To explore the clinical significance of the artificial intelligence (AI)-assisted three-dimensional (3D) planning system AI-HIP in total hip arthroplasty (THA) and evaluate its accuracy and efficacy in clinical practice. Preoperative planning was done using the AI-HIP system in the AI group and two-dimensional (2D) template measurements in the conventional group. The two groups were compared for postoperative radiographic results, perioperative monitoring indicators, and the degree of consistency between preoperative planning and actual implant size. Postoperative Harris scores, hip joint range of motion (ROM), and Barthel index were used to evaluate clinical effectiveness. None of the patients who ultimately completed the 6-months follow-up experienced adverse events such as hip dislocation and infection during follow-up. Compared to the conventional group, the AI group had significantly higher Harris scores (P = 0.026), hip ROM (P = 0.018), Barthel index (P = 0.042) at 6months postoperatively, and conformity rates of the acetabular (P = 0.001) and femoral components (P < 0.001) between intraoperative application of prosthesis model and preoperative planning. Additionally, the AI group had significantly shorter operation time (P = 0.041), less intraoperative blood loss (P = 0.012), and smaller discrepancy between bilateral acetabular offset (P = 0.032) and vertical distance of hip center of rotation (P = 0.011). However, no statistically significant intergroup differences were observed for the acetabular abduction angle, anteversion angle, femoral offset and leg length discrepancy. Preoperative planning for THA using the AI-HIP system has a high accuracy rate and allows for effective reconstruction of the rotation center and acetabular offset, reduction of surgical time, and early recovery of joint function. Further research is needed to confirm its potential clinical value. ChiCTR210004826, Date:28/03/2021, https://www.chictr.org.cn/showproj.html? proj=52846.

Precise acetabular cup positioning is critical for the success and longevity of total hip arthroplasty (THA). Robotic-assisted systems enhance placement accuracy, with closed-platform systems being well-established. A pertinent question is whether newer open-platform systems, which offer implant flexibility, achieve comparable accuracy. This study evaluates the radiographic accuracy of a novel, open-platform robotic system (Yuanhua KUNWU) in achieving the planned acetabular component position. A multi-centre retrospective review of 87 consecutive primary robotic THA procedures performed using the KUNWU system was conducted. Pre-operative CT-based planning defined the target acetabular inclination (AI) and anteversion (AV). The primary outcome was the deviation between the planned position and the post-operative CT-measured position. Secondary outcomes included the proportion of cups within the Lewinnek and Callanan safe zones and the accuracy of leg length and offset restoration. The mean deviation from the planned position to the post-operative CT was -2.7° for inclination (95% CI: -3.7° to -1.8°, P < 0.001) and 1.0° for anteversion (P = 0.058). Overall, 80.5% (70/87) of cups were placed within the combined Lewinnek and Callanan safe zones. A significant difference was found in combined offset (mean 2.79mm, P = 0.002) but not in leg length discrepancy (P = 0.302). Interobserver reliability was excellent for all measurements. The KUNWU open-platform robotic system facilitates accurate and reliable acetabular cup positioning, with minimal deviations from the pre-operative plan and a high rate of placement within the classic safe zones. These results support its use as a precise tool for component positioning in THA.

The functionality of the hip joint is primarily determined by the anatomical relationship between acetabulum and femur. Impairment of this relationship can lead to diseases such as femoroacetabular impingement and hip osteoarthritis. In patients undergoing total hip arthroplasty, accurate placement of the acetabular and femoral components in accordance with native 3-dimensional anatomy (3D) is crucial for obtaining prosthesis stability and survival, also for preventing postoperative complications such as wear, dislocation and osteolysis. Therefore, 3D determination of native anatomical features of the hip joint is highly important. A total of 100 adults were randomly selected. Right femur and acetabulum were segmented using MIMICS program. 2D and 3D measurements of femoral anteversion according to posterior condylar and transepicondylar axis, acetabular anteversion, acetabular inclination and combined anteversion were determined. The differences between gender groups and the correlations of two- and three-dimensional measurement results were evaluated. According to 2D and 3D measurements, statistically significant differences were observed between gender groups in all parameters except for 2D acetabular inclination. A very strong correlation was observed between 3D femoral anteversion measurements performed using the posterior condylar axis and transepicondylar axis. Our findings revealed statistically significant differences between 2D and 3D measurements in most parameters, which have clinical relevance. A very strong correlation between femoral anteversion measurements obtained using the transepicondylar and posterior condylar axes supports the intraoperative use of the transepicondylar axis reliably. We believe the data obtained from our study will contribute to understand the 3-dimensional native anatomy of the hip joint.

