2026年3月 保髋进展 JCR Q1-2 区

BACKGROUND: Computed tomography (CT)-based, artificial intelligence (AI)-assisted three-dimensional (3D) preoperative planning is increasingly used to standardize component sizing and positioning in total hip arthroplasty (THA). In complex secondary hip osteoarthritis (HOA), perioperative burden and early recovery are particularly relevant to older or medically complex patients, yet it remains unclear whether etiology still shapes these outcomes under a unified planning pathway and single implant system. METHODS: This single-center retrospective cohort analyzed 95 consecutive cementless primary THAs for developmental dysplasia of the hip-associated HOA (DDH-HOA, RESULTS: Planning performance was comparable (cup match 59.62% vs. 65.12%; stem match 61.54% vs. 67.44%), with similar Lewinnek/Callanan safe-zone attainment and a median leg-length discrepancy (LLD) of 1 mm in both groups. Intraoperative blood loss was lower in DDH-HOA than in post-septic HOA (212.69 ± 62.31 vs. 243.72 ± 58.64 mL, CONCLUSION: Under a unified CT-based AI-assisted 3D planning pathway and single cementless system, sizing concordance and radiographic target attainment were similarly high across etiologies. By 24 months, PROMs were broadly comparable between groups. Post-septic sequelae were associated with greater intraoperative blood loss and less favorable pain and function at 1 month, supporting etiology-informed counseling and targeted perioperative risk mitigation.

BACKGROUND: Computed tomography (CT)-based, artificial intelligence (AI)-assisted three-dimensional (3D) preoperative planning is increasingly used to standardize component sizing and positioning in total hip arthroplasty (THA). In complex secondary hip osteoarthritis (HOA), perioperative burden and early recovery are particularly relevant to older or medically complex patients, yet it remains unclear whether etiology still shapes these outcomes under a unified planning pathway and single implant system. METHODS: This single-center retrospective cohort analyzed 95 consecutive cementless primary THAs for developmental dysplasia of the hip-associated HOA (DDH-HOA, RESULTS: Planning performance was comparable (cup match 59.62% vs. 65.12%; stem match 61.54% vs. 67.44%), with similar Lewinnek/Callanan safe-zone attainment and a median leg-length discrepancy (LLD) of 1 mm in both groups. Intraoperative blood loss was lower in DDH-HOA than in post-septic HOA (212.69 ± 62.31 vs. 243.72 ± 58.64 mL, CONCLUSION: Under a unified CT-based AI-assisted 3D planning pathway and single cementless system, sizing concordance and radiographic target attainment were similarly high across etiologies. By 24 months, PROMs were broadly comparable between groups. Post-septic sequelae were associated with greater intraoperative blood loss and less favorable pain and function at 1 month, supporting etiology-informed counseling and targeted perioperative risk mitigation.

BACKGROUND: During arthroscopic labral repair, anchors are inserted into the acetabular rim between 10- and 4-o'clock via multiple portals. This study evaluates METHODS: In stage one, 11 patients (22 hips) underwent skin marking of surface portals followed by 0.625 mm CT acquisition; Mimics reconstructed the bony model, and Autodesk Maya simulated anchor trajectories to define a preliminary safety zone. In stage two, six formalin-fixed specimens (12 hips) were equipped with 3-D-printed, patient-specific guides after portal marking, dissected, and instrumented at 10-4 o'clock positions. Anchors inserted via anterior, anterolateral, and DALA portals validated the virtual safety map, after which the refined data were applied prospectively in clinical application. RESULTS: Virtual anchoring revealed marked, position-dependent differences: the DALA portal at 12-o'clock achieved only 50.0% success, significantly below the anterolateral (86.4%) and anterior (90.9%) portals ( CONCLUSION: For arthroscopic labral repair, anchor placement should follow these portal-specific safe corridors: anterior portal-10, 11, 12, 1, 2, and 4 o'clock; anterolateral portal-10, 11, 12, and 2 o'clock; DALA portal-10, 11, 2, 3, and 4 o'clock.

