Aims

Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA.

Aims

The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

Aims

Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model.

Aims

It is unknown whether gap laxities measured in robotic arm-assisted total knee arthroplasty (TKA) correlate to load sensor measurements. The aim of this study was to determine whether symmetry of the maximum medial and lateral gaps in extension and flexion was predictive of knee balance in extension and flexion respectively using different maximum thresholds of intercompartmental load difference (ICLD) to define balance.

Aims. In-hospital length of stay (LOS) and discharge dispositions following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, it is imperative to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge dispositions following robotic arm-assisted total knee arthroplasty (RO TKA) and unicompartmental arthroplasty (RO UKA) versus conventional technique (CO TKA and UKA). Methods. This large-scale, single-institution study included patients of any age undergoing primary TKA (n = 1,375) or UKA (n = 337) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for post anaesthesia care unit (PACU) admission, anaesthesia type, readmission within 30 days, and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. Results. The median LOS in the RO TKA group was 76 hours (interquartile range (IQR) 54 to 104) versus 82.5 (IQR 58 to 127) in the CO TKA group (p < 0.001) and 54 hours (IQR 34 to 77) in the RO UKA versus 58 (IQR 35 to 81) in the CO UKA (p = 0.031). Discharge dispositions were comparable between the two groups. A higher percentage of patients undergoing CO TKA required PACU admission (8% vs 5.2%; p = 0.040). Conclusion. Our study showed that robotic arm assistance was associated with a shorter LOS in patients undergoing primary UKA and TKA, and no difference in the discharge destinations. Our results suggest that robotic arm assistance could be advantageous in partly addressing the upsurge of knee arthroplasty procedures and the concomitant healthcare burden; however, this needs to be corroborated by long-term cost-effectiveness analyses and data from randomized controlled studies. Cite this article: Bone Jt Open 2023;4(10):791–800

The February 2023 Hip & Pelvis Roundup. 360. looks at: Total hip arthroplasty or internal fixation for hip fracture?; Significant deterioration in quality of life and increased frailty in patients waiting more than six months for total hip or knee arthroplasty: a cross-sectional multicentre study; Long-term cognitive trajectory after total joint arthroplasty; Costal cartilage grafting for a large osteochondral lesion of the femoral head; Foley catheters not a problem in the short term; Revision hips still a mortality burden?; How to position implants with a robotic arm; Uncemented stems in hip fracture?

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

Introduction. Robotic-assisted hip arthroplasty helps acetabular preparation and implantation with the assistance of a robotic arm. A computed tomography (CT)-based navigation system is also helpful for acetabular preparation and implantation, however, there is no report to compare these methods. The purpose of this study is to compare the acetabular cup position between the assistance of the robotic arm and the CT-based navigation system in total hip arthroplasty for patients with osteoarthritis secondary to developmental dysplasia of the hip. Methods. We studied 31 hips of 28 patients who underwent the robotic-assisted hip arthroplasty (MAKO group) between August 2018 and March 2019 and 119 hips of 112 patients who received THA under CT-based navigation (CT-navi group) between September 2015 and November 2018. The preoperative diagnosis of all patients was osteoarthritis secondary to developmental dysplasia of the hip. They received the same cementless cup (Trident, Stryker). Robotic-assisted hip arthroplasty were performed by four surgeons while THA under CT-based navigation were performed by single senior surgeon. Target angle was 40 degree of radiological cup inclination (RI) and 15 degree of radiological cup anteversion (RA) in all patients. Propensity score matching was used to match the patients by gender, age, weight, height, BMI, and surgical approach in the two groups and 30 patients in each group were included in this study. Postoperative cup position was assessed using postoperative anterior-posterior pelvic radiograph by the Lewinnek's methods. The differences between target and postoperative cup position were investigated. Results. The acetabular cup position of all cases in both Mako and CT-navi group within Lewinnek's safe zone (RI: 40±10 degree; RA: 15±10 degree) in group were within this zone. Three was no significant difference of RI between Mako and CT-navi group (40.0 ± 2.1 degree vs 39.7± 3.6 degree). RA was 15.0 ± 1.2 degree and 17.0 ± 1.9 degree in MAKO group and in CT-navi group, respectively, with significant difference (p<0.001). The differences of RA between target and postoperative angle were smaller in MAKO group than CT-navi group (0.60± 1.05 degree vs 2.34± 1.40 degree, p<0.001). The difference or RI in MAKO group was smaller than in CT-navi, however, there was no significance between them (1.67± 1.27 degree vs 2.39± 2.68 degree, p=0.197). Conclusions. Both the assistance of the robotic arm and the CT-based navigation system were helpful to achieve the acetabular cup implantation, however, MAKO system achieved more accurate acetabular cup implantation than CT-based navigation system in total hip arthroplasty for the patients with OA secondary to DDH. Longer follow-up is necessary to investigate the clinical outcome

Introduction. Recent technological advancements have led to the introduction of robotic-assisted total knee arthroplasty to improve the accuracy and precision of bony resections and implant position. However, the in vivo accuracy is not widely reported. The primary objective of this study is to determine the accuracy and precision of a cut block positioning robotic arm. Method. Seventy-seven patients underwent total knee arthroplasty with various workflows and alignment targets by three arthroplasty-trained surgeons with previous experience using the ROSA® Knee System. Accuracy and precision were determined by measuring the difference between various workflow time points, including the final pre-operative plan, validated resection angle, and post-operative radiographs. The mean difference between the measurements determined accuracy, and the standard deviation represented precision. Results. The accuracy and precision for all angles comparing the final planned resection and validated resection angles was 0.90° ± 0.76°. The proportion within 3° ranged from 97.9% to 100%. The accuracy and precision for all angles comparing the final intra- operative plan and post-operative radiographs was 1.95 ± 1.48°. The proportion of patients within 3° was 93.2%, 95.3%, 96.6%, and 71.4% for the distal femur, proximal tibia, femoral flexion, and tibial slope angles when the final intra-operative plan was compared to post-operative radiographs. No patients had a postoperative complication requiring revision at the final follow-up. Conclusions. This study demonstrates that the ROSA Knee System has accurate and precise coronal plane resections with few outliers. However, the tibial slope demonstrated decreased accuracy and precision were measured on post-operative short-leg lateral radiographs with this platform

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. Adult reconstructive orthopedic surgery in the United States is facing an imminent logjam due to the increasing divergence of the demand for services and the ability for the community to supply those services. In combination with several other factors, a perfect storm is brewing that may leave the system overtaxed and the patient population suffering from either a lack of treatment, or treatment by less qualified providers. A key component to improving the overall efficiency of surgical care is to introduce enabling technologies that can effectively increase the throughput while simultaneously improving the quality of care. One such enabling technology that has proven itself in many industries is robotics, which has recently been introduced in surgery with even more recent applications in orthopedic surgery. A surgeon interactive robotic arm has been developed for partial knee arthroplasty (PKA) and total hip arthroplasty (THA). This study aims to analyse the efficiency of a new robotic technology for use in orthopaedic surgery. METHODS. 18 robotic arm assisted PKA's across 10 sites were recorded to accurately capture the timeline elemental tasks throughout the procedure. Two camera angles were set up to capture both surgical staff group dynamics and individual procedural steps. 17 tasks were identified and measured from video data. (Fig 1) The robotic arm specific tasks were analyzed for correlation to total surgical time (measured as first incision to last suture). The tasks for the surgeons with the shortest and longest total times were compared directly to determine areas of opportunity. RESULTS. Average total time across 18 surgeries was 55 ± 19 min (range: 30–98 min). There was no correlation between bone registration time and total time (p=0.271) and no correlation between femoral burring time and total time (p=0.230). Per task time comparison of the two surgeons exhibited an average time variation of 3.5 min per task (range: 0.7–8.4 min) (Fig 2). The robotic elements of the procedure exhibited an average time variation of 3.3 min per task while the non robotic elements of the procedure (boxed) exhibited an average time variation of 3.8 min per task. CONCLUSION. Our preliminary results indicate that introducing robotic technology in to the OR does not directly lead to an increase in total surgical time. On average, non robotic specific elements of the procedure exhibited a larger opportunity for efficiency gain. This is likely due to the fact that a large population of surgeon users are not only new to the robotic technology, but new to PKA. Further video collection and analysis will lead to an efficiency benchmarking program that aims to establish methods for best practices in achieving efficiency throughout a robotic arm assisted PKA procedure

