Surgical factors play a critical role in predicting functional outcomes using machine learning in robotic-assisted total knee arthroplasty.

PURPOSE: Predictive models help determine predictive factors necessary to improve functional outcomes after total knee arthroplasty (TKA). However, no study has assessed predictive models for functional outcomes after TKA based on the new concepts of personalised surgery and new technologies. This study aimed to develop and evaluate predictive modelling approaches to predict the achievement of minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) 1 year after TKA. METHODS: Four hundred thirty robotic-assisted TKAs were analysed in this retrospective study. The mean age was 67.9 ± 7.9 years; the mean body mass index (BMI) was 32.0 ± 6.8 kg/m2. The following PROMs were collected preoperatively and 1-year postoperatively: knee injury and osteoarthritis outcome score for joint replacement, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) Function, WOMAC Pain. Demographic data, preoperative CT scan, implant size, implant position on the robotic system and characteristics of the joint replacement procedure were selected as predictive variables. Four machine learning algorithms were trained to predict the MCID status at 1-year post-TKA for each PROM survey. 'No MCID' was chosen as the target. Models were evaluated by class discrimination (F1-score) and area under the receiver operating characteristic curve (ROC-AUC). RESULTS: The best-performing model was ridge logistic regression for WOMAC Function (area under the curve [AUC] = 0.80, F1 = 0.48, sensitivity = 0.79, specificity = 0.62). Variables most strongly contributing to not achieving MCID status were preoperative PROMs, high BMI and femoral resection depth (posterior and distal), supporting functional positioning principles. Conversely, variables contributing to a positive outcome (achieving MCID) were medial/lateral alignment of the tibial component, whether the procedure was an outpatient surgery and whether the patient received managed Medicare insurance. CONCLUSION: The most predictive variables included preoperative PROMs, BMI and surgical planning. The surgical predictive variables were valgus femoral alignment and femoral rotation, reflecting the benefits of personalised surgery. Including surgical variables in predictive models for functional outcomes after TKA should guide clinical and surgical decision-making for every patient. LEVEL OF EVIDENCE: Level III.

Characterizing Osteophyte Formation in Knee Osteoarthritis: Application of Machine Learning Quantification of a Computerized Tomography Cohort: Implications for Treatment.

BACKGROUND: Osteophytes are commonly used to diagnose and guide knee osteoarthritis (OA) treatment, but their causes are unclear. Although they are not typically the focus of knee arthroplasty surgeons, they can predict case difficulty and length. Furthermore, their extent and location may yield much information about the knee joint status. The aims of this computed tomography-based study in patients awaiting total or partial knee arthroplasty were to: (1) measure osteophyte volume in anatomical subregions and relative change as total volume increases; (2) determine whether medial and/or lateral OA affects osteophyte distribution; and (3) explore relationships between osteophytes and OA severity. METHODS: Data were obtained from 4,928 computed tomography scans. Machine-learning-based imaging analyses enabled osteophyte segmentation and quantification, divided into anatomical regions. Mean three-dimensional joint space narrowing was assessed in medial and lateral compartments. A Bayesian model assessed the uniformity of osteophyte distribution. We correlated femoral osteophyte volumes with B-scores, a validated OA status measure. RESULTS: Total tibial (25%) and femoral osteophyte volumes (75%) within each knee correlated strongly (R2 = 0.85). Medial osteophytes (65.3%) were larger than lateral osteophytes (34.6%), with similar proportions in both the femur and tibia. Osteophyte growth was found in all compartments, and as total osteophyte volume increased, the relative distribution of osteophytes between compartments did not markedly change. No evidence of variation was found in the regional distribution of osteophyte volume between knees with medial, lateral, both, or no three-dimensional joint space narrowing in the femur or tibia. There was a direct relationship between osteophyte volume and OA severity. CONCLUSIONS: Osteophyte volume increased in both medial and lateral compartments proportionally with total osteophyte volume, regardless of OA location. The peripheral position of femoral osteophytes does not appear to contribute to load-bearing. This suggests that osteophytic growth represents a 'whole-knee'/global response. This work may have broad applications for knee OA, both surgically and nonoperatively.

Evaluation of an Initial Robotic-Assisted Direct Anterior Approach Cohort Receiving a New Short Metaphyseal Filling Collared Femoral Implant.

