Robotic-assisted total knee arthroplasty improves accuracy and precision compared to conventional techniques

Conventionally instrumented inverse kinematic alignment for total knee arthroplasty: How is it done?

Purpose

For primary total knee arthroplasty (TKA), there is an increasing trend towards patient-specific alignment strategies such as kinematic alignment (KA) and inverse kinematic alignment (iKA), which by restoring native joint mechanics may yield higher patient satisfaction rates. Second, the most recent Australian joint registry report describes favourable revision rates for conventionally instrumented TKA compared to technology-assisted techniques such as those using navigation, robotics or custom-cutting blocks. The aim of this technique article is to describe in detail a surgical technique for TKA that: (1) utilises the principles of iKA and (2) uses conventionally instrumented guided resections thereby avoiding the use of navigation, robotics or custom blocks.

Methods

A TKA technique is described, whereby inverse kinematic principles are utilised and patient-specific alignment is achieved. Additionally, the patellofemoral compartment of the knee is restored to the native patellofemoral joint line. The sequenced technical note provided may be utilised for cemented or cementless components; cruciate retaining or sacrificing designs and for fixed or rotating platforms.

Results

An uncomplicated, robust and reproducible technique for TKA is described.

Discussion

Knee arthroplasty surgeons may wish to harness the emerging benefits of both a conventionally instrumented technique and a patient-specific alignment strategy.

Level of Evidence

Level V.

Evaluating the accuracy of a new robotically assisted system in cadaveric total knee arthroplasty procedures

BACKGROUND

Robot-assisted total knee arthroplasty (TKA) has been shown to facilitate high-precision bone resection, which is an important goal in TKA. The aim of this cadaveric study was to analyze the accuracy of the target angle and bone resection thickness of a recently introduced robotic TKA system.

METHODS

This study used 4 frozen cadaveric specimens (8 knees), 2 different implant designs, navigation, and a robotic system. The 4 surgeons who participated in this study were trained and familiar with the basic principles and operating procedures of this system. The angle of the bone cuts performed using the robotic system was compared with the target angles from the intraoperative plan. For each bone cut, the resection thickness was recorded and compared with the planned resection thickness.

RESULTS

The mean angular difference for all specimens was less than 1°, and the standard deviation was less than 2°. The mean difference between the planned and measured angles was close to 0 and not significantly different from 0 except for the difference in the frontal tibial component angle, which was 0.88°. The mean difference in the hip-knee-ankle axis angle was - 0.21°± 1.06°. The mean bone resection difference for all specimens was less than 1 mm, and the standard deviation was less than 0.5 mm.

CONCLUSIONS

The results of the cadaveric experimental study showed that the new TKA system can realize highly accurate bone cuts and achieve planned angles and resection thicknesses. Despite the limitations of small sample sizes and large differences between cadaveric and clinical patients, the accuracy of cadaveric experiments provides strong support for subsequent clinical trials.

Is Immediate Postoperative Radiograph Necessary Following Robotic-Assisted Total Knee Arthroplasty?

The necessity of immediate postoperative radiographs following total knee arthroplasty (TKA) has long been debated. With the increasing use of robotic-assisted TKA (RTKA), and thus more precise implant placement, the need for immediate postoperative radiographs to determine implant positioning may be unnecessary. We sought to evaluate implant position on the immediate postoperative radiographs following RTKA to determine their necessity. A retrospective review of 150 RTKAs was performed. The posterior slopes for all TKAs were recorded based on the preoperative three-dimensional template. Additionally, two independent trained researchers (J.G./L.B.) each measured the posterior slope of the postoperative day 0 (POD0) radiograph and postoperative week 2 radiograph. The difference in posterior slope measurement between template and POD0, between template and postoperative week 2, and between POD0 and postoperative week 2 was calculated. Of the 150 TKAs performed, there were no periprosthetic fractures found on the POD0 radiograph. The mean difference between the templated posterior slope and measured posterior slope on POD0 was 0.04 degrees (standard deviation [SD], 1.01; p = 0.615). There was a weak correlation between the two values (rs [95% confidence interval (CI)], 0.38 [0.21, 0.53]). When comparing the template to the postoperative week 2 radiographs, there was a mean difference of 0.02 degrees (SD, 0.48; p = 0.556).  However, a moderate to strong correlation was noted (rs [95% CI], 0.71 [0.61, 0.79]). Comparison of the mean posterior slope from POD0 radiograph to that of postoperative week 2 radiograph showed a mean difference of 0.06 degrees (SD, 1.0; p = 0.427). A weak correlation was found between these two values (rs [95% CI], 0.43 [0.26, 0.56]). Given the accuracy and precision of RTKA, along with the ability to decrease cost and radiation, immediate postoperative radiograph may be unnecessary, when pertaining to the uncomplicated RTKA. However, if there is concern for intraoperative fracture, long stems placed in a revision arthroplasty, or other intraoperative complications, then postoperative radiographs are encouraged.

Cemented vs Cementless Robotic-Assisted Total Knee Arthroplasty Yield Similar Short-Term Clinical Outcomes

Background

In primary total knee arthroplasty (TKA), there is ongoing controversy about optimal fixation (cemented vs cementless). Cemented TKA remains the gold standard, with the largest body of long-term evidence available to support it. However, cementless TKA implants are gaining popularity due to potential biomechanical advantages and a growing body of literature supporting survivorship. Due to paucity of literature investigating fixation methods in robotic-assisted TKA (Ra-TKA), we aim to compare clinical outcomes of cementless Ra-TKA with those of cemented Ra-TKA.

Methods

This is a retrospective cohort study of patients who underwent Ra-TKA by 19 surgeons comparing results of cases using cementless vs cemented fixation. We observed short-term complications, emergency room visits, and readmissions. We collected patient-reported outcomes measurement information system and knee injury and osteoarthritis outcome scores preoperatively and 12 weeks after surgery.

Results

A total of 582 TKA cases were included: 335 cementless and 247 cemented. The patients in the cementless group were younger and had a higher body mass index. The cemented group had a higher rate of return to the operating room, with manipulation under anesthesia for stiffness being the most common indication in both groups. There were no statistically significant differences in 30-day readmissions, 90-day emergency room visits, or patient-reported outcomes.

Conclusions

Our retrospective study demonstrated higher return to operating room in the cemented group vs the cementless group. We reported no differences in any other short-term outcomes between the cementless and cemented Ra-TKA. Our data support efficacy and safety of cementless Ra-TKA at 3-month follow-up.

Small deviations between planned and performed bone cuts using a CT-based robotic-arm-assisted total knee arthroplasty system

PURPOSE

Computed tomography (CT)-based robotic system for total knee arthroplasty (TKA) has shown improved accuracy compared to conventional. This study was designed to (1) confirm the accuracy of the robotic system in achieving the plan and (2) establish the alignment and positioning deviation between final components and planning, by measuring the discrepancy between final implant alignment and the corresponding planned cut.

METHODS

Ninety-six cementless robotic-arm assisted (RA) TKAs were assessed. Bone resections were performed using the haptically controlled robotic arm. Alignment in the coronal and sagittal plane and resection depth of the distal femoral and proximal tibial cuts were recorded with a navigation planar probe. After final components were impacted, the probe was positioned on each implant surface to determine its alignment and positioning.

RESULTS

The mean tibial resections and implanted tibial component's positioning were 0.4 mm (standard deviation, SD: 0.6) and 0.9 mm (SD: 0.8), respectively, higher than planned (p < 0.01). The tibial sagittal cut had 19/96 cases (19.8%) of ±1° outliers from plan. In 40/96 cases (41.7%), the tibial component was more prominent than planned of more than 1 mm. The mean femoral resections and impacted femoral component's positioning was 0.1 mm (SD: 0.8) and 0.2 mm (SD: 0.7), respectively, higher than planned. In 23/96 cases (24.0%), the femoral sagittal cut and femoral component coronal alignment deviated more than ±1° from plan.

CONCLUSIONS

The computed tomography-based robotic-assisted TKA system showed good accuracy regarding bone preparation and component's positioning relative to the planning. Cementless tibial component impaction resulted in the most deviation from plan, with a large proportion of cases resulting in being more prominent than planned.

LEVEL OF EVIDENCE

Level III.

Robotic Total Knee Arthroplasty Surgeon Marketing: Do Claims Align With the Literature?

Background

Robotic total knee arthroplasty (R-TKA) utilization and marketing continue to rise. We examined the marketing on surgeon websites regarding R-TKA benefits and sought to determine if the claims were supported by existing literature.

Methods

A Google search identified 10 physician websites from each of the 5 largest U.S. markets by population with the term "robotic total knee arthroplasty city, state." Claims on websites about R-TKA were categorized. Literature from 2012-2022 was reviewed for data "for" or "against" each claim. Level of evidence for each publication was collected.