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

Abstract. Objectives. Dual mobility (DM) hip implants whereby the polyethylene liner is “free-floating” are being used increasingly clinically. The motion of the liner is not well understood and this may provide insight into failure mechanisms; however, there are no published methods on tracking liner motion while testing under clinically relevant conditions. The aim was to develop and evaluate a bespoke inertial tracking system for DM implants that could operate submerged in lubricant without line-of-sight and provide 3D orientation information. Methods. Trackers (n=5) adhered to DM liners were evaluated using a robotic arm and a six-degree of freedom anatomical hip simulator. Before each set of testing the onboard sensor suites were calibrated to account for steady-state and non-linearity errors. The trackers were subjected to ranges of motion from ±5° to ±25° and cycle frequencies from 0.35Hz to 1.25Hz and the outputs used to find the absolute error at the peak angle for each principle axis. In total each tracker was evaluated for ten unique motion profiles with each sequence lasting 60 cycles. Results. Across all test conditions the angular error was consistently less than 1.1 ± 1.8° (mean ± SD) per principle axis with no relationship found between range of motion or cycle frequency and measurement error. Rotations about the trackers X and Y axes produced more repeatable results with a maximum spread of 5.5°, where as rotations about Z spread by up to 10.1°. Conclusions. The results of this study show that a system for monitoring DM liner motion without line of sight is possible, going forward this will be used to determine the effects of different loading and kinematic conditions on liner motions in a hip simulator

INTRODUCTION. Total hip arthroplasty (THA) is regarded as one of the most successful surgeries in medicine. However, recent studies have revealed that ideal acetabular cup implantation is achieved less frequently than previously thought, as little as 50% of the time. It is well known that malalignment of the acetabular component in THA may result in dislocation, reduced range of motion, or accelerated wear. This study reports accuracy of a tactile robotic arm system to ream the acetabulum and impact an acetabulur cup compared to manual instrumentation. METHODS. 12 fresh frozen cadaveric acetabulae were pre-operatively CT scanned and 3D templating was used to plan the center of rotation, and anteversion and inclination of the cup. Each specimen received THA, six prepared manually and six prepared with robotic arm guidance. Tactile, visual, and auditory feedback was provided through robotic guidance as well as navigated guided reaming and cup impaction. The robotic guidance constrained orientation of instruments thus constraining anteversion, inclination, and center of rotation for reaming, trialing, and final cup impaction. Post-operative CT scans were taken of each specimen to determine final cup placement for comparison to the pre-operative plans. RESULTS. In all cases, robotic arm guidance resulted in ±4° of anteversion and ±5° of inclination each relative to the pre-operative plan. Absolute RMS errors were 2.16 ± 1.35° for anteversion and 1.91 ± 1.55° for inclination. Cup placement with robotic guidance was significantly more accurate and precise than placement with manual instruments. With manual instrumentation the errors were, on average, 4.0 times higher in anteversion and 5.9 times higher in inclination compared to robotic instrumentation. CONCLUSION. This tactile robotic system substantially improved the accuracy of acetabular reaming and placement of the final cup compared to traditional manual techniques. 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. Tactile robotics has proven to be safe and effective in both knee and hip surgery and provides the potential to redefine the “instrument set” used for orthopedic procedures

Introduction. We report 10-year clinical outcomes of a prospective randomised controlled study on uni-compartmental knee arthroplasty using an active constraint robot. Measuring the clinical impact of CAOS systems has generally been based around surrogate radiological measures with currently few long-term functional follow-up studies reported. We present 10 year clinical follow up results of robotic vs conventional surgery in UKA. Material and methods. The initial study took place in 2004 and included 28 patients, 13 in the robotic arm and 15 in the conventional arm. All patients underwent medial compartment UKA using the ‘OXFORD’ mobile bearing knee system. Clinical outcome at 10 years was scored using the WOMAC scoring system. Results. 13 patients were initially included in the robotic arm, of these one was revised following trauma and a further two patient died leaving at total of 10 with an average age of 80 years. In the control arm, out of a total of 15 patients, 3 were revised to a total knee replacement due to pain, 1 has died and 1 lost to follow-up. Their mean age is 81. A total of 19 patients were included (conventional n=9, robotic n=10) in this follow up study. The WOMAC scores for the robotic group were lower - (p<0.05). Discussion. There is a paucity of data on 10 year outcome of computer assisted UKA and whilst most studies show no clinical benefit, our study suggests a better outcome, however our numbers now are small (n=19). In our original study 1 the primary outcome measure, tibiofemoral alignment in the coronal plane was within 2 degrees of the planned position in the robotic group whilst in the conventional group only 6 of the 15 knees achieved this level of accuracy - Fig 1. The primary hypothesis was that the use of an active constraint robot improved prosthetic position. This accuracy continues to be associated with improved functional outcome. Three revisions were performed prior to this period and were considered technical failures and have been excluded from this analysis

INTRODUCTION. Acetabular cup malpositioning has been implicated in instability and wear-related complications after total hip arthroplasty. Although computer navigation and robotic assistance have been shown to improve the precision of implant placement, most surgeons use mechanical and visual guides to place acetabular components. Authors have shown that, when using a bean bag positioner, mechanical guides are misleading as they are unable to account for the variability in pelvic orientation during positioning and surgery. However, more rigid patient positioning devices may allow for more accurate free hand cup placement. To our knowledge, no study has assessed the ability of rigid devices to afford surgeons with ideal pelvic positioning throughout surgery. The purpose of this study is to utilize robotic-arm assisted computer navigation to assess the reliability of pelvic position in total hip arthroplasty performed on patients positioned with rigid positioning devices. METHODS. 100 hips (94 patients) prospectively underwent total hip Makoplasty in the lateral decubitus position from the posterior approach; 77 stabilized by universal lateral positioner, and 23 by peg board. After dislocation but prior to reaming, one fellowship trained arthroplasty surgeon manually placed the robotic arm parallel to both the longitudinal axis of the patient and the horizontal surface of the operating table, which, if the pelvis were oriented perfectly, would represent 0 degrees of anteversion and 0 degrees of inclination. The CT-templated computer software then generated true values of this perceived zero degrees of anteversion and inclination based on the position of the robot arm registered to a preoperative pelvic CT. Therefore, variations in pelvic positioning are represented by these robotic navigation generated values. To assure the accuracy of robotic measurements, cup anteversion and inclination at times of impaction were recorded and compared to those calculated via the trigonometric ellipse method of Lewinnek on standardized 3 months postoperative X-rays. RESULTS. Mean alteration in anteversion and inclination values were 1.7 degrees (absolute value 5.3 degrees, range −20 – 20 degrees) and 1.6 degrees (absolute value 2.6 degrees, range −8 – 10 degrees) respectively. 22% of anteversion values were altered by >10 degrees; 41% by > 5 degrees. There was no difference between positioners (p=0.36) and regression analysis revealed that anteversion differences were correlated with BMI (p=0.02). Robotic navigation acetabular cup anteversion (mean 21.8 degrees) was not different from postoperative X-ray anteversion (mean 21.9 degrees)(p=0.50), nor was robotic navigation acetabular cup inclination (mean 40.6 degrees) different from postoperative X-ray inclination (mean 40.5 degrees)(p=0.34). DISCUSSION AND CONCLUSION. Rigid pelvic positioning devices present 5 to 20 degrees of variability in acetabular cup orientation, particularly with regards to anteversion. Compounding this with 20 degree safe zones and prior author demonstrations that human error is prone to 10 degrees of anteversion inaccuracy in a fixed pelvis model, there is a clear need to pay particular attention to anatomic landmarks or computer assisted techniques to assure accurate acetabular cup positioning. Patient positioning by itself should not be trusted

This paper illustrates the concept of a versatile surgical assistance system which combines an optical navigation system and a robotic arm. The integrated system offers precise positioning and guiding of surgical instruments according to pre-operative planning. A unique feature results from its capability to track small motions of the patient in real time, eliminating the need to rigidly fix the anatomical structure to be operated. The modular system architecture facilitates the adaptation of a common basic hardware platform to various surgical applications by adding associated software modules as well as appropriate surgical tools mounted to the robotic arm. The arm can be regarded as a controlled machine actuator of a navigation system. Its operation is mainly controlled by interactive operating modes which are based on a versatile haptic interface. The system supports the surgeon in those parts of a procedure where human skills are limited, but always lets him take full control, for example by directly grasping and moving the arm at its wrist if he wants to push the arm aside

