Aims. Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up. Methods. This prospective study included 16 patients undergoing robotic arm-assisted revision of UKA to TKA versus 35 matched patients receiving robotic arm-assisted primary TKA. In all study patients, the following data were recorded: operating time, polyethylene liner size, change in haemoglobin concentration (g/dl), length of inpatient stay, postoperative complications, and hip-knee-ankle (HKA) alignment. All procedures were performed using the principles of functional alignment. At most recent follow-up, range of motion (ROM), Forgotten Joint Score (FJS), and Oxford Knee Score (OKS) were collected. Mean follow-up time was 21 months (6 to 36). Results. There were no differences between the two treatment groups with regard to mean change in haemoglobin concentration (p = 0.477), length of stay (LOS, p = 0.172), mean polyethylene thickness (p = 0.065), or postoperative complication rates (p = 0.295). At the most recent follow-up, the primary robotic arm-assisted TKA group had a statistically significantly improved OKS compared with the revision UKA to TKA group (44.6 (SD 2.7) vs 42.3 (SD 2.5); p = 0.004) but there was no difference in the overall ROM (p = 0.056) or FJS between the two treatment groups (86.1 (SD 9.6) vs 84.1 (4.9); p = 0.439). Conclusion. Robotic arm-assisted revision of UKA to TKA was associated with comparable intraoperative blood loss, early postoperative rehabilitation, functional outcomes, and complications to primary robotic TKA at short-term follow-up. Robotic arm-assisted surgery offers a safe and reproducible technique for revising failed UKA to TKA. Cite this article: Bone Joint J 2024;106-B(7):680–687

Aims. The aims of this systematic review were to assess the learning curve of semi-active robotic arm-assisted total hip arthroplasty (rTHA), and to compare the accuracy, patient-reported functional outcomes, complications, and survivorship between rTHA and manual total hip arthroplasty (mTHA). Methods. Searches of PubMed, Medline, and Google Scholar were performed in April 2020 in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Search terms included “robotic”, “hip”, and “arthroplasty”. The criteria for inclusion were published clinical research articles reporting the learning curve for rTHA (robotic arm-assisted only) and those comparing the implantation accuracy, functional outcomes, survivorship, or complications with mTHA. Results. There were 501 articles initially identified from databases and references. Following full text screening, 17 articles that satisfied the inclusion criteria were included. Four studies reported the learning curve of rTHA, 13 studies reported on implant positioning, five on functional outcomes, ten on complications, and four on survivorship. The meta-analysis showed a significantly greater number of cases of acetabular component placement in the safe zone compared with the mTHA group (95% confidence interval (CI) 4.10 to 7.94; p < 0.001) and that rTHA resulted in a significantly better Harris Hip Score compared to mTHA in the short- to mid-term follow-up (95% CI 0.46 to 5.64; p = 0.020). However, there was no difference in infection rates, dislocation rates, overall complication rates, and survival rates at short-term follow-up. Conclusion. The learning curve of rTHA was between 12 and 35 cases, which was dependent on the assessment goal, such as operating time, accuracy, and team working. Robotic arm-assisted total hip arthroplasty was associated with improved accuracy of component positioning and functional outcome, however no difference in complication rates or survival were observed at short- to mid-term follow-up. Overall, there remains an absence of high-quality level I evidence and cost analysis comparing rTHA and mTHA. Cite this article: Bone Joint J 2021;103-B(6):1009–1020

Objectives. This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group. Methods. A total of 139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided robotic arm-assisted system. Outcome measures included the American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score, Hospital Anxiety Depression Scale, University of California at Los Angeles (UCLA) activity scale, Short Form-12, Pain Catastrophising Scale, somatic disease (Primary Care Evaluation of Mental Disorders Score), Pain visual analogue scale, analgesic use, patient satisfaction, complications relating to surgery, 90-day pain diaries and the requirement for revision surgery. Results. From the first post-operative day through to week 8 post-operatively, the median pain scores for the robotic arm-assisted group were 55.4% lower than those observed in the manual surgery group (p = 0.040). At three months post-operatively, the robotic arm-assisted group had better AKSS (robotic median 164, interquartile range (IQR) 131 to 178, manual median 143, IQR 132 to 166), although no difference was noted with the OKS. At one year post-operatively, the observed differences with the AKSS had narrowed from a median of 21 points to a median of seven points (p = 0.106) (robotic median 171, IQR 153 to 179; manual median 164, IQR 144 to 182). No difference was observed with the OKS, and almost half of each group reached the ceiling limit of the score (OKS > 43). A greater proportion of patients receiving robotic arm-assisted surgery improved their UCLA activity score. Binary logistic regression modelling for dichotomised outcome scores predicted the key factors associated with achieving excellent outcome on the AKSS: a pre-operative activity level > 5 on the UCLA activity score and use of robotic-arm surgery. For the same regression modelling, factors associated with a poor outcome were manual surgery and pre-operative depression. Conclusion. Robotic arm-assisted surgery results in improved early pain scores and early function scores in some patient-reported outcomes measures, but no difference was observed at one year post-operatively. Although improved results favoured the robotic arm-assisted group in active patients (i.e. UCLA ⩾ 5), these do not withstand adjustment for multiple comparisons. Cite this article: M. J. G. Blyth, I. Anthony, P. Rowe, M. S. Banger, A. MacLean, B. Jones. Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial. Bone Joint Res 2017;6:631–639. DOI: 10.1302/2046-3758.611.BJR-2017-0060.R1

Aims

This systematic review aims to compare the precision of component positioning, patient-reported outcome measures (PROMs), complications, survivorship, cost-effectiveness, and learning curves of MAKO robotic arm-assisted unicompartmental knee arthroplasty (RAUKA) with manual medial unicompartmental knee arthroplasty (mUKA).

Aims

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

Aims

The primary aim of this study was to compare the hip-specific functional outcome of robotic assisted total hip arthroplasty (rTHA) with manual total hip arthroplasty (mTHA) in patients with osteoarthritis (OA). Secondary aims were to compare general health improvement, patient satisfaction, and radiological component position and restoration of leg length between rTHA and mTHA.

Total hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies. Cite this article: Bone Joint J 2024;106-B(2):114–120

Aims. Unicompartmental knee arthroplasty (UKA) is a bone-preserving treatment option for osteoarthritis localized to a single compartment in the knee. The success of the procedure is sensitive to patient selection and alignment errors. Robotic arm-assisted UKA provides technological assistance to intraoperative bony resection accuracy, which is thought to improve ligament balancing. This paper presents the five-year outcomes of a comparison between manual and robotically assisted UKAs. Methods. The trial design was a prospective, randomized, parallel, single-centre study comparing surgical alignment in patients undergoing UKA for the treatment of medial compartment osteoarthritis (ISRCTN77119437). Participants underwent surgery using either robotic arm-assisted surgery or conventional manual instrumentation. The primary outcome measure (surgical accuracy) has previously been reported, and, along with secondary outcomes, were collected at one-, two-, and five-year timepoints. Analysis of five-year results and longitudinal analysis for all timepoints was performed to compare the two groups. Results. Overall, 104 (80%) patients of the original 130 who received surgery were available at five years (55 robotic, 49 manual). Both procedures reported successful results over all outcomes. At five years, there were no statistical differences between the groups in any of the patient reported or clinical outcomes. There was a lower reintervention rate in the robotic arm-assisted group with 0% requiring further surgery compared with six (9%) of the manual group requiring additional surgical intervention (p < 0.001). Conclusion. This study has shown excellent clinical outcomes in both groups with no statistical or clinical differences in the patient-reported outcome measures. The notable difference was the lower reintervention rate at five years for roboticarm-assisted UKA when compared with a manual approach. Cite this article: Bone Joint J 2021;103-B(6):1088–1095

Introduction. The objectives of this study were to compare the systemic inflammatory reaction, localised thermal response and macroscopic soft tissue injury outcomes in conventional jig-based total knee arthroplasty (conventional TKA) versus robotic total knee arthroplasty (robotic TKA). Methods. This prospective randomised controlled trial included 30 patients with symptomatic knee osteoarthritis undergoing conventional TKA versus robotic TKA. Predefined serum markers of inflammation and localised knee temperature were collected preoperatively and postoperatively at 6 hours, day 1, day 2, day 7, and day 28 following TKA. Blinded observers used the Macroscopic Soft Tissue Injury (MASTI) classification system to grade intraoperative periarticular soft tissue injury and bone trauma. Plain radiographs were used to assess the accuracy of achieving the planned limb alignment and implant positioning in both treatment groups. Results. Conventional TKA and robotic TKA had comparable changes in the postoperative systemic inflammatory reaction and localised thermal response at 6 hours, day 1, day 2 and day 28 after surgery. Robotic TKA had reduced levels of interleukin-6 (p<0.001), tumour necrosis factor-α (p=0.021), erythrocyte sedimentation rate (p=0.001), C-reactive protein (p=0.004), and creatine kinase (p=0.004) at day 7 after surgery compared to conventional TKA. Robotic TKA was associated with improved intraoperative preservation of the periarticular soft tissue envelope (p<0.001) and reduced bone trauma (p=0.015) compared to conventional TKA. Robotic TKA improved accuracy of achieving the planned limb alignment (p<0.001), femoral component positioning (<0.001), and tibial component positioning (<0.001) compared to conventional TKA. Conclusion. Robotic TKA was associated with a transient reduction in the early (day 7) postoperative inflammatory response but there was no difference in the immediate (<48 hours) or late (day 28) postoperative systemic inflammatory responses compared to conventional TKA. Robotic TKA was associated with decreased iatrogenic periarticular soft tissue injury, reduced bone trauma and improved accuracy of implant positioning compared to conventional TKA