Results

Fifty websites were captured that included 59 surgeons. A specific R-TKA platform was mentioned on 68% of websites. Website claims about robotics were placed into 8 major categories. Literature review supported the claims of more precise/accurate, reduced injury to tissue, and less pain with more literature "for" than "against" the claims.

Conclusions

Claims made on physician websites regarding the benefits of R-TKA are variable and not definitively supported by existing literature. Most available data can be categorized into levels of evidence III, IV, and V. There is a paucity of level I evidence to support the various marketing statements. Physicians should be cognizant of both the claims made on their websites and the literature that could be used to support or refute those specific claims.

Short-Term Outcomes of Total Knee Arthroplasty Using a Conventional, Computer-Assisted, and Robotic Technique: A Pilot Clinical Trial

Background: Total Knee Arthroplasty (TKA) is a prevalent surgical procedure for treating severe knee arthritis, aiming to alleviate pain and restore function. Recent advancements have introduced computer-assisted (CAS) and robot-assisted (RA-TKA) surgical techniques as alternatives to conventional methods, promising improved accuracy and patient outcomes. However, comprehensive comparative studies evaluating the short-term outcomes and prostheses survivorship among these techniques are limited. We hypothesized that the outcome of RA-TKA and/or CAS- TKA is advantageous in function and prosthesis survivorship compared to manually implanted prostheses. Methods: This prospective controlled study compared the short-term outcomes and prostheses survivorship following TKA using conventional, CAS, and RA-TKA techniques. One hundred seventy-eight patients requiring TKA were randomly assigned to one of the three surgical groups. The primary outcomes were knee function (KSS knee score) and functional recovery (KSS function score), which were assessed before surgery three years postoperatively. Secondary outcomes included prosthesis alignment, knee range of movements, and complication rates. Survivorship analysis was conducted using Kaplan-Meier curves, with revision surgery as the endpoint. Results: While all three groups showed significant improvements in knee function postoperatively (p < 0.001), the CAS and RA-TKA groups demonstrated superior prosthetic alignment and higher survivorship rates than the conventional group (100%, 97%, and 96%, respectively). However, although the RA-TKA group had a maximal 100% survivorship rate, its knee score was significantly lower than following CAS and conventional techniques (mean 91 ± 3SD vs. mean 93 ± 3SD, p = 0.011). Conclusion: The RA-TKA technique offers advantages over conventional and CAS methods regarding alignment accuracy and short-term survivorship of TKA prostheses. Since short-term prosthesis survivorship indicates the foreseen rates of mid- and long-term survivorship, the current data have a promising indication of the improved TKA prosthesis's long-term survivorship by implementing RA-TKA. According to the presented data, although the survival rates were 100%, 97%, and 96% in the three study groups, no clinical difference in the functional outcome was found despite the better mechanical alignment and higher survivorship in the group of patients treated by the RA-TKA.

Comparison of imageless robotic assisted total knee arthroplasty and conventional total knee arthroplasty: early clinical and radiological outcomes of 200 knees

The aim of this study was to compare the short term clinical and radiological outcomes of imageless robotic and conventional total knee arthroplasty (TKA) and to estimate the accuracy of the two techniques by analysing the outliers after TKA. We have evaluated 200 consecutive knees (158 patients), 100 knees undergoing robotic TKA, and 100 knees treated with conventional TKA. Demographic parameters like age, gender, body mass index, diagnosis and range of motion were obtained. Knee society score (KSS) and Knee society functional score (KSS-F) were used for clinical evaluation. Mechanical alignment (Hip-knee-ankle angle), proximal tibial angle (MPTA), distal femoral angle (LDFA) and tibial slope were analysed for radiological results and outliers were compared between both groups. Outliers were defined when the measured angle exceeded ± 3° from the neutral alignment in each radiological measurement on the final follow-up radiograph.The minimum follow-up was 6 months (range, 6 to 18 months). The preoperative mean HKA angle was 169.7 ± 11.3° in robotic group and 169.3 ± 7.3° in conventional group. There was significant improvement in HKA, LDFA, MPTA and tibial slope compared to the preoperative values in both the groups (p < 0.01). The number of HKA, LDFA and tibial slope outliers were 31, 29 and 37, respectively, in the conventional group compared to 13, 23 and 17 in the robotic group (p < 0.01). There was a significant improvement in the KSS and KSS-F functional scores postoperatively in both the groups (p < 0.01). However, there was no significant difference in the functional scores between the groups postoperatively (p = 0.08). This study showed excellent improvement with both imageless robotic and conventional TKA, with similar clinical outcomes between both groups. However, radiologically robotic TKA showed better accuracy and consistency with fewer outliers compared with conventional TKA.

Associations of postoperative outcomes with geriatric nutritional risk index after conventional and robotic-assisted total knee arthroplasty: a randomized controlled trial

BACKGROUND

The association between postoperative outcomes of robotic-assisted total knee arthroplasty (RA-TKA) and nutrition status among elderly adults remained unclear. The authors aimed to evaluate these associations and provide a nutrition status reference for the surgical technique selection of TKA.

METHODS

In the present study, the authors used data from a multicenter, prospective, randomized controlled project, which recruited patients underwent TKA therapy. A total of 88 elderly adults (age ≥65 years old) were included in this study. Their preoperative and postoperative demographic data and radiographic parameters were collected. Clinical outcomes, including postoperative hip-knee-ankle (HKA) angle deviation, knee society score (KSS), 10 cm visual analog scale, and so on, were observed and compared between the RA-TKA group and the conventional TKA group. Logistic regression was performed to adjust several covariates. In addition, according to the results of restricted cubic splines analyses, all participants were categorized into two groups with GNRI≤100 and GNRI >100 for further subgroup analyses.

RESULTS

Our results showed despite having a lower postoperative HKA angle deviation, the RA-TKA group had a similar postoperative KSS score compared with the conventional TKA group in elderly adults. Among elderly patients with GNRI>100, RA-TKA group achieved significantly more accurate alignment (HKA deviation, P =0.039), but did not obtain more advanced postoperative KSS scores because of the compensatory effect of good nutrition status. However, among elderly patients with GNRI≤100, RA-TKA group had significantly higher postoperative KSS scores compared to the conventional TKA group ( P =0.025) and this association were not altered after adjustment for other covariates.

CONCLUSION

Considering the clinical outcomes of conventional TKA may be more susceptible to the impact of nutrition status, elderly patients with GNRI≤100 seem to be an applicable population for RA-TKA, which is more stable and would gain significantly more clinical benefits compared with conventional TKA.

24-Year-Old Patient with Klippel-Trenaunay Syndrome Underwent Cementless Robotic Cruciate-Retaining TKA: A Case Report

CASE

A 24-year-old man with Klippel-Trenaunay syndrome (KTS) presented with severe knee osteoarthritis unresponsive to conservative measures. Owing to end-stage, debilitating arthritic symptoms, surgery was pursued. Careful preoperative, multidisciplinary planning/treatment included magnetic resonance imaging to characterize the venous malformations throughout the right lower extremity, preoperative sclerotherapy, sirolimus, and robotic-assisted cementless total knee arthroplasty (TKA).

CONCLUSION

Cementless robotic-assisted TKA with selective patellar resurfacing can be a viable option for young KTS patients with severe osteoarthritis when a meticulous multidisciplinary approach, including sclerotherapy and advanced imaging, is undertaken to analyze vascular abnormalities, minimize surgical risks, preserve bone stock, and optimize outcomes.

Disparities in Access to Robotic Knee Arthroplasty: A Geospatial Analysis

BACKGROUND

The utilization of robotic knee arthroplasty (RKA) continues to increase across the United States. The aim of this geospatial analysis was to elucidate if RKA is distributed uniformly across the United States or if disparities exist in patient access.

METHODS

Publicly available provider-finding functions for 5 major manufacturers of RKA systems were used to obtain the practice locations of surgeons performing RKA along with their associated RKA system manufacturer. The average travel distance for each county to the nearest RKA surgeon was calculated and Moran's index clustering analysis was used to find hotspots and coldspots of RKA access. A logistic regression model was used to identify the predictive odds ratios between robotic hotspots and coldspots with county-level sociodemographic variables. Of the 34,216 currently practicing orthopedic surgeons in 2022, 2,571 have access to robotic assistance for knee arthroplasty.

RESULTS

Hotspots of increased travel time were predominantly in West South Central and West North Central census regions. Hotspots were significantly more rural and consisted of predominantly White populations, with lower median income and health insurance coverage.

CONCLUSIONS

The results of the current study align with existing literature, demonstrating absolute geographic access disparities for rural and economically disadvantaged populations. Additionally, relative access disparities persist for minority populations and individuals with high comorbidity burdens residing in urban areas.