BACKGROUND: Shorter, metaphyseal-filling collared stems have become popular with the direct anterior approach (DAA), based on their ease of broaching and insertion through less invasive surgical exposures. To aid with the DAA, robotic-assisted technology provides three-dimensional computed tomography (CT) preoperative planning and intraoperative guidance to accurately assess stem version. With other femoral stems, this has been shown to provide more accurate implant planning and improved patient outcomes. The purpose of this study was to understand femoral stem placement predictability and patient outcomes for a newly designed metaphyseal-filling collared stem system through a DAA in combination with a robotic-assisted system during a single surgeon's initial cases. MATERIALS AND METHODS: A single high-volume surgeon, experienced with robotic-assisted DAA total hip arthroplasty (THA), adopted the use of a metaphyseal-filling collared stem. Intraoperative data and patient outcomes up to six months postoperative were collected prospectively during the surgeon's first 123 cases. Student's t-tests (α=0.05) were used for statistical comparisons. Intraoperative and radiographic assessments were performed for all 123 cases. RESULTS: The estimated version with neck-cut view of the robotic-assisted system was 13.81 ± 3.81°. The final version measurement captured with the robotic-assisted system was 16.56 ± 6.61°. The difference between the estimated version and robotic-assisted measured version was, on average, 2.68 ± 5.7° (p<0.001). The femoral stem sat at the level of the calcar in all but five cases. There were no intraoperative or postoperative periprosthetic fractures. Patients reported significant improvements in reduced Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), Patient-Reported Outcomes Measurement Information System (PROMIS 10), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores throughout their six-month recovery process with no patients reporting a periprosthetic joint infection, fracture, or dislocation. CONCLUSION: The use of a metaphyseal-filling collared stem with robotic-assisted DAA resulted in adequate stem version when assessed visually and with CT scan assessments. Version estimation values were improved upon over visual assessments when using the robotic system that maps out the proximal femur and the improvement was also demonstrated when compared to the prior literature. This may also be related to the stem's collar providing a visual guide during stem placement posterior fill of this triple-tapered stem design. Although further follow up is needed to assess longer-term outcomes, at six months postoperatively, patients had significant improvements in patient-reported outcomes with all patients reporting minimal to no restrictions with their THA.

True Confessions of Neutral Mechanical Disciple-How I Learned to Love a Patient-Specific Target.

INTRODUCTION: Classical neutral mechanical alignment in total knee arthroplasty (TKA) has been a standard paradigm, while more recently, other alignment schemas, such as kinematic, individualized, and functional, have been explored. This study aimed to investigate the effect of three-dimensional (3D) computed tomography (CT)-based surgical robotics inputs on a classically trained surgeon's TKA component positions and alignment targets over time. MATERIALS AND METHODS: Data from 1,394 consecutive robotically-assisted TKAs by a single surgeon from 2016 to 2020 were analyzed. Metrics collected included pre-balance planned implant component positions, final planned implant component positions after soft tissue balancing, and constitutional alignment from CT scans. Joint line obliquity was plotted against the arithmetic hip-knee angle (aHKA) using coronal plane alignment of the knee (CPAK). Three categories of alignment strategy were defined: true mechanical alignment (tMA), adjusted mechanical alignment (aMA), and no mechanical alignment (noMA). RESULTS: A shift to overall varus component positioning was observed over the years. Joint line obliquity according to CPAK showed a wider spread in later years, and the distribution of tibial and femoral coronal alignment angles expanded over time. CONCLUSION: The study revealed a change in alignment targets and final positioning of components away from neutral biomechanical axes in a large volume of TKAs by a single, classically trained surgeon over five years of using a robotic arm-assisted TKA system with CT-based planning. The most dominant factor for this change was the use of 3D CT planning, allowing the surgeon to assess patient-specific anatomy and plan accordingly. Outcome data is needed to determine if this change in behavior and surgical technique was beneficial. In summary, using a CT scan-based robotically assisted technique led to a gradual and complete shift from tMA to predominantly a non-mechanically aligned philosophy in TKA.

Mako™ Robotic-Arm Assisted Medial Unicompartmental Knee Arthroplasty: Surgical Technique from the Office to the Operating Room.

The utilization of robotic-arm assisted unicompartmental knee arthroplasty (UKA) or partial knee arthroplasty (PKA) for the treatment of medial unicompartmental osteoarthritis has continued to increase. This is in part due to the consistently reproducible accuracy and precision of implant planning, intra-operative ligament balancing software, tracking optimization software, robotic-arm assisted bone preparation, excellent survivorship rates, and improvements in many patient-reported outcomes compared to manual UKA, using the Stryker Mako™ Robotic Partial Knee System (Stryker, Mako Surgical Corp., Mahwah, New Jersey). Training in the utilization of robotic-arm assistance can be time-consuming and comes with an associated learning curve even after the in-person training and coursework is complete, like most procedures. Therefore, our aim was to describe the pre-operative planning and intra-operative surgical technique for using a robotic-arm assisted partial knee system for UKA/PKA in patients who have unicompartmental medial knee osteoarthritis. Specifically, we will discuss: 1) pre-operative planning; 2) operative setup; 3) intra-operative steps; 4) execution of the plan; and 5) trialing, implantation, and final assessments.

Mako® Robotic-Arm Assisted Total Hip Arthroplasty: Avoiding Impingement with Updated THA Software.

