Introduction. The accuracy of hexapod circular external fixator deformity correction is contingent on the precision of radiographic analysis during the planning stage. The aim of this study was to compare the SMART TSF (Smith and Nephew, Memphis, Tennessee) in-suite radiographic analysis methods with the traditional manual deformity analysis methods in terms of accuracy of correction. Materials and Methods. Sawbones models were used to simulate two commonly encountered clinical scenarios. Traditional manual radiographic analysis and digital SMART TSF analysis methods were used to correct the simulated deformities. Results. The final outcomes of all six analysis methods across both simulated scenarios were satisfactory. Any differences in residual deformity between the analysis methods are unlikely to be clinically relevant. All three SMART TSF digital analyses were faster to complete than manual radiographic analyses. Conclusions. With experience and a good understanding of the software, manual radiographic analysis can be extremely accurate and remains the gold standard for deformity analysis. In-suite SMART TSF radiographic analysis is fast and accurate to within clinically relevant parameters. Surgeons can with confidence trust the SMART TSF software to provide analysis and corrections that are clinically acceptable

We present an analysis of manual and computer-assisted preoperative pedicle screw placement planning. Preoperative planning of 256 pedicle screws was performed manually twice by two experienced spine surgeons (M1 and M2) and automatically once by a computer-assisted method (C) on three-dimensional computed tomography images of 17 patients with thoracic spinal deformities. Statistical analysis was performed to obtain the intraobserver and interobserver variability for the pedicle screw size (i.e. diameter and length) and insertion trajectory (i.e. pedicle crossing point, sagittal and axial inclination, and normalized screw fastening strength). In our previous study, we showed that the differences among both manual plannings (M1 and M2) and computer-assisted planning (C) are comparable to the differences between manual plannings, except for the pedicle screw inclination in the sagittal plane. In this study, however, we obtained also the intraobserver variability for both manual plannings (M1 and M2), which revealed that larger differences occurred again for the sagittal screw inclination, especially in the case of manual planning M2 with average differences of up to 18.3°. On the other hand, the interobserver variability analysis revealed that the intraobserver variability for each pedicle screw parameter was, in terms of magnitude, comparable to the interobserver variability among both manual and computer-assisted plannings. The results indicate that computer-assisted pedicle screw placement planning is not only more reproducible and faster than, but also as reliable as manual planning

Introduction. Component position and overall limb alignment following total knee arthroplasty (TKA) have been shown to influence prosthetic survivorship and clinical outcomes. Robotic-assisted (RA) total knee arthroplasty has demonstrated improved accuracy to plan in cadaver studies compared to conventionally instrumented (manual) TKA, but less clinical evidence has been reported. The objective of this study was to compare the three-dimensional accuracy to plan of RATKA with manual TKA for overall limb alignment and component position. Methods. A non-randomized, prospective multi-center clinical study was conducted to compare RATKA and manual TKA at 4 U.S. centers between July 2016 and August 2018. Computed tomography (CT) scans obtained approximately 6 weeks post-operatively were analyzed using anatomical landmarks. Absolute deviation from surgical plans were defined as the absolute value of the difference between the CT measurements and surgeons’ operative plan for overall limb, femoral and tibial component mechanical varus/valgus alignment, tibial component posterior slope, and femoral component internal/external rotation. We tested the differences of absolute deviation from plan between manual and RATKA groups using stratified Wilcoxon tests, which controlled for study center and accounted for skewed distributions of the absolute values. Alpha was 0.05 two-sided. At the time of this abstract, data collections were completed for two centers (52 manual and 58 RATKA). Results. Comparing absolute deviation from plan between groups, RATKA demonstrated clear benefits for tibial component alignment (median absolute deviation from plan: 1.5° vs. 0.8°, manual vs RATKA, p<.001), tibial slope (2.7° vs. 1.1°, manual vs RATKA, p<.001), and femoral component rotation (1.4° vs. 0.9°, manual vs RATKA, p<0.02). Femoral component and overall limb alignment accuracy were comparable (p>0.10). Discussion and Conclusions. In this study, compared to manual TKA, RATKA cases were 47% more accurate for tibial component alignment, 59% more accurate for tibial slope, and 36% more accurate for femoral component rotation (percent differences of median absolute deviations from plan). Further clinical data is needed to study the longer-term benefits of robotic technologies. Nevertheless, this study supports improved accuracy to plan utilizing RATKA compared to manual TKA. For any figures or tables, please contact authors directly

