Robotic Total Hip Arthroplasty Research Articles

Lower Intraoperative and Immediate Postoperative Complications in Robotic Versus Conventional Primary Total Hip Arthroplasty: A Retrospective Cohort Analysis of Over 360,000 Patients.

Although a trend of an improved alignment with robotic total hip arthroplasty (THA) over conventional methods has surfaced from recent series, it is unknown whether these results translate into meaningful enhancements in postoperative outcomes. To address this lack in the literature, we compared the perioperative morbidity and mortality with robotic and conventional THA in a large national cohort of 367,894 patients. We hypothesized that no significant differences would exist in the outcomes between the two groups. Records were extracted from 2016-2019 from the National Inpatient Sample (NIS) database Healthcare Cost and Utilization Project which is the largest in-patient database in the United States. From 367,894 THAs, robotics were employed for 7,863 patients. The remaining 360,031 conventional THAs served as controls. The two groups were compared for demographics, admission, and hospital stay details including costs, and mortality and morbidity data including medical and surgical complications. Descriptive statistics were used for demographic data while analytical statistics including t-tests, chi-squared tests, Fischer exact test, and Pearson chi-squared tests were used for perioperative outcomes. Statistical significance was set at p<0.005. Demographic distributions between robotic and conventional THA groups displayed similar age and sex characteristics. Shorter mean lengths of stay (1.87 days) were seen in robotic THA versus conventional THA (2.33 days) while higher costs were noted for the former (mean $68,686.71 vs $66,840.39) (p<0.005). Low overall mortality (0.03% robotic, 0.09% conventional) was seen in both groups (p>0.005). Higher comparative incidences of anemia, acute renal failure, and pneumonia were seen in conventional THA (p<0.005) while no significant differences were noted for other complications including myocardial infarction, pulmonary embolism, deep vein thrombosis, and cardiac arrest (p>0.005). Among others, lower dislocation rates, mechanical complications, periprosthetic joint infection, and periprosthetic fractures were seen with robotic THA (p<0.005). Wound complications and superficial infection rates did not differ between the two groups (p>0.005). Evidence has emerged from our results to support more routine adaptation of the robotic option of performing a THA. These can be based on lower local, systemic, and mechanical complications as demonstrated by the present study. Further evaluation of these results in follow-up would help establish the foothold of robotic surgery in total hip replacement in the modern context.

Virtual range of motion is a safe and acceptable alternative to intra-operative manual range of motion testing in direct anterior robotic total hip arthroplasty

IntroductionIn robotic total hip arthroplasty (THA), virtual range of motion (VROM) modeling allows the surgeon to account for spinopelvic motion and create an impingement-free range of motion that is patient-specific. The primary purpose of this study was to evaluate the risk of dislocation in patients undergoing direct anterior THA using VROM rather than manual ROM trialing. MethodsProspectively collected data was reviewed retrospectively of all consecutive anterior THAs performed by a single fellowship-trained surgeon. No patients were excluded from the study. VROM identified bone and implant impingement, which was recorded in degrees of hip external rotation(ER) at 0° of hip extension (standing), and in degrees of hip internal rotation(IR) at 90° of hip flexion (sitting). No patients had manual ROM trialing performed. Dislocation events were recorded during the first 3 months of follow-up. 362 patients, with a mean age of 67 and mean BMI of 28.8, were included. ResultsThis cohort, including 154 patients (42.5%) with abnormal spinopelvic motion, demonstrated zero dislocations using VROM. The average ER impingement occurred at 60.9° ER (range 20-90°), and 50.8° IR (range 25-90°). Patients with ER impingement <55° had significantly less acetabular anteversion (16.4° ±3.3°, p < 0.001). Compared to the entire cohort, anteversion of the acetabulum was also decreased in the stuck-sitting subgroup (17.4° ±3.3°, p < 0.001) and increased in the stuck standing subgroup (20.5° ±3.6°, p < 0.001). ER impingement was a stronger predictor of acetabular anteversion than spinopelvic motion category (r = 0.458). Patients with ER impingement <45° (6.4%) or IR impingement <35° (6.6%) were “early impingers”. ConclusionIn this cohort of anterior THA patients with a high proportion of abnormal spinopelvic motion, a technique utilizing only VROM produced no dislocations. An impingement-free zone of 45° ER standing and 35° IR sitting is recommended.

