Impact of sagittal and coronal pelvic tilt on hip subluxation in non-ambulatory flaccid neuromuscular scoliosis patients following spinal correction.

PURPOSE: To evaluate the actual change in clinical hip pain and hip migration after operation for non-ambulatory flaccid neuromuscular (NM) scoliosis and investigate whether there is an association between hip migration and coronal/sagittal pelvic tilt (CO-PT/SA-PT). PATIENTS AND METHODS: This retrospective, single-center, observational study evaluated a total of 134 patients with non-ambulatory flaccid neuromuscular scoliosis who underwent surgery performed by a single surgeon between 2003 and 2020, with at least 2 years of follow-up period. Operation procedures were conducted in two stages, beginning with L5-S1 anterior release followed by posterior fixation. Radiologic parameters were measured at preoperative, immediate postoperative, and last follow-up periods with clinical hip pain and clinical hip dislocation events. RESULTS: The significant improvements occurred in various parameters after correction surgery for NM scoliosis, containing Cobb's angle of major curve and CO-PT. However, Reimer's hip migration percentage (RMP) was increased on both side of hip (High side, 0.23 ± 0.16 to 0.28 ± 0.21; Low side, 0.20 ± 0.14 to 0.23 ± 0.18). Hip pain and dislocation events were also increased (Visual analog scale score, 2.5 ± 2.3 to 3.6 ± 2.6, P value < 0.05; dislocation, 6-12). Logistic regression analysis of the interactions between ΔRMP(High) and the change of sagittal pelvic tilt (ΔSA-PT) after correction reveals a significant negative association. (95% CI 1.003-1.045, P value = 0.0226). CONCLUSIONS: In cases of non-ambulatory flaccid NM scoliosis, clinical hip pain, and subluxation continued to deteriorate even after correction of CO-PT. There was a relationship between the decrease in SA-PT, and an increase in hip migration percentage on high side, indicating the aggravation of hip subluxation.

Greater pelvic obliquity in adolescent idiopathic scoliosis combined with hip dysplasia.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is a spinal deformity that affects adolescents and poses a challenging public health problem. Compared to the general population, adolescents with AIS have a higher prevalence of hip dysplasia. However, the mechanisms underlying the impact of hip dysplasia on the coronal balance of the spine remain poorly understood. We hypothesized that the combination of AIS with hip dysplasia would exacerbate coronal imbalance. METHODS: We retrospectively analyzed the medical records and radiographs of adolescents diagnosed with AIS between 2015 and 2020. Participants were divided into two groups: those with hip dysplasia and those without. We recorded parameters related to the coronal deformity of the spine, sacral and pelvic obliquity, and center edge angle (CEA). We investigated differences in these parameters in those with and without hip dysplasia and analyzed their relationships in those with combined AIS and hip dysplasia. RESULTS: A total of 103 adolescents were included, 36 with hip dysplasia and 67 without. Those with hip dysplasia had significantly higher sacroiliac discrepancy (SID) compared to those without (t = - 2.438, P = 0.017). In adolescents with hip dysplasia, only iliac obliquity angle (IOA) was significantly correlated with SID (r = - 0.803, P < 0.001), with a linear relationship between them (r2 = 0.645, P < 0.001). CONCLUSIONS: The incidence of hip dysplasia is higher in the AIS population. In adolescents with combined AIS and hip dysplasia, pelvic obliquity is greater, potentially contributing to the increased prevalence of low back pain.

How Strong Is the Ligamentum Teres of the Hip? A Biomechanical Analysis.

