Robotic-assisted Total Hip Arthroplasty Research Articles

Cost-effectiveness of a novel, fluoroscopy-based robotic-assisted total hip arthroplasty system: A Markov analysis.

The purpose of this study was to assess the cost-effectiveness of a novel, fluoroscopy-based robotic-assisted total hip arthroplasty (RA-THA) system compared to a manual unassisted technique (mTHA) up to 5years post-operatively. A Markov model was constructed to compare the cost-effectiveness of RA-THA and mTHA. Cost-effectiveness was defined as an Incremental Cost-Effectiveness Ratio (ICER) <$50000 or $100000 per Quality Adjusted Life Year (QALY). RA-THA patients experienced lower costs compared to mTHA patients at 1year ($20865.12±9897.52 vs. $21660.86±9909.15; p<0.001) and 5years ($23124.57±10045.48 vs. $25756.42±10091.84; p<0.001) post-operatively. RA-THA patients also accrued more QALYs (1-year: 0.901±0.117 vs. 0.888±0.114; p<0.001; 5-years: 4.455±0.563 vs. 4.384±0.537 p<0.001). Overall, RA-THA was cost-effective (1-year ICER: $-61210.77; 5-year ICER: $-37068.31). The novel, fluoroscopy-based RA-THA system demonstrated cost-effectiveness when compared to manual unassisted THA.

Robotic-assisted total hip arthroplasty utilizing a fluoroscopy-guided system resulted in improved intra-operative efficiency relative to a computerized tomography-based platform.

Robotic-assisted total hip arthroplasty (THA) using a computerized-tomography (CT) based workflow increases surgical time relative to traditional manual technique. The purpose of this investigation was to compare the intra-operative efficiencies of two robotic THA systems: a fluoroscopy-based platform (FL-RTHA) and a contemporary, CT-based (CT-RTHA) platform. A review of 107 consecutive FL-RTHA and 159 CT-RTHA primary, direct anterior approach (DAA) THA procedures was conducted. All cases were performed by one of two surgeons operating at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Primary outcome variables included averages and consistencies (variances) for surgical times and operating room (OR) times. A secondary outcome was to quantify the duration of robot-active phases in the FL-RTHA workflow. The FL-RTHA cohort experienced shorter surgical times (38.71min ± 7.00 vs. 75.33min ± 11.38; p < 0.001) and OR times (101.35min ± 12.22 vs. 156.74min ± 17.79; p < 0.001) compared to the CT-RTHA cohort. Surgical times and OR times were both more consistent in the FL-RTHA cohort compared to the CT-RTHA cohort (p < 0.001). Patients who underwent DAA THA with the assistance of a fluoroscopy-based robotic system experienced shorter and more consistent surgical times and OR times compared to patients who underwent similar DAA THA procedures with a contemporary, CT-based robotic platform.

Preliminary study of short-term outcomes and learning curves of robotic-assisted THA: comparison between closed platform robotic system and open platform robotic system

BackgroundBoth closed platform and open platform robotic-assisted total hip arthroplasty (THA) have recently been recommended as a viable treatment option for achieving accurate positioning of components. Yet, limited studies paid attention to the differences between the closed platform robotic system and the open platform robotic system. Hence, this study aimed to investigate clinical outcomes, radiographic outcomes, complication rates and learning curve of two systems.Materials and methodsWe retrospectively included 62 patients (31 closed robotic system and 31 open robotic system) who underwent THA between February 2021 and January 2023. The demographics, operating time, cup positioning, complications and hip Harris score were evaluated. Learning curves of operation time was conducted using cumulative sum (CUSUM) analysis.ResultsThere were no differences in surgical time (76.7 ± 12.1 min vs. 72.3 ± 14.8 min), estimated blood loss (223.2 ± 13.2 ml vs. 216.9 ± 17 ml) and Harris Hip score (HHS) between closed platform robotic system and the open platform robotic system. The closed robotic system and the open robotic system were associated with a learning curve of 9 cases and 7 cases for surgical time respectively, based on the satisfying rate of Lewinnek’s safe zone outliers (1/31, 96.8%) and no occurrence of complication. Both robotic systems had significant reduction in overall surgical time, the duration of acetabulum registration, and estimated blood loss between learning phase and proficiency phase.ConclusionThe authors suggest that the surgical outcomes and safe zone outlier rate of the open robotic-assisted THA were similar to those of the closed robotic-assisted THA. These two robotic-assisted are associated with comparable learning curves and both have the precise positioning of acetabular component. From learning phase to proficiency phase, the rate of positions within the safe zone differed only marginally (88.9–100% vs. 85.7–100%) based on a rather low number of patients. This is not a statistically significant difference. Therefore, we suggest that THA undergoing with the robotic-assisted system is the relatively useful way to achieve planned acetabular cup position so far.