Fluid film lubricating ability of a total hip prosthesis depends on the profile accuracies including surface-roughness or the sphericity of a head or a cup. Therefore, surface polishing is important. It was, however, difficult to polish the central portion of a cup or head using the conventional rotating machine. In the present study, we developed a polishing method combining a pendulum machine and a robotic arm. The effect of the accuracy improvement by this method was evaluated by the friction measurements on some test specimens. Nine balls and a cup of Co-Cr-Mo alloy that were polished by a conventional process using a rotating machine were prepared for the prototype. The average diameter of the balls was 31.9648 mm with the sphericity of 0.0028 μm. The inside diameter of the cup was 31.9850 mm with the sphericity of 0.0044 μm. We combined a robotic arm and a pendulum apparatus to enable the further polishing. The ability of both automatic centering and change in the sliding direction was accomplished by this system. The sliding direction has been changed 180 times every ten degrees. The total distance of polishing was 120 m under vertical load of 100 N in a bath of saline solution containing abrasive grains of silicate of the diameter of 2μm. The surface roughness of the central portion of the cup, which is important area for the fluid film lubrication decreased from Ra 20.2 μm before the polishing to Ra 18.7 μm after the polishing. A pendulum type friction tester was used for the assessment of the improvement of the lubricating ability by the polishing. The measurement was run over at 10 times under the conditions of the load of 600 N in a bath of saline solution. As the result, the frictional coefficients decreased from 0.1456–0.1720 before polishing to 0.1250–0.1300 after polishing. The polishing effect was, however, observed only at the specimens that radial clearances did not exceed the value of 50 μm. The present results indicated that the surface polishing of the central portion of hip prostheses must improve the lubrication ability and the radial clearance before the finishing process should be chinked as possible

Introduction. Background: Trochanteric bursitis is a common and poorly understood complication following total hip arthroplasty (THA). The purpose of this study was to evaluate the incidence of symptomatic trochanteric bursitis and the change in hip offset among THA patients before and after the introduction of robotic assistance. Methods. Retrospective chart review of THAs performed by a single over a 3-year period between 1/5/2013 and 6/28/2016. Between 1/5/2013 and 11/11/2014 101 consecutive patients were identified that underwent manual posterior-lateral THA that utilized traditional cup positioning method based on AP Pelvis radiograph. The subsequent six-month period during a complete transition to robotic arm assistance for posterior-lateral THA was excluded to eliminate any learning curve or selection bias. Between 6/2015 and 6/2016 109 consecutive patients that underwent robotic arm-assisted. Medical records were reviewed for symptomatic trochanteric bursitis within two years of surgery. Hip offset was measured on preoperative and postoperative AP pelvis radiographs and postoperative joint reactive forces were calculated using Martell's Hip Analysis Suite. Results. The rate of symptomatic trochanteric bursitis was 21% in the manual THA population and 10.4% in the population of THAs performed with robotic assistance (P=0.02). The post-operative change in hip offset was significantly higher in patients undergoing traditional THA than patients undergoing robotic arm-assisted THA (5.95 mm vs 4.40 mm; p = 0.0071). Discussion/Conclusion. Transition to robotic arm-assisted THA was associated with decreased incidence of symptomatic trochanteric bursitis and a decreased post-operative change in hip offset

There is an increasing prevalence of haptic devices in many engineering fields, especially in medicine and specifically in surgery. The stereotactic haptic boundaries used in Computer Aided Orthopaedic Surgery Unicomparmental Knee Arthroplasty (CAOS UKA) systems for assistive milling control can lead to an increase in the force required to manipulate the device; this study presented here has seen a several fold increase in peak forces between haptic and non-haptic conditions of a semi-active preoperative image system. Orthopaedic Arthroplasty surgeons are required to apply forces ranging from large gripping forces to small forces for delicate manipulation of tools and through a large range of postures. There is also a need for surgeons to move around and position themselves to gain line of sight with the object of interest and to operate while wearing additional clothing such as the protective headwear and double gloves. These factors further complicate comparison with other ergonomic studies of other robotics systems. While robotics has been implemented to reduce fatigue in surgery one area of concern in CAOS is localised user muscle fatigue in high volume use. In order to create the conditions necessary for the generation of fatigue in a realistic user experience, but in the time available for the participants, an extended period of controlled and prolonged cutting and manipulation of the robotic arm was needed. This pragmatic test requirement makes the test conditions slightly artificial but does indicate areas of high potential for fatigue when interacting with the system in high volume instances. The surgeon-robotic system interaction was captured using 3 dimensional motion analysis and a force transducer embedded in the end effector of the robotic arm and modelled using an existing upper body model in Anybody software. The kinematic and force information allowed initial calculations of the interaction between the user and the Robotic system. Validation of the model was conducted using Electromyography assessment of activity and fatigue. Optimisation of the model sought to create an efficient cutting regime to reduce cutting time with reduced muscle force in an attempt to reduce users discomfort/fatigue while taking into account anthropometric variations in the users and minimising overall energy requirements, burr path length and maximum muscle force. From the assessment of a small group of three surgeons with experience of the Robotic system there was little to no experience of above normal localised fatigue during small volume use of the system. Observation of these surgeons operating the robot state otherwise with examples of reactions to discomfort. There is also anecdotal evidence that fatigue becomes more problematic in higher volume work loads

INTRODUCTION. we have previously reported that bone preparation is quite precise and accurate relative to a preoperative plan when using a robotic arm assisted technique for UKA. However, in that same study, we found a large variation between intended and final tibial implant position, presumably occuring during cement curing. In this study, we reviewed a subsequent cohort of patients in which the tibial and femoral components were cemented individually with ongoing evaluation of tibial component position during cement curing. METHODS AND MATERIALS. Group 1 comprised the simultaneous cementing techniquegroup of patients, previously reported on, although their x-rays were re-analyzed. Group 2 consisted of the individual cementing technique cohort. All implants were identical, specifically a flat, inlay all-polyethylene tibial component. Postoperative x-rays from each cohort of patients were evaluated using image analysis software. Statistical evaluation was performed. RESULTS. In Group 1, average bone preparation was 5.13 + 2.70 degrees of varus and 7.40 + 2.59 degrees of posterior slope. Final implant position was 3.56 + 1.93 degrees of varus and 5.19 + 3.37 degrees of slope. The variance from intended position was 2.31 + 1.74 degrees of varus and 3.80 + 2.90 degrees of slope. For Group 2, average bone preparation was 5.26 + 3.70 degrees of varus and 5.49+ 2.39 degrees of posterior slope. Final implant position was 6.58 + 3.40 degrees of varus and 6.11 + 2.39 degrees of slope. The variance from intended position was 1.82 + 1.42 degrees of varus and 1.39 + 1.48 degrees of slope. ANOVA revealed no differences between groups regarding bone prep in the coronal plane, final implant slope, or variation from intended coronal position. However, bone prep in the sagittal plane showed statistically significant more slope for Group 1 (p = 0.03), increased slope in Group 2 (p=0.004), and greater variation from intended sagital position for Group 1. CONCLUSIONS. Independent cementing of implants showed decreased variation in final tibial component position. However, some implants showed up to 6 degrees of malposition from the intended position. We believe this to be a shortcoming of the inlay style of tibial component for UKA, which even cannot be overcome with the precision and accuracy of a robotic arm assistant

The paper presents the design of a mechatronic assistance system which started from the novel concept to integrate an optical navigation system and a robotic arm, combining the specific advantages of each of the two components. The integrated system offers precise positioning and guiding of surgical instruments according to pre-operative planning. A unique feature results from its capability to track small motions of the patient in real time, eliminating the need to rigidly fix the anatomical structure to be operated. The robot arm can be regarded as a controlled machine actuator of a navigation system. Its operation is mainly controlled by interactive operating modes which are based on a versatile haptic interface. The system supports the surgeon in those parts of a procedure where human skills are limited, but always lets him take full control, for example by directly grasping and moving the arm at its wrist if he wants to push the arm aside. In 2003 several clinical trials have been performed to demonstrate the technical and medical feasibility of the approach. Our mechatronic assistance system has been world’s first system to support the implantation of the acetabular cup in robot assisted hip surgery. The next steps have been concentrated on further developments in some key areas. Improvements of the man-machine interface in order to make the operation of the system faster, easier, and more robust, extension of the system application also to the femoral part of total hip replacement, including support for resurfacing implants, investigation of novel tool systems for bone preparation and prosthesis implantation that fully exploit the advantages of mechatronic, slip-away-safe tool guidance, further improvements for less invasive operating techniques. It has turned out that apart from proving the basic system functionality it is a time consuming task to design all system components in a way that they are robust and easy to handle to be acceptable for daily clinical application. After a partial redesign of the system architecture presently the implementation of improved modules to support both the acetabular and the femoral part in total hip replacement surgery by the mechatronic assistance system is in progress

