Combined Irreducible Femoral Head Fracture-Dislocation and Ipsilateral Segmental Femur Fracture: A Case Report.

CASE: A 48-year-old man presented to a Level 1 trauma center after a motor vehicle crash with a right irreducible posterior hip dislocation and ipsilateral fractures of the femoral head and segmental femur shaft. This injury was managed with open reduction and internal fixation and antegrade intramedullary nailing. CONCLUSION: This is the first report of a combined irreducible femoral head fracture-dislocation and a segmental femur fracture, a rare injury that requires a stepwise approach to operative management of each injury. Surgeons must recognize the clinical and radiographic findings associated with irreducible hip dislocations in the setting of ipsilateral fractures to the femoral head and shaft.

Imaging Modalities in the Preoperative Assessment of Femoroacetabular Impingement and Hip Dysplasia: Determining Best Practices.

¼ In the last decade, significant progress has been made in understanding hip pain, especially related to femoroacetabular impingement (FAI) and hip dysplasia (HD), which collectively affect over 20% of the population.¼ Preoperative imaging, including plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US), plays a pivotal role in diagnosing FAI and HD. Imaging precision, standardized techniques, and accurate interpretation are crucial for effective treatment planning.¼ The continual advancements in imaging techniques, especially seen in MRI (arthrograms, application of leg traction, and delayed gadolinium-enhanced MRI of cartilage), represent important strides in the precise assessment of pathology associated with FAI and HD.¼ By incorporating these advancements into routine imaging protocols, healthcare providers can ensure a comprehensive understanding of hip joint dynamics, enabling more accurate diagnosis and effective management strategies for patients with FAI and HD, ultimately leading to improved clinical outcomes.

Asymmetric fracture dislocation of the hips: case report.

Bilateral asymmetric hip fracture dislocation is an extremely rare entity. The injury is caused by a high velocity mechanism. We reported a case of bilateral hip fracture dislocation and its management. A 30-year-old man with no previous medical or surgical history was involved in a road accident involving a high-speed collision between two trucks. X-rays of the pelvis revealed asymmetrical bilateral fracture-luxation of the hips. The reduction of the hips was done under general anesthesia. Asymmetrical bilateral traumatic dislocation fracture of the hip is a rare serious injury. Reduction must be performed within 6 hours. Short- and long-term monitoring of the patient is essential.

Surgical hip dislocation technique through the femoral head fovea fenestration and impaction bone grafting for the treatment of non-traumatic osteonecrosis of the femoral head: a retrospective study.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) often leads to the collapse of the femoral head, ultimately resulting in patients undergoing premature total hip arthroplasty (THA). The surgical hip dislocation (SHD) technique is a type of hip-preserving surgery aimed at delaying or avoiding THA. This study aims to evaluate the clinical efficacy of SHD techniques through femoral head fovea fenestration and impaction bone grafting for the treatment of non-traumatic ONFH. METHODS: A retrospective analysis was conducted on the clinical data of 39 patients (39 hips) with non-traumatic ONFH who underwent SHD for treatment from 2016 to 2017. The Harris hip score (HHS) and the minimum clinically important difference (MCID) are used to evaluate clinical outcomes, while radiographic evaluations are conducted using X-rays. Kaplan-Meier survival analysis defined clinical failure as further THA, and conducted univariate survival analysis and Cox regression analysis. Any complications were recorded. RESULTS: All patients were followed up for 24-72 months, with an average of (60 ± 13.0) months. At the last follow-up, based on the HHS, 25 patients (64.1%) reported excellent and good clinical outcomes. 29 patients (74.3%) achieved MCID. Imaging evaluation of the postoperative femoral head status showed that 6 cases improved, 20 cases remained stable, and 13 cases showed progressed. Out of 39 hips, 12 hips had postoperative clinical failure, resulting in a clinical success rate of 69.2%. Association Research Circulation Osseous (ARCO) stage, China-Japan Friendship Hospital (CJFH) classification, and postoperative crutch-bearing time are risk factors for clinical failure. Postoperative crutch-bearing time of less than 3 months is an independent risk factor for clinical failure. After surgery, there was one case of sciatic nerve injury and one case of heterotopic ossification. There were no infections or non-union of the greater trochanter osteotomy. CONCLUSION: The SHD technique through the femoral head fovea fenestration and impaction bone grafting provides a safe and effective method for treating non-traumatic ONFH, with good mid-term clinical outcomes. ARCO staging, CJFH classification, and postoperative crutch-bearing time are risk factors that affect clinical outcomes after surgery and lead to further THA. Insufficient postoperative crutch-bearing time is an independent risk factor for clinical failure.

Factors associated with joint survival after transposition osteotomy of the acetabulum in patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia.

