Intra-articular Osteoid Osteomas: Imaging Manifestations and Mimics.

Osteoid osteoma (OO) is the third most prevalent benign bone neoplasm in children. Although it predominantly affects the diaphysis of long bones, OO can assume an intra-articular location in the epiphysis or the intracapsular portions of bones. The most common location of intra-articular OO is the hip joint. The presentation of intra-articular OOs often poses a diagnostic enigma, both from clinical and radiologic perspectives. Initial symptoms are often vague and nonspecific, characterized by joint pain, stiffness, and limited range of motion, which frequently contributes to a delayed diagnosis. Radiographic findings range from normal to a subtle sclerotic focus, which may or may not have a lucent nidus. In contrast to their extra-articular counterparts, intra-articular lesions have distinct features at MRI, including synovitis, joint effusion, and bone marrow edema-like signal intensity. While CT remains the standard for identifying the nidus, even CT may be inadequate in visualizing it in some cases, necessitating the use of bone scintigraphy or fluorine 18-labeled sodium fluoride PET/CT for definitive diagnosis. Radiologists frequently play a pivotal role in suggesting this diagnosis. However, familiarity with the unique imaging attributes of intra-articular OO is key to this endeavor. Awareness of these distinctive imaging findings of intra-articular OO is crucial for avoiding diagnostic delay, ensuring timely intervention, and preventing unnecessary procedures or surgeries resulting from a misdiagnosis. The authors highlight and illustrate the different manifestations of intra-articular OO as compared with the more common extra-articular lesions with respect to clinical presentation and imaging findings. ©RSNA, 2024 Supplemental material is available for this article.

Application of AI-assisted MRI for the identification of surgical target areas in pediatric hip and periarticular infections.

OBJECTIVE: To develop an AI-assisted MRI model to identify surgical target areas in pediatric hip and periarticular infections. METHODS: A retrospective study was conducted on the pediatric patients with hip and periarticular infections who underwent Magnetic Resonance Imaging(MRI)examinations from January 2010 to January 2023 in three hospitals in China. A total of 7970 axial Short Tau Inversion Recovery (STIR) images were selected, and the corresponding regions of osteomyelitis (label 1) and abscess (label 2) were labeled using the Labelme software. The images were randomly divided into training group, validation group, and test group at a ratio of 7:2:1. A Mask R-CNN model was constructed and optimized, and the performance of identifying label 1 and label 2 was evaluated using receiver operating characteristic (ROC) curves. Calculation of the average time it took for the model and specialists to process an image in the test group. Comparison of the accuracy of the model in the interpretation of MRI images with four orthopaedic surgeons, with statistical significance set at P < 0.05. RESULTS: A total of 275 patients were enrolled, comprising 197 males and 78 females, with an average age of 7.10 ± 3.59 years, ranging from 0.00 to 14.00 years. The area under curve (AUC), accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 1 were 0.810, 0.976, 0.995, 0.969, 0.922, and 0.957, respectively. The AUC, accuracy, sensitivity, specificity, precision, and F1 score for the model to identify label 2 were 0.890, 0.957, 0.969, 0.915, 0.976, and 0.972, respectively. The model demonstrated a significant speed advantage, taking only 0.2 s to process an image compared to average 10 s required by the specialists. The model identified osteomyelitis with an accuracy of 0.976 and abscess with an accuracy of 0.957, both statistically better than the four orthopaedic surgeons, P < 0.05. CONCLUSION: The Mask R-CNN model is reliable for identifying surgical target areas in pediatric hip and periarticular infections, offering a more convenient and rapid option. It can assist unexperienced physicians in pre-treatment assessments, reducing the risk of missed and misdiagnosis.

Diagnostic and prognostic relevance of plain radiographs for periprosthetic joint infections of the hip: a literature review.