The MAKO Robotic arm is a haptic robotic system that can be used to optimise performance during total hip arthroplasty (THA). We present the outcome of the first 40 robotic cases performed in an NHS foundation trust along with the technique of performing robotic THA in our unit. Forty consecutive patients undergoing robotic THA (rTHA) were compared to a case matched group of patients undergoing manual THA (m-THA). 2:1 blinded case matching was performed for age, sex, implants used (Trident uncemented socket and cemented Exeter stem, Stryker Mahwah, NJ, US) and surgeon grade. Comparisons were made for radiological positioning of implants, including leg length assessment, and patient reported functional outcome (PROMS). Pre- and post-operative radiographs were independently analysed by 2 authors. All patients underwent THA for a primary diagnosis of osteoarthritis. No significant difference between groups was identified for post-operative leg length discrepancy (LLD) although pre-operatively a significantly higher LLD was highlighted on the MAKO group, likely due to patient selection. Significantly lower post-operative socket version was identified in the MAKO cohort although no difference in post-operative cup inclination was noted. However, there was significantly larger variance in post-op LLD (p=0.024), cup version (p=0.004) and inclination (p=0.05) between groups indicating r-THA was significantly less variable (Levene's test for homogeneity of variance). There was no significant difference in the number of cases outside of Lewinnek's ‘safe’ zone for inclination (p=0.469), however, there were significantly more cases outside Lewinnek's ‘safe’ zone for version (12.5% vs 40.3%, p=0.002) in the m-THA group. We report the commencement of performance of MAKO robotic THA in an NHS institution. No problems with surgery were reported during our learning curve. Robotic THA cases had less variability in terms of implant positioning suggesting that the MAKO robot allows more accurate, less variable implant positioning with fewer outliers. Longer term follow-up of more cases is needed to identify whether this improved implant positioning has an effect on outcomes, but the initial results seem promising

Background. Stability of total knee arthroplasty (TKA) is dependent on correct and precise rotation of the femoral component. Multiple differing surgical techniques are currently utilized to perform total knee arthroplasty. Accurate implant position have been cited as the most important factors of successful TKA. There are two techniques of achieving soft gap balancing in TKA; a measured resection technique and a balanced gap technique. Debate still exists on the choice of surgical technique to achieve the optimal soft tissue balance with opinions divided between the measured resection technique and the gap balance technique. In the measured resection technique, the bone resection depends on size of the prosthesis and is referenced to fixed anatomical landmarks. This technique however may have accompanying problems in imbalanced patients. Prediction of gap balancing technique, tries to overcome these fallacies. Our aim in this study was twofold: 1) To describe our methodology of ROBOTIC TKA using prediction of gap balancing technique. 2) To analyze the clinico-radiological outcome our technique comparison of meseaured resection ROBOTIC TKA after 1year. Methods. Patients that underwent primary TKA using a robotic system were included for this study. Only patients with a diagnosis of primary degenerative osteoarthritis with varus deformity and flexion deformity of were included in this study. Patients with valgus deformity, secondary arthritis, inflammatory arthritis, and severe varus/flexion deformity were excluded. Three hundred ten patients (319 knees) who underwent ROBOTIC TKA using measured resection technique from 2004 – 2009. Two hundred twenty (212 knees) who underwent ROBOTIC TKA using prediction of gap balancing technique from 2010 – 2012. Clinical outcomes including KS and WOMAC scores, and ranges of motion and radiological outcomes including mechanical axis, prosthesis alignments, flexion varus/valgus stabilities were compared after 1year. Results. Leg mechanical axes were significantly different at follow-up 1year versus preoperative values, the mean axes in the Robotic-TKA with measured resection technique and Robotic-TKA with prediction of gap balancing technique improved from 9.6±5.0° of varus to 0.5±1.9° of varus, and from 10.6±5.5° to 0.4±1.3° of varus (p<0.001), respectively. However, no significant intergroup differences were found between mechanical axis or coronal alignments of femoral or tibial prostheses (pï¼ï¿½0.05). Mean varus laxities at 90° of knee flexion in measured resection and gap prediction technique group were 6.4° and 5.3°, respectively, and valgus laxities were 6.2 and 5.2 degrees, respectively, with statistical significance (p=0.045 and 0.032, respectively). KS knee and function scores and WOMAC scores were significantly improved at follow-up 1year (pï¼ï¿½0.05). However, no significant difference was found between the Robotic-TKA with measured resection technique and Robotic-TKA with prediction of gap balancing technique for any clinical outcome parameter at follow-up 1year (pï¼ï¿½0.05). Conclusions. Robotic assisted TKA using measured resection or gap prediction technique provide adequate and practically identical levels of flexion stability at 90° of knee flexion with accurate leg and prosthesis alignment. But, Robotic TKA using measured resection technique have less than flexion stability compared with gap prediction technique with statistical significance after follow-up 1year

The introduction of robotics for total knee arthroplasty (TKA) into the operating theatre is often associated with a learning curve and is potentially associated with additional complications. The purpose of this study was to determine the learning curve of robotic-assisted (RA) TKA within a multi-surgeon team. This prospective cohort study included 83 consecutive conventional jig-based TKAs compared with 53 RA TKAs using the Robotic Surgical Assistant (ROSA) system (Zimmer Biomet, Warsaw, Indiana, USA) for knee osteoarthritis performed by three high-volume (> 100 TKA per year) orthopaedic surgeons. Baseline characteristics including age, BMI, sex and pre-operative Kellgren-Lawrence grade were well-matched between the conventional and RA TKA groups. Cumulative summation (CUSUM) analysis was used to assess learning curves for operative times for each surgeon. Peri-operative and delayed complications were reviewed. The CUSUM analysis for operative time demonstrated an inflexion point after 5, 6 and 15 cases for each of the three surgeons, or 8.7 cases on average. There were no significant differences (p = 0.53) in operative times between the RA TKA learning (before inflexion point) and proficiency (after inflexion point) phases. Similarly, the operative times of the RA TKA group did not differ significantly (p = 0.92) from the conventional TKA group. There was no discernible learning curve for the accuracy of component planning using the RA TKA system. The average length of post-operative follow-up was 21.3 ± 9.0 months. There was no significant difference (p > 0.99) in post-operative complication rates between the groups. The introduction of the RA TKA system was associated with a learning curve for operative time of 8.7 cases. Operative times between the RA TKA and conventional TKA group were similar. The short learning curve implies this RA TKA system can be adopted relatively quickly into a surgical team with minimal risks to patients

Introduction. Robotics have been applied to total knee arthroplasty (TKA) to improve surgical precision in component placement and joint function restoration. The purpose of this study was to evaluate prosthetic component alignment in robotic arm-assisted (RA)-TKA performed with functional alignment and intraoperative fine-tuning, aiming for symmetric medial and lateral gaps in flexion/extension. It was hypothesized that functionally aligned RA-TKA the femoral and tibial cuts would be performed in line with the preoperative joint line orientation. Methods. Between September 2018 and January 2020, 81 RA cruciate retaining (CR) and posterior stabilized (PS) TKAs were performed at a single center. Preoperative radiographs were obtained, and measures were performed according to Paley's. Preoperatively, cuts were planned based on radiographic epiphyseal anatomies and respecting ±3° boundaries from neutral coronal alignment. Intraoperatively, the tibial and femoral cuts were modified based on the individual soft tissue-guided fine-tuning, aiming for symmetric medial and lateral gaps in flexion/extension. Robotic data were recorded. Results. A total of 56 RA-TKAs performed on varus knees were taken into account. On average, the tibial component was placed at 1.9° varus (SD 0.7) and 3.3° (SD 1.0) in the coronal and sagittal planes, respectively. The average femoral component alignment, based on the soft tissue tensioning with spoons, resulted as follows: 0.7° varus (SD 1.7) in the coronal plane and 1.8° (SD 2.1) of external rotation relative to surgical transepicondylar axis in the transverse plane. A statistically significant linear direct relationship was demonstrated between radiographic epiphyseal femoral and tibial coronal alignment and femoral (r=0.3, p<0.05) and tibial (r=0.3, p<0.01) coronal cuts, resepctively. Conclusion. Functionally aligned RA-TKA performed in varus knees, aiming for ligaments’ preservation and balanced flexion/extension gaps, provided joint line respecting femoral and tibial cuts on the coronal plane

