Comparison of Postoperative Instability and Acetabular Cup Positioning in Robotic-Assisted Versus Traditional Total Hip Arthroplasty

Incidence and characteristics of noise generation in total hip arthroplasty with ceramic-on-ceramic bearings : a comparison between robotic-assisted surgery and conventional methods

Aims

To evaluate the impact and risk factors of robotic-assisted surgery (RAS) on noise generation in total hip arthroplasty (THA) with ceramic-on-ceramic (CoC) bearings in comparison to conventional (CON) manual methods.

Methods

A secondary analysis of a prospective multicentre randomized controlled trial - conducted from June 2021 to July 2022 - included 74 patients with CoC bearings, equally divided between RAS and CON groups. Noise incidence, characteristics, and duration were documented. Radiological assessments and logistic regression analysis were performed to identify predictors of noise or squeaking.

Results

The incidence of overall noise complaints was higher in the CON group compared to the RAS group, with a statistically significant difference observed at the early postoperative stage. Specifically, at 14 days post-surgery, 5.4% of patients in the RAS group and 32.4% in the CON group reported noises (p = 0.008), while at 24 weeks, the rates were 5.4% and 21.6%, respectively, with no statistically significant difference (p = 0.089). RAS showed superior alignment and precision in component placement. Logistic regression analysis identified conventional surgery as a significant predictor of noise complaints (odds ratio 7.10 (95% CI 1.51 to 33.33); p = 0.013). Additionally, the probability distributions of different acetabular alignment and abduction angles were plotted and analyzed. No differences in functional status or patient-reported outcomes were found between groups.

Conclusion

RAS in THA with CoC bearings reduces the incidence and severity of noise-related complications, and is likely due to more precise and appropriate component placement, which may improve outcomes.

The Impact of Previous Lumbar Spine Surgery on Primary Total Hip Arthroplasty: Minimum 2-Year Outcomes Controlling for Approach and Technology

BACKGROUND

Prior lumbar spine surgery (LSS) can limit spine mobility, potentially increasing hip motion requirements. This study aimed to assess the influence of LSS on primary total hip arthroplasty (THA).

METHODS

Retrospective analysis was conducted on patients who underwent THA with prior LSS. Included patients had completed patient-reported outcomes (PROs) and visual analog scale for pain questionnaires or had a documented revision surgery with a minimum 2-year follow-up. Patients were propensity matched to a benchmark control group of patients who did not have previous spine pathology in a 1:3 ratio, controlling for age at surgery, surgical approach, use of advanced technology, sex, and body mass index. The analysis included comparisons of hip arthroplasty thresholds and complications. Subanalyses based on the type of lumbar surgery and type of approach were also conducted.

RESULTS

There were 244 hips included in the study. The LSS group reported comparatively lower postoperative PRO scores. However, the LSS group experienced a similar magnitude of improvement. The LSS group met patient acceptable symptom state threshold for Forgotten Joint Score at a significantly lower rate. The LSS had a higher frequency of complications leading to revision THA with a relative risk of 24 and a relative risk of 20.8 for revision THA due to instability. Comparing patients by type of LSS, PROs, the percentage of patients reaching hip arthroplasty thresholds, and the revision THA rates were similar. There was no difference in complications considering the type of approach.

CONCLUSIONS

Patients who had prior LSS who underwent primary THA demonstrated equivalent improvements in PROs, but achieved lower overall postoperative scores and met hip arthroplasty thresholds at lower rates. Furthermore, patients undergoing primary THA with prior LSS had a higher risk of complications leading to revision surgery, including a 24-fold relative risk for complications leading to revision and a 20.8-fold relative risk of revision due to instability.

Accuracy of Implant Positioning in Total Hip Arthroplasty via a Supine Direct Anterior Approach Using Fluoroscopy

Background: Adequate implantation is important to avoid complications following total hip arthroplasty (THA). This study aimed to evaluate the accuracy and precision of implant placement in the direct anterior approach (DAA) using fluoroscopy in comparison with the anterolateral approach in lateral decubitus position (OCM) using a single implant. Methods: We retrospectively compared propensity score-matched THAs in DAA with fluoroscopy and in OCM. The achievement ratio of the Lewinnek cup safe zone, absolute difference in alignment, and positioning from preoperative planning was evaluated and compared between each approach. Results: 33 patients in both groups were eligible for this study. Significantly more cups were inside the safe zone in the DAA group than in the OCM group (33/33 vs. 25/33, p=0.0048). No significant differences were found between the DAA group and OCM group regarding the discrepancy from the target cup inclination, anteversion, and three-dimensional positioning. No significant difference was noted in stem alignment; however, the equality of coronal alignment variances was smaller in the DAA group (p=0.0047). No significant differences were found in the clinical score and complication rate. Conclusion: The DAA using fluoroscopy may provide more accuracy for cup placement and precision for stem placement than OCM.

Robotic-Assisted Surgery Does Not Decrease Prosthetic Impingement in Total Hip Arthroplasty: A Retrieval Analysis

BACKGROUND

Prosthetic impingement after total hip arthroplasty (THA) has been associated with instability and may be a cause of accelerated polyethylene wear and pain. Previous retrieval studies report a high prevalence of impingement in acetabular liners. Robotic technology has the potential to reduce THA instability as it enables technical precision and optimizes implant positioning. However, whether robotics can improve impingement prevalence is unknown. Thus, the objectives of this study were to: (1) determine the prevalence and severity of acetabular liner impingement with robotic navigation; and (2) compare impingement prevalence with a control cohort of manually placed THA liners.

METHODS

There were 18 robotic-assisted liners and 11 non-robotic controls scored for the presence and severity of impingement. Radiographic measurements of acetabular inclination and anteversion were assessed using prerevision standing radiographs. Femoral head size (36 being the most common), length of implantation, revision indication, age, gender, and body mass index were recorded.

RESULTS

Of the robotic liners, 61% showed impingement, while 45% of the non-robotic liners showed impingement (P = 0.14). The robotic group demonstrated a lower variance of inclination (robotic: 41.7° ± 3.9, control: 42.8° ± 7.1, P = 0.64) and lower anteversion variance (robotic: 22.8° ± 2.8, control: 20.8° ± 7.9, P = 0.43), but mean values did not differ between the groups. Impingement presence and severity were not related to head size, length of implantation, or other demographic variables.

CONCLUSIONS

This study suggests that the use of robotic-assisted technology employing modern-day implants with larger diameter heads does not reduce the prevalence or severity of prosthetic impingement in retrieved acetabular liners from revision THA.

Changes of spino-pelvic characteristics post-THA are independent of surgical approach: a prospective study

AIMS

Spinopelvic characteristics change after THA. Whether this change varies between approaches, is of interest for pre-op cup orientation planning. The aims of this study were to (1) Characterize changes in standing PT amongst patients with hip osteoarthritis treated with THA; (2) Test whether certain patient-related factors may predict PT change; and (3) Assess the association between surgical approach and PT change.

