Preoperative Mapping in Unicompartmental Knee Arthroplasty Using Computed Tomography Scans Is Associated with Radiation Exposure and Carries High Cost

A Workflow-Efficient Approach to Pre- and Post-Operative Assessment of Weight-Bearing Three-Dimensional Knee Kinematics

BACKGROUND

Knee kinematics during daily activities reflect disease severity preoperatively and are associated with clinical outcomes after total knee arthroplasty (TKA). It is widely believed that measured kinematics would be useful for preoperative planning and postoperative assessment. Despite decades-long interest in measuring three-dimensional (3D) knee kinematics, no methods are available for routine, practical clinical examinations. We report a clinically practical method utilizing machine-learning-enhanced software and upgraded C-arm fluoroscopy for the accurate and time-efficient measurement of pre-TKA and post-TKA 3D dynamic knee kinematics.

METHODS

Using a common C-arm with an upgraded detector and software, we performed an 8-s horizontal sweeping pulsed fluoroscopic scan of the weight-bearing knee joint. The patient's knee was then imaged using pulsed C-arm fluoroscopy while performing standing, kneeling, squatting, stair, chair, and gait motion activities. We used limited-arc cone-beam reconstruction methods to create 3D models of the femur and tibia/fibula bones with implants, which can then be used to perform model-image registration to quantify the 3D knee kinematics.

RESULTS

The proposed protocol can be accomplished by an individual radiology technician in ten minutes and does not require additional equipment beyond a step and stool. The image analysis can be performed by a computer onboard the upgraded c-arm or in the cloud, before loading the examination results into the Picture Archiving and Communication System and Electronic Medical Record systems.

CONCLUSIONS

Weight-bearing kinematics affects knee function pre- and post-TKA. It has long been exclusively the domain of researchers to make such measurements. We present an approach that leverages common, but digitally upgraded, imaging hardware and software to implement an efficient examination protocol for accurately assessing 3D knee kinematics. With these capabilities, it will be possible to include dynamic 3D knee kinematics as a component of the routine clinical workup for patients who have diseased or replaced knees.

Bridging theory and practice: A comprehensive algorithm for imageless total knee arthroplasty

Total knee arthroplasty (TKA) is a surgical procedure to treat severe knee osteoarthritis. Among several techniques available for performing TKA, imageless TKA is known for achieving precise alignment while minimizing invasiveness. This work proposes a comprehensive algorithm for imageless TKA device to calculate the varus/valgus and flexion/extension angles, as well as resection depths for cutting planes at distal femur and proximal tibia. Moreover, the algorithm calculates the hip-knee-ankle (HKA) and flexion angles of the leg. Initially, the proposed algorithm was validated in a virtual environment using a CT-scanned bone model in Solidworks. Subsequently, for the real-world validation, a SoftBone model was resected with conventional intra and extramedullary rods and cross-checked with the proposed algorithm. For the third validation, another SoftBone model was resected with the proposed algorithm and cuts were measured with a vernier caliper. During this experiment, there was an error of approximately 1 mm for both femoral and tibial resection cases when using an infrared camera with an accuracy of ±0.5 mm. However, this error could be reduced using an infrared camera with higher accuracy.

Robotic-assisted total hip arthroplasty utilizing a fluoroscopy-guided system produced similar cup accuracy and precision relative to a computerized tomography-based robotic platform

Robotic assistance for total hip arthroplasty (THA) has been demonstrated to improve accuracy of acetabular cup placement relative to manual, unassisted technique. The purpose of this investigation was to compare the accuracy and precision between a fluoroscopy-based robotic total hip arthroplasty platform (FL-RTHA) and a computerized tomography-based (CT-RTHA) platform. The study included 98 consecutive FL-RTHA and 159 CT-RTHA procedures performed via direct anterior approach (DAA). All cases were performed for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Primary outcome variables included cup implantation accuracy and precision (variance). Implantation accuracy was calculated as the absolute value of the difference between pre-operative target cup angles (inclination and anteversion) and the same post-operative angles. Percentage placement in the Lewinnek safe zone was also measured for both cohorts. The FL-RTHA and CT-RTHA cohorts demonstrated a 1.2° difference in absolute values for cup inclination accuracy (4.6° ± 3.6 vs. 3.4 ± 2.7; p = 0.005), and no difference in absolute values for cup anteversion accuracy (4.7° ± 4.1 vs. 4.6 ± 3.4; p = 0.991). Cohorts demonstrated similar precision for cup inclination and anteversion placement parameters, as well as equivalent Lewinnek safe zone placement. The use of a fluoroscopy-based robotic assistance platform for primary DAA THA resulted in similar accuracy and precision of acetabular cup placement when compared to a CT-based robotic assistance system.

Identifying subgroups of patients that may benefit from robotic arm-assisted total knee arthroplasty: Secondary analysis of data from a randomised controlled trial

BACKGROUND

The aims were to assess whether a specific subgroup(s) of patients had a clinically significant benefit in their knee specific outcome or health-related quality of life (HRQoL) when undergoing robotic total knee arthroplasty (rTKA) when compared to manually performed TKA (mTKA).

METHODS

One hundred patients were randomised to either rTKA or mTKA, 50 to each group, of which 46 and 41 were available for functional review at 6-months, respectively. Subgroup analysis was undertaken for sex, age (<67-years versus ≥ 67-years), preoperative WOMAC score (<40 versus ≥ 40) and EQ-5D utility (<0.604 versus ≥ 0.604).

