Robotic arm-assisted conversion of unicompartmental knee arthroplasty to total knee arthroplasty.

Aims: Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up. Methods: This prospective study included 16 patients undergoing robotic arm-assisted revision of UKA to TKA versus 35 matched patients receiving robotic arm-assisted primary TKA. In all study patients, the following data were recorded: operating time, polyethylene liner size, change in haemoglobin concentration (g/dl), length of inpatient stay, postoperative complications, and hip-knee-ankle (HKA) alignment. All procedures were performed using the principles of functional alignment. At most recent follow-up, range of motion (ROM), Forgotten Joint Score (FJS), and Oxford Knee Score (OKS) were collected. Mean follow-up time was 21 months (6 to 36). Results: There were no differences between the two treatment groups with regard to mean change in haemoglobin concentration (p = 0.477), length of stay (LOS, p = 0.172), mean polyethylene thickness (p = 0.065), or postoperative complication rates (p = 0.295). At the most recent follow-up, the primary robotic arm-assisted TKA group had a statistically significantly improved OKS compared with the revision UKA to TKA group (44.6 (SD 2.7) vs 42.3 (SD 2.5); p = 0.004) but there was no difference in the overall ROM (p = 0.056) or FJS between the two treatment groups (86.1 (SD 9.6) vs 84.1 (4.9); p = 0.439). Conclusion: Robotic arm-assisted revision of UKA to TKA was associated with comparable intraoperative blood loss, early postoperative rehabilitation, functional outcomes, and complications to primary robotic TKA at short-term follow-up. Robotic arm-assisted surgery offers a safe and reproducible technique for revising failed UKA to TKA.

Strong Correlation Between Standing Long-Leg Radiographs and CT Scans in Measuring Coronal Knee Alignment.

BACKGROUND: The objective of this study was to evaluate the correlation in measurements of the lower-limb coronal alignment between long-leg radiographs (LLRs) and computed tomography (CT) scanograms that were made during preoperative planning for robotic-arm-assisted knee arthroplasty. On the basis of published evidence demonstrating a good correlation between these imaging modalities in measuring the lower-limb mechanical axis, we hypothesized that there would be no significant differences between the 2 in the present study. METHODS: This multicenter cohort study across 3 tertiary centers included 300 patients undergoing primary robotic-arm-assisted total knee arthroplasty (TKA) or unicompartmental knee arthroplasty (UKA) for whom LLRs and CT scanograms were available preoperatively. The study involved measuring the medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), hip-knee-ankle angle (HKA), joint line obliquity (JLO), joint-line convergence angle (JLCA), and arithmetic HKA (aHKA). The aHKA represents a method for estimating constitutional alignment using angles that are unaffected by joint-space narrowing. RESULTS: Strong correlations (p < 0.001) between the imaging modalities were found for the HKA (correlation coefficient, 0.912), aHKA (0.883), MPTA (0.820), LDFA (0.871), and JLO (0.778). A weaker correlation was observed for the JLCA in valgus knees as compared with varus knees (Spearman coefficients, 0.412 and 0.518, respectively). Regression models demonstrated that the degree of agreement was associated with the preoperative intra-articular deformity and the positioning of the lower limb during the CT scan (i.e., the lower-limb rotational angle). An initial JLCA within ±5° was associated with higher agreement. CONCLUSIONS: We observed a strong correlation between LLRs and CT scanograms that were made during the preoperative planning stage of robotic-arm-assisted knee arthroplasty, implying that CT scanograms can reliably be utilized to estimate the coronal alignment of the knee, potentially replacing the need for LLRs. Nevertheless, to attain a higher degree of agreement, it is crucial to ensure appropriate radiographic positioning of the lower limb. Additionally, surgeons must remain vigilant regarding potential discrepancies in cases involving substantial deformities. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Gender does not influence outcomes and complications in medial unicompartmental knee arthroplasty.