Improved short-term outcomes for a novel, fluoroscopy-based robotic-assisted total hip arthroplasty system compared to manual technique with fluoroscopic assistance.

While robotic-assisted total hip arthroplasty (RA-THA) has been associated with improved accuracy of component placement, the perioperative and early postoperative outcomes of fluoroscopy-based RA-THA systems have yet to be elucidated. This retrospective cohort analysis included a consecutive series of patients who received manual, fluoroscopy-assisted THA (mTHA) and fluoroscopy-based RA-THA at a single institution. We compared rates of complications within 90days of surgery, length of hospital stay (LOS), and visual analog scale (VAS) pain scores. No differences existed between groups with respect to demographic data or perioperative recovery protocols. The RA-THA cohort had a significantly greater proportion of outpatient surgeries compared to the mTHA cohort (37.4% vs. 3.8%; p < 0.001) and significantly lower LOS (26.0 vs. 39.5h; p < 0.001). The RA-THA cohort had a smaller 90-day postoperative complication rate compared to the mTHA cohort (0.9% vs. 6.7%; p = 0.029). The RA-THA cohort had significantly lower patient-reported VAS pain scores at 2-week follow-up visits (2.5 vs. 3.3; p = 0.048), but no difference was seen after 6-week follow visits (2.5 vs. 2.8; p = 0.468). Fluoroscopy-based RA-THA demonstrates low rates of postoperative complications, improved postoperative pain profiles, and shortened LOS when compared to manual, fluoroscopy-assisted THA.

Correcting Hip Dysplasia in Young Adults: Intraoperative Navigation and Outcomes.

Developmental dysplasia of the hip (DDH) often leads to characteristic acetabular dysplasia and typical femoral anomalies. There are numerous treatments for skeletally mature patients with DDH including hip arthroscopy, pelvic and femoral osteotomies, as well as total hip arthroplasty. Before proceeding to an arthroplasty procedure, it can be helpful to obtain an opinion of a hip preservation specialist to ascertain if alternative surgical treatments could contribute to the patient's care. In general, the use of robotic navigation has been associated with a higher proportion of cups placed in the Lewinnek safe zone, larger improvements in Harris Hip Scores, and no difference in overall complication rates in comparison to manual total hip arthroplasty. The use of robotic navigation allows for both 2-dimensional and 3-dimensional preoperative templating, enabling the surgeon to plan the position of the construct such that it achieves maximum bony purchase and hip stability. In complex DDH cases, surgeons can work with a biomechanics department to complete a fit check assessment, which utilizes 3-dimensional templating software to ascertain the appropriateness of the implant's geometry with the patient's anatomy. Furthermore, a 3-dimensional printed plastic model of the pelvis and/or femur can be constructed in order to complete a rehearsal procedure, which may be particularly helpful for those cases involving osteotomies. The literature on the use of robotic-assisted total hip arthroplasty in patients with DDH demonstrates improved component positioning in comparison to navigated as well as manual methods; however, studies with long-term follow-up in this patient population are lacking.

Perioperative safety and efficacy of robot-assisted total hip arthroplasty in ERAS-managed patients: a pilot study