Background. Use of a robotic tool to perform surgery introduces a risk of unexpected soft tissue damage due to the uncommon tactile feedback for the surgeon. Early experience with robotics in total hip and knee replacement surgery reported having to abort the procedure in 18–34 percent of cases due to inability to complete preoperative planning, hardware and soft tissue issues, registration issues, as well as concerns over actual and potential soft tissue damage. These can result in significant morbidity to the patient, negating all the desired advantages of precision and reproducibility with robotic assisted surgery. The risk of soft tissue damage can be mitigated by haptic software prohibiting the cutting tip from striking vital soft tissues and by the surgeon making sure there is a clear workspace path for the cutting tool. This robotic total knee system with a semi-active haptic guided technique was approved by the FDA on 8/5/2015 and commercialized in August of 2016. Two year clinical results have not been reported to date. Objective. To review an initial and consecutive series of robotic total knee arthroplasties for safety in regard to avoidance of known or delayed soft tissue injuries and the necessity to abort the using the robot to complete the procedure. Report the clinical outcomes with robotic total knee replacement at or beyond two years to demonstrate no delayed effect on expected outcome. Methods. The initial consecutive series of 65 Triathlon. TM. total knee replacements using a semi-active haptic guided system that were performed after commercialization that would be eligible for two year follow-up were reviewed. Pre-operative planning utilizing CT determined the implant placement and boundaries and thus the limit of excursion from any part of the end effector saw tip. Self-retaining retractors were also utilized. Operative reports, 2, 6, and 12 week, and yearly follow-up visit reports were reviewed for any evidence of inadvertent injury to the medial collateral ligament, patellar tendon, or a neurovascular structure from the cutting tool. Operative notes were also reviewed to determine if the robotic procedure was partially or completely aborted due to any issue. Knee Society Knee Scores (KS-KS) and Functional Scores (KS-FS) were recorded from pre-operative and yearly. Any complications were recorded. Results. 40 cases had two year follow-up. The average follow-up for this series was 1.51 years. No cases were unable to be completed robotically. No case had evidence for acute or delayed injury to the medial collateral ligament, patellar tendon, or neurovascular structure. The only complication was a revision total knee for tibial component loosening after a fall induced periprosthetic tibial fracture. Average pre-operative KS-KS and KS-FS improved from 46.9 and 52.1 to 99.2 and 88.6 at one year follow-up, 100.5 and 86.9 at two year follow-up. Conclusions. A semi-active haptic guided robotic system is a safe and reliable method to perform total knee replacement surgery. This series of initial robotic arm assisted surgery had no intraoperative or delayed soft tissue injuries. Preliminary short-term outcomes at up to two years show excellent outcomes

The use of robotics in total joint arthroplasty is the latest in a long list of expensive technologies that promise multiple positive outcomes, but come with an expensive price tag. In the last decade alone we've seen the same claims for navigation and patient specific instruments and implants. There are various current systems available including a robotic arm, robotic-guided cutting jigs and robotic milling systems. For robotics to be widely adopted it will need to address the following concerns, which as of 2017 it has not. 1). Cost - Very clearly the robotic units come with a significant price tag. Perhaps over time, like other technologies, they will reduce, but at present they are prohibitive for most institutions. 2). Outcomes - One could perhaps justify the increased costs if there was compelling evidence that either outcomes were improved or revision rates reduced. Neither of these has been proved in any type of randomised trial or registry captured data. As with any new technology one must be wary of the claims superseding the results. In 2017 the jury is still out on the cost vs. benefit of robotic-assisted TKA

Background. Manually instrumented knee arthroplasty is associated with variability in implant and limb alignment and ligament balance. When malalignment, patellar maltracking, soft tissue impingement or ligament instability result, this can lead to decreased patient satisfaction and early failure. Robotic technology was introduced to improve surgical planning and execution. Haptic robotic-arm assisted total knee arthroplasty (TKA) leverages three-dimensional planning, optical navigation, dynamic intraoperative assessment of soft tissue laxity, and guided bone preparation utilizing a power saw constrained within haptic boundaries by the robotic arm. This technology became clinically available for TKA in 2016. We report our early experience with adoption of this technique. Methods. A retrospective chart review compared data from the first 120 robotic-arm assisted TKAs performed December 2016 through July 2018 to the last 120 manually instrumented TKAs performed May 2015 to January 2017, prior to introduction of the robotic technique. Level of articular constraint selected, surgical time, complications, hemoglobin drop, length of stay and discharge disposition were collected from the hospital record. Knee Society Scores (KSS) and range of motion (were derived from office records of visits preoperatively and at 2-weeks, 7-weeks and 3-month post-op. Manipulations under anesthesia and any reoperations were recorded. Results. Less articular constraint was used to achieve balance in the robotic group, with a higher incidence of cruciate retaining retention (92% vs. 55%, p < 0.01) and a trend towards lower use of varus-valgus constrained articulations (5% vs. 11%, p = 0.068). Robotic surgery increased mean operative time by 22 minutes (p < 0.001). Operative time improved by 26 minutes from the first 10 robotic cases to the last 10 robotic cases. The robotic group had a lower hospital length of stay (2.7 vs. 3.4 days, p < 0.001). Discharge home was not significantly different between robotic and manual groups (89% vs. 83%, p = 0.2). Postoperative Knee Society scores were similar between groups at each postoperative time interval. Robotic-arm assisted TKA patients demonstrated lower mean flexion contracture at 2-weeks (1.8 vs. 3.3 degrees, p < 0.01), 7-weeks (1.0 vs. 1.8 degrees, p <0.01), and 3-months (0.6 vs 2.1 degrees, p = 0.02) post-surgery, but these differences were small. Mean flexion did not differ between groups at 3-month follow-up, but motion was achieved with a significantly lower rate of manipulation under anesthesia in the robotic group (4% vs 17%, p = 0.013). Conclusion. Preliminary findings demonstrate robotic-arm assisted TKA is safe and efficacious with outcomes comparable, if not superior, to that of manually instrumented TKA. Keywords. total knee arthroplasty, robotic arm-assisted total knee arthroplasty. For any figures or tables, please contact authors directly

Introduction. The purpose of this study is to compare total and rate of caloric energy expenditure between conventional and robotic-arm assisted total knee arthroplasty (TKA) between a high volume “veteran” surgeon (HV) and a lower volume, less experienced surgeon (LV). Methods. Two specialized arthroplasty surgeons wore a biometric-enabled shirt and energy expenditure outcomes were measured (total caloric expenditure, kilocalories per minute, heart rate variability, and surgical duration) during 35 conventional (CTKA) and 29 robotic primary total knee arthroplasty (RTKA) procedures. Results. Overall, the rate of caloric expenditure was similar between RTKA (5.60 ±2.50 kcal/min) and CTKA (4.79cal/min ±1.79, p=0.25). With 6.15 minute longer operative times, the total energy expenditure (TEE) for RTKA (239.31±96.79 kcal) was higher thanCTKA(181.54 ±80.90 kcal, p<0.001). The HV surgeon's TEE (p<0.001) and rate of energy expenditure (REE) (p<0.001) were significantly higher in RTKA (261.53cal; 6.499cal/min) versus CTKA (71.00cal; 3.759cal/min). However, the LV surgeon's TEE and REE for RTKA (207.83cal; 4.32cal/min) and CTKA (195.81cal; 4.92cal/min) were not significantly different (p>0.05). Both surgeons (HV; LV) had significantly longer surgical durations (p<0.001) in RTKA (40.41 ±4.94min; 48.91 ±8.45min) compared to CTKA surgeries (18.75±4.27min; 40.4 ±8.34min), respectively. Conclusion. While REE did not varybetween CTKA and RTKA for the LV surgeon, it did vary significantly for the HV surgeon. Additionally, RTKA took longer and increased TEE, but one less operating room assistant was needed. Surgeons with less experience in TKA may be less likely to notice a difference in energy expenditure when utilizing robotic-arm assisted technology. It is possible that more experience with using the robotic arm could create efficiencies over time that may also reduce TEE

To introduce a new robot-assisted surgical system for spinal posterior fixation which called TiRobot, based on intraoperative three-dimensional images. TiRobot has three components: the planning and navigation system, optical tracking system and robotic arm system. By combining navigation and robot techniques, TiRobot can guide the screw trajectories for orthopedic surgeries. In this randomised controlled study approved by the Ethics Committee, 40 patients were involved and all has been fully informed and sign the informed consent. 17 patients were treated by free-hand fluoroscopy-guided surgery, and 23 patients were treated by robot-assisted spinal surgery. A total of 190 pedicle screws were implanted. The overall operation times were not different for both groups. None of the screws necessitated re-surgery for revised placement. In the robot-assisted group, assessment of pedicle screw accuracy showed that 102 of 102 screws (100%) were safely placed (<2 mm, category A+B). And mean deviation in entry point was 1.70 +/− 0.83mm, mean deviation in end point was 1.84 +/− 1.04mm. In the conventional freehand group, assessment of pedicle screw accuracy showed that 87 of 88 (98.9%) were safely placed (<2 mm, category A+B), 1 screw fall in category C, mean deviation in entry point was 3.73 +/− 2.28mm, mean deviation in end point was 4.11 +/− 2.31mm. This randomised controlled study verified that robot-assisted pedicle screw placement with real-time navigation is a more accuracy and safer method, and also revealed great clinical potential of robot-assisted surgery in the future