The use of robotic-assisted total hip arthroplasty and three-dimensional computed tomography scan-based templating has become increasingly popular over the last 10 years. However, proper planning and execution are vital to producing optimal patient outcomes. In order to achieve these outcomes, the robotic-assisted system requires training, familiarity, and experience. The goal of this article is to provide clear and condensed examples of preoperative planning, as well as adjustments that one can make to avoid impingement. The surgical technique for robotic-assisted total hip arthroplasty is also briefly discussed. Examples will be given using the latest computed tomography (CT) scan-based robotic platform for osteoarthritic hips, with specific examples of various cases of impingement that might be encountered by the surgeon and how to ultimately avoid this problem when performing the arthroplasty. This article, through case histories, will discuss the various principles and adjustments that can be made to place components in the ideal location based on individual anatomy.

Variability of pre-operative functional pelvic tilt in total hip arthroplasty patients.

PURPOSE: Pelvic tilt (PT) is important to consider when planning total hip arthroplasty (THA) due to its dynamic impact on acetabular orientation. The degree of sagittal pelvic rotation varies during functional activities and can be difficult to measure without proper imaging. The purpose of this study was to evaluate PT variation in the supine, standing, and seated positions. METHODS: A multi-centre cross-sectional study was performed that included 358 THA patients who had preo-perative PT measured from supine CT scan and standing and upright seated lateral radiographs. Supine, standing, and seated PT and associated changes between functional positions were evaluated. Anterior PT was assigned a positive value. RESULTS: In the supine position, mean PT was 4° (range, -35° to 20°), where 23% had posterior PT and 69% anterior PT. In the standing position, mean PT was 1° (range, -23° to 29°), where 40% had posterior PT and 54% anterior PT. In the seated position, mean PT was -18° (range, -43° to 47°), where 95% had posterior PT and 4% anterior PT. From standing to seated, the pelvis rotated posteriorly in 97% of cases (maximum 60°) with 16% of cases considered stiff (change ≤ 10°) and 18% of cases considered hypermobile (change ≥ 30°). CONCLUSION: Patients undergoing THA have marked PT variation in the supine, standing, and seated positions. There was wide variability in PT change from standing to seated, with 16% of patients considered stiff and 18% considered hypermobile. Functional imaging should be performed on patients prior to THA to allow for more accurate planning.

Topic selection process in health technology assessment agencies around the world: a systematic review.

OBJECTIVE: The purpose of this study was to systematically review the process for topic selection by health technology assessment (HTA) agencies around the world to provide the knowledge base for the improvement of topic selection frameworks in HTA agencies. METHODS: A systematic search was conducted in PubMed and EMBASE to identify papers up to February 2019. Gray literature was identified by screening the Web sites of HTA agencies on the nonprofit member list of the International Network of Agencies for Health Technology Assessment (INAHTA). Data were extracted for each HTA agency and synthesized, with issues including general contextual information about each agency and the process of topic selection. RESULTS: Out of forty-nine nonprofit members of INAHTA, a total of seventeen HTA agencies with a framework for topic selection were identified from twenty-two included papers/documents. Multiple criteria were used for topic selection in all frameworks and agencies undertook multiple steps, which could include the specification of criteria for topic selection, identification of topics, short listing of potential topics, scoping of potential topics, scoring and ranking of potential topics, and deliberation and decision on final topics for HTA. Shortcomings were found in relation to methods of scoring and ranking as well as lack of monitoring and the evaluation of the process. CONCLUSIONS: Our study provides insights into the current practice of topic selection in HTA agencies. Multiple criteria decision analysis methodology appears highly relevant to these processes. A consensus approach for the development of methods of topic selection would be valuable for the HTA community.

Clinical Outcomes After Computed Tomography-Based Total Knee Arthroplasty: A Surgeon's First 1,000 Cases.