RESULTS

Male patients undergoing rTKA had a clinically and statistically significant greater improvement in WOMAC pain (mean difference (MD) 16.3, p = 0.011) at 2-months, function (MD 12.6, p = 0.032) and total score (MD 12.7, p = 0.030), and OKS (MD 6.0, p = 0.030) at 6-months. Patients < 67-years old undergoing rTKA had a clinically and statistically significant greater improvement in WOMAC pain (MD 10.3, p = 0.039) at 2-months, and function (MD 12.9, p = 0.040) and total (MD 13.1, p = 0.038) scores at 6-months. Patients with a preoperative WOMAC total score of < 40 points undergoing rTKA had a clinically and statistically significant greater improvement in WOMAC pain (MD 14.6, p = 0.044) at 6-months. Patients with a preoperative EQ-5D utility of <0.604 undergoing rTKA had a clinically and statistically significant greater improvement in WOMAC pain (MD 15.5, p = 0.011) at 2-months.

CONCLUSION

Patients of male sex, younger age, worse preoperative knee specific function and HRQoL had a clinically significantly better early functional outcome with rTKA when compared to mTKA.

Does robotic-assisted unicompartmental knee arthroplasty restore native joint line more accurately than with conventional instruments?

The study's primary aim is the restoration of native joint line in patients having robotic-assisted unicondylar knee arthroplasty and conventional unicondylar knee arthroplasty. Literature in the past has demonstrated that reducing the joint line can result in greater failure rates. This is a prospective cohort investigation of patients who had medial UKA between March 2017 and March 2022.All patient's pre-operative and post-operative radiological joint line assessments were examined by two observers by Weber's methods. Robotic-assisted UKA performed with hand-held image-free robots was compared to conventional UKA groups. The distal position of the femoral component was higher in Group B utilizing conventional tools than in Group A employing robotic-assisted UKA. This positional difference was statistically significant. The mean difference among the pre-operative and post-operative joint lines in Group A was 1.6 ± 0.49 (range 0.8 mm-2.4 mm), while it was 2.47 ± 0.51 (range 1.6 mm-3.9 mm) (p 0.005) in Group B. In Group A, a greater percentage of the subjects (64%) attained a femoral component position within two millimeters from the joint line, whereas just 18% in Group B did. When compared with the conventional UKA technique, the meticulous attention to detail and planning for ligament rebalancing when using the robotic-assisted UKA technique not solely enhance surgical precision for implant placing but additionally provides excellent native joint line restoration and balancing. For validation of its longevity and survivability, the cohort must be tracked for a longer period of time.

Robotic Arm-assisted versus Manual (ROAM) total knee arthroplasty: a randomized controlled trial

Aims

The primary aim was to assess whether robotic total knee arthroplasty (rTKA) had a greater early knee-specific outcome when compared to manual TKA (mTKA). Secondary aims were to assess whether rTKA was associated with improved expectation fulfilment, health-related quality of life (HRQoL), and patient satisfaction when compared to mTKA.

Methods

A randomized controlled trial was undertaken, and patients were randomized to either mTKA or rTKA. The primary objective was functional improvement at six months. Overall, 100 patients were randomized, 50 to each group, of whom 46 rTKA and 41 mTKA patients were available for review at six months following surgery. There were no differences between the two groups.

Results

There was no difference between rTKA and mTKA groups at six months according to the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) functional score (mean difference (MD) 3.8 (95% confidence interval (CI) -5.6 to 13.1); p = 0.425). There was a greater improvement in the WOMAC pain score at two months (MD 9.5 (95% CI 0.6 to 18.3); p = 0.037) in the rTKA group, although by six months no significant difference was observed (MD 6.7 (95% CI -3.6 to 17.1); p = 0.198). The rTKA group were more likely to achieve a minimal important change in their WOMAC pain score when compared to the mTKA group at two months (n = 36 (78.3%) vs n = 24 (58.5%); p = 0.047) and at six months (n = 40 (87.0%) vs n = 29 (68.3%); p = 0.036). There was no difference in satisfaction between the rTKA group (97.8%; n = 45/46) and the mTKA group (87.8%; n = 36/41) at six months (p = 0.096). There were no differences in EuroQol five-dimension questionnaire (EQ-5D) utility gain (p ≥ 0.389) or fulfilment of patient expectation (p ≥ 0.054) between the groups.

Conclusion

There were no statistically significant or clinically meaningful differences in the change in WOMAC function between mTKA and rTKA at six months. rTKA was associated with a higher likelihood of achieving a clinically important change in knee pain at two and six months, but no differences in knee-specific function, patient satisfaction, health-related quality of life, or expectation fulfilment were observed.

Equivalent radiation exposure with robotic total hip replacement using a novel, fluoroscopic-guided (CT-free) system: case-control study versus manual technique

Accurate and precise positioning of the acetabular cup remains a prevalent challenge in total hip arthroplasty (THA). Robotic assistance for THA has increased over the past decade due to the potential to improve the accuracy of implant placement. However, a common criticism of existing robotic systems is the requirement for preoperative computerized tomography (CT) scans. This additional imaging increases patient radiation exposure, as well as cost, and requires pin placement during surgery. The goal of this study was to analyze the radiation burden associated with a novel, CT-free robotic THA system compared to an unassisted manual THA approach (n = 100/arm). On average, the study cohort had a higher number of fluoroscopic images captured (7.5 vs. 4.3 images; p < 0.001), radiation dose (3.0 vs. 1.0 mGy; p < 0.001), and a longer duration of radiation exposure (18.8 vs. 6.3 s; p < 0.001), per procedure, than the control group. Additionally, no learning curve was detected by CUSUM analysis with respect to the number of fluoroscopic images taken during the adoption of the robotic THA system. While statistically significant, in comparison to published literature, the radiation exposure of the CT-free robotic THA system was comparable to that of unassisted manual THA approach and less than that of CT-based robotic approaches. Thus, the novel CT-free robotic system likely poses no clinically significant increase in radiation exposure to the patient compared to manual approaches.

