Causes and patterns of aborting a robot-assisted arthroplasty

Efficiency assessment of intelligent patient-specific instrumentation in total knee arthroplasty: a prospective randomized controlled trial

BACKGROUND

In total knee arthroplasty (TKA), the practical use of patient-specific instrumentation (PSI) has been reported previously with both advantage and disadvantage. The application of artificial intelligent (AI) forces overwhelmingly development of medical industries, while the impact of AI on PSI efficiency remains unknown. Thus, this study aimed to assess the efficiency of Intelligent-PSI (i-PSI) in TKA, compared with the conventional instrumentation-TKA (CI).

METHODS

102 late-stage OA patients who met inclusive criteria were recruited in this prospective randomized controlled trial and separated into two groups (i-PSI vs. CI). In both groups, an AI preoperative planning engine was applied for surgery decision making. In CI group, conventional instrumentation was applied for bony resection, while resection of i-PSI group was completed with i-PSI. A convolutional neural network was applied to automatically process computer tomography images and thus produced i-PSI. With the help of three-dimension printing, the workflow of production was largely simplified. AI-driven preoperative planning guided resection and alignment decisions. Resection measurement, perioperative radiography and perioperative clinical outcomes were analyzed to verify efficiency of i-PSI.

RESULTS

In resection outcomes, smaller deviation of lateral and medial distal femoral resection were found in i-PSI group than CI group (P = 0.032 and 0.035), while no difference was found in other resection planes. In radiography outcomes, postoperative coronal alignments of i-PSI group, including postoperative Hip-knee-ankle axis (HKA) (P = 0.025), postoperative HKA outliners (P = 0.042), Femoral coronal alignment (FCA) (P = 0.019) and Joint line convergence angle (JLCA) (P = 0.043) showed closer to neutral position than CI group. Moreover, Femoral sagittal alignment (FSA) of i-PSI group showed closer to neutral position than CI group(P = 0.005). No difference was found in other alignments. In clinical outcomes, i-PSI group seemed to cost more surgical time than CI group (P = 0.027), while others showed no differences between the two groups.

CONCLUSION

Intelligent Patient-specific Instrumentation in TKA achieved simplified production flow than conventional PSI, while also showed more accurate resection, improved synthesis position and limb alignment than conventional instrumentation. Above all, this study proved that i-PSI being an applicable and promising tool in TKA.

Robotics in Arthroplasty: Historical Progression, Contemporary Applications, and Future Horizons With Artificial Intelligence (AI) Integration

Robotic technology is increasingly utilized in surgical procedures to enhance precision, particularly in tasks demanding delicate maneuvers beyond human capabilities. Robotic orthopedic surgery emerges as a dynamic and compelling technology reshaping the landscape of surgical practice. This aids surgeons in achieving enhanced accuracy and reproducibility, ultimately aiming for improved patient outcomes. As of now, the majority of these systems are in a developed stage and are gradually gaining broader adoption. These systems have to show that they are user-friendly, are successful in clinical settings, and have a good cost-effectiveness ratio before they can be widely adopted in the field of surgery. In this review, we examine the evolution of robotics in orthopedic surgery, assess its current applications, and provide insights into the future trajectory of this technology, particularly in light of advances in artificial intelligence (AI) and machine learning (ML).

Robotic-assisted versus conventional total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Robotic knee arthroplasty procedures have emerged as a new trend, garnering attention from orthopedic surgeons globally. It has been hypothesized that the use of robotics enhances the accuracy of prosthesis positioning and alignment restoration. The objective of this study was to provide a high-level, evidence-based comparison between robotic total knee replacements and conventional methods, focusing on radiological and functional outcomes.

METHODS

We searched five databases from their inception until June 1, 2022, specifically targeting randomized controlled trials (RCTs) that compared the outcomes of robotic and conventional total knee replacements. We were interested in outcomes such as knee range of motion, clinical and function knee society scores, the Western Ontario and McMaster University score (WOMAC), the Hospital of Special Surgery score, complications, and radiological alignment. This review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes guidelines. We assessed the risk of bias using the revised Cochrane risk-of-bias tool for randomized trials (RoB 2).

RESULTS

Our search returned seven RCTs suitable for our analysis, which included a total of 1942 knees; 974 of these knees were implanted using robotic arms while the remaining 968 utilized jig-based knee systems. Our findings indicated that robotic knees had significantly better post-operative anatomical (OR - 0.82; 95% CI, - 1.027 to - 0.58, p value < 0.00001) and mechanical restoration (OR - 0.95; 95% CI, - 1.49 to - 0.41, p value < 0.0006). While knee range of motion (OR - 2.23; 95% CI - 4.89-0.43, p value 0.1) and femoral prosthesis position (OR - 0.98; 95% CI, - 2.03-0.08, p value 0.07) also favored robotic knees, these differences did not reach statistical significance. Both clinical and functional outcomes, as well as the rate of complications, were found to be statistically similar between the groups undergoing robotic and traditional knee replacement surgeries.

CONCLUSION

This meta-analysis indicates that robotic total knee replacements offer superior post-operative anatomical and mechanical alignment compared to conventional total knee replacements. Despite this, clinical and functional outcomes, as well as complication rates, were similar between the two. These findings should be considered in light of potential confounding factors. More randomized controlled trials with the latest robotic systems are needed to confirm any superior functional and clinical outcomes from robotic-assisted surgeries.

LEVEL OF EVIDENCE

I.

Complications and downsides of the robotic total knee arthroplasty: a systematic review

PURPOSE

The purpose of this systematic review is to describe the complications and downsides of robotic systems in total knee arthroplasty (TKA).

METHODS

A comprehensive search according to the PRISMA guidelines was performed across PubMed, MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, and Google Scholar from inception until December 2021. All articles of any study design directly reporting on complications and downsides of the robotic system in TKA were considered for inclusion. Risk of bias assessment was performed for all included studies using the Cochrane risk of bias and MINORS score.