Is Tibial Bone Mineral Density Related to Sex, Age, Preoperative Alignment, or Fixation Method in Primary Total Knee Arthroplasty?

BACKGROUND

Cementless total knee arthroplasty (TKA) has regained interest for its potential for long-term biologic fixation. The density of the bone is related to its ability to resist static and cyclic loading and can affect long-term implant fixation; however, little is known about the density distribution of periarticular bone in TKA patients. Thus, we sought to characterize the bone mineral density (BMD) of the proximal tibia in TKA patients.

METHODS

We included 42 women and 50 men (mean age 63 years, range: 50 to 87; mean body mass index 31.6, range: 20.5 to 49.1) who underwent robotic-assisted TKA and had preoperative computed tomography scans with a BMD calibration phantom. Using the robotic surgical plan, we computed the BMD distribution at 1 mm-spaced cross-sections parallel to the tibial cut from 2 mm above the cut to 10 mm below. The BMD was analyzed with respect to patient sex, age, preoperative alignment, and type of fixation.

RESULTS

The BMD decreased from proximal to distal. The greatest changes occurred within ± 2 mm of the tibial cut. Age did not affect BMD for men; however, women between 60 and 70 years had higher BMD than women ≥ 70 years for the total cut (P = .03) and the medial half of the cut (P = .03). Cemented implants were used in 1 86-year-old man and 18 women (seven < 60 years, seven 60 to 70 years, and four ≥ 70 year old). We found only BMD differences between cemented or cementless fixation for women < 60 years.

CONCLUSIONS

To our knowledge, this is the first study to characterize the preoperative BMD distribution in TKA patients relative to the intraoperative tibial cut. Our results indicate that while sex and age may be useful surrogates of BMD, the clinically relevant thresholds for cementless knees remain unclear, offering an area for future studies.

High three-dimensional accuracy of component placement and lower limb alignment using a robotic arm-assisted system and gap-balancing instrument in total knee arthroplasty

PURPOSE

It was hypothesized that robotic arm-assisted total knee arthroplasty (RA-TKA) using additionally a gap-balancing instrumentation will show high accuracy in executing the planning in femoral and tibial component placement throughout the range of knee motion (ROM) during TKA surgery.

METHODS

Prospectively collected data were analysed for patients undergoing RA-TKA. A cruciate retaining cemented design was implanted using the MAKO® robotic system. Lower limb alignment at 0°, 30°, 45°, 60° and 90° of flexion was recorded at the beginning of surgery and finally after implantation of the components. A ligament tensioner was inserted after tibial precut to measure the extension and flexion gap, and final component placement was planned based on 3D CT images. Femoral and tibial component placement was measured in all three planes.

RESULTS

A total of 104 patients were included (mean age 69.4 ± 9 years; 44 male, 60 female). The difference in component placement after planning and final implantation showed less valgus of 0.7° ± 1.4° (p < 0.001), less external rotation of 0.6° ± 1.9° (p = 0.001) and less flexion of 0.9° ± 1.8° (p < 0.001) for the femoral component. The tibial component was placed in more varus of 0.2° ± 0.9° (p = 0.056) and more posterior slope of 0.5° ± 0.9° (p < 0.001). The lower limb alignment in extension was 4.4° ± 5.2° of varus of the native knee and changed to 1.2° ± 1.9° of varus after TKA (p < 0.01).

CONCLUSION

Robotic-assisted TKA helps to achieve the target of alignment and component placement very close to the planning. It allows optimal component placement of off-the-shelf implants respecting patient's specific anatomy.

LEVEL OF EVIDENCE

Level II.

Two- and three-dimensional evaluations following handheld robot-assisted total knee arthroplasty

Robot-assisted total knee arthroplasty (TKA) has proven to be successful in improving the accuracy of component positioning and reducing radiographic outliers. This study aimed to evaluate and compare the alignment of the components using two- and three-dimensional (2D and 3D) measurements following handheld imageless robot-assisted TKA. Seventy consecutive patients underwent primary TKA at our institution using a handheld robot-assisted system. Full-length standing anteroposterior and lateral radiographs were obtained 2 weeks after surgery for assessment of 2D component alignments. Pre- and postoperative computed tomography (CT) images were obtained to assess 3D component alignment. The reference points defined on preoperative CT images were transferred to the postoperative CT images. The absolute errors in the 2D and 3D component alignments from the planned, validated cutting, and validated implantation angles were calculated. Outliers of >  ± 3° of femoral and tibial component alignments in the coronal and sagittal planes were also investigated. All absolute errors in the 2D and 3D component alignments were < 1°, except for the planned and validated cutting angles of the femoral sagittal alignment. No outliers were observed in the femoral or tibial component in the coronal plane. Significant differences between the 2D and 3D measurements were observed for the mean absolute value from the planned and validated cutting angles in the femoral sagittal plane and from the validated implantation angle in the tibial coronal plane. The handheld robot-assisted system demonstrated a high accuracy for component alignment using 2D and 3D evaluations.

Pitfalls with the MAKO Robotic-Arm-Assisted Total Knee Arthroplasty

Robotic-arm-assisted total knee arthroplasty (RATKA) with the MAKO system minimizes deviations in implant alignment and yields superior precision in implant position compared to a manual total knee arthroplasty. In this comprehensive commentary, we present and categorize the limitations and pitfalls of the procedure and we also provide recommendations for avoiding each limitation. The main surgeon-related limitations include prolonged operation duration, loose insertion of the checkpoints and pins, wrong registration and mapping, and damage to soft tissues during bone cutting. The system-related issues include the interruptions of the saw-cutting due to vibrations, specifications for the operating room floor and power supply, the high cost of the system, as well as the cost of each operation due to the extra implants, inability to use the system with various prostheses, wireless connection interruptions between the system's components, and hardware issues with the six joints of the robotic device. In order to circumvent the potential challenges in this surgical procedure, it is essential to possess sufficient experience and undergo comprehensive training. Maintaining continuous awareness of the additional implants throughout the entire operation and prioritizing the preservation of soft tissues are of paramount significance. A profound comprehension of the system and its inherent constraints can also prove to be pivotal in certain situations.

Joint Replacement Technology in the Ambulatory Surgery Center: Current and Future Applications

Total joint replacement (TJR) surgery in the ambulatory surgery centers (ASCs) has grown significantly over the past several years, along with the ability to improve the value of care. Standardization of high-quality, perioperative care is pivotal to the success of a TJR ASC program. As surgeons are experiencing increasing overhead with decreasing reimbursement, technology integration can provide major advantages. In this article, we will therefore highlight several examples of technologies that are changing the field and improving care in the preoperative, intraoperative, and postoperative settings.

Robotic-assisted total knee arthroplasty results in decreased incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty

OBJECTIVE

Periprosthetic fracture (PPF) is an uncommon but devastating complication after total knee arthroplasty (TKA). Anterior femoral notching (AFN) is one of a perioperative risk factor for PPF. The main purpose of this study was to compare between the rates of anterior femoral notching (AFN) and supracondylar periprosthetic femoral fracture (sPPF) of manual TKA and robotic arm-assisted TKA (RATKA). Meanwhile, blood loss, transfusion rates, inflammatory responses, complications, early clinical and radiological outcomes were also assessed.

METHODS

This retrospective study included 330 patients (133 RATKA and 197 manual TKA). Differences in risks of inflammatory, blood loss, complications (periprosthetic fracture and periprosthetic joint infection), pre-operative and post-operative distal lateral femoral angle (LDFA), distal femoral width (DFW), prosthesis-distal femoral width (PDFW) ratio, AFN, femoral component flexion angle (FCFA), peri-operative and post-operative functional outcomes between the RATKA and manual TKA groups were compared.

RESULTS

The operation time and postoperative CRP level in the RATKA group was significantly longer and higher than that in the manual TKA group (p < .001). However, there was no significant difference in postoperative WBC level (p = .217), hemoglobin loss (p = .362), postoperative drainage (p = .836), and periprosthetic fracture (p = 1.000). There was no significant difference in LDFA (p > .05), DFW(p = .834), PDFW ratio (p = .089) and FCFA (p = .315) between the two groups, but the rate of AFN in the RATKA group was significantly lower than that in the manual TKA group (p < .05). There was no significant difference in ROM between the two groups on POD3, POD 90 and 1 year (p < .05), but the FJS-12 score in the RATKA group was higher than that in the manual TKA group on 1 year (p = .001).

CONCLUSION

Robotic-assisted total knee arthroplasty can decrease the incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty.