Purpose. The goal of Total Ankle Arthroplasty (TAA) is to relieve pain and restore healthy function of the intact ankle. Restoring intact ankle kinematics is an important step in restoring normal function to the joint. Previous robotic laxity testing and functional activity simulation showed the intact and implanted motion of the tibia relative to the calcaneus is similar. However there is limited data on the tibiotalar joint in either the intact or implanted state. This current study compares modern anatomically designed TAA to intact tibiotalar motion. Method. A robotic testing system including a 6 DOF load cell (AMTI, Waltham, MA) was used to evaluate a simulated functional activity before and after implantation of a modern anatomically designed TAA (Figure 1). An experienced foot and ankle surgeon performed TAA on five fresh-frozen cadaveric specimens. The specimen tibia and fibula were potted and affixed to the robot arm (KUKA Robotics Inc., Augsburg, Germany) while the calcaneus was secured to a fixed pedestal (Figure 1). Passive reflective motion capture arrays were fixed to the tibia and talus and a portable coordinate measuring machine (Hexagon Metrology Group, Stockholm, Sweden) established the location of the markers relative to anatomical landmarks palpated on the tibia. A four camera motion capture system (The Motion Monitor, Innovative Sports Training, Chicago, IL) recorded the movement of the tibia and talus. The tibia was rotated from 30 degrees plantar flexion to 15 degrees dorsiflexion to simulate motions during the stance phase of gait. At each flexion angle the robot found the orientation which zeroed all forces and torques except compressive force, which was either 44N or 200N. Results. Preliminary data indicates the tibiotalar motion of the TAA is similar to the intact ankle. The pattern and magnitude of tibiotalar translations and rotations are similar between the intact and implanted states for both 44N and 200N compressive loads (Figure 2). The most variation occurs with internal-external rotation. Increased translation especially in the anterior-posterior directions was observed in plantarflexion while the mediolateral translation remained relatively centered moving less than a millimeter. The intact talus with respect to the calcaneus had less than 3 degrees of rotation over the whole arc of ankle flexion (Figure 3). The angular motion of the implanted talus was similar in pattern to the intact talus, however there were offsets in all three angular directions which changed depending on the loading (Figure 3). This indicates that most of the motion that occurs between the intact tibial calcaneal complex occurs in the tibiotalar joint. Conclusion. Although more investigation is required, this study adds to the limited available tibiotalar kinematic data. This current study suggests the anatomical TAA design allows the tibiotalar joint to behave in similar way to the intact tibiotalar joint. Restoring intact kinematics is an important step in restoring normal function to the joint. For figures/tables, please contact authors directly.

Abstract

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.

Aims

The aim of this study was to assess the accuracy of pedicle screw placement, as well as intraoperative factors, radiation exposure, and complication rates in adult patients with degenerative disorders of the thoracic and lumbar spines who have undergone robotic-navigated spinal surgery using a contemporary system.

Introduction. The longevity of total hip arthroplasty (THA) is dependent on acetabular component position. We measured the reliability and accuracy of a CT-based navigation system to achieve the intended acetabular component position and orientation using three dimensional imaging. The purpose of the current study was to determine if the CT-guided robotic navigation system could accurately achieve the desired acetabular component position (center of rotation (COR)) and orientation (inclination and anteversion). The postoperative orientation and location of the components was determined in 20 patients undergoing THA using CT images, the gold standard for acetabular component orientation. Methods. Twenty primary unilateral THA patients were enrolled in this IRB-approved, prospective cohort study to assess the accuracy of the robotic navigation system. Pre- and post-operative CT exams were obtained and aligned 3D segmented models were used to measure the difference in center of rotation and orientation (anteversion and inclination). Patients with pre-existing implants, posttraumatic arthritis, contralateral hip arthroplasty, septic arthritis, or previous hip fracture were excluded. All patients underwent unilateral THA using robotic arm CT-guided navigation (RIO Makoplasty; MAKO Surgical Corp). Results. Mean age was 59.25 years (±8.65 years), 55% of patients were female (11/20). Root mean square (RMS) errors between the intended intraoperative and actual postoperative COR position was measured in the medial/lateral (M/L), superior/inferior (S/I), and anterior/posterior (A/P) directions to quantify the accuracy of the CT-based robotic navigation system. The error in COR was variable (Fig. 4). The M/L distance error was 1.29 mm (SD: 1.18 mm; range: −2.61 – 1.13 mm). The S/I distance error was 1.81 mm (SD: 1.56 mm; range: −2.19 – 3.0 mm). The A/P distance error was 1.50 mm (SD: 1.50 mm; range: −3.53 – 2.23 mm). The mean difference between the intraoperative intended anteversion and postoperative actual anteversion was 2.2° ±1.6° with an RMS error of 2.73°. The mean difference in intraoperative intended inclination and postoperative actual inclination was 3.3° ± 1.7° with an RMS error of 3.71°. The robotic navigation system was more reliable in achieving the intended anteversion than intended inclination. The ICC for anteversion was 0.92 (95% CI 0.91–0.97), compared to ICC 0.74 (95% CI 0.49–0.89) for inclination. Conclusion. Our results suggest that CT-based navigation for THA is accurate for achieving intended cup center of rotation and both reliable and accurate in reproducing the intended cup orientation. Future research will focus on the use of a CT-based robotic navigation system to assist surgeons in the execution of a kinematic-based plan to eliminate impingement to reduce THA instability while maximizing range of motion

While image guidance and neuro-navigation have enabled a more accurate positioning of pedicle implants, robot-assisted placement of pedicle screws appears to overcome the disadvantages of the two first systems. However, recent data concerning the superiority of robots currently available to assist spinal surgeons in the accurate positioning of implants are conflicting. The aim of our study was to evaluate the percentage of accurate positioning of pedicle screws inserted using a new robotic-guidance system. Patients were operated on successively by the same surgeon using robotic-assistance (RA; n=40) or by the freehand conventional technique (FH; n=54). Ten and eleven patients from the robot (RG) and freehand (FHG) groups respectively, age-matched and all suffering from degenerative lumbar spine disease were compared. Patient characteristics as well as the duration of the operation and of exposure to X-rays were recorded. The Gertzbein Robbins classification was used to evaluate implant placement. Data wer compared between the groups. Pedicle screw placement in RG patients was achieved using the ROSA™ (Medtech) robot comprising a compact robotic arm on a floor-fixable mobile base. By permanently monitoring the patient's movements, this image-guided tool helps more accurately to pinpoint the pedicle entry point and to control the trajectory. The mean age of patients in each group (RG and FHG) was 63 years. Mean BMI and operating time among the RG and FHG were respectively 26 and 27 kg/m. 2. , and 187 and 119 min. Accurate placement of the implant (score A-B) was achieved in 97.2% of patients in the RG (n=36) and in 92.6% of those in the FHG (n=54). Four implants in the RG were placed manually following failed robotic assistance. The mean duration of X-ray exposure per patient was 1 min 42s in the RG and 41s in the FHG. We report a higher rate of accuracy with robotic assistance as compared to the FH technique. Exposure time was greater in the RG partly due to the fluoroscopic control of the implants required for this pilot study of feasibility. Limitations of the study include its small sized and non-randomised sample. Nevertheless, these preliminary results are encouraging for the development of new robotic techniques for spinal surgery

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.

