Search Results (10)

Background: This propensity-score-matched retrospective study compared radiographic accuracy and short-term functional outcomes between MAKO robotic-arm-assisted and conventional dual-incision minimally invasive total hip arthroplasty (THA). It was hypothesized that robotic assistance would provide superior radiographic accuracy, primarily smaller absolute deviations from the planned acetabular inclination and anteversion and a higher proportion of cups within the Lewinnek safe zone, without improving early functional outcomes. Methods: Consecutive patients who underwent dual-incision total hip arthroplasty were retrospectively analyzed at two affiliated institutions between March 2023 and March 2025. The study included 52 robotic-arm-assisted cases. The dual-incision technique used an anterolateral incision for acetabular preparation and cup implantation and a posterolateral incision for femoral preparation and stem implantation. Propensity score matching (1:1) generated 52 balanced pairs for age, sex, body mass index (BMI), preoperative Harris Hip Score (HHS), ASA class, and diagnosis. Operative time, blood loss, radiographic accuracy (acetabular anteversion, inclination, leg-length discrepancy [LLD], femoral and combined offsets, and stem subsidence), and functional outcomes (HHS, Oxford Hip Score [OHS], Forgotten Joint Score-12 [FJS-12]) were compared. Results: The robotic group achieved smaller deviations from the planned anteversion (1.15° vs. 3.0°, p < 0.001) and inclination (1.33° vs. 4.5°, p < 0.001), with a higher proportion of cups within the Lewinnek safe zone (98.1% vs. 82.7%, p = 0.016). Significant improvements were also seen in femoral stem subsidence (p = 0.006) and offset restoration, although the reduction in leg-length discrepancy did not reach statistical significance. Operative time was longer (77.8 vs. 65.0 min, p = 0.001), while blood loss and 6-month functional scores were comparable (HHS, p = 0.144; OHS, p = 0.328). Multivariable regression confirmed that greater deviations in acetabular orientation, higher LLD, and increased subsidence were independent predictors of poorer functional outcomes. Conclusions: MAKO robotic-arm assistance was associated with improved radiographic accuracy and biomechanical restoration in dual-incision THA, but no direct short-term functional advantage was observed. Greater radiographic precision was independently associated with better patient-reported outcomes, suggesting that technical precision is a key factor in optimizing early postoperative outcomes, highlighting the importance of technical accuracy in total hip arthroplasty. Full article

Background: Emerging parameters, such as the spino-pelvic unit and the combined sagittal index (CSI), are gaining importance in evaluating and optimizing implant positioning in total hip arthroplasty (THA). Our institution adopts the “femur first” technique to achieve the desired combined anteversion (CA). The purpose of this study is to evaluate the role of the ‘femur first’ technique and spinopelvic characteristics in achieving the CSI_standing ‘safe zone’ in primary THA. Methods: Consecutive patients undergoing primary THA were included in the present retrospective study. All patients underwent radiographic assessments in the standing position with the EOS 2D/3D radiography system. Results: Forty patients (40 hips) were enrolled. Of these, 34 patients fell inside the CSI_standing “safe zone” (205–245°). When considering the restricted CSI_standing “safe zone” for patients at high risk for adverse spinopelvic characteristics (215–245°), only 16 patients fell inside the range. We demonstrated a positive linear correlation between CSI_standing and CA (p < 0.0001). Pelvic tilt (PT) showed a positive correlation both in standing and relaxed sitting positions, (p < 0.001). Sacral slope (SS) showed a significant positive correlation in the relaxed sitting (p = 0.003) position but not in the standing position (p = 0.34). The correlation analysis between CSI_{relaxed-sitting} and ΔSS showed a positive correlation (p = 0.003). Conclusions: The “femur first” technique is able to achieve the CSI “safe zone” in most patients; however, it seems insufficient in those with adverse spinopelvic characteristics, who are at higher risk of dislocation. Moreover, the CA, the position of the pelvis in space (PT), and its mobility (ΔSS) greatly influence the CSI “safe zone” in patients undergoing primary THA. Full article