Influence of posterior tibial slope on postoperative outcomes after postero-stabilized and condylar-stabilized total knee arthroplasty

PURPOSE

To compare clinical outcomes and surgical times of two different types of total knee arthroplasty(TKA), postero-stabilized(PS) and condylar-stabilized(CS), in relation to posterior tibial slope(PTS) values and the deviation of these values from the surgical technique.

METHODS

168 patients undergoing TKA surgery between 2016 and 2020 met our inclusion criteria. For each case, gender, age at surgery, operating time, type of implant and preoperative PTS(preop-PTS) and postoperative PTS(postop-PTS) measurements were collected; difference(∆PTS) between preop-PTS and postop-PTS was also calculated. Short Form 12 Mental and Physical scores(SF-12 M and P) and functional Knee Society Score(fKSS) were collected preoperatively and at a minimum of 12 months postoperatively. Four subgroups were thus created in relation to PS or CS system and postop-PTS value(≤ 5°and > 5°).

RESULTS

Of the 168 patients, 96 had a PS system and 72 CS system. Performing a CS-TKA took less time than a PS-TKA(p < 0.05). SF-12P showed better results(p < 0.05) in CS-TKA group than PS-TKA, probably because of the younger age of CS-TKA patients(p < 0.05). In the PS > 5° all examined postoperative scores were better(p < 0.05) than PS ≤ 5°, while only fKSS was better(p < 0.05) in CS > 5° than CS ≤ 5°. No significant difference(p > 0.05) in terms of postoperative outcomes between the PS > 5° and CS > 5° was noted, whereas only SF-12P was better in the CS ≤ 5° compared with PS ≤ 5°. Highest values of SF-12 M and fKSS were obtained in the PS ≤ 5°, in which postop-PTS was closer to technique.

CONCLUSION

When performing a PS-TKA, the best result was obtained with a postop-PTS > 5°, but comparable outcomes between the two systems were evident with postop-PTS > 5°. It is crucial to come as close as possible to the indications reported in surgical technique regardless ∆PTS.

Robotic-arm assisted total knee arthroplasty is associated with comparable functional outcomes but improved forgotten joint scores compared with conventional manual total knee arthroplasty at five-year follow-up

PURPOSE

This study reports the five-year functional outcomes from a prospective cohort study comparing robotic-arm assisted total knee arthroplasty (RO TKA) versus conventional manual total knee arthroplasty (CO TKA).

METHODS

This prospective single-surgeon study included 120 patients with symptomatic end-stage knee arthritis undergoing primary TKA. This included 60 consecutive patients undergoing CO TKA followed by 60 consecutive patients undergoing RO TKA using a semi-automated robotic device. Study patients were reviewed at one, two, and five years after surgery and the following outcomes recorded: The University of California at Los Angeles activity-level (UCLA), Knee Society Score (KSS), Oxford Knee Score (OKS) Forgotten Joint Score (FJS), and any complications.

RESULTS

There were no statistical differences between RO TKA and CO TKA in the median UCLA score (p = N.S), median KSS (p = N.S), and median OKS (p = N.S) at five-year follow-up. RO-TKA was associated with statistically significant improvements in the FJS at one (p = 0.001), two (p = 0.003), and five (p = 0.025) years of follow-up compared with CO TKA. There was no statistical difference in the incidence of knee stiffness requiring manipulation under anesthesia between the two treatment groups (p = N.S).

CONCLUSION

Patients in both treatment groups had excellent functional outcomes with comparable patient reported outcomes at five-year follow-up. RO TKA was associated with statistically significant improvements in the FJS compared with CO TKA, but these differences did not reach the minimal clinically important difference at any follow-up interval. There was no overall difference in complications between the two treatment groups at five-year follow-up.

LEVEL OF EVIDENCE

II (Prospective cohort study).

Better forgotten joint scores when the angle of the prosthetic trochlea is lateral to the quadriceps vector in kinematically aligned total knee arthroplasty

PURPOSE

The primary aim was to analyze unrestricted kinematic alignment (unKA) total knee arthroplasty (TKA) and determine the frequency of medial deviation of the prosthetic trochlear angle (PTA) of the femoral component relative to the quadriceps vector (QV) that terminates at the anterior inferior iliac spine (AIIS), and whether patients with medial deviation had a worse Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) relative to those with lateral deviation. The secondary aim was to determine the frequency of medial deviation for mechanical alignment (MA) TKA simulations.

METHODS

From a database of a single surgeon, the study extracted de-identified data on 147 patients with a CT scanogram showing the pelvis and AIIS, a limb with an unKA TKA, and a native (i.e., healthy) opposite limb. On the scanogram, an examiner, blinded to the PROMs, measured the PTA-QV angle on the unKA TKA and on the opposite limb simulated MA TKA by drawing the PTA at 6° valgus relative to the femoral mechanical axis and measuring the PTA-QV angle.

RESULTS

Medial deviation of the PTA occurred in 86% of patients with unKA TKA, and the 126 with medial deviation had a 17/1 point worse median FJS/OKS than the 21 with lateral deviation at a mean follow-up of 47 ± 8 months, respectively (p < 0.0001, p = 0.0053). In addition, 21%, 17%, and 8% of MA TKA had medial deviation after radiographic simulation using reported surgical errors for manual, patient-specific, and robotic instrumentation, respectively.

CONCLUSION

In most patients with unKA TKA and a smaller proportion with MA TKA, a PTA of 6° valgus was medial to the QV, which, by excluding the patient's Q-angle, might alter patellofemoral kinematics like an incorrectly oriented trochleoplasty. The 17-point worse FJS in the patients with an unKA TKA and medial deviation of the PTA suggests the surgical target should be to orient the PTA lateral to the QV.

LEVEL OF EVIDENCE

IV.

Adoption of robotics in arthroplasty- a survey of perceptions, utilization and challenges with technology amongst Indian surgeons

Introduction

Total joint replacement surgeries are standard procedures for managing end-stage hip or knee arthritis. Despite advances in technology, some patients experience dissatisfaction after total knee arthroplasty (TKA). Robotic technology has evolved significantly and has shown promise in improving component positioning, alignment, and surgical outcomes. However, the widespread adoption of robotics in arthroplasty faces challenges such as high costs, a steep learning curve, and limited evidence on long-term outcomes.

Methods

This cross-sectional observational study used a structured self-administered online survey to assess the perceptions of Indian arthroplasty surgeons regarding robotic technology. The survey included questions about the surgeon's background, experience, perceptions of robotic joint replacement, and limiting factors for robotic usage. A total of 417 responses were collected from practising arthroplasty surgeons.

Results

Most participants(78.1 %) expressed a willingness to adopt robotics in their arthroplasty practice if the cost of installation was reduced. Robotic users were more convinced about the benefits of robotics, including improved alignment, reduced pain, faster rehabilitation, and better outcomes. High-volume robotic surgeons demonstrated a greater belief in the broader potential of robotics beyond implant positioning and alignment. The major barriers to adoption were the high cost of installation and limited insurance coverage for robotic-assisted procedures. Lack of formal robotic training opportunities, resistance from corporate management, patient acceptance issues, and limited published literature supporting robotic advantages were also cited as limiting factors.

Conclusion

Robotic technology is increasingly being adopted in India for TKA. The main obstacle to widespread adoption is the high cost of installation. As technology costs decrease, we can expect a rise in the number of installations across the country. Advocacy from national orthopaedic organizations may be needed to address insurance reimbursement challenges. Overall, this study provides valuable insights into the perceptions and challenges associated with the adoption of robotic technology in arthroplasty in India.

Fostering Excellence in Knee Arthroplasty: Developing Optimal Patient Care Pathways and Inspiring Knowledge Transfer of Advanced Surgical Techniques

Osteoarthritis of the knee is common. Early sports trauma or cartilage defects are risk factors for osteoarthritis. If conservative treatment fails, partial or total joint replacement is often performed. A joint replacement aims to restore physiological biomechanics and the quality of life of affected patients. Total knee arthroplasty is one of the most performed surgeries in musculoskeletal medicine. Several developments have taken place over the last decades that have truly altered the way we look at knee arthroplasty today. Some of the fascinating aspects will be presented and discussed in the present narrative review.

Robotic-Assisted Total Knee Arthroplasty Can Increase Frequency of Achieving Target Limb Alignment in Primary Total Knee Arthroplasty for Preoperative Valgus Deformity

Background

Robotic-assisted total knee arthroplasty (rTKA) has been shown to reduce the number of alignment outliers and to improve component positioning compared to manual TKA (mTKA). The primary purpose of this investigation was to compare the frequency of achieving target postoperative limb alignment and component positioning for rTKA vs mTKA.

