bluuebunny/crossref_metadata_2025 huggingface dataset:
No changes in bone mineral density following total knee arthroplasty using an all polyethylene tibial component
Authors: Ewen Alistair , Rae Jill , Jeldi Artaban , Picard Frederic
Published: October 2019

Polyethylene particles produced in metal backed tibias (MBT) are understood to contribute to bone loss and component loosening. This, and better surgical techniques (including computer navigation) and increasing costs have renewed interest in all poly tibias (APT). We investigated peri-APT bone mineral density (BMD) in patients; expecting to find no differences between two post-operative values.

Patients over 65 years, with BMI ≤ 37.5 and no previous joint replacements were recruited to have TKA using the Columbus APT with computer navigation (OrthoPilot). The study cohort (n=26) had a mean age of 71.9 (sd 4.35), a BMI of 31.2 (sd 3.8). The BMD examinations were performed six weeks and 18 months post-operatively. Six regions-of-interest (ROI) were identified on anterior/posterior and lateral scans. For each ROI at each time point, relative BMD differences (RDs) were determined between limbs and RDs at the two time points were compared.

No differences were found between the two RDs for any ROI. No revisions or complications were reported. At 18 months post-operatively, 78.3% of the cohort were “very satisfied” with the outcome of their surgery and Oxford Knee Scores improved significantly compared to pre-operatively (p<0.005). Mean knee range of motion was 102° (sd 10.7◦) and mean leg alignment was 2.0° valgus (1°varus-6°valgus).

Results from BMD suggest that implants were well fixated. Patients reported excellent satisfaction and function. We believe that using APTs and computer navigation is a viable and cheaper option to MBT for patients who are less active, have lower BMI and good bone quality.
Preliminary Planning for a Multi-institutional Database for Ultrasound Bone Segmentation
Authors: Pandey Prashant , Patel Hridayi , Guy Pierre , Hacihalilogu Ilker , Hodgson Antony J.
Published: October 2019

Ultrasound (US) bone segmentation is a key component in many US-based computer assisted orthopaedic systems. Although numerous US bone segmentations techniques exist, there remains no direct way of comparing their performances. This is primarily due to the lack of an accessible US bone image database, and secondly due to a lack of standard vali- dation practices. To address this issue, we are beginning a multi-institutional international collaboration across multiple research centres with the aim of creating an open database for US bone segmentation consisting of several thousand US images and corresponding bone surface segmentations. Our collaboration also aims to address outstanding issues in US bone segmentation, such as determining the reliability of manual segmentations and establishing a set of evaluation metrics which should be reported in future segmentation studies. Finally, we strongly encourage interested researchers to join and contribute to this project as this will help to create a more diverse database and knowledgeable collaboration.
Pelvic Tilt Cannot Be Accurately Predicted Using Anteroposterior Radiographs
Authors: Cizmic Zlatan , Gabor Jonathan , Eftekhary Nima , Rudy Hayeem , O'Sullivan Michael , Schwarzkopf Ran , Buckland Aaron , Vigdorchik Jonathan
Published: October 2019

INTRODUCTION: Pelvic positioning during total hip arthroplasty (THA) can affect the functional position of the acetabular component. A comprehensive understanding of pelvic orientation prior to THA is necessary to allow for proper cup positioning and mitigate the risks of complications associated with component malpositioning. Measurements using anteroposterior (AP) radiographs have been described as an effective means of accurately predicting pelvic functional orientation. The purpose of our study was to describe the accuracy of assessing pelvic tilt using AP radiographs alone.

METHODS: An online survey was created and sent to a cohort of fellowship-trained adult reconstruction surgeons. The survey consisted of 65 standing AP pelvis radiographs. Participants were asked to score each radiograph as 1) anterior pelvic tilt > 10 degrees, 2) posterior pelvic tilt > 10 degrees, or 3) neutral. Responses were then compared to measurements of pelvic tilt made on lateral standing pelvic radiographs. Categorical and continuous variables were compared using chi-squared, unpaired, two-tailed student’s T tests, and ANOVA.

RESULTS: 135 surgeons completed the survey. The average correct predictive value of pelvic tilt between all surgeons was 53.2%. 51.2% of responding surgeons performed greater than 100 cases per year. 50% of surgeons reported that they were “not so familiar” or “somewhat familiar” with the principles of spinopelvic mobility. 43.5% of surgeons reported that they did not routinely use spinopelvic mobility principles in THA planning.

DISCUSSION: The standing AP pelvis radiograph is poorly predictive of pelvic tilt. Pre-operative evaluation of spinopelvic parameters requires AP and lateral pelvic views for detailed assessment and accurate pre-operative planning.
One and Two Year Postoperative Patient Reported Outcomes of Robotic-Assisted Total Knee Arthroplasty
Authors: Blum Christopher , Plaskos Christopher , Hussein Adil , Koenig Jan A
Published: October 2019

Total knee arthroplasty is a successful procedure. However, there is still area for improvement as up to 15-20% of patients remain unsatisfied. Robotic-assisted surgery (RAS) may improve patient outcomes by providing a reproducible way of obtaining neutral mechanical alignment of the limb, which has been shown to reduce early revisions and correlate with patient reported outcomes after surgery.