RESULTS

A total of 21 studies were included, consisting of 4 randomized controlled trials, 7 prospective studies and 10 retrospective studies. Complications of the robotic system were pin-hole fracture, pin-related infection, iatrogenic soft tissue and bony injury, and excessive blood loss. While, downsides were longer operative duration, higher intraoperative cost, learning curve and aborting a robotic TKA due to different reasons. Iatrogenic injuries were more common in the active robotic system and abortion of the robotic TKA was reported only with active robotic TKA.

CONCLUSION

Robotic TKA is associated with certain advantages and disadvantages. Therefore, surgeons need to be familiar with the system to use it effectively. Widespread adoption of the robotic system should always be evidence-based.

LEVEL OF EVIDENCE

IV.

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.

[Development and clinical application of robot-assisted technology in traumatic orthopedics]

OBJECTIVE

To review and evaluate the basic principles and advantages of orthopedic robot-assisted technology, research progress, clinical applications, and limitations in the field of traumatic orthopedics, especially in fracture reduction robots.

METHODS

An extensive review of research literature on the principles of robot-assisted technology and fracture reduction robots was conducted to analyze the technical advantages and clinical efficacy and shortcomings, and to discuss the future development trends in this field.

RESULTS

Orthopedic surgical robots can assist orthopedists in intuitive preoperative planning, precise intraoperative control, and minimally invasive operations. It greatly expands the ability of doctors to evaluate and treat orthopedic trauma. Trauma orthopedic surgery robot has achieved a breakthrough from basic research to clinical application, and the preliminary results show that the technology can significantly improve surgical precision and reduce surgical trauma. However, there are still problems such as insufficient evaluation of effectiveness, limited means of technology realization, and narrow clinical indications that need to be solved.

CONCLUSION

Robot-assisted technology has a broad application prospect in traumatic orthopedics, but the current development is still in the initial stage. It is necessary to strengthen the cooperative medical-industrial research, the construction of doctors' communication platform, standardized training and data sharing in order to continuously promote the development of robot-assisted technology in traumatic orthopedics and better play its clinical application value.

Robotic arm-assisted arthroplasty: The latest developments

Joint arthroplasty is an effective method for treating end-stage joint lesions and damages. Robotic arm-assisted arthroplasty, a rapidly developing technology that combines navigation technology, minimally invasive technology, and precise control technology of the robotic arm, can achieve accurate preoperative planning, optimal selection of implants, minimally invasive surgery, precise osteotomy, and accurate placement of the artificial joint. It has the characteristics of high accuracy and stability, and thus is more and more widely used in the field of joint surgery. In this paper, we systematically reviewed the application and clinical efficacy of robotic arm-assisted technology in hip and knee arthroplasty to provide reference for its future promotion.

Navigation and robotics improved alignment compared with PSI and conventional instrument, while clinical outcomes were similar in TKA: a network meta-analysis

PURPOSE

To achieve the desired alignment more accurately and improve postoperative outcomes, new techniques such as computer navigation (Navigation), patient-specific instruments (PSI) and surgical robots (Robot) are applied in Total Knee Arthroplasty (TKA). This network meta-analysis aims to compare the radiological and clinical outcomes among the above-mentioned techniques and conventional instruments (CON).

METHODS

A PRISMA network meta-analysis was conducted and study protocol was published online at INPLASY (INPLASY202060018). Three databases (PubMed, EMBASE and Cochrane) were searched up to June 1, 2020. Randomised controlled trials (RCTs) comparing any two of the four techniques were included. A Bayesian network meta-analysis was performed focusing on radiological and clinical outcomes. The odds ratio (OR) or mean difference (MD) in various outcomes were calculated, and the interventions were ranked by the surface under the cumulative ranking area (SUCRA) value.

RESULTS

Seventy-three RCTs were included, with a total of 4209 TKAs. Navigation and Robot could significantly reduce the occurrence of malalignment and malposition compared with PSI and CON, and Navigation could obtain higher medium-and-long-term KSS knee scores than CON. Robot had the greatest advantage in achieving the desired alignment accurately, followed by Navigation; Navigation had the greatest advantage in the KSS score.

CONCLUSION

Navigation and Robot did improve the accuracy of alignment compared with PSI and conventional instrument in TKA, but the above four techniques showed no clinical significance in postoperative outcomes.

LEVEL OF EVIDENCE

I.

Robotics in orthopaedic surgery: why, what and how?

INTRODUCTION

Robotics applied to orthopedics has become an interesting topic both from the surgical point of view and the engineering one. The main goal of those systems is the enhancement of joint arthroplasty surgery, providing the robotic support to precisely and accurately prepare the bone, restore the limb alignment and the physiological kinematics of the joint. Various robotic systems are currently available on the market, each addressing specific kind of surgeries and characterized by a series of specific features that may involve different requirements and/or modus operandi.

MATERIAL AND METHODS

An overview of these devices was performed, addressing the different categories in which robots are subdivided in terms of: operations performed, requirements and level of interaction of the surgeon. The main models currently available on the market were addressed and relative studies in the literature were reported and compared, to highlight the benefits and drawbacks of the different technologies.

RESULTS

The different robotic systems were subdivided in: open/closed platform, image-based/imageless and active/passive/semi-active. Regardless of the typology of robotic system, the main aim is to improve precision and accuracy of the operation. It is to be noted that, regardless of the typology of robotic system, the surgeon is still in charge of the planning and approval of the operation: only the precise and consistent execution of his directives is entrusted to the robot. The positive factors have however to be weighed against the fact that robotic systems involve an important initial investment and most of the times require the surgeons and the staff to learn how to operate them (with a learning curve differing from system to system).

CONCLUSIONS

Each surgeon, when considering if and which robotic system to adopt, has to properly evaluate the different benefits and drawbacks involved to find the surgical robot that fits his needs the best.

