Enhancing robotic precision in medial UKA: Image-based robot-assisted system had higher accuracy in implant positioning than imageless robot-assisted system across 292 knees.

PURPOSE: The objective of this study was to compare the degree of accuracy in implant positioning and limb alignment offered by two robot-assisted (RA) systems: an image-based robot-assisted (IBRA) versus an imageless robot-assisted (ILRA) system for the treatment of medial knee osteoarthritis with unicompartmental knee arthroplasty (UKA). METHODS: This retrospective radiographic study included medial UKAs performed between 2011 and 2023. Radiographic measurements taken preoperatively and at 1-year postoperative control visit focusing on hip-knee-ankle angle (HKA), posterior tibial slope (PTS), tibial component coronal alignment relative to Cartier's angle and restoration of proper joint line (JL) height were analyzed. Outliers for postoperative measurements were defined as follows: HKA <175° or >180°, PTS <2° or >8°, >3° or <-3° alterations in Cartier's angle and ±2 mm changes in the height of the joint line. RESULTS: The final sample consisted of 292 medial UKAs: 95 (32.5%) with an IBRA system and 197 (67.5%) with an ILRA system. Implant positioning and limb alignment were more accurate in the group of patients treated with IBRA, HKA (77.9% vs. 67.5%, p = 0.07), PTS (93.7% vs. 82.7%, p = 0.01), restoration of tibial varus relative to Cartier's angle (87.4% vs. 65%, p < 0.001) and restoration of JL height (81.1% vs. 69.5%, p = 0.04). CONCLUSION: Medial UKA surgery using an IBRA system was associated with a higher degree of accuracy in implant positioning and postoperative limb alignment as compared to an ILRA system. This is a valuable contribution to help communicate the advantages of using this surgical technique and improve its reproducibility. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

Long-term functional success and robust implant survival in lateral unicompartmental knee arthroplasty: A case series with a mean follow-up of twenty two and a half years.

PURPOSE: Lateral unicompartmental knee arthroplasty (UKA) is an accepted treatment option in cases of end-stage lateral osteoarthritis. While lateral UKA has many proposed advantages compared to total knee arthroplasty, its technical challenges and relatively small number of cases make this an uncommon procedure. The aim of this study was to report the survivorship and functional outcomes beyond 20 years of follow-up of isolated UKA. METHODS: Between January 1988 and October 2003, 54 lateral UKAs were performed in a single center. The fitted prosthesis was a fixed plate and cemented polyethylene (PE). All patients had isolated lateral tibiofemoral osteoarthritis, including five open meniscectomies, three arthroscopies, and three open reductions of lateral tibial plateau fractures. Patients with a minimum of 20 years of follow-up were included in the final analysis. RESULTS: Of the 54 UKA, 22 died before reaching the minimum follow-up period and four were lost to follow-up. Twenty-eight were included in the final analysis. Among them, 21 patients remained alive and an additional seven were deceased after 20 years. The mean age at the last follow-up was 84.8 ± 11.9 years with a mean follow-up duration of 22.5 ± 2.1 years. Of the 28 knees, eight underwent revision surgery (5 for the progression of osteoarthritis; 2 for aseptic loosening; 1 for PE wear). Kaplan-Meier survival analysis revealed a survival rate at 20 and 25 years of 72.3% (CI 59.1; 88.6). The average time to revision was 14.9 ± 4.9 years. At the last follow-up, the mean function Knee Society Score (KSS) was 41.5 ± 32.9 and the mean objective KSS score was 79.4 ± 9.7. In the unrevised population, 94.7% of patients (n = 18) reported being satisfied or very satisfied with the surgery. CONCLUSION: Lateral UKA remains a viable treatment option for patients with isolated lateral tibiofemoral osteoarthritis, providing satisfactory 20-year implant survivorship and high patient satisfaction.

Nonanatomical femoral tunnel positioning in isolated MPFL reconstruction is not associated with an increased risk of patellofemoral osteoarthritis after a minimum follow-up of 10 years.