We prospectively enrolled 106 patients undergoing robotic-assisted TKA by a single surgeon performing a measured-resection femur-first technique using the OMNIBotic system. Patients completed a KOOS and New Knee Society Score (KSS) pre-operatively and at 3, 6, 12, and 24 months (M) postoperatively. Changes in the five KOOS sub-scales were compared to available literature data from the FORCE – TJR cohort, as well as to individual studies reporting on conventional and computer-assisted TKA.

When compared to FORCE-TJR 6-month (M) and 2-year (Y) data, the RAS cohort had significantly higher improvements at 6M for pain (40.5 vs. 31.1, p<.001) and at 2Y for all five KOOS sub-scores. The larger improvement was due to the RAS cohort having lower baseline KOOS scores than the FORCE-TJR cohort, except for the Sports-Recreation sub-score, which was similar pre- operatively but significantly higher post-operatively for the robotic cohort. Rates of dissatisfaction with knee pain level and function using the KSS after RAS were 3.0%, 1.0%, and 2.7% at 6, 12, and 24M postoperatively, respectively.

Despite having poorer joint function and higher pain pre-operatively, robotic-assisted TKA patients achieved excellent self-reported outcomes, with significantly higher levels of improvement through two years post-surgery when compared with large national cohort studies. Further controlled clinical studies are warranted to determine if these results translate to other groups of surgeons, centers and patients.
Anterior Mechanical Navigation Device is as Accurate as Lateral Device for Hip Socket Position
Authors: Freccero David , Koh Justin , Kang Jeansol , Fang Chris , Smith Eric
Published: October 2019

Objectives: In total hip arthroplasty (THA), accurate acetabular component position promotes prosthetic hip joint stability and longevity, and minimizes polyethylene wear. Image-based mechanical navigation is known to improve accuracy and reproducibility of accurate cup position intraoperatively via the posterior approach and the superior capsular approach. The purpose of this study was to assess the accuracy of acetabular component position using image-based mechanical navigation via the direct anterior approach (DAA). Methods: We prospectively followed 96 patients who underwent THA with one fellowship-trained arthroplasty surgeon over a nine-month period. Thirty-three patients underwent DAA THA with the anterior HipXpert device (Group 1), and 63 patients underwent posterior approach THA with the lateral HipXpert mechanical navigation device, serving as an operative control group (Group 2). Standard postoperative plain film radiographic measurements of acetabular component inclination and anteversion were assessed. Results: The average inclination angle was 38.6 degrees and 40.6 degrees in Groups 1 and 2, respectively. The average anteversion angle was 27.6 degrees and 30.1 degrees in Groups 1 and 2, respectively. There were no postoperative hip dislocations and no study patients underwent revision THA at an average follow-up of 12 months. There were no patient outliers in Groups I or II with inclination angles or anteversion angles outside 10 degrees of the preoperatively planned values. Conclusion: The anterior HipXpert mechanical navigation device enhances accurate acetabular component position and may reduce outlier component placement. Acetabular socket position is as accurate using the anterior device as it is using the lateral device.
Long term Patient Outcomes following Navigated Knee Replacement:A Retrospective analysis
Authors: Jeldi Artaban , Holloway Nicholas , Ewen Alistair , Picard Frederic
Published: October 2019

Total knee replacements (TKR) are often deemed successful when patients recover and maintain their functionality both in the short and long term. The other main indicator for success is the revision rate following TKR. This study analyses the long term results of navigated TKR based on patient related outcomes in terms of patient satisfaction, Oxford Knee Score (OKS) and also knee revision rates.

The retrospective data of all patients who underwent navigated Columbus TKR from the author’s institution from 2005 to 2011 was analysed and compared to the national database. The overall cohort size was 1679 with a mean age of 68.81yrs (sd 8.46). The OKS, satisfaction scores, complication and revision rates were compiled and evaluated up to ten years post-operatively. Patient reported outcomes were recorded six weeks, one, two, five and ten years post-operatively.

The results from the OKS and satisfaction scores demonstrated marked improvement throughout recovery to the ten year time point. The OKS had a mean improvement of 16.6 from the pre-operative score at the 10 year time point and the satisfaction scores improved at each follow-up and remained high at the 10 year time point. A total of 61 complications and 36 revisions recorded, with infection being the major cause for revisions.

This survey has identified and established that the majority of patients undergoing knee arthoplasty using the Columbus total knee system and computer navigation function reasonably well in the long term and the revision and complication rates in this hospital are compare well with national levels..
Relationship of the tibial tuberosity (TT) position, tibial tuberositytrochlear groove (TT-TG) distance, and internal and external rotation of the knee under weight-bearing conditions
Authors: Asseln Malte , Meere Patrick , Walker Peter , Radermacher Klaus
Published: October 2019

An important factor which influences the clinical outcome of total knee arthroplasty (TKA) is the internal/external rotational alignment of the femoral and tibial components. A rotational error of few degrees has been found to be clinically important and linked to anterior knee pain [1] and patellofemoral problems [2]. A commonly used reference to align the tibial component rotationally is the tibial tuberosity (TT). However, Howell et al. [3] showed that the medial/lateral TT position varies strongly between patients and represents an unreliable landmark during (passive) kinematic component alignment. Thereby, passive kinematics differs from active kinematics [4,5]. For example, under weight-bearing conditions the magnitude of internal/external rotation is greater and occurs earlier [6]. In the active situation, a relative internal rotation of the tibial component increases the Q-angle with a change in the force vector of the extensor mechanism.