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. Patient specific instruments (PSI) and computer-assisted surgery (CAS) are innovative technologies that offer the potential to improve the accuracy and reproducibility with which a total knee arthroplasty (TKA) is performed. It has not been established whether clinical, functional, or radiographic outcomes between PSI, CAS, and manual TKA differ in the hands of an experienced TKA surgeon. The purpose of this study was to evaluate clinical, functional and radiographic outcomes between TKA performed with PSI, CAS, and manual instruments at short-term follow-up. Our hypothesis was that at early follow-up, we would be unable to elucidate any significant differences between the groups using the most commonly utilized outcomes measures. Methods. 40 PSI, 38 CAS, and 40 manual TKA were performed by a single surgeon. The groups were similar in regards to age, sex, and preoperative diagnosis. The Knee Society Scoring System was used to evaluate patient clinical and functional outcome scores preoperatively and at 1 and 6 months postoperatively. Long-standing AP radiographs were obtained pre and postoperative to evaluate mechanical axis alignment. Results. PSI, CAS, and manual TKA produced similar interval improvements in clinical and functional outcomes at both 1 and 6-months postoperative. Knee Society Knee scores were on average 88.5, 72.5, and 69.3 for PSI, CAS, and manual TKA at 1 month and 99.4, 83.4, and 84.6 at 6 months postoperative. Knee Society Function scores were on average 65.9, 49.3, and 48.4 for PSI, CAS, and manual TKA at 1 month and 86.3, 66.2, and 61.2 at 6 months postoperative. Although PSI tended to have higher absolute Knee and Function scores at 1 and 6 months postoperative, the interval change from preoperative to postoperative between each group was similar. Postoperative mechanical axis alignment was not significantly different between PSI, CAS, and manual TKA (1.0â�°, 2.0â�°, and −0.2â�°, respectively). Discussion. This study suggests that in the hands of an experienced arthroplasty surgeon, PSI, CAS and manual TKA produce similar interval improvements in clinical, functional, and radiographic outcomes at short-term follow-up. These results may reflect the ability of an arthroplasty-trained academic surgeon to perform a TKA accurately with multiple technologies. These findings may also represent the lack of sensitivity and inability of commonly utilized evaluation tools, like plain radiographs and the Knee Society Scoring System, to adequately differentiate small differences in outcomes and limb alignment, if differences do indeed exist. Long-term follow-up will help establish whether these TKA technologies continue to demonstrate equivalent clinical and functional interval improvements

Introduction. Total hip arthroplasty (THA) is a physically demanding procedure where the surgeon is subject to fatigue with increased energy expenditure comparable to exercise[1]. Robotic technologies have been introduced into operating rooms to assist surgeons with ergonomically challenging tasks and to reduce overall physical stress and fatigue[2]. Greater exposure to robotic assisted training may create efficiencies that may reduce energy expenditure[3]. The purpose of this study was to assess surgeon energy expenditure during THA and perceived mental and physical demand. Methods. 12 THAs (6 cadavers) randomized by BMI were performed by two surgeons with different robotic assisted experience. Surgeon 1 (S1) had performed over 20 robotic assisted THAs on live patients and Surgeon 2 (S2) had training on 1 cadaver with no patient experience. For each cadaver, laterality was randomized and manual total hip arthroplasty (MTHA) was performed first on one hip and robotic assisted total hip arthroplasty (RATHA) on the contralateral hip. A biometric shirt collected surgeon data on caloric energy expenditure (CEE) throughout acetabular reaming (AR) and acetabular implantation (AI) for each THA procedure. Surgeon mental and physical demand was assessed after each surgery. Scores were reported from 1–10, with 10 indicating high demand. A paired sample t-test was performed between MTHA and RATHA within each surgeon group with a confidence interval of (α =0.05). Results. Each surgeon demonstrated greater CEE during MTHA, Figure 1. Surgeon CEE during MTHA was greater for S1(100±28.1 cals) compared to RATHA(83.5±0.34 cals), with no significant difference (p>0.05, p=0.49). Energy expenditure was greater for S2 during MTHA(83.5±16.3 cals) compared to RATHA(75.3±0.71 cals) with no significance (p>0.05, p=0.68). RATHA resulted in a decrease in average CEE for each surgeon with a reduction of 16.5% for S1 and 9.8 % for S2. Surgeon task time during MTHA was greater for S1(14.7±3.2 mins) compared to RATHA(12.3±4.93 mins), with no significance (p>0.05, p=0.46). Average task time was greater for S2 during MTHA(10.0±2.65 mins) compared to RATHA(8.7±2.89 mins) with no significant differences (p>0.05, p=0.66). Average mental and physical demand was less for RATHA compared to MTHA, Figure 2. Average physical demand reported during AR for MTHA(5.5±1.2) was greater than RATHA(4.3±2.0, p=0.08). Average physical demand was greater for AI for MTHA(6±1.3) than RATHA(3.7±2.1, p=0.29). Average mental demand was significantly greater during AR for MTHA(5.7±1.03) when compared to RATHA(3.2±1.5, p=0.007). Average mental demand was greater during AI for MTHA(6.2±1.2) than RATHA(2.3±1.5, p=0.051). Conclusion. Regardless of prior surgical experience, both surgeons had reduced caloric expenditure when performing RATHA as compared to MTHA. For the surgeon with more RATHA experience, there was a greater percent reduction in caloric expenditure between surgical interventions. Both surgeons had similar percent reductions in time for RATHA compared to MTHA. Each surgeon noted increased mental and physical demand during MTHA. The trends suggest RATHA may reduce surgeon energy expenditure and time to perform acetabular reaming and implant insertion for THA. The pilot data suggests that there may be a relationship between energy expenditure and surgeon experience. This could be explored in future studies with a larger surgeon population. For any figures or tables, please contact the authors directly