INTRODUCTION:. Unicompartmental knee replacement (UKR) facilitates the use of smaller sized implants that require less bone resection and allows preservation of the anterior and posterior cruciate ligaments (ACL and PCL)[1]. Therefore, UKR preserves the intact kinematics and may improve the clinical outcomes especially compared to the outcomes of total knee replacement (TKA). Despite the known benefits of UKR in arthritis limited to one compartment, in multicompartment disease TKA remains the gold standard. Current TKA designs require the sacrifice of the ACL in all cases, whereas the surgeon can decide to use a cruciate sparing or substituting design altering normal knee kinematics. Performing bi-UKR or tri-UKR with traditional instruments is very challenging and rarely done due to the difficulty in establishing the correct spatial relationship of the separate components. Recent advances in robotic surgery have provided the opportunity to utilize partial knee replacements. The MAKO Rio platform is a surgeon-interactive robotic arm with haptic guidance that allows computer assisted planning and intraoperative accurate placement of multiple unicompartmental components including the bi-UKR. Currently there is a lack of understanding about the short-term and long-term clinical outcomes of the bi-UKR compared to the traditional TKA. OBJECTIVES:. The objective of the current study was to investigate the differences in the clinical outcomes of bi-UKR and TKA. METHODS:. In the current study the clinical outcomes of the patients in three groups were obtained who were operated by the same surgeon. Table-1 shows the demographics of the participants. All patients were evaluated via Knee Injury Osteoarthritis Outcome Score (KOOS) and the scores were compared to reported scores from standard TKA. One-way ANOVA was performed to determine significance within demographics. The signed consent was obtained from each participant. RESULTS:. Post-operative data were collected at a mean followup time of 12.3 months. The results indicated higher KOOS in individuals in group-1 compared to TKA individuals. No intraoperative complications during implantation were noted for the bi-UKR group. At the latest followup, no revision surgery was required for any of the subjects. CONCLUSION:. Our experience with the bi-UKR has shown promising clinical outcomes with no post-operative complications. These outcomes may be explained by the less invasive nature of bi-UKR surgeries that preserves of the integrity of the both the ACL and PCL ligaments. Additionally, there is a more accurate joint line reconstruction compared to TKA which may reproduce the functional capabilities of the intact knee more closely. Considering these advantages in addition to preservation of bone and less soft tissue destruction, robotically assisted multi-compartment knee replacement may be a viable alternative treatment in select patients

Aims

Postoperative length of stay (LOS) and discharge dispositions following arthroplasty can be used as surrogate measurements for improvements in patients’ pathways and costs. With the increasing use of robotic technology in arthroplasty, it is important to assess its impact on LOS. The aim of this study was to identify factors associated with decreased LOS following robotic arm-assisted total hip arthroplasty (RO THA) compared with the conventional technique (CO THA).

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.

Introduction:. Following total knee arthroplasty, patients often complain of an unnatural feeling in their knee joint, which in turn limits their activities [Noble et al, CORR 2006]. To develop an implant design that recreates the motion of the natural knee, both the functional kinematics as well as the laxity of the joint need to be understood. In vitro testing that accurately quantifies the functional kinematics and laxity of the knee joint can facilitate development of implant designs that are more likely to result in a natural feeling, reconstructed knee. The objective of this study is to demonstrate that robotic in vitro testing can produce clinically relevant functional kinematics and joint laxities. Methods:. All testing was performed using a KUKA (KUKA Robotics, Augsburg, Germany) 6 degree of freedom robotic arm and a six degree of freedom load cell (ATI Industrial Automation, Apex, North Carolina, USA), attached to the arm (Figure 1). FUNCTIONAL KINEMATICS: Eight cadaveric specimens implanted with contemporary cruciate retaining implants were used for this evaluation. The functional activity, lunge, was simulated using kinematic control for flexion/extension and force-torque control for the other degrees of freedom. The inputs for the force-torque control were obtained from e-tibia data from live patients during the lunge activity [Varadarajan et al, J Biomech 2008]. At a given flexion angle, the robot moved in force-torque control to obtain the desired values within given tolerances (± 2.5N & ± 0.1 Nm). When these tolerances were met the position of femur with respect to the tibia was recorded and the knee flexed to the next level. The lunge simulation began at full extension and ended at 120 degrees of knee flexion, through 1 degree increments. The kinematic data from the contemporary CR implants were compared to in vivo kinematics of patients that were implanted with the same knee replacements performing a lunge activity [Varadarajan et al, Med Eng Phys 2009]. JOINT LAXITY: Eight native, unimplanted knees were used for this evaluation. Joint laxity of the knee joint was evaluated at 0, 30, 60, 90, and 120 degrees of knee flexion by applying various loads to the tibia and quantifying the resulting motion of the tibia. The resulting laxities were compared to various knee laxity studies in the literature. Results:. The in vitro functional kinematics correlated well with the in vivo results. Femoral external rotation and tibial varus angulation were found not be statistically different between the in vitro and in vivo results (Figure 2). The laxities measurements correlated well with reported values in the literature. Discussion:. In vitro robotic evaluations allow for a better understanding of the motion at the knee joint by simulating clinically relevant functional kinematics as well as quantifying joint laxities in the same testing system. Both of these metrics are needed to understand how the knee moves and should be used to evaluate the performance of new knee designs (Figure 3)

Introduction. In total hip arthroplasty, the positioning of the acetabular cup, in particular, has been shown to play an important role in the survivorship of the prosthetic joint. The commonly accepted “safe zone” extends from 5–30° of anteversion to 30–50° of inclination. However, several studies have utilized a more restrictive safe zone of 5–25° of anteversion and 30–45° of inclination, a modification of the Lewinnek zone. Many attempts have been made to develop a more reliable method of positioning the acetabular component. Robotic-assisted surgery is one such method. The purpose of this study was to compare the resulting position of the acetabular component after robotic-assisted surgery with the intraoperative robotic data to determine if improved accuracy can be achieved with the robotic-assisted method. Methods. One hundred and nineteen patients received THA, at four different medical centers in the United States, using a haptic robotic arm. Pre-operative CT scans were obtained for all patients and used during the planning of the procedure, at which point the proposed component size and positioning was determined. Preparation of the acetabular bone bed, as well as impaction of the acetabular component itself, was performed using the robotic device. Using an AP Pelvis and Cross-Table Lateral radiograph, each patient's resulting acetabular inclination and version was measured using the Hip Analysis Suite software. The component position retrieved from the robot was compared to the measured values from the radiographs. The positioning data was compared to two safe zones described above. Results. Of the 119 surgeries performed, 110 could be read with the hip analysis suite software. Radiographically, the average inclination was 40.4° ± 4.1° with a range of 27.4°–53.7° and the average anteversion was 21.5° ± 6.1° with a range of 5.2°–42.6°. As measured inter-operatively, 100% of the components fell within the Lewinnek safe zone and 96% fell within the more restrictive safe zone. Radiographically, 88% of the cases fell within the Lewinnek safe zone and 73% fell within the restrictive safe zone. The mean difference between the inclination and version of the component determined by the robot and by radiographic analysis was 0.31° and 2.1° respectively. Conclusions. The inclination and version of the acetabular components implanted with robotic assistance as determined inter-operatively were within the commonly accepted limits in all cases. Variations between the cup positions determined inter-operatively and from the post-operative radiographs are related to differences in the radiographic project of the hip and the robotic registration of the pelvis from CT images. In no procedure was the radiographic inclination greater than 54° or version less than 5°. In this study, the use of robotic-assisted positioning of the acetabular component has significantly reduced the variability of component orientation. This improved reliability of positioning should result in an increase of favourable functioning, and a decrease in early complications such as dislocation, impingement, and component wear

Introduction: Functional results of hemiarthroplasties in proximal humeral fractures are unpredictable. The correct consolidation of the tuberosities back to the prosthesis seem to be of capital importance in the functional outcome. The objective of the study is to analyze the changes of the tension registered in the sutures passed through the tuberosities when changing the height and version of the prosthesis in a static model and in a dynamic model. Material and Method: Prosthesis positioning: in both static and dynamic model, the prosthesis was placed in anatomical position, anatomical increasing 20° retroversion, increasing height in 1cm and anatomical version, decreasing height in 1 cm and anatomical version, increasing height in 1cm and increasing 20° retroversion, decreasing height in 1 cm and increasing 20° retroversion,. Static study: a 4-part fracture was reproduced in four fresh-frozen shoulder specimens. Sutures were placed between lesser tuberosity and diafisis (sensor 1) between both tuberosities (sensor 2) and between greater tuberosity and diafisis (sensor 3). Traction was performed through supraspinatus, infraspinatus and subescapularis attachments until the breakage of the suture or 1 cm gap between bony fragments. Tensions registered in a computer model. Dynamic study: a 4-part fracture was reproduced in a humeral saw bone. Sutures placed in the same position that in the static model. Saw bone fixed at a robotic arm reproducing cycles of 90° anterior elevation, 30° lateral rotation, 30° internal rotation and retropulsion to starting point. Registering of the tensions. Quantitative values studied through t-student and non parametric values studied through U-Mann-Whitney and Kruskal-Wallis test. Results: In the Static study, the suture placed between the tuberosities is the one that significantly receives more tension. The breakage of the suture happens more frequently when the prosthesis is placed in a lower position and in a lower more retroverted position. In the dynamic study, the suture placed between the greater tuberosity and the diafisis is the one significantly receives more tension. The breakage of the suture happens more frequently when the prosthesis is placed in a lower position and in a lower more retroverted position. Conclusions: When planning sutures between tuberosities in proximal humeral fractures treated with hemiarthroplasty postoperative rehabilitation program has to be considered because different sutures are at risk depending on static or dynamic model. The worst positions of the hemiarthroplasty as far as over tensioning sutures is concerned are the low position and the low more retroverted position

The December 2022 Hip & Pelvis Roundup³⁶⁰ looks at: Fix and replace: simultaneous fracture fixation and hip arthroplasty for acetabular fractures in older patients; Is the revision rate for femoral neck fracture lower for total hip arthroplasty than for hemiarthroplasty?; Femoral periprosthetic fractures: data from the COMPOSE cohort study; Dual-mobility cups and fracture of the femur; What’s the deal with outcomes for hip and knee arthroplasty outcomes internationally?; Osteochondral lesions of the femoral head: is costal cartilage the answer?