Robotic assisted surgery aims to reduce surgical errors in implant positioning and better restore native hip biomechanics compared to conventional techniques for total hip arthroplasty (THA). The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual THA versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, cup inclination, cup version, and leg-length correction. This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. All operative procedures were undertaken by a single surgeon using the minimally-invasive posterior approach. Two independent blinded observers recoded all radiological outcomes of interest using plain radiographs. Patients in both treatment groups were well-matched for age, gender, body mass index, laterality of surgery, and ASA scores. Interclass correlation coefficient was 0.92 (95% CI: 0.84 – 0.95) for intra-observer agreement and 0.88 (95% CI: 0.82–0.94) for inter-observer agreement in all study outcomes. Robotic THA was associated with improved accuracy in restoring the native horizontal (p<0.001) and vertical (p<0.001) centres of rotation, and improved preservation of the patient's native combined offset (P<0.001) compared to conventional THA. Robotic THA improved accuracy in positioning of the acetabular cup within the combined safe zones of inclination and anteversion described by Lewinnek et al (p=0.02) and Callanan et al (p=0.01) compared to conventional THA (figures 1–2). There was no difference between the two treatment groups in achieving the planned leg-length correction (p=0.10). Robotic-arm assisted THA was associated with improved accuracy in restoring the native centre of rotation, better preservation of the combined offset, and more precise acetabular cup positioning within the safe zones of inclination and anteversion compared to conventional manual THA. Robotic-arm assisted THA enables improved preservation of native hip biomechanics compared to conventional manual THA. For any figures or tables, please contact authors directly: . fsh@fareshaddad.net

Robotic arm-assisted total knee replacement is performed as a semi-active system in which haptic guidance is used to precisely position and align components. This is based on pre-operative planning based on CT imaging and can be modified as needed throughout the procedure. This technology, as shown with unicompartmental arthroplasty, is more accurate than conventional and even computer navigated instrumentation and will decrease variability. The knee can be planned to a neutral mechanical alignment. Intra-operatively, the computer will demonstrate compartment gap measurements to assist with soft tissue balancing. Alternatively, limb and component alignment can be accurately adjusted several degrees off the neutral axis to balance the knee and avoid or minimise soft tissue releases. This allows a more constitutional alignment within the alignment parameters accepted by the surgeon. This technique was utilised commonly in the first 60 robotic total knee replacements performed. We will now have the ability to collect accurate component positioning, alignment, and soft tissue balance data that can be correlated to outcomes of total knee replacements

Robotic and navigated TKA procedures have been introduced to improve component placement precision for the purpose of improving implant survivorship and other clinical outcomes. Although numerous studies have shown enhanced precision in placing components, adoption of technology-assistance (TA) for TKA has been relatively slow. One reason for this has been the difficulty in demonstrating the cost-effectiveness of implementing TA-TKA systems and assessing their impact on revision rates. In this study, we aimed to use a simulation approach to answer the following questions: (1) Can we determine the distribution of likely reductions in TKA revision rates attributable to TA-TKA in an average US patient population? And, (2) What reduction in TKA revision rates are required to achieve economic neutrality?. In a previous study, we developed a method for creating large sets of simulated TKA patient populations with distributions of patient-specific factors (age at index surgery, sex, BMI) and one surgeon-controlled factor (coronal alignment) drawn from registry data and published literature. Effect sizes of each factor on implant survival was modeled using large clinical studies. For 10,000 simulated TKA patients, we simulated 20,000 TKA surgeries, evenly split between groups representing coronal alignment precisions reported for manual (±3°) and TA-TKA (±1.0°), calculating the patient-specific survival curve for each group. Extending our previous study, we incorporated the probability of each patient's expected survival into our model using publicly available actuarial data. This allowed us to calculate a patient-specific estimate of the Reduction in Lifetime Risk of Revision (RLRR) for each simulated patient. Our analysis showed that 90% of patients will achieve an RLRRof 1.5% or less in an average US TKA population. We then conducted a simplified economic analysis with the goal of determining the net cost of using TA-TKA per case when factoring in future savings by TKA revision rates. We assumed an average cost of revision surgery to be $75,000 as reported by Delanois (2017) and an average added cost incurred by TA-TKA to be $6,000 per case as reported by Antonis (2019). We estimate the net cost per TA-TKA case (CNet) to be the added cost per TA-TKA intervention (CInt), less the cost of revision surgery (CRev) multiplied by the estimated RLRR: CNet = CInt - CRev∗RLRR. We find that, under these assumptions, use of TA-TKA increases expected costs for all patients with an RLRR of under 8%. Based on these results, it appears that it would not be cost-effective to use TA-TKA on more than a small fraction of the typical US TKA patient population if the goal is to reduce overall costs through reducing revision risks. However, we note that this simulation does not consider other possible reported benefits of TA-TKA surgery, such as improved functional and pain outcome scores which may justify its use on other grounds. Alternative costs incurred by TA-TKA will be evaluated in a future study. To reach economic neutrality, TA-TKA systems either must reduce the added cost per intervention or increase RLRR by better addressing the root causes of revision

In this study we compare survivorship and patient reported outcome measures in robotically assisted versus conventional Total Hip Arthroplasty (THA). This paper investigates the hypothesis that implant survival and PROMS following THAs performed with robotic assistance were not different to outcomes following conventional THAs. Data included all patients undergoing THA for osteoarthritis between 19 April 2016 and 31 December 2020. Analysis of PROMS outcomes was restricted to those who had completed PROMS data preoperatively and at 6 months postoperatively. There were 157,647 procedures, including 3567 robotically assisted procedures, available for comparison of revision rates. 4557 procedures, including 130 robotically assisted procedures, had PROMS data available. The revision rate of primary THA performed with robotic assistance was not statistically different from THA performed by conventional methods (4 year cumulative percent revision 3.1% v 2.7%; HR = 1.05, p=0.67). The Oxford Hip Score, VAS for pain and the EQ-VAS score for overall health showed no statistically significant difference between the groups. The EQ-5D Utility Score showed an improved score (median score 1 v 0.88; OR = 1.58, p=0.007) for the robotically assisted group compared to the conventional group. Robotic assisted THA was not associated with significant improvement in early revision or joint-specific PROMs. The findings may have been biased, in either direction, by unmeasured patient, surgeon, hospital and prosthesis factors. The findings (including the difference in health-related quality of life) may have also been influenced by lack of blinding. Future research should include methods to minimise these biases

Introduction. This study sought to evaluate the patient experience and short-term clinical outcomes associated with the hospital stay of patients who underwent robotic arm-assisted total knee arthroplasty (TKA). These results were compared to a cohort of patients who underwent TKA without robotic assistance performed by the same surgeon. Methods. A cohort of consecutive patients undergoing primary TKA for the diagnosis of osteoarthritis by a single fellowship trained orthopaedic surgeon over a 39-month period was identified. Patients who underwent TKA during the year this surgeon transitioned his entire knee arthroplasty practice to robotic assistance were excluded to eliminate selection bias and control for the learning curve. A final population of 538 TKAs was identified. Of these, 314 underwent TKA without robotic assistance and 224 underwent robotic arm-assisted TKA. All patients received the same prosthesis and post-operative pain protocol. Patient demographic characteristics and short-term clinical data were analyzed. Results. Robotic arm-assisted TKA was associated with shorter length of stay (2.3 versus 2.6 days, p< 0.001), a 50% reduction in morphine milligram equivalent utilization (from 213 to 105, p< 0.001), decreased visual analog scale pain score on post-op day 1 and 2 (p< 0.001), and a mean increase in procedure time of 8.2 minutes (p=0.08). There were no post-operative infections in either cohort. Additionally, there were no significant differences in rates of manipulation under anesthesia, emergency department visits, readmissions, or return to the operating room. Conclusions. This analysis corroborates existing literature suggesting that robotic arm-assisted TKA can be correlated with improved short-term clinical outcomes. This study reports on a single surgeon's experience with regard to analgesic requirements, length of stay, pain scores, and procedure time following a complete transition to robotic arm-assisted TKA. These results underscore the importance of continued evaluation of clinical outcomes as robotic arthroplasty technology continues to grow. For any figures or tables, please contact authors directly