PURPOSE: Focal labral ossification is a recognized radiographic finding in developmental dysplasia (DDH) and is typically regarded as a chronic lesion resulting from excessive stress on the chondro-labral junction. The necessity for direct surgical intervention at the time of periacetabular osteotomy (PAO) for these ossifications remains a subject of debate. This study aimed to explore the natural course of pre-existing focal labral ossifications following isolated PAO in adolescents and adults, hypothesizing that biomechanical correction alone would facilitate the spontaneous resolution of this focal labral metaplasia. METHODS: A retrospective observational subgroup analysis of an institutional database identified a single treatment group who underwent isolated PAO for symptomatic DDH in adolescents and adults between January 2022 and November 2024. Pre- and 1-year postoperative radiographs were independently assessed for the status of the labral ossification. Radiographic parameters of acetabular coverage and validated patient-reported outcome measures (PROMs) were compared between hips with and without ossification. Multivariable regression analysis was performed to identify factors associated with labral ossification. RESULTS: Of 389 hips undergoing PAO, 41 (10%) demonstrated preoperative labral ossification. Baseline PROMs and most radiographic parameters were comparable between hips with and without ossification, although posterior coverage was significantly reduced in the ossification group. At 1-year follow-up, 37 of 41 hips (90%) showed complete radiographic resolution of labral ossification, two hips (5%) demonstrated partial regression and two hips (5%) remained unchanged. Multivariable analysis identified a mild association between posterior coverage and the presence of ossification, while no associations were found with activity level or PROMs. CONCLUSION: Isolated PAO was found to be strongly associated with spontaneous remission of focal rim ossification in the vast majority of dysplastic hips within 1 year after surgery. These findings challenge the concept that focal rim ossifications represent irreversible degenerative pathology and instead suggest that they are a more appropriately interpreted as a metaplastic adaptation, indicating a remodeling potential of the chondro-labral junction following biomechanical correction alone. Routine surgical treatment of chronic labral ossifications at the time of PAO may therefore be unnecessary. LEVEL OF EVIDENCE: Level III.

Introduction We aimed to investigate compensatory alignment characteristics of coronal spinopelvic and lower limb alignments in patients with unilateral Crowe type IV developmental dysplasia of the hip (DDH). Methodology We conducted a cross-sectional study of 87 patients with unilateral Crowe type IV DDH at our hospital between September 2005 and August 2015. Using standing anteroposterior radiographs of the thoracic and lumbar spine, pelvis, and lower limbs, the inter-ankle height difference, mechanical axis percentage (%MA), leg length discrepancy, pelvic inclination, and Cobb angle were assessed. Spearman's rank correlation coefficient (ρ) was used to evaluate the associations between the inter-ankle height difference and other coronal spinopelvic and lower limb alignment parameters. For the relationships between the inter-ankle height difference and each alignment, multivariable linear regression analysis was performed to calculate adjusted β coefficients, controlling for age, sex, and body mass index. The inter-ankle height difference was treated as the dependent variable, and the other alignments were treated as independent variables. Results The mean age was 65.1 ± 8.6 years, and 77 patients (88.5%) were female. Spearman's rank correlation analysis demonstrated a significant positive weak correlation between the inter-ankle height difference and pelvic inclination (ρ = 0.335, p = 0.002). The inter-ankle height difference showed marginal significant weak association with %MA (ρ = 0.206, p = 0.055) and the Cobb angle (ρ = 0.192, p = 0.075). In contrast, no significant correlation was observed between the inter-ankle height difference and leg length discrepancy (ρ= 0.039, p = 0.721). In multivariate linear regression analysis, the inter-ankle height difference was significantly associated with pelvic inclination (adjusted β = 1.100, 95% CI 0.532-1.669) and Cobb angle (adjusted β = 0.330, 95% CI 0.039-0.620). No significant associations were observed with %MA or leg length discrepancy. Conclusion This cross-sectional study demonstrated that ankle-level compensation was significantly associated with pelvic inclination and showed a borderline association with spinal alignment in patients with unilateral Crowe type IV DDH, whereas knee alignment showed no robust association. These findings suggest that compensatory alignment changes for long-standing leg length discrepancy tend to be observed at the pelvic level, with secondary involvement of the spine rather than the knee.