[Translated article] Current situation of robotics in knee prosthetic surgery: A technology that has come to stay?

Robotic surgery is a surgical technique that is on the rise. The goal of robotic-assisted total knee arthroplasty (RA-TKA) is to provide the surgeon with a tool to accurately execute bone cuts according to previous surgical planning to restore knee kinematics and balance of soft tissue, being able to precisely apply the type of alignment that we choose. In addition, RA-TKA is a very useful tool for training. Within the limitations, there is the learning curve, the need for specific equipment, the high cost of the devices, the increase in radiation in some systems and that each robot is linked to a specific type of implant. Current studies show, with RA-TKA, variations in the alignment of the mechanical axis are reduced, postoperative pain is improved and earlier discharge is facilitated. On the other hand, there are no differences in terms of range of motion, alignment, gap balance, complications, surgical time or functional results.

Moving beyond radiographic alignment: applying the Wald Principles in the adoption of robotic total knee arthroplasty

The use of robotics in total knee arthroplasty (TKA) is growing at an exponential rate. Despite the improved accuracy and reproducibility of robotic-assisted TKA, consistent clinical benefits have yet to be determined, with most studies showing comparable functional outcomes and survivorship between robotic and conventional techniques. Given the success and durability of conventional TKA, measurable improvements in these outcomes with robotic assistance may be difficult to prove. Efforts to optimize component alignment within two degrees of neutral may be an attainable but misguided goal. Applying the "Wald Principles" of rationalization, it is possible that robotic technology may still prove beneficial, even when equivalent clinical outcomes as conventional methods, if we look beyond the obvious surrogate measures of success. Robotic systems may help to reduce inventory, streamline surgical trays, enhance workflows and surgical efficiency, optimize soft tissue balancing, improve surgeon ergonomics, and integrate artificial intelligence and machine learning algorithms into a broader digital ecosystem. This article explores these less obvious alternative benefits of robotic surgery in the field of TKA.

Robotic-Assisted Unicompartmental Knee Arthroplasty Reduces Components' Positioning Differences among High- and Low-Volume Surgeons

Robotic-assisted medial unicompartmental knee arthroplasty (mUKA) has been introduced to improve accuracy in implant positioning and limb alignment, overcoming the reported high failure rates of conventional UKA. Indeed, mUKA is a technically challenging procedure strongly related to surgeons' skills and expertise. The purpose of this study was to evaluate the likelihood of robotic-assisted surgery in reducing the variability of coronal and sagittal component positioning between high- and low-volume surgeons. We evaluated a prospective cohort of 161 robotic mUKA implanted between May 2018 and December 2019 at two high-volume robotic centers. Patients were divided into two groups: patients operated by "high-volume" (group A) or "low-volume" (group B) surgeons. We recorded intraoperative lower-limb alignment, component positioning, and surgical timing. Postoperatively, every patient underwent a radiographical protocol to assess coronal and sagittal femoral/tibial component alignment. Range of motion and other clinical outcomes were assessed pre- and 12 months postoperatively by using oxford knee score, forgotten joint score, and visual analog scale. Of 161 recruited knees, 149 (A: 101; B: 48) were available for radiographic analysis at 1 month, and clinical evaluation at 12 months. No clinical difference neither difference in mechanical alignment nor coronal/sagittal component positioning were found (p > 0.05). A significant difference was recorded in surgical timing (A: 57 minutes; B: 86 minutes; p < 0.05). No superficial or deep infections or other major complications have been developed during the follow-up. Robotics surgery in mUKA confirmed its value in improving the reproducibility of such technical procedure, with satisfactory clinical outcomes. Moreover, it almost eliminates any possible differences in component positioning, and lower limb alignment among low-and high- volume knee surgeons.

Is it prime time for robotic-assisted TKAs? A systematic review of current studies

INTRODUCTION

Less-than-optimum positioning of femoral and tibial components and improper soft tissue tension, with abnormal loads and reduced range of motion, may cause lower patient satisfaction rates. To reduce surgeon-related variables during TKA, technology-assisted TKA was introduced, including computer navigation and robotic-assisted surgery (RATKA). Although several studies show promising short- and long-term functional and radiological outcomes of RATKA, there are still concerns related to its absolute superiority over conventional TKA.

METHODS

This review aims to provide an updated insight into the most recent articles reporting on outcomes (functional, radiological, and complications) of RATKA through a systematic search of major databases. A comprehensive English literature search was performed by both authors through four databases (Embase, PubMed, Web of Science, and Scopus). The full text of the final eligible studies was evaluated for inclusion, resulting in 13 studies that are included in this review.

RESULTS

There were 2112 knees in the 13 studies, with a follow-up ranging from three months to 13 years; only three were randomized controlled trials (RCTs), and nine directly compared the results of RATKA with CTKA technique. Seven studies reported the operative time ranging from 76.8 to 156 min; six reported a longer operative time with RATKA. Length of hospital stay (LOS) was reported in six studies which ranged from 0.48 to 2.1 days; in four studies the LOS was shorter with RATKA. In seven of the nine studies comparing RATKA with CTKA, no difference in functional outcomes was found. Four out of six studies reported that the overall alignment had mechanical alignment within ±3° of neutral alignment in all RATKA patients with an HKA ranging from -0.3 to 1.8°. Only one study reported better radiological outcomes in the RATKA group. In six comparative studies, no difference was found in the incidence of complications between RATKA and CTKA.