Revision total hip arthroplasty (THA) for isolated polyethylene exchange or acetabular revision with retention of the femoral component can present a challenge for adequate exposure. A systematic approach to a proper release can facilitate exposure and reduce the risk of iatrogenic complications. The posterior approach is an extensile and versatile approach for revision THA. After incising the fascia and iliotibial band, the insertion of the gluteus maximus is fully released. After releasing any scar along the inferior gluteus medius, a retractor is placed to hold the muscle belly cranially. The leg is gently internally rotated to place the posterior capsule and external rotators under tension while these structures are released from the posterior femur and along the neck of the femoral component. Curved scissors can be utilized to identify the psoas sheath and to release the inferior capsule while protecting the iliopsoas tendon. Scar tissue is resected from inside the hip joint, and a pocket is made in the anterior capsule to allow retractor placement above the equator of the acetabulum in order to hold the mobilized proximal femur anteriorly. An inferior retractor is then placed under the transverse acetabular ligament. This systematic approach allows adequate visualization of the acetabular component for revision. Nonoperative treatment should be attempted first, depending on the diagnosis and its associated natural history. Once nonoperative treatment has been exhausted and revision THA is indicated, the anterior and direct lateral approaches can be considered. If the femoral component needs revision on the basis of intraoperative assessment, the anterior approach presents substantial difficulty in femoral exposure, with a higher risk of iatrogenic fracture. The direct lateral approach commonly leads to abductor weakness and a Trendelenburg gait. Common indications for revision THA with femoral component retention include wear and/or osteolysis, adverse local tissue reaction, recurrent instability, and aseptic acetabular loosening. Adequate exposure is essential to facilitate revision THA with femoral component retention and to minimize the risk of iatrogenic injury. Survivorship free from re-revision at 2 years is >80% for both isolated polyethylene exchange and acetabular revision. There is a trend toward higher failure rates when retaining the acetabular component. Risk factors for failure include damage to the locking mechanism; femoral head erosion into the cup, damaging the metal; and a mispositioned acetabular component. A systematic approach to releases is essential for adequate exposure with a retained femoral component. Systematic releases include fully releasing the gluteus maximus insertion, continuing the iliotibial band incision distally, fully releasing the external rotators, and removing scar tissue within the joint.Keeping the hip extended and the knee flexed with a finger posteriorly is important to protect the sciatic nerve during the release of the posterior capsule. The hip can then be dislocated in a controlled manner to reduce the risk of iatrogenic injury.Be prepared for bleeding from perforating arteries during subvastus elevation.Rest the leg on a padded Mayo stand in slight internal rotation once the proximal femur is retracted anteriorly.Ensure proper component alignment, component stability, and hip stability to confirm that femoral component retention is indicated. Repair of the posterior capsule contributes substantially to postoperative stability.Precautions should be implemented postoperatively to reduce the risk of dislocation. A hip abduction brace can be considered for patients at a high risk of instability.Active ankle dorsiflexion should be assessed in the post-anesthesia unit to evaluate for sciatic nerve injury and to differentiate the cause of a foot drop if discovered on postoperative day 1. AP = anterior-posteriorCT = computerized tomographyCRP = c-reactive proteinESR = erythrocyte sedimentation rateFDA = Food & Drug AdministrationHR = Hazard ratioIT = Iliotibial bandMSIS = Musculoskeletal Infection SocietyOR = Odds ratioTHA = total hip arthroplastyrTHA = revision total hip arthroplasty.