The current state of robotics in total knee arthroplasty

Robotic total knee arthroplasty (TKA) has demonstrated improved component positioning and a reduction of alignment outliers with regard to pre-operative planning.

Early robotic TKA technologies were mainly active systems associated with significant technical and surgical complications.

Current robotic TKA systems are predominantly semi-active with additional haptic feedback which minimizes iatrogenic soft tissue injury compared to conventional arthroplasty and older systems.

Semi-active systems demonstrate advantages in terms of early functional recovery and hospital discharge compared to conventional arthroplasty.

Limitations with current robotic technology include high upfront costs, learning curves and lack of long-term outcomes.

The short-term gains and greater technical reliability associated with current systems may justify the ongoing investment in robotic technology.

Further long-term data are required to fully ascertain the cost-effectiveness of newer robotic systems.

Cite this article: EFORT Open Rev 2021;6:270-279. DOI: 10.1302/2058-5241.6.200052

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.

Is robotic-assisted unicompartmental knee arthroplasty a safe procedure? A case control study

PURPOSE

The hypotheses were that firstly there is few early specific complications due to the use of a robotic-assisted system for unicompartimental knee arthroplasty (UKA), and secondly there are less revisions and complications after robotic-assisted UKA than after conventional UKA.

METHODS

200 robotic-assisted UKA (175 patients) and 191 conventional UKA (179 patients) were performed between 2013 and 2018 from the same center. Revisions, intraoperative and postoperative complications, functional and radiological results were collected at the most recent follow-up.

RESULTS

At the most recent follow-up (≥ 1 year), revision rates were 4% (n = 8/200) for robotic-assisted UKA and 11% (n = 21/191) for conventional UKA (p = 0.014). Reoperation rates without implant removal were comparable in the robotic and conventional group (7.3% vs 8.6%). Complication rates for stiffness (4.7% vs 4.2%) and infection (1% vs 1.6%) were comparable in both groups. There was no specific complication related to the robotic-assisted system (no soft tissue or bone lesion caused by the use of the robotic-assistance and no complication related to the use of navigation pins). The KSS function scores were higher following robotic-assisted UKA (p = 0.01). Satisfaction rates and contralateral OA were comparable in the two groups.

CONCLUSION

No complications due to the robotic-assisted system were found in this study. There was no difference in the general complications rate between both groups. Robotic-assisted UKA has a lower revision rate compared to conventional technique UKA at the short-term follow-up.

LEVEL OF EVIDENCE

III.

CLINICAL RELEVANCE

This is the first paper comparing revision rate and clinical outcome between UKA performed using the NAVIO robotic system and a conventional technique and searching for specific complication related to the use of the NAVIO robotic system.

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.

Clinical value of CT-based patient-specific 3D preoperative design combined with conventional instruments in primary total knee arthroplasty: a propensity score-matched analysis

Purpose

To evaluate the operation and early clinical effect in primary total knee arthroplasty (TKA) about the novel combination of CT-based patient-specific three-dimensional (3D) preoperative design and conventional osteotomy instruments, compared with the conventional method.

Methods

After a 1:1 propensity score-matching (PSM), patients were matched to the novel technique group and the conventional group, 109 cases in each group. The conventional group adopted a preoperative design based on a full-length radiograph (FLX) and received TKA with conventional osteotomy instruments. The novel technique group used a CT-based patient-specific 3D preoperative design combined with conventional osteotomy instruments; during the surgery, the femoral entry point, femoral valgus osteotomy angle, the fix point of tibial plateau extramedullary guide pin, and the position of tibial extramedullary positioning rod were accurately selected according to the preoperative 3D design to ensure accurate intraoperative implementation. The lower limb alignment, component position, operation time, tourniquet time, hospital stay, blood loss volume, incidence of postoperative complications, visual analog scale (Vas) score, and New Knee Society Score System (NEW-KSS) at 1 day before operation and 1, 6, and 12 months after operation were recorded and compared.

Results

The novel technique group was significantly better than the conventional group in controlling lateral tibial component angle (LTC) (P < 0.001), and the novel technique group had lower percentages of hip-knee-ankle angle (HKA) outliers (P < 0.001) and overcorrection (P = 0.003). The operation time, tourniquet time, and hospital stay of the novel technique group was shorter (P < 0.05). In 1 month after the operation, the novel technique group achieved a significantly better VAS score (P < 0.05), but a similar NEW-KSS score (P > 0.05) when compared with the conventional group. But in 6 and 12 months after surgery, no statistical differences were seen in the above two scores (P > 0.05).

Conclusion

The novel technique of CT-based patient-specific 3D preoperative design combined with conventional instruments can improve the accuracy of osteotomy in primary total knee arthroplasty, with benefits of significantly reducing pain and rapid recovery during the early postoperative period, but having no obvious effect on outcome after a 1-year follow-up.

Current concepts in robotic total hip arthroplasty

INTRODUCTION

Total hip replacement provides mostly fair functional and clinical results. Many factors play an essential role in hip stability and long-term outcomes. Surgical positioning remains fundamental for obtaining accurate implant fit and prevent hip dislocation or impingement. Different categories of robotic assistance have been established throughout the previous years and all of the technologies target accuracy and reliability to reduce complications, and enhance clinical outcomes.

MATERIALS AND METHODS

An overview is proposed over the principles of robotic assistance in hip arthroplasty surgery. Accuracy, reliability, management of the bone stock, clinical outcomes, constraints and limits of this technology are reported, based on recent literature.

RESULTS

Potential advantages regarding pre-operative planning accuracy, cup positioning, maintenance of the center of rotation, preservation of an adequate bone stock nay clinical short- and mid-term outcomes are balanced with some reported disadvantages and limits like hip anatomical specificity, cost-effectiveness, engineering dependence.