PURPOSE: The impact of gender on the outcomes of unicompartmental knee arthroplasty (UKA) remains a topic of active discussion with limited exploration thus far. The study aims to elucidate the gender effect on clinical outcomes, complications, pre- and postoperative radiological outcomes following the implantation of a medial UKA at mid-term follow-up in a large section of patients. METHODS: This was a single-centre, retrospective cohort study encompassing patients undergoing medial UKA between 2011 and 2019. The International Knee Society (IKS) Knee and Function score, patient satisfaction, complications, revisions, pre- and postoperative radiological outcomes (coronal plane alignment, femoral and tibial component positioning, posterior tibial slope) were evaluated. Survival rate at the time of the last follow-up was also recorded. RESULTS: Of the 366 knees that met the inclusion criteria, 10 were lost to follow-up, accounting for a 2.7% loss. Mean follow-up was 5.2 ± 2 years [2.1-11.3]. Out of the total population, 205 patients were females (57.6%, 205/356) and 151 were males (42.4%, 151/356). Men exhibited superior pre- and postoperative IKS function scores (p = 0.017). However, no significant differences were observed between women and men regarding improvements of IKS Knee and Function scores, radiographic outcomes and implant survivorship. CONCLUSION: At a mean follow-up of 5 years, this study revealed no significant impact of gender on clinical outcomes and complications in patients undergoing medial UKA. Furthermore, no significant differences were evident in radiographic outcomes, implant positioning and knee phenotype. LEVEL OF EVIDENCE: Level III.

Ten-year results from the UK National Ligament Registry: Patient characteristics and factors predicting nonresponders for completion of outcome scores.

PURPOSE: The aim of this study was to report the demographic and mechanism of injury data in the UK National Ligament Registry (NLR) at 10 years and determine factors leading to poor compliance with completion of Patient-Reported Outcome Scores (PROMs). METHODS: A retrospective review was performed for prospectively collected data on the NLR between January 2013 and December 2022. All patients who underwent primary anterior cruciate ligament reconstruction (ACLR) were included. Patient demographics, mechanism of injury and patient compliance with completing PROMs were analysed. Patient characteristics were further analysed in relation to compliance with completing the different PROMs at the predefined time points. Patients were identified as nonresponders if they had not completed either 1- or 2-year postoperative Knee injury and Osteoarthritis Outcome Score (KOOS). RESULTS: A total of 17,492 patients were included in this study. The average age for patients undergoing ACLR between 2013 and 2022 was 29.4 (SD, 10.3). Seventy percent were men and 30% women. Football was the most common activity associated with an ACL injury. Patient compliance with recording PROMs was 55% preoperatively and 37%, 32% and 24% at 1-, 2- and 5-year postoperative follow-up, respectively. Nonresponders represented 54% of eligible patients. Multivariate analyses showed that sex, age, smoking, time interval between injury and surgery and low socioeconomic status were associated with low compliance with postoperative PROM completion (p < 0.001). CONCLUSION: This study reports the demographic characteristics for patients on the NLR since 2013. Male sex, young age, increased waiting time between injury and surgery, smoking and lower socioeconomic class were predictors of low compliance with completion of postoperative PROMs on the UK NLR. Understanding the factors that affect patient compliance with PROMs improves our ability to provide targeted interventions and information to specific patient populations with the aim of enhancing inclusiveness and representation of population in the registry. LEVEL OF EVIDENCE: Level III.

A prospective randomized controlled trial comparing CT-based planning with conventional total hip arthroplasty versus robotic arm-assisted total hip arthroplasty.

Aims: Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA. Methods: This prospective randomized controlled trial (RCT) included 60 patients with symptomatic hip osteoarthritis undergoing conventional THA (CO THA) versus robotic arm-assisted THA (RO THA). Patients in both arms underwent pre- and postoperative CT scans, and a patient-specific plan was created using the robotic software. The COR, combined offset, acetabular orientation, and leg length discrepancy were measured on the pre- and postoperative CT scanogram at six weeks following surgery. Results: There were no significant differences for any of the baseline characteristics including spinopelvic mobility. The absolute error for achieving the planned horizontal COR was median 1.4 mm (interquartile range (IQR) 0.87 to 3.42) in RO THA versus 4.3 mm (IQR 3 to 6.8; p < 0.001); vertical COR mean 0.91 mm (SD 0.73) in RO THA versus 2.3 mm (SD 1.3; p < 0.001); and combined offset median 2 mm (IQR 0.97 to 5.45) in RO THA versus 3.9 mm (IQR 2 to 7.9; p = 0.019). Improved accuracy was observed with RO THA in achieving the desired acetabular component positioning (root mean square error for anteversion and inclination was 2.6 and 1.3 vs 8.9 and 5.3, repectively) and leg length (mean 0.6 mm vs 1.4 mm; p < 0.001). Patient-reported outcome measures were comparable between the two groups at baseline and one year. Participants in the RO THA group needed fewer physiotherapy sessions postoperatively (median six (IQR 4.5 to 8) vs eight (IQR 6 to 11; p = 0.005). Conclusion: This RCT suggested that robotic-arm assistance in THA was associated with improved accuracy in restoring the native COR, better preservation of the combined offset, leg length correction, and superior accuracy in achieving the desired acetabular component positioning. Further evaluation through long-term and registry data is necessary to assess whether these findings translate into improved implant survival and functional outcomes.

