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

Cup accuracy and early-term clinical outcomes of a novel, pinless, robotic-assisted total hip arthroplasty system: A first-in-human pilot study

BACKGROUND

Malpositioning of the acetabular cup represents a challenge during total hip arthroplasty (THA). The purpose of this study was to evaluate the accuracy of acetabular cup placement and early postoperative clinical outcomes with a novel, pinless, fluoroscopic-guided, robotic-assisted application for direct anterior (DA) approach THA.

METHODS

This prospective, pre-market phase 2 study enrolled 19 patients undergoing THA for osteoarthritis. Standing anteriorposterior (AP) and lateral radiographs up to 1 year postoperatively were assessed for component fixation and complications. Martell Hip Analysis software was used to assess radiographic acetabular anteversion and inclination from postoperative standing AP pelvis images and the results were compared to target and final component values from the surgical logs. Patient reported outcome measures (PROMs) were collected preoperatively, four weeks, three months, and one year after operation.

RESULTS

Mean absolute difference for anteversion and inclination from respective targets on intraoperative fluoroscopic views was 1.4° ± 1.3° (P = 0.159) and 1.3° ± 1.1° (P = 0.378). The absolute difference between postoperative radiographs and intraoperative target values was 2.91 ± 2.40° (P = 0.019) for anteversion and 3.84 ± 2.57° (P = 0.007) for inclination. The difference in target and postoperative radiographic inclination and anteversion was within 5° in 77.8% of cases, and the cup was within the Lewinnek safe zone in 16 of 18. Oxford Hip Score (OHS) (44.3 ± 4.6 vs. 22.2 ± 11.3), score on Numeric Pain Rating Scale (NRPS) (0.5 ± 1.0 vs. 5.7 ± 2.6), and Hip Osteoarthritis Outcome Score-12 (HOOS-12) Overall Score (91.4 ± 11.2 vs. 42.8 ± 20.1) were significantly improved at one year. At one-year, 88.2% and 11.8% of patients were very satisfied or satisfied.

CONCLUSION

This first-in-human study on THA utilizing a pinless, fluoroscopy-based robotic arm demonstrated high accuracy in terms of radiographic inclination and anteversion, excellent hip-specific functional outcomes and safety one year after operation. Video Abstract.

Weak hammering sounds are associated with postoperative subsidence in cementless total hip arthroplasty

PURPOSE

The aim of this study was to investigate the relationship between the hammering sound level and the presence of postoperative subsidence.

METHODS

The last five hammering sounds during the final-size broaching procedure and during the real stem insertion were recorded and analysed in 95 patients who were operated on by one of seven surgeons using two implants (Trident cup, Accolade II, Stryker; G7 cup, Taperloc Complete Microplasty Stem, Zimmer Biomet). The maximum peak was semi-automatically identified and analysed to determine the maximum C-weighted sound pressure level (LCpeak) of each of the five hammering sounds and the equivalent continuous A-weighted sound pressure (LAeq) of the entire five-sound hammering procedure.

RESULTS

Among the 95 hips, 25 (26.3%) had ≥ 3 mm of postoperative subsidence. Therefore, 125 of 475 hammering sounds (LCpeak) and 25 of 95 hammering procedures (LAeq) in both the broaching procedure and stem insertion procedure were associated with postoperative subsidence. The hammering sound level in both the broaching and stem insertion procedures were significantly weaker in patients with postoperative subsidence than in those without subsidence. Among the seven surgeons, there was intra-surgeon and inter-surgeon heterogeneity with large variance regarding the sound levels. With univariate and multivariate analyses, the hammering sound level was independently associated with postoperative subsidence in the two models.

CONCLUSION

A weak hammering sound level was associated with postoperative subsidence in THA with a cementless stem. An objective evaluation of the hammering procedure might be useful to decrease the incidence of postoperative subsidence.

Robotic-assistance is associated with better joint outcomes compared to conventional techniques in surgically routine total hip arthroplasty: a propensity-matched large database study of 3948 patients

INTRODUCTION

The outcomes of total hip arthroplasty (THA) are highly dependent upon the restoration of native hip biomechanics and optimal component positioning. Robotic technologies for THA have rapidly improved the accuracy of component positioning and maintaining the planned center of rotation. While robotic-assisted THA (RA-THA) has primarily been employed in surgically intricate cases, its potential benefits in scenarios of diminished surgical complexity remain less explored. Therefore, the purpose of this study was to assess the odds of developing systemic and joint complications following RA-THA in cases of reduced surgical complexity.