PURPOSE: The association between the prevalence of patellofemoral arthritis (PFA) and femoral tunnel positioning following isolated medial patellofemoral ligament reconstruction (MPFLr) has not been well described. The aim of this study was to analyse the relationship between femoral tunnel positioning and the prevalence of PFA. METHODS: This was a single-centre study of patients undergoing an isolated MPFLr between 2006 and 2011 with a minimum of 10 years of follow-up. Outcomes assessed were the presence of PFA on radiographs, recurrence of instability requiring revision surgery and patient-reported outcomes, including Kujala, Tegner and IKDC scores. Tunnel positioning was assessed on postoperative radiographs using two radiographic methods: Schöttle's point and the grid method to localise the femoral tunnel. Patients were grouped based on tunnel positioning and compared. RESULTS: Fifty patients were analysed at a mean follow-up of 12.4 years. Thirty-three patients (66%) had a femoral tunnel position within 7 mm of Schöttle's point and 39 (78%) within the anatomic quadrant, with the most common location according to the grid method in D4 (28%) and E4 (26%), respectively. Thirty-seven patients (74%) had a satisfactory (>80 versus <80) Kujala score at long-term follow-up. None of the examined tunnel assessment methods demonstrated a significant relationship with Tegner, Kujala or International Knee Documentation Committee scores. Patients with a femoral tunnel position >7 mm outside Schöttle's point or were considered to be in a nonanatomic position were not significantly more likely to result in unsatisfactory Kujala scores at the last follow-up. Tunnel positioning and the other tested parameters were not found to be significantly associated with the development of PFA. CONCLUSION: No correlation between femoral tunnel position and risk of PFA or poor outcomes was observed in patients undergoing isolated MPFLr at long-term follow-up. The impact of femoral tunnel placement on long-term outcomes in patients with PFI may be less significant than originally considered. LEVEL OF EVIDENCE: Level IV.

Surgical factors play a critical role in predicting functional outcomes using machine learning in robotic-assisted total knee arthroplasty.

PURPOSE: Predictive models help determine predictive factors necessary to improve functional outcomes after total knee arthroplasty (TKA). However, no study has assessed predictive models for functional outcomes after TKA based on the new concepts of personalised surgery and new technologies. This study aimed to develop and evaluate predictive modelling approaches to predict the achievement of minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) 1 year after TKA. METHODS: Four hundred thirty robotic-assisted TKAs were analysed in this retrospective study. The mean age was 67.9 ± 7.9 years; the mean body mass index (BMI) was 32.0 ± 6.8 kg/m2. The following PROMs were collected preoperatively and 1-year postoperatively: knee injury and osteoarthritis outcome score for joint replacement, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) Function, WOMAC Pain. Demographic data, preoperative CT scan, implant size, implant position on the robotic system and characteristics of the joint replacement procedure were selected as predictive variables. Four machine learning algorithms were trained to predict the MCID status at 1-year post-TKA for each PROM survey. 'No MCID' was chosen as the target. Models were evaluated by class discrimination (F1-score) and area under the receiver operating characteristic curve (ROC-AUC). RESULTS: The best-performing model was ridge logistic regression for WOMAC Function (area under the curve [AUC] = 0.80, F1 = 0.48, sensitivity = 0.79, specificity = 0.62). Variables most strongly contributing to not achieving MCID status were preoperative PROMs, high BMI and femoral resection depth (posterior and distal), supporting functional positioning principles. Conversely, variables contributing to a positive outcome (achieving MCID) were medial/lateral alignment of the tibial component, whether the procedure was an outpatient surgery and whether the patient received managed Medicare insurance. CONCLUSION: The most predictive variables included preoperative PROMs, BMI and surgical planning. The surgical predictive variables were valgus femoral alignment and femoral rotation, reflecting the benefits of personalised surgery. Including surgical variables in predictive models for functional outcomes after TKA should guide clinical and surgical decision-making for every patient. LEVEL OF EVIDENCE: Level III.

Enhancing soft tissue balance: Evaluating robotic-assisted functional positioning in varus knees across flexion and extension with quantitative sensor-guided technology.