Introduction:. The robot-assisted cementless total hip arthroplasty has theoretical advantages of providing better fit and mechanical stability of the stem. However, no previous study has been reported on a short stem implantation using surgical robot. We compared early clinical and radiographic results between robotic milling and manual rasping in short stem total hip arthroplasty. Materials & Methods:. We designed a prospective randomized controlled trial to determine whether robot-assisted short stem total hip arthroplasty improves the implant position represented by stem alignment, leg length equality, and reduces the intraoperative and early postoperative complications. A total of 40 patients were enrolled with informed consents and randomly assigned to robotic milling group (20 hips) and manual rasping group (20 hips) by means of a computer-generated random number table. There were no statistically significant differences in the demographics of the patients between the two groups. Results:. Total operation time of the robotic milling group was significantly longer than that of the manual rasping group (p = 0.015) with average 8.8 minutes registration time and average 11.1 minutes milling time. There was no significantly difference in total blood loss between the two groups. The robotic milling group showed superior results on stem alignment and leg length equality compared with the manual rasping group. Only in the manual rasping group, there were 2 intraoperative femoral fractures. No complications such as infection, nerve palsy or dislocation encountered in both groups. Conclusions:. Robotic-assisted short stem total hip arthroplasty has advantages in increased accuracy of stem alignment and leg length equality, and also helps reduce the potential risk of intraoperative femoral fracture

While total knee arthroplasty has demonstrated clinical success, final bone cut and final component alignment can be critical for achieving a desired overall limb alignment. This cadaver study investigated whether robotic-arm assisted total knee arthroplasty (RATKA) allows for accurate bone cuts and component position to plan compared to manual technique. Six cadaveric specimens (12 knees) were prepared by an experienced user of manual total knee arthroplasty (MTKA), who was inexperienced in RATKA. For each cadaveric pair, a RATKA was prepared on the right leg and a MTKA was prepared on the left leg. Final bone cuts and final component position to plan were measured relative to fiducials, and mean and standard deviations were compared. Measurements of final bone cut error for each cut show that RATKA had greater accuracy and precision to plan for femoral anterior internal/external (0.8±0.5° vs. 2.7±1.9°) and flexion/extension* (0.5±0.4° vs. 4.3±2.3°), anterior chamfer varus/valgus* (0.5±0.1° vs. 4.1±2.2°) and flexion/extension (0.3±0.2° vs. 1.9±1.0°), distal varus/valgus (0.5±0.3° vs. 2.5±1.6°) and flexion/extension (0.8±0.5° vs. 1.1±1.1°), posterior chamfer varus/valgus* (1.3±0.4° vs. 2.8±2.0°) and flexion/extension (0.8±0.5° vs. 1.4±1.6°), posterior internal/external* (1.1±0.6° vs. 2.8±1.6°) and flexion/extension (0.7±0.6° vs. 3.7±4.0°), and tibial varus/valgus* (0.6±0.3° vs. 1.3±0.7°) rotations, compared to MTKA, respectively, (where * indicates a significant difference between the two operative methods based on 2- Variances testing, with α at 0.05). Measurements of final component position error show that RATKA had greater accuracy and precision to plan for femoral varus/valgus* (0.6±0.3° vs. 3.0±1.4°), flexion/extension* (0.6±0.5° vs. 3.0±2.1°), internal/external (0.8±0.5° vs. 2.6±1.6°), and tibial varus/valgus (0.7±0.4° vs. 1.1±0.8°) than the MTKA control, respectively. In general, RATKA demonstrated greater accuracy and precision of bone cuts and component placement to plan, compared to MTKA in this cadaveric study. For further confirmation, RATKA accuracy of component placement should be investigated in a clinical setting