Conventional radiography is regularly used to evaluate complications after total hip arthroplasty. In various recent consensus meetings, however, plain radiographs of a potentially infected hip joint have been judged as being only relevant to exclude diagnoses other than infection. Solid data on radiographic presentations of periprosthetic joint infection (PJI) are scarce. As a result, the prognostic value of radiological features in low-grade PJI remains uncertain. The present review article aims to present an overview of the available literature and to develop ideas on future perspectives to define the diagnostic possibilities of radiography in PJIs of the hip. The primary outcome of interest of this systematic review was the radiologic presentation of periprosthetic joint infections of the hip. As secondary outcome of interest served the sensitivity and specificity of the radiologic presentation of periprosthetic joint infections. Of the included articles, 26 were reviews, essays, or case reports and only 18 were clinical studies. Typical radiologic abnormalities of PJI were a periosteal reaction, a wide band of radiolucency at the cement-bone or metal-bone interface, patchy osteolysis, implant loosening, bone resorption around the implant, and transcortical sinus tracts. The frequency of their occurrence is still inadequately defined. A deeper understanding of the underlying causes and the relation between microorganisms to radiologic abnormalities can probably help clinicians in the future to diagnose a PJI. This is why further research shall focus on the radiographic features of PJI.

Use of a fluoroscopy-based robotic-assisted total hip arthroplasty system resulted in greater improvements in hip-specific outcome measures at one-year compared to a CT-based robotic-assisted system.

BACKGROUND: The purpose of this study was to compare one-year patient reported outcome measures between a novel fluoroscopy-based robotic-assisted (FL-RTHA) system and an existing computerised tomography-based robotic assisted (CT-RTHA) system. METHODS: A review of 85 consecutive FL-RTHA and 125 consecutive CT-RTHA was conducted. Outcomes included one-year post-operative Veterans RAND-12 (VR-12) Physical (PCS)/Mental (MCS), Hip Disability and Osteoarthritis Outcome (HOOS) Pain/Physical Function (PS)/Joint replacement, and University of California Los Angeles (UCLA) Activity scores. RESULTS: The FL-RTHA cohort had lower pre-operative VR-12 PCS, HOOS Pain, HOOS-PS, HOOS-JR, and UCLA Activity scores compared with patients in the CT-RTHA cohort. The FL-RTHA cohort reported greater improvements in HOOS-PS scores (-41.54 vs. -36.55; p = 0.028) than the CT-RTHA cohort. Both cohorts experienced similar rates of major post-operative complications, and had similar radiographic outcomes. CONCLUSIONS: Use of the fluoroscopy-based robotic system resulted in greater improvements in HOOS-PS in one-year relative to the CT-based robotic technique.

Regional Anesthesia for Hip Arthroscopy.

Pain after hip arthroscopy can be severe, yet we lack a consensus method for non-narcotic analgesia. Here we describe anatomic elements of hip arthroscopy and our current understanding of the relevant sensory innervation as a prelude to the evaluation of locoregional analgesic techniques. Many regional nerve blocks and local anesthetic infiltration techniques are reviewed, including 2 newer ultrasound fascial plane blocks. Further study of targeted, motor-sparing approaches, either ultrasound-guided or under direct surgical visualization is needed.

Morphological features of the acetabulum with coxa profunda in women: a retrospective observational study.

BACKGROUND: The morphology of coxa profunda remains inadequately understood. However, knowledge about the characteristics of the acetabulum in coxa profunda can help to predict pelvic morphology in three dimensions based on radiographic findings, as well as help to diagnose and predict hip pathologies. Therefore, this study aimed to investigate the relationship between the morphological characteristics of the pelvis and coxa profunda. METHODS: We conducted a retrospective analysis including women who had undergone unilateral total hip arthroplasty. Only those with normal hip joint morphology on the opposite side, as evidenced by anteroposterior pelvic radiography showing a distance of ≥ 2 mm between the ilioischial line and acetabular floor, were included. Five parameters related to acetabular anteversion, thickness, and the position of the ilioischial line were measured using axial computed tomography at the central hip joint. The coxa profunda group (n = 39) and control group (n = 34) were compared. RESULTS: The mean acetabular anteversion angle was 12.5° ± 4° in the control group and 22.3° ± 5.6° in the coxa profunda group. The mean thickness from the acetabular fossa to the medial wall was 7.5 ± 1.7 mm in the control group and 3.9 ± 1.2 mm in the coxa profunda group. Furthermore, the bony region representing the ilioischial line was positioned more posteriorly in the coxa profunda group than it was in the control group. CONCLUSION: Our findings suggest that coxa profunda in women is associated with anterior acetabular dysplasia and a thin acetabulum, in contrast to previous interpretations of excessive coverage. This insight suggests a conversion of coxa profunda from a finding of pincer-type femoroacetabular impingement to a finding of acetabular dysplasia, a revelation that also draws attention to cup positioning for total hip arthroplasty.