OBJECTIVE: Hip arthroscopy for a painful endoprosthesis is performed to confirm and evaluate or detect pathologies (sampling for microbiology/histology, function), which are treated during the procedure or can indicate treatment options for the further course of the procedure. INDICATIONS: Hip arthroscopy is indicated for the diagnostics of unclear persistent pain after implantation of a hip endoprosthesis (low-grade infection, metal reaction/metallosis, loosening/misplacement of prosthesis components) and for treatment (iliopsoas impingement, removal of biomechanically disruptive osteophytes, removal of free joint bodies and cam impingement in hip resurfacing arthroplasty, arthrolysis in cases of restricted movement). CONTRAINDICATIONS: Local infections with the exception of the diagnostics of a low-grade infection, bone tumors near the joint, periprosthetic fractures and extensive periarticular ossification or arthrofibrosis with involvement of periarticular soft tissue (relative) are contraindications. SURGICAL TECHNIQUE: As with arthroscopy of native hip joints, the procedure is performed on a fracture table. Strict attention must be paid to precise positioning to avoid complications. Joint distraction is not performed in cases of an implanted endoprosthesis because no additional information can be expected from viewing the surfaces of the bearing couples and there is a risk of damaging the surfaces. Arthroscopy is carried out in the peripheral compartment in 10-30° flexion in the basic position via an anterolateral (AL) and anterior portal (A) as standard. Synovial fluid and tissue samples should be taken regularly for microbiological or histological examination. After adhesiolysis and synovectomy the exposed endoprosthesis is inspected and its function dynamically assessed. If iliopsoas impingement is present the release is performed using the transcapsular technique. POSTOPERATIVE MANAGEMENT: The postoperative treatment regimen includes pain-adapted mobilization with full weight-bearing after the day of the operation onwards. Crutches are indicated for ca. 5 days to harmonize the gait pattern. Physiotherapy exercises with permitted full range of motion are carried out from the 1st postoperative day and should generally be continued until the 6th postoperative week. RESULTS: In the period from 2010-2025, 22 hip arthroscopies were performed on 20 patients (14 female, 6 male; 2 female patients underwent arthroscopy twice) with an average age of 59 years (39-78 years) and an average of 3.5 years (0.75 months to 14.5 years) after arthroplasty. In each case 2 portals were created. The average operation time was 45 min (25-79 min). The results were evaluated after an average of 2.5 years (0.3-12.8 years), 4 patients underwent only diagnostic arthroscopy, an infection was detected twice and excluded two times. Of the infections one was treated with re-arthroscopy and one patient with an anterior cystic mass underwent an open reoperation. For the remaining 16 arthroscopies, overall 12 (75%) patients reported an improvement in preoperative symptoms. An iliopsoas release for impingement was performed 12 times. In 10 (83%) of these cases postoperative improvement with pain reduction was noted without any relevant loss of flexion strength. Mechanical joint symptoms were preoperatively present in 12 patients and were eliminated by the operation in 10 cases (83%). No complications were noted. ZUSAMMENFASSUNG: OPERATIONSZIEL: Die Hüftarthroskopie bei einliegender schmerzhafter Endoprothese erfolgt zur Bestätigung und Evaluation bzw. dem Auffinden von Pathologien (Probenentnahme Mikrobiologie/Histologie, Funktion), die im Rahmen des Eingriffs behandelt werden oder Therapieoptionen für den weiteren Verlauf aufzeigen können. INDIKATIONEN: Die Indikation zur Hüftarthroskopie besteht zur Diagnostik bei unklaren persistierenden Schmerzen nach Hüftendoprothesen-Implantation (Low-grade-Infekt, Metallreaktion/Metallose, Lockerung/Fehlplatzierung Prothesenkomponenten) und zur Therapie (Iliopsoas-Impingement, Abtragung biomechanisch störender Osteophyten, Entfernung freier Gelenkkörper und Cam-Impingement bei Oberflächenersatz-Endoprothese, Arthrolyse bei Bewegungseinschränkung). KONTRAINDIKATIONEN: Lokale Infektionen mit Ausnahme der Diagnostik des Low-grade-Infekts, gelenknahe Knochentumoren, periprothetische Frakturen und ausgedehnte periartikuläre Ossifikationen oder Arthrofibrose mit Beteiligung der periartikulären Weichteile (relativ) stellen Kontraindikationen dar. OPERATIONSTECHNIK: Analog zur Arthroskopie des nativen Hüftgelenks erfolgt der Eingriff auf einem Extensionstisch. Auf eine exakte Lagerung ist zur Vermeidung von Komplikationen strengstens zu achten. Bei einliegender Endoprothese wird auf eine Gelenkdistraktion verzichtet, weil durch Ansicht der Oberflächen der Gleitpaarungen keine Zusatzinformationen zu erwarten sind und die Möglichkeit besteht, die Oberflächen zu beschädigen. Es wird das periphere Kompartiment in 10° bis 30° Beugung in der Grundstellung standardmäßig über ein anterolaterales (AL) und anteriores (A) Portal arthroskopiert. Gelenkflüssigkeit und Gewebeproben zur mikrobiologischen bzw. histologischen Untersuchung sollten regelmäßig entnommen werden. Nach Adhäsiolyse und Synovektomie wird die freigelegte Endoprothese inspiziert und die Funktion dynamisch beurteilt. Bei vorliegendem Iliopsoas-Impingement erfolgt das Release in transkapsulärer Technik. WEITERBEHANDLUNG: Das Nachbehandlungsregime beinhaltet eine schmerzadaptierte Mobilisation mit Vollbelastung bereits ab dem Operationstag, Unterarmgehstützen sind zur Harmonisierung des Gangbilds für ca. 5 Tage angezeigt. Krankengymnastische Übungsbehandlungen mit erlaubtem vollem Bewegungsausmaß erfolgen ab dem 1. postoperativen Tag und sollten in der Regel bis zur 6. postoperativen Woche fortgeführt werden. ERGEBNISSE: Im Zeitraum von 2010–2025 wurden 22 Hüftarthroskopien bei einliegender Endoprothese bei 20 Patienten (14 weiblich, 6 männlich; 2 Patientinnen wurden zweimal arthroskopiert) mit einem Durchschnittsalter von 59 (39–78) Jahren durchschnittlich 3,5 (0,75–14,5 Monate) Jahre nach der Arthroplastik durchgeführt. Es wurden jeweils 2 Portale angelegt. Die durchschnittliche Operationszeit betrug 45 (25–79) min. Die Ergebnisevaluation erfolgte nach durchschnittlich 2,5 (0,3–12,8) Jahren. Vier Patienten wurden lediglich diagnostisch arthroskopiert, dabei wurde zweimal ein Infekt nachgewiesen, zweimal ausgeschlossen. Einer der Infekte wurde durch eine Re-Arthroskopie saniert. Bei einer Patientin mit zystischer anteriorer Raumforderung erfolgte im Verlauf eine offene Reoperation. Für die verbleibenden 16 Arthroskopien wurde insgesamt 12-mal (75 %) eine Besserung der präoperativen Beschwerdesymptomatik von den Patienten angegeben. Ein Iliopsoas-Release bei Impingement wurde 12-mal durchgeführt. In 10 (83 %) dieser Fälle war postoperativ eine Verbesserung mit Verringerung der Schmerzen zu verzeichnen, ohne dass ein relevanter Kraftverlust für die Beugung resultierte. Mechanische Gelenksymptome bestanden präoperativ bei 12 Patienten und konnten durch die Operation 10-mal (83 %) beseitigt werden. Komplikationen waren nicht zu verzeichnen.