PURPOSE: Functional implant positioning (FIP) for total knee arthroplasty (TKA) is an evolution of kinematic alignment based on preoperative CT scan and robotic-assisted technology. This study aimed to assess the ligament balancing of image-based robotic-assisted TKA in extension, mid-flexion and flexion with an FIP using intraoperative sensor-guided technology. The hypothesis was that image-based robotic-assisted TKA performed by FIP would achieve ligament balancing all along the arc of knee flexion. METHODS: This prospective monocentric study included 47 consecutive patients with varus knees undergoing image-based robotic-assisted TKA performed with FIP. After robotic-assisted bone cuts, trial components were inserted, and soft tissue balance was assessed using sensor-guided technology at 10°, 45° and 90° of knee flexion. A mediolateral balanced knee was defined by an intercompartmental pressure difference (ICPD) ≤ 15 lbf and medial and lateral compartment pressure ≤60 lbf. The mean age was 71.6 years old ±6.7, the mean BMI was 29.0 kg/m2 ± 4.9 and the mean preoperative HKA was 174° ± 5 [159; 183]. RESULTS: The mean postoperative knee alignment was 177.0° ± 2.2° [172; 181]. There were 93.6% of balanced knees (n = 44) at 10 and 90° of knee flexion versus 76.6% (n = 36) at 45° of knee flexion with a significant difference (p = 0.014). Median ICPD at 10, 45 and 90° of knee flexion were, respectively, 7.0 (interquartile range [IQR]: 9), 11.0 (IQR: 9.5) and 8.0 (IQR: 9.0). Pairwise analyses revealed differences for ICPD at 45° versus ICPD at 10° (p = 0.003) and ICPD at 90° versus ICPD at 45° (p = 0.007). CONCLUSION: FIP with an image-based robotic-assisted system allowed the restoration of a well-balanced knee at 10° and 90° of flexion in varus knees. Nevertheless, some discrepancies occurred in midflexion, and more work is needed to understand ligament behaviour all along the arc of knee flexion. LEVEL OF EVIDENCE: Level II.

Optimized decision algorithm for the microbiological diagnosis of osteoarticular infections in adults using synovial fluid samples: a prospective study in two French hospitals including 423 samples of synovial fluid.

No consensus exists about the techniques to use for microbiological diagnosis of bone and joint infections (BJIs). The objective herein was to define an algorithm to optimize BJI diagnosis in adults using various bacteriological methods on synovial fluid samples. This prospective multi-center study included 423 synovial fluids collected from adult patients with suspected BJIs. Culture (using five solid media, an enrichment broth, and blood culture bottles), universal 16S rRNA PCR followed by Sanger sequencing, and seven specific bacterial PCRs were systematically performed. Combinations of methods were compared to arrive at the optimized algorithm. Among 423 synovial fluids, 242 infections were diagnosed (57.2 %): 213 mono- and 29 poly-microbial for a total of 284 bacteria (staphylococci at 54.6 %, streptococci-enterococci at 16.5 %, Gram-negative bacilli at 15.5 %, anaerobic species at 8.8 %). Comparing culture techniques, blood culture bottles had the highest sensitivity (67.6 % for pediatric and 63.9 % for anaerobic bottles) but are not sufficient alone and require being combined with solid media. The 16S rDNA PCR detected only 52.3 % of the bacteria, whereas specific PCRs had a higher sensitivity (Staphylococcus spp. at 66.2 %, S. aureus at 85.2 %, Streptococcus spp. at 91.2 %). Based on these results, an algorithm was proposed associating three solid media; inoculation into blood culture bottles; and 16S, Staphylococcus spp., and Streptococcus spp. PCRs, which would have detected 90.5 % of bacteria in the present cohort versus 79.2 % using all culture techniques on synovial fluid. This prospective study shows that a combination of culture and molecular methods on synovial fluids allows the optimization of bacterial detection.

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.

Role of the Gut Microbiota in Osteoarthritis, Rheumatoid Arthritis, and Spondylarthritis: An Update on the Gut-Joint Axis.