BACKGROUND: Intraarticular hip pain represents a substantial clinical challenge, with recent studies implicating lesions in the ligamentum teres as potential contributors. Even more so, damage to the ligamentum teres is particularly prevalent among young patients undergoing joint-preserving interventions. Although several studies have investigated the biomechanical attributes of the ligamentum teres, inconsistencies in reported findings and reliance on cadaveric or animal models have raised concerns regarding the extrapolation of results to clinical practice. Furthermore, there is a lack of research examining ligamentum teres biomechanics specifically within the relevant patient cohort-individuals who benefit from joint-preserving surgical interventions. QUESTIONS/PURPOSES: We sought (1) to determine the biomechanical properties (ultimate load to failure, tensile strength, stiffness, and elastic modulus) of fresh-frozen ligaments from patients undergoing surgical hip dislocation, and (2) to identify patient-specific factors that are associated with them. METHODS: This was an institutional review board-approved study on intraoperatively harvested ligamentum teres from 74 consecutive patients undergoing surgical hip dislocation for joint preservation (August 2021 to September 2022). After the exclusion of patients with previous surgery, posttraumatic deformities, avascular necrosis, slipped capital femoral epiphysis, and Perthes disease, 31 ligaments from 31 patients were analyzed. The mean age of the study group was 27 ± 8 years, and 61% (19) of participants were male. The main indication for surgery was femoroacetabular impingement. Standardized AP pelvic and axial radiographs and CT scans were performed in all patients for better radiological description of the population and to identify associated radiological factors. The ligament was thoroughly transected at its origin on the fossa acetabuli and at the insertion area on the fovea capitis and stored at -20°C until utilization. Specimens were mounted to a materials testing machine via custom clamps that minimized slippage and the likelihood of failure at the clamp. Force-displacement and stress-strain curves were generated. Ultimate failure load (N), tensile strength (MPa), stiffness (N/mm), and elastic modulus (MPa) were determined. Using a multivariate regression analysis and a subgroup analysis, we tested demographic, degenerative, and radiographic factors as potential associated factors. RESULTS: The ligamentum teres demonstrated an ultimate load to failure of 126 ± 92 N, and the tensile strength was 1 ± 1 MPa. The ligaments exhibited a stiffness of 24 ± 15 N/mm and an elastic modulus of 7 ± 5 MPa. After controlling for potential confounding variables like age, fossa/fovea degeneration, and acetabular/femoral morphologies, we found that female sex was an independent factor for higher tensile strength, stiffness, and elastic modulus. Excessive femoral version was independently associated with lower load to failure (HR 122 [95% CI 47 to 197]) and stiffness (HR 15 [95% CI 2 to 27]). Damage to the acetabular fossa was associated with reduced load to failure (HR -93 [95% CI -159 to -27]). CONCLUSION: Overall, the ligamentum teres is a relatively weak ligament. Sex, degeneration, and excessive femoral version are influencing factors on strength of the ligamentum teres. The ligamentum teres exhibits lower strength compared with other joint-stabilizing ligaments, which calls into question its overall contribution to hip stability. CLINICAL RELEVANCE: Young patients undergoing hip-preserving surgery are the population at risk for ligamentum teres lesions. Baseline values for load to failure, tensile strength, elastic modulus, and stiffness are needed to better understand those lesions in this cohort of interest.

Musculoskeletal injections for palliative treatment of neuromuscular hip dysplasia patients: how I do it.

This review describes our institution's standardized technique as well as potential pitfalls for therapeutic steroid injections in children with symptomatic neuromuscular hip dysplasia. Symptomatic, painful neuromuscular hip dysplasia can dramatically affect quality of life. Steroid injections are used to identify the source of perceived pain, temporarily treat pain while awaiting surgical intervention, or for therapeutic management for nonoperative hip joints.

Influence of hip prosthesis position on postoperative gait in symptomatic hip osteoarthritis secondary to hip dysplasia patients after primary total hip arthroplasty: a short-term follow-up study.

BACKGROUND: The aim of this study was to analyze the influence of the positioning of the components of total hip arthroplasty (THA) evaluated by the acetabular anteversion (AA) and femoral anteversion (FA) angle on postoperative gait in patients with symptomatic hip osteoarthritis secondary to hip dysplasia undergoing THA. METHODS: Between May 2023 and May 2024, patients with symptomatic hip osteoarthritis secondary to hip dysplasia (Crowe Type I and IV) who underwent THA were enrolled in the study. The AA angle and FA angle were measured by computer tomography (CT). Gait data were determined by using the Dynamic Right Gait & Posture analysis system. The relationship between FA, AA and gait data was analyzed by Pearson correlation test, subgroup Pearson correlation test, multiple linear regression. RESULTS: A total of 40 patients (45hips) were included in the study. Compared with preoperative, the patient's postoperative foot progression angle, foot contact angle, plantarflexion velocity, swing foot speed, gait velocity, cadence, stride length were significantly improved. Preoperative FA is significantly different from postoperative FA (P < 0.05), while the difference between preoperative and postoperative AA is not significant. BMI, Crowe Type, AA were related to change of cadence. The less the postoperative AA of patients, and the more the cadence in the postoperative gait of patients. CONCLUSION: Our study showed that THA could improve the gait function of patients with symptomatic hip osteoarthritis secondary to hip dysplasia. Adjusting AA lower could obtain a much more postoperative cadence.

Application of deep learning for automated diagnosis and classification of hip dysplasia on plain radiographs.