An established radiographic measure to quantify the relative rotational alignment of the femur and tibia in extension is the tibial tuberosity-trochlear groove (TT-TG) distance. It has been measured recently at different flexion angles under non-weight-bearing conditions [7]. However, Izadpanah et al. [8] reported that it also depends on weight-bearing. Hence, the complex function of the extensor mechanism in terms of the relationship between TT position, TT-TG distance, and internal/external rotation under weight-bearing conditions is still unknown and accordingly component rotational alignment targets.

The aim of the study was to investigate the relationship between TT position, TT-TG distance, and internal/external rotation of the knee in the active (weight-bearing) situation.
In-vivo precision of a non-invasive ultrasound-based device to measure pelvic tilt for THA
Authors: Dardenne Guillaume , Pluchon Jean-Philippe , Letissier Hoel , Guezou-Philippe Aziliz , Gérard Romain , Lefèvre Christian , Stindel Eric
Published: October 2019

The cup orientation plays a major role in the long-term implant stability following Total Hip Arthroplasty (THA). Because of the patient specific spine-hip kinematics, the safe zone introduced by Lewinnek is more and more controversial. Several solutions have been recently developed to take into account such parameter for THA but are all either invasive, difficult to use or expensive. A non-invasive ultrasound (US) based device has been recently proposed which allows the acquisition of the pelvic tilt in different daily positions. The goal of this study is to analyze the in-vivo intra and inter-observer precision of this device. Measurements were realized by three physicians on three healthy subjects having a low, medium and high Body Mass Index (BMI). Among the three physicians, there were an expert, an intermediate, and a novice user. For each subject, the pelvic tilt was measured ten times by the three physicians in the supine, standing and sitting positions. The inter and intra-observer precisions have been analyzed using the intraclass correlation coefficient (ICC) and according to the BMI, the positions and the user expertise level. The inter-observer precision was therefore excellent whatever the BMI. It was also excellent regarding the supine and the sitting positions and good concerning the standing position. The in-vivo intra-observer precision was excellent for all measurements and whatever the user’s expertise, the BMI and the positions. This study shows therefore that the precision of our system meets the clinical requirement. Introduction
The interleaved partial active shape model (IPASM) search algorithm – towards 3D ultrasound-based bone surface reconstruction
Authors: Hohlmann Benjamin , Radermacher Klaus
Published: October 2019

Several orthopedic applications require a three-dimensional model of the bone. Ultrasound is a radiation-free and cheap alternative to the state-of-the-art imaging modalities if its limitations in terms of image quality and viewing range can be overcome. This work presents in-vitro as well as in-vivo experiments evaluating the IPASM search, a method for combined segmentation, registration as well as extrapolation. The algorithm is capable to reconstruct the distal surface of a phantom femur with an average surface distance error of roughly 1mm in case of in-vitro as well as below 2mm for in-vivo records, even if the shape varies strongly from the initial model.
Robotic-arm assisted total knee arthroplasty improves precision and delivers early outcomes superior to manual approach
Authors: Zhang Jenny , Sodhi Nipun , Dushaj Kristina , Mont Michael , Hepinstall Matthew
Published: October 2019

Haptic robotic-arm assisted technology improves accuracy in unicompartmental knee replacement through utilizing a preoperative 3-D plan, optical navigation for real-time intraoperative feedback on soft tissue laxity, and robotic arm for precise bone preparation. This technology became clinically available for total knee arthroplasty (TKA) in 2016. We present outcomes from the early adoption of this technique.

A retrospective chart review compared data from the first 120 robotic-arm assisted TKAs performed December 2016 through July 2018 to the last 120 manually instrumented TKAs performed May 2015 to December 2016, prior to robotic technology adoption.

Robotic surgery was associated with significantly increased anesthesia (212 vs 187 mins, p < 0.01) and operative (135 vs 112 minutes, p < 0.01) time. The robotic group had a lower hospital length-of-stay (2.7 vs. 3.4 days, p < 0.001). Discharge to home was not statistically different between robotic and manual groups (89% vs. 83%, p = 0.2). Robotic technology was associated with decreased variability in implant positioning, with smaller variances in the lateral distal femoral angle (LDFA; 3.5 vs 6.6 degrees, p < 0.01) and posterior tibial slope (1.8 vs. 5.3 degrees, p < 0.01). Mean limb alignment, as measured by tibiofemoral angle, was slightly less valgus in the robotic group (3.9 vs 4.4 degrees, p = 0.09). Postoperative range of motion was significantly increased for robotic-arm assisted TKA patients, with less flexion contracture at 2-weeks (1.8 vs. 3.3 degrees, p < 0.01), 7-weeks (1.0 vs. 1.8 degrees, p < 0.01), and 3-months (0.6 vs 2.1 degrees, p = 0.02) post-surgery. Postoperative Knee Society scores were similar between groups.

Preliminary findings demonstrate robotic-arm assisted TKA is safe and efficacious with outcomes comparable, if not superior, to that of manually instrumented TKA.
Does the Use of a CT Based 3D Plan Improve Joint Balancing in Total Knee Arthroplasty? A Multi-Center Study
Authors: Zhang Jingwei , Bhowmik-Stoker Manoshi , Scholl Laura , Condrey Caitlin , Hitt Kirby , Marchand Kevin , Marchand Robert
Published: October 2019

Studies have shown that dissatisfaction following TKA may stem from poor component placement and iatrogenic factors related to variability in surgical execution. A CT-based robotic assisted system allows surgeons to dynamically balance the joint prior to bone resection. This study aimed to determine if this system could improve TKA planning, reduce soft tissue releases, minimize bone resection, and accurately predict component size.