Introduction. While manual total knee arthroplasty (MTKA) procedures have demonstrated excellent clinical success, occasionally intraoperative damage to soft tissues can occur. Robotic-arm assisted technology is designed to constrain a sawblade in a haptic zone to help ensure that only the desired bone cuts are made. The objective of this cadaver study was to quantify the extent of soft tissue damage sustained during TKA through a robotic-arm assisted (RATKA) haptically guided approach and conventional MTKA approach. Methods. Four surgeons each prepared six cadaveric legs for CR TKA: 3 MTKA and 3 RATKA, for a total of 12 RATKA and 12 MTKA knees. With the assistance of an arthroscope, two independent surgeons graded the damage of 14 knee structures: dMCL, sMCL, posterior oblique ligament (POL), semi-membranosus muscle tendon (SMT), gastrocnemius muscle medial head (GMM), PCL, ITB, lateral retinacular (LR), LCL, popliteus tendon, gastrocnemius muscle lateral head (GML), patellar ligament, quadriceps tendon (QT), and extensor mechanism (EM). Damage was defined as tissue fibers that were visibly torn, cut, frayed, or macerated. Percent damage was averaged between evaluators, and grades were assigned: Grade 1) complete soft tissue preservation to ≤5% damage; Grade 2) 6 to 25% damage; Grade 3) 26 to 75% damage; and Grade 4) 76 to 100% damage. A Wilcoxon Signed Rank Test was used for statistical comparisons. A p-value <0.05 was considered statistically significant. Results. Significantly less damage occurred to the PCL in the RATKA than the MTKA specimens (p=0.004). RATKA specimens had less damage to the dMCL (p=0.186), ITB (p=0.5), popliteus (p=0.137), and patellar ligament (p=0.5). The sMCL, POL, SMT, GMM, GML, LR, LCL, QT, and EM were grade 1 in all MTKA and RATKA specimens. No intentional soft tissue releases were performed in either group to balance the knee. Discussion/Conclusion. The results of this study indicate that RATKA may result in less soft-tissue damage than MTKA, especially to the posterior cruciate ligament. This finding can potentially be attributed to RATKA using a haptic boundary to constrain the sawblade, which can help prevent unwanted soft-tissue damage. However, since any damage was post-operatively assessed and in a cadaveric model, further investigations on soft-tissue damage from patients with clinical outcomes should be performed

Introduction. The success of total knee arthroplasty depends on many factors, including the preoperative condition of the patient, the design and materials of the components and surgical techniques. It is important to position the femoral and tibial components accurately and to balance the soft tissues. Malpositioning of the component can lead to failures due to aseptic loosening, instability, polyethylene wear and dislocation of the patella. In order to improve post-operative alignment, computer-aid systems have been developed for total knee arthroplasty. Many clinical and experimental studies of these systems have shown that the accuracy of implanted components can be improved in spite of the increase in costs and operating time. This may not, however, improve the outcome in the short-term. Restoration of the normal mechanical axis of the knee and balancing of the surrounding soft tissues have been shown to have an important bearing on the final outcome of knee replacement operations. In severely deformed knees, whether varus or valgus, these goals may be difficult to achieve. We compared the radiologic results of the mechanical axis and implant position of Total Knee Arthroplasty using a robot-assisted method with conventional manually implanted method in severe varus deformed knee. Materials and Methods. A data set of 50 consecutive cases that were performed from April 2007 to December 2010 using the robot assisted TKA(Group A) were compared with a data set of 50 consecutive cases from the same period that were done using conventional manual TKA(Group B). All cases had a preoperative mechanical varus deformity >15° and one brand of implant was used on all cases. The diagnosis was primary osteoarthritis in all knees. The operations were performed by one-senior author with the same robot system, ROBODOC (ISS Inc., CA, USA) along with the ORTHODOC (ISS Inc., CA, USA) planning computer. (See Figure 1.) The radiological evaluations included mechanical axis, implant position (α,β,γ,δ angle) according to the system of American Knee Society. Results. There was a significant difference in the postoperative α, β, γ angle and mechanical axis between two group(p<0.05). In group A, mechanical axis angle changed from preoperative varus 18.5±3.3° to postoperative varus 0.6±1.5° without outlier. In group B, mechanical axis angle changed from varus 19.4±4.2° to varus 2.5±3.8° with 8 outliers. In group A, the mean α, β, γ, δ angle were 96.7°, 90.1°, 1.9°, 86.8° and 93.1°, 88.3°, 3.8°, 85.9° in group B. But we found no loosening and osteolysis at last follow up in both group. Conclusion. On the basis of our results, patients with severe varus knee(>15°) tended to have more postoperative varus mechanical alignment in conventional manual TKA group than robot-assisted TKA group. We think that robot-assisted TKA is helpful in excessive varus knee in aspect of not only mechanical alignment and implant position but also long term clinical results and implant longevity. However, a long term followup evaluation will be necessary and complications in robot system

