning. Although these have resulted in good surgical outcomes when compared to the conventional TKR technique, the surgical time increase and the use of additional invasive devices remain still critical. In order to cope with these issues, a new technology in TKR has been introduced also for positioning prosthetic components according to the natural lower-limb alignment. This technique is based on custom-fit cutting block derived from patient-specific lower-limb scan acquisition. The purpose of this study is to assess the accuracy of the custom-fit technology by means of a knee surgical navigation system, here used only as measurement system, and post-operative radiographic evaluations. Particularly, the performances of two different custom-fit cutting blocks realized from as many scan acquisitions have been here reported. Thirty patients affected by primary knee osteoarthritis were enrolled in this study. Fifteen patients were implanted with GMK® (Medacta-International, Castel San Pietro, CH) and as many patients with Journey® (Smith&Nephew, London, UK). Both TKR designs were implanted by using custom-fit blocks for bone cut executions provided by the same TKR manufacturers according to a pre-operative web planning approved by the surgeon. Particularly, the cutting block for the former design was built from CT scan acquisition of the hip, knee and ankle, whereas that for the latter design from MRI scans acquisition of the knee and X-ray lower-limb overview. A knee surgical navigation system (Stryker®-Leibinger, Freiburg, Germany) was used for recording intra-operative alignment of bone cuts as performed by means of the custom-fit cutting blocks and relevant component positioning. Prosthetic components alignments were also assessed post-operatively on X-ray images according to a shape-matching technique. The accuracy of the custom-fit blocks was evaluated through the comparison between pre-operative planning, and intra/post-operative data. Discrepancies above 3° and millimeters were considered as outliers. Within the patient cohort, nine cases were fully analyzed at the moment and here reported. Over them and except for one case, the discrepancy between pre-operative planned femoral/tibial resection level on the frontal plane and the corresponding measured intra-operatively was within 3 mm, being 5 mm in the worse case. Two outliers were observed for the corresponding femoral/tibial cut rotational alignment. Particularly, in one patient, the discrepancy in femoral cut alignment was of 8° in flexion and 6° in external rotation; in another patient this was of 4° in extension and 4° in external rotation in the femoral and tibial cut alignment, respectively. Post-operative radiographs evaluations for the final prosthetic components revealed that femoral/tibial alignment were within 3° in all cases, except for those patients that were already outliers. These preliminary results reveal the efficacy of the custom-fit cutting block for TKR. These were generally fitted properly and final prosthetic components were accurately placed, although some discrepancies were observed. This new technology seems to be a valid alternative to conventional and computer-assisted techniques. More consistent conclusions can be deduced after final evaluation of all patients