AimsRobot-assisted total hip arthroplasty (rTHA) boasts superior accuracy in implant placement, but there is a lack of effective assessment in perioperative management in the context of enhanced recovery after surgery (ERAS). This study aimed to compare the effectiveness and safety of rTHA versus conventional total hip arthroplasty (cTHA) in ERAS-managed patients.MethodsIn this prospective trial, a total of 60 eligible patients aged between 18 and 80 years were randomly divided into two groups to undergo either rTHA or cTHA. The primary outcomes included blood loss parameters. Secondary outcomes were the duration of the operation, surgical time, WOMAC pain score, WOMAC stiffness score, WOMAC physical function score, Harris score, and postoperative complications.ResultsThe study cohort analyzed 59 eligible participants, 30 of whom underwent rTHA and 29 of whom underwent cTHA. Analysis could not be conducted for one patient due to severe anemia. Notably, the cTHA group had a significantly shorter surgical time than the rTHA group (69.49 ± 18.97 vs. 104.20 ± 19.63 min, P < 0.001). No significant differences were observed between the rTHA and cTHA groups for blood loss parameters, including total blood loss (1280.30 ± 404.01 vs. 1094.86 ± 494.39 ml, P = 0.137) and drainage volume (154.35 ± 121.50 vs. 159.13 ± 135.04 ml, P = 0.900), as well as intraoperative blood loss (126.67 ± 38.80 vs. 118.52 ± 60.68 ml, P = 0.544) and hidden blood loss (982.43 ± 438.83 vs. 784.00 ± 580.96 ml, P = 0.206). Only one patient in the cTHA group required allogeneic blood transfusion. At 3 months postoperatively, both groups showed improvements in WOMAC pain score, WOMAC stiffness score, WOMAC physical function score, and Harris score, with no significant differences found between the two groups. Few complications were reported in both groups without significant differences.ConclusionsDespite the longer surgical time, rTHA did not negatively affect blood loss, pain, or functional recovery or lead to an increased risk of complications in ERAS-managed patients, suggesting that rTHA can be safely and effectively incorporated into an ERAS program for primary THA.

A review of robotic-assisted total hip arthroplasty.

Total hip arthroplasty (THA) is a successful surgical method for hip replacement but still poses challenges and risks. Robotic-assisted THA (rTHA) using new generation robotic systems has emerged to improve surgical precision and outcomes. The purpose of this paper is to review the literature on rTHA, with a focus on its advantages, such as individualized preoperative planning, intraoperative assistance, and improved accuracy in implantation, especially in complex cases. Additionally, it aims to explore the disadvantages associated with the use of rTHA, including high costs, the learning curve, and prolonged operation time compared to manual THA (mTHA), which are critical drawbacks that require careful consideration and efforts for minimization. Some financial analyses suggest that rTHA may offer cost-effectiveness and reduced postoperative costs compared to mTHA. While technological advancements are expected to reduce technical complications, there are still debates surrounding long-term outcomes. Practical limitations, such as limited availability and accessibility, also warrant attention. Although the development of rTHA shows promise, it is still in its early stages, necessitating critical evaluation and further research to ensure optimal patient benefits.

Simulating movements of daily living in robot-assisted total hip arthroplasty with 3D modelling.

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. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events.

Improved accuracy of a novel fluoroscopy-based robotically assisted THA system compared to manual THA.

Accurate acetabular cup position remains a persistent challenge in total hip arthroplasty (THA). Studies investigating the early outcomes of robotic-assisted THA (RA-THA) systems have shown improved cup placement compared to manual THA (mTHA) approaches, however, contemporary robotic platforms are reliant on pre-operative CT imaging. The goal of this study was to analyze the accuracy of a novel, fluoroscopy-based RA-THA system compared to an unassisted mTHA approach and determine the effect of the robotic system on operative time. We performed a retrospective cohort analysis on a consecutive series of 198 patients who received mTHA and RA-THA between March 2021 and July 2022. The primary outcome of interest was the accuracy of acetabular component placement, defined by average cup inclination and anteversion. Secondary outcomes included the proportion of acetabular cups positioned within the Lewinnek safe zone, operative time, and overall room time. The RA-THA group demonstrated significantly higher accuracy of acetabular anteversion to target compared to the manual group (18.5 vs. 21.7˚; p < 0.001), and had a significantly greater proportion of acetabular cups placed within the Lewinnek safe zone (81.6 vs. 59.0%; p < 0.001). The RA-THA cohort had longer operative times compared to mTHA group (39.0 vs. 35.3min; p = 0.003), but no difference was seen in total operating room time (101.2 vs. 101.2min; p = 0.982). This study demonstrates that the use of a novel, fluoroscopy-based, pin-less THA robotic platform increased the accuracy of acetabular cup placement, including a 22.6% improvement in safe zone placement, compared to mTHA approach, with no increase in overall case time.

Acetabular cup placement and offset control in robotic total hip arthroplasty performed through the modified anterolateral approach.

