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.

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.

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.

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.

Providing a computationally derived, mechanically optimised target correction during preoperative planning can improve joint contact mechanics of hip dysplasia treated with periacetabular osteotomy

AIM

Preoperative identification of acetabular corrections that optimally improve joint stability and reduce elevated contact stresses could further reduce osteoarthritis progression in patients with hip dysplasia who are treated with periacetabular osteotomy (PAO). The purpose of this study was to investigate how providing patient-specific, mechanically optimal acetabular reorientations to the surgeon during preoperative planning affected the surgically achieved correction.

METHODS

Preoperative CT scans were used to create patient-specific hip models for 6 patients scheduled for PAO. A simulated acetabular fragment was extracted from the preoperative pelvis model and computationally rotated to simulate candidate acetabular reorientations. For each candidate, discrete element analysis was used to compute contact stresses during walking, which were summed over the gait cycle and scaled by patient age to obtain chronic contact stress-time exposure. The ideal patient-specific reorientation was identified using a cost function that balances minimising chronic stress exposures and achieving surgically acceptable acetabular coverage angles. The optimal reorientation angles and associated contact mechanics were provided to the surgeon preoperatively. After PAO was performed, a model of the surgically achieved correction was created from a postoperative CT scan. Radiographic coverage and contact mechanics were compared between preoperative, optimal, and surgically achieved orientations.

RESULTS

While surgically achieved reorientations were not significantly different from optimal reorientations in radiographically measured lateral (p = 0.094) or anterior (p = 0.063) coverage, surgically achieved reorientations had significantly (p = 0.031) reduced total contact area compared to optimal reorientations. The difference in lateral coverage and peak chronic exposure between surgically achieved and optimal reorientations decreased with increasing surgeon experience using the models (R² = 0.758, R2 = 0.630, respectively).

CONCLUSIONS

Providing hip surgeons with a patient-specific, computationally optimal reorientation during preoperative planning may improve contact mechanics after PAO, which may help reduce osteoarthritis progression in patients with hip dysplasia.

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.

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.

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.

Neonatal Ultrasound and Radiographic Markers of Hip Dysplasia in Young Adults

OBJECTIVES

To examine radiologic outcomes at skeletal maturity of sonographically normal, immature, mildly, and severely dysplastic newborn hips.

METHODS

During 1988 to 1990, 11 925 newborns were enrolled in a randomized controlled trial examining screening strategies for developmental hip dysplasia. In total, 4469 were invited to clinical and radiologic follow-up 18 years later, of which 1735 had received neonatal ultrasound. Radiographic markers for dysplasia in left adult hips included the center-edge (CE) angle.

RESULTS

At follow-up, 984 of 1735 (56.7%) with newborn ultrasound met, of which 966 (614 females) had valid radiographs and were thus included. For females, 34 (10.2%) and 1 (0.3%) of the 332 sonographically normal left neonatal hips were judged borderline (20°≤ CE <25°) or dysplastic (CE <20°) at skeletal maturity respectively. Corresponding numbers were 36 (19.7%) and 3 (1.6%) of the 183 immature, 12 (15.6%) and 2 (2.6%) of the 77 mildly dysplastic, and 3 (13.6%) and 3 (13.6%) of the 22 severely dysplastic neonatal left hips (P ≤ .001). In males, no associations were found. In females, adult joint hypermobility was associated with sonographic neonatal hip instability (P = .046), as well as with adult acetabular dysplasia (P = .024).

CONCLUSIONS

Significant associations between neonatal hip phenotypes and adult dysplasia were revealed in females. This indicates the possibility of different mechanisms affecting the course of developmental dysplasia of the hip for females and males, prompting consideration of prolonged clinical and radiologic follow-up for females with dysplastic neonatal hips. Results in males are limited by low numbers of dysplastic hips. The significance of joint hypermobility warrants further investigation.

Minimally invasive femoral head fracture fixation using three-dimensional navigation: a technical note

Femoral head fractures are rare traumatic injuries that are usually associated with hip dislocations. Open reduction and internal fixation are performed when indicated, but can be associated with a higher risk of avascular necrosis. We report the case of a 24-year-old patient with a Pipkin type II fracture dislocation of the femoral head fixed via a minimally invasive three-dimensional navigated internal fixation technique. This technique minimizes deep soft tissue dissection to the hip capsule and associated vascularity and allows for accurate implant positioning.Level of evidence: Therapeutic case report Level IV.

Closed reduction of dislocated hip prosthesis using a traction table

This article describes three cases in which a dislocated hip prosthesis was reduced by a new reduction technique - that we previously described - using traction table. The dissociation of a prosthesis is a rare but serious complication of closed reduction manoeuvre. The new reduction manoeuvre using a traction table may be a good option to avoid dissociation of the prosthesis during closed reduction for treatment of dislocation after total hip arthroplasty.