BACKGROUND: Hip dysplasia is a condition where the acetabulum is too shallow to support the femoral head and is commonly considered a risk factor for hip osteoarthritis. The objective of this study was to develop a deep learning model to diagnose hip dysplasia from plain radiographs and classify dysplastic hips based on their severity. METHODS: We collected pelvic radiographs of 571 patients from two single-center cohorts and one multicenter cohort. The radiographs were split in half to create hip radiographs (n = 1022). One orthopaedic surgeon and one resident assessed the radiographs for hip dysplasia on either side. We used the center edge (CE) angle as the primary diagnostic criteria. Hips with a CE angle < 20°, 20° to 25°, and > 25° were labeled as dysplastic, borderline, and normal, respectively. The dysplastic hips were also classified with both Crowe and Hartofilakidis classification of dysplasia. The dataset was divided into train, validation, and test subsets using 80:10:10 split-ratio that were used to train two deep learning models to classify images into normal, borderline and (1) Crowe grade 1-4 or (2) Hartofilakidis grade 1-3. A pre-trained on Imagenet VGG16 convolutional neural network (CNN) was utilized by performing layer-wise fine-turning. RESULTS: Both models struggled with distinguishing between normal and borderline hips. However, achieved high accuracy (Model 1: 92.2% and Model 2: 83.3%) in distinguishing between normal/borderline vs. dysplastic hips. The overall accuracy of Model 1 was 68% and for Model 2 73.5%. Most misclassifications for the Crowe and Hartofilakidis classifications were +/- 1 class from the correct class. CONCLUSIONS: This pilot study shows promising results that a deep learning model distinguish between normal and dysplastic hips with high accuracy. Future research and external validation are warranted regarding the ability of deep learning models to perform complex tasks such as identifying and classifying disorders using plain radiographs. LEVEL OF EVIDENCE: Diagnostic level IV.

Insufficient stem antetorsion and lower cup abduction is a combined risk factor for posterior hip dislocation in patients undergoing THA for femoral neck fractures: a retrospective analysis.

BACKGROUND: The role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements. METHODS: We retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured. RESULTS: The study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters. CONCLUSIONS: Insufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation. LEVEL OF EVIDENCE: Prospective comparative study Level II.

Femoral head and acetabular necrosis combined with hip subluxation in people with HIV: a case report and literature review.

INTRODUCTION: HIV is widely prevalent in all regions of the world. The use of antiretroviral drugs has dramatically reduced the mortality rate of HIV-related diseases, but correspondingly increased the incidence of chronic complications in HIV-positive people. Related studies have found that the incidence of osteonecrosis of the femoral head is higher in HIV-positive people, but the co-occurrence of femoral head necrosis, acetabular necrosis and hip joint dislocation in HIV-positive patients is rare. METHODS: We report a 50-year-old man with a 15-month history of progressively worsening right hip pain with movement restriction. According to the CT findings of the other hospital, the patient was admitted to the hospital with femoral head necrosis. After the admission, the relevant X-ray, CT and MRI examinations showed that the right femoral head collapsed and deformed, with the surrounding bone sclerosis, bone fragments, loose body of the joint, right hip subluxation, acetabular marginal osteogeny, and local microcystic degeneration. The left femoral head was in good shape, and cystic degeneration can be seen under the articular surface. The patient was finally diagnosed with femoral head necrosis and acetabular necrosis combined with hip subluxation. RESULTS: The pain of the patient was significantly relieved after the operation, and the patient was discharged from the hospital one week after the start of treatment to continue rehabilitation training. During the follow-up one month after the operation, the self-reported pain disappeared completely, and the limitation of activity was significantly improved.

Hip joint rice body bursitis combined with hip dysplasia and pelvic fracture: a case report.

BACKGROUND: Rice body formation is an uncommon, nonspecific inflammatory process. Certain clinical features, such as chronic synovitis associated with rheumatoid arthritis, tuberculous arthritis, and osteoarthritis, can induce a non-specific response that may lead to the development of rice bodies. Currently, the etiological and prognostic significance of rice bodies remains unknown. Magnetic resonance imaging (MRI) is the preferred diagnostic imaging modality for evaluating rice body formation. CASE PRESENTATION: The patient, a 44-year-old female, presented with bursitis of the hip joint and the presence of numerous rice bodies. This case is exceptionally rare and unusual as it involves a combination of hip dysplasia and pelvic fracture. The patient underwent a one-stage resection of the rice body, internal fixation of the acetabular fracture, and two-stage total hip arthroplasty, resulting in an immediate improvement in her symptoms. We reviewed the relevant literature and observed that the majority of rice bodies were predominantly found within the capsules of the shoulder and knee joints, while instances of hip joint rice body bursitis were relatively infrequent. To our knowledge, there have been no previous reports documenting a case of hip joint rice body bursitis in conjunction with hip dysplasia and pelvic fracture. CONCLUSION: This paper presents the rare case of hip joint rice body bursitis combined with hip dysplasia and pelvic fracture, and is one of the highlights.