Methods

A retrospective comparative study was performed on 250 patients undergoing primary TKA by 2 fellowship-trained arthroplasty surgeons. Surgeon A performed predominantly rTKA (103 cases) with the ROSA system (Zimmer Biomet, Warsaw, IN) and less frequently mTKA (44 cases) with conventional instrumentation. Surgeon B performed only mTKA (103 cases). Target limb alignment for surgeon A was 0° for all cases and for surgeon B was 2° varus for varus knees and 0° for valgus knees. Radiographic measurements were determined by 2 reviewers. Target zone was set at ± 2 degrees from the predefined target.

Results

When comparing rTKA to mTKA performed by different surgeons, there were no differences in the percentage within the target zone (57.28% vs 53.40%, P = .575), but rTKA did result in a greater percentage for cases with preoperative valgus (71.42% vs 44.12%, P = .031). Patient-reported Outcomes Measurement Information System Global-10 physical scores were statistically higher at both 3 (P = .016) and 6 months (P = .001) postoperatively for rTKA compared to mTKA performed by different surgeons.

Conclusions

Although experienced surgeons can achieve target limb alignment correction with similar frequency when comparing rTKA to mTKA for all cases, rTKA may achieve target limb alignment with more accuracy for preoperative valgus deformity.

Level of Evidence

Retrospective Cohort Study, Level III.

Conversion of Patellofemoral Arthroplasty to Robotic-Assisted Total Knee Arthroplasty

Conversion of patellofemoral arthroplasty to total knee arthroplasty (TKA) has been described as similar to primary TKA, although it may come with more challenges and worse outcomes. With the increased rate of revision following conversion TKA vs primary TKA, robotically assisted TKA provides an alternative technique to manual conversion. We present 3 cases of robot-assisted conversion of prior patellofemoral arthroplasty to TKA with good mechanical and clinical outcomes and no intraoperative complications.

Optimizing Asymmetric Native Knee Flexion Gap Balance Promotes Superior Outcomes in Primary Total Knee Arthroplasty

INTRODUCTION

Replicating native knee kinematics remains the ultimate goal of total knee arthroplasty (TKA). Technology, such as robotics, provides robust intraoperative data; however, no evidence-based targets currently exist for improved clinical outcomes. Furthermore, some surgeons target a rectangular flexion space in TKA unlike the native knee. This study evaluated the effect of in vivo flexion gap asymmetry on patient-reported outcome measures (PROMs) in contemporary TKA.

METHODS

In vivo tibiofemoral joint space dimensions were measured during 129 TKAs using a calibrated tension device before and after complete posterior cruciate ligament resection. PROMs were compared based on the final dimensions and the change in flexion gap dimensions at 90° of flexion: (1) equal laxity, (2) lateral laxity, and (3) medial laxity. Groups did not differ by demographics ( P ≥ 0.347), clinical follow-up ( P = 0.134), tibiofemoral alignment ( P = 0.498), or preoperative PROMs ( P ≥ 0.093). Mean follow-up for the cohort was 1.5 years (range, 1-3).

RESULTS

Pain with climbing stairs, pain while standing upright, and knees "always feeling normal" scores were superior for patients with equal or lateral laxity compared with medial laxity ( P ≤ 0.064). Pain with level walking, University of California Los Angeles activity level, KOOS JR, and satisfaction scores also tended to be superior for patients with equal or lateral laxity, although it lacked statistical significance ( P ≥ 0.111).

DISCUSSION

Results of this study suggest that patients with either an equally tensioned rectangular flexion space or with later-flexion lateral laxity after posterior cruciate ligament resection may achieve superior PROMs. Findings support the clinical benefit of facilitating posterolateral femoral roll back in flexion, which mimics native knee kinematics and further helps define targets for advanced technology.

Operating room efficiency after the implementation of MAKO robotic-assisted total knee arthroplasty

INTRODUCTION

The aim of this study was to examine if robotic-assisted total knee arthroplasty (RATKA) is cost- and time-effective in terms of implant stock and perioperative parameters, as optimizing perioperative efficiency may contribute to value-based care.

MATERIALS AND METHODS

Four hundred thirty-two consecutive patients who received primary total knee arthroplasties (TKAs) from May 2017 to March 2020 in a regional hospital were included in this study. Operating room time (OR time), surgical time, number of trays, insert thickness, and length of stay (LOS) were assessed and compared for a cohort group with navigation-assisted procedures to a group with robotic-assisted procedures (MAKO, Stryker, USA). Prediction of implant size was assessed for the robotic-assisted group. The Mann-Whitney U test was used for comparisons between groups when the normality assumption was not met. Categorical variables were assessed using the Fisher's exact test. p < 0.05 was considered statistically significant.

RESULTS

In the RATKA group, we noticed a significant mean reduction of 11 min in total OR time (p < 0.001), the use of thinner insert (p < 0.001), and a shorter mean length of stay of 1 day (p < 0.001). Compared to the navigation group, surgical time was not significantly longer, nor clinically relevant (0.238). In 76.9% of the robotic-assisted cases, the estimated implant size was equal to the final size and in all other cases, the preoperative implant size was oversized.

CONCLUSION

The introduction of the MAKO robotic-assisted total knee arthroplasty resulted in a gain in operating room time, a thinner and more predictable insert thickness, a shorter length of stay in hospital, and less instrumentation compared to navigation-assisted procedures. Level of evidence Level III, Retrospective cohort study.

A Bibliometric Analysis of the Top 100 Most Influential Studies on Robotic Arthroplasty

Background

The use of robotics in arthroplasty surgery has increased substantially in recent years. The purpose of this study was to objectively identify the 100 most influential studies in the robotic arthroplasty literature and to conduct a bibliometric analysis of these studies to describe their key characteristics.

Methods

The Clarivate Analytics Web of Knowledge database was used to gather data and metrics for robotic arthroplasty research using Boolean queries. The search list was sorted in descending order by the number of citations, and articles were included or excluded based on clinical relevance to robotic arthroplasty.

Results

The top 100 studies were cited a total of 5770 times from 1997 to 2021, with rapid growth in both citation generation and the number of articles published occurring in the past 5 years. The top 100 robotic arthroplasty articles originated from 12 countries, with the United States being responsible for almost half of the top 100. The most common study types were comparative studies (36) followed by case series (20), and the most common levels of evidence were III (23) and IV (33).

Conclusions

Research on robotic arthroplasty is rapidly growing and originates from a wide variety of countries, academic institutions, and with significant industry influence. This article serves as a reference to direct orthopaedic practitioners to the 100 most influential studies in robotic arthroplasty. We hope that these 100 studies and the analysis we provide aid healthcare professionals in efficiently assessing consensus, trends, and needs within the field.

Current Concepts in Alignment in Total Knee Arthroplasty

BACKGROUND

In an effort to increase satisfaction among total knee arthroplasty (TKA) patients, emphasis has been placed on implant positioning and limb alignment. Traditionally, the aim for TKA has been to achieve a neutral mechanical alignment (MA) to maximize implant longevity. However, with the recent spike in interest in individualized alignment techniques and with the advent of new technologies, surgeons are slowly evolving away from classical MA.

METHODS

This review elucidates the differences in alignment techniques for TKA, describes the concept of knee phenotypes, summarizes comparative studies between MA and individualized alignment, and provides a simple way to incorporate the latter into surgeons' practice.

RESULTS

In order to manage patients by applying these strategies in day-to-day practice, a basic understanding of the aforementioned concepts is essential. Transition to an individualized alignment technique should be done gradually with caution in a stepwise approach.

CONCLUSION

Alignment and implant positioning are now at the heart of the debate and surgeons are investigating a more personalized approach to TKA.

MAKO robot-assisted total knee arthroplasty cannot reduce the aggravation of ankle varus incongruence after genu varus correction ≥ 10°: a radiographic assessment

INTRODUCTION

The objective of this study was to investigate the ankle alignment alterations after the correction of knee varus deformity in MAKO robot-assisted total knee arthroplasty (MA-TKA).

METHODS

A retrospective analysis was conducted for 108 patients with TKA from February 2021 to February 2022. Patients were divided into two groups based on MAKO robot involvement during the procedure: the MA-TKA group (n = 36) and the conventional manual total knee arthroplasty (CM-TKA) group (n = 72). The patients were divided into four subgroups according to the degree of surgical correction of the knee varus deformity. Seven radiological measurements were evaluated pre and post-surgery: mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), lateral distal tibial angle (LDTA), tibial plafond inclination angle (TPIA), talar inclination angle (TIA), and tibiotalar tilt angle (TTTA). TTTA is a quantitative representation of the extent of ankle incongruence.