METHODS

This was a prospective, two-center, radiographic outcome study including 424 hips, consisting of anterior approach for 171 (40.3%) hips, lateral approach for 181 hips (42.7%) and posterior approach for 72 hips (17.0%). Spinopelvic characteristics were determined from lateral radiographs (before and one year after THA). Parameters of interest included: Pelvic tilt (PT), lumbar lordosis, sacral slope, pelvic incidence. PT change of more than 7 ° was considered clinically relevant.

RESULTS

Pelvic tilt increased by 2 ° from 15.1 ° (± 8.9) to 17.1 ° (± 9.7) after THA (p < 0.001). 19 hips (4.5%) experienced a relevant PT decrease, 337 (79.5%) had no clinically significant change in pelvic tilt, and 68 (16.0%) showed a moderate increase. Age, female sex and preoperative spinopelvic parameters including PT, SS and PI were predictive of PT change more than 7 °. PT increased most with lateral approach (2.9 ± 6.2) and least with anterior approach (1.1 ± 6.2, p = 0.024).

CONCLUSION

Preoperative PT is the best predictor for PT change. PT is generally normalizing after THA and patients with low PT due to hip flexion contractures tend to increase PT after THA, few patients with high PT will decrease after THA. Anterior approach with capsulectomy was associated with the least change in PT post-THA. However, the approach-specific changes, although statistically significant, were too small to be considered during clinical practice, therefore no approach-specific prediction of PT change needs to be considered during preoperative planning for primary THA.

Recovery Time and Success: A Comparative Study of Robotic and Manual Total Hip Arthroplasty Outcomes

BACKGROUND

Despite the growing utilization of robotic-assisted total hip arthroplasty (rTHA), major debate remains regarding its comparative effectiveness in achieving optimal patient outcomes compared to manual total hip arthroplasty (mTHA). This study aimed to compare both the rate and time to achieve minimal clinically important difference (MCID) between rTHA and mTHA.

METHODS

We conducted a retrospective analysis comparing 341 rTHAs with a 1:3 propensity score-matched cohort of 1,023 mTHAs performed from 2016 to 2022. Propensity scores were generated based on age, sex, body mass index, and Charlson comorbidity index. Patient-reported outcomes were evaluated using preoperative and postoperative scores of Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical, PROMIS Physical Function-10a (PF-10a), and Hip disability and Osteoarthritis Outcome Score - Physical Function Shortform (HOOS-PS). The time to achieve MCID was assessed using survival curves with and without interval censoring, and statistical comparisons were performed using log-rank and weighted log-rank tests.

RESULTS

Manual total hip arthroplasty demonstrated a significantly higher rate of achieving MCID for PROMIS Global Physical (84.1 versus 79.8%, P = 0.003) and HOOS-PS (60.0 versus 44.9%, P < 0.001), while rates for PROMIS PF-10a were similar (58.6 versus 56.0%, P = 0.085). In the interval-censored analysis, rTHA achieved MCID for HOOS-PS significantly faster than mTHA (0.67 versus 1.0 months, P < 0.001). However, no significant differences were found for PROMIS Global Physical (0.24 versus 0.70 months, P = 0.18) and PROMIS PF-10a (1.60 versus 3.03 months, P = 0.73) when compared to mTHA.

CONCLUSIONS

We conducted a propensity score-matched analysis of rTHA and mTHA, accounting for baseline characteristics, but not factors such as case difficulty and anatomic complexity. We found that rTHA achieved MCID faster, while mTHA had a higher overall proportion of MCID achievement. Robotic-assisted surgery may expedite initial recovery, while manual techniques may lead to better long-term outcomes.

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 Through the Posterior Approach

Background

Robotic-assisted total hip arthroplasty (THA) through the posterior approach is indicated in cases of symptomatic hip arthritis. The goal of the procedure is to relieve pain and restore function while minimizing postoperative complications such as dislocation. Dislocation often occurs despite traditionally well placed components1,2. The hip-spine relationship can be a causative factor in postoperative instability, particularly in patients with altered spinopelvic kinematics as a result of spinal fusions or degenerative spine disease, in whom component placement based on anatomic landmarks may lead to functional malpositioning3,4. Therefore, we present our technique for robotic-assisted THA through the posterior approach, which incorporates patient-specific spinopelvic kinematic data to maximize impingement-free range of motion and minimize the risk of dislocation.

Description

Preoperative computed tomography (CT) scans are obtained in order to generate a 3D model of the patient's unique hip anatomy. Lateral lumbar radiographs with the patient in the sitting and standing positions are also obtained preoperatively. The sacral slope is measured in each position, imported into the robotic software, and utilized to aid in positioning the components for optimal leg length, offset, and stability of the hip replacement based on the patient's unique spino-kinematic profile. The procedure begins with 3 partially threaded pins being driven into the ipsilateral iliac crest about 2 cm posterior to the anterior superior iliac spine. The robotic pelvic array is fastened to the pins. A standard posterior approach to the hip is utilized. Skin and subcutaneous tissues are dissected down to the iliotibial band and gluteus maximus fascia. The fascia is longitudinally incised, and a small metallic pin is malleted into the distal aspect of the greater trochanter. Initial leg length and offset values are captured. The short external rotators and posterior hip capsule are elevated. The hip is dislocated, and a neck resection is made at a level determined preoperatively with use of the robotic software. The acetabulum is exposed, and osseous registration is carried out to establish a relationship between the 3D model built with use of the robotic software and the patient's anatomy in vivo. The acetabulum is single-reamed, and the final cup is impacted in the desired position. The proximal femur is broached with increasingly sized broaches until rotational and axial stability has been achieved. A trial femoral neck and head are attached to the final broach, and the hip is reduced. Posterior and anterior hip stability are assessed, and leg length and offset are rechecked via the robotic system. Once the surgeon is satisfied, the hip is dislocated, the broach is removed, and the final femoral stem and head are manually implanted. The hip is then reduced for the final time. Closure is performed according to surgeon preference.

Alternatives

Surgical alternatives include THA with use of manual instrumentation or navigation through other approaches to the hip, including the direct anterior, anterolateral, and direct lateral approaches5-7. Nonoperative alternatives include physical therapy, the use of nonsteroidal anti-inflammatory pain medication, and intra-articular corticosteroid injections8.

Rationale

Robotic-assisted THA is particularly advantageous in patients with abnormal spinopelvic kinematics who require precise and specific component positioning to optimize hip stability9-11. In these patients, manually placing components relative to anatomic landmarks may lead to functional malpositioning and ultimately dislocation. Additionally, cases in which there is an anticipated difficulty in acetabular exposure or preparation because of a large body habitus or large pannus, retained acetabular hardware, or severe acetabular wear or dysplasia may benefit from the use of this technique9.