Accuracy of femoral component anteversion in robotic total hip arthroplasty.

Femoral component anteversion is an important factor in the success of total hip arthroplasty (THA). This retrospective study aimed to investigate the accuracy of femoral component anteversion with the Mako THA system and software using the Exeter cemented femoral component, compared to the Accolade II cementless femoral component. We reviewed the data of 30 hips from 24 patients who underwent THA using the posterior approach with Exeter femoral components, and 30 hips from 24 patients with Accolade II components. Both groups did not differ significantly in age, sex, BMI, bone quality, or disease. Two weeks postoperatively, CT images were obtained to measure acetabular and femoral component anteversion. The mean difference in femoral component anteversion between intraoperative and postoperative CT measurements (system accuracy of component anteversion) was 0.8° (SD 1.8°) in the Exeter group and 2.1° (SD 2.3°) in the Accolade II group, respectively (p = 0.020). The mean difference in anteversion between the plan and the postoperative CT measurements (clinical accuracy of femoral component anteversion) was 1.2° (SD 3.6°) in the Exeter group, and 4.2° (SD 3.9°) in the Accolade II group (p = 0.003). No significant differences were found in acetabular component inclination and anteversion; however, the clinical accuracy of combined anteversion was significantly better in the Exeter group (0.6° (SD 3.9°)) than the Accolade II group (3.6° (SD 4.1°)). The Mako THA system and software helps surgeons control the femoral component anteversion to achieve the target angle of insertion. The Exeter femoral component, inserted using Mako THA system, showed greater precision for femoral component and combined component anteversion than the Accolade II component.

Automated digital templating of component sizing is accurate in robotic total hip arthroplasty when compared to predicate software

Accurate pre-operative templating of prosthesis components is an essential factor in successful total hip arthroplasty (THA), including robotically-assisted THA (RA-THA) techniques. We sought to validate the accuracy of a novel, robotic-optimized THA planning software compared to a predicate THA planner for component sizing. We analyzed a series of 199 patients who received manual THA (mTHA) and fluoroscopy-based RA-THA at a single institution. All cases were templated using a predicate pre-operative templating software. For RA-THA cases, the novel robotic-optimized pre-operative planner software was also used for templating. The differences between templated and implanted acetabular cup, femoral head, and stem component sizes were compared based on matching within 1, 2, and ≥3 sizes. Differences in templated and implanted femoral stem implant geometry were also compared. The robot-optimized pre-operative RA-THA plans demonstrated equivalent accuracy to that of predicate pre-operative plans for both RA-THA and mTHA cases. Templated acetabular cups (90.4 vs. 86.8 vs. 82.8; p = 0.421), femoral stems (76.0 vs. 65.1 vs. 67.7; p = 0.096), and femoral heads (91.3 vs. 96.2 vs. 88.2; p = 0.302) were within +/−1 size of implanted components. No significant differences were detected in the proportion of matching templated and implanted stem geometry across the study cohorts.