CONCLUSION

Although robotic-assisted total knee arthroplasty is a promising technology that provides better component alignment and superior early functional outcomes, the justification for its widespread adoption needs more robust evidence through well-designed and better long-term studies demonstrating superior, predictable, and durable clinical results compared to conventional total knee arthroplasty techniques.

[Market overview: Robotic-assisted arthroplasty : Current robotic systems, learning curve and cost analysis]

Robotic-assisted arthroplasty has been rapidly entering clinical routine in recent years. The leading endoprosthesis manufacturers have all meanwhile placed robotic systems on the market, which, however, differ significantly from one another technically. Current systems are currently classified according to the degree of autonomy (active vs. semi-active vs. passive) and the data/image source (image-based: CT vs. X‑ray, imageless). Some systems already offer the possibility of robotic-assisted or navigated implantation of hip endoprostheses. In the following review article, the currently leading robotic systems will be presented and compared with regard to their characteristics. Furthermore, the analysis of the learning curves for the different systems, currently available cost analysis models and an outlook on future developments and challenges will be given.

Improved accuracy and reproducibility of a novel CT-free robotic surgical assistant for medial unicompartmental knee arthroplasty compared to conventional instrumentation: a cadaveric study

PURPOSE

Alignment errors in medial unicompartmental knee arthroplasty (UKA) predispose to premature implant loosening and polyethylene wear. The purpose of this study was to determine whether a novel CT-free robotic surgical assistant improves the accuracy and reproducibility of bone resections in UKA compared to conventional manual instrumentation.

METHODS

Sixty matched cadaveric limbs received medial UKA with either the ROSA^® Partial Knee System or conventional instrumentation. Fifteen board-certified orthopaedic surgeons with no prior experience with this robotic application performed the procedures with the same implant system. Bone resection angles in the coronal, sagittal and transverse planes were determined using optical navigation while resection depth was obtained using calliper measurements. Group comparison was performed using Student's t test (mean absolute error), F test (variance) and Fisher's exact test (% within a value), with significance at p < 0.05.

RESULTS

Compared to conventional instrumentation, the accuracy of bone resections with CT-free robotic assistance was significantly improved for all bone resection parameters (p < 0.05), other than distal femoral resection depth, which did not differ significantly. Moreover, the variance was significantly lower (i.e. fewer chances of outliers) for five of seven parameters in the robotic group (p < 0.05). All values in the robotic group had a higher percentage of cases within 2° and 3° of the intraoperative plan. No re-cuts of the proximal tibia were required in the robotic group compared with 40% of cases in the conventional group.

CONCLUSION

The ROSA^® Partial Knee System was significantly more accurate, with fewer outliers, compared to conventional instrumentation. The data reported in our current study are comparable to other semiautonomous robotic devices and support the use of this robotic technology for medial UKA.

LEVEL OF EVIDENCE

Cadaveric study, Level V.

Robotic-Assisted Versus Manual Unicompartmental Knee Arthroplasty: A Time-Driven Activity-Based Cost Analysis

BACKGROUND

The cost-effectiveness of robotic-assisted unicompartmental knee arthroplasty (RA-UKA) remains unclear. Time-driven activity-based costing (TDABC) has been shown to accurately reflect true resource utilization. This study aimed to compare true facility costs between RA-UKA and conventional UKA.

METHODS

We identified 265 consecutive UKAs (133 RA, 132 conventional) performed at a specialty hospital in 2016-2020. Itemized facility costs were calculated using TDABC. Separate analyses including and excluding implant costs were performed. Multiple regression was performed to determine the independent effect of robotic assistance on facility costs.

RESULTS

Due to longer operative time, RA-UKA patients had higher personnel costs and total facility costs ($2,270 vs $1,854, P < .001). Controlling for demographics and comorbidities, robotic assistance was associated with an increase in personnel costs of $399.25 (95% confidence interval [CI] $343.75-$454.74, P < .001), reduction in supply costs of $55.03 (95% CI $0.56-$109.50, P = .048), and increase in total facility costs of $344.27 (95% CI $265.24-$423.31, P < .001) per case. However, after factoring in implant costs, robotic assistance was associated with a reduction in total facility costs of $235.87 (95% CI $40.88-$430.85, P < .001) per case.

CONCLUSION

Using TDABC, overall facility costs were lower in RA-UKA despite a longer operative time. To facilitate wider adoption of this technology, implant manufacturers may negotiate lower implant costs based on volume commitments when robotic assistance is used. These supply cost savings appear to offset a portion of the increased costs. Nonetheless, further research is needed to determine if RA-UKA can improve clinical outcomes and create value in arthroplasty.

The Use of Computerized Tomography Scans in Elective Knee and Hip Arthroplasty—What Do They Tell Us and at What Risk?

The average background radiation exposure in the United States has nearly doubled over the previous quarter century, with almost all the increase derived from medical imaging. Nearly 2% of all cancers in the United States may be attributable to radiation from computerized tomography (CT) scans. Given the nondiagnostic nature of CT scans that are used in elective knee and hip arthroplasty today, special consideration should be given to the inherent risk of radiation exposure with routine use of this technology. Methods to decrease radiation exposure including modulating the settings of the CT machine and using alternative non-CT-based systems can decrease patient exposure to radiation from CT scans. The rapid evolution of CT technology in arthroplasty has allowed for expanded clinical applications, the benefits of which remain controversial.