Hybrid total hip arthroplasty in patients aged over 75: Patient-reported outcomes and complication rates.

There is conflicting data on the long-term survivorship following revision THA for instability. The aim of this study is to assess the survivorship of the first revision THA when undertaken for instability and identify patient and surgical factors associated with failure. Institutional Review Board approval was obtained for this retrospective cohort study from a tertiary referral centre in an academic hospital. There were 678 patients undergoing revision THA for instability during the period 01/01/2000 to 01/01/2022 identified from an institutional database. Of these cases, 290 (42.8%) were the index revision procedure (median age 65.9 years (inter-quartile range (IQR) 57–76); females 180 (62.1%); median body mass index (BMI) 28.1 (IQR 24.3–32.2)). The primary outcome of interest was re-revision surgery for instability. The mean time from surgery to the last follow-up date was 11.4 years (min 2 years to max 22 years). Re-revision was defined as addition or exchange of implants. Implant survivorship at 10 years, with censoring for death and loss to follow-up, was calculated using Kaplan-Meier estimates with 95% confidence intervals (CI). Multivariable Cox proportional hazard regression modelling was used to assess variables associated with 10-year survival and are reported as hazard ratios (HR) with 95% CI. The main patterns of hip instability were classified as malposition of the acetabular component (27.7%), impingement (36.7%) or late polyethylene wear (19.4%). The majority of revisions involved either modular exchange (liner + femoral head) (44.5%) or acetabular component revision with modular exchange (39.4%). At latest follow-up, there were 82 (28.3%) deaths, and 84 (29%) hips underwent at least one re-revision. The majority of failures (77.8%) occurred within 5 years of the initial revision surgery and the indications for re-revision were recurrent instability (66.7%), periprosthetic joint infection (13.3%), pseudotumour formation (8.9%), loosening and wear (6.7%) and periprosthetic fracture (4.4%). Ten-year Kaplan-Meier survivorship estimates were 80.0% (95%CI 73.4–87.3) for instability as the primary end-point (Figure 1) and 70.7% (95%CI 63.2–79.2) when considering all indications for re-revision THA. Modular component exchange alone was significantly associated with re-revision THA for instability compared to procedures which included revision of the femoral stem, acetabular component or both (HR 1.89 (95% CI 1.1–4.1), p = 0.02). Factors associated with increased re-revision risk within 10 years for any cause were younger age at surgery (HR 0.39 95%CI 0.19–0.75, p = 0.005) and using a constrained liner (HR 3.0 95%CI 1.3–7.3, p = 0.04). There is a high rate of recurrence within 10 years when the first revision THA is undertaken for hip instability. The risk of re-revision THA for instability was highest in patients undergoing modular component exchange alone. Use of a constrained liner was significantly associated with an increased all-cause re-revision risk within 10 years; however this may reflect unmeasured confounding as these implants are typically used in the highest risk patients. For any figures or tables, please contact the authors directly.