CT-based, robotic-arm assisted total hip arthroplasty (Mako) through anterior approach provides improved cup placement accuracy but no difference in clinical outcomes when compared to conventional technique

BACKGROUND: With the restoration of the natural hip biomechanics, a successful total hip arthroplasty (THA) and long-term survival is pursued. Although robotic THA (rTHA) has been developed to increase accuracy of implant positioning, leg lengths and offsets, discussions about its radiological and clinical advantages over conventional THA (cTHA) continues. OBJECTIVE: The aim of this study was to compare clinical and radiological outcomes of robotic and conventional THA. METHODS: This retrospective study compares functional and radiological outcomes of 82 rTHA with a matched group of 82 cTHA in terms of age, sex, body mass index and preoperative functional scores. The minimum follow up was 12 months for all patients. Functional outcomes were Harris Hip Score (HHS) and the Western Ontario and McMaster University Osteoarthritis index (WOMAC) evaluated pre- and postoperatively. Radiological evaluations included position of cup placement according to Lewinnek and Callanan safe zones, Canal Fill Ratio (CFR), Leg Length Discrepancy (LLD), Lateral offset (LO) and Femoral Component Alignment (FCA). Complications were also evaluated. RESULTS: In the rTHA group, 91.5% (75 out of 82) of the acetabular cups were positioned within the safe zone whereas it was 63.4% (52 out of 82) for the cTHA group (p&lt; 0.001). According to Callanan, they were 84.1% and 50%, respectively (p&lt; 0.001). Between the groups, no statistically significant difference was found in CFR, LLD, HO, FCA, AI, AA, WOMAC, HHS and major complication rates. CONCLUSION: rTHA is superior to cTHA in terms of accuracy and reproducibility of the cup placement, however no apparent clinical benefit was found in short term follow.

Fluoroscopy-based robotic assistance for total hip arthroplasty improves acetabular cup placement accuracy for obese patients compared to the manual, fluoroscopic- assisted technique.

Patient obesity is a risk factor for poor acetabular cup positioning in total hip arthroplasty (THA). To assess the impact of using a novel, fluoroscopy-based robotic THA system on acetabular cup placement in obese versus non-obese patients. A review of 105 consecutive manual unassisted (mTHA) (47 Obese/58 Non-obese) and 102 robotic-assisted (RA-THA) (50 Obese/52 Non-obese) primary, direct anterior approach THA procedures was conducted. All cases were performed by a single surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Obesity was defined as a Body Mass Index (BMI) ⩾ 30 kg/m2. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone. Obese patients in the mTHA cohort had larger cup inclination angles on average compared to non-obese patients (44.82∘± 6.51 vs. 41.39∘± 6.75; p= 0.009). Obese mTHA patients were less likely to have cup placement within the Lewinnek zone compared to non-obese mTHA patients (0.48 vs. 0.67; p= 0.027). Obesity had no effect on the accuracy of RA-THA. Obesity affects the placement of the acetabular component in manual THA. The novel, fluoroscopy-based robotic THA system in this study demonstrated accurate cup placement regardless of obesity status.

Three-Dimensional CT-Based Limb Length Evaluation Is Highly Dependent on Anatomical Landmark Selection and Pelvic Asymmetry.

Pelvic skeletal asymmetry can result in rotational differences and morphologic bony prominence variance between the left and right hemipelvis. When selecting bony reference points for modern computed tomography-based robotic total hip arthroplasty planning, it is unclear which bony landmarks are the most reliable and accurate, especially in the presence of significant pelvic asymmetry. A retrospective study was conducted utilizing a database of computed tomography scans. Multiple bony landmarks in the pelvis and femur were selected for comparison, with the aim of measuring pelvic asymmetry. Specifically, the study measured the average difference in lateral offset between the left and right hemipelvis caused by pelvic asymmetry. Landmarks were also compared to determine the impact of pelvic asymmetry on hip length, femur length, and limb length discrepancies. Furthermore, a scenario was simulated in the software whereby a total hip replacement was inserted, potentially changing the hip length. The impact of pelvic reference point selection on the measurement of this simulated change in hip length was examined. This study population showed widespread pelvic asymmetry. The anatomical landmarks of the opposite side cannot be relied upon for predicting the anatomy of the affected side. The center of rotation axis is more reliable than the inferior obturator foramen axis for hip length discrepancy due to pelvic asymmetry (P < .05). Current computer-assisted surgery THR software reports measurements of global offset and hip length that do not consider pelvic asymmetry. Surgeons are not given confidence ranges to represent the potential impact of asymmetry on the global offset and hip length values. Surgeons following these numbers to guide implant position may incur implant placement error should significant pelvic asymmetry be present in a given patient.