BACKGROUND: Patients with femoroacetabular impingement (FAI) frequently experience sacroiliac joint (SIJ) pain. Patients with concomitant lower back symptoms may be at risk for poor patient-reported outcomes after cam resection. PURPOSE: To investigate whether SIJ stress in patients with FAI changes depending on posture or cam resection. STUDY DESIGN: Descriptive laboratory study. METHODS: Preoperative and postoperative computed tomography (CT) scans were analyzed in 31 patients with FAI who underwent cam resection. We created CT models of the lumbar spine, pelvis, and hip joints, including the SIJ cartilage and surrounding ligaments. For both pre- and postoperative conditions, we constructed models of standing, sitting, and sitting with 10° posterior pelvic tilt positions and measured the equivalent stress in the anterior, superior-posterior, and inferior-posterior regions of the SIJ under a 600-N load. RESULTS: Preoperatively, the equivalent stress in the posterior-inferior SIJ region was generally higher in the sitting than in the standing position (up to 2.87-fold, CONCLUSION: In patients with FAI, the equivalent stress in the lower portion of the SIJ generally increased in the sitting posture. Cam resection decreased the equivalent stress in the posterior-inferior SIJ region in the sitting posture to a level similar to that observed with a 10° posterior pelvic tilt before surgery. CLINICAL RELEVANCE: These findings suggest that optimizing pelvic posture and appropriate cam resection may help mitigate SIJ-related pain in patients with FAI, providing valuable insights for surgical planning and rehabilitation strategies.