A novel reverse total hip arthroplasty (RTHA) design has been developed with enhanced mechanical stability at extremes of motion in all planes by reversing the articulating surfaces using a femoral cup and acetabular ball. The purpose of this study was to assess the implant-bone fixation using radiostereometric analysis, assess the linear wear of the cross-linked polyethylene insert and monitor the clinical safety and efficacy of this novel design as a hip arthroplasty device. Twenty two subjects with end-stage osteoarthritis of the hip were enrolled at a single center in this regulator-approved investigational device trial. All patients underwent a RTHA utilizing at least 1 acetabular screw for augmented fixation with the Reverse Hip Replacement System. RSA markers were inserted into the innominate bone and proximal femur prior to implant insertion. Model-Based RSA was used to assess migration between the implants and bone and the polyethylene linear wear with assessments at six weeks (baseline), six, 12, 24 and 60 months from surgery. Patient reported outcome metrics were collected pre-operatively and at each post-operative visit including Oxford Hip Score-12, Harris Hip Score (HHS), European Quailty of Life (EQ-5D), HOOS and SF-36. Analysis was performed using one-sided and paired t-tests. The cohort consisted of 11 females and 11 males with mean age of 70.8 years and body mass index 31.3 kg/m2. Mean femoral subsidence from baseline at 6, 12, 24 and 60 months was 0.01±0.12mm, −0.00±0.19mm, −0.00±0.19mm and −0.06±0.21mm, all below the published critical threshold of 1.5mm (p The femoral and acetabular components both appeared well fixed at 5 years as assessed with RSA suggesting a low-risk of long-term aseptic loosening. Polyethylene linear wear was approaching the detection limit for assessment and within accepted limits. The results indicate acceptable radiographic safety and clinical efficacy of this novel reverse total hip arthroplasty design.

Abstract Background Acetabular bone defects remain a challenging problem in revision total hip arthroplasty (THA). Structural allografts can restore the native hip center of rotation and replenish bone stock for potential future revisions, offering a cost-effective alternative in settings with limited access to porous metal augments. This study aimed to evaluate the short- to mid-term clinical and radiographic outcomes of acetabular revisions using structural homologous bone block grafts combined with cemented acetabular components. Methods We retrospectively reviewed 13 consecutive patients (13 hips) with Paprosky type 2B, 2C, 3A, or 3B acetabular defects who underwent revision THA between February 2016 and October 2021. All cases were reconstructed using a structural homologous bone block graft, fixed to the ilium with screws, and a cemented polyethylene acetabular cup. Harris Hip Score (HHS) and standardized radiographs were assessed at the last follow-up. Implant survival and graft origin were analyzed using Kaplan–Meier curves and the log-rank test. Results The mean patient age was 67.3 years (range, 44–85), and the mean follow-up was 54 months (range, 19–88). Two patients (15.4%) experienced reconstruction failure due to graft fragmentation and cup migration. The remaining 11 cases demonstrated satisfactory clinical and radiographic outcomes, with evidence of graft integration and no radiographic signs of loosening. Mean HHS improved from 34.5 ± 7.0 preoperatively to 70.1 ± 10.3 postoperatively. Conclusion Structural allograft with a cemented acetabular component provided good short- to mid-term functional outcomes and radiographic stability in most patients. This technique remains a valuable, lower-cost option for managing major acetabular defects in resource-limited settings. Level of evidence : IV, retrospective case series.

Background: The objective of this study was to evaluate the short-term clinical and radiological outcomes of a conservative cementless stem (Minima) in total hip arthroplasty (THA) for patients presenting with a narrow femoral canal. Methods: We retrospectively analyzed 18 patients (18 THAs) who received a size 1 Minima stem between 2018 and 2022. Clinical assessment was performed using the Harris Hip Score (HHS). Radiological evaluation focused on stem migration, trabecular bone development, cortical hypertrophy, and the presence of radiolucent or reactive lines. Implant survival was determined using Kaplan-Meier analysis. Results: The mean patient age was 51.6 years, with an average follow-up of 57 months. The mean HHS improved significantly from 38.3 preoperatively to 96.4 at the final evaluation (p < 0.001). Initial stem migration occurred in two hips (11.1%) within the first 6 postoperative months, with no further progression or loosening observed thereafter. Bony trabecular development was identified in Gruen zones 3 (27.8%), 4 (5.5%), and 5 (16.7%). Reactive lines were present around four stems (zones 3-5). One intraoperative complication (5.5%) occurred (acetabular component migration during trial reduction), which required screw fixation. No revisions were performed. Both clinical and radiological implant survival at the final follow-up was 100.0%. Conclusions: At a mean follow-up of 57 months, the use of the size 1 Minima stem in patients with a narrow femoral canal demonstrated excellent clinical and radiological outcomes. These findings suggest that this conservative stem is a reliable option for this specific patient population.