Factors associated with decreased length of stay following robotic arm-assisted and conventional total hip arthroplasty.

Aims: Postoperative length of stay (LOS) and discharge dispositions following arthroplasty can be used as surrogate measurements for improvements in patients' pathways and costs. With the increasing use of robotic technology in arthroplasty, it is important to assess its impact on LOS. The aim of this study was to identify factors associated with decreased LOS following robotic arm-assisted total hip arthroplasty (RO THA) compared with the conventional technique (CO THA). Methods: This large-scale, single-institution study included 1,607 patients of any age who underwent 1,732 primary THAs for any indication between May 2019 and January 2023. The data which were collected included the demographics of the patients, LOS, type of anaesthetic, the need for treatment in a post-anaesthesia care unit (PACU), readmission within 30 days, and discharge disposition. Univariate and multivariate logistic regression models were used to identify factors and the characteristics of patients which were associated with delayed discharge. Results: The multivariate model identified that age, female sex, admission into a PACU, American Society of Anesthesiologists grade > II, and CO THA were associated with a significantly higher risk of a LOS of > two days. The median LOS was 54 hours (interquartile range (IQR) 34 to 78) in the RO THA group compared with 60 hours (IQR 51 to 100) in the CO THA group (p < 0.001). The discharge dispositions were comparable between the two groups. A higher proportion of patients undergoing CO THA required PACU admission postoperatively, although without reaching statistical significance (7.2% vs 5.2%, p = 0.238). Conclusion: We found that among other baseline characteristics and comorbidities, RO THA was associated with a significantly shorter LOS, with no difference in discharge destination. With the increasing demand for THA, these findings suggest that robotic assistance in THA could reduce costs. However, randomized controlled trials are required to investigate the cost-effectiveness of this technology.

The Value of Computed Tomography Scan in Three-dimensional Planning and Intraoperative Navigation in Primary Total Hip Arthroplasty.

Total hip arthroplasty (THA) is a frequently performed procedure; the objective is restoration of native hip biomechanics and achieving functional range of motion (ROM) through precise positioning of the prosthetic components. Advanced three-dimensional (3D) imaging and computed tomography (CT)-based navigation are valuable tools in both the preoperative planning and intraoperative execution. The aim of this study is to provide a thorough overview on the applications of CT scans in both the preoperative and intraoperative settings of primary THA. Preoperative planning using CT-based 3D imaging enables greater accuracy in prediction of implant sizes, leading to enhancement of surgical workflow with optimization of implant inventory. Surgeons can perform a more thorough assessment of posterior and anterior acetabular wall coverage, acetabular osteophytes, anatomical landmarks, and thus achieve more functional implant positioning. Intraoperative CT-based navigation can facilitate precise execution of the preoperative plan, to attain optimal positioning of the prosthetic components to avoid impingement. Medial reaming can be minimized preserving native bone stock, which can enable restoration of femoral, acetabular, and combined offsets. In addition, it is associated with greater accuracy in leg length adjustment, a critical factor in patients' postoperative satisfaction. Despite the higher costs and radiation exposure, which currently limits its widespread adoption, it offers many benefits, and the increasing interest in robotic surgery has facilitated its integration into routine practice. Conducting additional research on ultra-low-dose CT scans and examining the potential for translation of 3D imaging into improved clinical outcomes will be necessary to warrant its expanded application.

Adapting hip arthroplasty practices during the COVID-19 pandemic: Assessing the impact of outpatient care sudden increase on early complications and clinical outcomes.