BACKGROUND Crowe type IV developmental dysplasia of the hip (DDH) is characterized by complete proximal subluxation/dislocation of the femoral head, a small hypoplastic true acetabulum, and marked proximal femoral deformity. Total hip arthroplasty (THA) in Crowe IV DDH often requires femoral osteotomy for safe reduction. This retrospective study compared THA combined with low femoral neck osteotomy (LRNO) vs subtrochanteric osteotomy (SO). MATERIAL AND METHODS We reviewed 73 patients with Crowe IV DDH who underwent unilateral cementless THA from January 2017 to June 2024 (LRNO, n=37; SO, n=36). Primary outcomes were the Harris Hip Score (HHS) and Oxford Hip Score (OHS) at 12 months; scores were also assessed at 1, 3, and 6 months. Secondary outcomes included operative time, blood loss/transfusion, incision length, postoperative leg length discrepancy (LLD), perioperative laboratory changes, and complications. RESULTS Baseline characteristics were comparable (P>0.05). LRNO achieved higher HHS and OHS at 1 and 3 months (both P<0.001), with no between-group differences at 6 or 12 months (both P>0.05). LRNO had shorter operative time (P<0.001), smaller incision (P<0.001), less blood loss (P=0.002), lower transfusion requirements (blood, P<0.001; plasma, P=0.003), smaller postoperative LLD (P<0.001), and smaller decreases in hemoglobin and albumin (both P<0.001) than SO. Complication rates did not differ (P>0.05). CONCLUSIONS In Crowe IV DDH, THA with LRNO provides faster early functional recovery and improved perioperative efficiency with comparable 12-month function and short-term safety to SO.

OBJECTIVE: To determine whether tranexamic acid (TXA) reduces blood loss and transfusion rate in single-stage bilateral combined surgery for developmental dysplasia of the hip (DDH) in children. METHODS: A retrospective study was conducted on 148 children with bilateral DDH who underwent single-stage bilateral combined surgery between March 2021 and May 2025. Patients were categorized into a TXA group ( RESULTS: The TXA group exhibited significantly lower EBL compared with the control group (117.5 ± 7.7 mL vs. 171.4 ± 11.3 mL; CONCLUSIONS: TXA significantly reduces EBL and both total and intraoperative transfusion rates in children undergoing single-stage bilateral combined surgery for DDH, without affecting the risk of complications.

OBJECTIVE: Total hip arthroplasty (THA) improves function in patients with dysplastic hip osteoarthritis (DHOA). However, its effect on reducing fall risk remains unclear. This study aimed to evaluate fall risk following THA in patients with DHOA. METHODS: This retrospective cohort study included 85 patients who had DHOA and underwent THA between September 2019 and September 2022 and were evaluated as having a preoperative fall risk (Fall Risk Index 5 items [FRI-5] ≥ 6). They were categorized into two groups according to the FRI-5 score 1 year postoperatively. Evaluation parameters included FRI-5 score, age, sex, body mass index (BMI), Harris hip score (HHS), perceived leg length discrepancy (P-LLD), and radiographic parameters. Logistic regression was used to assess risk factors for postoperative falls. RESULTS: The FRI-5 score significantly decreased from 7.79 (6.0-13.0) preoperatively to 4.56 (0-13.0) postoperatively (p < 0.001). The number of falls during the year decreased from 36 (42.4%) to 18 (21.2%) after surgery (p = 0.005). The high-risk and low-risk groups comprised 33 and 52 individuals, respectively. The high-risk group was significantly older than the low-risk group (p = 0.006). Postoperative P-LLD was significantly large in the high-risk group compared to that in the low-risk group (p = 0.005). Preoperative and postoperative sagittal vertical axes (SVA) were significantly larger and preoperative lumbar lordosis (LL) was significantly lower in the high-risk group than in the low-risk group (p = 0.039, p = 0.034, and p = 0.021, respectively). Logistic regression analysis identified age (OR: 1.2, 95% CI: 1.05-1.36, p = 0.006), preoperative low LL (OR: 0.944, 95% CI: 0.892-0.999, p = 0.046), and postoperative P-LLD (OR: 5.81, 95% CI: 1.23-27.5, p = 0.026) as significant factors associated with fall risk. CONCLUSION: THA for patients who have DHOA at high risk of falls reduces the likelihood for falls. Therefore, surgeons should plan surgeries considering the risk factors post-THA.