Purpose: Revision total hip arthroplasty (RTHA) in the presence of a well-fixed femoral stem is associated with increased risk, as stem removal often results in bone loss, prolonged operative time, and greater blood loss. This problem is particularly relevant for older implants with a 14/16 taper, which is incompatible with most modern femoral heads. The Bioball™ System, a modular head–neck adapter, allows for acetabular or head-only revision while preserving the femoral stem. This study aimed to evaluate long-term clinical and radiological outcomes of RTHA using the Bioball™ System in patients with 14/16 tapers. Methods: A total of 38 patients (23 women, 15 men; mean age 73.5 years) met the inclusion criteria. All procedures were carried out with a well-fixed femoral stem and a 14/16 taper. Revisions were limited to exchange of the acetabular component, liner, or both, avoiding stem removal. The primary indication was acetabular cup loosening (n = 29, 76.3%); liner-only exchange was performed in 9 patients (23.7%). Clinical outcomes were assessed using the modified Merle d’Aubigné and Postel (MAP) score, and radiological evaluation focused on fixation, migration, and loosening. Mean follow-up was 8.44 years. Results: Both the acetabular component and liner were replaced in 76.3% of patients, while 23.7% underwent liner and head exchange only. Longer adapter sizes were most frequently used, and a 7.5° offset adapter was applied in 57.9% of cases. The modified MAP score improved by a mean of 5.7 points (p < 0.05), and VAS pain scores decreased from 7.4 to 2.6 (p < 0.05). No radiological signs of loosening were observed at final follow-up. Conclusions: The Bioball™ System enables effective restoration of hip stability and offset without femoral stem removal, offering favorable long-term clinical and radiological outcomes in revisions involving older 14/16 tapers.

An acetabular component made from highly cross-linked polyethylene enriched with vitamin E: 10-year clinical results and wear rates.

Screw Placement Influence on Implant Stability and Osseointegration Potential in Revision Hip Arthroplasty Involving Acetabular Defects: A Cohort-Based Modeling Study.

When positioning the acetabular component for total hip arthroplasty (THA) in patients with sequelae of Legg-Calvé-Perthes disease (LCPD), elevating the center of rotation (COR) of the hip is often unavoidable. We aimed to compare the outcomes between the preserved and elevated COR groups in patients with sequelae of LCPD. We enrolled 53 patients who underwent primary THA for sequelae of LCPD between 2006 and 2019. Patients were divided into 2 groups based on the postoperative COR position: 19 in the preserved COR group and 34 in the elevated COR group. The mean elevation of COR was 2.7 mm (range, 0-5.0 mm) in the preserved COR group and 8.1 mm (range, 6.0-12.0 mm) in the elevated COR group. Radiological outcomes, such as osteolysis and implant loosening, were evaluated. Additionally, reoperation, perioperative complications, limping gait, pelvic obliquity, and the modified Harris hip score (mHHS) were assessed. There were no significant differences in radiological or clinical outcomes between the 2 groups. Neither osteolysis nor implant loosening was observed, and no reoperations were required. Intraoperative periprosthetic femoral fractures occurred in 3 cases (6%), but no cases of sciatic nerve palsy were observed. Residual limping gait was noted in 10 patients (19%), and pelvic obliquity persisted in 8 patients (15%). At the last follow-up, the mean mHHS was 89.2. The 5-17-year follow-up results of primary cementless THA in patients with sequelae of LCPD were satisfactory. Furthermore, a moderate elevation of the COR, with a mean of 8.1 mm (range, 6.0-12.0 mm), did not significantly affect the outcomes of THA in these patients. Therefore, a moderate elevation of the COR can be considered an acceptable option for patients undergoing THA with sequelae of LCPD.