Femoro-Epiphyseal Acetabular Roof Index Values on Anteroposterior Pelvic Radiographs Significantly Increase With Hip Adduction and Decrease With Abduction.

PURPOSE: To investigate the impact of hip adduction and abduction on the femoro-epiphyseal acetabular roof (FEAR) index using conventional anteroposterior pelvic radiographs of patients with borderline hip dysplasia (BHD). METHODS: Patients with BHD (lateral center edge angle [LCEA] with values of 18° ≤ LCEA <25°) and who were subject to periacetabular osteotoym were selected from a consecutive retrospective cohort from January 2009 to January 2016. The hip ad-/abduction (adduction handled as negative values) and the FEAR index (lateral opening angles handled as positive values) were measured in the initially standardized acquired pelvic radiographs. Thereafter, using surgical planning software, different degrees of hip adduction and abduction were simulated from 20° of adduction to 30° of abduction, and the FEAR index was measured at each position. Pearson correlation was used to identify a potential correlation between the hip ad-/abduction and the FEAR index. RESULTS: Eighty-nine hips were included. Initial radiographs showed unintentional mean ad-/abduction of -5.3° ± 3.1° (range, -14° to 2°). The mean FEAR index at the initial ad-/abduction angle was -3.6° ± 7.2° (range, -18.0° to 16.0°) and was significantly different from neutral position (0° of ad-/abduction) -9.2° ± 7.0° (range, -27.0° to 10.0°) (P < .001). The FEAR index was negatively correlated to the hip ad-/abduction angle (r = 1, P < .001), with lower values for the FEAR index with the hip in abduction. CONCLUSIONS: Significant differences in FEAR index measurements were observed depending on hip ad-/abduction on pelvic radiographs. A linear change of the FEAR index of 5° per 5° of hip adduction or abduction could be demonstrated, with adduction resulting in increasing and abduction in decreasing values for the FEAR index. LEVEL OF EVIDENCE: Level III, diagnostic study.

Hip Displacement After Triradiate Closure in Ambulatory Cerebral Palsy: Who Needs Continued Surveillance?

BACKGROUND: Hip surveillance in cerebral palsy (CP) is an accepted practice with evidence-based guidelines implemented. For the skeletally immature with open triradiate cartilage (TRC), recommendations for radiographic surveillance stemmed from population-based studies. For nonambulatory CP, progression of hip displacement after skeletal maturity has been reported; less is known for ambulatory CP. We aimed to determine the prevalence and risk factors associated with progressive hip displacement after TRC closure, a proxy for skeletal maturity, for ambulatory CP. METHODS: This is a retrospective cohort study of patients with ambulatory CP (Gross Motor Function Classification System I-III), with unilateral or bilateral involvement, hypertonic motor type, regular hip surveillance (≥3 radiographs after age 10 yr, 1 before TRC closure, ≥1 after age 16 yr), and 2-year follow-up post-TRC closure. The primary outcome was migration percentage (MP). Other variables included previous preventative/reconstructive surgery, topographic pattern, sex, scoliosis, epilepsy, and ventriculoperitoneal shunt. An "unsuccessful hip" was defined by MP ≥30%, MP progression ≥10%, and/or requiring reconstructive surgery after TRC closure. Statistical analyses included chi-square and multivariate Cox regression. Kaplan-Meier survivorship curves were also determined. Receiver operating characteristic analysis was used to determine the MP threshold for progression to an "unsuccessful hip" after TRC closure. RESULTS: Seventy-six patients (39.5% female) met the inclusion criteria, mean follow-up 4.7±2.1 years after TRC closure. Sixteen (21.1%) patients had an unsuccessful hip outcome. By chi-square analysis, diplegia ( P =0.002) and epilepsy ( P =0.04) were risk factors for an unsuccessful hip. By multivariate analysis, only first MP after TRC closure ( P <0.001) was a significant risk factor for progression to an unsuccessful hip; MP ≥28% being the determined threshold (receiver operating characteristic curve analysis, area under curve: 0.845, P <0.02). CONCLUSIONS: The risk of MP progression after skeletal maturity is relatively high (21%), similar to nonambulatory CP. Annual hip surveillance radiographs after TRC closure should continue for Gross Motor Function Classification System I-III with an MP ≥28% after TRC closure, especially for bilateral CP and epilepsy. LEVEL OF EVIDENCE: III.

How Reliable Is the Measurement of the Lateral Center Edge Angle on Scoliosis Radiographs for Detecting Acetabular Dysplasia?