BACKGROUND: Computed tomography (CT)-based, artificial intelligence (AI)-assisted three-dimensional (3D) preoperative planning is increasingly used to standardize component sizing and positioning in total hip arthroplasty (THA). In complex secondary hip osteoarthritis (HOA), perioperative burden and early recovery are particularly relevant to older or medically complex patients, yet it remains unclear whether etiology still shapes these outcomes under a unified planning pathway and single implant system. METHODS: This single-center retrospective cohort analyzed 95 consecutive cementless primary THAs for developmental dysplasia of the hip-associated HOA (DDH-HOA, RESULTS: Planning performance was comparable (cup match 59.62% vs. 65.12%; stem match 61.54% vs. 67.44%), with similar Lewinnek/Callanan safe-zone attainment and a median leg-length discrepancy (LLD) of 1 mm in both groups. Intraoperative blood loss was lower in DDH-HOA than in post-septic HOA (212.69 ± 62.31 vs. 243.72 ± 58.64 mL, CONCLUSION: Under a unified CT-based AI-assisted 3D planning pathway and single cementless system, sizing concordance and radiographic target attainment were similarly high across etiologies. By 24 months, PROMs were broadly comparable between groups. Post-septic sequelae were associated with greater intraoperative blood loss and less favorable pain and function at 1 month, supporting etiology-informed counseling and targeted perioperative risk mitigation.

BACKGROUND: The diagnosis of hip instability remains challenging because of its multifactorial etiology and the variability of imaging practices across institutions. Hip instability refers to a clinical condition of insufficient osseous and/or soft tissue constraint with abnormal femoral head motion and symptoms, which may occur along a morphologic spectrum that overlaps with-but is not synonymous with-developmental dysplasia of the hip. Although numerous imaging modalities and imaging parameters have been proposed, there is limited consensus on which are most relevant, how they should be measured, and what diagnostic thresholds best correlate with instability. To address this gap, a Delphi consensus study with an international panel of experts to establish standardized clinical statements for the diagnostic criteria of hip instability was conducted. QUESTIONS/PURPOSES: (1) What are the imaging modalities and protocols for investigating hip instability? (2) Which imaging parameters are most strongly associated with clinical hip instability? (3) What are the quantitative imaging thresholds for diagnosing hip instability? METHODS: A consensus study using a modified Delphi technique was conducted in accordance with the Accurate Consensus Reporting Document (ACCORD) guideline. Following a scoping review, 27 statements addressing imaging modalities and protocols (question 1), imaging parameters associated with hip instability (question 2), and quantitative imaging thresholds (question 3) were developed. These statements were evaluated by a multidisciplinary international expert panel during a structured consensus meeting, with two rounds of anonymous voting and consensus defined a priori as ≥ 75% agreement. Consensus was achieved for 81% (22 of 27) of statements. RESULTS: There was strong agreement that radiography (AP pelvis, false-profile, Dunn view) and MRI and CT constitute the foundational imaging modalities for the assessment of hip instability, whereas cartilage mapping techniques and dynamic ultrasound were considered adjunctive modalities with a more limited and evolving role. Radiographic measurements such as lateral center-edge angle (LCEA), anterior wall index (AWI), posterior wall index, and Tönnis angle reached consensus as key morphologic indicators. Several quantitative thresholds were endorsed. An LCEA of < 20° was considered diagnostic for hip dysplasia, a condition in which clinical hip instability is highly prevalent, whereas values between 20° and 25° were considered concerning for possible clinical hip instability. Additional thresholds included an AWI of < 0.30, PWI of < 0.8, and acetabular version < 5° or > 30°. In contrast, no consensus was reached for less-established imaging metrics such as the FEAR index, crescent sign, anterior capsule thickness, and dynamic femoral head translation. CONCLUSION: This international Delphi consensus defined core imaging approaches and threshold values for the evaluation of hip instability. Although agreement was reached on key morphometric parameters and diagnostic thresholds, a lack of consensus exists around newer soft tissue and dynamic measures, highlighting important areas for future research. CLINICAL RELEVANCE: In patients with suspected clinical hip instability, standard radiography should be used as the first-line imaging modality, followed by targeted use of CT and MRI to evaluate three-dimensional bony morphology and soft tissue stabilizers. Imaging findings should be interpreted within a stepwise, algorithmic framework that integrates clinical assessment with multiple complementary imaging parameters rather than relying on isolated measurements. Ultimately, accurate diagnosis of hip instability depends on the integration of findings from multiple modalities. Additionally, it must be recognized that hip instability may exist even in the absence of characteristic radiologic signs.