Six hundred and sixty-six cases undergoing primary robotic assisted TKA we enrolled in a prospective, multicenter study. Seven surgeons participated from seven US centers. Patient demographics and intraoperative surgical details were collected. Initial and final 3-dimensional alignment, component position, bone resection depths, use of soft tissue releases, knee balancing gaps, and component size were collected intraoperatively. Descriptive statistics were applied to determine the changes in these parameters between initial and final values.

In this study, 513 varus knees, 86 valgus knees, and 26 neutral knees were captured and stratified for analysis. Native deformity ranged from 12 degrees of valgus to 19 degrees of varus. 85% of all patients in this study did not require a soft tissue release. Complex deformities who required a soft tissue release were corrected on average to 3.36 degrees while cases without releases were corrected to 1.1 degree on average. All surgeons achieved their planned sizes on the tibia and femur more than 97.5% of the time within one size, and 100% of the time within two sizes. Flexion and extension gaps during knee balancing were within 2mm (mean 1mm) for all knees.

New tools may allow for enhanced execution and predictable balance for TKA, which may improve patient outcomes. In this study, preoperative planning via CT scan allowed surgeons to assess bony deformities and subtly adjust component position to reduce soft tissue trauma. Patient follow up is needed to determine clinical outcomes.
Gap Deviation after Cementation in Computer Assisted Navigation TKA
Authors: Leelasestaporn Chumroonkiet , Tarnpichprasert Tomorn
Published: October 2019

INTRODUCTION

The outcome of knee replacement depended on alignment, balancing of soft tissue, symmetrical and

rectangular gaps adjustment, and accurate implant placement. Many techniques have been used to

improve these factors including navigator assisted knee replacement, which has precise bone cut

and accurate soft tissue balancing. However, cementation may change gaps and alignment that can

affect outcome of knee replacement.

OBJECTIVE

To compare gaps and alignment after cementation in computer assisted total knee replacement

MATERIAL AND METHODS

Prospective collecting data all cases performed computer assisted total knee replacement with

cruciate retaining - mobile bearing implant design. Gaps and mechanical axis was collected and

compered between complete trial prosthesis and final cementation.

RESULT

Lateral extension gap and flexion contracture significantly increase after cementation when

compared with trial implantation [0.6 mm (P = 0.021), 2.7o (P = 0.00)]. The mechanical axis was not

deviated after cementation (P = 1.00).

CONCLUSION

Cementation is able to influence gap and alignment. It may be useful to control and recheck gap and

alignment with navigation system during cementation. Clinical correlation needs further

investigation.
Navigation improves the ten to fifteen-year survival rate after total knee arthroplasty for severe coronal deformation. A French multicentric nationwide study
Authors: Jenny Jean-Yves , Saragaglia Dominique
Published: October 2019

The survival rate of navigation-assisted total knee arthroplasty was superior to conventionally implanted after 12 years for knees with initial severe coronal deformation when mechanical revision was considered as the end-point. Longer follow-up is required to prove superiority of any technique.
Depth Camera Augmented Fluoroscopy with Video Overlay
Authors: Hickey Matthew , Guy Pierre , Hodgson Antony J.
Published: October 2019

In many orthopedic surgeries, the surgeon relies on a C-arm fluoroscopy machine with the images usually displayed on a bedside monitor. The mental effort that surgeons expend transferring information from the imaging display back to the surgical site can lead to distraction causing errors that could directly influence quality of surgery. Depth Camera Augmented Fluoroscopy (DeCAF) uses an Intel RealSense depth camera to provide real-time visualization of the surgical site by overlaying x-ray images from the C-arm onto live video of the patient’s surface anatomy. Using geometric data acquired via the depth camera, the device facilitates transforming a real-time video feed aligned with the camera coordinate system to a perspective aligned with the x-ray source. The x- ray overlay is attained while restricting incursion on the surgeon’s work area and allowing the C-arm to be used in its normal position to minimize radiation exposure. DeCAF successfully facilitates an x-ray video overlay feature while eliminating key limitations such as size, radiation exposure and acquisition time associated with other similar devices. Future work will involve evaluating overlay accuracy, the addition of second depth camera to aid in filling in areas with missing details, and a design iteration involving bagging of the camera with a sterile cover to ensure compliance with asepsis requirements prior to evaluating the system in the operating room.
Ten years results of total hip arthroplasty using CT-based navigation system
Authors: Nakamura Nobuo , Sugano Nobuhiko
Published: October 2019