DISCUSSION

The use of robotic-assisted THA presents clear and evident benefits related to accurate implant positioning and maintenance of a minimal bone while allowing. For some authors, an early improvement in functional results and patient's recovery. This technology demonstrated a shorter surgical time and a short learning curve required to optimize its use and this technology presents promising outcomes and results and potential use in routine clinical application but its limitation of use is still present especially the cost of the robot, the need for the presence of an engineer during the surgery, its availability of use in all hospitals as well as the difficulty presented in dysplastic or dysmorphic hip joints.

Computer-Assisted Orthopedic and Trauma Surgery

BACKGROUND

There are many ways in which computer-assisted orthopedic and trauma surgery (CAOS) procedures can help surgeons to plan and execute an intervention.

METHODS

This study is based on data derived from a selective search of the literature in the PubMed database, supported by a Google Scholar search.

RESULTS

For most applications the evidence is weak. In no sector did the use of computer-assisted surgery yield any relevant clinical or functional improvement. In trauma surgery, 3D-navigated sacroiliac screw fixation has become clinically established for the treatment of pelvic fractures. One randomized controlled trial showed a reduction in the rate of screw misplacement: 0% with 3D navigation versus 20.4% with the conventional procedure und 16.6% with 2D navigation. Moreover, navigation-assisted pedicle screw stabilization lowers the misplacement rate. In joint replacements, the long-term results showed no difference in respect of clinical/functional scores, the time for which the implant remained in place, or aseptic loosening.

CONCLUSION

Computer-assisted procedures can improve the precision of certain surgical interventions. Particularly in joint replacement and spinal surgery, the research is moving away from navigation in the direction of robotic procedures. Future studies should place greater emphasis on clinical and functional results.

Mid-to Long-Term Survival of Total Knee Arthroplasty in Hemophilic Arthropathy

While satisfactory results have been reported during short-to mid-term follow-up assessments of hemophilic patients who have undergone total knee arthroplasty (TKA), limited literature focusing on long-term survival following TKA exists to date. As part of this investigation, a consecutive series of 78 TKAs in 56 patients with hemophilic arthropathy was reviewed. The mean patient age at the time of operation was 38.7 years old and the mean length of follow up was 10.2 years. Clinical and radiologic outcomes, quality of life, complications, and long-term survivorship of TKA were evaluated. At the latest point of follow up, the average American Knee Society (AKS) knee and function scores had improved from 32.1 to 85.7 points and 41.5 to 83.3 points, respectively. Moreover, the average range of motion (ROM) was significantly increased from 64.2° preoperatively to 84.2° postoperatively. The physical and mental Short Form-36 results were also significantly improved at the latest point of follow up. Postoperative complications appeared in 12 knees (15.4%). The readmission rate in the 30 days after discharge was 6.4%. Revision TKA was performed in three knees for periprosthetic joint infection (n = 2 knees) and tibial component loosening (n = 1 knee). The Kaplan-Meier 10- and 13-year prosthesis survival rates were 97.1% and 93.2%, respectively. The current study suggests that the mid-to long-term results of TKA in patients with hemophilic arthropathy are favorable, with successful long-term prosthesis survival achievable in most cases.

Robotic-assisted total knee arthroplasty is comparable to conventional total knee arthroplasty: a meta-analysis and systematic review

BACKGROUND

Total knee arthroplasty (TKA) is a successful procedure in managing end-stage arthritis when non-operative treatments fail. New technologies such as robotic TKA (rTKA) have been developed to improve the accuracy of prosthesis implantation. While short-term cohort studies on rTKA have shown excellent results, the evidence comparing between rTKA and conventional TKA (cTKA) is not yet well established. This meta-analysis aims to compare the efficacy and safety of rTKA versus cTKA in terms of clinical outcomes, radiographic results, complications, peri-operative parameters and costs.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies comparing between rTKA and cTKA were extracted and analyzed.

RESULTS

Eighteen studies were included in this review, consisting of 2234 rTKA and 4300 cTKA. Robotic TKA led to a more precise prosthesis implantation with significantly fewer outliers in the mechanical axis (p < 0.001), femoral coronal (p = 0.002) and tibial sagittal (p = 0.01) alignments. Only the Hospital for Special Surgery (HSS) (p < 0.001) score at final follow-up was significantly better in rTKA than cTKA. rTKA also had a lower mean blood loss (p < 0.001) despite a longer mean operation time (p = 0.006). There were no statistically significant difference in terms of other clinical outcome measures, range of motion and complications.

CONCLUSION

Both rTKA and cTKA are reliable and safe to perform. However, rTKA is capable of achieving superior alignment in several axes, lower mean blood loss and this may lead to marginally better clinical outcomes than cTKA.

EVIDENCE LEVEL

Level II, Meta-analysis of non-homogeneous studies.

Robots in the Operating Room During Hip and Knee Arthroplasty

PURPOSE OF THE REVIEW

The utilization of technology has increased over the last decade across all surgical specialties. Robotic-assisted surgery, among the most advanced surgical technology, applied to hip and knee arthroplasty has experienced rapid growth in utilization, surgical applications, and robotic platforms. The goal of this study is to provide a comprehensive review of the most commonly utilized robotic platforms for hip and knee arthroplasty and the most up to date literature on the benefits and limitations of robotic arthroplasty.

RECENT FINDINGS

Studies consistently demonstrate that that robotic-assisted surgery during total hip arthroplasty (THA), total knee arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA) improves component position and alignment. There is also growing evidence that robotic-assisted UKA improves clinical outcomes and implant survivorship and, therefore, may be cost-effective. However, there remains to be convincing evidence that robotic-assisted arthroplasty improves clinical outcome measures or reduces revision rates for THA and TKA. Potential disadvantages of robotic arthroplasty remain, including a learning curve, potential for additional radiation exposure preoperatively, and the financial costs. Robotic hip and knee arthroplasty remains attactive as studies show that it consistently improves implant position and alignment over conventional techniques. There is growing evidence that robotic UKA may improve patient outcomes and reduce revision rates, but further study is needed. In addition, further and longer-term studies are needed to determine if improved component position and alignment in TKA and THA leads to improved clinical outcomes and reduced revision rates.