INTRODUCTION: The COVID-19 pandemic has significantly affected access to timely care for patients with hip osteoarthritis requiring total hip replacement (THR). This study aimed to assess the changes in surgical activity, outpatient treatment, length of stay (LOS), discharge destinations, readmission rates, clinical outcomes, and patient satisfaction before and after the pandemic at our institution. MATERIALS AND METHODS: This retrospective study encompassed patients undergoing primary THR through the direct anterior approach at a single university hospital. Data on demographic characteristics, surgical technique, perioperative management, LOS, discharge destinations, complications, and clinical outcomes were collected. Furthermore, a comparative analysis between the pre-pandemic (2019) and post-pandemic (2022) periods was conducted. RESULTS: There was a 14% increase in surgical activity post-pandemic, with 214 patients undergoing surgery in 2019 versus 284 in 2022. The percentage of patients managed as outpatients significantly increased from 0.5% in 2019 to 29.6% in 2022 (p < 0.001). LOS decreased from 2.7 ± 1 [0-8] days to 1.4 ± 1.1 [0-12] days (p < 0.001), and the rate of discharge to rehabilitation centres declined from 21.5% to 8.8% (p < 0.001). No significant increase in the readmission rates was observed (1.4% in both periods). At two months postoperatively, the mean HHS and satisfaction rates were comparable between the two groups (p = 1 and p = 0.73, respectively). DISCUSSION: Despite the challenges posed by the COVID-19 pandemic, surgical activity at our institution demonstrated an increase compared to the pre-pandemic levels by expanding outpatient care, reducing LOS, and increasing rates of home discharges. Importantly, these changes did not adversely affect rehospitalization rates or early clinical outcomes. LEVEL OF EVIDENCE: IV.

Unveiling the potential of artificial intelligence in orthopaedic surgery.

Artificial intelligence is paving the way in contemporary medical advances, with the potential to revolutionise orthopaedic surgical care. By harnessing the power of complex algorithms, artificial intelligence yields outputs that have diverse applications including, but not limited to, identifying implants, diagnostic imaging for fracture and tumour recognition, prognostic tools through the use of electronic medical records, assessing arthroplasty outcomes, length of hospital stay and economic costs, monitoring the progress of functional rehabilitation, and innovative surgical training via simulation. However, amid the promising potential and enthusiasm surrounding artificial intelligence, clinicians should understand its limitations, and caution is needed before artificial intelligence-driven tools are introduced to clinical practice.

Robotic-arm assisted total knee arthroplasty is associated with comparable functional outcomes but improved forgotten joint scores compared with conventional manual total knee arthroplasty at five-year follow-up.

PURPOSE: This study reports the five-year functional outcomes from a prospective cohort study comparing robotic-arm assisted total knee arthroplasty (RO TKA) versus conventional manual total knee arthroplasty (CO TKA). METHODS: This prospective single-surgeon study included 120 patients with symptomatic end-stage knee arthritis undergoing primary TKA. This included 60 consecutive patients undergoing CO TKA followed by 60 consecutive patients undergoing RO TKA using a semi-automated robotic device. Study patients were reviewed at one, two, and five years after surgery and the following outcomes recorded: The University of California at Los Angeles activity-level (UCLA), Knee Society Score (KSS), Oxford Knee Score (OKS) Forgotten Joint Score (FJS), and any complications. RESULTS: There were no statistical differences between RO TKA and CO TKA in the median UCLA score (p = N.S), median KSS (p = N.S), and median OKS (p = N.S) at five-year follow-up. RO-TKA was associated with statistically significant improvements in the FJS at one (p = 0.001), two (p = 0.003), and five (p = 0.025) years of follow-up compared with CO TKA. There was no statistical difference in the incidence of knee stiffness requiring manipulation under anesthesia between the two treatment groups (p = N.S). CONCLUSION: Patients in both treatment groups had excellent functional outcomes with comparable patient reported outcomes at five-year follow-up. RO TKA was associated with statistically significant improvements in the FJS compared with CO TKA, but these differences did not reach the minimal clinically important difference at any follow-up interval. There was no overall difference in complications between the two treatment groups at five-year follow-up. LEVEL OF EVIDENCE: II (Prospective cohort study).

Telehealth for a better service delivery in orthopaedic surgery.

Telehealth has the potential to change the way we approach patient care. From virtual consenting to reducing carbon emissions, costs, and waiting times, it is a powerful tool in our clinical armamentarium. There is mounting evidence that remote diagnostic evaluation and decision-making have reached an acceptable level of accuracy and can safely be adopted in orthopaedic surgery. Furthermore, patients' and surgeons' satisfaction with virtual appointments are comparable to in-person consultations. Challenges to the widespread use of telehealth should, however, be acknowledged and include the cost of installation, training, maintenance, and accessibility. It is also vital that clinicians are conscious of the medicolegal and ethical considerations surrounding the medium and adhere strictly to the relevant data protection legislation and storage framework. It remains to be seen how organizations harness the full spectrum of the technology to facilitate effective patient care.

Artificial intelligence in orthopaedic surgery.