Background:. Coronal malalignment occurs frequently in total knee arthroplasty (TKA) and reduces implant longevity and function. Designed to improve consistency and efficiency, patient- specific positioning guides (PSPG) generated from preoperative imaging studies represent a paradigm shift from manual instrumentation (MI) and intraoperative computer navigation. Purposes:. We compare the efficacy of PSPG to MI in (1) restoring mechanical axis of the extremity and (2) achieving neutral alignment of the femoral and tibial components. Methods:. We retrospectively examined 696 postoperative anteroposterior standing long-leg radiographs after TKA (545 PSPG, 151 MI) by two surgeons. Coronal alignment was assessed by determining the zone in which the overall mechanical axis (OMA) passed through the knee, measuring the hip-knee-ankle (HKA) angle between the tibial and femoral mechanical axes, and finally, noting the alignment of the femoral and tibial components with respect to their mechanical axes. Results:. The OMA passed through the central third more frequently with PSPG than MI for both surgeons (JHD: 86.6% vs. 77%, p = 0.02; AVL: 86.4% vs. 74.5%, p = 0.11). For the senior author, while percent of HKA outliers >3ï,° was similar between PSPG and MI, the mean error from neutral for these patients was significantly less with PSPG than MI (4.50ï,° vs. 5.25ï,°, p = 0.0031). The tibial component demonstrated no significant difference between PSPG and MI. With PSPG, average individual deviation from neutral for the femoral component was significantly less (0.91ï,° vs. 1.34ï,°, p = 0.0005) and had fewer outliers >2ï,° (4.9% vs. 19.6%, p = 0.017). Discussion:. Improved coronal alignment in total knee arthroplasty (TKA) is associated with greater patient satisfaction, better functional scores and increased implant longevity [11,30,31,36]. Recently, preoperative three-dimensional imaging and custom manufacturing have enabled the development of patient-specific positioning guides (PSPG). Designed to improve consistency and efficiency, PSPG represents a paradigm shift away from intramedullary and extramedullary guides, or manual instrumentation (MI), and an evolution from intraoperative computer-assisted navigation (CAN). Even in the hands of experienced surgeons, MI frequently results in significant component angulation and mechanical axis malalignment [32]. Multiple studies support the restoration of a neutral axis as a critical factor in implant performance and potential longevity of total knee arthroplasty [2, 3, 5, 18, 41, 44]. Intraoperative CAN has been shown to improve precision and accuracy of alignment compared to MI with a reduction in the number of outliers (less than 3ï,° varus/valgus) [32, 38] and the amount of blood loss [39], but is hindered by time-consuming landmark registration, increased operative length [7], greater cost, the risk for stress fracture, pin loosening, and a substantial learning curve [6, 22, 29, 43]. Patient-specific positioning guides, on the other hand, purportedly eliminate many of the disadvantages of CAN while still allowing the bone resections to match the measured overall mechanical axis. While accurate and precise alignment guides are potent tools in restoring the proper overall mechanical axis, they are not a substitute for careful preoperative planning, good clinical and intraoperative judgment, appropriate soft tissue balancing, and precise implantation technique. Nevertheless, patient-specific positioning guides can provide the first step in the right direction to a successful TKA. Conclusions:. Patient-specific positioning guides can assist in restoration of the mechanical axis with reduction in outliers. Level of Evidence: Level III, retrospective case-control study

Metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been a popular alternative treatment for young patients with hip osteoarthritis. Despite its advantages over total hip arthroplasty, the use of MoMHRA remains controversial. Achieving the correct positioning of the prosthetic is a concern due to the difficulty and novelty of this procedure. Furthermore, it has been reported that post-operative management using 2D radiographs contains high degrees of variance leading to poor detection of prosthetic malpositioning. In order to compensate for the lack of available technology, current literature has suggested the use of blood metal ion levels as indirect predictors of prosthetic malpositioning due to the abnormal release of metal ions, particularly Chromium and Cobalt, as a result of increase wear and tear. The purpose of this study was to determine whether 2D/3D registration technology can report prosthetic orientation in vivo and, to establish whether 3D technology can accurately deduce prosthetic wear by correlating prosthetic angles with metal ion counts. To begin this study, post-operative x-rays (n=72) were used as the two-dimensional media to measure acetabular orientation. Only the acetabular component was examined in this study and acetabular orientation was defined as the function of inclination and version angles. Virtual three-dimensional models of the native, pre-operative pelvises and the acetabular implant were generated and were manually superimposed over the post-operative x-ray images according to anatomical landmarks. A manual 2D/3D registration program was specifically designed for this task. Inclination and version angles of the 2D/3D registered product were measured. Post-operative CT models, which offer the most accurate depiction of the prosthetic in vivo, were generated for validation. Contrary to the study's hypotheses and current literature, no significant difference was observed between 2D vs. 2D/3D vs. CT data, suggesting that 2D and 2D/3D measurements were similar to the results of the gold standard CT model (although 2D/3D measurements were more precise compared to 2D media). Furthermore, statistical analyses revealed no significant correlation in either 2D or 2D/3D compared to metal ion levels, although a stronger trend was demonstrated using 2D/3D measurements. These results are suggestive that 2D/3D registered measurements are equivocal to those using the conventional 2D x-ray and, manual 2D/3D registered measurements do not demonstrate greater efficacy in predicting prosthetic wear. Moreover, the data from this study also revealed insignificant correlations between the angles of acetabular orientation and metal ion release. Combined angles within and beyond the acceptable ranges for inclination (30°–50°) and version (5°–20°) angles did not produce significant trends with metal ion release. These results lead to the paradoxical conclusion that acetabular orientation does not influence prosthetic wear. The findings of this study are inconsistent with the reports in current literature and further investigation is required

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

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

The robotic-assisted system (ROBODOC) is the first active robot that was designed to reduce potential human errors in performing cementless total hip arthroplasty (THA). We have reported minimum five years follow-up clinical results. However, to our knowledge, there have been no longer follow-up reports. The purpose of this study was to prospectively compare the minimum ten years follow-up results of robotic-assisted and hand-rasping stem implantation techniques.

Between 2000 and 2002, we performed 146 THA on 130 patients who were undergoing primary THA. Robot assisted primary THA was performed on 75 hips and a hand-rasping technique was used on 71 hips. Among them, 112 hips (53 hips in the robotic milling group and 59 hips in the hand-rasping group) were followed more than 10 years. Follow-up periods ranged from 120–152 months (average 135). Preoperatively, we plan the position and the size of the stem three-dimensionally for both groups. At the operation, posterolateral approach was used. We evaluated survivorship and compared clinical results.

At the final follow-up, no stem was revised in either group. Plain radiographs showed bone ingrowth fixation for all the stems of both groups. There were no signs of mechanical loosening in any implant. Preoperatively, there were no significant differences in the Japanese Orthopedic Association (JOA) hip scores between the two groups. Ten years postoperatively, it was significantly better in the robotic milling group (98 points and 96 points, respectively) (Mann-Whitney U-test; p<0.05). The main difference was observed in the category of range of motion (19 points and 18 points, respectively) (p=0.01).

In the previous study, we have reported that the JOA hip score was significantly better in the robotic milling group up to three years postoperatively. In the present study, we found that it was still significantly better at ten years postoperatively. In conclusion, robotic milling THA was associated with better clinical scores until ten years postoperatively.