Indirect Head of the Rectus Femoris Tendon as a Graft for Segmental Hip Labral Reconstruction: An Anatomic, Radiographical, and Biomechanical Study in Comparison With Iliotibial Labral Reconstruction.

BACKGROUND: The indirect head of the rectus femoris (IHRF) tendon has been used as an autograft for segmental labral reconstruction. However, the biomechanical properties and anatomic characteristics of the IHRF, as they relate to surgical applications, have yet to be investigated. PURPOSE: To (1) quantitatively and qualitatively describe the anatomy of IHRF and its relationship with surrounding arthroscopically relevant landmarks; (2) detail radiographic findings pertinent to IHRF; (3) biomechanically assess segmental labral reconstruction with IHRF, including restoration of the suction seal and contact pressures in comparison with iliotibial band (ITB) reconstruction; and (4) assess potential donor-site morbidity caused by graft harvesting. STUDY DESIGN: Descriptive laboratory study. METHODS: A cadaveric study was performed using 8 fresh-frozen human cadaveric full pelvises and 7 hemipelvises. Three-dimensional anatomic measurements were collected using a 3-dimensional coordinate digitizer. Radiographic analysis was accomplished by securing radiopaque markers of different sizes to the evaluated anatomic structures of the assigned hip.Suction seal and contact pressure testing were performed over 3 trials on 6 pelvises under 4 different testing conditions for each specimen: intact, labral tear, segmental labral reconstruction with ITB, and segmental labral reconstruction with IHRF. After IHRF tendon harvest, each full pelvis had both the intact and contralateral hip tested under tension along its anatomic direction to assess potential site morbidity, such as tendon failure or bony avulsion. RESULTS: The centroid and posterior apex of the indirect rectus femoris attachment are respectively located 10.3 ± 2.6 mm and 21.0 ± 6.5 mm posteriorly, 2.5 ± 7.8 mm and 0.7 ± 8.0 mm superiorly, and 5.0 ± 2.8 mm and 22.2 ± 4.4 mm laterally to the 12:30 labral position. Radiographically, the mean distance of the IHRF to the following landmarks was determined as follows: anterior inferior iliac spine (8.8 ± 2.5 mm), direct head of the rectus femoris (8.0 ± 3.9 mm), 12-o'clock labral position (14.1 ± 2.8 mm), and 3-o'clock labral position (36.5 ± 4.4 mm). During suction seal testing, both the ITB and the IHRF reconstruction groups had significantly lower peak loads and lower energy to peak loads compared with both intact and tear groups (P = .01 to .02 for all comparisons). There were no significant differences between the reconstruction groups for peak loads, energy, and displacement at peak load. In 60° of flexion, there were no differences in normalized contact pressure and contact area between ITB or IHRF reconstruction groups (P > .99). There were no significant differences between intact and harvested specimen groups in donor-site morbidity testing. CONCLUSION: The IHRF tendon is within close anatomic proximity to arthroscopic acetabular landmarks. In the cadaveric model, harvesting of the IHRF tendon as an autograft does not lead to significant donor-site morbidity in the remaining tendon. Segmental labral reconstruction performed with the IHRF tendon exhibits similar biomechanical outcomes compared with that performed with ITB. CLINICAL RELEVANCE: This study demonstrates the viability of segmental labral reconstruction with an IHRF tendon and provides a detailed anatomic description of the tendon in the context of an arthroscopic labral reconstruction. Clinicians can use this information during the selection of a graft and as a guide during an arthroscopic graft harvest.

Unilateral avascular necrosis of the right hip in an HIV patient with tearing of the rectus femoris and adductor longus muscles.

A man in his 20s with a medical history of syphilis, chlamydia and HIV presented to the emergency department (ED) with 2 months of right hip pain and was found to have advanced avascular necrosis (AVN) of the right femoral head with secondary haemorrhage. The patient lacked the common risk factors of AVN in patients with HIV (PWH): ≥10 years of HIV diagnosis, extended duration on highly active antiretroviral therapy, trauma, corticosteroid use, alcohol abuse, systemic lupus erythematosus, obesity, smoking and dyslipidaemia. Given the extensive destructive changes in the hip joint and muscles, a right hip resection arthroplasty was performed, and the patient recovered well postoperatively. This case presents a learning opportunity for understanding bone pathologies in PWH and offers clinical guidance for the management of HIV-infected patients with a focus on optimising bone health.