The modified anterolateral approach (Röttinger) for total hip arthroplasty (THA) offers great advantages over conventional approaches, especially concerning early postoperative symptoms, which are mild and well tolerated by patients. Robotic-assisted implantation might facilitate rapid adoption of the modified anterolateral approach without exposing surgeons to risks encountered during the learning curve. This study posits that the use of robotic assistance in conjunction with the modified anterolateral approach for total hip arthroplasty (THA) can provide a substantial enhancement in the accuracy of cup placement in comparison to manual surgery. Thirty-two robotic-assisted THAs met the inclusion criteria and were matched to 32 conventional cases. Acetabular cup inclination, anteversion, limb-length discrepancy, and acetabular offset were assessed using certified planning software by two independent observers using pre- and postoperative anterior-posterior radiographs. Data was analyzed for normal distribution. Chi2 test was used to determine whether implanted acetabular cups that were within Lewinnek's safe zones were influenced by type of implantation. Effect size estimates and statistical power analysis were also performed to appreciate the appropriateness of the chosen sample size. Robotic-assisted implantation was found to significantly improve acetabular cup placement in terms of inclination (p < 0.001) but not anteversion (p = 0.783). Although mean postoperative limb-length discrepancy and mean acetabular offset did not differ between groups, a significantly smaller variance was found in the robotic-assisted group (p < 0.001) and (p = 0.04), respectively. There were no significant differences between the two groups in terms of consistently implanting the acetabular cup within the Lewinnek safe zones p = 0.641 for anteversion and p = 0.230 for inclination, respectively. Our results show that although robotic-assisted acetabular cup implantation performed through the modified anterolateral approach did not significantly differ from conventional implantation, it did offer increased accuracy in cup positioning, acetabular bone preservation, and limb-length restoration.

The learning curve for a novel, fluoroscopy-based robotic-assisted total hip arthroplasty system.

Adoption of robotic-assisted total hip arthroplasty (RA-THA) systems can improve the accuracy of acetabular cup placement, but no group has reported the learning curve of novel, fluoroscopy-based RA-THA systems. A learning-curve cumulative summation (LC-CUSUM) analysis was performed on a consecutive series of the first 100 patients who received fluoroscopy-based RA-THA by the study surgeon. Operative times and specific robotic timepoints were compared between learning and proficiency phases. Implementation of fluoroscopy-based RA-THA was associated with a learning curve of 12 cases. A 6-min increase in operative time was seen during the learning phase compared to the proficiency phase (44.3±4.4 vs. 38.0±7.1min; p<0.001), with a 3-min longer robotic cup impaction sequence during the learning phase (7.8±1.9 vs. 4.8±1.3min; p<0.001). Adoption of fluoroscopy-based RA-THA is associated with a brief learning curve of 12 cases, with the most significant improvements in surgical efficiency realised during acetabular cup placement.

Precise acetabular positioning, discrepancy in leg length, and hip offset using a new seven-axis robot-assisted total hip arthroplasty system requires no learning curve: a retrospective study

ObjectiveThe purpose of the present study was to determine the learning curve for a novel seven-axis robot-assisted total hip arthroplasty (RA-THA) system, and to explore whether it was able to provide greater accuracy in acetabular cup positioning, superior leg length discrepancy (LLD), and hip offset than conventional methods.MethodsA total of 160 patients in which unilateral THA was performed in the second affiliated Hospital of Xi'an Jiaotong University from July 2021 to September 2022 were studied. The first 80 patients underwent robot-assisted THA, while conventional THA was performed on the subsequent 80 by the same team of experienced surgeons. The learning curve for the RA-THA system was evaluated using cumulative sum (CUSUM) analysis. The demographic data, preoperative clinical data, duration of surgery, postoperative Harris hip score (HHS) and postoperative radiographic data from patients that had conventional THA were compared.ResultsThe 80 patients who underwent primary unilateral RA-THA comprised 42 males and 38 females and were followed up for 12 weeks. Using analysis by CUSUM, the learning curve of the RA-THA system could be divided into learning and proficiency phases, the former of which consisted of the first 17 cases. There was no significant difference between the learning and proficiency phases in terms of LLD, hip offset, or accuracy of acetabular prosthesis position in the RA-THA groups. The proportion of acetabular prostheses located in the Lewinnek safe zone was 90.5% in the proficiency group and 77.5% in the conventional group, respectively, a difference that was statistically significant (P < 0.05). The absolute error between target angle and postoperative measured angle of anteversion was statistically significant in the proficiency group and the conventional group((P < 0.05). Postoperative acetabular anteversion and LLD were 19.96 ± 5.68° and 6.00 (5.00) mm in the proficiency group, respectively, and 17.84 ± 6.81° and 8.09 (4.33) mm using conventional surgery, respectively (anteversion: P = 0.049; LLD: P < 0.001).ConclusionsThe surgical team required a learning curve of 17 cases using the RA-THA system to become proficient. There was no learning curve for other parameters, namely LLD, hip offset, or accuracy of acetabular prosthesis positioning. During the proficiency phase, the RA system was superior to conventional THA for control of leg length and accuracy of acetabular cup placement.