Expected Outcomes

Patients who undergo robotic-assisted THA through the posterior approach should expect excellent clinical outcomes in addition to low rates of complication and revision12. Robotic-assisted THA has been shown to lower the risk of dislocation compared with manual techniques10,11. In a study by Bendich et al., a robotic-assisted THA cohort had a 0.3 odds ratio of reoperation for dislocation compared with a manual THA cohort10.

Important Tips

Stable array pins are critical in order to obtain accurate leg length and offset measurements intraoperatively.When registering the acetabulum via the robotic software, aim for maximum spread of captured points to ensure accuracy of cup placement.In large-statured patients or patients with a particularly stiff hip, in whom anterior femoral retraction is difficult, disconnect the reamer from the robotic arm and place it into the acetabulum by hand before reconnecting it to the robotic arm. Remove the anterior acetabular retractor and set the reaming orientation to 50° of inclination and 10° of anteversion. Final cup position is kept in the desired orientation.Remember that the robotic-assistance device is just a surgical tool, and the quality of its output relies on the quality of its input. If there is concern for an error in component placement, intraoperative radiographs should be obtained.

Acronyms and Abbreviations

THA = total hip arthroplastyCT = computed tomographyDVT = deep vein thrombosisIT = iliotibial.

Greater anterior pelvic tilt and lumbar mobility in females compared to males undergoing periacetabular osteotomy: A matched cohort study

Purpose

The functional hip-spine interaction is increasingly noted in hip preservation by periacetabular osteotomy (PAO), while potentially affecting the impingement-free acetabular reorientation. However, the clinically relevant sex-related differences in lumbopelvic alignment have been poorly studied. Thus, the purpose of this study was to evaluate a matched PAO patient cohort for sex-related differences in lumbopelvic alignment.

Methods

Out of 138 patients undergoing PAO between January 2024 and September 2024 at one high-volume centre, there were 68 data sets (34 male, 34 female) included. The data sets of this diagnostic cohort study were prospectively collected, and the patients were matched in a 1:1 ratio for sex, age and acetabular morphology (hip dysplasia, borderline hip dysplasia, acetabular retroversion). Lumbopelvic alignment was assessed with serial sagittal lumbopelvic radiographs in standing, relaxed-seated and deep-seated positions. Each radiograph was reviewed for pelvic tilt (PT), lumbar lordosis and sacral slope.

Results

Females showed a significantly lower PT in standing (7.8 vs. 14.3°, p < 0.001), relaxed-seated (28.1 vs. 34.9°, p = 0.012) and deep-seated (3.7 vs. 11.0°, p = 0.013) positions. Furthermore, females had a significantly increased lumbar mobility (Δ relaxed-seated - deep-seated position - 35.4° vs. 27.0°, p = 0.003), while there was no sex-related difference in sacral mobility (p > 0.05).

Conclusion

There are sex-related differences in functional lumbopelvic alignment across various positions of daily living in patients undergoing PAO. With a greater anterior PT, females are at risk of an anterior hip impingement. Thus, the intraoperative anterior and posterior wall reorientation by PAO should be adapted to the sex-related lumbopelvic alignment to ensure an impingement-free surgical outcome.

Level of Evidence

Level IV, case series.

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.

Perceptions and attitudes regarding robotic total hip arthroplasty: a patient stakeholder survey

To describe the attitudes and preferences of patients pertaining to robotic-assisted total hip arthroplasty (RA-THA) with the long-term objective of designing a prospective randomized-controlled trial (RCT) to evaluate the efficacy of RA-THA compared to conventional technique. A cross-sectional survey of patients attending an outpatient high-volume academic arthroplasty clinic chosen was administered from December 2023 to May 2024. The survey comprised 31 items including patient demographic, patient reported factors of significance and perceptions surrounding RA-THA. Ninety-seven patients completed the survey with a mean age of 67.5 ± 9.1 years and with 63% of patients being female. The majority of respondents were not at all familiar with RA-THA (69%). Common perceptions of RA-THA compared to conventional technique included a smaller incision (41%), lower chance of developing infection (47%), shorter length of surgery (41%), less blood loss (41%), lower cost (22%), shorter length of stay (30%), more precise implant positioning (46.8%), lower post-operative pain (29%), and lower post-operative complications (36%). Very important outcomes to be assessed in future investigations included post-operative range of motion (91%), implant longevity (91%), dislocation risk (90%), post-operative pain (89%), and infection risk (87%). Patient familiarity with robotic-assisted total hip arthroplasty is low. Patient perceptions regarding RA-THA compared to conventional technique are favorable, despite limited evidence to date. Important factors to be assessed in future RCTs include range of motion, implant longevity, dislocation risk, and infection risk. Findings of this study can inform a clinically relevant RCT assessing RA-THA compared to conventional technique.

Robotic-Assistance in Total Hip Arthroplasty Is Associated With Decreased Dislocation Rates

Background

As the use of robotics in total hip arthroplasty (THA) continues to gain popularity, differences in clinical outcomes when compared to manual techniques have remained unclear. This study aimed to compare postoperative complications between patients undergoing robotic-assisted techniques and manual THA for primary osteoarthritis at 90 days, 1 year, and 2 years.

Methods

Using an all-payer national database, we identified 405,048 patients who underwent either robotic-assisted or manual THA for primary osteoarthritis. A propensity match was performed for age, sex, a comorbidity index, chronic kidney disease, obesity, and diabetes, resulting in 7652 patients in each cohort. We assessed postoperative outcomes, including surgical site infections, pulmonary emboli, venous thromboemboli, wound complications, dislocations, aseptic revisions, periprosthetic joint infections, and periprosthetic fractures. We completed bivariate analyses via chi-square tests to assess categorical variables. We utilized student's t-tests to compare continuous variables, including ages and comorbidities. Odds ratios (ORs) were calculated for complications using 95% confidence intervals (CIs).

Results

The robotic-assisted cohort had lower rates of dislocation at 90 days (0.93 vs 1.41%, OR 0.65, 95% CI 0.48-0.88, P = .007), 1 year (1.32 vs 1.92%, OR 0.68, 95% CI 0.53-0.88, P = .004), and 2 years (1.66 vs 2.1%, OR 0.79, 95% CI 0.62-0.99, P = .049). Total surgical complications were significantly lower in the robotic-assisted cohort at 1 year (5.29 vs 6.16%, OR 0.85, 95% CI 0.74-0.98, P = .0205), but were similar at 90 days and 2 years. At 90 days, the rates of medical complications, including surgical site infections, pulmonary emboli, venous thromboemboli, and wound complications, were similar (all P > .05). The rates of periprosthetic joint infections, aseptic revision, periprosthetic fractures, and aseptic loosening were similar at all time points (all P > .05).