The purpose of the study is to investigate minimum ten years clinical results of primary and revision THA using CT-based navigation. Forty-nine primary THAs and 2 revision THAs were performed on 42 patients and followed for at least 10 years. The mean age at surgery was 58 years and the mean follow up was 130 months. During surgery, navigation was used for acetabular reaming and cup implantation in all cases. We evaluated Japanese Orthopaedic Association (JOA) clinical outcome scores, revision surgery and complications. In one primary THA case, navigation procedure was aborted because of registration failure. This case experienced femoral periprosthetic fracture at 4.5 years and dislocation at 8.5 years postoperatively. In another primary THA case, revision THA was performed because of aseptic loosening of cup at 4.5 years postoperatively. Except these two cases, there were no complications such as fracture, dislocation, infection, nerve palsy, deep vein thrombosis or loosening. Preoperatively, mean JOA clinical score was 44 points. Ten years postoperatively, it was improved to 96 points. When the aborted case is eliminated, there were no dislocations at ten years. The survivorship rate at ten years was 98% when revision surgery for any reason was considered as the end point. In conclusion, ten years clinical results of THA using CT-based navigation system were acceptable.
The Effect of the PCL on Kinematics as it Relates to Soft-Tissue Preservation from Robotic-Arm Assisted Surgery
Authors: Rajaravivarma Raga , Liarno Sally , Kaverina Tatyana , Donde Sonia , Sneddon Emily
Published: October 2019

The use of haptic-based robotic-arm assisted total knee arthroplasty (hRATKA) has demonstrated a decrease in soft tissue damage. Hampp et al. [4] compared the soft tissue damage in a cadaveric study between manual total knee arthroplasty (MTKA) and hRATKA and found that the hRATKA specimens had significantly less damage to the PCL than the MTKA specimens [4]. The purpose of this study is to look at the effect of the posterior cruciate ligament (PCL) on kinematics, as defined by anterior-posterior (AP) tibial translation, during stair climb. Using a 6 degree-of-freedom (6-DOF) joint motion simulator, the stair climb profile was run on four cadaveric knee specimens with the PCL intact and the PCL cut. In the PCL deficient condition, there was more posterior tibial motion than when the PCL was intact, and this was more noticeable during the high flexion portion of the profile. These findings speak to the importance of soft tissue preservation, and the development of haptic-based robotic-arm assisted TKA can help prevent soft tissue damage to the PCL.
Robotic-assisted Total Hip Arthroplasty May Reduce the Risk of Complications in Patients Younger than 35
Authors: Novikov David , Luthringer Tyler , Cizmic Zlatan , Mahure Siddharth , Eftekhary Nima , Davidovitch Roy , Vigdorchik Jonathan
Published: October 2019

Purpose: In younger patients during total hip arthroplasty, the presence of morphologic deformities, previous surgeries, and retained hardware, can pose technical challenges making reconstruction difficult. The purpose of our study is to assess the outcome of robotic-assisted THA compared to conventional THA in patients younger than 35 years old.

Methods: A retrospective analysis of 123 patients younger than 35 years old that underwent primary unilateral THA between January 2013 and April 2018 was conducted. Patients were divided into two cohorts: (1) robotic-assisted THA and (2) conventional-THA (c-THA). Demographics, operative details, and postoperative outcomes were carefully studied. Radiographic analysis included measurement of postoperative acetabular anteversion and inclination angles as well as postoperative leg length discrepancies. Chi square and unpaired student t-tests were performed for all categorical and continuous variables, respectively.

Results: Of the total 123 patients, 30 patients (32 hips) were in the robotic-THA cohort, and 93 patients (100 hips) were in the conventional-THA cohort. Patients in the robotic-THA cohort were younger (26.6±6.2 vs. 29.0±5.3; p=0.03), had a higher mean BMI (29.8±8.2 vs. 25.7±5.9; p=0.03) at surgery. The most common indication for THA was DDH and osteonecrosis. The acetabular component was positioned within Lewinnek’s safe zone more often in the robotic-THA cohort compared to the c-THA cohort (94% vs 65%; p<0.01) (Figures 1 and 2). Leg length discrepancies were similar between both cohorts. Patients in the c-THA group were more likely to experience clinically significant higher rates of dislocation (2.9% vs. 0), revision (6.8%), any postoperative complication (7.8%), and 90-day readmission (2.9) following THA.

Conclusion: Robotic THA can help improve outcomes in younger THA recipients. Future studies with larger cohorts and longer follow-up times should evaluate outcomes in this historically technically demanding patient population.
What factors influence surgeon cervical posture and perceived workload during TKA?
Authors: Scholl Laura , Kolisek Frank , Chen Antonia , Bhave Anil , Freedhand Adam , Hampp Emily , Alipit Vincent , Mont Michael
Published: October 2019

Orthopaedic surgery is a mentally and physically demanding procedure for surgeons. Studies reported 44-66% of surgeons surveyed have had a work-related injury attributed to poor surgeon posture. The purpose of this study was to understand how surgical variables may affect a surgeon’s posture and workload when performing TKA. Variables included: influence of level of surgical experience, type of surgical procedure, and specific surgical tasks.

Two experienced surgeons, with a median 22-years surgical experience, and 2 surgeons, currently in their fellowship training, each performed 3 manual TKAs (MTKA) and 3 robotic assisted TKAs (RATKA) using a cadaveric setup. Kinematic sensors were placed on the occiput and T3 to measure flexion of the head and neck. Surgeons were surveyed to assess their physical and mental effort using a 1-10 scale (1 being least effort).

Compared to the fellows, experienced surgeons had reduced occiput and T3 angles for MTKA (28.0 vs. 38.7°, 4.2 vs. 15.7°) and RATKA (18.0 vs. 29.2°, 4.8 vs. 13.2°) as well as reduced mental and physical effort. Considering surgical procedure, all surgeons had reduced occiput angles for RATKA compared to MTKA. Considering surgical task, surgical application (MTKA vs. RATKA) had greater influence on cervical angles for the fellows group.