Dysregulation of the gut microbiota and their metabolites is involved in the pathogenic process of intestinal diseases, and several pieces of evidence within the current literature have also highlighted a possible connection between the gut microbiota and the unfolding of inflammatory pathologies of the joints. This dysregulation is defined as the "gut-joint axis" and is based on the joint-gut interaction. It is widely recognized that the microbiota of the gut produce a variety of compounds, including enzymes, short-chain fatty acids, and metabolites. As a consequence, these proinflammatory compounds that bacteria produce, such as that of lipopolysaccharide, move from the "leaky gut" to the bloodstream, thereby leading to systemic inflammation which then reaches the joints, with consequences such as osteoarthritis, rheumatoid arthritis, and spondylarthritis. In this state-of-the-art research, the authors describe the connections between gut dysbiosis and osteoarthritis, rheumatoid arthritis, and spondylarthritis. Moreover, the diagnostic tools, outcome measures, and treatment options are elucidated. There is accumulating proof suggesting that the microbiota of the gut play an important part not only in immune-mediated, metabolic, and neurological illnesses but also in inflammatory joints. According to the authors, future studies should concentrate on developing innovative microbiota-targeted treatments and their effects on joint pathology as well as on organizing screening protocols to predict the onset of inflammatory joint disease based on gut dysbiosis.

[Evolving indications for partial knee replacement : New aspects]. / Update Indikation Teilprothese : Neue Aspekte.

BACKGROUND: Partial knee replacement has proven to be an effective therapy for advanced unicompartmental arthrosis of the knee. Despite continuous advancements in implants and surgical techniques over the past decades, the global preference for total knee arthroplasty still persists for historical reasons. OBJECTIVES: This report aims to illuminate advantages and disadvantages of partial knee replacement considering long-term results, the evolution of indication criteria over recent decades and new aspects in patient selection with potential improvements through emerging technologies. MATERIAL AND METHODS: The analysis involves the examination of long-term results from clinical studies and registry data, highlighting the risk factors for potential failures and their influence on the development of indication criteria. RESULTS: Present-day long-term results demonstrate excellent prosthetic survival, aligning with outcomes from total knee arthroplasty. New perspectives for expanding indication criteria are discussed, including the possible application of partial knee replacement in cases of severe varus deformity > 15°, anterior cruciate ligament insufficiency, young active patients, anterior knee pain, and/or patellofemoral arthritis, as well as mild radiographic arthritis with degenerative medial meniscus root tear and meniscal extrusion. DISCUSSION: Indication criteria have consistently expanded in recent years, taking into account modern insights, and the application of advanced technologies can enhance precision and minimize surgical errors. Furthermore, this report emphasizes that revision rates are not the sole criterion for success and underscores the necessity for a comprehensive examination of clinical results.

Management of fixed flexion contracture in primary total knee arthroplasty: recent systematic review.

INTRODUCTION: This study aimed to systematically review the literature and identify the surgical management strategy for fixed flexion contracture in primary total knee arthroplasty (TKA) surgery, pre-, intra-, and post-operatively. Secondary endpoints were etiologies and factors favoring flexion contracture. MATERIALS AND METHODS: Searches were carried out in November 2023 in several databases (Pubmed, Scopus, Cochrane, and Google Scholar) using the following keywords: "flexion contracture AND TKA", "fixed flexion deformity AND TKA", "posterior capsular release AND TKA", "posterior capsulotomy in TKA", "distal femoral resection AND TKA". Study quality was assessed using the STROBE checklist and the Downs and Black score. Data concerning factors or strategies leading to the development or prevention of flexion contracture after TKA were extracted from the text, figures, and tables of the included references. The effect of each predictive factor on flexion contracture after TKA was recorded. RESULTS: Thirty-one studies were identified to meet the inclusion and exclusion criteria. These studies described a variety of preoperative and intraoperative factors that contribute to the development or correction of postoperative flexion contracture. The only clearly identified predictor of postoperative flexion contracture was preoperative flexion contracture. Intraoperative steps described to correct flexion contracture were: soft-tissue balancing (in posterior and medial compartments), distal femoral resection, flexion of the femoral component, and posterior condylar resection. However, no study has investigated these factors in a global model. DISCUSSION: This review identified various pre-, intra-, and post-operative factors predictive of post-operative flexion contracture. In practice, these factors are likely to interact, and it is therefore crucial to further investigate them in a comprehensive model to develop an algorithm for the management of flexion contracture. LEVEL OF EVIDENCE: IV.

Risk of suprascapular nerve injury in open Trillat procedure: an anatomical study.