Conclusions

Patients who underwent robotic-assisted THA had lower rates of dislocation at 90 days, 1 year, and 2 years. This finding supports the use of robotic assistance in THA, though further research is needed to confirm and strengthen these findings.

Accuracy of robotic arm-assisted versus computed tomography-based navigation in total hip arthroplasty using the direct anterior approach: a retrospective study

BACKGROUND

A robotic arm-assisted and a computed tomography (CT)- based navigation system have been reported to improve the accuracy of component positioning in total hip arthroplasty (THA). However, no study has compared robotic arm-assisted THA (rTHA) to CT-based navigated THA (nTHA) concerning accuracy of cup placement and acetabular fractures using the direct anterior approach (DAA). This study aimed to compare the accuracy of cup placement and the presence of intraoperative acetabular fractures between rTHA and nTHA using DAA in the supine position.

METHODS

We retrospectively investigated 209 hips of 188 patients who underwent rTHA or nTHA using DAA (rTHA using the Mako system: 85 hips of 79 patients; nTHA: 124 hips of 109 patients). After propensity score matching for age and sex, each group consisted of 73 hips. We evaluated clinical and radiographic outcomes, comparing postoperative cup orientation and position, measured using a three-dimensional templating software, to preoperative CT planning. Additionally, we investigated the prevalence of occult acetabular fracture.

RESULTS

Clinical outcomes were not significantly different between the groups at 1 year postoperatively. The mean absolute error of cup orientation was significantly smaller in the rTHA group than in nTHA (inclination: 1.4° ± 1.2° vs. 2.7° ± 2.2°, respectively; p = 0.0001, anteversion: 1.5° ± 1.3° vs. 2.2° ± 1.7°, respectively; p = 0.007). The cases within an absolute error of 5 degrees in both RI and RA were significantly higher in the rTHA (97.3%) than in nTHA group (82.2%) (p = 0.003). The absolute error of the cup position was not significantly different between the two groups. The prevalence of occult acetabular fracture did not differ significantly between the two groups (rTHA: n = 0 [0%] vs. nTHA: n = 1 [1.4%]).

CONCLUSION

Cup placement using DAA in the supine position in rTHA was more accurate with fewer outliers compared to nTHA. Therefore, rTHA performed via DAA in a supine position would be useful for accurate cup placement.

Does Surgical Approach Affect Dislocation Rate After Total Hip Arthroplasty in Patients Who Have Prior Lumbar Spinal Fusion? A Retrospective Analysis of 16,223 Cases

BACKGROUND

Lumbar spinal fusion (LSF) is a risk factor for dislocation following total hip arthroplasty (THA). The effect of the surgical approach on this association has not been investigated. This study examined the association between the surgical approach and dislocation following THA in patients who had prior LSF.

METHODS

We retrospectively reviewed 16,223 primary elective THAs at our institution from June 2011 to September 2022. Patients who had LSF prior to THA were identified using International Classification of Diseases (ICD) codes. Patients were stratified by LSF history, surgical approach, and intraoperative robot or navigation use to compare dislocation rates. There were 8,962 (55.2%) posterior, 5,971 (36.8%) anterior, and 1,290 (8.0%) laterally based THAs. Prior LSF was identified in 323 patients (2.0%). Binary logistic regressions were used to assess the association of patient factors with dislocation risk.

RESULTS

There were 177 dislocations identified in total (1.1%). In nonadjusted analyses, the dislocation rate was significantly higher following the posterior approach among all patients (P = .003). Prior LSF was associated with a significantly higher dislocation rate in all patients (P < .001) and within the posterior (P < .001), but not the anterior approach (P = .514) subgroups. Multivariate regressions demonstrated anterior (OR [odds ratio] = 0.64, 95% CI [confidence interval] 0.45 to 0.91, P = .013), and laterally based (OR = 0.42, 95% CI 0.18 to 0.96, P = .039) approaches were associated with decreased dislocation risk, whereas prior LSF (OR = 4.28, 95% CI 2.38 to 7.69, P < .001) was associated with increased dislocation risk. Intraoperative technology utilization was not significantly associated with dislocation in the multivariate regressions (OR = 0.72, 95% CI 0.49 to 1.06, P = .095).

CONCLUSIONS

The current study confirmed that LSF is a significant risk factor for dislocation following THA; however, anterior and laterally based approaches may mitigate dislocation risk in this population. In multivariate analyses, including surgical approach, LSF, and several perioperative variables, intraoperative technology utilization was not found to be significantly associated with dislocation risk.

The bone trauma and soft-tissue injury classification system in total hip arthroplasty (BOSTI Hip)

Aims

The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system.

Methods

This study included 30 CO THAs versus 30 RO THAs performed by a single surgeon. Intraoperative photographs of the osseous acetabulum and periacetabular soft-tissues were obtained prior to implantation of the acetabular component, which were used to develop the proposed classification system. Interobserver and intraobserver variabilities of the proposed classification system were assessed.

Results

The BOne trauma and Soft-Tissue Injury classification system in total Hip arthroplasty (BOSTI Hip) grades osseous acetabular trauma and periarticular muscle damage during THA. The classification system has an interclass correlation coefficient of 0.90 (95% CI 0.86 to 0.93) for interobserver agreement and 0.89 (95% CI 0.84 to 0.93) for intraobserver agreement. RO THA was associated with improved BOSTI Hip scores (p = 0.002) and more pristine osseous surfaces in the anterior superior (p = 0.001) and posterior superior (p < 0.001) acetabular quadrants compared with CO THA. There were no differences between the groups in relation to injury to the gluteus medius (p = 0.084), obturator internus (p = 0.241), piriformis (p = 0.081), superior gamellus (p = 0.116), inferior gamellus (p = 0.132), quadratus femoris (p = 0.208), and vastus lateralis (p = 0.135), but overall combined muscle injury was reduced in RO THA compared with CO THA (p = 0.023).

Discussion

The proposed BOSTI Hip classification provides a reproducible grading system for stratifying iatrogenic bone trauma and soft-tissue injury during THA. RO THA was associated with improved BOSTI Hip scores, more pristine osseous acetabular surfaces, and reduced combined periarticular muscle injury compared with CO THA. Further research is required to understand if these intraoperative findings translate to differences in clinical outcomes between the treatment groups.

Opioid Use After Robotic-Assisted Versus Conventional Total Hip Arthroplasty: A National Database Analysis

BACKGROUND

In this study, we tested the null hypothesis that robotic-assisted total hip arthroplasty (THA) vs conventional THA was not associated with (1) the amount of postoperative opioid use and (2) the incidence of new, persistent opioid use.