Most cost containment efforts in public health systems have focused on regulating the use of hospital resources, especially operative time. As such, attempting to maximize the efficiency of limited operative time is important. Typically, hospital operating room (OR) scheduling of time is performed in two tiers: 1) master surgical scheduling (annual allocation of time between surgical services and surgeons) and 2) daily scheduling (a surgeon's selection of cases per operative day). Master surgical scheduling is based on a hospital's annual case mix and depends on the annual throughput rate per case type. This throughput rate depends on the efficiency of surgeons’ daily scheduling. However, daily scheduling is predominantly performed manually, which requires that the human planner simultaneously reasons about unknowns such as case-specific length-of-surgery and variability while attempting to maximize throughput. This often leads to OR overtime and likely sub-optimal throughput rate. In contrast, scheduling using mathematical and optimization methods can produce maximum systems efficiency, and is extensively used in the business world. As such, the purpose of our study was to compare the efficiency of 1) manual and 2) optimized OR scheduling at an academic-affiliated community hospital representative of most North American centres. Historic OR data was collected over a four year period for seven surgeons. The actual scheduling, surgical duration, overtime and number of OR days were extracted. This data was first configured to represent the historic manual scheduling process. Following this, the data was then used as the input to an integer linear programming model with the goal of determining the minimum number of OR days to complete the same number of cases while not exceeding the historic overtime values. Parameters included the use of a different quantile for each case type's surgical duration in order to ensure a schedule within five percent of the historic overtime value per OR day. All surgeons saw a median 10% (range: 9.2% to 18.3%) reduction in the number of OR days needed to complete their annual case-load compared to their historical scheduling practices. Meanwhile, the OR overtime varied by a maximum of 5%. The daily OR configurations differed from historic configurations in 87% of cases. In addition, the number of configurations per surgeon was reduced from an average of six to four. Our study demonstrates a significant increase in OR throughput rate (10%) with no change in operative time required. This has considerable implications in terms of cost reduction, surgical wait lists and surgeon satisfaction. A limitation of this study was that the potential gains are based on the efficiency of the pre-existing manual scheduling at our hospital. However, given the range of scenarios tested, number of surgeons included and the similarity of our hospital size and configuration to the majority of North American hospitals with an orthopedic service, these results are generalizable. Further optimization may be achieved by taking into account factors that could predict case duration such as surgeon experience, patients characteristics, and institutional attributes via machine learning

Evaluation of patient specific spinopelvic mobility requires the detection of bony landmarks in lateral functional radiographs. Current manual landmarking methods are inefficient, and subjective. This study proposes a deep learning model to automate landmark detection and derivation of spinopelvic measurements (SPM). A deep learning model was developed using an international multicenter imaging database of 26,109 landmarked preoperative, and postoperative, lateral functional radiographs (HREC: Bellberry: 2020-08-764-A-2). Three functional positions were analysed: 1) standing, 2) contralateral step-up and 3) flexed seated. Landmarks were manually captured and independently verified by qualified engineers during pre-operative planning with additional assistance of 3D computed tomography derived landmarks. Pelvic tilt (PT), sacral slope (SS), and lumbar lordotic angle (LLA) were derived from the predicted landmark coordinates. Interobserver variability was explored in a pilot study, consisting of 9 qualified engineers, annotating three functional images, while blinded to additional 3D information. The dataset was subdivided into 70:20:10 for training, validation, and testing. The model produced a mean absolute error (MAE), for PT, SS, and LLA of 1.7°±3.1°, 3.4°±3.8°, 4.9°±4.5°, respectively. PT MAE values were dependent on functional position: standing 1.2°±1.3°, step 1.7°±4.0°, and seated 2.4°±3.3°, p< 0.001. The mean model prediction time was 0.7 seconds per image. The interobserver 95% confidence interval (CI) for engineer measured PT, SS and LLA (1.9°, 1.9°, 3.1°, respectively) was comparable to the MAE values generated by the model. The model MAE reported comparable performance to the gold standard when blinded to additional 3D information. LLA prediction produced the lowest SPM accuracy potentially due to error propagation from the SS and L1 landmarks. Reduced PT accuracy in step and seated functional positions may be attributed to an increased occlusion of the pubic-symphysis landmark. Our model shows excellent performance when compared against the current gold standard manual annotation process

Problem. The identification of unknown orthopaedic implants is a crucial step in the pre-operative planning for revision joint arthroplasty. Compatibility of implant components and instrumentation for implant removal is specific based on the manufacturer and model of the implant. The inability to identify an implant correctly can lead to increased case complexity, procedure time, procedure cost and bone loss for the patient. The number of revision joint arthroplasty cases worldwide and the number implants available on the market are growing rapidly, leading to greater difficulty in identifying unknown implants. Solution. The solution is a machine-learning based mobile platform which allows for instant identification of the manufacturer and model of any implant based only on the x-ray image. As more surgeons and implant representatives use the platform, the model should continue to improve in accuracy and number of implants recognized until the algorithm reaches its theoretical maximum of 99% accuracy. Market. Multiple organizations have created small libraries of implant images to assist surgeons with manual identification of unknown implants based on the x-ray, however no automated implant identification system exists to date. One of the most financially successful implant identification tools on the market is a textbook of hip implants which sells for a per unit cost of $200. Several free web-based resources also act as libraries for the manual identification of a limited number of arthroplasty implants. A number of academic and private organizations are working on the development of an automated system for implant identification, however none are available to the public. Product. Implant Identifier is mobile application which uses machine-learning to instantly detect the model and manufacturer of any common arthroplasty implant, based only on x-ray. The beta version offers a large library of implants for manual identification and is currently available for free download on iOS and Android. Its purpose is to further develop the model to its maximal theoretical accuracy, prior to official release. The beta version of the application currently has over 15,000 registered users worldwide and has the largest publicly available arthroplasty library available on the market. Over 200,000 implant images have been submitted by users to date. Timescales. The product was initially released in the form of a closed beta which became available to invited guests around 18 months ago. The current version is an open beta which can be downloaded and used by any individual. It was released roughly 12 months ago. The final rendition of the application will allow for free manual identification using the implant library, as well as subscription-based automated implant identification. The implementation, testing and release of this final subscription product is projected to be completed by Q3 2022. Funding. A small number of early investors have funded the initial research and development of the beta product; however, another round of investment will be beneficial in the final evolution of the product. This additional investment round will allow for completion of development of the identification algorithm, product dissemination, customer support, and lasting sustainability of the venture