INTRODUCTION: Computed tomography scan (CT)-based three-dimensional (3D) modeling operative technologies have been shown to improve upon many perioperative results of manual total knee arthroplasties (TKAs). Although patient satisfaction has been reported for CT-based TKAs, studies evaluating large cohorts are limited. The purpose of this study was to compare the clinical outcomes of a surgeon's first 1,000 CT-based TKAs with manual TKAs during a minimum follow-up time of approximately six months. Specifically, we analyzed: (1) survivorship; (2) functional outcomes; (3) radiographic outcomes (i.e., alignment, progressive radiolucencies); and (4) complications. MATERIALS AND METHODS: A total of 1,000 consecutive primary CT-based total knee arthroplasty cases (988 patients) performed by a single surgeon at a single center between July 1, 2016 and July 1, 2021 were compared to a total of 1,000 consecutive manual TKAs (996 patients) completed by the same surgeon between May 18, 2013 and July 1, 2016. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) surveys were collected at approximately six months postoperatively. Subgroup analyses were performed on the physical function and pain scores. Follow-up radiographs were also examined for alignment, progressive radiolucencies, and/or loosenings. RESULTS: There was 100% survivorship at approximately six months follow up. The mean physical function score for the manual cohort and CT-based cohort were 10 ± 4 (range, 0 to 32) and 5 ± 4 (range, 0 to 22), respectively (p<0.05). The mean pain score for the manual cohort and CT-based cohort were 4 ± 4 (range, 0 to 20) and 3 ± 2 (range, 0 to 15), respectively (p<0.05). The mean total WOMAC score for the manual cohort and CT-based cohort were 13 ± 9 (range, 0 to 44) and 8 ± 7 (range, 0 to 33), respectively (p<0.05). None of the manual or CT-based cases exhibited progressive radiolucencies by final follow up. There were no postoperative medical and/or surgical complications at final follow up in the two cohorts. DISCUSSION/CONCLUSIONS: The 1,000 CT-based TKA clinical outcomes from this study continue to support great survivorship and radiographic outcomes, minimal complications, as well as improved physical function, pain, and total WOMAC scores. Therefore, those who undergo CT-based 3D modeling total knee arthroplasties should have the advantage of superior patient satisfaction.

Total Knee Arthroplasty in the Valgus Knee: Can New Operative Technologies Affect Surgical Technique and Outcomes?

INTRODUCTION: Valgus knee deformities can sometimes be challenging to address during total knee arthroplasties (TKAs). While appropriate surgical technique is often debated, the role of new operative technologies in addressing these complex cases has not been clearly established. The purpose of this study was to analyze the usefulness of computed tomography scan (CT)-based three-dimensional (3D) modeling operative technology in assisting with TKA planning, execution of bone cuts, and alignment. Specifically, we evaluated valgus TKAs performed using this CT-based technology for: (1) intraoperative implant plan, number of releases, and surgeon prediction of component size; (2) survivorship and clinical outcomes at a minimum follow up of one year; and (3) radiographic outcomes. MATERIALS AND METHODS: A total of 152 patients who had valgus deformities receiving a CT-based TKA performed by a single surgeon were analyzed. Cases were performed using an enhanced preoperative planning and real-time intraoperative feedback and cutting tool. The surgeon predicted and recorded implant sizes preoperatively and all patients received implants with initial and final implant alignment, flexion/extension gaps, and full or partial soft tissue releases recorded. A modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR.) scores were collected preoperatively and at approximately six months and one year postoperatively. Preoperative coronal alignment ranged from 1 to 13° valgus. Follow-up radiographs were also evaluated for alignments, loosenings, and/or progressive radiolucencies. RESULTS: A total of 96% of cases were corrected to within 3° of mechanical neutral. For outlier cases, initial deformities ranged from valgus 5 to 13°, with final alignment ranging from 4 to 8° valgus (mean 4° correction). Patients had mean femoral internal rotation of 2° and mean femoral flexion of 4°. The surgeon was within one size on the femur and tibia 94 and 100% of the time, respectively. Only one patient required a lateral soft tissue release and one patient had osteophytes removed, which required a medial soft tissue release. Five patients required manipulations under anesthesia. Aside from these, there were no postoperative medical and/or surgical complications and there was 100% survivorship at final follow up. WOMAC and KOOS, JR. scores improved significantly from a mean of 21 ± 9 and 48 ± 10 points preoperatively to 4 ± 6 (p<0.05) and 82 ± 15 (p<0.05) at final follow up, respectively. None of the cases exhibited progressive radiolucencies by final follow up. DISCUSSION: A limitation of this study was not evaluating dynamic kinematics in these patients to determine if rotation had any effects on kinematics. Future studies will evaluate this concern. Nevertheless, the technology successfully assisted with planning, executing bone cuts, and achieving alignment in TKAs complicated by the deformity. This may allow surgeons to predictably avoid soft tissue releases and accurately know component sizes preoperatively, while consistently achieving desired postoperative alignment. CONCLUSIONS: This study demonstrated the utility of CT-based 3D modeling techniques for challenging valgus deformity cases. Use of 3D modeling allowed the TKA components to be positioned according to the patient's anatomy in the coronal, transverse, and sagittal planes. When making these intraoperative implant adjustments, the surgeon may choose to place components outside the preoperative planning guidelines based on the clinical needs of the patient.

Estimation of Femoral Version During Total Hip Arthroplasty: Surgeon Visual Assessment versus Robotic-Arm Assisted Technology.