MATERIALS AND METHODS

We used a large, national administrative database to identify patients 50 years and older undergoing primary robotic or conventional THA. Patients with hip fractures or a history of malignancy, hip infection, or opioid use disorder were excluded. Patients who filled an opioid prescription within 1 year to 30 days preoperatively or who underwent a subsequent procedure within 1 year after THA were excluded. Outcomes included the morphine milligram equivalents (MMEs) filled within the THA perioperative period and the incidence of new, persistent opioid use. Multivariable logistic regression models were used to evaluate associations between robotic-assisted THA and new, persistent opioid use, adjusting for age, sex, insurance plan, region, location of surgery, and comorbidities.

RESULTS

In the postoperative period, robotic-assisted THA, compared with conventional THA, was associated with a lower mean total MMEs filled per patient (452.2 vs 517.1; P<.001) and a lower mean MMEs per patient per day (71.53 vs 74.64; P<.001). Patients undergoing robotic-assisted THA had decreased odds of developing new, persistent opioid use compared with patients undergoing conventional THA (adjusted odds ratio, 0.82 [95% CI, 0.74-0.90]).

CONCLUSION

Robotic-assisted THA is associated with lower postoperative opioid use and a decreased odds of developing new, persistent opioid use compared with conventional THA. For the purposes of reducing opioid use, our results support the adoption of robotic-assisted THA. [Orthopedics. 2024;47(5):289-294.].

Fewer Dislocations After Total Hip Arthroplasty With Robotic Assistance or Fluoroscopic Guidance

BACKGROUND

Computer navigation and robotic assistance may reduce total hip arthroplasty (THA) dislocations by improving the accuracy and precision of component positioning. We investigated dislocation rates for THAs using conventional techniques, robotic assistance, and computer navigation, while controlling for surgical approach, dual mobility (DM) use, and fluoroscopic guidance.

METHODS

We reviewed 11,740 primary THAs performed between June 2016 and December 2022, including 5,873 conventional, 1,293 with robotic-arm assistance, and 4,574 with navigation. The approach was posterior in 6,580 (56.0%), anterior in 4,342 (37.0%), and lateral in 818 (7.0%). A DM was used in 10.4%. Fluoroscopy was used in 3,653 cases and only with the anterior approach. Multivariate analyses yielded odds ratios (OR) for dislocation and revision. Additional regression analyses for dislocation were performed for approach and DM.

RESULTS

Raw dislocation rates were as follows: conventional 1.2%, robotic 0.4%, navigation 0.9%, anterior with fluoroscopy 0.4%, anterior without fluoroscopy 2.3%, posterior 1.3%, and lateral 0.5%. Upon multivariate analysis, use of robotics was found to be associated with significantly reduced dislocation risk compared to conventional (OR: 0.3), as did anterior (OR: 0.6) compared to posterior approach; navigation and lateral approach were not found to be associated with a significant reduction in risk. For the anterior approach, multivariate analysis demonstrated that fluoroscopy significantly reduced dislocation risk (OR: 0.1), while DM, robotics, and navigation were not significant. For the posterior approach, the dislocation risk was lower with robotics than with conventional (OR: 0.2); the use of navigation or DM did not demonstrate a significant reduction in risk.

CONCLUSIONS

The use of robotics was associated with a reduction in dislocations for this cohort overall. Further, fluoroscopy in the anterior approach and robotic assistance in the posterior approach were both associated with decreased dislocation risk. The role of imageless computer navigation and DM implants requires further study.

Length of Stay and Discharge Disposition After Total Hip Arthroplasty: A Large Multicenter Propensity Matched Comparison of Robotic-Assisted and Manual Techniques

BACKGROUND

Robotic-arm assistance continues to gain popularity in total hip arthroplasty (THA) for its potential to improve component placement accuracy and patient outcomes. Nonetheless, there is limited data on the impact of robotic-assisted THA (RA-THA) on hospital length of stay (LOS) and discharge location. This study thus aimed to compare LOS, discharge location, and readmission rate for propensity-matched cohorts of RA-THA versus manual THA (M-THA).

METHODS

A retrospective review of a multi-hospital database was performed to identify patients who underwent THA between January 2016 and December 2021 from surgeons who performed both RA-THA and M-THA at 77 geographically diverse hospitals. The RA-THA and M-THA cohorts were 1-to-1 matched based on patient sex, age, and body mass index, resulting in 8,536 patients per cohort. Insurance type, LOS, same-day discharge, discharge disposition, and 90-day all-cause readmission rate were compared using Mann-Whitney U and Chi-square tests.

RESULTS

Average LOS was significantly shorter for RA-THA patients (1.39 ± 0.85 days) than for M-THA patients (1.48 ± 0.91 days, P < .001). Compared to 5.6% of M-THA patients, 5.3% of RA-THA patients underwent same-day discharge (P = .38). There were statistically significant differences in discharge disposition between cohorts, with more RA-THA cases discharged home without home healthcare compared to M-THA (47.9 versus 45.5%, P = .001) and fewer RA-THA cases discharged to a skilled nursing facility compared to M-THA (5.6 versus 6.9%, P = .001). The 90-day all-cause readmission rate for RA-THA cases was 3.0%, compared to 3.4% for M-THA cases (P = .26).

CONCLUSIONS

Compared to M-THA, RA-THA had a shorter average LOS, a similar percentage of patients with same-day discharge, fewer patients who had skilled nursing facility discharge, and a similar all-cause 90-day readmission rate. These results may be of interest to surgeons participating in bundled payment programs and engaging in cost savings.

Why robot-assisted total hip arthroplasty aborted: Chinese experience of four hundred and twenty nine consecutive cases

PURPOSE

Robot-assisted total hip arthroplasty (RA-THA) helps with precise orientation of the prosthesis, but some RA-THA procedures are aborted intraoperatively and are converted to manual total hip arthroplasty (THA). This study aimed to analyse why RA-THA is sometimes aborted intraoperatively and to make recommendations accordingly.

METHODS

A total of 429 consecutive Mako THA cases in our prospective database from August 2018 to June 2021 were included in our study. All robotic procedures aborted intraoperatively for any reason were recorded. The patients' demographics, diagnoses, and surgeons' information were included in the statistical analysis to pinpoint the risk factors for intraoperative robot to manual conversion.

RESULTS

Intraoperative RA-THA abortions occurred in 17 cases (3.96%) and the patients had to be converted to manual THA. The adverse events leading to intraoperative abortions included pelvic array loosening or malposition (5, 1.17%), inaccurate bone mapping or construction (6, 1.40%), inaccurate initial registration (4, 0.93%), and other reasons (2, 0.47%).

CONCLUSION

Robot-related adverse events could be found in all perioperative steps of RA-THA, and some of these events might result in intraoperative abortion. Complex hip disease was a statistically significant factor for an increased risk of intraoperative abortion of RA-THA. Standardized surgical procedures and preoperative assessments can be helpful in reducing the rate of RA-THA abortions.