Introduction:. Computer-assisted surgery (CAS) aims to improve component positioning and mechanical alignment in Total Knee Arthroplasty (TKA). Robotic cutting-guides have been integrated into CAS systems with the intent to improve bone-cutting precision and reduce navigation time by precisely automating the placement of the cutting-guide. The objectives of this study were to compare the intra-operative efficiency and accuracy of a robotic-assisted TKA procedure to a conventional computer-assisted TKA procedure where fixed sequential cutting-blocks are navigated free-hand. Methods:. This was a retrospective study comparing two distinct cohorts: the control group consisted of patients undergoing TKA with conventional CAS (Stryker Universal Knee Navigation v3.1, Stryker Orthopaedics, MI) from May 2006 to September 2007; the study group consisted of patients undergoing TKA with a robotic cutting-guide (Apex Robotic Technology, ART, OMNIlife Science, MA) from October 2010 to May 2012. Exclusion of patients with preexisting hardware in the joint or an absence of navigation data resulted in a total of 29 patients in the control group and 52 patients in the study group. Both groups were similar with respect to BMI, age, gender, and pre-operative alignment. All patients were operated on by a single surgeon at a single institution. The navigation log files were analyzed to determine the total navigation time for each case, which was defined as the time from the start of the acquisition of the hip center to the end of the final alignment analysis for both systems. The intraoperative final mechanical axis was also recorded. The tourniquet time (time of inflation prior to incision to deflation immediately after cement hardening) and hospitalization length were compared. Linear regression analysis was performed using R statistical software v2.12.1. Results:. Navigation times were on average 9.0 minutes shorter in the study group compared to the control group (95% CI: [4.0, 14.1], p = 0.0006). Average absolute intraoperative alignment was 0.5 degrees closer to neutral in the robotic group compared to the conventional CAS group (95% CI: [0.08, 0.95], p = 0.020). Tourniquet time was not significantly different between the two systems (0.2 min, 95% CI [−5.4, 5.9], p = 0.926). Patients in the study group were discharged 0.6 days earlier than patients in the control group (95% CI: [0.1, 1.1], p = 0.0122). Discussions:. Our results suggest that use of a robotic cutting-guide can decrease the time taken to navigate a TKA procedure in comparison to conventional free-hand navigation of multiple fixed cutting blocks, which is supported by previous studies [1]. However, this time savings did not translate into a reduction in the tourniquet time. We believe this may be due in part to the two different types of bone cement that were used during the distinct study periods, where the hardening time for the cement in the study group was estimated to be approximately 5 minutes longer. Conclusions:. In one surgeon's hands, use of a robotic cutting-guide decreased navigation time, improved intraoperative final alignment, and decreased hospitalization length when compared to conventional computer-assisted navigation in TKA

Purpose. The purpose of this study was to evaluate the postoperative maximal flexion of Robotic assisted TKA which does not increase the posterior condylar offset after surgery and compare CT and conventional radiography in measuring the posterior condylar offset changes. Materials and method. 50 knees of 37 patients who underwent Robotic TKA and underwent follow-up minimal one year were evaluated. CT based preoperative surgical planning system was designed not to increase posterior condylar offset (PCO) after surgery. Maximal flexion angle of the knee was evaluated at 1 year after surgery. The change in PCO and joint line on x-ray and CT were evaluated. Results. The mean preoperative knee flexion was 121° (sd: 9.21; range: 80–135), and it was improved to 125.3° (sd: 4.85; range: 115–140) postoperatively. On radiographic evaluation, the mean preoperative PCO was 26.4 mm (sd: 0.5; range: 14.8 mm to 36.3 mm) and the mean postoperative PCO was 23.0 mm (sd: 0.37; range: 16.0 mm to 34.3 mm). On CT evaluation, the mean medial PCO was 28.7± 2.4 mm preoperatively and 24.9± 2.2 mm postoperatively. The mean lateral PCO was 26.3± 2.4 mm preoperatively and 24.9± 2.2 mm postoperatively. There were no significant correlations between x-ray and CT measurement in PCO and joint line. There were no significant correlations between the changes in the posterior condylar offsets and the postoperative knee flexion. Conclusion. After Robotic assisted TKA which is planned not to increase the medial and lateral posterior condylar offset, satisfactory maximal flexion angle of the knee was gained in all patients. Changes in medial and lateral posterior condylar offsets were not correlated with the postoperative knee flexion angle. And changes in PCO and joint line measured by x-ray did not reflect those of the medial and lateral condyle, and joint line on CT

The objective of this study was to compare differences in alignment following robotic arm-assisted bi-unicompartmental knee arthroplasty (Bi-UKA) and conventional total knee arthroplasty (TKA). This was a prospective, randomised controlled trial of 70 patients. 39 TKAs were implanted manually, as per standard protocol at our institution, and 31 Bi-UKA patients simultaneously received fixed-bearing medial and lateral UKAs, implanted using robotic arm-assistance. Preoperative and 3-month postoperative CT scans were analysed to determine hip knee ankle angle (HKAA), medial distal femoral angle (MDFA), and medial proximal tibial angle (MPTA). Analysis was repeated for 10 patients by a second rater to validate measurement reliability by calculating the intra-class correlation coefficient (ICC). Mean change in HKAA towards neutral was 2.7° in TKA patients and 2.3° in Bi-UKA patients (P=0.6). Mean change in MDFA was 2.5° for TKA and 1.0° for Bi-UKA (P<0.01). Mean change in MPTA was 3.7° for TKA and 0.8° for Bi-UKA (P<0.01). Mean postoperative MDFA and MPTA for TKAs were 89.8° and 89.6° respectively, indicating orientation of femoral and tibial components perpendicular to the mechanical axis. Mean postoperative MDFA and MPTA for Bi-UKAs were 91.0° and 86.9° respectively, indicating a more oblique joint line orientation. Inter-rater agreement was excellent (ICC>0.99). Early functional activities, according to the new Knee Society Scoring System, favoured Bi-UKAs (P<0.05). Robotic arm-assisted, cruciate-sparing Bi-UKA better maintains the natural anatomy of the knee in the coronal plane and may therefore preserve normal joint kinematics, compared to a mechanically aligned TKA. This has been achieved without significantly altering overall HKAA

Introduction. Total knee arthroplasty (TKA) using conventional instrumentation has been shown to be a safe and effective way of treating end stage osteoarthritis by restoring function and alleviating pain. As robotic technology is developed to assist surgeons with intra-operative decision making such as joint balancing and component positioning, the safety of these advancements must be established. Furthermore, functional recovery and clinical outcomes should achieve comparable results to the gold standard of conventional instrumentation TKA. Methods. Eighty-seven subjects (89 knees) underwent robotic arm assisted TKA by one of three investigators as part of an FDA and IRB approved Investigational Device Exemption (IDE). To achieve the primary endpoint of intra-operative patient safety using a robotic arm assisted cutting tool, the investigators completed questionnaires to assess a series of complications related to soft tissue damage associated with conventional TKA. Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Knee Society Knee Scores (KSS) were collected pre-operatively and at three month follow-up. Results. The average subject age was 65.8 ± 8.5 and the average BMI was 31.4 ± 5.7. 55% of the subjects were female. No subject experienced any of the rare intra-operative complications that comprise the primary safety endpoint. The average WOMAC score improvement from pre-operative to three months was 33.1 ± 20.04 (p<0.0001). The average KSS Knee score improvement was 46.1 ± 19.7 (p<0.0001). Subjects recovered their pre-operative range of motion by three months post-operative. Conclusion. Results from this prospective robotic arm assisted trial indicated greater intra-operative safety in blood loss and ligamentous damage when compared to conventional TKA. Subjects had excellent return to function and pain relief by three months as indicated by the KSS and WOMAC scores. Robotic technologies should be considered a safe and effective method in total joint restoration

Introduction:. Cam type femoroacetabular impingement (FAI) may lead to osteoarthritis (OA)[1]. In 2D studies, an alpha angle greater than 55° was considered abnormal however limitations of 2D alpha angle measurement have led to the development of 3D methods [2–4]. Failure to completely address the bony impingement lesions during surgery has been the most common reason for unsuccessful hip arthroscopy surgery [5]. Robotic technology has facilitated more accurate surgery in comparison to the conventional means. In this study we aim to assess the potential application of robotic technology in dealing with this technically challenging procedure of cam sculpting surgery. Methods:. CT scans of three patients' hips with severe cam deformity (A, B and C models) were obtained and used to construct 3D dry bone models. A 3D surgical plan was made in custom written software. Each 3D plan was imported into the Acrobot Sculptor robot and bone resection was carried out. In total, 42 femoral models were sculpted (14/subset), thirty of which were performed by a single operator and the remaining 12 femurs were resected by two other operators. CT of the pre/post resected specimens was segmented and a 3D alpha angle and head neck ratios were measured [3–4] and compared using Mann-Whitney U test. Coefficient of variation (CV) was used to determine the degree of variation between the mean and maximum observed alpha angles for inter and intra observer repeatability. Results:. The maximal alpha angle in cam A, B and C (90.8°, 91.3° and 87.1°). There was significant reduction (p < 0.001) in maximum alpha angles post-operatively within all three models when compared to original model (Figure 1). The HNRs for cam A, B and C prior to surgery were found to be 3.2, 3.4 and 3.1 respectively that were reduced to a mean of 3.0 ± 0.1, 3.1 ± 0.1 and 3.1 ± 0.0, following resection surgery. The results of the intra and inter-observer repeatability study found good reproducibility (CV<10%) of the maximum and mean alpha angles between the 12 resected femurs. Discussion:. In this study we evaluated the use of robotic system to perform cam correction surgery by evaluating the 3D morphology of head/neck prior to and post surgery. With existing surgical options there is a potential for under or over-resection of the cam lesion, which runs the risk of the need for further surgery or rarely neck fracture and dislocation. Based on the calculated alpha angles and HNRs we have proved that we have successfully performed the surgery by avoiding under and over resection respectively. Amore accurate bony resection performed here may minimize the complications due to over and under resection and hence will decrease the burden on the health service

Abstract

With the approval of our institute, we reviewed all the robot-assisted hip revision during October 2019 and August 2021. MAKO joint arthroplasty system was used to perform the hip revision surgery.