Introduction. Clinical outcomes of UKA procedures are sensitive to malalignment of the components, and thus show significant variability in the literature. A new robotic procedure addresses isolated medial compartment osteoarthritis with the classic indications of UKA. Using precision planning through patient specific 3D modeling and reconstruction, a robotic arm gives the surgeon control of resurfacing the knee joint, allowing for consistent precision according to the previously chosen plan. Through the precise preparation of bone surfaces and inter-component alignment, this procedure is designed to significantly increase accuracy and decrease mal-alignment, thus increasing post-operative physical and function outcomes. This paper evaluates four year clinical outcomes of this novel surgical procedure. Methods. The first seventy-three (42 male, 31 female) patients (average age: 71 ±10yrs) to receive a robotically assisted UKA enrolled in an IRB approved outcomes registry. Eleven patients were four years post operative and sixty-two patients were three years post operative at the time of the study. The average follow ups were 45 months and 35 months, respectively (range: 30 to 47 months). The tibial component for all patients was an all-poly inlay design. Results. At one, two, three and four year follow up, all patients showed significant improvements, compared to pre-operative values, in range of motion (p<0.05), Knee Society Knee (p<0.001) and Function (p<0.001) scores, sf-12 PCS scores (p<0.001). Two patients have been revised, for a four year clinical failure rate of 2.34% at an average follow-up of 37 months. Both revisions were due to loosening of the tibial component and occurred at 23.6 and 17.5 months, respectively, after the index procedure. The first was revised to a TKA. The second patient (age 50, BMI 27.2) was revised to a unicompartmental onlay tibial component at 17.5 months after presenting with weight bearing pain in the medial compartment. Upon explantation of the inlay component, the surgeon observed perfect cement-to-bone integration and noted that the failure was due to debonding of the undersurface of the poly to the cement. Optimal alignment of the femur to the tibia remained intact and the patient showed no signs of progressing OA disease. The bone preserving nature of the original inlay tibial component preparation allowed the surgeon to convert the patient to an onlay component with minimal bone resection instead of conversion to a TKA. A cement channel has been added to the inlay design to improve cement fixation effectiveness. In addition, the undersurface of the tibial component has since been removed and replaced with a dovetail channel to improve lift-off resistance of the tibial inlay. This new design has shown to be 10 times stronger in laboratory push out tests. Conclusions. This initial series of robotically guided UKA implantations provided significant improvement in the post-operative function of patients in every functional measurement with only two revisions to date, likely for improper patient selection. The introduction of new procedures and technologies in medicine is routinely fraught with issues associated with learning curves and unanticipated pitfalls. Because the explicit objectives of this novel technology are to optimize surgical procedures to provide more safe and more reliable outcomes, these favorable results provide the potential for significant improvements in orthopedic surgery

Formal surgical skill assessment and critical path analysis are not widely used in orthopaedic surgical training due to the lack of technology for objective quantification, reliability, and the discrimination insensitivity of existing methods. Current surgical skill assessment methods also require additional instrumentation, cost and time. Such problems can be overcome by a novel method that records the motion of surgical instrumentation for the purposes of documentation, surgical-skill assessment, and safety analysis. This method uses an existing computer-aided-orthopedic-surgery (CAOS) navigation system and does not compromise its functions of real-time tracking, rendering, or simulation. The stored data allows realistic playback in 3D of the complete bone cutting/refining process. This concept and its sensitivity were previously tested and validated using a robotic arm as a reliable actuator for a surgical instrument moving in controlled paths. In this study, the system was used to evaluate the surgical skills of actual orthopaedic residents in a hospital/lab setting. Two chief orthopaedic surgery residents participated in the experiment. Each one cut all five distal cuts on four synthetic (right) femurs to accommodate the same femoral implant using NoMiss, an in-house built system for Navigated Freehand bone cutting. The motion of the surgical saw was recorded in real time by NoMiss during the whole procedure, but the real purpose of the experiment (and the recording) was not revealed to the residents until the end of all tests. Based on the data recorded by the navigation system, the following parameters were analyzed: cutting time, area-of-the-cut/time ratio, trajectory of the saw, errors in distance off the plane as well as errors in roll and pitch angles. While no significant difference among the two subjects was found in bone cutting time (mean 531s vs. 642s, p=0.099), subject 1 (S1) was faster than subject 2 (S2) in total time, which included cutting, reshaping of the bone, and implantation (mean 719s vs. 958 s, p=0.035). Area-of-the-cut/time ratio revealed higher (not significant) proficiency for S1 compared to S2 (mean 16 mm2/s vs. 13 mm2/s, p=0.084). Nevertheless considering individual cuts, there was significant difference in the posterior chamfer cut (mean 9 vs. 5 mm2/s, p=0.015). The analysis of the trajectory of the saw showed less conservative motion (and less consistency) for S1 than for S2 (average total length of trajectory 8.6m (sd=2.1m) vs. 8.1m (sd=0.4m), as well as larger paths in between cuts (average 39% vs. 33% of the total trajectory). The system/method was able to characterize different subjects without additional instrumentation, cost, time, awareness of or distraction to the user. Slightly better performance was detected for S1 compared to S2 presumably signifying superior skills. The main differences in this case appeared in the cutting of the chamfers, which might be considered the trickiest of the distal cuts in a navigated freehand cutting environment. A larger number of subjects with a wide level of expertise should be analyzed under similar conditions to establish quantitative acceptance limits (e.g. numerical determination for pass/fail criteria)

Aims

Traditionally, acetabular component insertion during total hip arthroplasty (THA) is visually assisted in the posterior approach and fluoroscopically assisted in the anterior approach. The present study examined the accuracy of a new surgeon during anterior (NSA) and posterior (NSP) THA using robotic arm-assisted technology compared to two experienced surgeons using traditional methods.

Aims

No predictive model has been published to forecast operating time for total knee arthroplasty (TKA). The aims of this study were to design and validate a predictive model to estimate operating time for robotic-assisted TKA based on demographic data, and evaluate the added predictive power of CT scan-based predictors and their impact on the accuracy of the predictive model.

Aims

Total knee arthroplasty (TKA) using functional alignment aims to implant the components with minimal compromise of the soft-tissue envelope by restoring the plane and obliquity of the non-arthritic joint. The objective of this study was to determine the effect of TKA with functional alignment on mediolateral soft-tissue balance as assessed using intraoperative sensor-guided technology.

Aims

This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

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.

Aims

Ideal component sizing may be difficult to achieve in unicompartmental knee arthroplasty (UKA). Anatomical variants, incremental implant size, and a reduced surgical exposure may lead to over- or under-sizing of the components. The purpose of this study was to compare the accuracy of UKA sizing with robotic-assisted techniques versus a conventional surgical technique.

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).

Aim

There has been a significant reduction in unicompartmental knee arthroplasty (UKA) procedures recorded in Australia. This follows several national joint registry studies documenting high UKA revision rates when compared to total knee arthroplasty (TKA). With the recent introduction of robotically assisted UKA procedures, it is hoped that outcomes improve. This study examines the cumulative revision rate of UKA procedures implanted with a newly introduced robotic system and compares the results to one of the best performing non-robotically assisted UKA prostheses, as well as all other non-robotically assisted UKA procedures.

Aims

The aim of this study was to systematically compare the safety and accuracy of robot-assisted (RA) technique with conventional freehand with/without fluoroscopy-assisted (CT) pedicle screw insertion for spine disease.

Objectives

The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, component inclination, component version, and leg-length correction.

Aims

The objectives of this study were to assess the effect of anterior cruciate ligament (ACL) resection on flexion-extension gaps, mediolateral soft tissue laxity, maximum knee extension, and limb alignment during primary total knee arthroplasty (TKA).