All three factors influenced the surgeon’s posture and workload. Occiput angle was reduced by approximately 10° during RATKA, which is attributed to the surgeon standing in a more upright position, to visualize the robotic screen during cutting and trialing. Robotics may help newer surgeons better visualize knee balancing during TKA, easing the process of balancing and trialing.
Shadow Peak: Accurate Real-time Bone Segmentation for Ultrasound and Developmental Dysplasia of the Hip
Authors: Pandey Prashant , Quader Niamul , Mulpuri Kishore , Guy Pierre , Garbi Rafeef , Hodgson Antony J.
Published: October 2019

Confidence-weighted structured phase symmetry (CSPS) is a state-of-the-art bone seg- mentation technique for ultrasound (US), which has been recently proposed for automatic diagnosis for developmental dysplasia of the hip (DDH). However, CSPS relies on complex image phase feature analysis which is computationally expensive, and in our preliminary tests we have found it to be sometimes inaccurate. We evaluate a simpler alternative segmentation technique which we previously published, called Shadow Peak (SP), which uses intensity analysis to perform fast and accurate US bone segmentation. On average, SP segmentation ran 15 times faster for 2D US images, when tested on 15 hip images of pediatric patients. Furthermore, SP improves the segmentation F-score to 94%, compared to 72% when using CSPS segmentation.
Navigation improves the ten to fifteen-year survival rate after mobile bearing total knee arthroplasty. A French multicentric nationwide study
Authors: Jenny Jean-Yves , Saragaglia Dominique
Published: October 2019

The survival rate of navigation-assisted mobile bearing total knee arthroplasty after 13 years when mechanical revision was considered as the end-point was significantly improved when compared to conventionally implanted mobile bearing total knee arthroplasty. Longer follow-up is required to prove superiority of any technique.
What to Expect in Short-term Outcomes of “Challenging” Patients with Computer-Assisted Total Knee Arthroplasty?
Authors: Dai Yifei , Cui Quanjun , Bolognesi Michael , Wellman Samuel , Seyler Thorsten , Najmabadi Yassaman , Bolch Charlotte , Liu David
Published: October 2019

This study investigated if CAOS TKA cases in higher risk patients would impact the outcomes of surgery. An average of 14-month postoperative outcomes on 58 TKAs from a prospective multicenter study were analyzed. The patients were grouped into challenging and standard case groups according to the criteria of age, BMI, comorbidities, and alignment deformity. Both groups demonstrated significant postoperative improvement in all outcome measures. Compared to the standard patients, the challenging patients achieved significantly higher improvement after TKA in KSS Knee score, while demonstrating the same level of improvements in all other outcome measures. Similarly, the two groups generally exhibit equivalent postoperative outcomes. The data demonstrated consistent postoperative results by CAOS TKA irrespective of patient conditions.
All-in-one intraoperative 3D imaging and navigation on percutaneous vertebroplasty. Preliminary results on the first 51 patients
Authors: Tonetti Jérôme , Boudissa Mehdi , Kerschbaumer Gael , Prod'Homme Marc
Published: October 2019

Vertebroplasty (VP) is the gold standard for vertebral compression fracture (VCF) treatment. VP could be improved by using intra operative cone bean computed tomography (CBCT) although duration is largely increased. We report first series of 51 patients whom underwent VP integrating intraoperative navigation to CBCT, in order to cut down time consumption. During a 8 month period, 51 patients were prospectively enrolled. The mean age was 71 years old (36-94). There were 17 male and 35 female. We stored 65 VP (14 thoracic and 51 lumbar). After percutaneous pins fixation to the spinous process of the “Butterfly” acquisition reference frame, 180° rotation of the C-arm CBCT (Surgivisio®, eCential, Grenoble France) generated a 3D volume. Optically localized, sterile self- calibrated trocar was navigated in order to reach the vertebral body center by an unilateral pedicular approach. Cement (Vertaplex HV®, Stryker) was injected under fluoroscopic lateral view by the same machine, using standard 2D X-ray modes. Considering the 38 patients who underwent 1 level VP, mean time procedure was 00:30:09 [00:21:00 to 00:54:00; SD 00:10:23]. The mean DAP was 5,41318 Gy.cm2 and mean exposure duration 3,68 seconds. The mean efficient dose (E) was 1,32 mSv. In all cases cement placement was classified as excellent or mild, without any leakage. This new C-arm CBCT with integrated navigation is efficient to dramatically decrease operating time in comparison to literature (00:46:00 to 00:52:08). The reduction of radiation dose is already demonstrated in literature for navigated VP.
Assisted Preoperative Planning in Total Hip Arthroplasty to Reduce Leg Length Discrepancy
Authors: Esposito Paolo , Solitro Giovanni Francesco , Amirouche Farid M.L. , Fortuna Damiano , Pellegrino Arcangelo , Villecco Francesco
Published: October 2019