Radiographic evaluation of robot-assisted versus manual total hip arthroplasty: a multicenter randomized controlled trial

BACKGROUND

The effectiveness of robot-assisted surgery remains contentious due to the lack of high-quality randomized controlled trials (RCTs) to elevate the level of evidence. We aimed to evaluate the postoperative radiographic outcomes of robot-assisted (RAS-THA) versus manual (M-THA) total hip arthroplasty.

METHODS

This multicenter RCT was performed from March 1, 2021 to December 1, 2021. Patients were randomly assigned to routine M-THA or to RAS-THA that used the TRex-RS orthopedic joint surgical navigation system. The primary outcome was to compare the acetabular component orientation, femoral stem alignment, femoral canal fill ratio, and leg length discrepancy between RAS-THA and M-THA using postoperative radiography. Subgroup analyses of the two groups stratified by surgical approach, gender, and BMI were also conducted.

RESULTS

Seventy-three participants were randomly allocated to the RAS-THA group, while seventy-two participants were assigned to the M-THA group. Compared to the M-THA group, the RAS-THA group exhibited less variability in the preoperative planning of the vertical center of rotation (VCOR; P < 0.001), demonstrated a significant advantage in femoral stem alignment (P = 0.004), and showed pronounced decreases in inequality and in the variability in leg length discrepancy (P < 0.001). There was no significant difference in the Lewinnek safe-zone ratio (P = 0.081) and the femoral canal fill ratio (P > 0.05) between the two groups. Further subgroup analysis also showed that the RAS-THA group had fewer horizontal center of rotation (HCOR) and leg length differences when stratified by surgical approach, gender, and overweight status.

CONCLUSION

This RCT found that, regardless of the surgical approach, gender, or body mass index, RAS-THA can effectively improve the postoperative VCOR and significantly reduce the variability of leg length difference. RAS-THA should be considered an effective method to enhance surgical precision by achieving less variability in challenging patients with leg length discrepancies.

TRIAL REGISTRATION

ChiCTR2100044124.

Robotic-assisted Total Hip Arthroplasty and Spinopelvic Parameters: A Review

Total hip arthroplasty (THA) is an effective treatment for osteoarthritis, and the popularity of the direct anterior approach has increased due to more rapid recovery and increased stability. Instability, commonly caused by component malposition, remains a significant concern. The dynamic relationship between the pelvis and lumbar spine, deemed spinopelvic motion, is considered an important factor in stability. Various parameters are used in evaluating spinopelvic motion. Understanding spinopelvic motion is critical, and executing a precise plan for positioning the implant can be difficult with manual instrumentation. Robotic and/or navigation systems have been developed in the effort to enhance THA outcomes and for implementing spinopelvic parameters. These systems can be classified into three categories: X-ray/fluoroscopy-based, imageless, and computed tomography (CT)-based. Each system has advantages and limitations. When using CT-based systems, preoperative CT scans are used to assist with preoperative planning and intraoperative execution, providing feedback on implant position and restoration of hip biomechanics within a functional safe zone developed according to each patient's specific spinopelvic parameters. Several studies have demonstrated the accuracy and reproducibility of robotic systems with regard to implant positioning and leg length discrepancy. Some studies have reported better radiographic and clinical outcomes with use of robotic-assisted THA. However, clinical outcomes comparable to those for manual THA have also been reported. Robotic systems offer advantages in terms of accuracy, precision, and potentially reduced rates of dislocation. Additional research, including conduct of randomized controlled trials, will be required in order to evaluate the long-term outcomes and cost-effectiveness of robotic-assisted THA.

Robot-Assisted Total Hip Arthroplasty Demonstrates Improved 90-Day Clinical and Patient-Reported Outcomes

Background

The utilization of technology, including robotics and computer navigation, in total hip arthroplasty (THA) has been steadily increasing; however, conflicting data exists regarding its effect on short-term clinical and patient-reported outcomes. Therefore, this study sought to explore the association between different surgical technologies and postoperative outcomes following THA.

Methods

We retrospectively reviewed 9892 primary THA cases performed by 62 surgeons from a single institution from September 2017 to November 2022. Three cohorts were created based on the utilization of technology: conventional (no technology), navigation, or robotics. Patient demographics, clinical outcomes, and patient-reported outcome measures were collected over the first 90 days following surgery. This data was compared using analysis of variance and multivariate logistic regressions. In total, 4275 conventional, 4510 navigation, and 1107 robotic cases were included in our analyses.

Results

The robotic cohort achieved a perfect Activity Measure for Post-Acute Care (AM-PAC) score earliest (0.1 days, P < .001). After adjusting for potential confounding variables, use of robotic assistance was associated with greater odds of achieving a perfect AM-PAC score on postoperative day 0 (odds ratio 1.6, P < .001) and greater odds of having length of stay shorter than 24 hours (odds ratio 2.3, P < .001) compared to no technology use in THA. Hip dysfunction and Osteoarthritis Outcome Score, Joint Replacement and Patient-Reported Outcomes Measurement Information System Pain Interference scores showed the greatest improvement in the robotic cohort at both 6 weeks and 3 months following surgery.

Conclusions

The present study demonstrates favorable clinical and patient-reported outcomes in the first 90 days following surgery for patients undergoing robot-assisted THA compared to conventional and navigation-assisted THA.

Robotics and Navigation Do Not Affect the Risk of Periprosthetic Joint Infection Following Primary Total Hip Arthroplasty: A Propensity Score-Matched Cohort Analysis

BACKGROUND

The use of computer navigation or robotic assistance during primary total hip arthroplasty (THA) has yielded numerous benefits due to more accurate component positioning. The utilization of these tools is generally associated with longer operative times and also necessitates additional surgical equipment and personnel in the operating room. Thus, the aim of this study was to evaluate the impact of technology assistance on periprosthetic joint infection (PJI) after primary THA.

METHODS

We retrospectively reviewed the records for 12,726 patients who had undergone primary THA at a single high-volume institution between 2018 and 2021. Patients were stratified by surgical technique (conventional THA, computer-navigated THA [CN-THA], or robotic-assisted THA [RA-THA]) and were matched 1:1 with use of propensity score matching. Univariate and logistic regression analyses were performed to compare the rates of PJI within 90 days postoperatively between the cohorts.

RESULTS

After propensity score matching, there were 4,006 patients in the THA versus RA-THA analysis (2,003 in each group) and 5,288 patients in the THA versus CN-THA analysis (2,644 in each group). CN-THA (p < 0.001) and RA-THA (p < 0.001) were associated with longer operative times compared with conventional THA by 3 and 11 minutes, respectively. The rates of PJI after conventional THA (0.2% to 0.4%) were similar to those after CN-THA (0.4%) and RA-THA (0.4%). On the basis of logistic regression, the development of PJI was not associated with the use of computer navigation (odds ratio [OR], 1.8 [95% confidence interval (CI), 0.7 to 5.3]; p = 0.232) or robotic assistance (OR, 0.9 [95% CI, 0.3 to 2.3]; p = 0.808).