Effect of Spinopelvic Parameters on Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

BACKGROUND: Spinopelvic parameters, including pelvic tilt (PT), sacral slope (SS), and pelvic incidence, have been developed to characterize the relationship between lumbar spine and hip motion, but a paucity of literature is available characterizing differences in spinopelvic parameters among patients with femoroacetabular impingement syndrome (FAIS) versus patients without FAIS, as well as the effect of these parameters on outcomes of arthroscopic treatment of FAIS. PURPOSE: To (1) identify differences in spinopelvic parameters between patients with FAIS versus controls without FAIS; (2) identify associations between spinopelvic parameters and preoperative patient-reported outcomes (PROs); and (3) identify differences in PROs between patients with stiff spines (standing-sitting ΔSS ≤10°) versus those without. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The study enrolled patients ≥18 years of age who underwent primary hip arthroscopy for treatment of FAIS with cam, pincer, or mixed (cam and pincer) morphology. Participants underwent preoperative standing-sitting imaging with a low-dose 3-dimensional radiography system and were matched on age and body mass index (BMI) to controls without FAIS who also underwent EOS imaging. Spinopelvic parameters measured on EOS films were compared between the FAIS and control groups. Patients with FAIS completed the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) before surgery and at 1-year follow-up. Outcome scores were compared between patients with stiff spines versus those without. Associations between spinopelvic parameters and baseline outcome scores were assessed with Pearson correlations. Continuous variables were compared with Student t test and/or Mann-Whitney U test, and categorical variables were compared with Fisher exact test. RESULTS: A total of 50 patients with FAIS (26 men; 24 women; mean age, 36.1 ± 10.7 years; mean BMI, 25.6 ± 4.2) were matched to 30 controls without FAIS (13 men; 17 women; mean age, 36.6 ± 9.5 years; mean BMI, 26.7 ± 3.6). Age, sex, and BMI were not significantly different between the FAIS and control groups (P > .05). Standing PT was not significantly different between stiff and non-stiff cohorts (P = .73), but sitting PT in the FAIS group was more than double that of the control group (36.5° vs 15.0°; P < .001). Incidence of stiff spine was significantly higher in the FAIS group (62.0% vs 3.3%; P < .001). Among FAIS patients, those with stiff spines had a significantly higher prevalence of cam impingement, whereas those with non-stiff spines had a higher prevalence of mixed impingement (P = .04). No significant differences were seen in preoperative mHHS or NAHS scores or pre- to postoperative improvement in scores between FAIS patients with stiff spines versus those without (P > .05), but a greater sitting SS was found to be positively correlated with a higher baseline mHHS (r = 0.36; P = .02). CONCLUSION: Patients with FAIS were more likely to have a stiff spine (standing-sitting ΔSS ≤10°) compared with control participants without FAIS. FAIS patients with stiff spines were more likely to have isolated cam morphology than patient without stiff spines. Although sitting SS was positively correlated with baseline mHHS, no significant differences were seen in 1-year postoperative outcomes between FAIS patients with versus without stiff spine.

Septic arthritis of the native hip joint and septic pulmonary embolism in an adult with sickle cell trait after a complicated dental extraction.

Septic arthritis (SA) is a serious infection of the joint which can lead to irreversible destruction of the joint.We report a case of right hip SA with septic pulmonary embolism following a complicated dental extraction in a woman in her early 40s with sickle cell trait (SCT).The patient presented with severe right thigh pain and left jaw pain.Initial workup revealed raised C reactive protein and positive blood cultures. Right hip joint SA was confirmed following intraoperative joint aspiration. The patient had right hip debridement with long-term intravenous antibiotics.The incidence of SA in adults with sickle cell disease is low: 0.3% in a study in France and Brazil and 10.3% incidence of haematogenous osteoarticular infection in children with SCT in West Africa.

Sex-based differences in neck selectivity in total hip arthroplasty using a modular femoral neck system.