Preoperative planning is an integral part of total joint arthroplasty, aiming to restore the joint mimicking the native functionality (Choplin 2008).Dimensions of bone and prosthetic implants are usually evaluated by preoperative radiographs to restore leg length discrepancy and femoral offset (Amirouche et al 2015).Nevertheless, even when using dedicated software, the femoral component is precisely selected only in 34% of the cases, resulting in a significant variability in 50% of the patients with 10mm in postoperative leg length discrepancy (Strøm e Reikerås 2018) With the aim of reducing postoperative complications, in this work a computer algorithm has been developed that uses preoperative x-rays and performs automatic extraction of anatomical landmarks together with an automatic selection of the component that closely restore the native hip. In a first phase, the Fuzzy logic based algorithm extracts the axis of the femoral neck, the femoral axis of the middle diaphysis,both the trochanters and the center of the femoral head.Then,by checking the geometrical data of commercially available hardware selects the component closer to the native anatomy. In a second phase,by a kinematic approximation the algorithm uses the segmentation of the intramedullary canal to position the implant,assuming a press-fit insertion and thus anticipating potential contact region and, consequently, leg length discrepancy and offset. The algorithm has been tested on a set of x-ray images. The correlation diagram is used to determine the femur length bt means of the diameter of the femoral head. A sample of 16 femoral radiographs in Antero-posterior view was used to validate the algorithm. The head size was used to evaluate the error between the dimension calculated and the one manually measured on the radiograph, resulting in the order of + 2.00 mm.The prediction of the fixation by means of press-fit technique gives an average contact height of 21.49 mm and an angular deviation of 4.13 ° of the neck axis, applying a force of 9.25 kN (Sakai 2011).Compared to existing methods, the proposed algorithm allows to calculate the femoral sizes necessary for dimensioning the implant from 2D radiographs in the frontal view only and to predict the prosthesis-bone contact in terms of height and interference reached after hammering.It has to be noted that the study, based on coronal x-rays, does not actually account for pelvic tilt (Bono 2018), that will be include in a further research.
Towards a Commercial System for Intraoperative Manufacture of Patient-Specific Guides for Shoulder Arthroplasty
Authors: Darwood Alastair , Hurst Simon , Villatte Guillaume , Fenton Ryan , Tatti Fabio , El-Daou Hadi , Reilly Peter , Emery Roger , Rodriguez Y Baena Ferdinando
Published: October 2019

The accurate placement of orthopaedic implants according to a biomechanically derived preoperative plan is an important consideration in the long-term success of these interventions. Guidance technologies are widely described however, high cost, complex theatre integration, intraoperative inefficiency and functional limitations have prevented the widespread use. A novel, intraoperative mechatronics platform is presented, capable of the rapid, intraoperative manufacture of low-cost patient-specific guides. The device consists of a tableside robot with sterile drapes and some low cost, sterile disposable components. The robot comprises a 3D optical scanner, a three-axis sterile computer numerical control (CNC) drill and a two-axis receptacle into which the disposable consumables may be inserted. The sterile consumable comprises a region of rapidly setting moldable material and a clip allowing it to be reversibly attached to the tableside robot. In use, patient computed tomography (CT) imaging is obtained at any point prior to surgery and a surgical plan is created on associated software. This plan describes the axis and positioning of one or more guidewires which may, in turn, locate the prosthesis into position. Intraoperatively, osseous anatomy is exposed, and the sterile disposable is used to rapidly create a mould of the joint surface. Once set, the mould is inserted into the robot and an optical scan of the surface is taken followed by automatic surface registration, bringing the optical scan into the same coordinate frame of reference as the CT data and plan. The CNC drill is orientated such that the drill axis and position exactly matches the planned axis and position with respect to the moulded surface. A guide hole is drilled into the mould blank, which is removed from the robot and placed back into the patient with the moulded surface ensuring exact replacement. A wire is subsequently driven through the guide hole into the osseous anatomy in accordance with the preoperative plan. The guide blank may be slid off the wire and discarded allowing the procedure to continue in the normal manner. A Pre-clinical prototype robot was constructed and used to insert guide wires into a 12 cadaveric shoulder arthroplasty specimens according to a ‘pre-operative’ plan. A ‘postoperative’ CT scan was used to assess accuracy with respect to the ‘pre-operative’ plan. Initial average end to end accuracy was 1.2 mm with respect to planned vs achieved glenoid point of entry and 2.2deg version, 1.6deg inclination with respect to planned vs achieved wire angle. These data demonstrate accuracy within the bounds of relevant literature with a significant margin for potential improvement.
Robotic Arm Assisted Total Knee Arthroplasty: Addressing 1-12 Degrees Valgus Knees
Authors: Zhang Jingwei , Bhowmik-Stoker Manoshi , Scholl Laura , Condrey Caitlin , Marchand Kevin , Marchand Robert
Published: October 2019

The purpose of this work was to determine the number of soft tissue releases and component orientation of valgus cases performed with Robotic-Arm Assisted total knee arthroplasty (RATKA).

This study was a retrospective chart review of cases performed by a single surgeon from July 2016 to December 2017. 72 RATKA cases were defined as having a valgus deformity pre-operatively. Patient demographics and intraoperative surgical details were collected, including initial and final 3D component alignment, knee balancing gaps, full or partial releases. Post- operatively, radiographs, adverse events, and reduced WOMAC pain and KOOS Jr scores were collected at 6 months post-operatively.

Pre-operatively, knee deformities ranged from 1o to 12° with fixed flexion contracture. All knees were corrected within 2.5 degrees of mechanical neutral. Medial and lateral gaps were balanced in extension 100% of cases and flexion 93% of cases.