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.

Introduction. Bicompartmental osteoarthritis involving the medial tibiofemoral and the patellofemoral compartments is often treated with total knee replacement. Improved implants and surgical techniques have led to renewed interest in bicompartmental arthroplasty. This study evaluates the radiographic and early clinical results of bicompartmental arthroplasty with separate unlinked components implanted with the assistance of a robotic surgical arm. In addition, we examine the amount of bone resected using unlinked bicompartmental components compared to total knee replacement. Finally, a retrospective review of total knee cases examines the applicability of this early intervention procedure. Methods. 97 patients received simultaneous but geometrically separate medial tibiofemoral and patellofemoral arthroplasties with implants specifically designed to take advantage of a new bone and tissue sparing implantation technique using haptic robotics. These patients came from four surgeons at four different hospitals. The average follow-up was 9 months. Pre- and post-operative radiographs were taken. ROM, KSS and WOMAC scores were recorded. The patients had an average age of 67 yrs (range: 45-95), BMI of 29 ± 4kg/m. 2. 47% of the patients were male. We retrospectively reviewed pre and post operative notes from 406 consecutive TKA patients from a single surgeon. Intraoperative data included the integrity of the three compartments and the ACL. Results. At only six weeks follow-up, patients recovered their pre-operative ROM (p=0.37). Knee Society Knee scores (knee and function) and WOMAC scores (pain, function and total) significantly improved from pre-operative values at every follow-up of 6 weeks, 6 months and 1 year (p<0.05). Radiographically, there was no evidence of loosening, wear or progression of OA. There were also no perioperative complications. Using computer simulation, the amount of bone removed using bicompartmental arthroplasty compared to traditional TKA was predicted. Total bone removed on the femur and the tibia using a standard TKA implant is 3.5 times the bone removed using a bicompartmental onlay implant and 4 times the bone removed when using a bicompartmental inlay implant. In the review of 406 TKA cases, the ACL was intact in 66% of these cases. Based on these data alone, 16% of these TKA patients were indicated for a unicondylar arthroplasty, 12% medial UKA, 3% lateral UKA and 1% PFA. In addition, 31% were indicated for bicompartmental arthroplasty with 4% bicondylar (medial and lateral UKA), 6% lateral UKA and PFA and 21% medial UKA and PFA. While these data don't yet account for fixed versus flexible deformities, excessive osteophytes or other contraindications, it seems clear that the disease often treated with a TKA does not actually involve all three compartments. Conclusions. Modular bicompartmental arthroplasty is an effective method for treating arthritis of the knee restricted to the medial and patellofemoral compartments. Early results using contemporary prostheses are encouraging and should prompt further mid- and long-term study. Robotic assistance of bicompartmental arthroplasty has shown good early clinical and radiographic success. In addition, bicompartmental arthroplasty removes significantly less bone than total knee arthroplasty. Also, data indicates that may total knee patients have healthy cruciates and disease in only two of the three compartments, indicating that TKA is an overtreatment of earlier stage osteoarthritis. Longer term studies will determine the clinical significance of preserving healthy cartilage and ligaments routinely resected with traditional tricompartmental TKA

Aims

The purpose of this multicentre observational study was to investigate the association between intraoperative component positioning and soft-tissue balancing on short-term clinical outcomes in patients undergoing robotic-arm assisted unicompartmental knee arthroplasty (UKA).

Aims

Limited evidence is available on mid-term outcomes of robotic-arm assisted (RA) partial knee arthroplasty (PKA). Therefore, the purpose of this study was to evaluate mid-term survivorship, modes of failure, and patient-reported outcomes of RA PKA.

Objectives

The use of the haptically bounded saw blades in robotic-assisted total knee arthroplasty (RTKA) can potentially help to limit surrounding soft-tissue injuries. However, there are limited data characterizing these injuries for cruciate-retaining (CR) TKA with the use of this technique. The objective of this cadaver study was to compare the extent of soft-tissue damage sustained through a robotic-assisted, haptically guided TKA (RATKA) versus a manual TKA (MTKA) approach.

Aims

Computer-based applications are increasingly being used by orthopaedic surgeons in their clinical practice. With the integration of technology in surgery, augmented reality (AR) may become an important tool for surgeons in the future. By superimposing a digital image on a user’s view of the physical world, this technology shows great promise in orthopaedics. The aim of this review is to investigate the current and potential uses of AR in orthopaedics.

Aims

The aim of this study was to evaluate the accuracy of implant placement when using robotic assistance during total hip arthroplasty (THA).

Aims

The aim of this study was to assess the effect of posterior cruciate ligament (PCL) resection on flexion-extension gaps, mediolateral soft-tissue laxity, fixed flexion deformity (FFD), and limb alignment during posterior-stabilized (PS) total knee arthroplasty (TKA).

Aims

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

Aims

The primary aim of this study was to determine the surgical team’s learning curve for introducing robotic-arm assisted unicompartmental knee arthroplasty (UKA) into routine surgical practice. The secondary objective was to compare accuracy of implant positioning in conventional jig-based UKA versus robotic-arm assisted UKA.

The use of robotics in arthroplasty surgery is expanding rapidly as improvements in the technology evolve. This article examines current evidence to justify the usage of robotics, as well as the future potential in this emerging field.

Robots have been used in surgery since the late 1980s. Orthopaedic surgery began to incorporate robotic technology in 1992, with the introduction of ROBODOC, for the planning and performance of total hip replacement. The use of robotic systems has subsequently increased, with promising short-term radiological outcomes when compared with traditional orthopaedic procedures. Robotic systems can be classified into two categories: autonomous and haptic (or surgeon-guided). Passive surgery systems, which represent a third type of technology, have also been adopted recently by orthopaedic surgeons.

While autonomous systems have fallen out of favour, tactile systems with technological improvements have become widely used. Specifically, the use of tactile and passive robotic systems in unicompartmental knee replacement (UKR) has addressed some of the historical mechanisms of failure of non-robotic UKR. These systems assist with increasing the accuracy of the alignment of the components and produce more consistent ligament balance. Short-term improvements in clinical and radiological outcomes have increased the popularity of robot-assisted UKR.

Robot-assisted orthopaedic surgery has the potential for improving surgical outcomes. We discuss the different types of robotic systems available for use in orthopaedics and consider the indication, contraindications and limitations of these technologies.

The use of robots in orthopaedic surgery is an emerging field that is gaining momentum. It has the potential for significant improvements in surgical planning, accuracy of component implantation and patient safety. Advocates of robot-assisted systems describe better patient outcomes through improved pre-operative planning and enhanced execution of surgery. However, costs, limited availability, a lack of evidence regarding the efficiency and safety of such systems and an absence of long-term high-impact studies have restricted the widespread implementation of these systems. We have reviewed the literature on the efficacy, safety and current understanding of the use of robotics in orthopaedics.

Cite this article: Bone Joint J 2015; 97-B:292–9.

In light of the growing number of elderly osteopenic patients with distal humeral fractures, we discuss the history of their management and current trends. Under most circumstances operative fixation and early mobilisation is the treatment of choice, as it gives the best results. The relative indications for and results of total elbow replacement versus internal fixation are discussed.

We performed a prospective, randomised controlled trial of unicompartmental knee arthroplasty comparing the performance of the Acrobot system with conventional surgery. A total of 27 patients (28 knees) awaiting unicompartmental knee arthroplasty were randomly allocated to have the operation performed conventionally or with the assistance of the Acrobot. The primary outcome measurement was the angle of tibiofemoral alignment in the coronal plane, measured by CT. Other secondary parameters were evaluated and are reported.

All of the Acrobot group had tibiofemoral alignment in the coronal plane within 2° of the planned position, while only 40% of the conventional group achieved this level of accuracy. While the operations took longer, no adverse effects were noted, and there was a trend towards improvement in performance with increasing accuracy based on the Western Ontario and McMaster Universities Osteoarthritis Index and American Knee Society scores at six weeks and three months. The Acrobot device allows the surgeon to reproduce a pre-operative plan more reliably than is possible using conventional techniques which may have clinical advantages.

In a global environment of rising costs and limited funds, robotic and computer-assisted orthopaedic technologies could provide the means to drive a necessary revolution in arthroplasty productivity. Robots have been used to operate on humans for 20 years, but the adoption of the technology has lagged behind that of the manufacturing industry. The use of robots in surgery should enable cost savings by reducing instrumentation and inventories, and improving accuracy. Despite these benefits, the orthopaedic community has been resistant to change. If the ergonomics and economics are right, robotic technology just might transform the provision of joint replacement.