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.

Is the Acetabular Cup Orientation Different in Robot-Assisted and Conventional Total Hip Arthroplasty With Right-Handed Surgeons Using an Anterolateral Approach?

Introduction Total hip arthroplasty (THA) is one of the most successful orthopaedic procedures. Survival rates from 90% at 10 years to 93% at 20 years have been reported in different studies. Differences in implant and patient characteristics can undoubtedly explain some of this variability observed in prosthesis durability, but the effect of surgical technique and implant orientation cannot be ignored. Therefore, many intraoperative methods (anatomic landmarks, intraoperative x-ray, fluoroscopy, navigation, and robotic surgery) have been attempted to avoid acetabular component malpositioning.Although postoperative computed tomography (CT) is accepted as the gold standard for the measurement of acetabular anteversion, it remains controversial in respect of costs and radiation exposure. The aim of this study was to examine how acetabular component orientation was affected in robotic and conventional THA operations performed by two surgeons with right-hand dominance. Material and methods The study included 113 primary THA operations performed on 113 patients between 2017 and 2022 in two groups: (i) robotic THA (Mako, Stryker Corporation, Kalamazoo, Michigan, United States) (55 patients) and (ii) conventional THA (58 patients). The patients comprised 51 males and 62 females. THA was performed on 54 right-side hips and 59 left-side hips. The operations were performed by two orthopaedic surgeons, each with 20 years of arthroplasty experience, on all the patients in the lateral decubitus position with an anterolateral approach. In all the cases, the orientation of the acetabular component was 40° inclination and 20° anteversion. Difficult THA procedures (patients with developmental dysplasia of the hip (DDH), a history of hip surgery, revision THA, defect or deformity of the acetabulum, a history of scoliosis or lumbar posterior surgery, or those requiring proximal femoral osteotomy) were excluded from the study. Using the Liaw and Lewinnek methods, the acetabular component anteversion was measured on the radiographs taken in the optimal position postoperatively and the acetabular cup inclination angles were measured on the pelvis radiographs. The groups were compared using the Kolmogorov-Smirnov, Pearson Chi-square and Mann-Whitney U statistical tests. The limits were accepted as 40±5° for inclination and 20±5° for anteversion. Results No statistically significant difference was determined between the groups in respect of age, gender, or operated side. No statistically significant difference was determined between the optimal acetabular cup inclination angles of the robotic and conventional THA groups (p = 0.79). No statistically significant difference was determined between the optimal acetabular cup anteversion angles of the left and right conventional THA groups. Statistically significantly better results were determined in the robotic group in respect of acetabular cup anteversion (p<0,001). Conclusion The optimal orientation of the acetabular component is a key factor for successful THA. Otherwise, revision surgery is inevitable for reasons such as instability, impingement, or increased wear. The results of this study demonstrated that robotic surgery was superior to the conventional method in the placement of the acetabular component in the desired orientation.

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.

Equivalent radiation exposure with robotic total hip replacement using a novel, fluoroscopic-guided (CT-free) system: case-control study versus manual technique.