METHODS

A retrospective cohort study was conducted using the TriNetX national database to identify patients who underwent primary THA (Current Procedural Terminology code 27,130) and more specifically RA-THA identified by ICD-10-PCS code 8E0Y0CZ and Healthcare Common Procedure Coding System code S2900 from 2013 to 2022. One-to-one propensity score matching was conducted to generate 2 cohorts: (1) RA-THA and (2) conventional THA (C-THA). Systemic and joint complications were assessed at the 30-day, 90-day, 1-year, and 5-year postoperative periods.

RESULTS

Patients undergoing RA-THA had a lower risk of needing a revision THA at the 90-day, 1-year, and 5-year time points. RA-THA was associated with a lower risk of prosthetic dislocation at 90 days and 1 year and prosthetic pain at 1 year and 5 years. Dislocation of the hip or fracture of the femur was significantly lower in the RA-THA cohort at all four-time points. Patients undergoing RA-THA had a lower risk of developing deep vein thrombosis at 5 years.

CONCLUSION

These findings suggest that RA-THA has comparable systemic and less joint complication risks at 30-day to 5-year timepoints between RA-THA and C-THA. Future studies with large sample sizes and long-term follow-up are needed to understand the patient-reported outcomes and functional outcomes of RA-THA for cases with reduced surgical complexity.

Robotic-Assisted Total Hip Arthroplasty Provides Greater Implant Placement Accuracy and Lower Complication Rates, but Not Superior Clinical Results Compared to the Conventional Manual Approach: A Systematic Review and Meta-Analysis

BACKGROUND

Accurate component placement plays a critical role in the outcome of total hip arthroplasty (THA). Robotic-assisted THA (R-THA) has emerged as an option to optimize this aspect compared to the conventional manual THA (C-THA). The aim of this meta-analysis was to analyze the studies comparing R-THA and C-THA. The hypothesis was that the use of robotic technology could improve component positioning, but this advantage may not translate into clinically relevant benefits.

METHODS

The literature search was conducted on three databases (PubMed, Cochrane Library, and Web of Science) in January 2024. The screening process and analysis were conducted separately by two independent observers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The inclusion criteria were comparative studies, English language, no time limitation, and focusing on the comparison of R-THA and C-THA. Among the 1,883 articles retrieved, 38 studies (10,055 patients) were included. The meta-analysis covered radiological outcomes, clinical outcomes, perioperative parameters, complications, and revisions. The quality of each article was assessed using the "Downs and Black's checklist for measuring quality".

RESULTS

Robotic THA provided superior radiological results compared to C-THA in terms of acetabular cup placement within the Lewinnek safe zone (P < 0.01) and horizontal change of the rotation center (P = 0.03). No statistically significant difference was obtained in terms of clinical scores between the two approaches, including Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index, Forgotten Joint Score, and Merle d'Aubigné Hip Score. Robotic THA showed longer operative time (P < 0.01), but lower complication rates (P = 0.04). No difference was obtained in terms of intraoperative blood loss and revision rates.

CONCLUSIONS

The results of this meta-analysis suggest that R-THA can provide more accurate cup placement and better restoration of the native hip anatomy while reducing complication rates compared to C-THA. However, these benefits did not translate into clinical differences in terms of patient-reported outcomes between the two approaches, and R-THA required longer operative time. While the overall results suggest some benefits with the robotic technology, future studies should investigate if further technical improvements will translate into clinically relevant benefits for patients undergoing THA.

Intraoperative application of three-dimensional printed guides in total hip arthroplasty: A systematic review

BACKGROUND

Acetabular component positioning in total hip arthroplasty (THA) is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of complications. The majority of acetabular components are aligned freehand, without the use of navigation methods. Patient specific instruments (PSI) and three-dimensional (3D) printing of THA placement guides are increasingly used in primary THA to ensure optimal positioning.

AIM

To summarize the literature on 3D printing in THA and how they improve acetabular component alignment.