BACKGROUND: Dislocation is a major complication of total hip arthroplasty (THA). The modular femoral neck system provides practical advantages by allowing adjustment of neck version and length in the presence of intraoperative instability. Anatomical studies have identified morphological differences in the hip joint between men and women. Despite sex-based differences in hip morphology, it remains unclear whether such differences affect neck selectivity in THA using a modular neck system and whether this approach achieves anatomical reconstruction, thereby reducing complications such as dislocation. This study aimed to investigate gender differences in neck selectivity in THA with the modular neck system and assess the clinical impact of the modular neck system. METHODS: A total of 163 THAs using a modular neck system were included in this study. Data on the type of modular neck and intraoperative range of motion (ROM) were retrieved from patient records. Pre- and post-operative leg length differences (LLD) were examined as part of the radiographic assessment. Dislocation was investigated as a postoperative complication. RESULTS: Neck selectivity did not significantly differ between men and women. The comparison of pre- and post-operative LLD revealed a tendency for varus necks to improve LLD more than version-controlled necks. Furthermore, no significant correlation was found between intraoperative ROM and neck selectivity, or postoperative dislocation and neck selectivity. CONCLUSIONS: This study on THA with a modular neck system provided valuable insights into sex-based differences in neck selectivity and highlighted the potential benefits of the modular neck system in addressing LLD and preventing postoperative dislocation.

Accuracy of conventional motion capture in measuring hip joint center location and hip rotations during gait, squat, and step-up activities.

Accurate measurements of hip joint kinematics are essential for improving our understanding of the effects of injury, disease, and surgical intervention on long-term hip joint health. This study assessed the accuracy of conventional motion capture (MoCap) for measuring hip joint center (HJC) location and hip joint angles during gait, squat, and step-up activities while using dynamic biplane radiography (DBR) as the reference standard. Twenty-four young adults performed six trials of treadmill walking, six body-weight squats, and six step-ups within a biplane radiography system. Synchronized biplane radiographs were collected at 50 images per second and MoCap was collected simultaneously at 100 images per second. Bone motion during each activity was determined by matching digitally reconstructed radiographs, created from subject-specific CT-based bone models, to the biplane radiographs using a validated registration process. Errors in estimating HJC location and hip angles using MoCap were quantified by the root mean squared error (RMSE) across all frames of available data. The MoCap error in estimating HJC location was larger during step-up (up to 89.3 mm) than during gait (up to 16.6 mm) or squat (up to 31.4 mm) in all three anatomic directions (all p < 0.001). RMSE in hip joint flexion (7.2°) and abduction (4.3°) during gait was less than during squat (23.8° and 8.9°) and step-up (20.1° and 10.6°) (all p < 0.01). Clinical analysis and computational models that rely on skin-mounted markers to estimate hip kinematics should be interpreted with caution, especially during activities that involve deeper hip flexion.

Comparison of quality and interpretation of newborn ultrasound screening examinations for developmental dysplasia of the hip by basically trained nurses and junior physicians with no previous ultrasound experience.

BACKGROUND: We are obliged to give babies the chance to profit from a nationwide screening of developmental dysplasia of the hip in very rural areas of Mongolia, where trained physicians are scarce. This study aimed to compare the quality and interpretation of hip ultrasound screening examinations performed by nurses and junior physicians. METHODS: A group of 6 nurses and 6 junior physician volunteers with no previous ultrasound experience underwent Graf's standard training in hands-on practice. Newborns were examined before discharge from the hospital, according to the national guideline. Two standard documentation images of each hip were saved digitally. The groups were compared on the proportion of good quality of sonograms and correct interpretation. Two Swiss supervisors' agreed diagnosis according to Graf was considered the final reference for the study purposes. RESULTS: A total of 201 newborns (402 hips or 804 sonograms) were examined in the study, with a mean age of 1.3±0.8 days at examination. Junior physicians examined 100 newborns (200 hips or 400 sonograms), while nurses examined 101 newborns (202 hips or 404 sonograms). The study subjects of the two groups were well balanced for the distribution of baseline characteristics. The study observed no statistically significant difference in the quality of Graf's standard plane images between the providers. Eventually, 92.0% (92) of the physician group and 89.1% (90) of the nurse group were correctly diagnosed as "Group A" (Graf's Type 1 hip) or "Non-Group A" hips (p = 0.484). The most common errors among the groups were a missing lower limb, wrong measurement lines, and technical problems. CONCLUSION: Our study provides evidence that while there might be a trend of slightly more technical mistakes in the nurse group, the overall diagnosis accuracy is similar to junior physicians after receiving standard training in Graf's hip ultrasound method. However, after basic training, regular quality control is a must and all participants should receive refresher trainings. More specifically, nurses need training in the identification of anatomical structures.