Accurate and precise positioning of the acetabular cup remains a prevalent challenge in total hip arthroplasty (THA). Robotic assistance for THA has increased over the past decade due to the potential to improve the accuracy of implant placement. However, a common criticism of existing robotic systems is the requirement for preoperative computerized tomography (CT) scans. This additional imaging increases patient radiation exposure, as well as cost, and requires pin placement during surgery. The goal of this study was to analyze the radiation burden associated with a novel, CT-free robotic THA system compared to an unassisted manual THA approach (n = 100/arm). On average, the study cohort had a higher number of fluoroscopic images captured (7.5 vs. 4.3 images; p < 0.001), radiation dose (3.0 vs. 1.0mGy; p < 0.001), and a longer duration of radiation exposure (18.8 vs. 6.3s; p < 0.001), per procedure, than the control group. Additionally, no learning curve was detected by CUSUM analysis with respect to the number of fluoroscopic images taken during the adoption of the robotic THA system. While statistically significant, in comparison to published literature, the radiation exposure of the CT-free robotic THA system was comparable to that of unassisted manual THA approach and less than that of CT-based robotic approaches. Thus, the novel CT-free robotic system likely poses no clinically significant increase in radiation exposure to the patient compared to manual approaches.

Robotics in Total Hip Arthroplasty: Current Concepts.

This current concepts article reviews the literature pertaining to the use of robot-assisted systems in total hip arthroplasty (THA). The bulk of the literature is regarding the MAKO (currently the most used system worldwide) and the historic ROBODOC robotic systems. There is a paucity of literature available on other systems, with several still in pilot-phase development. Whilst the evidence shows improved radiological outcomes with robotic THA, functional outcomes are equivocal between conventional and robotic techniques. Acceptance of robotic THA worldwide is limited by its accessibility including cost, and by already exceptional results with the conventional technique. It is, however, a rapidly developing area of orthopaedic surgery. This article discusses the history of robotics in THA, current surgical techniques, functional and radiological outcomes, and ongoing avenues for development.

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.

Dislocation risk after robotic arm-assisted total hip arthroplasty: a comparison of anterior, lateral and posterolateral approaches.

Dislocation is a major cause of early failure after THA and is highly influenced by surgical approach and component positioning. Robotic-arm assisted arthroplasty has been developed in an attempt to improve component positioning and reduce postoperative complications.The purpose of this study was to compare the rate of dislocation after robotic total hip arthroplasty through 3 different surgical approaches. All patients who had undergone robotic arm-assisted THA at 3 centres between 2014 and 2019 were reviewed. After applying exclusion criteria, 1059 patients were included in the study. An anterior approach was used in 323 patients, a lateral approach in 394 and a posterior approach in 342 patients.Episodes of dislocation were recorded after 6 months follow-up. Stem anteversion, cup anteversion, cup inclination and combined anteversion were collected using the integrated navigation system.Cumulative incidence (CI), incidence rate (IR) and risk ratio (RR) were calculated with a confidence interval of 95%. 3 cases of dislocation (2 posterior approach, 1 anterior approach) were recorded, with a dislocation rate of 0.28% and an IR of 0.14%.The rate of placement of the cup in the Lewinnek safe zone was 82.2% for the posterior approach, 82.0% for the lateral approach and 95.4% for the anterior approach.The rate of placement in the combined version safe zone was 98.0% for the posterior approach, 73.0% for the lateral approach and 47.1% for the anterior approach.The incidence rate of dislocation was 0.30% for the anterior approach, 0.34% for the posterior approach and 0% for the lateral approach. The robotic arm-assisted technique is associated with a low risk of dislocation. The combined version technique appears to be a reliable way to reduce the risk of dislocation through the posterolateral approach but does not appear to be essential when using the lateral and anterior approaches.

Robotic total hip arthroplasty: past, present and future

Hip osteoarthritis is one of the leading causes of global disability and according to the latest National Joint Registry report, more than 280,000 primary hip procedures were performed in England and Wales over the past 3 years. The evolution of surgical technology has resulted in the introduction of robotic arm-assisted total hip arthroplasty (THA) that presents the opportunity to achieve more accurate and reproducible implant positioning, in addition to executing a patient-specific plan. Robotic THA has been shown to be superior in restoring the centre of rotation, combined anteversion, offset and leg length, which are critical surgeon-controlled variables that influence postoperative outcomes. Furthermore, robotic THA has been associated with a reduced length of stay and a trend towards a reduced risk of peri-operative complications. Limitations of robotic THA include the substantive installation costs, learning curve, additional radiation exposure and the limited compatible implants. The potential of this technology is immense and as more data emerge, we will be able to ascertain the impact of robotics on revision rates and long-term functional and patient-reported outcomes.