METHODS

PubMed was used to identify and access scientific studies reporting on different 3D printing methods used in THA. Eight studies with 236 hips in 228 patients were included. The studies could be divided into two main categories; 3D printed models and 3D printed guides.

RESULTS

3D printing in THA helped improve preoperative cup size planning and post-operative Harris hip scores between intervention and control groups (P = 0.019, P = 0.009). Otherwise, outcome measures were heterogeneous and thus difficult to compare. The overarching consensus between the studies is that the use of 3D guidance tools can assist in improving THA cup positioning and reduce the need for revision THA and the associated costs.

CONCLUSION

The implementation of 3D printing and PSI for primary THA can significantly improve the positioning accuracy of the acetabular cup component and reduce the number of complications caused by malpositioning.

Robotic-assisted total hip arthroplasty utilizing a fluoroscopy-guided system produced similar cup accuracy and precision relative to a computerized tomography-based robotic platform

Robotic assistance for total hip arthroplasty (THA) has been demonstrated to improve accuracy of acetabular cup placement relative to manual, unassisted technique. The purpose of this investigation was to compare the accuracy and precision between a fluoroscopy-based robotic total hip arthroplasty platform (FL-RTHA) and a computerized tomography-based (CT-RTHA) platform. The study included 98 consecutive FL-RTHA and 159 CT-RTHA procedures performed via direct anterior approach (DAA). All cases were performed for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Primary outcome variables included cup implantation accuracy and precision (variance). Implantation accuracy was calculated as the absolute value of the difference between pre-operative target cup angles (inclination and anteversion) and the same post-operative angles. Percentage placement in the Lewinnek safe zone was also measured for both cohorts. The FL-RTHA and CT-RTHA cohorts demonstrated a 1.2° difference in absolute values for cup inclination accuracy (4.6° ± 3.6 vs. 3.4 ± 2.7; p = 0.005), and no difference in absolute values for cup anteversion accuracy (4.7° ± 4.1 vs. 4.6 ± 3.4; p = 0.991). Cohorts demonstrated similar precision for cup inclination and anteversion placement parameters, as well as equivalent Lewinnek safe zone placement. The use of a fluoroscopy-based robotic assistance platform for primary DAA THA resulted in similar accuracy and precision of acetabular cup placement when compared to a CT-based robotic assistance system.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system produced greater improvements in patient-reported outcomes at one year compared to manual, fluoroscopic-assisted technique

INTRODUCTION

The adoption of new technology should be supported by improvements in patient-reported outcomes (PROMs). The purpose of this study was to assess the one-year PROMs of patients who underwent total hip arthroplasty (THA) using a novel, fluoroscopy-based, robotic-assisted (RA-THA) system when compared to a manual, fluoroscopic-assisted technique (mTHA).

MATERIALS AND METHODS

A review of 91 consecutive mTHA and 85 consecutive RA-THA via a direct anterior approach was conducted. All cases were performed by the same surgeon at the same institution, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included one-year Veterans RAND-12 (VR-12) Physical/Mental, Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function/Joint Replacement, and University of California Los Angeles (UCLA) Activity scores, as well as the difference between pre-operative and one-year post-operative PROMs.

RESULTS

Patients in the RA-THA cohort had lower pre-operative HOOS-JR scores compared to patients in the mTHA cohort (37.0 vs. 43.1; p = 0.031). Cohorts experienced similar one-year post-operative VR-12, HOOS, and UCLA Activity scores. Patients in the RA-THA cohort experienced greater improvements across all pre- and post-operative HOOS scores compared to patients in the mTHA cohort: Pain (+ 54.7 vs. +42.1; p = 0.009), Physical Function (-41.6 vs. -28.7; p = 0.007), and Joint Replacement (+ 46.6 vs. +33.0; p = 0.002). These differences exceeded minimum clinically important difference (MCID).

CONCLUSIONS

Both manual and robotic cohorts experienced benefit from THA at one-year post-operative. Importantly, the use of a novel, fluoroscopy-based robotic assistance system for primary THA resulted in greater improvements in PROMs at one-year relative to manual technique.

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.

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

BACKGROUND

Patient obesity is a risk factor for poor acetabular cup positioning in total hip arthroplasty (THA).