PURPOSE: The open Trillat Procedure described to treat recurrent shoulder instability, has a renewed interest with the advent of arthroscopy. The suprascapular nerve (SSN) is theoretically at risk during the drilling of the scapula near the spinoglenoid notch. The purpose of this study was to assess the relationship between the screw securing the coracoid transfer and the SSN during open Trillat Procedure and define a safe zone for the SSN. METHODS: In this anatomical study, an open Trillat Procedure was performed on ten shoulders specimens. The coracoid was fixed by a screw after partial osteotomy and antero-posterior drilling of the scapular neck. The SSN was dissected with identification of the screw. We measured the distances SSN-screw (distance 1) and SSN-glenoid rim (distance 2). In axial plane, we measured the angles between the glenoid plane and the screw (α angle) and between the glenoid plane and the SSN (ß angle). RESULTS: The mean distance SSN-screw was 8.8 mm +/-5.4 (0-15). Mean α angle was 11°+/-2.4 (8-15). Mean ß angle was 22°+/-6.7 (12-30). No macroscopic lesion of the SSN was recorded but in 20% (2 cases), the screw was in contact with the nerve. In both cases, the ß angle was measured at 12°. CONCLUSION: During the open Trillat Procedure, the SSN can be injured due to its anatomical location. Placement of the screw should be within 10° of the glenoid plane to minimize the risk of SSN injury and could require the use of a specific guide or arthroscopic-assisted surgery.

Influence of hamstring stiffness on anterior tibial translation after anterior cruciate ligament rupture.

BACKGROUND: There is a correlation between the hamstring stiffness and the decrease of anterior tibial translation in athletic patients with healthy knees. This observation could question the clinical reliability of the Lachman-Trillat test to detect complete ACL ruptures in patients with an important hamstring stiffness. This study aims to determine if anterior tibial translation is correlated with hamstring stiffness in patients with complete ACL rupture. METHODS: This is a prospective study including patients with unilateral complete ACL rupture confirmed by MRI. The arthrometer GNRB® was used to measure anterior tibial translation on both knees at 134 N and compute the side-to-side difference. The hamstring stiffness was assessed with the eccentric peak torque using the isokinetic dynamometer CON-TREX. Linear regressions were done between these two parameters on two study groups: one included all patients (GR1), and the other included only isolated ACL injuries without associated lesions (GR2). RESULTS: Fifty-two patients were included (29 men, 23 women) with an average of 34.9 years old. The mean eccentric peak torque of the hamstrings for pathological knees was 94.9Nm for GR1 and 91.7Nm for GR2. The mean side-to-side difference was 2.42 mm for GR1 and 1.99 mm for GR2. No significant correlations were identified for GR1 (p = 0.66) and GR2 (p = 0.105). CONCLUSION: No significant linear correlation was found between side-to-side difference measured by GNRB® and hamstring stiffness for pathological knees with complete ACL rupture. These results lead to believe that the Lachman-Trillat clinical test is not influenced by hamstring stiffness. LEVEL OF EVIDENCE: Prospective study, level of evidence IV.

What is the best fixation method in medial patellofemoral ligament reconstruction? A biomechanical comparison of common methods for femoral graft attachment.

INTRODUCTION: A variety of techniques have been described for femoral fixation in medial patellofemoral ligament reconstruction (MPFLr). The aim of this study was to compare the biomechanical performance of the most used methods for graft fixation in the femur using human cadaveric tissue. We wondered what is the best fixation method for femoral fixation in MPFL reconstruction? HYPOTHESIS: A suspensory fixation device provides the best femoral fixation. MATERIAL AND METHOD: Twenty cadaveric knees were tested. Four femoral fixation methods were compared (5 knees per group): interference fixation with a Biosure© RG 5 mm and a 7 mm, suture anchor (Healicoil Regenesorb 4.75 mm ©) and suspensory fixation with the Ultrabutton©. The testing was divided in preconditioning, cyclic loading and load to failure. Load to failure, elongation, stiffness and mode of failure were recorded and compared. RESULTS: The Ultrabutton© had the highest mean ultimate load (427 ± 215 N (p = 0.5)), followed by Healicoil anchor © (308 ± 44 N (p > 0.05)) and the interference screw of 7 mm (255 ± 170 N (p > 0.05)). Mean stiffness was similar in the Ultrabutton© and 4.75 mm. Healicoil anchor © groups (111 ± 21 N/mm and 119 ± 20 N/mm respectively), and lowest in 7 mm Biosure© screw fixation group (90 ± 5 N/mm). The Biosure© 5 mm RG screw presented 100% of premature rupture because of tendon slippage. The Ultrabutton© presented the lowest premature rupture (40%). DISCUSSION: A suspensory fixation for the femur had the lowest number of graft failures and highest load to failure. This study has implications for surgeons' choice of graft fixation in MPFLr. It is the first study to test the most commonly femoral used fixation methods, allowing direct comparisons between each method.