PURPOSE: Hip dysplasia reportedly occurs in up to 12% of the general population and may be higher in patients with adolescent idiopathic scoliosis (AIS). When using lateral center edge angle (LCEA) measurements to help identify hip dysplasia, it is uncertain if this measurement can be performed reliably on scoliosis radiographs due to parallax. The purpose of this study is to evaluate the reliability of measuring LCEA on scoliosis radiographs compared with standard pelvis radiographs. METHODS: This study evaluated 40 hips on 20 patients (mean age 12.5 years ± 3.1; 50% Female) who received PA scoliosis radiographs and AP pelvis radiographs within 1 year of each other. Review was performed by 4 pediatric radiologists (2 general, 2 MSK), 2 pediatric orthopaedic surgeons, and 1 research fellow. Radiographic measurement of the LCEA for each hip was first performed on the scoliosis radiograph. After a minimum of 3 days, the LCEA was measured on a pelvis radiograph of the same individual obtained within 1 year of the scoliosis radiograph. Pearson coefficient was used to measure agreement between scoliosis and pelvis radiograph measurements. Intraclass correlation coefficient (ICC) was used to evaluate intraobserver and interobserver agreement. ICC values <0.5 were classified as poor reliability, 0.5 to 0.75 were classified moderate, 0.75 to 0.90 were classified good, and >0.9 indicated excellent reliability. RESULTS: The mean difference between scoliosis and pelvis radiographs was 54 ± 79 days. There was good-to-excellent interobserver agreement on LCEA measurements made between readers on scoliosis radiographs (ICC: 0.94, 95% CI: 0.90-0.96, P <0.001) and pelvis radiographs (ICC: 0.91, 95% CI: 0.83-0.95, P <0.001), and moderate-to-excellent intraobserver agreement for scoliosis radiographs (ICC range: 0.68 to 0.98; P <0.001) and pelvis radiographs (ICC range: 0.62 to 0.96; P <0.001). There was a strong correlation between LCEA measurements made on scoliosis and pelvis radiographs ( r2 =0.66, P <0.001), and the intermodality agreement between scoliosis and pelvis radiograph LCEA measurements were moderate to good (ICC range: 0.68 to 0.89, P <0.001). CONCLUSIONS: Overall, there was good-to-excellent agreement between readers on scoliosis and pelvis radiographs, respectively, and moderate-to-excellent intraobserver agreement between LCEA measurements made on scoliosis radiographs and pelvis radiographs, respectively. LCEA measurements made on scoliosis radiographs strongly correlated to the measurements made on pelvis radiographs, and the intermodality ICC was also considered moderate to good. Dedicated pelvis radiographs may not be necessary during scoliosis workup and follow-up surveillance, thereby decreasing radiation exposure, cost, and improving patient care workflow. LEVEL OF EVIDENCE: Level IV-diagnostic study.

The Prevalence of Hip Dysplasia on Radiographs for Adolescent Idiopathic Scoliosis.

BACKGROUND: During radiographic assessment of adolescent idiopathic scoliosis (AIS), upright images frequently capture the hip. The purpose of this study was to assess the prevalence of radiographic hip dysplasia on postero-anterior (PA) scoliosis radiographs, as defined as a lateral center edge angle (LCEA) ≤25 degrees. METHODS: All patients with upright PA scoliosis radiographs over a one-year study period at a single tertiary academic medical center (2020 to 2021) were included in the study. Radiographs containing the hip joints were annotated by 3 reviewers for left and right LCEA, and triradiate cartilage (TRC) status. Inter-rater reliability was determined among the 3 reviewers. RESULTS: Two hundred fifty patients {500 hips, 75.6% female, median age 14 [interquartile range (IQR)=3]} had PA scoliosis radiographs that captured the hip, which qualified for analysis. Seventy-four hips (14.8%) demonstrated evidence of dysplasia (LCEA ≤25 deg) in 55/250 patients (22%). The median LCEA was significantly lower in the dysplastic hip cohort (23.9 deg, IQR=4.8 deg), compared with those without dysplasia (33 deg IQR=7.3 deg; P =0.001). A higher percentage of dysplastic hip patients were female than male (72.7% vs. 27.3%). Patients with bilateral dysplasia had a similar LCEA ( 22.9 deg) [to those with unilateral dysplasia (22.9 deg left, 23.9 deg right, P =0.689)]. CONCLUSIONS: In a cohort of 250 AIS patients, 22% demonstrated evidence of hip dysplasia, as defined as an LCEA ≤2 degrees. The dysplastic patients were more likely to be female. Screening for hip symptomatology in AIS patients may be of benefit, considering the frequency of radiographic hip dysplasia in this population. LEVEL OF EVIDENCE: III. Type of Evidence: diagnostic.

What Do We Really Know About the Natural History of Spastic Hip Dysplasia and Pain in Total-involvement Cerebral Palsy? A Systematic Review.