Low rate of iatrogenic complications during unicompartmental knee arthroplasty with two semiautonomous robotic systems

BACKGROUND

Intraoperative complications due to utilization of robotic assistance during unicompartmental knee arthroplasty have not been reported. While inadvertent soft tissue injury has been reported during total knee and hip arthroplasty with autonomous style robotic systems, the incidence of these problems with semiautonomous (i.e. surgeon-driven) systems is unknown.

METHODS

We report on a series of 1064 consecutive unicompartmental knee arthroplasties performed by one surgeon with either one of two commercially available semiautonomous robotic systems.

RESULTS

There were no soft tissue, bone injuries or other complications related to the use of the robotic bone preparation method. Six complications related to the use of standard computer navigation pins occurred (0.6%) - one pseudoaneurysm of a branch of the tibialis anterior artery, one tibial metaphyseal stress fracture, and four areas of pin site irritation/superficial infection that resolved with a short course of oral antibiotics.

CONCLUSION

Current semiautonomous robotic methods are safe, with few complications using meticulous surgical techniques.

A review of the evolution of robotic-assisted total hip arthroplasty

INTRODUCTION

Total hip arthroplasty (THA) is currently a very successful operation but continues to evolve as we try to perfect techniques and improve outcomes for our patients. Robotic hip surgery (RHS) began with the 'active' ROBODOC system in the 1980s. There were drawbacks associated with the original ROBODOC and most recently, the MAKO robot was introduced with early promising results.

AIM

The aim of this paper is to provide an up-to-date review surrounding this area and discuss the pros and cons of this technique.

METHODS

A literature review searching Medline, Embase, Ovidsp, Cochrane library, pubmed database and google scholar was performed searching keywords including: 'Robotic hip surgery', 'Robotic orthopaedic surgery', 'Computer assisted hip surgery', 'robotic arthroplasty', and 'computer assisted orthopaedic surgery'.

CONCLUSION

Robotic hip surgery aims to tackle the limitations of the human factor in surgery by promising reproducible and reliable methods of component positioning in arthroplasty surgery. However, as orthopaedic surgeons, we must critically appraise all new technology and support the use providing there is sound robust evidence backing it.

Efficacy and reliability of active robotic-assisted total knee arthroplasty compared with conventional total knee arthroplasty: a systematic review and meta-analysis

Background

In the field of prosthetics, the ultimate goal is to improve the clinical outcome by using a technique that prolongs the longevity of prosthesis. Active robotic-assisted total knee arthroplasty (TKA) is one such technique that is capable of providing accurate implant position and restoring mechanical alignment. Although relevant studies have been carried out, the differences in the efficacy and reliability between active robotic-assisted TKA and conventional arthroplasty have not yet been adequately discussed.

Methods

We referenced articles, including randomised controlled trials and comparative retrospective research, from PubMed, Embase, Cochrane Library and Web of Science, in order to compare active robotic-assisted TKA with the conventional technique. Data extraction and quality assessment were conducted for each study. Statistical analysis was performed using Revman V. 5.3.

Results

Seven studies with a total of 517 knees undergoing TKA were included. Compared with conventional surgery, active robotic TKA showed better outcomes in precise mechanical alignment (mean difference, MD: − 0.82, 95% CI: −1.15 to − 0.49, p < 0.05) and implant position, with lower outliers (p < 0.05), better functional score (Western Ontario and McMaster University, Knee Society Score functional score) and less drainage (MD: − 293.28, 95% CI: − 417.77 to − 168.79, p < 0.05). No significant differences were observed when comparing the operation time, range of motion and complication rates.

Conclusion

The current research demonstrates that active robotic-assisted TKA surgeries are more capable of improving mechanical alignment and prosthesis implantation when compared with conventional surgery. Further studies are required to investigate the potential benefits and long-term clinical outcomes of active robotic-assisted TKA.

An assessment of early functional rehabilitation and hospital discharge in conventional versus robotic-arm assisted unicompartmental knee arthroplasty: a prospective cohort study

AIMS

The objectives of this study were to compare postoperative pain, analgesia requirements, inpatient functional rehabilitation, time to hospital discharge, and complications in patients undergoing conventional jig-based unicompartmental knee arthroplasty (UKA) versus robotic-arm assisted UKA.

PATIENTS AND METHODS

This prospective cohort study included 146 patients with symptomatic medial compartment knee osteoarthritis undergoing primary UKA performed by a single surgeon. This included 73 consecutive patients undergoing conventional jig-based mobile bearing UKA, followed by 73 consecutive patients receiving robotic-arm assisted fixed bearing UKA. All surgical procedures were performed using the standard medial parapatellar approach for UKA, and all patients underwent the same postoperative rehabilitation programme. Postoperative pain scores on the numerical rating scale and opiate analgesia consumption were recorded until discharge. Time to attainment of predefined functional rehabilitation outcomes, hospital discharge, and postoperative complications were recorded by independent observers.

RESULTS

Robotic-arm assisted UKA was associated with reduced postoperative pain (p < 0.001), decreased opiate analgesia requirements (p < 0.001), shorter time to straight leg raise (p < 0.001), decreased number of physiotherapy sessions (p < 0.001), and increased maximum knee flexion at discharge (p < 0.001) compared with conventional jig-based UKA. Mean time to hospital discharge was reduced in robotic UKA compared with conventional UKA (42.5 hours (sd 5.9) vs 71.1 hours (sd 14.6), respectively; p < 0.001). There was no difference in postoperative complications between the two groups within 90 days' follow-up.

CONCLUSION

Robotic-arm assisted UKA was associated with decreased postoperative pain, reduced opiate analgesia requirements, improved early functional rehabilitation, and shorter time to hospital discharge compared with conventional jig-based UKA.