BackgroundIn total hip arthroplasty (THA), implant position is one of the critical factors affecting implant longevity, clinical outcomes, and postoperative complications. Although a number of studies have reported the accuracy of acetabular component positioning using a computed tomography (CT)-based navigation system, the significance of femoral stem anteversion has not been well addressed in the literature.MethodsStem anteversion in 83 patients who underwent primary THA and bipolar hemiarthroplasty was simultaneously measured with both a CT-based navigation system and a mechanical alignment guide during surgery. Both intraoperative measurement values were compared with the postoperative measurement values using the same three-dimensional coordinate system.ResultsThe absolute discrepancy between the mechanical alignment guide value and the postoperative stem anteversion was 7.6° ± 5.2° (range: 0° to 17°). On the other hand, the absolute discrepancy between the intraoperative stem anteversion value measured with CT-based navigation and the postoperative stem anteversion was 2.9° ± 3.1° (range: 0° to 14°). The absolute discrepancy was significantly lower in intraoperative CT-based navigation (p = 0.001).ConclusionIntraoperative stem anteversion measurements using CT-based navigation were more accurate than those using the mechanical alignment guide.

Relevance. The consequences of acetabular fractures most often manifest as coxarthtrosis and/or aseptic necrosis of the femoral head. One of the most important issues is proper positioning of the artificial hip socket, which depends on anatomical conditions. Objective. This study aims to analyze the outcomes of total hip arthroplasty (THA) in patients with sequelae of acetabular fractures and to compare functional results depending on the complexity of acetabular component positioning. Material and Methods. Seventy patients aged 24–67 years with sequelae of acetabular fractures who underwent THA were divided into two groups: group I (31 cases), when the positioning of the acetabular component was not problematic; group II (39 cases), when the positioning of the acetabular component of the prosthesis was technically difficult. Functional outcomes were assessed in all patients 2–15 years after surgery using the Harris Hip Score (HHS). Results. Baseline HHS scores were significantly higher in group I compared with group II (55.7 ± 11.7 vs. 35.9 ± 10.4; p &lt; 0.001, two-sample t-test). Final THA outcomes were also significantly better in group I than in group II (94.3 ± 4.6 vs. 90.6 ± 8.7; p = 0.026, two-sample t-test). However, consideration of the minimal clinically important difference (MCID) for HHS indicated a clinically insignificant difference. Conclusions. Accurate restoration of anatomy, particularly the hip joint’s center of rotation, is a key success factor ensuring proper prosthesis function, stability, optimal muscle biomechanics, and implant longevity. An individualized and differentiated approach to THA in patients with sequelae of acetabular fractures allows for good and excellent anatomical and functional treatment outcomes, with the average HHS values exceeding 90 percent.

IntroductionThe utilization of total hip arthroplasty (THA) in skeletally immature patients remains controversial, with an open triradiate cartilage traditionally perceived as a relative contraindication due to concerns of acetabular fixation and component loosening. Early evidence suggests that THA may be a feasible option in this patient population yielding favorable short-term outcomes, however larger series and mid-term data are lacking. This study presents the largest series of THA in patients with open triradiate cartilage to date with mid-term clinical, radiographic, and patient-reported outcomes.MethodsA retrospective review of our institutional Total Joint Registry identified 19 patients (22 hips) who underwent THA while having an open triradiate cartilage growth plate between the year 2000 and 2024. Skeletal maturity was assessed utilizing the modified Oxford bone age and all patients had a score of “1” or “2” on the triradiate cartilage stage of maturation. Demographics, surgical characteristics, implant data, radiographic parameters, and clinical outcomes were collected. Functional hip scores were assessed via the Harris Hip Score (HHS). Kaplan-Meier analysis was performed to analyze reoperation rates.ResultsThe average age at surgery was 14 years (SD=1.68), the average BMI was 24 (SD=7.1) and 64% were male. Mean follow-up was 6.05 years (range 1-15). The mean modified Oxford bone age for this cohort was 23 (SD=1.4). The most common indications for THA were avascular necrosis (64%), degenerative joint disease (27%), and neoplasia (9%). Preoperatively, 54.5% of patients utilized gait aids. Postoperatively, all patients reported independent ambulation without assistive devices with an average HHS of 91.65 (SD=11.42). Ninety-six percent of implants were stable at final radiographic follow up. Both reported complications involved acetabular cup loosening, requiring revision of the acetabular component.ConclusionThis study presents the largest cohort in the literature of patients who underwent THA with open triradiate cartilage. Our results highlight high patient reported outcomes and low revision rates at mid-term follow up. All patients had excellent implant fixation without radiographic signs of loosening at final radiographic follow up. These results support the use of THA in skeletally immature patients without the need to delay THA for closure of the triradiate cartilage.