INTRODUCTION: Malposition of THA implants can lead to many complications, some of which may necessitate reoperation. Thus, proper implant placement is critical for optimizing patient outcomes. In addition, intraoperative visual estimation of stem position has been shown to be unreliable. Therefore, the purpose of this study was to compare a surgeon's visual estimation of femoral version to the actual version captured using a three-dimensional robotic-arm assisted platform. MATERIALS AND METHODS: A prospective study of 25 THAs performed by a single surgeon was performed. The mean version, as estimated by intraoperative visual assessment, was compared to that measured by the robotic-arm assisted technology software using a two-sided t-test. Outliers were evaluated for the following intervals: 1 to 5°, 6 to 10°, and greater than 10°. A separate analysis was performed for anteverted versus retroverted stems. RESULTS: The mean version, as estimated by intraoperative visual assessment, was 9.16 ± 4.02° (range, 3 to 18°) compared to 3.52 ± 8.66° (range, -12 to 19) as measured by the robotic-arm assisted software (P=0.005). The surgeon's estimates of broach version and those measured by the robotic-arm assisted software were identical in three cases (12%). The evaluation methods differed by 1 to 5° in six cases (24%), 6 to 10° in 10 cases (40%), and greater than 10° in six cases (24%). Larger differences between methods were noted for cases in which the stem was found to be in anteversion by the robotic-arm assisted software. CONCLUSIONS: Visual estimation of femoral implant version differed significantly from measurements captured by three-dimensional robotic-arm assisted imaging. This suggests that estimating stem position intraoperatively by eye is not reliable, even when done by an experienced surgeon. The use of robotic-arm assisted technology may be recommended for determining femoral stem version intraoperatively.

Surgical Tray Optimization and Efficiency: The Impact of a Novel Sealed Sterile Container and Instrument Tray Technology.

INTRODUCTION: As bundle payments have begun focusing on orthopaedic procedures, particularly total knee arthroplasties (TKAs), surgeons and hospitals have evaluated methods for improving efficiency. Few studies have investigated the impact of novel, sealed-container and instrument-tray technology on turnover and costs. Therefore, the purpose of this study was to compare traditional and sealed container-sterilized TKA surgical trays by: 1) investigating the setup and clean-down time in the operating room (OR); 2) examining trays processing time in central sterile supply (CS); and 3) estimating OR and CS costs and waste produced. MATERIALS AND METHODS: An interdisciplinary team determined points throughout a TKA tray single-case life cycle that could cause variations in turnover time. The times were recorded for two different TKA tray configurations. Process A utilized instruments housed in vendor trays that were "blue" wrap sterilized, while Process B employed optimized trays that were sealed container-sterilized. Times were recorded during preoperative setup and postoperative clean down in the OR and CS. Reductions in mean OR or CS times were used to estimate cost savings. Wastes were analyzed for each method. Statistical analyses using Student t-tests were used to determine statistical differences and a p-value of less than 0.05 was considered significant. RESULTS: Overall, the use of optimized trays and sealed sterilization containers reduced the turnover time by 57 minutes and the number of trays by a mean of three. OR and CS processing yearly savings were estimated to be $249,245. Waste disposal was an estimated 10,590 ounces and 450 ounces for traditional and sealed containers, respectively. CONCLUSION: Novel sealed sterilization containers demonstrated increased efficiency in the total turnover time of TKA trays. This is important for surgeons participating in bundle payments who perform surgery in a hospital and ambulatory surgery center. Reduced turnover time could potentially increase case load and decrease the need for extra instrumentation or loaner trays. This simple means of increasing efficiency could be used as a model for surgeons wishing to streamline surgical trays and reduce costs.

Robotic-Assisted Total Knee Arthroplasty in the Presence of Extra-Articular Deformity.

INTRODUCTION: Tibial or femoral extra-articular deformities complicate the goal achieving optimal mechanical axis alignment for successful total knee arthroplasty (TKA) outcomes. In the presence of these extra-articular deformities, standard operative techniques and instruments may not be reliable. Robotic-arm assisted technology was developed to help achieve a well-aligned and balanced knee in a variety of clinical scenarios. Although prior case series have reported on the use of robotic-arm assisted devices for cases with severe angular deformity, there is a lack of data concerning the use of the robotic device for patients with other potentially complex surgical factors. Therefore, the purpose of this series was to present cases in which the robotic-arm assisted TKA application was used in the setting of extra-articular deformities to educate the surgeon community on this potentially useful method to address these complex cases. MATERIALS AND METHODS: Three cases of patients who underwent robotic-arm assisted TKA in the setting of preoperative extra-articular deformities were identified. These included one with femoral and tibial fracture malunion, another with a proximal tibial fracture nonunion, and another with a healed tibial plateau fracture. Patient clinical histories, intraoperative surgical techniques, and postoperative outcomes were obtained. Specific focus was placed on the surgical management of the patient's pre-existing deformity. RESULTS: These three case reports are discussed in detail, with emphasis on preoperative planning and intraoperative techniques. The robotic software was able to appropriately consider the extra-articular deformity in the preoperative and real-time updated intraoperative plans. Doing so, the surgeon was able to achieve balanced and aligned TKA in each case. All three patients underwent robotic-assisted total knee arthroplasty with no intraoperative or postoperative complications. For all patients, their anteroposterior and lateral radiographs demonstrated well fixed and aligned femoral and tibial components with no signs of loosening or osteolysis. On physical exam, all patients had excellent range-of-motion with mean flexion of 122° (range: 120 to 125° of flexion) at final follow up. DISCUSSION: The decision on how to best approach TKA in patients with extra-articular deformity should be based on an extensive patient history, physical examination, and thorough evaluation of the magnitude and proximity of the deformity to the knee joint. Utilizing preoperative CT-scans with a 3D plan for robotic-arm assisted surgery allowed for appropriate assessment of the deformity preoperatively and execution of a plan for a balanced and aligned total knee arthroplasty. We have demonstrated excellent results utilizing robotic-arm assisted TKA in these complex cases.