Collared versus collarless hydroxyapatite-coated stems for primary cementless total hip arthroplasty; a systematic review of comparative studies. Is there any difference in survival, functional, and radiographic outcomes?

INTRODUCTION: This systematic review aims to critically assess the literature comparative studies investigating collared and collarless Corail stem in primary total hip arthroplasty (THA) to find differences in revision rates, radiographic and clinical outcomes, and postoperative complications between these two types of the same stem. METHODS: Eligible studies were found by searching PubMed, Science Direct/Scopus, and the Cochrane Database of Systematic Reviews from conception till May 2023. The PRISMA guidelines were followed. The investigation encompassed randomized controlled trials, case series, comparative, cohort, and observational studies that assessed at least one comparative outcome or complication between collared and collarless Corail stems. RESULTS: Twelve comparative studies with 90,626 patients undergoing primary THA were included. There were 40,441 collared and 58,543 collarless stems. The follow-up ranged from 12 to 360 months. Our study demonstrated no significant difference in stem revision relative risk (RR = 0.68; 95% confidence interval (CI), 0.23, 2.02; p = 0.49), number of radiolucent lines (RR = 0.3; 95% CI, 0.06, 2.28; p = 0.29) and overall complication risk (RR = 0.62; 95% CI, 0.22, 1.76; p = 0.37) between collared and collarless stems. The collared stems demonstrated significantly lesser subsidence (mean difference: 1.01 mm; 95% CI, -1.77, -0.25; p = 0.009) and risk of periprosthetic fractures (RR = 0.52; 95% CI, 0.29, 0.92; p = 0.03). CONCLUSION: The comparative studies between collared and collarless stem groups showed similar survival and overall complication rates and functional outcomes. The similar revision rates between groups make the impact of higher subsidence for collarless stems uncertain. The lower risk of periprosthetic fractures in the collared stems group must be clarified further but could be related to increased rotational stability.

Monobloc dual-mobility acetabular component versus a standard single-mobility acetabular component.

Aims: The benefit of a dual-mobility acetabular component (DMC) for primary total hip arthroplasties (THAs) is controversial. This study aimed to compare the dislocation and complication rates when using a DMC compared to single-mobility (SM) acetabular component in primary elective THA using data collected at a single centre, and compare the revision rates and survival outcomes in these two groups. Methods: Between 2010 and 2019, 2,075 primary THAs using either a cementless DM or SM acetabular component were included. Indications for DMC were patients aged older than 70 years or with high risk of dislocation. All other patients received a SM acetabular component. Exclusion criteria were cemented implants, patients treated for femoral neck fracture, and follow-up of less than one year. In total, 1,940 THAs were analyzed: 1,149 DMC (59.2%) and 791 SM (40.8%). The mean age was 73 years (SD 9.2) in the DMC group and 57 years (SD 12) in the SM group. Complications and revisions have been analyzed retrospectively. Results: The mean follow-up was 41.9 months (SD 14; 12 to 134). There were significantly fewer dislocations in the DMC group (n = 2; 0.17%) compared to the SM group (n = 8; 1%) (p = 0.019). The femoral head size did not influence the dislocation rate in the SM group (p = 0.702). The overall complication rate in the DMC group was 5.1% (n = 59) and in the SM group was 6.7% (n = 53); these were not statistically different (p = 0.214). No specific complications were attributed to the use of DMCs. In the DMC group, 18 THAs (1.6%) were revised versus 15 THAs in the SM group (1.9%) (p = 0.709). There was no statistical difference for any cause of revisions in both groups. The acetabular component aseptic revision-free survival rates at five years were 98% in the DMC group and 97.3% in the SM group (p = 0.780). Conclusion: The use of a monobloc DMC had a lower risk of dislocation in a high-risk population than SM component in a low-risk population at the mid-term follow-up. There was no significant risk of component-specific complications or revisions with DMCs in this large cohort.