CONCLUSIONS

Despite longer operative times associated with the use of computer navigation and robotic assistance, the use of these tools was not associated with an increased risk of PJI within 90 days after surgery.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

From past to digital time: Bibliometric perspective of worldwide research productivity on robotic and computer-assisted arthroplasty

Objective

The number of citations can be used as an impact marker of research work. This study aimed to determine and characterize the worldwide research productivity on robotic and computer-assisted arthroplasty.

Methods

All accessible publications from 1992 to 2023 on robotic and computer-assisted arthroplasty from Web of Science Core Collection (WOSCC) database were recorded in August 2024. The following aspects were retrieved: cited times, name of author, keywords, institution, country, year of publication, journal, title, topic, impact factor, and H-index. VOSviewer software and Microsoft Excel were conducted to make the bibliometric research visual. The nature of our study is a systematic study and was conducted in China.

Results

1061 articles were included in our study. The total cited times were 27,461 with the average number of 26. The most productive year was 2022, with a total of 158 publications. The United States contributed the highest number of articles (n = 389, 36.66%) and the Hospital for Special Surgery (n = 53, 5.00%) held the leading institution. "Orthopedics" became the dominant topic (n = 894, 84.26%) and the latest keywords "clinical outcomes", "acetabular cup placement", and "satisfaction" have mainly appeared since 2020.

Conclusions

Our analysis gives a comprehensive review of related articles on robotic and computer-assisted arthroplasty from past to future. The United States dominated studies of robotic and computer-assisted arthroplasty and a journal about arthroplasty was the most productive one. "Clinical outcomes", "Acetabular cup placement", and "Satisfaction" may become the future research hotspots.

Acetabular cup positioning in primary routine total hip arthroplasty-a review of current concepts and technologies

INTRODUCTION

Total hip arthroplasty (THA) has revolutionized the treatment of hip joint arthritis. With the increased popularity and success of the procedure, research has focused on improving implant survival and reducing surgical complications. Optimal component orientation has been a constant focus with various philosophies proposed. Regardless of the philosophy, achieving an accurate acetabular position for each clinical scenario is crucial. In this paper, we review the recent developments in improving the accuracy and ideal positioning of the acetabular cup in routine primary THA.

METHODOLOGY

A review of the recent scientific literature for acetabular cup placement in primary THA was performed, with available evidence for safe zones, spinopelvic relationship, preoperative planning, patient-specific instrumentation, navigation THA and robotic THA.

CONCLUSION

Though the applicability of Lewinnek safe zones has been questioned with an improved understanding of spinopelvic relationships, its role remains in positioning the acetabular cup in a patient with normal spinopelvic alignment and mobility. Evaluation of spinopelvic relationships and accordingly adjusting acetabular anteversion and inclination can significantly reduce the incidence of dislocation in patients with a rigid spine. In using preoperative radiography, the acetabular inclination, anteversion and intraoperative pelvic position should be evaluated. With improving technology and the advent of artificial intelligence, superior and more accurate preoperative planning is possible. Patient-specific instrumentation, navigated and robotic THA have been reported to improve accuracy in acetabular cup positioning as decided preoperatively but any significant clinical advantage over conventional THA is yet to be elucidated.

The invasiveness of robot-assisted total hip replacement is similar to that of conventional surgery

Robot-assisted total hip arthroplasty (R-THA) is increasingly being performed throughout the world. The invasiveness of this operation is unknown. We retrospectively reviewed the cohort of consecutive osteonecrosis of the femoral head (ONFH) patients who received primary R-THA or manual THA (M-THA) from January 2020 to January 2022 in our institution. One experienced surgeon performed all procedures. We calculated the propensity score to match similar patients in different groups by multivariate logistic regression analysis for each patient. We included confounders consisting of age, sex, body mass index (BMI), and operation time. Preoperative serum markers and Harris hip scores (HHS), postoperative serum markers at first day and third day, complications rate, postoperative HHS and Forgotten Joint Score (FJS) at 6 months after surgery of different cohorts were compared. We analyzed 218 ONFH patients treated with THA (98 R-THA patients, and 120 M-THA patients). After propensity score matching, we generated cohorts of 95 patients in R-THA and M-THA groups. We found no significant difference in preoperative serum markers and HHS. In the R-THA cohort, the PLT count was significantly lower on the postoperative day 1 (192.36 ± 41.72 × 109/L Vs 210.47 ± 72.85 × 109/L, p < 0.05). The Hb level was significantly lower on the postoperative third day in the R-THA cohort (98.52 ± 12.99 g/L Vs 104.74 ± 13.15 g/L, p < 0.05). There was no significant difference in the other serum markers between the cohorts on postoperative day 1 and 3 (p > 0.05). The FJS was significantly higher in the R-THA than M-THA group (p = 0.01). There was no significant difference in the postoperative HHS or complication rate between the groups (p > 0.05). The R-THA is not associated with a serious invasiveness compared to M-THA. Patients who underwent R-THA had a better early function compared to those who underwent M-THA.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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 Top Three Burning Questions in Total Hip Arthroplasty

Total hip arthroplasty (THA) for end-stage osteoarthritis is one of the most effective surgical treatments in medicine. Impressive outcomes have been well documented in the literature with patients gaining ambulation and recovery of hip joint function. Nevertheless, there are still debatable issues and controversies that the orthopedic community has not been able to provide a definitive answer for. This review is focused on the current three most debatable issues surrounding the THA procedure: (1) new cutting-edge technology, (2) spinopelvic mobility, and (3) fast-track protocols. The scope of the herein narrative review is to analyze the debatable issues surrounding the three aforementioned topics and conclude the best contemporary clinical approaches regarding each issue.

Status of robot-assisted artificial total joint arthroplasty in China: a cross-sectional survey of joint surgeons

PURPOSE

The purpose of this study is to report on the use of Robotic-assisted total joint arthroplasty (RA-TJA) in China as well as the experience and expectations of Chinese doctors regarding this technology.

METHOD

A self-administered questionnaire was used to assess the current status of RA-TJA in China, the practical experience and suggestions for improvement of the technology by joint surgeons who have performed RA-TJA, and the interest and expectations of orthopaedic surgeons who have not used RA-TJA. The questionnaire was administered to all the physicians of the Chinese Association of Orthopedic Surgeons (CAOS).

RESULT

A total of 372 qualified questionnaires were generated, among which 28% (n = 104) of the respondents had performed RA-TJA, among those who had performed RA-TJA. When asked how helpful the joint replacement robot was actually/expected to be, there was no significant difference between the expected and actual experience of nonusers and users (p ≥ 0.05); the biggest disadvantage of the current development of RA-TJA was perceived as additional charges to the patient by those who had used it, while those who had not used it perceived it as a limitation of their hospital, both of which were significant differences. Most respondents in both groups (used: 94.2%; not used: 91.4%) were confident in the clinical development of the joint replacement robot.