CT required to perform robotic-assisted total hip arthroplasty can identify previously undiagnosed osteoporosis and guide femoral fixation strategy

Osteoporosis can determine surgical strategy for total hip arthroplasty (THA), and perioperative fracture risk. The aims of this study were to use hip CT to measure femoral bone mineral density (BMD) using CT X-ray absorptiometry (CTXA), determine if systematic evaluation of preoperative femoral BMD with CTXA would improve identification of osteopenia and osteoporosis compared with available preoperative dual-energy X-ray absorptiometry (DXA) analysis, and determine if improved recognition of low BMD would affect the use of cemented stem fixation. Retrospective chart review of a single-surgeon database identified 78 patients with CTXA performed prior to robotic-assisted THA (raTHA) (Group 1). Group 1 was age- and sex-matched to 78 raTHAs that had a preoperative hip CT but did not have CTXA analysis (Group 2). Clinical demographics, femoral fixation method, CTXA, and DXA data were recorded. Demographic data were similar for both groups. Preoperative femoral BMD was available for 100% of Group 1 patients (CTXA) and 43.6% of Group 2 patients (DXA). CTXA analysis for all Group 1 patients preoperatively identified 13 osteopenic and eight osteoporotic patients for whom there were no available preoperative DXA data. Cemented stem fixation was used with higher frequency in Group 1 versus Group 2 (28.2% vs 14.3%, respectively; p = 0.030), and in all cases where osteoporosis was diagnosed, irrespective of technique (DXA or CTXA). Preoperative hip CT scans which are routinely obtained prior to raTHA can determine bone health, and thus guide femoral fixation strategy. Systematic preoperative evaluation with CTXA resulted in increased recognition of osteopenia and osteoporosis, and contributed to increased use of cemented femoral fixation compared with routine clinical care; in this small study, however, it did not impact short-term periprosthetic fracture risk.

PROMs in Total Hip Arthroplasty: A Comparison between Robotic Mako Assisted Versus Manual Technique

Study Purpose: The purpose of this observational study is to evaluate the degree of satisfaction and improvement in quality of life through PROMs (Patient Related Outcome Measures), which were administered to patients who underwent Total Hip Arthroplasty (THA) by robotic-arm assisted technique (RIO®, MAKO Surgical Corporation). These data were then compared to a sample of patients operated on by standard manual technique. Both groups were operated on by the same surgical team, in the same hospital, and were subjected to the same recommendation and rehabilitation protocols. Surgeries were performed from November 2017 to March 2019 at a hospital in Asl Toscana Sudest. Endpoint of our study is to verify the rate of improvement – which is assumed to be stable one year after surgery – and how the satisfaction rate increases over time. Another aim is to determine – through the use of Forgotten Joint Score questionnaires and the satisfaction scale – whether there is a difference between arthroplasty operated on by standard manual technique vs robotic-assisted method one year after surgery. Method: Patients who undergone robotic-assisted surgery were evaluated before surgery, at discharge, 1, 4 and 12 months after surgery. 70 robotic-assisted THA patients were studied for a whole year, while 31 standard-technique THA patients were evaluated only 12 months after surgery. PROMs post-surgical evaluations occurred during follow-up visits by orthopedists and physiotherapists. Harris Hip Score (HHs), Oxford Hip score (OHS), EQol VAS (Dimension Visual Analogue Scale), LiKert satisfaction scales were used. Likert scale was administered only 4 and 12 months after (no significant results before this time). The Forgotten Joint Scale (FJS) and the satisfaction scale were administered 1 year after surgery both in robotic-assisted and standard manual THA patients (70 robotic-assisted THA vs 31 standard THA). They were operated on in the same period by the same surgical team, with the presence of a senior surgeon, and were subjected to the same rehabilitation protocols by the same team of physiotherapists.Results: 70 robotic-assisted THA were analyzed (30 l, 40r), with a mean age of 63, 76 years. The average hospital stay in acute care settings was 3.07 days. 40 patients then continued in the rehabilitation department after discharge for further 2.98 days. HHs scale gave a value of 54, 94±14, 71 before surgery and 98, 63±2, 54 one year after surgery. OHS scale reported a value of 21, 27±9, 24 before surgery and 47±2, 06 one year after surgery. The EqolVas scale had a value of 56, 23±20, 04 before surgery and 81, 25±15, 84 one year after. 4 months after surgery, the satisfaction rate was 4, 67±0, 61 and 12 months later was 4, 77±0, 54. The FJS scale in 70 robotic-operated patients had a value of 86, 24±21, 1 and it has been compared to a group of 31 standard-operated patients, whose values were 87, 02±16, 57 and P=0,86. 12 months after surgery, the satisfaction rate for robotic-operated patients was 4, 77±0, 54 and 4, 47±0, 83 and P&lt;0, 05 for standard-operated patients, thus statistically significant. Conclusion: Patients undergoing hip arthroplasty surgery all have a high level of expectations and clinical outcomes are very satisfactory, while knee replacements have more limitations and less appreciable results. Some studies regarding THA report more favorable short-to-medium-term outcomes, fewer transfusions, and fewer days of hospital stay by the use of the roboticassisted technique, when compared to the standard manual surgery. Differences in function and quality of life after 1 year from the two types of surgery tend to decrease, although in our study the satisfaction rate of the robotic-assisted surgeries was statistically significant compared to the standard manual technique. Furthermore, it has been noticed that the rate of functional improvement, well-being, satisfaction and quality of life increases over time after surgery. At the first year of follow-up, no statistically significant differences are shown between the robotic-assisted and standard sample concerning the FJS scale.