RESULTS

The number of mTFA, mLDFA, and MPTA outliers in the MA-TKA group was significantly lower compared to the CM-TKA group (P<0.05). Knee varus deformity was properly corrected and the mechanical axis was restored in all patients, regardless of the treatment group. Only for varus corrections ≥ 10° did TTTA change significantly (p < 0.01) and ankle varus incongruence aggravate post-operation. The ΔTTTA correlated negatively with ΔTFA (r=-0.310,P = 0.001) and correlated positively with ΔTPIA (r = 0.490,P = 0.000). When the varus correction was ≥ 7.55°, the probability of ankle varus incongruence exacerbation increased 4.86-fold.

CONCLUSION

Compared with CM-TKA, MA-TKA osteotomy showed more precision but was unable to reduce post-operation ankle varus incongruence. When the varus correction ≥ 10°, ankle varus incongruence aggravated, while when the varus correction ≥ 7.55°, the probability of ankle varus incongruence increased 4.86-fold. This may occasion the pathogenesis of ankle pain following TKA.

Correcting for distal femoral asymmetry is necessary to determine postoperative alignment deviations from planned alignment of the femoral component

BACKGROUND

One method for assessing the accuracy of manual, patient-specific, navigational, and robotic-assisted total knee arthroplasty (TKA) instrumentation is to use a post-operative computer tomogram and determine the deviation of the femoral component alignment relative to the planned alignment in the native (i.e. healthy) contralateral distal femoral epiphysis. However, side-to-side asymmetry might introduce errors which inflate alignment deviations. This study quantified asymmetry in the distal femoral epiphysis.

METHODS

High resolution CT images (0.5 mm slice thickness) were acquired from bilateral lower limb specimens of 13 skeletally mature subjects with no skeletal abnormalities. Images were segmented to generate 3D femur models. Asymmetry was quantified by differences in positions and orientations required to shape-match the distal epiphysis of the mirror 3D femur model to the distal epiphysis of the contralateral 3D femur model.

RESULTS

Asymmetry was due to random rather than systematic differences. Random differences (i.e. standard deviations) in proximal-distal (P-D) and anterior-posterior (A-P) positions were 1.1 mm and in varus-valgus (V-V) and internal-external (I-E) orientations were 0.9° and 1.3°, respectively. These represented substantial relative errors of up to 50 % in previously reported overall alignment deviations.

CONCLUSIONS

Although small in an absolute sense, asymmetry of the distal femur epiphysis introduced substantial relative errors when assessing accuracy of femoral component alignment in TKA. When post-operative computer tomograms are used to assess the accuracy of manual, patient specific, navigational, and robotic-assisted TKA instrumentation, the overall deviation should be corrected for asymmetry to better indicate the accuracy of the surgical technique.

Patellofemoral Arthroplasty Is an Efficient Strategy for Isolated Patellofemoral Osteoarthritis with or without Robotic-Assisted System

There is relative paucity in the literature concerning outcomes after robotic-assisted Patellofemoral Arthroplasty (PFA). The aims were (1) to evaluate outcomes in patients undergoing PFA with inlay or onlay components, with or without robotic arm assistance and (2) to identify risk factors of poor outcomes after PFA. This retrospective study included 77 PFA for isolated patellofemoral joint osteoarthritis, assigned to three groups (18 conventional technique, 17 image-free robotic-assisted system and 42 image-based robotic-assisted system). The demographic data were comparable between the three groups. The clinical outcomes assessed were: Visual Analogue Scale, Knee Society Score, Kujala score and satisfaction rate. The radiological measures were: Caton Deschamps index, patellar tilt and frontal alignment of the trochlea. Functional outcomes, satisfaction rate and residual pain were comparable between the three groups. Patellar tilt improvement was superior when a robotic device was used (either image-based or image-free) compared to the conventional technique. There were three revisions (3.9%) at the last follow-up related to femorotibial osteoarthritis progression. Multivariate analysis found no significant risk factors for poor outcomes, with respect to the surgical technique or implant design. Functional outcomes and revisions rate after PFA were comparable between the surgical techniques and implants. Robotic-assisted systems were associated with a superior improvement of the patellar tilt compared to the conventional technique.

Mechanical alignment tolerance of a cruciate-retaining knee prosthesis under gait loading—A finite element analysis

Component alignment is one of the most crucial factors affecting total knee arthroplasty’s clinical outcome and survival. This study aimed to investigate how coronal, sagittal, and transverse malalignment affects the mechanical behavior of the tibial insert and to determine a suitable alignment tolerance on the coronal, sagittal, and transverse planes. A finite element model of a cruciate-retaining knee prosthesis was assembled with different joint alignments (−10°, −7°, −5°, −3°, 0°, 3°, 5°, 7°, 10°) to assess the effect of malalignment under gait loading. The results showed that varus or valgus, extension, internal rotation, and excessive external rotation malalignments increased the maximum Von Mises stress and contact pressure on the tibial insert. The mechanical alignment tolerance of the studied prosthesis on the coronal, sagittal, and transverse planes was 3° varus to 3° valgus, 0°–10° flexion, and 0°–5° external rotation, respectively. This study suggests that each prosthesis should include a tolerance range for the joint alignment angle on the three planes, which may be used during surgical planning.

Image-Free Robotic-Assisted Total Knee Arthroplasty Results in Quicker Recovery but Equivalent One-Year Outcomes Compared to Conventional Total Knee Arthroplasty

BACKGROUND

Few studies have addressed whether robotic-assisted total knee arthroplasty (RA-TKA) significantly impacts functional outcomes. This study was conducted to determine whether image-free RA-TKA improves function compared to conventional total knee arthroplasty (C-TKA), performed without the utilization of robotics or navigation, using the Minimal Clinically Important Difference (MCID) and Patient Acceptable Symptom State (PASS) as measures of meaningful clinical improvement.

METHODS

A multicenter propensity score-matched retrospective study was conducted of RA-TKA using an image-free robotic system and C-TKA cases at an average follow-up of 14 months (range, 12 months to 20 months). Consecutive patients who underwent primary unilateral TKA and had a preoperative and postoperative Knee Injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR) were included. The primary outcomes were the MCID and PASS for KOOS-JR. 254 RA-TKA and 762 C-TKA patients were included, with no significant differences in sex, age, body mass index, or comorbidities.

RESULTS

Preoperative KOOS-JR scores were similar in the RA-TKA and C-TKA cohorts. Significantly greater improvement in KOOS-JR scores were achieved at 4 to 6 weeks postoperatively with RA-TKA compared to C-TKA. While the mean 1-year postoperative KOOS-JR was significantly higher in the RA-TKA cohort, no significant differences were found in the Delta KOOS-JR scores between the cohorts, when comparing preoperative and 1-year postoperative. No significant differences existed in the rates of MCID or PASS being achieved.

CONCLUSION

Image-free RA-TKA reduces pain and improves early functional recovery compared to C-TKA at 4 to 6 weeks, but functional outcomes at 1 year are equivalent based on the MCID and PASS for KOOS-JR.

Alignment options and robotics in total knee arthroplasty

Total knee arthroplasty is one of the most widely performed surgical procedures today. Its widespread popularity has helped drive innovation and improvement in the field. Different schools of thought have developed regarding the best way to perform this operation. Specifically, there are controversaries regarding the best alignment philosophy for the femoral and tibial components to optimize implant stability and longevity. Traditionally, neutral mechanical alignment has been the preferred alignment target. More recently, some surgeons advocate for alignment matching the patient's pre-arthritic anatomic alignment ("physiologic" varus or valgus), which has been described as kinematic alignment. Functional alignment is a hybrid technique that focuses on the coronal plane minimizing soft tissue releases. To date, there is no evidence demonstrating superiority of one method over another. There is growing popularity of robotic surgical techniques to improve accuracy of implant position and alignment. The choice of alignment philosophy is an important aspect of robotic assisted TKA surgery and has the potential to clarify the optimal alignment technique.

How does the use of quantified gap-balancing affect component positioning and limb alignment in robotic total knee arthroplasty using functional alignment philosophy? A comparison of two robotic platforms

PURPOSE

This study aimed to compare the effect of an image-based (MAKO) system using a gap-balancing technique with an imageless (OMNIbot) robotic tool utilising a femur-first measured resection technique.

METHODS

A retrospective cohort study was performed on patients undergoing primary TKA with a functional alignment philosophy performed by a single surgeon using either the MAKO or OMNIbot robotic systems. In all cases, the surgeon's goal was to create a balanced knee and correct sagittal deformity (eliminate any fixed flexion deformity). Intra-operative data and patient-reported outcomes (PROMS) were compared.