The use of artificial intelligence (AI) is rapidly growing across many domains, of which the medical field is no exception. AI is an umbrella term defining the practical application of algorithms to generate useful output, without the need of human cognition. Owing to the expanding volume of patient information collected, known as 'big data', AI is showing promise as a useful tool in healthcare research and across all aspects of patient care pathways. Practical applications in orthopaedic surgery include: diagnostics, such as fracture recognition and tumour detection; predictive models of clinical and patient-reported outcome measures, such as calculating mortality rates and length of hospital stay; and real-time rehabilitation monitoring and surgical training. However, clinicians should remain cognizant of AI's limitations, as the development of robust reporting and validation frameworks is of paramount importance to prevent avoidable errors and biases. The aim of this review article is to provide a comprehensive understanding of AI and its subfields, as well as to delineate its existing clinical applications in trauma and orthopaedic surgery. Furthermore, this narrative review expands upon the limitations of AI and future direction.

The impact of the menstrual cycle on orthopaedic sports injuries in female athletes.

There is a disparity in sport-related injuries between sexes, with females sustaining non-contact musculoskeletal injuries at a higher rate. Anterior cruciate ligament ruptures are between two and eight times more common than in males, and females also have a higher incidence of ankle sprains, patellofemoral pain, and bone stress injuries. The sequelae of such injuries can be devastating to an athlete, resulting in time out of sport, surgery, and the early onset of osteoarthritis. It is important to identify the causes of this disparity and introduce prevention programmes to reduce the incidence of these injuries. A natural difference reflects the effect of reproductive hormones in females, which have receptors in certain musculoskeletal tissues. Relaxin increases ligamentous laxity. Oestrogen decreases the synthesis of collagen and progesterone does the opposite. Insufficient diet and intensive training can lead to menstrual irregularities, which are common in female athletes and result in injury, whereas oral contraception may have a protective effect against certain injuries. It is important for coaches, physiotherapists, nutritionists, doctors, and athletes to be aware of these issues and to implement preventive measures. This annotation explores the relationship between the menstrual cycle and orthopaedic sports injuries in pre-menopausal females, and proposes recommendations to mitigate the risk of sustaining these injuries.

Combination of a High Residual Varus and Joint-Line Lowering Strongly Increases the Risk of Early Implant Failure in Medial Unicompartmental Knee Arthroplasty.

BACKGROUND: Outliers in implant positioning, malalignment, and joint line height change are risk factors for unicompartmental knee arthroplasty (UKA) failure. However, their relationships and patterns in large datasets remain unexplored. This study assessed medial UKA survival in a large cohort and explored associated risk factors. METHODS: This was a retrospective cohort study on medial UKA patients (2011 to 2019). Radiological outcomes included tibial implant positioning in the coronal plane, posterior tibial slope, residual knee deformity, and joint line restitution. Survival rate at last follow-up was recorded. Multinomial logistic regression analyzed risk factors, incorporating demographic and univariate analysis data. RESULTS: Three hundred and sixty-six knees met inclusion criteria, with 10 lost to follow-up (2.7%). Mean follow-up was 61.3 months [24.1 to 135.1]. 5- and 10-year implant survival rates were 92% ± 1.6 and 88.4% ± 3.8, respectively. Multivariate analysis identified post-operative hip-knee-ankle angle (HKA) ≤ 175° (OR = 5.30 [1.64 to 17.13], P = .005) and joint line lowering ≥2 mm (OR = 8.86 [2.06 to 38.06]) as significant risk factors for tibial implant failure. Their combination carried a significantly high risk of failure (OR = 10.3 [3.1 to 34.3]). Post-operative HKA < 175° was common in knees with pre-operative HKA < 172°. CONCLUSION: This study reports encouraging 5- and 10-year survival outcomes for medial UKA. Tibial loosening was the main reason for revision. Patients with joint line lowering ≥ 2 mm and post-operative HKA ≤ 175° were at high risk of tibial implant failure. Surgeons should carefully restore the joint line in cases of pre-operative HKA < 172°.

Patellofemoral Arthroplasty Is an Efficient Strategy for Isolated Patellofemoral Osteoarthritis with or without Robotic-Assisted System.