Seventy-one robot-assisted hip revision cases were included. Cup revisions were carried out in 68 patients while stem revisions were also carried out in 68 patients. Three types of registration techniques (extra acetabular bone surface based, liner based, metal shell based or cage surface based) on the acetabular side. The extra acetabular bone surface was the commonest used for registration (48/70, 68.6%, mean accuracy 0.37mm), followed by liner surface (11/70, 15.7%, mean accuracy 0.36mm), acetabulum cup (10/70, 14.3%, mean accuracy 0.37mm), and cage surface (1/70, 1.4%, accuracy 0.40mm). We succeeded cup registration and robotic arm guided cup insertion in all the cases. The average cup inclination and anteversion after revision were 40.87°±4.39° and 13.87°±4.24°, respectively. Cups in 62 cases (62/68, 91.2%) were within the Lewinnek safe zone while in 55 cases (55/68, 80.9%) were within the Callanan safe zone.

The Mako robot-assisted system could bring favorable cup reconstruction in hip revision with acceptable surgical time and blood loss. Accurate registration could be achieved by different methods.

Unicompartmental knee arthroplasty (UKA) is an increasingly attractive and clinically successful treatment for individuals with isolated medial compartment disease who demand high levels of function. A major challenge with UKA is to place the components accurately so they are mechanically harmonious with the retained joint surfaces, ligaments and capsule. Misalignment of UKA components compromises clinical outcomes and implant longevity. Cobb et al. (JBJS-Br 2006) showed that robot-assisted placement of UKA components was more accurate than traditional techniques, and subsequently that the clinical outcomes were improved. Cobb’s method, however, employed rigid intraoperative stabilization of the bones in a stereotactic frame, which is impractical for routine clinical use. Robotic systems have now advanced to include dynamic bone tracking technologies so that rigid fixation is no longer required. The question is -Do these robotic systems with dynamic bone tracking provide the same accuracy advantages demonstrated with robotic systems with rigidly fixed bones? We compared robot-assisted and traditionally instrumented UKA in six bilateral pairs of cadaver specimens. In all knees, a CT-based preoperative plan was performed to determine the ideal positions and orientations for the implant components. Traditional manual instruments were utilized with a tissue-sparing approach to implant one knee of each pair. A haptic robotic system acting as a virtual cutting guide was used to perform the robot-assisted UKA, again with a tissue-sparing approach. Postoperative CT scans were obtained from all knees, and the 3D placement errors were quantified using 3D-to-3D registration of implant and bone models to the reconstructed CT volumes. The magnitudes of femoral implant orientation error were significantly smaller for the robot-assisted implants compared to traditionally implanted components (4° vs 11°, p< 0.001), but the magnitudes of femoral placement error did not reach significance (3mm vs. 5mm, p=0.056). The magnitudes of tibial implant placement error were not significantly different (4mm vs. 5mm and 7° vs. 7°, p> 0.05). Well-placed UKA implants can provide durable and excellent functional results, which is an increasingly attractive option for young and active patients with severe compartmental osteoarthritis who wish not to have or to delay a total knee replacement. Previous studies have demonstrated significant improvement in implant placement accuracy and clinical results with robot-assisted surgery using rigid bone fixation. This study demonstrates it is possible to achieve significant accuracy improvements with robot-assisted techniques allowing free bone movement. Additional larger trials will be required to determine if these differences are realized in clinical populations

Introduction and aims. Robotic Assisted Arthroplasty (RAA) is increasingly proliferative in the international orthopaedic environment. Traditional bibliometric methods poorly assess the impact of surgical innovations such as robotic technology. Progressive Scholarly Acceptance (PSA) is a new model of bibliographic analysis which quantitatively evaluates the impact of robotic technology in the orthopaedic scientific community. Methods. A systematic literature search was conducted to retrieve all peer-reviewed, English language publications studying robotic assisted hip and knee arthroplasty between 1992 and 2017. Review articles were excluded. Articles were classified as either “initial investigations” or “refining studies” according to the PSA model, described by Schnurman and Kondziolka. The PSA end-point is defined as the point in time when the number of studies focussed on refining or improving a novel technique (RAA) outnumbers the number of initial studies assessing its efficacy. Results. The study identified 73 original studies published since 1992 in the field of RAA. The procedures reported were total hip and total knee replacement, and uni-compartmental knee replacement. Publications originated from 17 countries and 117 organisations. Fifty percent of studies identified were published in the last 5 years at an average of 7 publications per year, compared to an average of 2.7 publications per year from 1992 to 2012. Fifty-eight publications (79.4%) were classified as initial investigations and 15 (20.5%) were classified as refining studies. Conclusions. PSA model analysis of RAA is indicative of a significant increase in published research, particularly over the last 5 years. However, the majority of publications are efficacious rather than technique refining. This implies that RAA has not reached the threshold of general acceptance by the Orthopaedic community

Introduction. Accurate component placement in total hip arthroplasty (THA) improves post-operative stability and reduces wear and aseptic loosening. Methods for achieving accurate stem placement have not been as extensively studied as cup placement. Objectives. The purpose of this study is to determine how consistently femoral stem version can be corrected to an ideal of 15 +/− 5 degrees using robotic guidance. Furthermore, the study aims to identify other factors related to approach and patient demographics, which may influence the degree of correction obtained. Methods. 175 consecutive patients who underwent MAKO robotic guidance THA were included in the study with a mean age of 57.9 years and a mean body mass index (BMI) of 30.41kg/m2. 48% of the population was male and 74% of the procedures were performed through an anterior approach. The absolute difference between 15 degrees of anteversion and native femoral version as well as 15 degrees of anteversion and femoral stem version was calculated for each patient. A smaller absolute value post-operatively reflects a closer femoral stem version to a target of 15 degrees. Results. The mean native femoral version was 6.39+/−9.14 degrees. The mean stem version was 9.23+/−8.57 degrees. With respect to achieving a target version of 15 degrees the mean absolute difference between native version and 15 degrees was 10.46+/−6.94 degrees and mean absolute difference between the stem version and 15 degrees was 8.37+/−6.03 degrees. This difference was statistically significant. 69% of patients were able to have their native femoral version corrected to a target of 15 degrees. Conclusions. Robotic guidance in THA was effective in correcting native femoral version towards a target of 15 degrees. This is can be achieved using both the anterior and posterior approach and is not affected by BMI

Unicondylar knee arthroplasty (UKA) is growing in popularity with an increase in utilisation. As a less invasive, bone preserving procedure suitable for knee osteoarthritic patients with intact cruciate ligaments and disease confined to one compartment of the knee joint. The long term survival of a UKA is dependent on many factors, including the accuracy of prosthesis implantation and soft tissue balance. Robotic assisted procedures are generally technically demanding, can increase the operation time and are associated with a learning curve. The learning curve for new technology is likely to be influenced by previous experience with similar technologies, the frequency of use and general experience performing the particular procedure. The purpose of this study was to determine the time to achievement of a steady state with regards to surgical time amongst surgeons using a novel hand held robotic device. This study examined consecutive UKA cases which used a robotic assistive device from five surgeons. The surgeons had each performed at least 15 surgeries each. Two of the surgeons had previous experience with another robotic assistive device for UKA. All of the surgeons had experience with conventional UKA. All of the surgeons have used navigation for other knee procedures within their hospital. The system uses image free navigation with infrared optical tracking with real time feedback. The handheld robotic assistive system for UKA is designed to enable precision of robotics in the hands of the surgeon. The number of surgeries required to reach ‘steady state’ surgical time was calculated as the point in which two consecutive cases were completed within the 95% confidence interval of the surgeon's ‘steady state’ time. The average surgical time (tracker placement to implant trial acceptance phase) from all surgeons across their first 15 cases was 56.8 minutes (surgical time range: 27–102 minutes). The average improvement was 46 minutes from slowest to quickest surgical times. The ‘cutting’ phase was reported as decreasing on average by 31 minutes. This clearly indicates the presence of a learning curve. The surgeons recorded a significant decrease in their surgical time where the most improvement was in the process of bone cutting (as opposed to landmark registration, condyle mapping and other preliminary or planning steps). There was a trend towards decreasing surgical time as case numbers increase for the group of five surgeons. On average it took 8 procedures (range 5–11) to reach a steady state surgical time. The average steady state surgical time was 50 minutes (range 37–55 minutes). In conclusion, the average operative time was comparable with clinical cases reported using other robotic assistive devices for UKA. All five surgeons using the novel handheld robotic-assisted orthopaedic system for UKA reported significant improvement in bone preparation and overall operative times within the first 15 cases performed, reaching a steady state in surgical times after a mean of 8 cases. Therefore, this novel handheld device has a similar learning curve to other devices on the market