RESULTS

A total of 207 MAKO TKA and 298 OMNIbot TKAs were analysed. MAKO TKA patients were younger (67 vs 69, p=0.002) than OMNIbot patients. There were no other demographic or pre-operative alignment differences. Regarding implant positioning, in MAKO TKAs the femoral component was more externally rotated in relation to the posterior condylar axis (2.3° vs 0.1°, p<0.001), had less valgus femoral cuts (1.6° vs 2.7° valgus, p<0.001) and more varus tibial cuts (2.4° vs 1.9° varus, p<0.001), and had more bone resected compared to OMNIbot TKAs. OMNIbot cases were more likely to require tibial re-cuts than MAKO (15% vs 2%, p<0.001). There were no differences in femur recut rates, soft tissue releases, or rate of achieving target coronal and sagittal leg alignment between robotic systems. A subgroup analysis of 100 MAKO and 100 OMNIbot propensity-matched TKAs with 12-month follow-up showed no significant difference in OKS (42 vs 43, p=0.7) or OKS PASS scores (83% vs 91%, p=0.1). MAKO TKAs reported significantly better symptoms according to their KOOS symptoms score than patients that had OMNIbot TKAs (87 vs 82, p=0.02) with a higher proportion of KOOS PASS rates, at a slightly longer follow-up time (20 months vs 14 months, p<0.001). There were no other differences in PROMS.

CONCLUSION

A gap-balanced technique with an image-based robotic system (MAKO) results in different implant positioning and bone resection and reduces tibial recuts compared to a femur-first measured resection technique with an imageless robotic system (OMNIbot). Both systems achieve equal coronal and sagittal deformity correction and good patient outcomes at short-term follow-ups irrespective of these differences.

Status of robot-assisted artificial total joint arthroplasty in China: a cross-sectional survey of joint surgeons

PURPOSE

The purpose of this study is to report on the use of Robotic-assisted total joint arthroplasty (RA-TJA) in China as well as the experience and expectations of Chinese doctors regarding this technology.

METHOD

A self-administered questionnaire was used to assess the current status of RA-TJA in China, the practical experience and suggestions for improvement of the technology by joint surgeons who have performed RA-TJA, and the interest and expectations of orthopaedic surgeons who have not used RA-TJA. The questionnaire was administered to all the physicians of the Chinese Association of Orthopedic Surgeons (CAOS).

RESULT

A total of 372 qualified questionnaires were generated, among which 28% (n = 104) of the respondents had performed RA-TJA, among those who had performed RA-TJA. When asked how helpful the joint replacement robot was actually/expected to be, there was no significant difference between the expected and actual experience of nonusers and users (p ≥ 0.05); the biggest disadvantage of the current development of RA-TJA was perceived as additional charges to the patient by those who had used it, while those who had not used it perceived it as a limitation of their hospital, both of which were significant differences. Most respondents in both groups (used: 94.2%; not used: 91.4%) were confident in the clinical development of the joint replacement robot.

CONCLUSION

This survey provides cross-sectional data on the current status of Chinese joint surgeons using or not using robots in their daily clinical practice. Improving surgical precision was the consensus of most respondents, while high surgical costs and limitations of hospital conditions were barriers to its development in China.

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.

How long does image based robotic total knee arthroplasty take during the learning phase? Analysis of the key steps from the first fifty cases

INTRODUCTION

Robotically assisted total knee arthroplasty (RA-TKA) is an emerging surgical tool. The purpose of this study was to analyze the length of time taken to perform the key steps of a RA-TKA for a surgeon and centre new to the MAKO robotic system.

METHOD

This was a prospective cohort study of the first 50 patients undergoing TKA using a robotic platform (Mako, Stryker, Kalamazoo, MI, USA) performed by a single surgeon. Each key surgical step was recorded. The first 50 patients were chronologically allocated into five groups of ten and compared.

RESULTS

Mean operation length was 59.4 ± 7.4 min with significant improvement after 30 cases. A significant effect on certain steps of the surgery also occurred over 50 cases: after 30 cases for pre-operative planning (3.8 min in group 1 versus 1.2 min in group 4, p < 0.005), ten cases for registration time (5.2 min in group 1 versus 3.8 in group 2, p = 0.039) and ten cases for tibial cutting time (1.6 min in group 1 versus 1.3 in group 2, p < 0.005). Nurse setup, femur cutting, and intraoperative planning did not demonstrate a significant improvement in time over 50 cases.

CONCLUSION

A significant decrease in total operating length occurred after the 30th case. Anatomical registration and tibial cutting time demonstrated the largest improvements. MAKO image-based robotically assisted TKA is not a time-intensive intervention for both the surgeon and scrub nursing staff, and significant improvements in total surgical time occurs early in the learning phase.

Robotic-assisted revision total knee arthroplasty: a novel surgical technique

BACKGROUND

Revision total knee arthroplasty is a challenging procedure. The robotic-assisted system has been shown to enhance the accuracy of preoperative planning and improve reproducibility in primary arthroplasty surgeries. The aim of this paper was to describe the surgical technique for robotic-assisted revision total knee arthroplasty and the potential benefits of this technique.

METHOD

This single-centre retrospective study included a total of 19 patients recruited from April 1, 2021 to April 30, 2022. Inclusion criteria were patients who had Mako™ robotic-assisted revision total knee arthroplasty done within the study period with a more than 6 months follow-up. Statistical analysis was done using Microsoft Excel 16.0.

RESULTS

All 19 patients were followed up for 6 to 18 months. All patients in this study had uneventful recoveries without needing any re-revision surgery when reviewed to date.

CONCLUSION

With the development of dedicated revision total knee software, robot-assisted revision TKA can be a promising technique that may improve surgical outcomes by increasing the accuracy of implant placement, and soft tissue protection and achieving a better well-balanced knee.

Comparative assessment of current robotic-assisted systems in primary total knee arthroplasty

Robotic-assisted total knee arthroplasty (TKA) has proven higher accuracy, fewer alignment outliers, and improved short-term clinical outcomes when compared to conventional TKA. However, evidence of cost-effectiveness and individual superiority of one system over another is the subject of further research. Despite its growing adoption rate, published results are still limited and comparative studies are scarce. This review compares characteristics and performance of five currently available systems, focusing on the information and feedback each system provides to the surgeon, what the systems allow the surgeon to modify during the operation, and how each system then aids execution of the surgical plan.Cite this article: Bone Jt Open 2023;4(1):13-18.

Basis for error in stereotactic and computer-assisted surgery in neurosurgical applications: literature review

Technological advancements in optoelectronic motion capture systems have allowed for the development of high-precision computer-assisted surgery (CAS) used in cranial and spinal surgical procedures. Errors generated sequentially throughout the chain of components of CAS may have cumulative effect on the accuracy of implant and instrumentation placement - potentially affecting patient outcomes. Navigational integrity and maintenance of fidelity of optoelectronic data is the cornerstone of CAS. Error reporting measures vary between studies. Understanding error generation, mechanisms of propagation, and how they relate to workflow can assist clinicians in error mitigation and improve accuracy during navigation in neurosurgical procedures. Diligence in planning, fiducial positioning, system registration, and intra-operative workflow have the potential to improve accuracy and decrease disparity between planned and final instrumentation and implant position. This study reviews the potential errors associated with each step in computer-assisted surgery and provides a basis for disparity in intrinsic accuracy versus achieved accuracy in the clinical operative environment.

Comparison of patient reported outcomes after robotic versus manual total knee arthroplasty in the same patient undergoing staged bilateral knee arthroplasty

Background

Robotic-assisted total knee arthroplasty (RATKA) has been proven to improve accuracy of component positioning and reducing alignment target outliers. However, the clinical benefit of robotics is often debated. Recent studies have shown reduced pain and faster recovery in the immediate post-operative period and may be associated with improved PROMs and satisfaction. The aim of this study was to assess PROMs and satisfaction in a unique patient population undergoing bilateral staged TKA to compare manual (MTKA) and RATKA in the same patient.

Methods

55 patients underwent bilateral staged TKA, performed by a single surgeon at a single institute. Patients who underwent TKA for the first knee with manual technique and RATKA for the second side, were eligible for inclusion in the study. Primary outcome assessed was the Oxford Knee Score and secondary outcomes included the Forgotten Joint Score (FJS), patient satisfaction, mean duration for independent ambulation after TKA, and patient perspectives on recovery evaluated with a questionnaire.

Results

Both RATKA and MTKA were associated with comparable PROMs. Though RATKA was associated with improved joint perception (Mean FJS after MTKA surgery was 70.3 (SD = 10.66) and significantly lower than the mean FJS after RATKA (73, SD = 10.95, p-value < 0.01), but the difference was not clinically relevant. A higher proportion of patients were more likely to be very satisfied or satisfied after RATKA. A significant proportion of patients felt the knee operated with RATKA was less painful and felt more natural compared to MTKA at final follow-up (p < 0.01). Majority of patients would undergo RATKA again and recommend robotic-TKA to others.