OBJECTIVE

To assess the impact of using a novel, fluoroscopy-based robotic THA system on acetabular cup placement in obese versus non-obese patients.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Fluoroscopy-based robotics in total hip arthroplasty mitigates laterality-based differences in acetabular cup placement when compared to the manual, fluoroscopic- assisted technique

BACKGROUND

Robotic assistance in total hip arthroplasty (RA-THA) has been shown to minimize laterality-based differences in acetabular cup positioning.

OBJECTIVE

To determine if the use of a novel, fluoroscopy-based RA-THA system mitigates differences in acetabular cup placement between left (L) and right (R) side hip procedures, when compared to manual, fluoroscopic-assisted technique.

METHODS

We conducted a retrospective review of 106 consecutive mTHA (40 L/66 R) and 102 RA-THA (48 L/54 R) primary direct anterior approach procedures. All cases were performed by a single right-hand-dominant surgeon, for a pre-operative diagnosis of osteoarthritis, avascular necrosis, or rheumatoid arthritis. Outcomes included acetabular cup inclination and anteversion, and the proportion of cups within the Lewinnek safe-zone.

RESULTS

The average inclination of mTHA L cases was smaller than that of mTHA R cases (41.10∘± 7.38 vs. 43.97∘± 6.27; p= 0.04). For RA-THA, L and R cup angles were similar. There were fewer overall mTHA hips within the Lewinnek safe-zone compared to RA-THA (0.59 vs. 0.78; p= 0.003), as well as fewer mTHA R cases than RA-THA R cases (0.59 vs. 0.80; p= 0.03) within safe zone.

CONCLUSION

Use of a novel, fluoroscopy-based robotic system mitigates laterality-based differences in acetabular cup placement that were observed in a manual, fluoroscopic-assisted cohort.

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

BACKGROUND

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.

METHODS

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 90 days of surgery, length of hospital stay (LOS), and visual analog scale (VAS) pain scores.

RESULTS

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. 39.5 h; 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).

CONCLUSION

Fluoroscopy-based RA-THA demonstrates low rates of postoperative complications, improved postoperative pain profiles, and shortened LOS when compared to manual, fluoroscopy-assisted THA.

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< 0.001). According to Callanan, they were 84.1% and 50%, respectively (p< 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.

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 (38.71 min ± 7.00 vs. 75.33 min ± 11.38; p < 0.001) and OR times (101.35 min ± 12.22 vs. 156.74 min ± 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.

Improved perioperative narcotic usage patterns in patients undergoing robotic-assisted compared to manual total hip arthroplasty

BACKGROUND

Robot-assisted total hip arthroplasty (RA-THA) improves accuracy in achieving the planned acetabular cup positioning compared to conventional manual THA (mTHA), but optimal dosage for peri-RA-THA and mTHA pain relief remains unclear. This study aimed to compare pain control with opioids between patients undergoing direct anterior approach THA with the use of a novel, fluoroscopic-assisted RA-THA system compared to opioid consumption associated with fluoroscopic-assisted, manual technique.

METHODS

Retrospective cohort analysis was performed on a consecutive series of patients who received mTHA and fluoroscopy-based RA-THA. The average amount of postoperative narcotics in morphine milligram equivalents (MME) given to each cohort was compared, including during the in-hospital and post-discharge periods. Analyses were performed on the overall cohort, as well as stratified by opioid-naïve and opioid-tolerant patients.

RESULTS

The RA-THA cohort had significantly lower total postoperative narcotic use compared to the mTHA cohort (103.7 vs. 127.8 MME; P < 0.05). This difference was similarly seen amongst opioid-tolerant patients (123.6 vs. 181.3 MME; P < 0.05). The RA-THA cohort had lower total in-hospital narcotics use compared to the mTHA cohort (42.3 vs. 66.4 MME; P < 0.05), consistent across opioid-naïve and opioid-tolerant patients. No differences were seen in post-discharge opioid use between groups.

CONCLUSIONS

Fluoroscopy-based RA-THA is associated with lower postoperative opioid use, including during the immediate perioperative period, when compared to manual techniques. This may have importance in rapid recovery protocols and mitigating episode burden of care.