Revision Total Knee Arthroplasty Using Robotic Arm Technology

Total knee arthroplasty (TKA) is a highly successful operation for the treatment of end-stage osteoarthritis of the knee. Increasing use of computer-assisted and robotic-assisted total joint arthroplasty has been shown to improve component position, with short-term studies demonstrating improved survivability in unicompartmental knee arthroplasty. Robotic-assisted technology has been shown to be helpful in revising unicompartmental knee arthroplasty to TKA, as well as hip fusion to total hip arthroplasty, but few have described revision of a primary TKA. This case report describes the use of robotic-assisted technology in revision TKA. Robotic assistance during revision TKA may improve component alignment and increase prosthesis longevity. Future research is needed to investigate the effects on survivorship and cost.

Concepts and techniques of a new robotically assisted technique for total knee arthroplasty: the ROSA knee system

INTRODUCTION

The ROSA (Robotic Surgical Assistant) Knee system (Zimmer Biomet, Warsaw, IN) for total knee arthroplasty (TKA) can be considered as collaborative robotics, where the surgeon remains in charge of the procedure and collaborates with a smart robotic tool, to perform the surgery with a high accuracy and reproducibility. The aim was to describe: (1) its concept and surgical technique; (2) its advantages and potential limits; (3) the early experience with this system.

MATERIALS AND METHODS

The goal during its development phase was to keep the surgeon active and at the center of the operation: the surgeon handles the saw and performs the cuts while the robotic arm places and holds the guide at the right place. The ROSA knee platform assists the surgeon for the distal femoral cut, the femoral component sizing and positioning, the tibial cut and the ligament balance. This robotic system has two options: image-based with 3D virtual model; or image-less, based on intraoperative landmarks acquisition. All the classic surgical techniques can be used: measured resection, gap balancing, functional alignment, kinematic alignment. Some techniques recently developed are more ROSA-specific: Robotic personalized TKA, ROSA-FuZion technique.

RESULTS

Its advantages as compared to other available systems include: radiographs in standing position, collaborative robotic system where the robot completes the surgeon skills, "off-the-shelf" implants, predictive robotic with concept of machine learning incorporated into the system. Two cadaveric studies have reported the high accuracy and reproducibility of this device. This robotic system is recent and currently no clinical series has enough follow-up to report clinical outcomes.

CONCLUSION

The ROSA knee system is a robotically assisted semi-autonomous surgical system with some specific characteristics. The aim of this collaborative robotic system is to improve the accuracy and reliability of the bone resections and the ligament balancing, without replacing the steps well performed by the surgeon.

Robot-Assisted Image-Guided Interventions

Image guidance is a common methodology of minimally invasive procedures. Depending on the type of intervention, various imaging modalities are available. Common imaging modalities are computed tomography, magnetic resonance tomography, and ultrasound. Robotic systems have been developed to enable and improve the procedures using these imaging techniques. Spatial and technological constraints limit the development of versatile robotic systems. This paper offers a brief overview of the developments of robotic systems for image-guided interventions since 2015 and includes samples of our current research in this field.

Incidental findings detected on preoperative CT imaging obtained for robotic-assisted joint replacements: clinical importance and the effect on the scheduled arthroplasty

OBJECTIVE

To determine the type and frequency of incidental findings detected on preoperative computed tomography (CT) imaging obtained for robotic-assisted joint replacements and their effect on the planned arthroplasty.

MATERIALS AND METHODS

All preoperative CT examinations performed for a robotic-assisted knee or total hip arthroplasty were obtained. This resulted in 1432 examinations performed between September 2016 and February 2020 at our institution. These examinations were initially interpreted by 1 of 9 fellowship-trained musculoskeletal radiologists. Using a diagnosis search, the examination reports were then reviewed to catalog all incidental findings and further classify as significant or non-significant findings. Demographic information was obtained. In those with significant findings, a chart review was performed to record the relevant workup, outcomes, and if the planned arthroplasty was affected.

RESULTS

Incidental findings were diagnosed in 740 (51.7%) patients. Of those with incidental findings, 41 (5.5%) were considered significant. A significant finding was more likely to be detected in males (P = 0.007) and on the hip protocol CT (P = 0.014). In 8 patients, these diagnoses resulted in either delay or cancelation of the arthroplasty. A planned total hip arthroplasty was more likely to be altered as compared to a knee arthroplasty (P = 0.018).

CONCLUSION

Incidental findings are commonly detected by radiologists on preoperative CT imaging obtained for robotic-assisted joint replacement. Several were valuable findings and resulted in a delay or even cancelation of the planned arthroplasty after the detection of critical diagnoses, which if not identified may have resulted in devastating outcomes.

Robotic-assisted unicompartmental knee arthroplasty: a review

Purpose

Presented here is an up-to-date review concerning robotic-assisted unicompartmental knee arthroplasty (rUKA), including its rationale, operative system, pros and cons.

Methods

We did a systematic research in electronic databases, including PubMed, Cochrane Library, Web of Science, and Embase up to March 30, 2020 to retrieve literature pertaining to rUKA. The search strategies “(robotic* AND knee arthroplasty OR knee replacement)” and “(knee arthroplasty OR knee replacement NOT total)” were used. Studies describing rUKA and clinical trials, dry bone or cadaveric researches regarding technologies, positioning, alignment, function, or survivorship of implants were included in this review. All retrieved studies were first browsed for eligibility on the basis of title and abstract, and the selected studies were further evaluated by reading full text for final inclusion.

Results

Robotic-assisted technology has been found to increase the accuracy of bone preparation and implant placement, reduce technical variability and outliers, and enhance reproduction of limb alignment. Additionally, early clinical outcomes were excellent, but mid-term follow-up showed no superiority in component survivorship. The potential drawbacks of the robotic-assisted technology include relatively-low time- and cost-effectiveness, development of some rUKA-related complications, and lack of support by high-quality literature.