Pros and Cons: A Balanced View of Robotics in Knee Arthroplasty

In both unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA), compared with conventional techniques robotic technology has been shown to optimize the precision of bone preparation and component alignment, reducing outliers and increasing the percentage of components aligned within 2° or 3° of the target goal. In addition, soft tissue balance can be quantified through a range of motion in UKA and TKA using the various robotic technologies available. Although the presumption has been that the improved alignment associated with robotics will improve function and implant durability, there are limited data to support that notion. Based on recent and emerging data, it may be unreasonable to presume that robotics is necessary for both UKA and TKA. In fact, despite improvements in various proxy measures, the precision of robotics may be more important for UKA than TKA, although if system costs and surgical efficiencies continue to improve, streamlining perioperative processes, reducing instrument inventory, and achieving comparable outcomes in TKA may be a reasonable goal of robotic surgery.

Fourteen Year Follow-Up of Randomized Clinical Trials of Active Robotic-Assisted Total Hip Arthroplasty

BACKGROUND

Active robotic total hip arthroplasty (THA) has been used clinically for over 20 years, but long-term results have never been studied. The aims of this study are to determine whether active robotic THA improves clinical outcomes and results in fewer revisions over a long-term follow-up.

METHODS

Patients from 2 US Food and Drug Administration clinical trials (1994-1998 and 2001-2006) who had undergone THA using either an active robotic system or a traditional manual technique were examined to determine if any differences existed in radiographic analysis and patient pain and function using the University of California, Los Angeles; visual analog scale; Health Status Questionnaire (HSQ) pain; HSQ role physical; HSQ physical functioning; Harris pain scores; and the total Western Ontario and McMaster Universities Osteoarthritis Index scores at a mean follow-up of 14 years.

RESULTS

The ROBODOC group had statistically significant higher HSQ pain and Harris pain scores and lower Western Ontario and McMaster Universities Osteoarthritis Index scores. There was no statistically significant difference in probability of a revision for wear between the groups (χ² = 1.80; P = .179), and no revisions for loosening in either group.

CONCLUSION

Prior studies have demonstrated improved implant fit and alignment with the use of this active robot system. This long-term study now shows no failures for stem loosening at a mean follow-up of 14 years and small but potentially important improvements in clinical outcomes in the robot group.

THINK surgical TSolution-One® (Robodoc) total knee arthroplasty

THINK Surgical TSolution-One^® is an active-autonomous, image-based, robotic milling system which enables the surgeon to attain a consistently accurate implant component positioning. The TSolution-One^® system is capable of achieving this through an image-based preoperative planning system which allows the surgeon to create, view and analyse the surgical outcome in 3D. The accuracy and precision of component positioning have been attributed to the following factors: customized distal femoral resection, accurate determination of the femoral rotational alignment, minimization of errors and maintenance of bone temperature with robotic milling. Despite all these advantages, there is still a paucity of long-term, high-quality data that demonstrates the efficacy of robotic-assisted total knee arthroplasty (TKA). Questions regarding radiation risks, prolonged surgical duration and cost-effectiveness remain unanswered. This paper aims to describe: (1) TSolution-One^® surgical technique; (2) limitations and complications; (3) clinical and radiological outcomes.

Technology in Arthroplasty: Are We Improving Value?

PURPOSE OF REVIEW

Total joint arthroplasty is regarded as a highly successful procedure. Patient outcomes and implant longevity, however, are related to proper alignment and position of the prostehses. In an attempt to reduce outliers and improve accuracy and precision of component position, navigation and robotics have been introduced. These technologies, however, come at a price. The goals of this review are to evaluate these technologies in total joint arthroplasty and determine if they add value.

RECENT FINDINGS

Recent studies have demonstrated that navigation and robotics in total joint arthroplasty can decrease outliers while improving accuracy in component positioning. While some studies have demonstrated improved patient reported outcomes, not all studies have shown this to be true. Most studies cite increased cost of equipment and longer operating room times as the major downsides of the technologies at present. Long-term studies are just becoming available and are promising, as some studies have shown decreased revision rates when navigation is used. Finally, there are relatively few studies evaluating the direct cost and value of these technologies. Navigation and robotics have been shown to improve component position in total joint arthroplasty, which can improve patient outcomes and implant longevity. These technologies offer a promising future for total joint arthroplasty.

Robotic-assisted total knee arthroplasty may lead to improvement in quality-of-life measures: a 2-year follow-up of a prospective randomized trial

PURPOSE

Despite reduction in radiological outliers in previous randomized trials comparing robotic-assisted versus conventional total knee arthroplasty (TKA), no differences in short-term functional outcomes were observed. The aim of this study was to determine whether there was improvement in functional outcomes and quality-of-life (QoL) measures between robotic-assisted and conventional TKA.

METHODS

All 60 knees (31 robotic-assisted; 29 conventional) from a previous randomized trial were available for analysis. Differences in range of motion, Knee Society (KSS) knee and function scores, Oxford Knee scores (OKS), SF-36 subscale and summative (physical PCS/mental component scores MCS) were analysed. In addition, patient satisfaction, fulfilment of expectations and the proportion attaining a minimum clinically important difference (MCID) in KSS, OKS and SF-36 were studied.

RESULTS

Both robotic-assisted and conventional TKA displayed significant improvements in majority of the functional outcome scores at 2 years. Despite having a higher rate of complications, the robotic-assisted group displayed a trend towards higher scores in SF-36 QoL measures, with significant differences in SF-36 vitality (p = 0.03), role emotional (p = 0.02) and a larger proportion of patients achieving SF-36 vitality MCID (48.4 vs 13.8 %, p = 0.009). No significant differences in KSS, OKS or satisfaction/expectation rates were noted.