Does robotic-assisted computer navigation improve acetabular cup positioning in total hip arthroplasty for Crowe III/IV hip dysplasia? A propensity score case-match analysis.

Total hip arthroplasty (THA) in patients with hip-dislocation dysplasia remains challenging. This study aims to evaluate whether these patients may benefit from robotic-assisted techniques. We reviewed 135 THAs (108 conventional THAs and 27 robotic-assisted THAs) for Crowe type III or IV from January 2017 to August 2019 in our institution. Robotic-assisted THAs were matched with conventional THAs at a 1:1 ratio (27 hips each group) using propensity score matching. The accuracy of cup positioning and clinical outcomes were compared between groups. The inclination of the cup for conventional THAs and robotic THAs was 42.1 ± 5.7 and 41.3 ± 4.6 (p = 0.574), respectively. The anteversion of the cup for conventional THAs was significantly greater than that of robotic THAs (29.5 ± 8.1 and 18.0 ± 4.6; p < 0.001), respectively. The ratio of the acetabular cup in the Lewinnek safe zone was 37% (10/27) in conventional THAs and 96.3% (26/27) in robotic THAs (p < 0.001). Robotic THAs did not achieve better leg length discrepancy than that of conventional THAs (- 0.4 ± 10.9mm vs. 0.4 ± 8.8mm, p = 0.774). There was no difference in Harris Hip Score and WOMAC Osteoarthritis index between groups at the 2-year follow-up. No dislocation occurred in all cases at the final follow-up. Robotic-assisted THA for patients with high dislocation improves the accuracy of the implantation of the acetabular component with respect to safe zone.

Robotic total hip arthroplasty for fused hips in ankylosing spondylitis patients: Our experience with robotic arm technology.

The conversion from a fused hip to conventional total hip arthroplasty (THA) in patients with ankylosing spondylitis can be challenging. The problems are related to patient positioning, surgical exposure, femoral neck osteotomy, identifying the true acetabulum, and proper implant positioning. This case series describes our experience using the Mako Robotic-Arm in four bilateral THA procedures (each conducted in a single session) and one unilateral procedure in a fifth patient. Robotic total hip arthroplasty (RTHA) simplified THA by providing real-time information on the relative positions of the femur, pelvis, instruments, and implants to guide the surgery and implant placement.

ICD-10 Coding Mismatch in Computer and Robotic Assisted Primary Total Hip Arthroplasty.

The International Statistical Classification of Disease, 10th Revision Procedural Coding System (ICD-10-PCS) is a granular procedural classification system with the ability to precisely classify types of technology utilized in total hip arthroplasty (THA). However, coding nuances and the rapidly evolving nature of technology may lead to coding inaccuracies. The purpose of this study is to determine the accuracy of ICD-10-PCS coding in computer-navigated and robotic THA and discuss its implications on clinical data. The arthroplasty database at a single institution was retrospectively reviewed for all primary computer and robotic assisted THAs performed between October 2015 to November 2020. The type of technology utilized was determined from the surgical record and compared with the ICD-10-PCS codes applied to each procedure. A total of 3721 technology-assisted THAs were identified and reviewed. 87.5% of technology-assisted THAs were coded with the correct type of technology. The most common error in computer navigated THA was the omission of the technology code, while the most common error in robotic assisted THA was the designation of codes for both computer navigation and robotic assistance. The granular nature of ICD-10-PCS allows for precise distinction between types of technology-assisted THA. However, rates of coding inaccuracy bring concern for the integrity of this data. The inaccuracy of ICD-10-PCS data is not insignificant and should bring concern for the validity of collective data sets that use it exclusively for its procedural granularity.