(1) Background: Imageless computer navigation systems have the potential to improve the accuracy of acetabular cup position in total hip arthroplasty (THA). Popular imageless navigation methods include locating the patient in a three-dimensional space (registration method) while using a baseline to angle the acetabular cup (reference plane). This study aims to compare the accuracy of different methods for determining postoperative acetabular cup positioning in THA via the direct anterior approach. (2) Methods: Fifty-one participants were recruited. Optical and inertial sensor imageless navigation systems were used simultaneously with three combinations of registration methods and reference planes: the anterior pelvic plane (APP), the anterior superior iliac spine (ASIS) and the table tilt (TT) method. Postoperative acetabular cup position, inclination, and anteversion were assessed using CT scans. (3) Results: For inclination, the mean absolute error (MAE) was lower using the TT method (2.4° ± 1.7°) compared to the ASIS (2.8° ± 1.7°, p = 0.17) and APP method (3.7° ± 2.1°, p < 0.001). For anteversion, the MAE was significantly lower for the TT method (2.4° ± 1.8°) in contrast to the ASIS (3.9° ± 3.2°, p = 0.005) and APP method (9.1° ± 6.2°, p < 0.001). (4) Conclusion: A functional reference plane is superior to an anatomic reference plane to accurately measure intraoperative acetabular cup inclination and anteversion in THA using inertial imageless navigation systems. Full article

Ischiofemoral impingement syndrome is a neglected cause of posterior hip pain which is derived from narrowing of the space between the lateral aspect of the ischium and the medial aspect of the lesser trochanter. Its diagnosis is challenging and requires the combination of physical tests and imaging studies. In the present narrative review, we found that femoral anteversion predisposes patients to the narrowing of the ischiofemoral space and subsequent quadratus femoris muscle injury. Magnetic resonance imaging serves as the gold-standard diagnostic tool, which facilities the quantification of the ischiofemoral distance and the recognition of edema/fat infiltration/tearing of the quadratus femoris muscle. Ultrasound is useful for scrutinizing the integrity of deep gluteal muscles, and its capability to measure the ischiofemoral space is comparable to that of magnetic resonance. Various injection regimens can be applied to treat ischiofemoral impingement syndrome under ultrasound guidance and they appear to be safe and effective. Finally, more randomized controlled trials are needed to build solid bases of evidence on ultrasound-guided interventions in the management of ischiofemoral impingement syndrome. Full article

Edge-wear in acetabular cups is known to be correlated with greater volumes of material loss; the location of this wear pattern in vivo is less understood. Statistical shape modelling (SSM) may provide further insight into this. This study aimed to identify the most common locations of wear in vivo, by combining CT imaging, retrieval analysis and SMM. Shape variance was described in 20 retrieved metal-on-metal acetabular surfaces. These were revised after a mean of 90 months, from 13 female and seven male patients. They were positioned with a mean inclination and anteversion of 53° and 30°, respectively. Their orientation, in vivo, was established using their stabilising fins, visible in pre-revision CT imaging. The impact of wear volume, positioning, time, gender and size on the in vivo location of wear was investigated. These surfaces had a mean wear volume of 49.63 mm³. The mean acetabular surface displayed superior edge-wear centred 7° within the posterosuperior quadrant, while more of the volumetric wear occurred in the anterosuperior quadrant. Components with higher inclination had greater superior edge-wear scars, while a relationship was observed between greater anteversion angles and more posterosuperior edge-wear. This SSM method can further our understanding of hip implant function, informing future design and may help to refine the safe zone for implant positioning. Full article

Reverse total shoulder arthroplasty presents itself sometimes as challenging when it comes to addressing massive bone loss, either in primary or revision settings. Custom components recently have made their way into shoulder prosthetics and are meant to help in the case of extensive glenoid bone destruction. Because of strict indication and the fairly recent introduction of these implants, the usage of custom-made glenoid implants is not very common yet. However, the early results are promising. The purpose of this review was to summarize and analyze the available literature. Therefore, a systematic review was performed according to PRISMA guidelines. A comprehensive search of the databases PubMed, Cochrane, and Livivo was performed to screen for studies reporting on clinical and radiological outcomes of custom glenoid implants. Four studies with a total of 46 shoulders were included in this review. The mean patient age was 68.8 years and the mean time of follow-up was 24.3 months. The weighted means showed an increase in CMS (32.7 points), in ASES (39.8 points), in anteversion (67.4 degrees), and in abduction (51.9 degrees) and a decrease in VAS (5.4 points). Custom-made glenoid implants are therefore a viable option in cases of large combined glenoid bone loss, both in primary and revision shoulder arthroplasty. Full article