There is relative paucity in the literature concerning outcomes after robotic-assisted Patellofemoral Arthroplasty (PFA). The aims were (1) to evaluate outcomes in patients undergoing PFA with inlay or onlay components, with or without robotic arm assistance and (2) to identify risk factors of poor outcomes after PFA. This retrospective study included 77 PFA for isolated patellofemoral joint osteoarthritis, assigned to three groups (18 conventional technique, 17 image-free robotic-assisted system and 42 image-based robotic-assisted system). The demographic data were comparable between the three groups. The clinical outcomes assessed were: Visual Analogue Scale, Knee Society Score, Kujala score and satisfaction rate. The radiological measures were: Caton Deschamps index, patellar tilt and frontal alignment of the trochlea. Functional outcomes, satisfaction rate and residual pain were comparable between the three groups. Patellar tilt improvement was superior when a robotic device was used (either image-based or image-free) compared to the conventional technique. There were three revisions (3.9%) at the last follow-up related to femorotibial osteoarthritis progression. Multivariate analysis found no significant risk factors for poor outcomes, with respect to the surgical technique or implant design. Functional outcomes and revisions rate after PFA were comparable between the surgical techniques and implants. Robotic-assisted systems were associated with a superior improvement of the patellar tilt compared to the conventional technique.

Patient-Reported Outcome Measures in Conventional Total Hip Arthroplasty Versus Robotic-Arm Assisted Arthroplasty: A Prospective Cohort Study With Minimum 3 Years' Follow-Up.

BACKGROUND: Robotic-arm assisted total hip arthroplasty (RO THA) has been shown to improve the accuracy of component positioning compared with conventional total hip arthroplasty (CO THA). This study reports Patient-Reported Outcome Measures (PROMs) of a previous trial that showed that RO THA was associated with improved accuracy and reduced outliers in acetabular component positioning compared with CO THA. METHODS: This prospective cohort study included 50 patients undergoing CO THA versus 50 patients receiving RO THA. The Oxford hip score, Forgotten Joint Score (FJS), University of California at Los Angeles hip score were recorded at a minimum of 3 years following surgery. RESULTS: At minimum 3 years follow-up, there was no statistically significant difference in CO THA versus RO THA with respect to the Oxford hip score [median 42(6.25) versus 41(5.5), P = .914]; FJS [89 (9.25) versus 86 (9), P = .065], and University of California at Los Angeles score [median 7.5 (3) versus 7 (2), P = .381]. None of the study patients had dislocations or underwent revision surgery within 3 years follow-up. CONCLUSION: The previously reported improvement in accuracy of acetabular component in this study population did not translate to statistically significant improvements in PROMs. Patients in both groups achieved excellent PROMs and there was a trend towards higher FJS scores postoperatively in the RO THA group that did not reach statistical significance. Further studies are needed to assess the significance of these findings on longer-term clinical outcomes and implant survivorships, and also to explore the impact of the enhanced RO THA workflow and functional implant positioning on these outcomes.

Functional Component Positioning in Total Hip Arthroplasty and the Role of Robotic-Arm Assistance in Addressing Spinopelvic Pathology.

Hip, spine, and pelvis function as a unified kinetic chain. Any spinal pathology, results in compensatory changes in the other components to accommodate for the reduced spinopelvic motion. The complex relationship between spinopelvic mobility and component positioning in total hip arthroplasty presents a challenge in achieving functional implant positioning. Patients with spinal pathology, especially those with stiff spines and little change in sacral slope, are at high instability risk. In this challenging subgroup, robotic-arm assistance enables the execution of a patient specific plan, avoiding impingement and maximizing range of motion; especially utilizing virtual range of motion to dynamically assess impingement.

Functional implant positioning in total hip arthroplasty and the role of robotic-arm assistance.

INTRODUCTION: Accurate implant positioning, tailored to the phenotype and unique biomechanics of each patient is the single most important objective in achieving stability in THA and maximise range of motion. The spine-pelvis-hip construct functions as a single unit adapting to postural changes. It is widely accepted in the literature that no universaltarget exists and variations in spinopelvic mobility mandate adjustments to the surgical plan; thus bringing to the fore the concept of personalised, functional component positioning. METHODS: This manuscript aims to outline the challenges posed by spinopelvic imbalance and present a reproducible, stepwise approach to achieve functional-component positioning. We also present the one-year functional outcomes and Patient Reported Outcome Measures of a prospective cohort operated with this technique. RESULTS AND CONCLUSION: Robotic-arm assisted Total Hip Arthroplasty has facilitated enhanced planning based on the patient's phenotype and evidence suggests it results in more reproducible and accurate implant positioning. Preservation of offset, avoiding leg-length discrepancy, accurate restoration of the centre of rotation and accomplishing the combinedversion target are very important parameters in Total Hip Arthroplasty that affect post-operative implant longevity, patient satisfaction and clinical outcomes.