Does acetabular robotic-assisted total hip arthroplasty with femoral navigation improve clinical outcomes at 1-year post-operative? A case-matched propensity score study comparing 98 robotic-assisted versus 98 manual implantation hip arthroplasties

IntroductionDespite the optimization of implant positioning, the clinical benefit of the use of robotic assistance during THA remains uncertain. In this case-control study (robotic versus manual technique) we made a retrospective short-term comparison of: (1) the functional results, (2) the complications, (3) and the influence of radiological symmetrization of the hips on the functional result. HypothesisThe use of a robotic arm improved the functional results of a THA. Materials and methodA retrospective case-control study was performed, including patients with unilateral hip osteoarthritis who underwent a robotic arm-assisted THA (THA-R). The controls (THA-C) were matched according to age, sex, body mass index and surgical approach. The Harris (HHS), Oxford (OHS) and Forgotten Joint (FJS) scores were collected preoperatively and 1 year postoperatively. At each review, complications were categorized into minor events, revision surgery with and without implant change. Radiographic analysis was performed on weight-bearing images of the pelvis 3 months postoperatively. The objective of the surgery was symmetrization of the THA in the contralateral healthy hip. For each measured parameter of the hip joint center of rotation (COR), global offset (GO) and articular leg length discrepancy (aLLD), the difference between the two sides corresponding to the delta symmetrization was compared. ResultsNinety-eight patients were included in the THA-R group and matched to 98 controls in the THA-C group. At 1 year postoperatively, the FJS and OHS scores were statistically higher in the THA-R group, respectively 82.1±22.3 [8.3; 100] and 40.8±8.8 [6; 48] vs. 71.2±27.8 [0; 100] and 38.1±9.7 [12; 48] in the THA-C group (p=0.004 and p=0.043). There was no difference in HHS (THA-R: 85.9±15.8 [31; 100] vs. THA-C: 85.8±13.3 [49–100] (p=0.962)). The implant revision rate at 1 year was significantly higher in the THA-C group (0% vs. 5.1% (p=0.025)). There was no difference in the reoperation without component exchange despite 3 dislocations (3.1%) in the THA-R group (5 (5.1%) vs. 9 (9.2%) (p=0.273)). The rate of abarticular pathologies (ilio-psoas irritation and greater trochanteric bursitis) was higher in the THA-C group (10 (10.8%) vs. 2 (2%) (p=0.016). Robotic acetabular assistance allowed a significantly better restitution of the horizontal position (THA-R: 1mm±4.8 [–11.7; 12.6] vs. THA-C: 4.1mm±7 [-29.6; 28] (p=0.0005)) and vertical COR (THA-R: 0.5mm±3.1 [–6; 8.3] vs. THA-C: 2mm±4.1 [–6; 14.6] (p=0.0068)). Navigated assistance of the femur did not significantly optimize the restitution of the Global Offset (THA-R: +2mm±6.4 [-16.4; 27.6] vs. THA-C: +0.5mm±7 .7 [–34; 30.2] (p=0.145)), or lower limb length (THA-R: +1.1mm±5 [–8.2; 13.5] vs. THA-C: +0.3mm±6 [-14.1; 22.5] (p=0.344). The FJS was statistically correlated with the restoration of the symmetry of the COR and the aLLD. A post-hoc power analysis confirmed sufficient potency (1-β=0.85). ConclusionRobotic acetabular assistance combined with femoral navigation improves clinical outcomes of THAs with fewer short-term complications. The precision of the positioning of the implants, optimized by the computer-assisted surgery system, is correlated with the missed joint score. Level of evidenceIII, retrospective case-control study.