CONCLUSION

Subtle improvements in patient QoL measures were observed in robotic-assisted TKA when compared to conventional TKA. This finding suggests that QoL measures may be more sensitive and clinically important than surgeon-driven objective scores in detecting subtle functional improvements in robotic-assisted TKA patients.

LEVEL OF EVIDENCE

II.

Evidence for robots

Robots have been successfully used in commercial industry and have enabled humans to perform tasks which are repetitive, dangerous and requiring extreme force. Their role has evolved and now includes many aspects of surgery to improve safety and precision. Orthopaedic surgery is largely performed on bones which are rigid immobile structures which can easily be performed by robots with great precision. Robots have been designed for use in orthopaedic surgery including joint arthroplasty and spine surgery. Experimental studies have been published evaluating the role of robots in arthroscopy and trauma surgery. In this article, we will review the incorporation of robots in orthopaedic surgery looking into the evidence in their use.

Robotics in Arthroplasty: A Comprehensive Review

Robotic-assisted orthopedic surgery has been available clinically in some form for over 2 decades, claiming to improve total joint arthroplasty by enhancing the surgeon's ability to reproduce alignment and therefore better restore normal kinematics. Various current systems include a robotic arm, robotic-guided cutting jigs, and robotic milling systems with a diversity of different navigation strategies using active, semiactive, or passive control systems. Semiactive systems have become dominant, providing a haptic window through which the surgeon is able to consistently prepare an arthroplasty based on preoperative planning. A review of previous designs and clinical studies demonstrate that these robotic systems decrease variability and increase precision, primarily focusing on component positioning and alignment. Some early clinical results indicate decreased revision rates and improved patient satisfaction with robotic-assisted arthroplasty. The future design objectives include precise planning and even further improved consistent intraoperative execution. Despite this cautious optimism, many still wonder whether robotics will ultimately increase cost and operative time without objectively improving outcomes. Over the long term, every industry that has seen robotic technology be introduced, ultimately has shown an increase in production capacity, improved accuracy and precision, and lower cost. A new generation of robotic systems is now being introduced into the arthroplasty arena, and early results with unicompartmental knee arthroplasty and total hip arthroplasty have demonstrated improved accuracy of placement, improved satisfaction, and reduced complications. Further studies are needed to confirm the cost effectiveness of these technologies.

Robotic Total Knee Arthroplasty: Surgical Assistant for a Customized Normal Kinematic Knee

Although current total knee arthroplasty (TKA) is considered a highly successful surgical procedure, patients undergoing TKA can still experience substantial functional impairment and increased revision rates as compared with those undergoing total hip arthroplasty. Robotic-assisted surgery has been available clinically for almost 15 years and was developed, in part, to address these concerns. Robotic-assisted surgery aims to improve TKA by enhancing the surgeon's ability to optimize soft tissue balancing, reproduce alignment, and restore normal knee kinematics. Current systems include a robotic arm with a variety of different navigation systems with active, semi-active, or passive control. Semi-active systems have become the dominant strategy, providing a haptic window through which the surgeon consistently prepares a TKA based on preoperative planning. A review of previous designs and clinical studies demonstrates that these robotic systems decrease variability and increase precision, primarily with the mechanical axis and restoration of the joint line. Future design objectives include precise planning and consistent intraoperative execution. Preoperative planning, intraoperative sensors, augmenting surgical instrumentation, and biomimetic surfaces will be used to re-create the 4-bar linkage system in the knee. Implants will be placed so that the knee functions with a medial pivot, lateral rollback, screw home mechanism, and patellar femoral tracking. Soft tissue balancing will become more than equalizing the flexion and extension gaps and will match the kinematics to a normal knee. Together, coupled with advanced knee designs, they may be the key to a patient stating, "My knee feels like my natural knee." [Orthopedics. 2016; 39(5):e822-e827.].

Early experiences with robot-assisted total knee arthroplasty using the DigiMatch™ ROBODOC® surgical system

INTRODUCTION

The use of robotics in total knee arthroplasty (TKA) has been shown to minimise human error, as well as improve the accuracy and precision of component implantation and mechanical axis alignment. The present study aimed to demonstrate that robot-assisted TKA using ROBODOC® is safe and capable of producing a consistent and accurate postoperative mechanical axis.

METHODS

We prospectively recruited 27 consecutive patients who underwent robot-assisted TKA between May and December 2012. Two patients were excluded from the study due to intraoperative technical problems with the robot. Long-leg radiography and computed tomography were performed prior to surgery, and used for mechanical axis measurements and component sizing. DigiMatch™ ROBODOC® Surgical System software version 4.3.6 (Curexo Technology Corp, Fremont, CA, USA) was used in all cases to perform bone cuts in accordance with the preoperative plan.

RESULTS

The postoperative coronal mechanical alignment was within 3 degrees, with a mean alignment of -0.4 ± 1.7 degrees, confirming the accuracy of the preoperative surgical plan and bone cuts. The mean operating time was 96 ± 15 min, and preoperative planning yielded 100% implant sizing accuracy.

CONCLUSION

Robotics has the potential to enable surgeons to consistently attain ideal postoperative alignment. The use of bone movement monitors and an integrated navigation system enhances the safety profile of ROBODOC® by minimising errors. However, the role of the surgeon in TKA is still vital, as the surgeon is ultimately in charge of planning the surgery, its execution and ensuring soft tissue balance during TKA.

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.

Robot-assisted total hip arthroplasty

Precise and accurate biomechanical reconstruction during total hip arthroplasty (THA) is essential for durable long-term survivorship. Accurate fit of cementless hip implants is also crucial to reduce micromotion between the bone-implant interfaces to allow for stable osseointegration. Robotic technology aims to minimize potential human errors and improve implant alignment and fit, and address persisting concerns with modern-day cementless THA. Although robotic THA dates back to the early 1990s, concerns with increased operating times, costs, and complications led to its withdrawal. However, semi-active systems have renewed interest in robot-assisted joint arthroplasty. We reviewed the current technology, its potential benefits, and the reported clinical and radiographic outcomes. Early evidence suggests that robotic use may lead to more accurate reconstruction of radiographic parameters, such as implant positioning, fit, center-of-rotation, and leg-length discrepancy. Further research is needed to determine if these will translate into better outcomes and improved implant longevity to justify increased costs.