Conclusion

This review shows that rUKA can decrease the number of outliers concerning the optimal implant positioning and limb alignment. However, due to absence of extensive studies on clinical outcomes and long-term results, it remains unclear whether the improved component positioning translates to better clinical outcomes or long-term survivorship of the implant. Nevertheless, since an accurate implant position is presumably beneficial, robotic-assisted technology is worth recommendation in UKA.

A clinical review of robotic navigation in total knee arthroplasty: historical systems to modern design

Robotic-assisted total knee arthroplasty (RA-TKA) has shown improved reproducibility and precision in mechanical alignment restoration, with improvement in early functional outcomes and 90-day episode of care cost savings compared to conventional TKA in some studies. However, its value is still to be determined.Current studies of RA-TKA systems are limited by short-term follow-up and significant heterogeneity of the available systems.In today's paradigm shift towards an increased emphasis on quality of care while curtailing costs, providing value-based care is the primary goal for healthcare systems and clinicians. As robotic technology continues to develop, longer-term studies evaluating implant survivorship and complications will determine whether the initial capital is offset by improved outcomes.Future studies will have to determine the value of RA-TKA based on longer-term survivorships, patient-reported outcome measures, functional outcomes, and patient satisfaction measures. Cite this article: EFORT Open Rev 2021;6:252-269. DOI: 10.1302/2058-5241.6.200071.

Robotic-assisted vs conventional surgery in medial unicompartmental knee arthroplasty: a clinical and radiological study

BACKGROUND

The use of unicompartmental knee arthroplasty (UKA) has increased and new technologies have been developed to improve patient survival and satisfaction, soft tissue balance, alignment, and component size. Robot-assisted systems offer an increase in surgical precision and accuracy. The purpose of this study is to evaluate the precision of component position using five radiological parameters in conventional and robotic-assisted medial UKA using the NAVIO system.

METHODS

A cohort study was designed for patients who underwent medial UKA between April 2017 and March 2019 in a single center. Patients were allocated in the conventional (UKA-C) or robotic-assisted (UKA-R) group. The variables analyzed were age, gender, affected knee side, length of hospital stay, surgical time, and radiological measurements such as anatomical medial distal femoral angle (aMDFA), anatomical medial proximal tibial angle (aMPTA), tibial slope, the sagittal femoral angle, and the component size. A target was defined for each measurement, and a successful UKA was defined if at least four radiological measures were on target after surgery. Also, patients' reported outcomes were evaluated using the Oxford Knee Score (OKS) and a numeric rating scale (NRS) for pain.

RESULTS

Thirty-four patients were included, 18 of them underwent UKA-R. The success rate for UKA in the UKA-R group was 87%; meanwhile, in the UKA-C group this was 28%, this difference was significant and powered (Fisher's exact test, p = 0.001; 1 - β = 0.95). Also, a 5-point difference in favor of the UKA-R group in the median OKS (p = 0.01), and a significantly lower median NRS for pain (p < 0.000) were found after surgery.

CONCLUSIONS

UKA-R achieved more precision in the radiological parameters' measure in this study. Also, UKA-R has a trend towards a better OKS and a lower NRS for pain at short-term follow-up.

New Technologies in Knee Arthroplasty: Current Concepts

Total knee arthroplasty (TKA) is an effective treatment for severe osteoarthritis. Despite good survival rates, up to 20% of TKA patients remain dissatisfied. Recently, promising new technologies have been developed in knee arthroplasty, and could improve the functional outcomes. The aim of this paper was to present some new technologies in TKA, their current concepts, their advantages, and limitations. The patient-specific instrumentations can allow an improvement of implant positioning and limb alignment, but no difference is found for functional outcomes. The customized implants are conceived to reproduce the native knee anatomy and to reproduce its biomechanics. The sensors have to aim to give objective data on ligaments balancing during TKA. Few studies are published on the results at mid-term of these two devices currently. The accelerometers are smart tools developed to improve the TKA alignment. Their benefits remain yet controversial. The robotic-assisted systems allow an accurate and reproducible bone preparation due to a robotic interface, with a 3D surgical planning, based on preoperative 3D imaging or not. This promising system, nevertheless, has some limits. The new technologies in TKA are very attractive and have constantly evolved. Nevertheless, some limitations persist and could be improved by artificial intelligence and predictive modeling.

Robotic-assisted Unicompartmental knee Arthroplasty optimizes joint line restitution better than conventional surgery

Purpose

To compare joint line restoration after unicompartmental knee arthroplasty (UKA) between conventional and robotic-assisted surgery. Previous studies have shown that joint line distalization can lead to higher failure rates. The hypothesis was that robotic-assisted UKA is associated with less femoral component distalization and a precise tibial cut, which allows a more anatomical restitution of the knee joint line.

Methods

Retrospective cohort study of patients undergoing medial or lateral UKA between May 2018 and March 2020. Preoperative and postoperative radiologic assessment of the joint line was performed by two observers, using three different methods, one for tibial slope and one for tibial resection. Robotic assisted UKA and conventional UKA groups were compared.

Results

Sixty UKA were included, of which 48 (77.42%) were medial. Robotic-assisted UKA were 40 (64.52%) and 22(35.48%) were conventional

The distalization of the femoral component was higher in the conventional group despite the method of measurement used In both Weber methods, the difference was statistically different: Conventional 2.3 (0.9 to 5.6) v/s Robotic 1.5 (− 1.1 to 4.1) (p =0.0025*). A higher proportion of patients achieved a femoral component position ≤ two millimeters from the joint line using robotic-assisted UKA compared to the conventional technique .

No statistical difference between robotic-assisted and conventional UKA was found in tibial resection and slope.