Effective Stretching Positions of the Piriformis Muscle Evaluated Using Shear Wave Elastography.

CONTEXT: Piriformis syndrome is often associated with muscle spasms and shortening of the piriformis muscle (PM). Physical therapy, including static stretching of the PM, is one of the treatments for this syndrome. However, the effective stretching position of the PM is unclear in vivo. This study aimed to determine the effective stretching positions of the PM using ultrasonic shear wave elastography. DESIGN: Observational study. METHODS: Twenty-one healthy young men (22.7 [2.4] y) participated in this study. The shear elastic modulus of the PM was measured at 12 stretching positions using shear wave elastography. Three of the 12 positions were tested with maximum internal rotation at 0°, 20°, or 40° hip adduction in 90° hip flexion. Nine of the 12 positions were tested with maximum external rotation at positions combined with 3 hip-flexion angles (70°, 90°, and 110°) and 3 hip-adduction angles (0°, 20°, and 40°). RESULTS: The shear elastic modulus of the PM was significantly higher in the order of 40°, 20°, and 0° of adduction and higher in external rotation than in internal rotation. The shear elastic modulus of the PM was significantly greater in combined 110° hip flexion and 40° adduction with maximum external rotation than in all other positions. CONCLUSION: This study revealed that the position in which the PM was most stretched was maximum external rotation with 110° hip flexion and 40° hip adduction.

Neurogenic heterotopic ossification of the hip: Magnetic resonance imaging versus computed tomography for pre-surgical assessment.

PURPOSE: Neurogenic heterotopic ossification (NHO) of the hip is a frequent complication of spinal cord injuries, often requiring surgical management. Pre-surgical imaging assessment is essential, usually with computed tomography (CT)-scan. We aimed to compare magnetic resonance imaging (MRI) and CT for pre-surgical imaging assessment of the NHO, particularly for their relationships with vessels and nerves. METHOD: This prospective study included consecutive patients who underwent surgery for NHO from July 2019 to April 2022. All patients had CT angiography and MRI including Zero Echo Time and TRICKS sequences. Radiologists used standardized reports for CT and MRI to evaluate NHO and their features, bone mineralization, and relation to the arteries, veins and nerves. Agreement between pre-surgical CT and MRI was evaluated. RESULTS: Twenty-four patients (mean age: 53.5 ± 12.2 years) were included, among which 7 had bilateral NHO (31 hips). NHO were anterior in 15/31 hips (48 %), multifragmented in 25/31 hips (81 %). Mild and significant demineralization was most frequent. Gutter and tunnel were reported in 11.1 % of the arteries. Nerves were more often identified in MRI than in CT-scan. Agreement coefficients between CT and MRI were excellent for NHO location (0.95) and implantation (0.92), good for fragmentation (0.70), contact with joint capsule (0.66), bone mineralization (0.74), and relation to arteries (0.85), veins (0.76), sciatic nerve (0.7) and moderate for femoral nerve (0.47). CONCLUSION: MRI exhibited a good agreement with CT for pre-surgical assessment of NHO of the hip, especially to evaluate their relationships with the arteries, veins and sciatic nerve. Femoral nerves were more often identified in MRI than in CT-scan.

Influence of acetabular and femoral morphology on pelvic tilt.

Aims: The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors? Methods: This was an institutional review board-approved, single-centre, retrospective, case-control, comparative study, which included 388 symptomatic hips in 357 patients who presented to our tertiary centre for joint preservation between January 2011 and December 2015. Their mean age was 26 years (SD 2; 23 to 29) and 50% were female. They were allocated to 12 different morphological subgroups. The study group was compared with a control group of 20 asymptomatic hips in 20 patients. APP-PT was assessed in all patients based on supine anteroposterior pelvic radiographs using validated HipRecon software. Values in the two groups were compared using an independent-samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. The minimal clinically important difference (MCID) for APP-PT was defined as > 1 SD. Results: There were no significant differences in APP-PT between the control group and the overall group (1.1° (SD 3.0°; -4.9° to 5.9°) vs 1.8° (SD 3.4°; -6.9° to 13.2°); p = 0.323). Acetabular retroversion and overcoverage groups showed higher mean APP-PTs compared with the control group (p = 0.001 and p = 0.014) and were the only diagnoses with a significant influence on APP-PT in the stepwise multiple regression analysis. All differences were below the MCID. The age, sex, height, weight, and BMI showed no influence on APP-PT. Conclusion: APP-PT showed no radiologically significant variation across different pathomorphologies of the hip in patients being assessed for joint-preserving surgery.