Survivorship and Radiographic Analysis of Highly Porous Acetabular Cups Designed for Improved Osseointegration Potential.

INTRODUCTION: A variety of highly porous materials have been used to obtain biological acetabular fixation after total hip arthroplasty (THA). Due to their improved surface-coated properties, new highly porous titanium metal implants have shown potential to promote prosthesis osseointegration. Therefore, the purpose of this multicenter study was to evaluate: 1) overall acetabular cup survivorship; 2) postoperative complications; and 3) radiographic signs of loosening and radiolucencies in patients who received a new highly porous titanium metal cup. MATERIALS AND METHODS: A total of 81 patients who underwent primary THA and received a new porous acetabular cup between May 16, 2013 and January 27, 2016 at three academic centers were included for analysis. There were 40 women (49%) and 41 men (51%) who had a mean age of 65 years (range, 38 to 95 years) and a mean body mass index (BMI) of 28 kg/m2 (range, 16 to 43 kg/m2). The minimum follow up time was two years and seven months (range, 2 to 4 years). The cup was engineered with fully interconnected porosity designed for potential long-term biologic fixation. Medical records were reviewed to assess for any revision surgeries and postoperative complications, and the most recent radiographs were reviewed for signs of loosening or radiolucencies. RESULTS: Overall, acetabular component survivorship, free of fixation failure or aseptic loosening, was 100%. Two patients underwent revision due to dislocations; however, revisions were performed because no constrained or dual mobility liners were available for the shell at the time. Both patients had successful outcomes and were doing well at final follow up with no further episodes of dislocation. There was one open reduction internal fixation for a periprosthetic femoral fracture, and three polyethylene revisions were performed for instability. In all of these cases, the acetabular cup was retained. On radiographic evaluation of antero-posterior pelvis radiographs, there was one patient who had radiolucencies of <1mm in Zone 1 and Zone 2 at 15 months after surgery, and another patient demonstrated radiolucencies of <1mm in Zone 2 and 3 at one-year follow up. At a minimum of two-year follow up, both patients had non-progressive and stable findings. CONCLUSION: The results of this study demonstrated excellent survivorship, and there were no radiographic failures of this acetabular cup in primary total hip arthroplasty patients. Although two patients were found to have minimal (<1mm) radiolucencies, these were not progressive. Longer follow-up studies are needed to further assess the survivorship and outcomes of this new acetabular cup; however, based on the results of this study, these are expected to be favorable.

Dying at home: experience of the Verdun local community service centre.

OBJECTIVE: To demonstrate that it is possible for a team of palliative care nurses in an urban centre to care for more than 50% of their terminally ill patients at home until they die, and that medical care delivered in the home is a determining factor in death at home versus death in a hospital. DESIGN: Analysis of place of death of terminally ill patients who died in 2012 and 2013 (N = 212) and who had been cared for by palliative care nurses, by type of medical care. SETTING: The centre local de services communautaires (CLSC) in Verdun, Que, an urban neighbourhood in southwest Montreal. PARTICIPANTS: A total of 212 terminally ill patients. MAIN OUTCOME MEASURES: Rate of deaths at home. RESULTS: Of the 212 patients cared for at home by palliative care nurses, 56.6% died at home; 62.6% received medical home care from CLSC physicians, compared with 5.0% who did not receive medical home care from any physician. CONCLUSION: Combined with a straightforward restructuring of the nursing care delivered by CLSCs, development of medical services delivered in the home would enable the more than 50% of terminally ill patients in Quebec who are cared for by CLSCs to die at home--something that most of them wish for.

Initiating decision-making conversations in palliative care: an ethnographic discourse analysis.