Robot-assisted total knee arthroplasty accurately restores the joint line and mechanical axis. A prospective randomised study

Robot-assisted Total Knee Arthroplasty (TKA) improves the accuracy and precision of component implantation and mechanical axis (MA) alignment. Joint-line restoration in robot-assisted TKA is not widely described and joint-line deviation of>5mm results in mid-flexion instability and poor outcomes. We prospectively randomised 60 patients into two groups: 31 patients (robot-assisted), 29 patients (conventional). No MA outliers (>±3° from neutral) or notching was noted in the robot-assisted group as compared with 19.4% (P=0.049) and 10.3% (P=0.238) respectively in the conventional group. The robot-assisted group had 3.23% joint-line outliers (>5mm) as compared to 20.6% in the conventional group (P=0.049). Robot-assisted TKA produces similar short-term clinical outcomes when compared to conventional methods with reduction of MA alignment and joint-line deviation outliers.

Can technology improve alignment during knee arthroplasty

Component malalignment remains a concern in total knee arthroplasty (TKA); therefore, a series of technologies have been developed to improve alignment. The authors conducted a systematic review to compare computer-assisted navigation with conventional instrumentation, and assess the current evidence for patient-matched instrumentation and robot-assisted implantation. An extensive search of the PubMed database for relevant meta-analyses, systematic reviews and original articles was performed, with each study scrutinised by two reviewers. Data on study characteristics and outcomes were extracted from each study and compared. In total 30 studies were included: 10 meta-analyses comparing computer-assisted navigation and conventional instrumentation, 13 studies examining patient-matched instrumentation, and seven investigating robot-assisted implantation. Computer-assisted navigation showed significant and reproducible improvements in mechanical alignment over conventional instrumentation. Patient-matched instrumentation appeared to achieve a high degree of mechanical alignment, although the majority of studies were of poor quality. The data for robot-assisted surgery was less indicative. Computer-assisted navigation improves alignment during TKA over conventional instrumentation. For patient-matched instrumentation and robot-assisted implantation, alignment benefits have not been reliably demonstrated. For all three technologies, clinical benefits cannot currently be assumed, and further studies are required. Although current technologies to improve alignment during TKA appear to result in intra-operative benefits, their clinical impact remains unclear, and surgeons should take this into account when considering their adoption.

A perspective on robotic assistance for knee arthroplasty

Knee arthroplasty is used to treat patients with degenerative joint disease of the knee to reduce pain and restore the function of the joint. Although patient outcomes are generally quite good, there are still a number of patients that are dissatisfied with their procedures. Aside from implant design which has largely become standard, surgical technique is one of the main factors that determine clinical results. Therefore, a lot of effort has gone into improving surgical technique including the use of computer-aided surgery. The latest generation of orthopedic surgical tools involves the use of robotics to enhance the surgeons' abilities to install implants more precisely and consistently. This review presents an evolution of robot-assisted surgical systems for knee replacement with an emphasis on the clinical results available in the literature. Ever since various robotic-assistance systems were developed and used clinically worldwide, studies have demonstrated that these systems are as safe as and more accurate than conventional methods of manual implantation. Robotic surgical assistance will likely result in improved surgical technique and improved clinical results.

Computer-assisted orthopaedic surgery and robotic surgery in total hip arthroplasty

Various systems of computer-assisted orthopaedic surgery (CAOS) in total hip arthroplasty (THA) were reviewed. The first clinically applied system was an active robotic system (ROBODOC), which performed femoral implant cavity preparation as programmed preoperatively. Several reports on cementless THA with ROBODOC showed better stem alignment and less variance in limb-length inequality on radiographic evaluation, less incidence of pulmonary embolic events on transesophageal cardioechogram, and less stress shielding on the dual energy X-ray absorptiometry analysis than conventional manual methods. On the other hand, some studies raise issues with active systems, including a steep learning curve, muscle and nerve damage, and technical complications, such as a procedure stop due to a bone motion during cutting, requiring re-registration and registration failure. Semi-active robotic systems, such as Acrobot and Rio, were developed for ease of surgeon acceptance. The drill bit at the tip of the robotic arm is moved by a surgeon's hand, but it does not move outside of a milling path boundary, which is defined according to three-dimensional (3D) image-based preoperative planning. However, there are still few reports on THA with these semi-active systems. Thanks to the advancements in 3D sensor technology, navigation systems were developed. Navigation is a passive system, which does not perform any actions on patients. It only provides information and guidance to the surgeon who still uses conventional tools to perform the surgery. There are three types of navigation: computed tomography (CT)-based navigation, imageless navigation, and fluoro-navigation. CT-based navigation is the most accurate, but the preoperative planning on CT images takes time that increases cost and radiation exposure. Imageless navigation does not use CT images, but its accuracy depends on the technique of landmark pointing, and it does not take into account the individual uniqueness of the anatomy. Fluoroscopic navigation is good for trauma and spine surgeries, but its benefits are limited in the hip and knee reconstruction surgeries. Several studies have shown that the cup alignment with navigation is more precise than that of the conventional mechanical instruments, and that it is useful for optimizing limb length, range of motion, and stability. Recently, patient specific templates, based on CT images, have attracted attention and some early reports on cup placement, and resurfacing showed improved accuracy of the procedures. These various CAOS systems have pros and cons. Nonetheless, CAOS is a useful tool to help surgeons perform accurately what surgeons want to do in order to better achieve their clinical objectives. Thus, it is important that the surgeon fully understands what he or she should be trying to achieve in THA for each patient.