Background. The Robotic Spinal Surgery System (RSSS) is a robot system designed for pedicle screw insertion containing image based navigation system, trajectory planning system and force state recognition system. The special force state recognition system can guarantee the safety during the operation. The RSSS is helpful in pedicle screw insertion surgery and it will be applied in clinic in the near future. In this study, we evaluated the accuracy and safety of RSSS in an animal experiment. Methods. Computer tomography (CT) scan data for two anesthetised experimental sheep was acquired using the C-arm and transferred to RSSS for pre-surgery screw trajectory planning. With the assist of RSSS, we inserted 8 and 4 screws into two sheep respectively. Operation time and blood loss during the surgery were recorded, and CT scan was repeated after surgery. Real screw position and trajectory acquired by the post-surgery CT scan and ideal trajectory planned by RSSS were compared to evaluate the accuracy and safety of RSSS. The result is shown as mean±SD. Results. We planted totally 12 screws into two sheep. The operation time for each sheep is 140min and 110min, and the blood loss is 100ml and 80 ml respectively. Compared with planned trajectory, the average deviation of the entry points in lateral and axial view are 1.07±0.56mm and 1.25±0.42mm and the mean screw deviation angles in later and axial view are 1.78±0.98°and 2.52±1.03°respectively. The RSSS successfully recognised the force stages and guaranteed the safety during the drilling process. There is no penetration in all 12 pedicles, and all the screws fell into group A according to the Gertzbein-Robbins classification. Conclusion. This animal study demonstrated the accuracy and safety of the RSSS, which also supported the potential application in clinic

Abstract

Combined acetabular and femoral anteversion (CA) of the hip following total hip arthroplasty (THA) is critical to the hip function and longevity of the components. However, no study has been reported on the accuracy in restoration of CA of the hip after operation using robotic assistance and conventional free-hand techniques. The purpose of this study was to evaluate if using robotic assistance in THA can better restore native CA than a free-hand technique. Twenty three unilateral THA patients participated in this study. Twelve of them underwent a robotic-arm assisted THA (RIO® Robotic Arm Interactive Orthopedic System, Stryker Mako., Fort Lauderdale, FL, USA) and eleven received a free-hand THA. Subject specific 3D models of both implanted and non-implanted hips were reconstructed using post-operative CT scans. The anteversion and inclination of the native acetabulum and implanted cup were measured and compared. To determine the differences of the femoral anteversion between sides, the non-implanted native femur was mirrored and aligned with the remaining femur of the implanted side using an iterative closest point algorithm. The angle between the native femoral neck axis and the prosthesis neck axis in transverse plane was measured as the change in femoral anteversion following THA. The sum of the changes of the acetabular and femoral anteversion was defined as the change of CA after THA. A Wilcoxon signed rank test was performed to test if the anteversion of the navigation and free-hand THAs were different from the contralateral native hips (α = 0.05). The acetabular anteversion were 22.0°±7.4°, 35.9°±6.5° and 32.6°±22.6° for the native hips, robotic assisted THAs and free-hand THAs, respectively, and the corresponding values of the acetabular inclinations were 52.0°±2.9°, 35.4°±4.4° and 43.1°±7.1°. The acetabular anteversion was increased by 12.2°±11.1° (p=0.005) and 12.5°±20.0° (p=0.102) for the robotic assisted and the free-hand THAs. The femoral anteversion was increased by 6.3°±10.5° (p=0.077) and 11.0°±13.4° (p=0.014) for the robotic assisted and free-hand THAs, respectively. The CA were significantly increased by 18.5°±11.7° (p<0.001) and 23.5°±26.5° (p=0.019) for the robotic assisted and the free-hand THAs. The changes of the CA of the free-hand THAs varied in a larger range than those of the robotic assisted THAs. This study is the first to evaluate the changes in acetabular and femoral anteversions of the hips after robotic assisted and free-hand THAs using the contralateral native hip as a control. The results demonstrate that both the navigation and free-hand THAs significantly increased the CA compared to the contralateral native hips, but the changes of the robotic assisted THAs (18.5°±11.7°) were smaller and varied less than those of the free-hand THAs (23.5°±26.5°). These data suggest that the robotic assisted THA can better restore the native hip CAs with higher repeatability than the free-hand technique. Further studies are needed to investigate the effects of the hip anteversion changes on the in-vivo function of the hip and the long-term outcomes in THA patients

The purposes of this study were to report the accuracy of stem anteversion for Exeter cemented stems with the Mako hip enhanced mode and to compare it to Accolade cementless stems.

We reviewed the data of 25 hips in 20 patients who underwent THA through the posterior approach with Exeter stems and 25 hips in 19 patients with Accolade stems were matched for age, gender, height, weight, disease, and approaches. There was no difference in the target stem anteversion (20°–30°) between the groups. Two weeks after surgery, CT images were taken to measure stem anteversion.

The difference in stem anteversion between the plan and the postoperative CT measurements was 1.2° ± 3.8° (SD) on average with cemented stems and 4.2° ± 4.2° with cementless stems, respectively (P <0.05). The difference in stem anteversion between the intraoperative measurements and the postoperative CT measurements was 0.75° ± 1.8° with Exeter stems and 2.2° ± 2.3° with Accolade stems, respectively (P <0.05).

This study demonstrated a high precision of anteversion for Exeter cemented stems with the Mako enhanced mode and its clinical accuracy was better with the cemented stems than that with the cementless stems. Although intraoperative stem anteversion measurements with the Mako system were more accurate with the cemented stems than that with the cementless stem, the difference was about 1° and the accuracy of intra-operative anteversion measurements was quite high even with the cementless stems. The smaller difference in stem anteversion between the plan and postoperative measurements with the cemented stems suggested that stem anteversion control was easier with cemented stems under the Mako enhanced mode than that with cementless stems.

Intraoperative stem anteversion measurement with Mako total hip enhanced mode was accurate and it was useful in controlling cemented stem anteversion to the target angle.

While THA is regarded as one of the most successful surgeries in medicine, recent studies have revealed that ideal acetabular cup implantation is achieved as little as 50% of the time. Malalignment of the acetabular component in THA may result in dislocation, reduced range of motion, or accelerated wear. Recently, robotic-assisted surgery has been introduced to reduce the errors in component placement. The purpose of this study is to longitudinally assess the accuracy of cup placement of a single surgeon at three points in time: directly following a total joint fellowship, after 10 years of experience with manual instrumentation, and directly after adopting robotic technology. Three hundred patients received THA at a single center by a single surgeon representing three series of 100 consecutive patients in each series. The first series A included the surgeon's first 100 THA patients following graduation from joint fellowship (2/2000–5/2002). The second series B included the surgeon's last 100 THA patients before adopting robotic technology (12/2010–1/2012) and the final series C included the surgeon's first 100 THA patients using robotic assistance (4/2012–4/2013). The post-operative abduction and version of the cup was measured using PACS imaging software from the AP and cross-table lateral radiographs. Abduction was measured using a transverse line at the level of the teardrop and the lateral opening angle of the cup relative to this reference line. Anteversion was measured using the ischial method described by Schmalzreid on the crosstable lateral view and accounts for pelvic flexion. The average inclination for the groups A, B, and C was 48.6 ± 7.6°, 37.4 ± 6.2°, and 39.6 ± 47.6°, respectively and for anteversion was 29.3 ± 10.3°, 26.6 ± 8.4°, and 23.6 ± 5.7°, respectively. The cup placement in the original series A was within the Lewinnek safe zone only 31% of the time. This increased to 45% in series B and up to 74% in series C (p < 0.05). With the robotic series C, the three-dimensional pre-operative plan was obtained from the software. The average error (final placement–plan) was −0.7 ± 2.1° for inclination and 1.1 ± 2.0° for version. 93% of the inclination measurements and 94% of the version measurements were within 5° of the plan and 100% of both measurements were within 10° of the plan. Of note, 8% of the robotic cases were actually planned outside of the Lewinnek safe zone to accommodate for patient deformity and optimize correction to achieve the targeted combined anteversion of the acetabular and femoral components. Robotic assistance in THA leads to significantly more precise acetabular cup placement. As measured by the Lewinnek safe zone, 10 years of experience resulted in a 45% increase in precision, while adding robotic assistance resulted in a 139% increase in precision compared to the surgeon's initial performance. With greater knowledge of ideal acetabular cup position, highly accurate techniques may allow surgeons to decrease the risk of dislocation, promote durability and improve the ability to restore appropriate leg length and offset

Abstract

Total joint arthroplasty (TJA) is one of the commonest and most successful orthopaedic procedures used for the management of end-stage arthritis. With the recent introduction of robotic-assisted joint replacement, Computed tomography (CT) has become part of required pre-operative planning.