BACKGROUND: Conversations about end-of-life care remain challenging for health care providers. The tendency to delay conversations about care options represents a barrier that impedes the ability of terminally-ill patients to participate in decision-making. Family physicians with a palliative care practice are often responsible for discussing end-of-life care preferences with patients, yet there is a paucity of research directly observing these interactions. In this study, we sought to explore how patients and family physicians initiated decision-making conversations in the context of a community hospital-based palliative care service. METHODS: This qualitative study combined discourse analysis with ethnographic methods. The field research lasted one year, and data were generated through participant observation and audio-recordings of consultations. A total of 101 consultations were observed longitudinally between 18 patients, 6 family physicians and 2 pivot nurses. Data analysis consisted in exploring the different types of discourses initiating decision-making conversations and how these discourses were affected by the organizational context in which they took place. RESULTS: The organization of care had an impact on decision-making conversations. The timing and origin of referrals to palliative care shaped whether patients were still able to participate in decision-making, and the decisions that remained to be made. The type of decisions to be made also shaped how conversations were initiated. Family physicians introduced decision-making conversations about issues needing immediate attention, such as symptom management, by directly addressing or eliciting patients' complaints. When decisions involved discussing impending death, decision-making conversations were initiated either indirectly, by prompting the patients to express their understanding of the disease and its progression, or directly, by providing a justification for broaching a difficult topic. CONCLUSIONS: Decision-making conversations and the initiation thereof were framed by the organization of care and the referral process prior to initial encounters. While symptom management was taken for granted as part of health care professionals' expected role, engaging in decisions regarding preparation for death implicitly remained under patients' control. This work makes important clinical contributions by exposing the rhetorical function of family physicians' discourse when introducing palliative care decisions.

Robotic-arm-assisted conversion of unicompartmental knee arthroplasty to total knee arthroplasty.

Introduction: The purpose of this study was to describe a novel robotic-arm-assisted UKA to TKA conversion technique and evaluate the patient reported and clinical outcomes in these patients. Methods: A retrospective review between 2017 and 2022 was conducted of patients that underwent robotic-arm-assisted UKA to TKA conversion. Charts were reviewed for patient demographics, indications for conversion from UKA to TKA, operative technique, implants used, postoperative complications, and patient-reported outcome measures (PROMs). The surgical technique resembles that of primary TKA, with the major exception of registering the robotic arm with retained UKA implants and removing the implants only when verification is complete. There were 44 robotic-arm-assisted UKAs in 41 patients were included in the study. Indications for UKA conversion to TKA included: 33 patients who had osteoarthritis progression (75%), 7 aseptic loosening (16%), 2 unspecified pain (4.5%), 1 polyethylene wear (2.3%), and 1 prosthetic joint infection (2.3%). Uncemented cruciate-retaining (CR) implants were used in 38 of the 44 robotic-arm-assisted TKAs (86.5%). The other six utilized cemented implants: four CR femurs (9.1%), six tibial baseplates (13.6%), four tibial stems (9.1%), and four medial tibial augments (9.1%). Results: The PROMs significantly improved at 1-year follow-up, with the average KOOS JR score increasing from 48.1 to 68.7 (P < 0.001), and the r-WOMAC score decreasing from 25.7 to 10.6 (P = 0.003). Two patients developed prosthetic joint infections (4.5%), one developed aseptic loosening of the femoral component (2.3%), and one developed a superficial surgical site infection requiring superficial irrigation and debridement (2.3%). Overall survivorship was 93.18% at 1.8 years, and aseptic survivorship was 97.73%. Conclusion: Robotic-arm-assisted UKA to TKA conversion exhibited improved patient-reported outcomes and low revision and complication rates. Improved implant placement achieved with robotic-arm-assistance may improve the functional and clinical outcomes following these surgeries.

Three-dimensional-based native alignment phenotype classification system: Description for use in planning for deformities during total knee arthroplasty.

Introduction: Total knee arthroplasty (TKA) is a complex surgical procedure that traditionally relies on two-dimensional radiographs for pre-operative planning. These radiographs may not capture the intricate details of individual knee anatomy, potentially limiting the precision of surgical interventions. With advancements in imaging technology, there is an opportunity to refine TKA outcomes. This study introduces the Native Alignment Phenotype classification system that is based on pre-operative 3-dimensional computed tomography (CT) scans, aiming to provide a more detailed understanding of knee deformities and their influence on characterizing knee osteoarthritis and planning for TKA procedures. Methods: There were 1406 pre-operative non-weight-bearing CT scans analyzed by a single surgeon experienced with robotically-assisted total knee arthroplasties. These scans were converted into three-dimensional models, focusing on the coronal and sagittal planes. Intraoperatively, the robotic system was used to capture native coronal and sagittal deformities for each patient. These values were captured with the patient's leg held in a non-stress, extension pose. A new classification system, 'The Native Alignment Phenotype', was developed to categorize the specific differences between individual knees. Results: There were four primary knee malalignments identified: varus deformity; valgus deformity; and two deformities in the sagittal plane. These malalignments were further categorized based on the degrees of deviation, creating groups with 5° coronal and sagittal ranges. A total of 77 phenotypic alignment patterns were found based on the analyzed cohort. In the coronal plane, varus HKA deformity between 6 and 10° was the most common, with 36.9% of the cases, followed by varus HKA alignment, which was between 0 and 5°, representing 34.3% of the cases. In the sagittal plane, neutral and flexion contracture deformities between 0 and 5° were the most common, with 32.6% of the cases, followed by a fixed flexion contracture alignment, which was between 6 and 10°, representing 28.7% of the cases. When combining coronal and sagittal planes, the most common alignment was the varus between 0 and 5° with a flexion contracture between 0 and 5° (12.5% of cases), closely followed by the varus between 6 and 10° with a flexion contracture between 6 and 10° (12.4% of cases). Conclusion: The Native Alignment Phenotype classification system offers a nuanced understanding of knee deformities based on three-dimensional (CT scan) assessments, potentially leading to improved surgical outcomes in TKA. By leveraging the detailed data from the CT scans, this system provides a more comprehensive view of the knee's anatomy, emphasizing the importance of individualized, data-driven approaches in knee surgery.