Conclusion

Robotic-assisted surgery was associated with improved patient satisfaction, faster independent ambulation compared to manual techniques. PROMs however, were comparable without clinically significant differences. Patients preferred robotic-assisted surgery, with a significantly higher proportion perceiving knee operated by RATKA felt more natural.

Where are We Now and What are We Hoping to Achieve with Robotic Total Knee Arthroplasty? A Critical Analysis of the Current Knowledge and Future Perspectives

Robotic-assisted total knee arthroplasty (rTKA) has been developed to improve knee kinematics and functional outcomes, expedite recovery, and improve implants long-term survivorship. Robotic devices are classified into active, semi-active, and passive, based on their degree of freedom. Their capacity to provide increased accuracy in implants positioning with reduced radiographic outliers has been widely proved. However, these early advantages are yet to be associated with long-term survivorship. Moreover, multiple drawbacks are still encountered including a variable learning curve, increased setup and maintenance costs, and potential complications related to the surgical technique. Despite recent technologies applied to TKA have failed to prove substantial improvements, robotic-assisted surgery seems to be here to stay and revolutionize the field of TKA. To support its consistent usage on a daily basis, long-term results are still awaited, and further improvements are necessary to reduce the expenses related to it.

Impact of a Digital Balancing Tool on Femur and Tibial First Total Knee Arthroplasty: A Prospective Nonrandomized Controlled Trial

Background

Recent developments in intra-operative sensor technology provide surgeons with predictive and real-time feedback on joint balance. It remains unknown, however, whether these technologies are better suited to femur-first or tibia-first workflows. This study investigates the balance accuracy, precision and early patient outcomes between the femur-first and tibial-first workflows using a digital gap-balancing tool.

Methods

One-hundred six patients had posterior cruciate ligament sacrificing total knee arthroplasty using a digital joint tensioner. The participants were divided into 4 groups with different visibility to balance data 1) Femur-first blinded data, 2) Femur-first not blinded data, 3) Tibia-first blinded data, 4) Tibia-first not blinded data with predictive balancing. Knee Injury and Osteoarthritis Outcome Score and University of California at Los Angeles activity level were recorded at 1-year.

Results

Group 4 reported less midflexion imbalance (40°) compared to all other groups (1: 1.5 mm, 2: 1.7 mm, 3: 1.6 mm, 4: 1.0 mm, P < .031) and reduced variance compared to all other groups at 40° and 90° (P < .012), resulting in an increased frequency of joints balanced within 2 mm throughout flexion in group 4 (1: 69%, 2: 65%, 3: 67%, 4: 91%, P < .006). No differences were found between 3-month, 6-month, or 1-year outcome scores between technique.

Conclusions

Improvements in balance were observed in midflexion instability and balance variability throughout flexion when a tibia-first approach in combination with a digital balancing tool was used. The combination of a digital balancing tool and a tibia-first approach allowed a target joint balance to be achieved more accurately compared to a non-sensor augmented or femur-first approach.

The evolution of robotic systems for total knee arthroplasty, each system must be assessed for its own value: a systematic review of clinical evidence and meta-analysis

INTRODUCTION

Robotic systems have been introduced to improve the precision of total knee arthroplasty. However, different robotic systems are available, each with unique features used to plan and execute the surgery. As such, due to this diversity, the clinical evaluation of each robotic platform should be separated.

METHODS

An extensive literature search of PubMed, Medline, Embase and Web of Science was conducted with subsequent meta-analysis. Randomised controlled trials, comparative studies, and cohort studies were included regarding robot-assisted total knee arthroplasty. Evaluated outcomes included clinical results, surgical precision, ligament balance, surgical time, learning curve, complications and revision rates. These were split up based on the robot-specific brand: ROBODOC (T-SOLUTION ONE), OMNIBOT, MAKO, NAVIO (CORI) and ROSA.

RESULTS

With a follow-up of more than 10 years, no improved clinical outcomes have been noted with the ROBODOC system compared to the conventional technique. If available, other platforms only present short-term clinical outcomes. Radiological outcomes are published for most robotic setups, demonstrating improved surgical precision compared to the conventional technique. Gap balance assessment is performed differently between all systems, leading to heterogeneous outcomes regarding its relationship on clinical outcomes. There is a similar learning curve based on operative time for all robotic platforms. In most studies, robot assistance requires longer operative time compared to the conventional technique. Complications and revision rates are published for ROBODOC and MAKO, without clear differences to conventional total knee arthroplasty.

CONCLUSION

The main finding of this systematic review is that the current evidence regarding each robotic system is diverse in quantity and quality. Each system has its own specificities and must be assessed for its own value. Regarding scientific literature, the generic term of robotic should be banned from the general conclusion.

LEVEL OF EVIDENCE

Systematic review level IV.

Patient Interest in Robotic Total Joint Arthroplasty Is Exponential: A 10-Year Google Trends Analysis

Background

The use of robotics in arthroplasty continues to increase. Patient demand, patient expectations, and patient-directed marketing by industry and care providers each likely contributes to its increasing popularity. Trends in patient interest have not been well described. We used the online Google Trends tool to analyze trends in national public interest toward robotic and nonrobotic arthroplasty between 2011 and 2021.

Material and methods

Google Trends online was queried for search terms related to nonrobotic hip and knee arthroplasty in addition to robotic hip, robotic knee, and general robotic arthroplasty between January 1, 2011, and December 31, 2021.

Results

Google Trends Data demonstrated a significant linear increase in online searches related to nonrobotic total knee and hip arthroplasty. Online search volume for robotic hip arthroplasty was significant and linear, while that of robotic knee arthroplasty was significant and exponential. When combined, robotic joint arthroplasty demonstrated an exponential trend over the 10-year period. This increase was noted to be statistically significant when compared with nonrobotic arthroplasty search volume.

Conclusion

Our study demonstrates that public interest in robotic total joint arthroplasty has increased significantly from 2011 through 2020. When compared with online search volume for conventional arthroplasty, this increasing growth is statistically significant. Public interest in robotic arthroplasty is anticipated to continue to increase, and care providers should be aware of this trend that impacts patient perceptions and expectations. Despite significant growth in interest for robotic arthroplasty, there is incomplete evidence supporting its use over nonrobotic arthroplasty. Additional high-quality studies are needed to inform provider decision-making and appropriately guide public interest in robot-assisted arthroplasty.

Comparison of serum inflammatory indicators and radiographic results in MAKO robotic-assisted versus conventional total knee arthroplasty for knee osteoarthritis: a retrospective study of Chinese patients

BACKGROUND

The purpose of this study was to compare the serum inflammatory indicators and radiographic results of conventional manual total knee arthroplasty (CM-TKA) with those of MAKO-robotic assisted total knee arthroplasty (MA-TKA).

METHODS

We retrospectively analysed 65 patients with knee osteoarthritis who underwent unilateral TKA from December 2020 to November 2021 in our department, which included 34 patients who underwent MA-TKA and 31 patients who underwent CM-TKA. The tourniquet time and estimated blood loss (EBL) were compared between the two groups. Knee function was evaluated using range of motion (ROM), functional score and pain score. Leukocytes, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), creatine kinase (CK), and neutrophil-to-lymphocyte ratio (NLR) were recorded at 3 time points (preoperative, and on the first and third postoperative days). The hip-knee-ankle angle (HKA) and the femoral and tibial component angles in the coronal and sagittal planes were used for postoperative radiographic evaluation.

RESULTS

The postoperative MA-TKA group had less EBL (496.9 ± 257.8 vs. 773.0 ± 301.3 ml, p < 0.001). There was no significant difference in knee function scores at 6 weeks postoperatively (p > 0.05). IL-6 levels were significantly lower in the MA-TKA group on the 1st postoperative day (11.4 (5.2, 21.0) vs. 24.6 (86.3, 170.8), p = 0.031). This difference in inflammatory indices became more pronounced at 72 hours after the operation because CRP, ESR, IL-6, and CK values were significantly lower in the MA-TKA group on the 3rd postoperative day (72 h) (p < 0.05). Postoperative radiographic examinations performed 2 days after the MA-TKA group suggested that only 2 cases of HKA had outlier values, which was remarkably better than the 12 cases found in the CM-TKA group (5.9% vs. 38.7%, p < 0.001). The frontal femoral component was significantly closer to the expected value of 90° in the MA-TKA group (90.9 (90.5, 92.3) vs. 92.4 (91.3, 93.7), p = 0.031). The remaining imaging evaluation parameters were not significantly different between the two groups (p > 0.05).

CONCLUSIONS

In Chinese patients with OA, there was a milder systemic inflammatory response in the early postoperative period after MA-TKA compared to that of CM-TKA, as well as better radiographic outcomes. However, the tourniquet time was prolonged, and no advantages were observed in terms of functional score or pain score in the short-term follow-up.