The aim of this study is to quantify and characterise incidental CT findings, their clinical significance, and their effect on the planned joint arthroplasty.

All consecutive patients undergoing an elective TJA (total joint arthroplasty; hip or knee) were retrospectively identified, over a 4-year period (December 2019 and November 2023). Data documented and analysed included patient demographics, type of joint arthroplasty, CT findings, their clinical significance, as well as potential delays to the planned arthroplasty because of these findings and subsequent further investigation.

A total of 987 patients (female: 514 patients (52.1%)) undergoing TJA were identified (THA: 444 patients (45.0%); TKA: 400 patients (40.5%); UKA: 143 patients (14.5%)). Incidental findings within imaged areas were identified in 227 patients (23.0%). Of these findings, 74 (7.5%) were significant, requiring further investigation or management, 40 (4.1%) of which represented potential malignancy and 4 (0.4%) resulting in a new cancer diagnosis. A single patient was found to have an aneurysm requiring urgent vascular intervention. Surgery was delayed for further investigation in 4 patients (0.4%). Significant findings were more frequent in THA patients (THA: 43 (9.7%) TKA/UKA: 31 (5.7%)

Within our cohort, 74 (7.5%) patients had significant incidental findings that required further investigations or management, with 4 (0.4%) having a previously undiagnosed malignancy. We strongly advocate that all robotic arthroplasty planning CTs are reviewed and reported by a specialist, to avoid missing undiagnosed malignancies and other significant diagnoses.

Introduction. Severe angular deformities in total knee arthroplasty require specific attention to bone resections and soft tissue balancing. This can add technical complexity and time, with some authors reporting an increase of approximately 20 minutes in mean surgery time when managing large deformities with conventional instrumentation [1]. We evaluate the utility of computer-navigation with imageless BoneMorphing® and Apex Robotic Technology, or A.R.T.® for managing large deformities in TKA. BoneMorphing® allows for real-time visualization of virtual bone resection contours, limb alignment and soft-tissue balance during TKA. A.R.T. permits accurate cutting and recutting of the distal femur in 1 mm increments. We asked what effects do severe pre-operative deformities have on post-operative alignment and surgery time in comparison to knees with only mild deformities when using this system. Methods. This was a retrospective cohort study of 128 consecutive A.R.T. TKA's performed by a single surgeon (mean age: 71 y/o [range 53–93], BMI: 31.1 [20–44.3], 48 males). Patients were stratified into three groups according to their pre-operative coronal plane deformity: Neutral or mild deformity <10° (baseline group); Severe varus ≥10°; and Severe valgus ≥10°; and according to the degree of flexion contracture: Neutral or mild flexion from −5° hyperextension to 10° flexion (baseline group); Hyperextension ≤−5°, and Severe flexion ≥10°. The degree of deformity and final postoperative alignment achieved was measured using computer navigation in all patients and analyzed using multivariate regression. The APEX CR/Ultra Knee System (OMNIlife Science, Inc.) was used in all cases. Results. Pre-operative coronal alignment ranged from 27° varus to 22° valgus (figure 1). Postoperative alignment across all patients ranged from 2° valgus to 3.5° varus (figure 2), and from 4° flexion to −4° hyperextension. Effect of deformity on alignment accuracy. Mean post-operative alignment was 1.4° varus in the control group, 0.4° varus in the severe valgus group (p=0.004), and 1.8° varus in the severe varus group (p=0.111). Preoperative flexion, obesity, and gender had no significant effect on alignment accuracy or final extension. Tourniquet time. Mean tourniquet time for the control group was 48.8 minutes [95% CI: 45.3–52.4] (figure 3). Severe varus knees took 4.8 min longer (p=0.006), while valgus knees took 2.9 min longer (p=0.260). Flexion contractures ≥10° and ≥15° increased tourniquet time by 3.8 min (p=0.152) and 10 min (p=0.033), respectively. Tourniquet time was slightly longer in obese patients by 3.2 min (p = 0.048) and was 6.3 min shorter for females than males (p<0.001). Conclusions. We have shown that in one surgeon's hands severe coronal deformities and flexion contractures can be consistently corrected to within 3–4° of neutral when using A.R.T. This is achieved by assessing the pre-resection kinematics, formulating a virtual plan, and executing and validating in real time that plan's execution. The additional time required for managing these more difficult cases using this technology was typically less than 5 minutes, which demonstrates the effectiveness of real-time navigation and robotics for TKA

Introduction:. UKA allows replacement of a single compartment in patients who have isolated osteoarthritis. However, limited visualization of the surgical site and lack of patient-specific planning provides challenges in ensuring accurate alignment and placement of the prostheses. Robotic technology provides three-dimensional pre-op planning, intra-operative ligament balancing and haptic guidance of bone preparation to mitigate the risks inherent with current manual instrumentation. The aim of this study is to examine the clinical outcomes of a large series of robot-assisted UKA patients. Methods:. The results of 500 consecutive medial UKAs performed by a single surgeon with the use of a metal backed, cemented prosthesis installed with haptic robotic guidance. The average age of the patients at the time of the index procedure was 71.1 years (range was 40 to 93 years). The average height was 68 inches (range 58″–77″) and the average weight was 192.0 pounds (range 104–339 pounds). There were 309 males and 191 females. The follow-up ranges from 2 weeks to 44 months. Results:. Surgical Technique: The technique evolved from a one night stay with a tourniquet and a retinacular “T'd” arthrotomy, to a same day surgical procedure with a 2.5–3 inch straight medial arthrotomy that is muscle sparing and tourniquet free allowing all patients to go home the same day with only 2–3 weeks of formal physical therapy post op, less pain medication and a quicker return to their preoperative range of motion. Clinical Outcomes: All patients increased their ROM by 3–6 months postop. The return to preoperative ROM was seen by 6 weeks with an increased ROM of 5–10 degrees by 1 year. 6 out of 500 patients were converted to a TKA (1.2%). Two for deep infection (one had severe venous stasis disease preop), Three for medial pain despite stable, well aligned implants, and one who developed pain at around 6 weeks that had a large scar band that formed across the top of the tibial poly causing pain with weight bearing. Conclusion:. This evolved surgical technique along with the use of the sophisticated, patient-specific preoperative and intraoperative planning software combined with haptically guided bone resection allowed most patients, regardless of age, to have their procedure performed as an outpatient. This new technique can provide significant savings to the healthcare system in terms of costs of hospital days, costs of rehabilitation, costs in pain medication and quality of life in the acute post operative period with no increased risk of failure, loosening, malalignment, DVT, PE, infection, return to the OR, readmissions, or manipulation

The purposes of this study were to evaluate the accuracy and feasibility of a robotic preparation for acetabular metal augments in patients with developmental dysplasia of the hip (DDH). Mako robotic arm reaming was used in 7 DDH to prepare the bony cavities for both Trident PSL cups and Tritanium acetabular wedge augments in six hips with Crowe 2 or 3 DDH. In CT-based planning, a properly sized cup was placed in the original acetabulum, and the same sized cup was also placed to fit the superolateral acetabular defect. The coordinates of the planned positions of cup and augment were recorded to manage the robotic arm reaming. After registration of the patient's pelvis, robotic reaming was performed first for the augment, then, for the cup by changing the target position of reaming as planned. The accuracy of the cup and augment placement was assessed on postoperative CT. To evaluate the feasibility of the robotic procedure, the OR time and blood loss were compared with those of 13 patients who received the same cup and augment systems with a conventional technique. All procedures were done without fracture or fixation failure. There were no differences in OR time or blood loss between the two procedures. Postoperative CT measurements of the distance between the cup center and the augment sphere center showed less than 2mm difference from the Mako preoperative planning.

Although a longer time of follow up evaluation is mandatory, our robotic acetabular augment preparation technique is accurate and feasible.