BACKGROUND: Hip surveillance protocols and surgery for spastic hip dysplasia have become standard of care for children with cerebral palsy (CP) out of concern for long-term sequelae, including pain. It is unclear if available data support that spastic hip dysplasia/dislocation independently correlates with pain in total-involvement CP. A better understanding of this correlation may help guide decision-making for these medically complex patients. METHODS: We undertook a systematic literature review to assess published data on the association of spastic hip dysplasia and pain in total-involvement CP using PubMed (which includes the MedLine databases) and EMBASE databases. A total of 114 English-language articles were identified. Fifteen articles met the inclusion criteria and were evaluated using the PRISMA guidelines for systematic reviews. RESULTS: Of 15 articles that specifically assessed the association of spastic hip dysplasia and pain, 5 articles provided strong evidence per our criteria regarding the correlation of pain and spastic hip dysplasia. All 5 articles described the severity of CP in their studied population, radiographically defined hip displacement, included a control group, and described how pain was assessed. Nevertheless, there was no standard classification of dysplasia between studies and the ages of patients and methods of pain determination varied. Four of the articles provided level III evidence and one provided level II evidence. Of these 5 articles with the strongest available evidence, data from 2 did not support a correlation between hip dysplasia and hip pain, 2 supported a correlation, and 1 was equivocal. CONCLUSIONS: Even the best available evidence on spastic hip dysplasia and pain reveals no consensus or conclusion on whether spastic hip dysplasia and dislocation in total-involvement CP is independently correlated with pain. LEVEL OF EVIDENCE: Level III-Prognostic study.

Acetabular "Fleck" Sign: Outcomes of Surgical Repair.

BACKGROUND: Traumatic, posterior hip dislocations in the pediatric population are typically managed by closed reduction to achieve a concentric hip joint. The presence of an acetabular "fleck" sign, despite concentric reduction, has been shown to signify significant hip pathology. The purpose of this study was to evaluate the outcomes of open labral repair through a surgical hip dislocation (SHD) in a consecutive series of patients with an acetabular "fleck" sign associated with a traumatic hip dislocation/subluxation. METHODS: A retrospective review of patients between 2008 and 2022 who presented to a single, level 1 pediatric trauma center with a traumatic posterior hip dislocation/subluxation was performed. Patients were included if they had an acetabular "fleck" sign on advanced imaging and underwent open labral repair through SHD. Medical records were reviewed for sex, age, laterality, mechanism of injury (MOI), and associated orthopaedic injuries. The modified Harris hip score (mHHS) was utilized as the primary clinical outcomes measure. Patients were assessed for the presence of heterotopic ossification (HO) and complications, including implant issues, infection, avascular necrosis (AVN), and post-traumatic dysplasia. RESULTS: Twenty-nine patients (23 male, average age: 13.0±2.7 y; range: 5.2 to 17.3) were identified. Eighteen injuries were sports related, 9 caused by motor vehicle accidents, and 1 pedestrian struck. All patients were found to have an acetabular "fleck" sign on CT (26 patients) or MRI (5 patients). Associated injuries included: femoral head fracture (n=6), pelvic ring injury (n=3), ipsilateral femur fracture (n=2), and ipsilateral PCL avulsion (n=1). At the latest follow-up (2.2±1.4 y), all patients had returned to preinjury activity/sport. Three patients developed asymptomatic, grade 1 HO in the greater trochanter region. There was no incidence of AVN. One patient developed post-traumatic acetabular dysplasia due to early triradiate closure. mHHS scores showed excellent outcomes (n=21, 94.9±7.4, range: 81 to 100.1). CONCLUSIONS: The acetabular "fleck" sign indicates a consistent pattern of osteochondral avulsion of the posterior/superior labrum. Restoring native hip anatomy and stability is likely to improve outcomes. SHD with open labral repair in these patients produces excellent clinical outcomes, with no reported cases of AVN. LEVEL OF EVIDENCE: Level IV-therapeutic.

Twelve to Twenty-year Follow-up of Dega Acetabuloplasty in Patients With Developmental Dysplasia of the Hip: Is it as Effective as Expected?