Image-based robotic-assisted total hip arthroplasty through direct anterior approach allows a better orientation of the acetabular cup and a better restitution of the centre of rotation than a conventional procedure.

The aim was to investigate the contribution of robotics assisted total hip arthroplasty (THA) through direct anterior approach (DAA) in improving radiographic precision, functional results and complications. This retrospective study compared 100 primary conventional THA (cTHA) to 50 primary robotic THA (rTHA) through DAA. All cups were placed with the objective of having no anterior overhang while respecting the safe zones (SZ). Radiographic analysis included cup inclination and anteversion, vertical and horizontal changes of the rotation centre (ΔVCOR, ΔHCOR), acetabular and femoral offset. SZ were 30-50° of inclination and 10-30° of anteversion. Outliers were defined as medial displacement of the COR > 5mm, vertical displacement of the COR > 3mm superiorly. Harris hip score (HHS) and complications were compared at one year of follow-up. The robotic cups were better oriented with 98% in the global SZ versus 68% in the cTHA group (p = 0.0002). The COR was on average better restored in the robotic group in both the horizontal and vertical planes (Δ HCOR = - 5.0 ± 5.0 vs - 3.4 ± 4.9, p = 0.03; Δ VCOR = 1.6 ± 3.3 vs 0.2 ± 2.7, p = 0.04). There were fewer outliers in the rTHA group concerning VCOR (28% versus 10%, p = 0.03). There was no significant difference in HHS and complication rate at one year. The use of robotics for THA by DAA provided an advantage in controlling the orientation of the cup and the restoration of its rotation centre. Thanks to the 3D planning on CT scan, it allowed to respect the thresholds while avoiding the anterior overhangs.

A comparison of radiological and clinical outcomes between robotic-assisted and conventional total hip arthroplasty: Ameta-analysis.

The purpose of this study was to investigate whether robotic-assisted total hip arthroplasty (RATHA) is superior to conventional total hip arthroplasty (CTHA) in terms of radiological and clinical outcomes. Three databases (PubMed, Cochrane Library, and Embase) were searched for articles published before 11 May 2021. The comparison outcomes of interest included radiological and clinical outcomes. Eighteen studies involving 2845 hips that compared the radiological and clinical outcomes of RATHA and CTHA were included in this study. There was no significant difference between RATHA and CTHA in cup anteversion or complications. However, RATHA showed better outcomes in terms of leg-length discrepancy, stem alignment, cup inclination, the Lewinnek safe zone, Callanan safe zone, total complications, and intraoperative complications. Robotic-assisted total hip arthroplasty was inferior to CTHA in terms of operative time and dislocations (all p-values<0.05). The radiological and clinical outcomes of RATHA were comparable and even better than those of CTHA, except for operative time and dislocation outcomes.

Accuracy and Precision of Acetabular Component Position Does Not Differ Between the Anterior and Posterior Approaches to Total Hip Arthroplasty With Robotic Assistance: A Matched-Pair Analysis.

BackgroundDeviation from planned component placement with robot-assisted total hip arthroplasty (RA-THA) may differ based on surgical approach. The purpose of this study was to compare radiographic accuracy and precision of acetabular component position using RA-THA with the direct anterior approach (DAA) or posterior approach (PA).MethodsBetween 2016 and 2019, 134 PA RA-THA patients were matched to 134 DAA RA-THA patients based on age (±10 years), body mass index (±5 kg/m2), and sex (exact). Acetabular component position was assessed using (1) planned position on preoperative computed tomography, (2) intraoperative position, and (3) position on 6-week postoperative radiographs using the digital Ein Bild Röntgen Analyse system.ResultsAccuracy of acetabular component inclination in the PA cohort was lower than that in the DAA cohort (PA: 4.3° ± 2.8° vs DAA: 3.1° ± 2.4°, P = .001). Inclination precision was not statistically different (PA: 3° ± 2.4° vs DAA: 2.5° ± 1.8°, P = .071). Anteversion accuracy was not statistically different (PA: 4.1° ± 3.7° vs DAA: 3.5° ± 2.5°, P = .091). Acetabular component anteversion was more precise with DAA (PA: 4.1° ± 3.7° vs DAA: 2.9° ± 2.0°, P = .001). Radiographic outliers (anteversion or inclination was >10° or <−10° from the planned target) were significantly more prevalent in the PA cohort than in the DAA cohort (12 vs 3, P = .016).ConclusionsThe acetabular component can be positioned with excellent precision and accuracy when using RA-THA regardless of approach. Although the DAA resulted in a slight increase in precise placement of cup anteversion and more accurate placement of cup abduction with fewer outliers, these small differences may not be clinically meaningful.