Aims: The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia. Methods: We reviewed patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia who underwent TOA between November 1998 and December 2019. Patient demographic details, osteotomy-related complications, and the modified Harris Hip Score (mHHS) were obtained via medical notes review. Radiological indicators of hip dysplasia were assessed using preoperative and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors of failure. Results: This study included 127 patients (137 hips). Median follow-up period was ten years (IQR 6 to 15). The median mHHS improved from 59 (IQR 52 to 70) preoperatively to 90 (IQR 73 to 96) at the latest follow-up (p < 0.001). The survival rate was 90% (95% CI 82 to 95) at ten years, decreasing to 21% (95% CI 7 to 48) at 20 years. Fair joint congruity on preoperative hip abduction radiographs and a decreased postoperative anterior wall index (AWI) were identified as independent risk factors for failure. The survival rate for the 42 hips with good preoperative joint congruity and a postoperative AWI ≥ 0.30 was 100% at ten years, and remained at 83% (95% CI 38 to 98) at 20 years. Conclusion: Although the overall clinical outcomes of TOA in patients with advanced osteoarthritis are suboptimal, favourable results can be achieved in selected cases with good preoperative joint congruity and adequate postoperative anterior acetabular coverage.

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.

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.

Comparison of SHD-IBG and PVIBGT in ONFH including mechanical and pathological analysis of failure cases.

Currently, there is a lack of relevant research on the efficacy difference between SHD combined with IBG and PVIBGT in the treatment of osteonecrosis of the femoral head(ONFH). Firstly, this study intends to compare the effectiveness of surgical hip dislocation combined with impacting bone grafts (SHD-IBG) and pedicled vascularised iliac bone graft transfer (PVIBGT) in treating ONFH. And the study investigates patients who suffered from hip preservation failures from both groups to better comprehend failure reasons. 30 patients (34 hips) with ARCO stage IIIA femoral head necrosis were selected between January 2012 and July 2022. They were divided into group A(SHD-IBG) and group B (PVIBGT) according to different surgical methods. Firstly, compared the 1-year effect between SHD-IBG and PVIBGT at 1 year postoperatively; Secondly, assessed the medium and long-term efficacy of SHD-IBG hip preservation treatment; Lastly, based on study of the femoral head removed from patients with hip preservation failure in the two groups, the reasons for the failure of hip preservation were comprehensively analyzed in the two groups. Group A: 11 males (13 hips), 4 females (4 hips);Group B: 9 males (11 hips), 6 females (6 hips).Firstly, the average Harris scores of the two groups at 1 year after surgery: preoperative: 70.7, 1 year after surgery: 78.9 in group A; preoperative: 69.5, 1 year after surgery: 81.5 in group B. The differences were statistically significant (P < 0.05).Compared to the preoperative period, quantitative analysis by DCE-MRI showed an increase in perfusion in the necroticarea and an improvement in hyperperfusion in the repair-responsive area one year after the surgery. Secondly, in group A, the hip preservation rate was 88.2% at 2.5-11 (average of 77 months) years of follow-up, and the mean Harris score at the last follow-up was 73.2.Semi-quantitative analysis of postoperative DCE-MRI showed that the perfusion curves of necrotic and repaired areas were similar to those of the normal area. This suggests the instability within the femoral head had been effectively improved, and the perfusion had partially recovered. Thirdly, according to Micro-CT and pathologica studies of patients with hip preservation failure in these two groups, all these patients' femoral head was significantly collapsed and deformed. Their trabeculae was thin and partially disorganized, with fractures in the subchondral bone and separation of the cartilage from the subchondral bone. The necrotic areas had sparse trabeculae, disorganized arrangement, loss of continuity, and disappearance of cells in the trabecular traps. The necrotic area was covered with fibrous tissue, and partial restoration was observed in the repair area. Mechanical finite element analysis showed that the maximum equivalent force was observed in the weight- bearing area and the cortical bone surrounding the shaft of femurand. The result of DCE-MRI showed that the repair reaction area exhibited abnormal hyperperfusion. In this study, the efficacy of SHD-IBG and PVIBGT was compared at 1 year after operation, and the long-term follow-up of SHD-IBG was 2.5-11 (mean 77 months) years, combined with DCE-MRI results, we found that the short-term effect of PVIBGT was more significant than that of SHD-IBG. SHD-IBG can achieve satisfactory hip preservation in the medium and long term follow-up.

Predictive Factors for Intraoperative Determination for the Need of Femoral Osteochondroplasty After Periacetabular Osteotomy for Acetabular Dysplasia.