PurposeIliopsoas tendinitis following total hip arthroplasty (THA) has been described to result from acetabular component overhang as well as prominent femoral collars. Yet, a portion of patients experience iliopsoas tendinitis in the setting of well-positioned components. The purpose of this study was to assess anatomic factors predisposing to iliopsoas tendinitis after THA.MethodsPatients with THAs performed at three academic institutions who subsequently underwent arthroscopic iliopsoas release were retrospectively reviewed from 2015 to 2025 and propensity matched in a 1:3 fashion to a control group of THAs without subsequent iliopsoas release. Controls were matched by age, surgery date, laterality, sex, surgical approach, and implanted femoral component. Patients with iliopsoas tendinitis and subsequent release (THA-IP) were evaluated for anterior acetabular component overhang and femoral collar overhang, when a collar was present. We also evaluated the absolute and relative profile of the lesser trochanter on anteroposterior radiographs, understanding that when less of the lesser trochanter is visualized, the trochanter is anatomically displaced posterolaterally, resulting in a more arduous route from the inner pelvic origin of the iliopsoas to its insertion on the femur.ResultsForty-five patients (mean age: 57±11; 71% female; 19 direct anterior, 10 anterolateral, 16 posterior approach) undergoing THA-IP were analyzed and matched to 135 controls. Both groups demonstrated a median cup size of 54 mm and head size of 36 mm. Average time to iliopsoas release after THA was 4 years. Anterior cup overhang of >2 mm was present in 49% of THA-IP patients, with 18% having collared femoral components, and 9% demonstrating collar overhang of >2 mm. Overall, 19 THA-IP patients had <2 mm of cup and collar overhang and 26 patients had >2 mm of overhang. THA-IP patients with <2 mm of cup and collar overhang had significantly greater relative posterolateralization of the lesser trochanter compared to those with overhang of >2 mm (p=0.010) and to controls (p=0.037).ConclusionVisualizing “Less of the Lesser” on anteroposterior hip radiographs and associated posterolateralization of the lesser trochanter may be an anatomic risk factor for iliopsoas tendinitis following THA, even in the presence of satisfactorily positioned components.

BackgroundOptimal treatment for iliopsoas tendinitis (IPTs) after total hip arthroplasty (THA) with cup malposition is controversial between iliopsoas release alone and cup revision especially in young active patients. Moreover, arthroscopic iliopsoas tendon (IPT) release in these patients has been rarely described and mid-term effect of this on THA longevity and recurrence of groin pain is unclear. We performed arthroscopic IPT release for IPTs after THA and report mid-term outcome in two young patients with acetabular cup malposition.Case SummaryTwo patients visited the hospital for groin pain which started early after THA. Both patients showed non-specific findings on physical examination and no evidence of infection on laboratory tests. X-ray and CT scans showed reduced acetabular component anteversion angle and anterior cup prominence more than 16 mm. As therapeutic diagnosis, ultrasonography-guided lidocaine injection with steroid into IPT sheath was performed. Initially, groin pain improved, but after a few months, it worsened in both patients. Therefore, we performed arthroscopic IPT release under spinal anesthesia. Arthroscopy revealed synovitis with fibrous tissues around IPT and various lesions related to the implants after THA. IPT tenotomy and debridement with biopsy were performed and histopathology showed chronic inflammation with synovial hyperplasia.Both patient were encouraged to start walking immediately after surgery and returned to complete daily life early after surgery without recurrence of groin pain and any implant-related problems at 9 years postoperatively.ConclusionArthroscopic IPT release showed excellent mid-term outcome without recurrence of groin pain and implant-related problems in those with cup malposition.