Comparison of Preoperative Computed Tomography and Intraoperative Estimation in Predicting the Version of a Single-Wedge Femoral Stem.

Early prediction of stem version aids in optimization of combined version during total hip arthroplasty (THA). This study aimed to analyze the discrepancy between stem version and native femoral version measured by different methods, and to explore which method can better predict the stem version. We retrospectively reviewed 26 patients (39 hips) treated with robot-assisted THA in our hospital between September 2019 and December 2019. A straight, single-wedge, cementless stem (Accolade II) was used in all cases. Preoperative femoral version was measured at three levels on computerized tomography (CT) scan from the top to the middle level of femoral neck (Level 1 to Level 3). During THA, the version on cutting surface was measured prior to femoral broaching based on two reference lines: mid-cortical line and T line (trochanteric fossa to the middle of medial cortex). After femoral broaching, stem version was measured based on the femoral neck trial using Mako system (Stryker). In the statistical analysis, the difference and absolute discrepancy between stem version and femoral version measured with various methods were examined using paired t-test, and the relationship between stem version and various femoral versions were examined using correlation analysis. Mean femoral neck version (Level 1) was 9.5° ± 2.6° (range, -16.8°-42.5°), while mean stem version measured by Mako system was 19.9° ± 2.0° (range, -8.0°-49.0°). Femoral version measured with each method showed a moderate correlation with stem version (p < 0.05). There was a significant difference between stem version and femoral version except at Level 3, with a mean difference of 0.8° ± 13.6° (p=0.729). With regard to the intraoperative estimation, stem version significantly increased compared to the value based on mid-cortical line, with a mean difference of 8.4° ± 13.1° (p < 0.001). However, the mean value of stem version was a little smaller than that of femoral version measured by reference to T line, but without statistical significance (p=0.156). No postoperative dislocations occurred during the study period. No revision was required for any component. The middle level of femoral neck on CT scan and T line on cutting surface are better references to measure femoral version for predicting postoperative stem version. However, the relationship between stem version and predictive value was flexible. Therefore, further three-dimensional studies of postoperative CT are needed to validate the press-fit fixation and rotational freedom of the single-wedge stem.

Abnormal Spinopelvic Motion and Spine Deformity are Associated With Native Femoral Retroversion in the Setting of Total Hip Arthroplasty

BackgroundThe effect of spinopelvic pathology on femoral version is unclear. This study investigated variability in native femoral anteversion in patients undergoing total hip arthroplasty (THA) and its relationship to the patient’s underlying spinopelvic pattern. MethodsA retrospective chart review was performed to include in the study all patients undergoing robot-assisted THA over a 3-year period. Native femoral version was measured for each patient using a preoperative computed tomography scan and categorized as excessive, normal, or retroverted. Additionally, a subset analysis was performed for all patients with sit-to-stand dynamic pelvic radiographs available, and cases were classified by spinopelvic pattern. ResultsA total of 119 patients were included in the study with a mean age of 68.6 years; 61 (51%) were female. The median femoral anteversion for the entire study group was 6.0° (−32° to 40°, interquartile range 13.5°). Eleven patients (9.2%) had excessive femoral anteversion, 54 of the 119 (45.4%) had normal femoral version, and 54 of the 119 (45.4%) had native retroversion. Forty-two patients (35.3%) had sit-to-stand radiographs available and were subclassified by femoral version type and spinopelvic parameters. Welch’s analysis of variance demonstrated a significant difference in femoral version among spinopelvic patterns (F = 7.826, P = .003), with Games-Howell post hoc analysis showing increased retroversion in deformity-stiff patients compared to deformity-normal mobility patients (P = .003). ConclusionsThis study demonstrates that native femoral retroversion is present in a significant number of patients undergoing THA and is more common in patients with stiff spine deformities. Based on this observation, currently available spinopelvic classification systems should be modified to account for native femoral version.