Background: Determination of need for osteochondroplasty (OCP) during periacetabular osteotomy (PAO) commonly relies on intraoperative assessment of internal rotation at 90° flexion (IRF). Performing an OCP helps decrease the risk of iatrogenic femoroacetabular impingement from PAO reduction. Avoiding impingement helps decrease risks of accelerated secondary osteoarthritis. The literature is limited for factors that predict need for OCPs during PAOs. The purpose of this study was to (1) define the characteristics of patients needing concurrent OCP and provide OCP rate based on IRF and femoral version and (2) identify predictive factors (clinical, radiographic) associated with need for OCP during PAO. As some surgeons determine need for OCP pre-operatively, predictive factors would aid decision making. Methods: This was a prospective cohort of 224 hips (207 patients) who underwent PAO for symptomatic acetabular dysplasia, of which 154 hips (69%) underwent OCP between years 2013 and 2017. Patients underwent OCP if they had restrictions in motion or impingement intra-operatively. Pre-operative factors such as age, sex, BMI, and CT findings were recorded that underwent univariate and multivariable analyses. Multivariable analysis found predictors that were described using odds ratios and 95% confidence intervals. IRF>30° and femoral version 10°-25° were used as the reference groups during categorical analysis. P-values ≤0.05 were considered significant. Results: Alpha angles >55° (OR= 2.20, CI: 1.08-4.52, p= 0.03), IRF≤20° (OR: 9.52, CI: 3.87-23.40, p<0.001), IRF >20°-30° (OR: 2.68, CI: 1.08-6.62, p=0.03), and femoral version <10° (OR: 5.26, CI: 1.09-25.30, p=0.04) were associated with increased odds of OCP. On continuous modeling, decreasing femoral version (OR: 1.07, CI: 1.02-1.12, p=0.002) and IRF (OR: 1.06, CI: 1.03-1.09, p<0.001) were associated with increased chance of OCP. For 5° changes, the chance of OCP increased by 40% (OR: 1.40, CI: 1.13-1.73, p=0.002) and 35% (OR: 1.35, IC: 1.16-1.57, p<0.001), respectively. Conclusion: Awareness of need for OCP may be valuable in peri-operative planning for these patients especially since some surgeons perform this technique arthroscopically before PAO. Factors associated with increased chances of OCP were alpha angles >55°, decreased IRF, and decreased femoral version. More studies in the future would help determine how OCP affects patient outcomes. Level of Evidence: III.

Prevalence of Radiographic Hip Dysplasia in the General Adult Population: A Systematic Review.

Background: Acetabular dysplasia has a wide range of prevalence reported in the literature. This variation is likely due to differences in the population under investigation and studies focusing on cohorts with hip pain and osteoarthritis. There are reports of radiographic hip dysplasia prevalence for adults without hip pain but there is no systematic review of these studies to document the incidence in the general population. The purpose of this systematic review was to provide a full summary of all studies that report prevalence of hip dysplasia in adults without hip pain. Methods: PRISMA guidelines were utilized as an outline for this systematic review. Articles were pulled from PubMed, OVID Medline, Embase, SCOPUS, Cochrane Central Register of Clinical Trials, and clinicaltrials.gov from their inception dates to 1/7/24. Studies were included if participants were asymptomatic and reported rates of prevalence. Results: Fourteen studies were included in this systematic review. There were 10,998 hips from 5,506 participants included in this analysis. The overall prevalence of radiographic hip dysplasia was 2.3%. Eight studies of 5,930 hips reported the prevalence of hip dysplasia by sex. The prevalence rate in these studies was 3.8% in females and 2.7% in males. Conclusion: Acetabular dysplasia based on radiographic measurements is relatively common in the general adult population. Furthermore, females have a higher prevalence rate when compared to males. It is important to recognize the incidence of hip dysplasia in the asymptomatic adult population as we recommend surgical treatment for patients who present with hip pain and dysplasia. Further studies should investigate the natural history of untreated and treated hip dysplasia. Level of Evidence: III.

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.

Acetabular dysplasia and posterior wall fractures: The missing link?

BACKGROUND: Traumatologists are unable to predict hip instability based on CT scans and standard radiographs in posterior wall (PW) fractures comprising <50-60 % of the wall, necessitating an examination under anesthesia (EUA). Risk factors for instability have not been clarified, but acetabular dysplasia has been theorized as a potential etiology. Unfortunately, dysplasia is difficult to evaluate in the traumatic setting. The purpose of this study was to compare acetabular morphology between unstable and stable fractures with a novel method to detect dysplasia. METHODS: Patients ≥ 18 years old with a PW fracture that underwent an EUA from 2013 to 2023 were retrospectively identified. For our experimental measurements, the axial distances on CT between the acetabular dome, lateral acetabular opening, and femoral head vertex were recorded. Acetabular geometry was quantified at these levels. Conventional dysplasia metrics (e.g., Tonnis angle) were obtained. Variables were compared between stable and unstable fractures. RESULTS: 58 patients met inclusion criteria with 42 stable versus 16 unstable fractures. Unstable fractures had higher distances between the acetabular dome and femoral head vertex (p > 0.05). They had more cranial fracture exit points (p = 0.0015), lower femoral head coverage (p = 0.0102), and lower posterior acetabular sector angles (p = 0.0281). No other differences in acetabular geometry, demographics, injury characteristics, or other markers of dysplasia were identified. CONCLUSIONS: Unstable hips demonstrated a more recessed acetabular dome when compared to stable hips. Posterior acetabular femoral head coverage and cranial fracture exit point may be related to hip instability. A larger sample size is needed to validate these findings.