Introduction. The use of technology, such as navigation and robotic systems, may improve the accuracy of component positioning in total hip arthroplasty (THA) but its impact on patient reported outcomes measures (PROMs) remains unclear. This study aims to identify the association between intraoperative use of technology and patient reported outcomes measures (PROMs) in patients who underwent primary total hip arthroplasty (THA). Methods. We retrospectively reviewed patients who underwent primary THA between 2016 and 2020 and answered a post-operative PROM questionnaire. Patients were separated into three groups depending on the technology utilized intraoperatively: navigation, robotics, or no technology (i.e. manual THA. The Forgotten Joint Score (FJS-12) and Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS, JR) were collected at various time points (FJS: 3m, 1y, and 2y; HOOS, JR: pre-operatively, 3m, and 1y). Demographic differences were assessed with chi-square and ANOVA. Mean scores between all groups were compared using univariate ANCOVA, controlling for observed demographic differences. Results. Of the 1,960 cases included, 896 navigation, 135 robotics, and 929 manual. There was a significant statistical difference in one-year HOOS, JR scores (85.23 vs. 85.95 vs. 86.76; p=0.014) and two-year FJS-12 scores (64.72 vs. 73.35 vs. 74.63; p=0.004) between the three groups. However, they did not exceed the mean clinically important difference (MCID) at any time period. Short and long-term PROMs significantly differed between navigation and manually performed cases (FJS 3m: p=0.047; FJS 2y: p=0.001; HOOS, JR 1y: p=0.004). Two-year FJS-12 scores statistically differed between navigation and robotics (p=0.038). There was no statistical difference in either FJS-12 or HOOS, JR scores between robotics and manual THA groups at all time points (FJS 3m:p=0.076, 1y:p=0.225, 2y:p=0.793; HOOS, JR preop:p=0.872, 3m:p=0.644, 1y:p=0.531). Conclusion. Statistical differences observed between all modalities are not likely to be clinically meaningful with regards to early patient reported outcomes. While intraoperative use of technology may improve the accuracy of implant placement, these modalities have not necessarily translated into improved early reported functional outcomes

Introduction. Several hexapod external fixator devices are used in the treatment of bone fracture and deformity corrections. One characteristic of all of them is the requirement for manual adjustment of the fixator struts. The purpose of this study was to introduce a novel robotic system that executes automatic adjustment of the struts. Materials and Methods. Ten patients were treated for various bone deformities using a hexapod external fixator with Auto Strut system, which implemented automatic adjustment of the fixator struts. Patients arrived at the clinic for follow during the correction period until the removal of the hardware. During each visit, the progress of the correction was assessed (clinically and radiographically) and reading of the strut scale numbers was performed. Results. All patients completed the treatment plan during the follow up period achieving all planned correction goals. Healing of the bone ranged between approximately one to seven months. Duration of distraction ranged between 10 and 90 days. The distraction index ranged between 8 and 15 days/cm. The length of distraction varied between 1 and 6 cm. The planned corrections were fully attained in all patients who completed the treatment (n=10). No device related adverse events were reported. One patient was not available for registration of struts length, one patient switched to manual struts due to personal preference.48 struts of eight patients were recorded, 94% of the final strut number readings presented a displacement of 0–1 mm, three struts (6%) had 2–3 mm displacement due to inter-observer reading errors. indicating high precision of the automatic adjustment. Conclusions. This study presents preliminary result, showing that Auto Strut can successfully replace the manual strut adjustment providing important advantages that benefit the patient, the caregiver and the surgeon