Improved accuracy and fewer outliers with a novel CT-free robotic THA system in matched-pair analysis with manual THA

Accurate component orientation and restoration of hip biomechanics remains a continuing challenge in total hip arthroplasty (THA). The goal of this study was to analyze the accuracy/reproducibility of a novel CT-free and pin-less robotic-assisted THA (RA-THA) platform compared to manual THA (mTHA). This matched-pair cadaveric study compared this RA-THA system to mTHA (n = 33/arm), both using the assistance of fluoroscopic imaging, in a group of 14 high-volume arthroplasty surgeons. In both groups, surgeons were asked to aim for 40°/15° for cup inclination/version, and 0 mm of leg length discrepancy (LLD). A validated and accurate method using radio-opaque markers measured cup inclination/version and LLD. The accuracy and reproducibility (fewer outliers) of cup inclination was significantly improved in the robotic group (1.8° ± 1.3° vs 6.4° ± 4.9°, respectively, robotic vs manual; p < 0.001), with no significant difference between groups for version. The reproducibility of LLD was significantly improved in the robotic group (p = 0.003). For all parameters studied, the robotic group had an improved accuracy and lower variance (fewer outliers). The percentage of cases within the more restrictive Callanan safe zone was 100% for RA-THA vs 73% for mTHA (p = 0.002). The CT-free RA-THA platform, using only fluoroscopic imaging, demonstrated more accurate acetabular cup positioning, when compared to the mTHA procedures performed by high-volume hip surgeons (naive to this RA-THA platform), with respect to cup inclination and placement within the Lewinnek/Callanan safe zones. Future study must incorporate economic factors, lower volume surgeons, clinical and patient-centric outcomes, and other radiographic parameters in controlled studies in large sample sizes.

Personalized Cup Positioning Guides Improved Cup Positioning and Hip Ranges of Motion in Robotic Assisted Total Hip Arthroplasty.

ObjectivePrecise hip cup positioning is essential for the prevention of component impingement and dislocation in robotic assisted total hip arthroplasty (THA). Currently, the robotic system uses a mechanical alignment guide (MAG) for cup placement, which is one-size-fits-all, and the optimal cup positioning is controversial. Robotic assisted THA has not used any personalized cup positioning guides. The goal of this study was to identify an optimal guide for cup placement in robotic assisted THA to improve prognosis and life quality after THA.Materials and MethodsPelvis and femoral CT data of 47 participants were retrospectively collected for preoperative planning of robotic THA. The universal MAG guide and three personalized guides, including acetabular rim labrum guide (ARLG), transverse acetabular ligament guide (TALG), and ischiatic-pubis line guide (IPLG), were used to pose cups in the acetabulum of each participant. The position of cups was evaluated by inclination and anteversion; the function of hip joints was evaluated by hip ranges of motion, including abduction, adduction, extension, flexion, internal rotation, and external rotation.ResultsIn terms of cup positioning, ARLG provided a bigger cup inclination (p < 0.0001), while IPLG and TALG provided smaller cup inclination (p < 0.001) than MAG; the three personalized guides provided larger cup anteversion (p < 0.0001) than MAG. In terms of HROMs, compared with the use of MAG, the use of three personalized guides significantly decreased abduction (p < 0.0001), extension (p < 0.0001), and external rotation (p < 0.0001), but increased significantly flexion (p < 0.0001) and internal rotation (p < 0.0001); the use of ARLG significantly reduced adduction (p < 0.0001), but the use of IPLG and TALG increased adduction (p < 0.0001).ConclusionCompared with MAG, personalized guides provided greater flexion and internal rotation, which may reduce the risk of posterior dislocation. Among the three personalized guides, IPLG is the most reliable one for the preoperative planning of robotic assisted THA.