BACKGROUND: Although Dega acetabuloplasty is widely used for the treatment of developmental dysplasia of the hip, there is a paucity of data on long-term outcomes. The purpose of the study was to evaluate the rate of residual acetabular dysplasia after Dega acetabuloplasty. METHODS: Patients of a previously reported consecutive series of 35 patients (43 hips) operated by a single surgeon were recontacted for long-term follow-up. Of these, 25 patients (32 hips) consented, with a follow-up rate of 71% (74% of hips). The mean age at the time of surgery was 35 (18 to 65) months. The presence of residual dysplasia was noted according to the lateral center-edge angle of Wiberg, femoral head extrusion index, and Tönnis angle. The latest radiographic outcome was evaluated according to the Severin classification and patients were clinically evaluated according to the modified McKay criteria. RESULTS: The mean follow-up duration of 16.5 (12 to 20) years yielded an average age of 19.2 (14 to 23) years at the time of analysis. According to lateral center-edge angle, femoral head extrusion index, and Tönnis angle, 5 (15.6%) hips were dysplastic and 2 (6.3%) hips were reoperated for resubluxation. Thus, a total of 7 hips (21.9%) were considered to have residual dysplasia. With the exception of 2 hips that underwent further osteotomies, no other hips were re-subluxated or redislocated. Overcoverage was noted in 6 (18.7%) hips. There were 26 Severin group I and II (81.3%), 4 Severin group III (12.5%), and 2 Severin group IV (6.2%) hips. According to modified McKay criteria, 20 (62.5%) hips were excellent, 7 (21.9%) hips were good, and 5 (15.6%) were fair. Severin classification and modified McKay criteria were correlated with dysplasia ( P < 0.05). CONCLUSIONS: Seventy-eight percent of the hips treated by Dega acetabuloplasty for developmental dysplasia of the hip did not have acetabular dysplasia at a mean follow-up of 16 years. Even in well-treated asymptomatic hips, patients should be followed regularly, especially for residual dysplasia. LEVEL OF EVIDENCE: Level IV.

How useful are indirect radiographic measurements of hip instability in borderline hip dysplasia? An MRI-based comparison to a healthy cohort.

PURPOSE: Symptomatic hips with borderline hip dysplasia (BHD) morphology pose a challenge in differentiating stable from unstable hips. The current study aims to compare indirect radiographic signs of instability in a symptomatic BHD population to those in a healthy cohort. METHODS: The study group consisted of patients with a lateral centre-edge angle (LCEA) with values 18° ≤ LCEA < 25° who underwent corrective periacetabular osteotomy (PAO) and reported an improvement in patient-reported outcome measures (PROMs). The comparison group consisted of a healthy cohort of athletes who did not complain of any hip-related symptoms and who had normal values of their hip morphological parameters (LCEA, acetabular index (AI°), alpha angle (α°), femoral version, acetabular version). Indirect signs of instability consisting of the femoro-epiphyseal acetabular roof index (FEAR), iliocapsularis-to-rectus-femoris (IC/RF) ratio and labral dimensions (height-to-length ratio) were assessed in both groups. Partial Pearson correlation, logistic multiple regression analysis and Receiver-Operating Characteristic (ROC) curve analysis were performed to determine correlations, as well as the sensitivity and specificity of these signs to differentiate between healthy hips and BHD. RESULTS: On binary logistic multiple regression analysis, the FEAR Index was the only independent predictor to differentiate between BHD and healthy hips (p < 0.001). The IC/RF ratio did not achieve significance. The calculated area under the curve (AUC) was 0.93 (0.87 - 0.99, CI 95%, p < 0.001) for the FEAR Index and 0.81 (0.70 - 0.92, CI 95%, p < 0.001) for the height-length ratio. Using the predefined cut-off values (dysplastic-FEAR Index ≥ 5° or labral height-to-length ratio ≤ 0.5), 27% sensitivity/100% specificity and 20% sensitivity/ 100% specificity, were achieved. ROC analysis provided the following new thresholds: FEAR Index ≥ -5° (73% sensitivity/97% specificity); labral height-to-length ratio ≤ 0.8 (70% sensitivity, 79% specificity). CONCLUSION: In our cohort, the FEAR index was an independent parameter that could differentiate between borderline dysplastic and asymptomatic hips. The previously published values for both the FEAR index and labral hypertrophy ratio had a poor sensitivity in differentiating symptomatic unstable BHD from healthy hips. The cut-off values of ≥ -5° (FEAR index) and ≤ 0.8 (labral height-to-length ratio) provided acceptable sensitivity and specificity when comparing to morphological healthy hips.

The role of different acetabular morphologies on patient-reported outcomes following periacetabular osteotomy in borderline hip dysplasia.