Optimal management of the capsule in hip arthroscopy continues to evolve. Historically, periportal capsulotomy has been considered the more difficult and time-consuming approach because of its limited visualization and the perceived learning curve. However, as our understanding of the importance of capsular integrity has grown, so has our prioritization of preserving its stabilizing function to prevent iatrogenic instability. Periportal capsulotomy techniques embody this shift by limiting capsular disruption while still allowing adequate visualization. Recent literature challenges long-held assumptions and demonstrates that periportal capsulotomy can lead to shorter operative times and faster recovery. When performed thoughtfully, the efficiency of periportal capsulotomy may be driven by avoiding the need for an extensive closure often required after larger capsulotomies. Periportal capsulotomy may not be the easiest technique to learn, but in the right hands it can be the more efficient and biologically respectful approach. It may be the mountain worth climbing in hip arthroscopy.

Excessive femoral anteversion is related to inferior patient reports outcomes after hiparthroscopy. While hip femoral acetabular impingement is a more common diagnosis, awareness of the importance of femoral version for prognosis following hip arthroscopy is growing. An algorithm for the practical assessment of clinically significant femoral version is proposed.

Developmental dysplasia of the hip (DDH), a morphological abnormality of the hip joint, is a well-recognized risk factor for hip osteoarthritis (OA). Much remains unknown about the genetic factors of DDH and its subtypes. To further understand its genetic basis, we conducted genome-wide association studies (GWASs) using a total of 1 085 Japanese DDH cases (including 788 hip dysplasia cases without dislocation and 297 cases with dislocated hip) and 24 000 controls. Additionally, we meta-analyzed with United Kingdom (UK) DDH GWAS and the largest hip OA GWAS to date. We identified three genome-wide significant novel loci, COL11A2, CALN1 and TRPM7, associated with hip dysplasia without dislocation. None of these signals were significant in dislocated hips, and additionally two of the signals had an opposite direction of association, suggesting distinct genetic architectures between the subtypes. The Japanese DDH GWAS identified five associated loci (VEGF-C, FOXC1, SMC2, SLC38A4, and TRPM7), and the trans-ancestry meta-analysis with UK revealed two loci (COL11A1 and GDF5) supported by strong trans-ancestry genetic correlation (r = 1.0). In total, nine loci were identified for DDH and its subtypes, with hip dysplasia without dislocation showing distinct genetic signals from hip dislocation. The meta-analysis of DDH and hip OA identified five novel signals for hip OA. Susceptibility loci and heritability enrichment analyses implicated pathways involving bone formation, collagen type XI trimer, and chondrocyte development, as well as their gene regulation, in DDH. These findings enhance understanding of the genetic architecture and biological pathways underlying DDH, providing new insights into its relationship with OA.