Conclusion

Robotic-assisted UKA shows a better rate of joint line restoration due to less femoral component distalization than conventional UKA. No difference was found in the amount of tibial resection between groups in this study.

Level of evidence

III

Management of failed UKA to TKA: conventional versus robotic-assisted conversion technique

Background

Failure of unicompartmental knee arthroplasty (UKA) is a distressing and technically challenging complication. Conventional conversion techniques (CCT) with rods and jigs have produced varying results. A robotic-assisted conversion technique (RCT) is an unexplored, though possibly advantageous, alternative. We compare our reconstructive outcomes between conventional and robotic methods in the management of failed UKA.

Methods

Thirty-four patients with a failed UKA were retrospectively reviewed. Patients underwent conversion total knee arthroplasty (TKA) with either a CCT or RCT. Seventeen patients were included in each group. All procedures were done by a single surgeon at a single institution, with a mean time to follow-up of 3.6 years (range, 1 to 12). The primary outcome measures were the need for augments and polyethylene thickness. Secondary outcome measures were complications, need for revision, estimated blood loss (EBL), length of stay, and operative time.

Results

The mean polyethylene thickness was 12 mm (range, 9 to 15) in the CCT group and 10 mm (range, 9 to 14) in the RCT groups, with no statistical difference between the two groups (P = 0.07). A statistically significant difference, however, was present in the use of augments. In the CCT group, five out of 17 knees required augments, whereas none of the 17 knees in the RCT group required augments (P = 0.04). Procedurally, robotic-assisted surgery progressed uneventfully, even with metal artifact noted on the preoperative computerized tomography (CT) scans. Computer mapping of the residual bone surface after implant removal was a helpful guide in minimizing resection depth. No further revisions or reoperations were performed in either group.

Conclusions

Robotic-assisted conversion TKA is technically feasible and potentially advantageous. In the absence of normal anatomic landmarks to guide conventional methods, the preoperative CT scans were unexpectedly helpful in establishing mechanical alignment and resection depth. In this limited series, RCT does not seem to be inferior to CCT. Further investigation of outcomes is warranted.

Evaluation of a novel lower radiation computed tomography protocol for assessment of tunnel position post anterior cruciate ligament reconstruction

Background

Anterior cruciate ligament (ACL) reconstruction is a common orthopaedic procedure. We developed a novel, low dose computed tomography (LDCT) protocol to assess tunnel position post-operatively. The effective radiation dose of this protocol is < 0.5millisieverts (mSv), which is significantly less than the 2 mSv dose for a conventional CT protocol. The aim of this study was to assess the accuracy of the LDCT protocol for determining tunnel position.

Methods

Twenty-six patients who underwent primary ACL reconstruction were included in the study. A LDCT scan was performed 6 weeks post-operatively. Femoral and tibial tunnel positions were measured on three dimensional (3D) reconstructions using previously validated techniques. Measurements were performed independently by three observers at two time points, 4 weeks apart.

Results

There was excellent intra- and inter-rater reliability for all measurements using the images obtained from the LDCT protocol. Intra-class correlation coefficient (ICC) values were > 0.9 for all measurements.

Conclusions

The LDCT protocol described in this study accurately demonstrates femoral and tibial tunnels post ACL reconstruction, while exposing the patient to a quarter of the radiation dose of a conventional CT. This protocol could be used by orthopaedic surgeons for routine post-operative imaging, in place of plain film radiographs.

A systematic review of imageless hand-held robotic-assisted knee arthroplasty: learning curve, accuracy, functional outcome and survivorship

The aim of this systematic review was to present and assess the quality of evidence for learning curve, component positioning, functional outcomes and implant survivorship for image-free hand-held robotic-assisted knee arthroplasty.Searches of PubMed and Google Scholar were performed in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. The criteria for inclusion was any published full-text article or abstract assessing image-free hand-held robotic knee arthroplasty and reporting learning curve, implant positioning, functional outcome or implant survival for clinical or non-clinical studies.There were 22 studies included. Five studies reported the learning curve: all were for unicompartmental knee arthroplasty (UKA) - no learning curve for accuracy, operative time was reduced after five to 10 cases and a steady surgical time was achieved after eight cases.There were 16 studies reporting accuracy: rate of outliers was halved, higher rate of joint line and mechanical axis restoration, supported by low root mean square error values.Six studies reported functional outcome: all for UKA, improvement at six to 52 weeks, no difference from manual UKA except when assessed for lateral UKA which showed improved clinical outcomes.Two studies reported survivorship: one reported an unadjusted revision rate of 7% at 20 months for medial UKA and the other found a 99% two-year survival rate for UKA.There was evidence to support more accurate implant positioning for UKA, but whether this is related to superior functional outcomes or improved implant survivorship was not clear and further studies are required. Cite this article: EFORT Open Rev 2020;5:319-326. DOI: 10.1302/2058-5241.5.190065.

CT planning studies for robotic total knee arthroplasty

Aims

The aim of this study was to analyze the true costs associated with preoperative CT scans performed for robotic-assisted total knee arthroplasty (RATKA) planning and to determine the value of a formal radiologist’s report of these studies.

Methods

We reviewed 194 CT reports of 176 sequential patients who underwent primary RATKA by a single surgeon at a suburban teaching hospital. CT radiology reports were reviewed for the presence of incidental findings that might change the management of the patient. Payments for the scans, including the technical and professional components, for 330 patients at two hospitals were also recorded and compared.