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. Full article

Torsional deformities of the lower limb are common in children with cerebral palsy (CP)-determining gait problems. The mechanisms underlying transverse plane gait deviations arise from a combination of dynamic and static factors. The dynamic elements may be due to spasticity, contractures and muscle imbalances, while the static ones may result from excessive femoral anteversion, which decreases the efficiency of the hip abductors by reducing the muscular lever arms. A therapeutic approach has been identified in multi-level functional surgery for the lower limb. Treating the malalignments of the lower limb with femoral or tibial derotation provides optimal results, especially when supported by adequate biomechanical planning. This planning requires an integrated static-dynamic approach of morphological and functional evaluation, based on radiological measurements, physical examination and gait analysis. Instrumented gait analysis has been confirmed as essential in the evaluation and surgical decision making process for children affected by CP with transverse plane deformities. Computational simulations based on musculoskeletal models that integrate patient-specific CT morphological data into gait analysis can be used for the implementation of a surgical simulation system in pre-operative planning to test the possible effects of the different surgical treatment options on the torsional defects of the lower limbs. Recently, a computer-aided simulation process has been implemented in the preoperative planning of complex osteotomies for limb deformities in children. Three-dimensional (3D) digital models were generated from Computed Tomography (CT) scans, using free open-source software. The aim of this study is to integrate the patient-specific CT musculoskeletal model with morphological data and gait analysis data, with the personalized calculation of kinematic and kinetic parameters, which allow us to generate an “avatar” of the patient for a more in-depth evaluation of the gait abnormalities. The computational simulation platform proposed provides a realistic movable musculoskeletal model in a virtual environment, with the possibility of planning and monitoring the effects of virtual three-dimensional surgical corrections. Full article

“Safe zones” for cup position are currently being investigated in total hip arthroplasty (THA). This study aimed to evaluate the impact of bony impingement on the safe zone and provide recommendations for cup position in THA. CT scans were performed on 123 patients who underwent a cementless THA. Using the implant data and bone morphology from the CT scans, an impingement detection algorithm simulating range of motion (ROM) determined the presence of prosthetic and/or bony impingement. An impingement-free zone of motion was determined for each patient. These zones were then compared across all patients to establish an optimized impingement-free “safe zone”. Bony impingement reduced the impingement-free zone of motion in 49.6% (61/123) of patients. A mean reduction of 23.4% in safe zone size was observed in relation to periprosthetic impingement. The superposition of the safe zones showed the highest probability of impingement-free ROM with cup position angles within 40–50° of inclination and 20–30° of anteversion in relation to the applied cup and stem design of this study. Virtual ROM simulations identified bony impingement at the anterosuperior acetabular rim for internal rotation at 90° of flexion and at the posteroinferior rim for adduction as the main reasons for bony impingement. Full article

Background Relevant criteria for total hip arthroplasty (THA) planning have been introduced in the literature which include the hip range of motion, bony coverage, anterior cup overhang, leg length discrepancy, edge loading risk, and wear. The optimal implant design and alignment depends on the patient’s anatomy and patient-specific functional parameters such as the pelvic tilt. The approaches proposed in literature often consider one or more criteria for THA planning. but to the best of our knowledge none of them follow an integrated approach including all criteria for the definition of a patient-specific combined target zone (PSCTZ). Questions/purposes (1) How can we calculate suitable THA implant and implantation parameters for a specific patient considering all relevant criteria? (2) Are the resulting target zones in the range of conventional safe zones? (3) Do patients who fulfil these combined criteria have a better outcome score? Methods A method is presented that calculates individual target zones based on the morphology, range of motion and load acting on the hip joint and merges them into the PSCTZ. In a retrospective analysis of 198 THA patients, it was calculated whether the patients were inside or outside the Lewinnek safe zone, Dorr combined anteversion range and PSCTZ. The postoperative Harris Hip Scores (HHS) between insiders and outsiders were compared. Results 11 patients were inside the PSCTZ. Patients inside and outside the PSCTZ showed no significant difference in the HHS. However, a significant higher HHS was observed for the insiders of two of the three sub-target zones incorporated in the PSCTZ. By combining the sub-target zones in the PSCTZ, all PSCTZ insiders except one had an HHS higher than 90. Conclusions The results might suggest that, for a prosthesis implanted in the PSCTZ a low outcome score of the patient is less likely than using the conventional safe zones by Lewinnek and Dorr. For future studies, a larger cohort of patients inside the PSCTZ is needed which can only be achieved if the cases are planned prospectively with the method introduced in this paper. Clinical Relevance The method presented in this paper could help the surgeon combining multiple different criteria during THA planning and find the suitable implant design and alignment for a specific patient. Full article