INTRODUCTION: The treatment option for borderline hip dysplasia (BHD) includes hip arthroscopy and periacetabular osteotomy (PAO). To the present day the controversial discussion remains, which intervention to prefer. Literature reports supporting an educated choice are scare, based on small patient cohorts and do not address the variability of acetabular morphology. Consequently, we intended to report PAO outcomes, from patients diagnosed with BHD, dependent on acetabular morphology, in a large patient cohort and aimed to define risk factors for poor clinical results and patient satisfaction. MATERIALS AND METHODS: A prospective monocentre study was conducted. Patients enrolled underwent PAO for symptomatic BHD (LCEA, 18°-25°). A total of 107 hips were included with 94 complete data sets were available for evaluation with a minimum follow-up of 1 year and a mean follow-up of 2.3 years. The mean age was 31 ± 8.2 years, and 81.3% were female. As the primary outcome measure, we utilized the modified Harris hip score (mHHS) with minimal clinically important change (MCID) of eight to define clinical failure. Results were compared after a comprehensive radiographic assessment distinguishing between lateral deficient vs. anterior/posterolateral deficient acetabular and stable vs. unstable hip joints. RESULTS: Overall, clinical success was achieved in 91.5% of patients and the mHHS improved significantly (52 vs. 84.7, p < 0.001). Eight hips failed to achieve the MCID and four had radiographic signs of overcorrection. Comparing variable joint morphologies, the rate of clinical success was higher in patients with an anterior/posterolateral deficient acetabular covarage compared to lateral deficient acetabular (95.2% vs. 90.4%). tThe highest rate of clinical failure was recorded in unstable hip joints (85.7% vs. 92.5% in stable hips). CONCLUSIONS: This study demonstrates that PAO is an effective means to treat symptomatic BHD with variable acetabular morphologies, achieving a clinical success in 91.5% of all patients. To maintain a high level of safety and patient satisfaction technical accuracy appears crucial.

Mobility of the lumbo-pelvic-hip complex (spinopelvic mobility) and sagittal spinal alignment - implications for surgeons performing hip arthroplasty.

INTRODUCTION: The optimal positioning of the hip prosthesis components is influenced by the mobility and balance of the spine. The present study classifies patients with pathology of the spino-pelvic-hip complex, showing possible methods of preventing hip dislocations after arthroplasty. HYPOTHESIS: Hip-Spine Classification helps arthroplasty surgeons to implant components in more patient-specific position. MATERIALS AND METHODS: The group of 100 patients treated with total hip arthroplasty. Antero-posterior (AP) X-rays of the pelvis in a standing position, lateral spine (standing and sitting) and AP of the pelvis (supine after the procedure) were analyzed. We analyzed a change in sacral tilt value when changing from standing to sitting (∆SS), Pelvic Incidence (PI), Lumbar Lordosis (LL) Mismatch, sagittal lumbar pelvic balance (standing position). Patients were classified according to the Hip-Spine Classification. Postoperatively, the inclination and anteversion of the implanted acetabular component were measured. RESULTS: In our study 1 A was diagnosed in 61% of all cases, 1B in 18%, 2 A in 16%, 2B in 5%. 50 out of 61 (82%) in group 1 A were placed within the Levinnek "safe zone". In 1B, 2 A, 2B, the position of the acetabular component was influenced by both the spinopelvic mobility and sagittal spinal balance. The mean inclination was 43.35° and the anteversion was 17.4°. CONCLUSIONS: Categorizing patients according to Hip-Spine Classification one can identify possible consequences the patients at risk. Pathology of the spino-pelvic-hipcomplex can lead to destabilization or dislocation of hip after surgery even though implanted according to Lewinnek's indications. Our findings suggest that Lewinnek safe zone should be abandoned in favor of the concept of functional safe zones.

Comparison of the distraction index and Norberg angle with radiographic grading of canine hip dysplasia.

The Orthopedic Foundation for Animals (OFA) radiographic grading system stands as a well-established benchmark for categorizing hip dysplasia in canines. Although more objective techniques to quantify early hip laxity in young dogs, such as the Norberg angle (NA) and distraction index (DI), have been documented, there is a scarcity of published studies that directly compare these radiographic measures. The primary objectives of this prospective, analytical study were to assess and compare the NA and DI measures with OFA grades within a cohort of dogs. Thirty dogs (57 hip joints) were evaluated, with a mean age of 5.4 ± 2.9 years and a mean body weight of 34.3 ± 7.1 kg. The discriminative power of hip dysplasia for DI and NA used OFA as a reference were compared by multivariate discriminant analysis test. Using the DI (≤0.3) 12 joints were classified as normal, using NA (≥105°) 24 joints and using OFA (≤3) 29. When comparing the discriminant power of NA with OFA resulting similar (P = .8324) with correct classifications of 81% using cross validation, however, the discriminant power of dysplasia of the DI resulted significantly greater (P = .0034) than OFA with correct classifications of only 59% using cross-validation, consequently it was possible determined that of 29 patients with OFA ≤ 3, 20 had DI > 0.3. These findings demonstrated that phenotypic healthy dogs according to OFA grading can present passive hip joint laxity, as demonstrated by radiographic evaluation with distraction. Furthermore, DI can contribute to the screening of CHD when evaluated in conjunction with OFA grading.