As robotic-assisted systems gain prominence in total hip arthroplasty (THA), their integration within Enhanced Recovery After Surgery (ERAS) pathways presents new opportunities for precision and early recovery. This retrospective study compared 104 patients undergoing THA performed either conventionally or assisted by the domestic ARTHROBOT robotic system under an ERAS protocol. While the robotic group experienced longer operative time and slightly longer incisions, it demonstrated significantly superior accuracy in component positioning. Acetabular component positioning was more accurate with ARTHROBOT assistance, achieving a 92.3% rate within the Lewinnek safe zone versus 75.0% conventionally, along with better control of leg length discrepancy and improved restoration of femoral and combined offsets. Although patients in the robotic group reported higher pain scores on postoperative day 3, this difference resolved by one month. Importantly, both groups achieved comparable outcomes in terms of early full weight-bearing time, hospital stay, functional recovery (Harris Hip Score, range of motion), complication rates, and high patient satisfaction (over 94%). The learning curve for the ARTHROBOT system was approximately 20 cases. These findings support the clinical integration of the domestic ARTHROBOT system in ERAS-based THA, enabling enhanced implant precision without compromising early safety or recovery.

To evaluate the feasibility and short-term effectiveness of three-dimensional (3D)-printed customized porous acetabular components for reconstruction of extensive acetabular bone defects during primary total hip arthroplasty (THA). The clinical data of 8 patients with extensive acetabular bone defects, who were treated with 3D-printed individualized porous acetabular components between July 2018 and January 2022, were retrospectively analyzed. The cohort comprised 4 males and 4 females with an average age of 48 years ranging from 34 to 56 years. Acetabular bone defects were classified as Paprosky type ⅢA in 3 cases and type ⅢB in 5 cases. The causes of acetabular destruction were hip tuberculosis (5 cases), pigmented villonodular synovitis (2 cases), and syphilitic arthritis (1 case). Visual analogue scale (VAS) score and Harris hip score (HHS) were used to evaluate the pain relief and hip function before and after operation. Reconstruction outcomes were further assessed by imaging results [X-ray film and Tomosynthesis Shimadzumetal artefact reduction technology (T-SMART)], and the mechanical properties were evaluated by finite element analysis. The operation time ranged from 174 to 195 minutes (mean, 187 minutes), and intraoperative blood loss ranged from 390 to 530 mL (mean, 465 mL). All 8 patients were follow-up 26-74 months (mean, 44 months). Among the 5 patients with tuberculosis, none experienced postoperative recurrence. At last follow-up, the VAS score was 0.3±0.5 and the HHS score was 87.9±3.7, both significantly improved compared to preoperative values ( t=25.170, P<0.001; t=-28.322, P<0.001). X-ray films at 2 years after operation demonstrated satisfactory matching between the 3D-printed customized acetabular component and the acetabulum. The postoperative center of rotation of the operated hip was shifted by (2.1±0.5) mm horizontally and (2.0±0.7) mm vertically relative to the contralateral side, with both offsets showing significant differences compared to preoperative values ( t=24.700, P<0.001; t=55.230, P<0.001). T-SMART imaging showed satisfactory osseointegration at the implant-host bone interface. No complications such as aseptic loosening or screw breakage was observed during follow-up. Finite element analysis showed that the acetabular component had good mechanical properties. The application of 3D-printed individualized porous acetabular components in the reconstruction of extensive acetabular bone defects demonstrated precise anatomical reconstruction, stable mechanical support, and good functional performance in short-term follow-up, offering a potential alternative for acetabular defect reconstruction in primary THA.