A multicentre prospective assessment of the utility of robotic assisted total hip arthroplasty with virtual range of motion on intraoperative implant positioning.

BACKGROUND: The growing adoption of robotic-assistance during total hip arthroplasty (THA) has provided novel means through which a patient's anatomy and dynamic spinopelvic relationship can be incorporated into surgical planning. However, the impact of enhanced technologies on intraoperative decision-making and changes to component positioning has not yet been described. METHODS: A multicentre, prospective study included 105 patients (52% women) patients who underwent robotic-assisted THA with the integration of software that incorporates a patient's pelvic tilt (PT) and virtual range-of-motion (VROM) for impingement modeling. The primary outcome of the study was the percentage of patients who underwent changes to the preoperative plan for cup position after incorporating the data from the software. RESULTS: Utilising the intraoperative VROM information, the preoperative plan for cup position was changed from the default (40° inclination and 20° anteversion) in 82/105 (78%) cases. When stratifying by spinopelvic mobility, 64% were considered normal (change ⩾ 10° and ⩽30°), 27% were stiff (change < 10°), and 9% were hypermobile (change > 30°). For all cohorts, the majority of cases (78%) deviated from the 40° inclination and 20° version target. When evaluating the proportion of cases within the Lewinnek and Callanan safe zones based on spinopelvic mobility, 19% of cases within the normal group were planned outside of both zones compared to 39% of stiff cases and 10% of hypermobile cases. CONCLUSIONS: Utilising the latest version of robotic-assisted THA software, the preoperative plan for cup position was changed in the vast majority (78%) of patients, causing substantial deviations from traditional, generic cup targets.

Patient-reported and radiographic outcomes of a porous-coated acetabular cup in robotic assisted total hip arthroplasty at 2-year follow up.

Introduction: Several implant manufacturers have developed ultra-porous metal substrate acetabular components recently. Despite this, data on clinical and radiographic outcomes remain limited. Our study evaluated postoperative patient-reported outcome measures (PROMs) and radiographic analyses in patients fitted with a novel acetabular porous-coated component. Methods: A total of 152 consecutive patients underwent a total hip arthroplasty by a single orthopaedic surgeon. All patients underwent surgery utilizing the same CT-scan based robotic-assisted device with the same porous cementless acetabular shell. They received standardized postoperative physical therapy, rehabilitation, and pain protocols. Preoperatively, first postoperative visit, 6-months, 1-year, and 2-years, patients were evaluated based on Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, physical function, and total scores; 2) Patient-Reported Outcomes Measurement Information System (PROMIS)-10 physical and mental scores; 3) Hip Disability and Osteoarthritis Outcome Score (HOOS)-Jr scores; as well as 4) acetabular component positions and 5) evidence of acetabular component loosening. Results: Significant improvements were observed by 6 months in WOMAC pain, physical function, and total scores (p < 0.05), maintained at 1 and 2 years. PROMIS-10 physical scores also improved significantly from preoperative to 6 months postoperative and remained so at 1 and 2 years postoperative (p < 0.05). No significant changes were found in PROMIS-10 mental scores. HOOS-Jr scores significantly improved from preoperative to 6 months postoperative and remained so through 2 years (p < 0.05). At 6 months, slight changes were noted in abduction angle and horizontal and vertical offset. Radiolucencies, initially found in 3 shells, reduced to 1 shell with 2 new radiolucencies by 6 months, and remained stable with no subsequent operative interventions. At 1 year and 2 years, no radiographic abnormalities were noted, including complete resolution of prior radiolucencies as well as stable components. Conclusion: This porous cementless acetabular shell, implanted with CT-scan-based robotic-assisted techniques, demonstrated excellent postoperative PROMs at 2 years. Stable radiolucencies suggest good component stability. The early stable clinical and radiographic results suggest promising long-term outcomes with this device. Level of evidence: III (retrospective cohort study).