[Clinical value of high frequency ultrasound in the diagnosis of hip joint involvement in patients with ankylosing spondylitis].

OBJECTIVE: To analyze the correlation between hip joint musculoskeletal ultrasound score and ankylosing spondylitis (AS) disease activity, as well as to investigate the value of high frequency ultrasound in the assessment of hip joint involvement in AS. METHODS: The clinical data of 244 patients with AS who were treated in the rheumatology department of from March 2019 to March 2022 were retrospectively analyzed. Among them, there 174 males and 70 females, aged from 19 to 58 years old with an average of (34.22±9.49) years old;the disease duration of AS patients ranged from 8 months to 26 years, with an average of (13.68±4.04) years.The 244 patients were divided into disease group (83 cases) and control group (161 cases) based in the presence of hip joint involuement. According to the the disease activity, patients in the disease group were further categorezed into active phase (45 cases) and stable phase (38 cases). The ultrasound scores of patients in the active and stable phases of the disease group and the control group were compared. Relevant factors of hip joint involvement in AS patients were analyzed, and analyze the correlation between ultrasound score and Bath ankylosing spondylitis disease activity score index(BASDAI), Bath ankylosing spondylitis functional index(BASFI), visual analogue score of pain (VAS), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and the correlation between hip joint capsule score and tendon attachment end score and BASDAI, BASFI, VAS, CRP and ESR. RESULTS: The hip joint capsule score(3.06±1.12), femoral head score(1.45±0.43), tendon attachment end score(3.28±1.30) and total ultrasound score(6.65±2.31) of the disease group were higher than those of the control group(1.51±0.48)、(0.66±0.27)、(1.61±0.53)、(3.81±1.44)scores (P<0.05). Multifactor Logstic regression analysis showed that the course of disease, hip joint capsule score and total ultrasound score were independent risk factors for hip involvement in AS patients.The hip capsule score (3.65±1.22)and total ultrasound score(8.28±2.33) in the active phase of the disease group were higher than those in the stable phase (2.48±1.04)、( 6.82±1.96)scores(P<0.05). The hip joint capsule score and total ultrasonic score of AS patients were positively correlated with BASDAI, BASFI, VAS, CRP, and ESR (P<0.05, P<0.01).The score of tendon attachment end was positively correlated with CRP (P<0.05). The score of joint capsule effusion in AS patients was positively correlated with BASDAI, BASFI and VAS (P<0.05, P<0.01). The synovial blood flow score was positively correlated with BASDAI, VAS, CRP and ESR (P<0.05, P<0.01). The synovial thickening score was positively correlated with BASDAI, BASFI, VAS, CRP and ESR (P<0.05, P<0.01). There was no correlation between the score of tendon attachment end and BASDAI, BASFI, VAS, CRP and ESR. CONCLUSION: There is a correlation between hip joint ultrasonic score of hip joint and clinical indexes in AS patients.Hip joint capsule score and total ultrasonic score were independent risk factors for hip involvement in AS patients. High frequency ultrasound exhibits clinical value in the diagnosis of hip joint involvement in AS patients.

Prevalence of Acetabular Dysplasia at a Mean age of 18 Years After Treatment for Neonatal hip Instability.