CONCLUSION

This survey provides cross-sectional data on the current status of Chinese joint surgeons using or not using robots in their daily clinical practice. Improving surgical precision was the consensus of most respondents, while high surgical costs and limitations of hospital conditions were barriers to its development in China.

Epidemiology of total hip arthroplasty: demographics, comorbidities and outcomes

BACKGROUND

Primary THA (THA) is a successful procedure for end-stage hip osteoarthritis. In the setting of a failed THA, revision total hip arthroplasty (rTHA) acts as a salvage procedure. This procedure has increased risks, including sepsis, infection, prolonged surgery time, blood loss, and increased length of stay. Increasing focus on understanding of demographics, comorbidities, and inpatient outcomes can lead to better perioperative optimization and post-operative outcomes. This epidemiological registry study aimed to compare the demographics, comorbidity profiles, and outcomes of patients undergoing THA and rTHA.

METHODS

A retrospective review of discharge data reported from 2006 to the third quarter of 2015 using the National Inpatient Sample registry was performed. The study included adult patients aged 40 and older who underwent either THA or rTHA. A total of 2,838,742 THA patients and 400,974 rTHA patients were identified.

RESULTS

The primary reimbursement for both THA and rTHA was dispensed by Medicare at 53.51% and 65.36% of cases respectively. Complications arose in 27.32% of THA and 39.46% of rTHA cases. Postoperative anemia was the most common complication in groups (25.20% and 35.69%). Common comorbidities in both groups were hypertension and chronic pulmonary disease. rTHA indications included dislocation/instability (21.85%) followed by mechanical loosening (19.74%), other mechanical complications (17.38%), and infection (15.10%).

CONCLUSION

Our data demonstrated a 69.50% increase in patients receiving THA and a 28.50% increase in rTHA from the years 2006 to 2014. The data demonstrated 27.32% and 39.46% complication rate with THA and rTHA, with postoperative anemia as the most common cause. Common comorbidities were hypertension and chronic pulmonary disease. Future analyses into preoperative optimizations, such as prior consultation with medical specialists or improved primary hip protocol, should be considered to prevent/reduce postoperative complications amongst a progressive expansion in patients receiving both THA and rTHA.

Is Robotic-Assisted Technology Still Accurate in Total Hip Arthroplasty for Fibrous-Fused Hips?

BACKGROUND

Total hip arthroplasty (THA) for fibrous-fused hips is technically demanding. This study aimed to evaluate the precision and accuracy, as well as the rate of conversion of robotic-assisted THA in such difficult patients.

METHODS

We retrospectively analyzed 67 patients (84 hips) who underwent THA with fibrous-fused hips between August 2018 and June 2021 at our institution. Demographics, acetabular cup positioning, leg-length discrepancies, and postoperative Harris hip scores were recorded for all patients. Thirty-six patients (44 hips) who underwent robotic-assisted THA and 31 patients (40 hips) who underwent manual THA were enrolled in this study.

RESULTS

The robot accurately executed the preoperative plan, and there were no statistically significant differences between the preoperative planned anteversion, inclination, and postoperative measurements. In the robotic group, the percentage of acetabular cups in the safe zone was significantly higher than in the manual group (87.2 versus 55%, respectively, P = .042). The rate of conversion to manual THA for various reasons in the robotic-assisted THA group was 11.4% (5/44). Compared with manual THA, the mean increase in operative time for conversion from robotic-assisted to manual THA was 24 min (P < .001).

CONCLUSION

In patients who have fibrous-fused hips, preoperative planning can be accurately executed by robotic-assisted technology. Compared with manual THA, robotic-assisted THA had a remarkable advantage in improving the frequency of achieving cup positioning within the target zone. Overall, robotic-assisted technology was helpful in such difficult cases, and the approximately 11.4% of cases converted to manual THA are reminders that surgeons should be thoroughly prepared preoperatively.

Total Hip Arthroplasty Imageless Navigation Does Not Reduce 90-Day Adverse Events or Five-Year Revisions in a Large National Cohort

BACKGROUND

Computer navigation is an increasingly utilized technology that is considered with total hip arthroplasty (THA). However, the evidence to support this practice is mixed. The current study leveraged a large national administrative database to compare 90-day adverse events as well as 5-year all-cause revision and dislocation rates following THA performed with and without imageless navigation.

METHODS

From 2010 to 2020, a large national database was queried for THA cases performed for osteoarthritis. Cases with or without imageless navigation were matched at 1:4 based on age, sex, and Elixhauser Comorbidity Index (ECI) score. Ninety-day adverse events were assessed and compared with multivariate analyses. Five-year incidence of revision and dislocation were also assessed between cohorts.

RESULTS

Use of THA imageless navigation increased from 2010 (2.5% of cases) to 2020 (5.5% of cases; P < .001). After matching, 11,990 THA patients with navigation and 47,948 without navigation were identified. Overall, 90-day adverse events were observed in 7.0% of the population. Multivariate analysis controlling for age, sex, and ECI demonstrated a difference in only one 90-day adverse event; wound dehiscence, which had higher odds in the navigation group (odds ratio, 1.60, P < .001). At 5 years, revisions for the navigated group were higher (4.4 versus 3.6%: P = .006), while dislocations were not significantly different.

CONCLUSION

THA imageless navigation was not found to be associated with improved 90-day postoperative adverse events or differences in the 5-year rates of revision or dislocation. The current data were unable to identify clear advantages of this evolving technology for primary THA.

Robotic-Arm-Assisted Total Hip Arthroplasty: A Review of the Workflow, Outcomes and Its Role in Addressing the Challenge of Spinopelvic Imbalance

Robotic-arm-assisted total hip arthroplasty (RoTHA) offers the opportunity to improve the implant positioning and restoration of native hip mechanics. The concept of individualised, functional implant positioning and how it relates to spinopelvic imbalance is an important yet rather novel consideration in THA. There is mounting evidence that a significant percentage of dislocations occur within the perceived "safe zones"; hence, in the challenging subset of patients with a stiff spinopelvic construct, it is imperative to employ individualised component positioning based on the patients' phenotype. Restoring the native centre of rotation, preserving offset, achieving the desired combined anteversion and avoiding leg length inequality are all very important surgeon-controlled variables that have been shown to be associated with postoperative outcomes. The latest version of the software has a feature of virtual range of motion (VROM), which preoperatively identifies potential dynamic causes of impingement that can cause instability. This review presents the workflow of RoTHA, especially focusing on pragmatic solutions to tackle the challenge of spinopelvic imbalance. Furthermore, it presents an overview of the existing evidence concerning RoTHA and touches upon future direction.