Radiographic evidence suggested well seated and well-fixed components. No revision and re- operation is reported. Patient reported outcomes measures collected at 6-month follow up indicated an improvement in WOMAC pain score from 9.6 to 3.2 and improvement in KOOS Jr from 44.7 to 74.4 points.

In this retrospective case review, soft tissue releases were not needed to address valgus knees ranging from 1-12° of deformity. The surgeon was able to balance the knee with bone resections and avoid disturbing the soft tissue envelope. While this study has a number of limitations, RATKA for valgus knees should continue to be investigated in a multicenter study.
The Impact of Workflow on Cutting Time for Partial Knee Arthroplasty
Authors: Hampp Emily , Scholl Laura , Haque Md , Wu Chunyan , Westrich Geoffrey , Mont Michael
Published: October 2019

To date, there are no studies aimed at characterizing the active cutting time for a robotic-assisted PKA procedure and the impact of workflow. This study quantified the active cutting time for three medial PKA workflows using the same robotic-assisted system.

Three surgeons each prepared six cadaveric knees for PKA with robotic-assisted technology using one of three workflows: A) burr-only, using a legacy cutting system and burr design; B) burr-only, using a new cutting system and burr design; or C) planar, using a new cutting system, burr design and saw. For a burr-only workflow, the femur and tibia were prepared with a burr. For a planar workflow, the femur and tibia were prepared with a burr and saw. The total mean trigger time to complete all femoral or tibial bony resections was measured and statistically compared between workflows using ANOVA and Tukey Pairwise Comparison.

There was statistically significant less time required to prepare the femur and tibia in B and C, compared to A (p≤0.05). Less time was required in C than B, but this was not statistically significant (p>0.05). Workflow A took an average of 429±104 seconds (range, 314 to 529 seconds), B took an average of 302±40 seconds (range, 244 to 363 seconds), and C took an average of 236±50 seconds (range, 196 to 332 seconds).

The new burr design, when used with both burr-only and planar workflows, has the potential to be more efficient (30 and 45% faster, respectively) compared to the legacy burr using the burr-only workflow, for a medial PKA. Bone resection time should be investigated in a clinical setting.
Does the use of Robotic Technology Improve Surgeon Ergonomic Safety during TKA?
Authors: Scholl Laura , Hampp Emily , Alipit Vincent , Chen Antonia , Mont Michael , Bhave Anil
Published: October 2019

Surgeon physical stress in the operating room is a known potential cause of musculoskeletal overuse injuries, specifically in surgeons who perform total knee arthroplasty (TKA). Injuries have been attributed to ergonomically challenging postures. This study compared surgeon lower back and shoulder posture between manual TKA (MTKA) and robotic assisted TKA (RATKA).

Two surgeons performed a total six MTKA and six RATKA on a set of cadaveric knees. Movement and EMG sensors were secured to each surgeon to monitor lower back and shoulder movements, as well as muscle activities. Data was analyzed and activities were assessed as low, medium, or high risk, providing a score between 0-lowest and 16-highest. Risk data was compared between MTKA and RATKA for three separate surgical tasks: 1-bone cut preparation & cutting (MTKA = placement of cutting jigs, bone cutting, RATKA = array placement, bone registration, bone cutting), 2-knee balancing and 3-trialing.

Overall, there were more high-risk shoulder than lower back activities in MTKA and RATKA. More high-risk movement and EMG stimulation were measured in the dominant shoulder than the non-dominant. When lower back and shoulder data were combined, highest risk task was bone cut preparation & cutting (MTKA: 13 vs. 6 vs. 6 and RATKA: 11 vs. 8 vs. 6), with a higher risk for MTKA than RATKA.

Poor posture can be a potential cause for surgeon work-related injuries. This study evaluated which tasks presented highest risk to surgeon ergonomic safety while performing TKA, and found lower overall ergonomics risk for performing RATKA vs. MTKA. Although this study provides data indicating reduced ergonomic risk with RATKA, additional studies in the operating room need to be performed.
Peak Active Hip Flexion Following Navigated Total Hip Arthroplasty.
Authors: Leonard Hollie , Ewen Alistair , Deep Kamal
Published: October 2019

The importance of accurate cup positioning during total hip arthroplasty (THA) to minimise post- operative complications has been well defined. However it remains unclear if following navigated THA there is a relationship between the active range of movement, the inclination and anteversion of the implant, and the theoretical range of movement as measured intra-operatively using imageless navigation. Fifteen male patients undergoing primary THA using the Orthopilot (Aesculap AG, Tuttlingen, Germany) imageless navigation system were recruited. The Orthopilot system flexion value was recorded. Three months post-THA patients underwent 3D biomechanical analysis (Vicon Motion Systems, Oxford, UK) during which patients performed a standing active hip flexion movement and a sitting task. Inclination and anteversion calculated according to Pradhan’s formula were taken from post-operative radiographs. There was no observed correlation with the theoretical hip flexion and the standing peak active or sitting peak hip flexion values in this series. However, Orthopilot flexion considers only the interaction of the implant components and not the soft tissues surrounding the hip joint which may limit clinical flexion. There does not appear to be any relationship between the inclination and anteversion angles and the range of movement observed post- operatively during a standing active hip flexion task and sitting task. It was observed that peak active hip flexion between the operated and non-operated limbs was not significantly different at three months, which indicates a good level of symmetry at this time point.