Use of the flat panel detector fluoroscope reduces radiation exposure during periacetabular osteotomy.

The Periacetabular Osteotomy is a technically demanding procedure that requires precise intraoperative evaluation of pelvic anatomy. Fluoroscopic images pose a radiation risk to operating room staff, scrubbed personnel, and the patient. Most commonly, a Standard Fluoroscope with an Image Intensifier is used. Our institution recently implemented the novel Fluoroscope with a Flat Panel Detector. The purpose of this study was to compare radiation dosage and accuracy between the two fluoroscopes. A retrospective review of a consecutive series of patients who underwent Periacetabular Osteotomy for symptomatic hip dysplasia was completed. The total radiation exposure dose (mGy) was recorded and compared for each case from the standard fluoroscope (n = 27) and the flat panel detector (n = 26) cohorts. Lateral center edge angle was measured and compared intraoperatively and at the six-week postoperative visit. A total of 53 patients (96% female) with a mean age and BMI of 17.84 (± 6.84) years and 22.66 (± 4.49) kg/m2 (standard fluoroscope) and 18.23 (± 4.21) years and 21.99 (± 4.00) kg/m2 (flat panel detector) were included. The standard fluoroscope averaged total radiation exposure to be 410.61(± 193.02) mGy, while the flat panel detector averaged 91.12 (± 49.64) mGy (p < 0.0001). The average difference (bias) between intraoperative and 6-week postoperative lateral center edge angle measurement was 0.36° (limits of agreement: - 3.19 to 2.47°) for the standard fluoroscope and 0.27° (limits of agreement: - 2.05 to 2.59°) for the flat panel detector cohort. Use of fluoroscopy with flat panel detector technology decreased the total radiation dose exposure intraoperatively and produced an equivalent assessment of intraoperative lateral center edge angle. Decreasing radiation exposure to young patients is imperative to reduce the risk of future comorbidities.

Femoroacetabular Variations Are Predisposing Factors for Traumatic Posterior Hip Dislocation.

BACKGROUND: Although high-energy trauma mechanisms are generally considered to cause traumatic posterior hip dislocations, femoroacetabular variations are assumed to contribute to low-impact hip dislocations. Thus, the present study aimed to identify morphologic femoral and acetabular risk factors that may also contribute to posterior hip dislocations in high-energy trauma mechanisms. METHODS: The acetabular and femoral morphology of 83 hips with a traumatic posterior dislocation following a high-energy trauma mechanism were analyzed and matched to a control group of 83 patients who sustained high-energy trauma without a hip injury. The lateral center-edge angle, acetabular index, acetabular depth/width ratio, cranial and central acetabular version angles, and the anterior and posterior acetabular sector angles were measured on computed tomography to quantify femoroacetabular impingement (FAI) morphology, acetabular version, and coverage. The caput-collum-diaphyseal angle and the alpha angles in the coronal and axial planes were measured to detect cam-type FAI deformity. A receiver operating characteristic curve was utilized to determine threshold values for an increased risk of hip dislocation. RESULTS: Acetabular retroversion and posterior acetabular undercoverage were significantly increased in patients with hip dislocations compared with controls (p < 0.001). The central acetabular version angle and posterior acetabular sector angle that indicated an increased risk of hip dislocation were ≤9° and ≤90°, respectively. Cam-type FAI deformity and coxa valga were significantly increased in the dislocation group (p < 0.001). The anterolateral alpha angle that indicated an increased dislocation risk was ≥47°. CONCLUSIONS: Acetabular retroversion, posterior acetabular undercoverage, and cam-type FAI morphology may be risk factors contributing to traumatic posterior hip dislocation in high-energy trauma mechanisms. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

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.

3D pre-operative planning and patient-specific guides for re-directional peri-acetabular osteotomy in children and adolescents.

Surgical procedures to correct hip dysplasia associated with subluxation or dislocation of the femoral head are complex. The 3D geometric abnormalities of the acetabulum and proximal femur vary across patients. We, therefore, suggest a patient-specific surgical treatment involving computer-assisted 3D planning of the peri-acetabular osteotomies, taking into account the femoral head position; 3D printing of patient-specific guides for the cuts, repositioning, and fixation; and intra-operative application of the simulated displacements with their fixation. LEVEL OF EVIDENCE: IV.