Robotic assisted spine surgery was a breakthrough in the evolution of spinal surgery, gradually gaining its place as an alternative technique for conventional spinal procedures. As the general population's life expectancy increased so does the incidence of spinal pathology and with it emerged an urging need for a safer and more accurate means of treatment. In our institute we apply the “Spine Assist” platform for a variety of spinal procedures as Vertebroplasties, biopsies, Pedicular screws insertion and an inter-vertebral fusion – GOLIF procedures. This study is designed to analyze the learning curve of each procedure, regarding the amount of fluoro images (FI) taken, fluoro exposure (FE) time and net operation time. All spinal procedures using the “Spine Assist” platform were included in this study; all took place from 2006 until September 2010. Exclusion criteria were procedures with failed pre-op registration, and robotic assisted procedures that were converted to conventional fluoroscopic assisted during the operation. Every single surgery of all types of procedures was analyzed regarding the amount of FI taken, FE time and net operation time. Pedicular screws insertion was grouped into sets of four, where the same parameters were evaluated. Altogether we preformed 106 robotic assisted Vertebroplasty procedures. During this period a distinct learning curve was observed and analyzed. For the first ten Vertebroplasties an average of 12 FI were taken with a net operation time of 53.6 min per procedure. Analyzing the first 40 procedures has shown less FI per procedure (5 FI) and a net operation time of 48.6 min/procedure. Data drawn from the 51 following Vertebroplasties has set the standards of 4 FI with a net operation time of 25.6 min/procedure. Two Vertebroplasty procedures were not completed due to failure of software registration. Pedicular screws are a mean for stabilization of vertebral motion units. During a six years period 706 screws were inserted, out of whom 98 were inserted using percutaneous technique. Comparing the insertion of a set of 4 screws we found a significant improvement regarding the number of FI, FE time and the net operation time between the first ten procedures and the rest with a mean of 20 FI /4 FI and net screw insertion time of 82 min/ 25 min respectively. We found no difference in the parameters comparing percutaneous Vs open Pedicular screws insertion. The mean accuracy of all procedures was 0.3 mm compared to the pre planned screw trajectory. No false route was detected in any of the 506 procedures. This robotic assisted technique is a new and safe approach aiming to shorten the duration of the procedure, thus reducing the patient and surgeon exposure to radiogenic dose. The essence of robotic assisted surgery is a pre planned needle/screw trajectory aiming to reduce the possible intra-operative complication, inaccuracies and possible mishaps emerging during “free hand” procedures. Gaining more experience using the spine assist platform, as shown in this detailed learning curve, enabled us to leverage the platform for ultra-accurate procedures as the percutaneous intervertebral fusion – GOLIF, Vertebroplasty for burst fractures etc

Aims

To perform an incremental cost-utility analysis and assess the impact of differential costs and case volume on the cost-effectiveness of robotic arm-assisted unicompartmental knee arthroplasty (rUKA) compared to manual (mUKA).

Unicompartmental knee arthroplasty (UKA) has a higher risk of revision than total knee arthroplasty, particularly for low volume surgeons. The recent introduction of robotic-arm assisted systems has allowed for increased accuracy, however new systems typically have learning curves. The objective of this study was to determine the learning curve of a robotic-arm assisted system for UKA.

Methods A total of 152 consecutive robotic-arm assisted primary medial UKA were performed by five surgeons between 2017 and 2021. Operative times, implant positioning, reoperations and patient-reported outcome measures (PROMS; Oxford Knee Score, EuroQol-5D, and Forgotten Joint Score) were recorded.

There was a learning curve of 11 cases with the system that was associated with increased operative time (13 minutes, p<0.01) and improved insert sizing over time (p=0.03). There was no difference in implant survival (98.2%) between learning and proficiency phases (p = 0.15), and no difference in survivorship between ‘high’ and ‘low’ usage surgeons (p = 0.23) at 36 months. There were no differences in PROMS related to the learning curve. This suggested that the learning curve did not lead to early adverse effects in this patient cohort.

The introduction of a robotic-arm assisted UKA system led to learning curves for operative time and implant sizing, but there was no effect on patient outcomes at early follow- up. The short learning curve was independent of UKA usage and indicated that robotic-arm assisted UKA may be particularly useful for low-usage surgeons.

Abstract

Introduction

Robot systems have been successfully introduced to improve the accuracy and reduce severe iatrogenic soft tissue damage in knee arthroplasty. Unfortunately to perform complete a complete bone cut, the cutting tool has to slightly pass the edge of the bone. In the posterior zones were retractor protection is impossible this will lead to contact between the cutting tool and the soft tissue envelope. Therefore, complete soft tissue preservation cannot be guaranteed with the current commercial systems.

Aims

The aim was to assess whether robotic-assisted total knee arthroplasty (rTKA) had greater knee-specific outcomes, improved fulfilment of expectations, health-related quality of life (HRQoL), and patient satisfaction when compared with manual TKA (mTKA).

Component malposition in total hip arthroplasty (THA) contributes to wear, dislocation, and leg length discrepancy (LLD). Robotic assisted total hip arthroplasty (rTHA) utilises computer-assisted haptically guided bone preparation and implant insertion to improve accuracy. The goal of this study is to compare accuracy and clinical outcome with manual THA (mTHA) and rTHA at minimum 1 year follow-up interval. Consecutive primary THA performed by one fellowship trained surgeon included: the first 100 mTHAs in his clinical practice (Group1- year 2000), the last 100 mTHAs before rTHA use (Group2- year 2010), and the first 100 rTHA (Group3- year 2011). All THAs utilised cementless implants, cross-linked polyethylene, and a posterior approach. Comparisons included age, sex, diagnosis, implant head size, blood loss (EBL), operative time, LLD, early dislocation and infection. Acetabular abduction (AAB), anteversion (AAV), and LLD were measured using validated software (Martell Hip Analysis Suite). The Lewinnek safe zone defined accuracy (AAB- 30°-50°, AAV- 5°-25°). Statistical analysis included ANOVA, Chi squared, and Fisher tests. Power analysis demonstrated adequate sample sizes. No differences were noted regarding group demographics. Average operative times varied: Group 1, 2, and 3- (160, 129, and 143 minutes, respectively). No deep infections occurred in any group. LLD greater than 1.5 cm varied: Groups 1, 2, and 3 (9%, 1%, 1%, respectively). Dislocation rates varied: Groups 1, 2, and 3- (5%, 3%, and 0%, respectively). EBL was less with rTHA than mTHA (Groups 1, 2, 3: 533cc, 437cc, 357cc, respectively). Average implant head size increased comparing Groups 1, 2, and 3 (31mm, 34.6mm, and 35.2mm, respectively). AAB accuracy varied: Groups 1, 2, and 3 (66%, 91%, and 98%, respectively). AAB greater than 55 degrees varied: Groups 1, 2, and 3 (15%, 1%, and 0%, respectively). There was a 3% fractured acetabular liner rate in Group 1, all cases occurred with AAB > 55 degrees, and AAB greater than 55 degrees correlated with increased acetabular liner fracture rate (20% vs. 0%, P < 0.05). No cases of fractured acetabular liners occurred in Group 2 or 3. rTHA improved AAV accuracy compared with mTHA (Group 2- 48%, Group 3- 75%; p<0.0001). Improved acetabular component accuracy with rTHA correlated with lower dislocation rates compared with mTHA (p<0.001). Total hip arthroplasty performed with traditional manual techniques has demonstrated excellent clinical outcomes in the majority of patients with many THA designs if components are placed accurately. Limitations in mTHA remain that alter results if accurate component placement is not achieved. In our study, clinical experience over 10 years improved AAB accuracy with mTHA, but AAV remained problematic. rTHA improved AAB and AAV accuracy compared with mTHA and demonstrated reduced early dislocation rates, improved rate of LLD, and reduced acetabular liner fracture risk compared with mTHA (p<0.05). Average rTHA operative times were 14 minutes longer than mTHA (Group 2), but this was not associated with increased EBL or infection rates. Further study is needed to evaluate whether the short term clinical and radiographic advantages noted with rTHA compared with mTHA will be maintained at longer follow up intervals

Background: Vertebral compression fractures can affect both sexes and constitute a major health care problem, due to negative impact on the patient’s function, quality of life and the costs to the health care system. Patients can be treated conservatively or by conventional vertebroplasty. Conventional vertebroplasty imposes technical challenges with possible complications including cement extravasations, nerve root compression, breaching the walls of the pedicle by the osteoplasty needle and prolonged fluoroscopic radiation exposure of the surgeon and the medical team at large. Methods: Retrospective comparative study of 20 cases of thoraco-lumbar vertebral compression fracture, treated with robotic assisted vertebroplasty (research group) versus 30 cases of fractures treated by conventional fluoroscopic vertebroplasty (compared group). All patients were diagnosed as suffering from acute vertebral compression fractures (up to 3 weeks from the traumatic event) and were scored 7 and above in the VAS. Results: The mean overall operation time of the fluoroscopic assisted vertebroplasty was 35 minutes compared to a mean operation time of 45 minutes at the robotic assisted vertebroplasty. There was a significant difference in the fluoroscopic time and subsequent exposure time to radiation between the groups: in the research group we used only an average of 3 seconds of fluoroscopic exposure (an average of 5 fluoroscopic images) compared to an average of 7 seconds of exposure (an average of 12 fluoroscopic images). No difference was found between the groups in regard with overall admission time or with the time between the operation and physiotherapy. Conclusions: Robotic assisted vertebroplasty is a new and safe approach aiming to shorten the duration of fluoroscopic exposure and radiogenic dose of the patient and surgeon. This novel procedure, promotes better accuracy with regard to the cement injected thus reducing the potential complication of the operation