BACKGROUND: The long-term radiological outcomes after the treatment of neonatal hip instability (NHI) in developmental dysplasia of the hip are unclear. Therefore, the prevalence of acetabular dysplasia at a mean age of 18 years after treatment was investigated. The relationship between acetabular dysplasia and hip discomfort has also been poorly established. Therefore, the differences in pain, hip-related quality of life (QOL), and hip impingement tests in hips with and without acetabular dysplasia were assessed. METHODS: All 127 patients treated for NHI from 1995 to 2001 at the study hospital and meeting the inclusion criteria were invited to participate in this population-based follow-up. Of these individuals, 88 (69.3%) participated. The lateral center-edge angle (LCEA), Sharp's angle (SA), and acetabular head index (AHI) were calculated for both hips from pelvic anterior-posterior radiographs. The Copenhagen Hip and Groin Outcome Score (HAGOS) questionnaire was completed for both hips separately; the total score, pain, and QOL subscores were calculated; and the impingement test was performed. RESULTS: The prevalence of acetabular dysplasia, defined as an LCEA <20°, was 3.4%. Only the mean AHI (81.1%, SD 5.3) differed (-5.08, 95% CI -5.77 to -4.38, P <0.001) from previously described gender-specific and side-specific means, whereas the mean LCEA and SA did not. The odds ratio for a positive hip impingement test was 2.8 (95% CI: 1.11-7.05, P = 0.029) for hips with an LCEA <25° compared to hips with LCEA ≥25°. The hips with an SA ≥45° had a mean of 7.8 points lower for the HAGOS pain subscore (95% CI: 4.2-11.4, P <0.001) and a mean of 6.1 points lower for the HAGOS QOL subscore (95% CI: 2.1-10.2, P = 0.003) compared with hips with an SA <45°. CONCLUSIONS: The prevalence of acetabular dysplasia was low after treatment for NHI. Acetabular dysplasia seems to be as common in the general population as for those treated for NHI based on the LCEA. Only an SA ≥45° resulted in slightly more pain and lower hip-related QOL.

Analysis on association between sagittal stem alignment and early functional and radiological outcome following primary cementless total hip replacement.

INTRODUCTION: Accurate reconstruction of hip anatomy and biomechanics is mandatory for achieving good clinical outcomes following total hip replacement (THR). Optimal stem alignment is essential to avoid impingement or loosening. This study aimed to evaluate sagittal stem position following cementless THR and its relationship with patient's functional outcome and post-operative radiological parameters. METHOD: We performed analytical observational study with cross-sectional design on 71 hips (67 patients, ranged 18-85 years old) that underwent primary cementless THR in two orthopedic centers in Jakarta, Indonesia. All hips were operated through either anterolateral or posterior approach using either extended/full-coating wedge-tapered stem or proximal-coated wedge-tapered stem. Clinical outcomes were evaluated at follow-up time using mHHS questionnaire, VAS level of thigh pain, and hip ROM. Stem sagittal alignment and other radiological parameters, including combined anteversion and offset, were measured from conventional radiograph. RESULTS: There were no significant differences on mHHS score, VAS level on thigh pain, and ROM between stem alignment groups. Post-operative anteversion and offset of the implant were not affected by the stem sagittal position. All influencing factors have significant effect on sagittal stem alignment. Linear regression test on femur morphology showed 0.69° increase in stem posterior tilt for every 1° increase in the anterior bowing (coeff. = 0.502). CONCLUSION: Stem tilting in sagittal plane did not affect patient's functional outcome or post-operative radiological parameters. In addition, for every degree of increased anterior femoral bowing, 0.69° increase in posterior stem tilting can be expected.

Which method should we use to determine the hip joint center location in individuals with a high amount of soft tissue?

BACKGROUND: This study investigated the most accurate method for estimating the hip joint center position in clinical 3D gait analysis for young individuals with high amounts of soft tissue. We compared position estimates of five regression-based and two functional methods to the hip joint center position obtained through 3D free-hand ultrasound. METHODS: For this purpose, the data of 14 overweight or obese individuals with a mean age of 13.6 (SD 2.1 yrs) and a BMI of 36.5 (SD 7.1 kg/m2, range 26-52 kg/m2) who underwent standard clinical 3D gait analysis were used. The data of each participant were processed with five regression-based and two functional methods and compared to the hip joint center identified via 3D free-hand ultrasound. FINDINGS: The absolute location errors to 3D free-hand ultrasound for each anatomical plane and the Euclidean distances served as outcomes next to their effects on gait variables. The data suggest that regression-based methods are preferable to functional methods in this population, as the latter demonstrated the highest variability in accuracy with large errors for some individuals. INTERPRETATION: Based on our findings we recommend using the regression method presented by Hara et al. due to its superior overall accuracy of <9 mm on average in all planes and the lowest impact on kinematic and kinetic output variables. We do not recommend using the Harrington equations (single and multiple) in populations with high amounts of soft tissue as they require pelvic depth as input, which can be massively biased when a lot of soft tissue is present around the pelvis.