Results

There were 82 incidental findings in 61 CT studies, one of which led to a recommendation for additional testing. Across both institutions, the mean total payment for a preoperative scan was $446 ($8 to $3,870). The mean patient payment was $71 ($0 to $2,690). There was wide variation in payments between the institutions. In Institution A, the mean total payment was $258 ($168 to $264), with a mean patient payment of $57 ($0 to $100). The mean technical payment in this institution was $211 ($8 to $856), while the mean professional payment was $48 ($0 to $66). In Institution B, the mean total payment was $636 ($37 to $3,870), with a mean patient payment of $85 ($0 to $2,690).

Conclusion

The total cost of a CT scan is low and a minimal part of the overall cost of the RATKA. No incidental findings identified on imaging led to a change in management, suggesting that the professional component could be eliminated to reduce costs. Further studies need to take into account the patient perspective and the wide variation in total costs and patient payments across institutions and insurances. Cite this article: Bone Joint J 2020;102-B(6 Supple A):79–84.

Robotic-assisted Medial Unicompartmental Knee Arthroplasty: Options and Outcomes

Medial unicompartmental knee arthroplasty (UKA) has several benefits over total knee arthroplasty for the surgical treatment of isolated medial compartmental arthritis in the knee, including reduced surgical risk and postoperative morbidity, rapid recovery, more normal kinematics, greater patient satisfaction, and shorter hospitalization. Nonetheless, there is substantial concern about the higher revision rates and lower survivorship in UKA compared to those in total knee arthroplasty. Robotic assistance has been advanced to improve the precision of bone preparation, component alignment, and quantified ligament balance in UKA, with the ultimate goal of improving kinematics and implant survivorship. Two currently available semiautonomous robotic platforms have demonstrated improved accuracy, and emerging short-term follow-up has demonstrated satisfactory functional outcomes. Further studies will be needed to determine if these technologies indeed have a meaningful impact on patient outcomes and survivorship in the mid- to long term.

A novel handheld robotic-assisted system for unicompartmental knee arthroplasty: surgical technique and early survivorship

Technology, including robotics, has been developed for use in unicompartmental knee arthroplasty (UKA) to improve accuracy and precision of bone preparation, implant positioning, and soft tissue balance. The NAVIO™ System (Smith and Nephew, Pittsburgh, PA, United States) is a handheld robotic system that assists surgeons in planning implant positioning based on an individual patient’s anatomy and then preparing the bone surface to accurately achieve the plan. The surgical technique is presented herein. In addition, initial results are presented for 128 patients (mean age 64.7 years; 57.8% male) undergoing UKA with NAVIO. After a mean of follow-up period of 2.3 years, overall survivorship of the knee implant was 99.2% (95% confidence interval 94.6–99.9%). There was one revision encountered during the study, which was due to persistent soft tissue pain, without evidence of loosening, subsidence, malposition or infection. These initial results suggest a greater survivorship than achieved in the same follow-up time intervals in national registries and cohort studies, though further follow-up is needed to confirm whether this difference is maintained at longer durations.

Projective geometric model for automatic determination of X-ray-emitting source of a standard radiographic system

BACKGROUND AND OBJECTIVE

Currently, many orthopedic operations are planned by analyzing X-rays. The exact position of the focus is needed to calculate the real size of an object that is represented in conical projection, although in practice, this position is difficult to determine using current X-ray commercial systems. In this paper, a new geometric model is proposed in order to determine accurately, practically, and economically the location of the emitting source of commercial imaging systems using a single standard X-ray image.

METHOD

The method requires a specific reference locator object to be positioned in the visual field of radiographic image. Because this object cannot implement ideal geometric points, but instead works with small spheres, it was necessary to experimentally validate the proposed methodology. The implemented software that was developed to validate the model was used in four series of tests. In these tests, we studied the influence on the final result of: 1. the selection of a specific set of markers in radiography, 2. the focus position variation in relation to radiograph and 3. the possible rotated angle of locator object about Z axis.

RESULTS

The results for 164 tests that were performed with this software showed that the expected error for 99.5% of values ranges with maximum error of [-0.35%, +0.39%], which shows that the model is independent of the design of locator object and its position and orientation in the radiographic field. The software used to validate the proposed model has been found useful to verify its reliability, effectiveness, ease of implementation, and accuracy.

CONCLUSIONS

This model is effective to calculate the precise position of the X-ray focus of any standard radiographic system accurately.

Advances in Computer-Aided Technology for Total Knee Arthroplasty

Technology such as computer-assisted navigation systems, robotic-assisted systems, and patient-specific instrumentation has been increasingly explored during the past decade in an effort to optimize component alignment and improve clinical outcomes. Computer-assisted navigation accurately restores mechanical-axis alignment, but clinical outcome data are inconsistent. Computer-assisted navigation gap balancing has shown early promise in establishing mechanical-axis alignment with improved functional outcomes. Robotic-assisted systems more accurately restore component alignment when compared with computer-assisted navigation, but clinical outcomes have yet to be determined. Patient-specific instrumentation does not consistently improve alignment, accuracy, or patient outcomes. Studies demonstrating implant survivorship, cost-efficiency, and improved clinical outcomes and patient satisfaction are needed. [Orthopedics. 2017; 40(6):338-352.].

Robotically Assisted Unicompartmental Knee Arthroplasty with a Handheld Image-Free Sculpting Tool

Although unicompartmental knee arthroplasty may pose a lower risk of perioperative complications and achieve better functional outcomes than total knee arthroplasty, a high degree of accuracy of implant positioning and soft tissue balance are required to optimize durability and implant survivorship. First-generation robotic technology improved implant position compared with conventional methods. This article reviews the next-generation robotic technology, an image-free handheld robotic sculpting tool, which offers an alternative method for optimizing implant positioning and soft tissue balance without the need for preoperative computed tomography scans and with price points that make it suitable for use in outpatient surgery centers.