PURPOSE: To compare intraoperative findings associated with instability and clinical outcomes after hip arthroscopic femoroacetabular impingement syndrome (FAIS) surgery in patients with normal anteversion (NA) and excessive femoral anteversion (EA). METHODS: Inclusion criteria were FAIS cases who underwent primary arthroscopic management from January 2016 to December 2019. Patients who met exclusion criteria, such as osteoarthritis (Tonnis grade ≧ 2), and patients with less than a 2-year follow-up were excluded. The remaining hips were divided into 2 groups: the NA group (femoral anteversion 10°-25°) and the EA group (femoral anteversion > 25°). Clinical outcomes were assessed using the International Hip Outcome Tool 12 (iHOT12), hip outcome score activity of daily living scale (HOS-ADL), hip outcome score activity of sports (HOS-SP), and modified Harris hip score (mHHS). Achievement rates for the patient acceptable symptomatic state (PASS) and the minimal clinically important difference (MCID) were also evaluated. Intraoperative findings suggestive of instability were analyzed. RESULTS: The NA group included 34 hips, while the EA groups included 16 hips. Anteroinferior labral tears were significantly more prevalent in the EA group (75% vs 29.4%; P = .0051). Postoperative PROMs at 2 years were significantly worse in the EA group for iHOT12 (79.1 vs 95.1, P = .0017), HOS-ADL (91.2 vs 98.5, P = .0224), HOS-SP (83.3 vs 100, P = .0049), and mHHS (86.9 vs 96.8, P = .002). Regarding some PROMs, PASS achievement rates were also significantly lower in the EA group (iHot12: 56.2% vs 88.2%; P = .024, HOS-ADL: 62.5% vs 94.1%; P = .009), while no statistical difference was observed in MCID achievement rates. Three reoperations occurred in patients with EA, with femoral anteversion angles of 29°, 32.5°, and 33.5°. CONCLUSIONS: Patients with EA had inferior outcomes of hip arthroscopy and a higher prevalence of anteroinferior labral tears. LEVEL OF EVIDENCE: Level III, retrospective comparative case series.

BACKGROUND: Native hip instability encompasses a spectrum of abnormal pathomechanics under physiological loading and is associated with pain, dysfunction, and soft tissue damage. The condition spans a continuum-from developmental hip dysplasia to femoroacetabular impingement and even instability in the absence of bony deformities, as can be the case in patients with connective tissue disorders or soft tissue deficiencies. Despite advances in understanding this condition, biomechanical definitions, thresholds, and metrics remain inconsistent. We therefore sought to conduct a meeting with an international panel of experts to map available evidence on the biomechanical features of native hip instability, to identify knowledge gaps, and to explore whether current biomechanical metrics can reliably differentiate various degrees of severity of instability. QUESTIONS/PURPOSES: In this scoping review and structured consensus document, we asked: (1) What are the biomechanical or pathomechanical features of native hip instability? (2) What are the biomechanical metrics of hip instability? (3) Can biomechanical metrics differentiate between hip microinstability versus conventional (bony) instability? METHODS: A consensus study using the modified Delphi technique was conducted in accordance with the Accurate Consensus Reporting Document (ACCORD) guideline. The consensus meeting was held during the 15th Symposium on Joint Preserving and Minimally Invasive Surgery of the Hip, which took place in Québec City, Québec, Canada, in June 2025. The process involved a multidisciplinary steering committee and a diverse panel of 100 international participants representing 13 countries. Following a rapid scoping review, statements related to biomechanical or pathomechanical features of native hip instability and metrics of hip instability and hip microinstability were developed and sent to participants 1 week prior to the meeting. Participants voted on these statements across two Delphi rounds during the meeting, with consensus defined as ≥ 75% agreement. RESULTS: The anatomic features of instability were identified as follows: bony morphology, static soft tissue stabilizers of the labrum and joint capsule, and muscles as dynamic stabilizers. Reported metrics for instability included femoral head translation, with translation < 3 mm considered normal by consensus. There was insufficient evidence to differentiate between microinstability (ligamentous) and conventional (structural bony) instability. CONCLUSION: Biomechanically, native hip instability is characterized by an unpredictable femoral head path of motion influenced by bony morphology, capsulolabral integrity, and muscular stabilization. Femoral head translation was the most consistently supported metric, with translation < 3 mm considered physiological by consensus. Current biomechanical methods do not allow reliable differentiation between microinstability and structural instability. Standardized, reproducible in vivo measurements of three-dimensional hip motion are needed to establish clinically meaningful thresholds and guide patient care. CLINICAL RELEVANCE: Clinically, this study sets a biomechanical benchmark defining native hip instability, enabling researchers to better distinguish between physiological laxity and pathologic instability. By defining biomechanical features of hip instability-most notably femoral head translation > 3 mm-this work contributes to a more standardized approach for defining joint stability, integrating bony morphology, capsulolabral integrity, and muscular stabilization. Such biomechanical insights guide surgical decision-making regarding capsular management and soft tissue repair and inform targeted rehabilitation strategies aimed at restoring hip stability.