Management of long bone fractures and traumatic hip dislocations in paediatric patients: study protocol for a prospective global multicentre observational cohort registry

INTRODUCTION

Management controversy and clinical equipoise exist in treatments of long bone fractures and traumatic hip dislocation in paediatric patients due to the lack of high-quality clinical evidence. This protocol describes the effort of a large prospective global multicentre cohort study (registry) aiming at providing quality data to assist evidence-based treatment decision-making.

METHODS AND ANALYSIS

Eligible paediatric patients (N=750-1000) with open physes suffering from proximal humerus fractures, distal humerus fractures, proximal radius fractures, forearm shaft fractures, traumatic hip dislocations, femoral neck fractures or tibial shaft fractures will be recruited over a period of 24-36 months. Hospitalisation and treatment details (including materials and implants) will be captured in a cloud-based, searchable database. Outcome measures include radiographic assessments, clinical outcomes (such as range of motion, limb length discrepancies and implant removal), patient-reported outcomes (Patient Reported Outcomes Of Fracture, Patient-Reported Outcomes Measurement Information System (PROMIS) and EuroQol-5D (EQ-5D-Y)) and adverse events.Aside from descriptive statistics on patient demographics, baseline characteristics, types of fractures and adverse event rates, research questions will be formulated based on data availability and quality. A statistical analysis plan will be prepared before the statistical analysis.

ETHICS AND DISSEMINATION

Ethics approval will be obtained before patients are enrolled at each participating site. Patient enrolment will follow an informed consent process approved by the responsible ethics committee. Peer-reviewed publication is planned to disseminate the study results.

TRIAL REGISTRATION NUMBER

NCT04207892.

Step-cut osteotomy of the anterior superior iliac spine for increased visualisation in the Levine approach for Bernese periacetabular osteotomy surgery

BACKGROUND

Hip dysplasia can lead to pain and dysfunction in the young adult. Acetabular undercoverage leads to abnormal joint loading and results in joint degeneration, accelerating need for arthroplasty in this patient population. Conceptually, treatment focuses on increasing acetabular coverage in the form of periacetabular osteotomy. The procedure can be performed through the iliofemoral approach, and performing an anterior superior iliac spine (ASIS) osteotomy can enhance the visualisation in this approach. Several techniques have been described for ASIS osteotomy.

AIM

The purpose this study was to report on step-cut technique for ASIS osteotomy during the Bernese periacetabular osteotomy procedure to enhance visualisation when utilising the iliofemoral approach.

SURGICAL TECHNIQUE

This step-cut technique enhances stability at the osteotomy site, and minimises soft tissue dissection to reduce pain and assists with maintaining a stable fixation construct postoperatively.

RESULTS

There were no nonunions and minimal morbidity to the lateral femoral cutaneous nerve injury in cohort of 86 patients while utilising this technique.

CONCLUSIONS

We recommend using this step-cut ostetomy of the ASIS during Bernese periactetabular osteotomy for benefit of increasing exposure while maintaining a low complication profile.

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.

Intermediate to Long-Term Results Following Traumatic Hip Dislocation: Characteristics, CT-Based Analysis, and Patient-Reported Outcome Measures

BACKGROUND

Traumatic hip dislocation is a rare yet severe injury. As the long-term morbidity, subsequent complications, and clinical outcomes are nearly unknown, we aimed to analyze traumatic hip dislocations and identify specific factors that may predict the clinical outcome.

METHODS

Data on injury-related characteristics and computed tomographic (CT) scans for all consecutive adult patients who had been managed for traumatic hip dislocation between 2009 and 2021 were analyzed. At the time of follow-up, the patients were assessed with regard to osteonecrosis, posttraumatic osteoarthritis (OA), further operations and complications, return to sports and work, and patient-reported outcome measures (PROMs), including the Tegner Activity Scale and modified Harris hip score.

RESULTS

One hundred and twelve patients (mean age [and standard deviation], 43.12 ± 16.6 years) were included. Associated acetabular rim and femoral head fractures (Pipkin Type I to IV) were observed in 44% and 40% of patients, respectively. Concomitant injuries occurred in 67% of the patients, most commonly involving the knee (29% of patients). Sixty-nine patients (61.6%) were available for follow-up; the mean duration of follow-up was 6.02 ± 3.76 years. The rates of osteonecrosis and posttraumatic OA were 13% and 31.9%, respectively, and were independent of the timing of hip reduction, leading to subsequent total hip arthroplasty (THA) in 19% of patients. Sciatic nerve injury occurred in 27.5% of the patients who were available for follow-up. Both THA and sciatic nerve injury were associated with posterior acetabular rim or Pipkin Type-IV fractures (p < 0.001). Only 33.3% of the patients returned to their pre-injury level of sports, 24.6% did not return to work, and 27.5% reported having sexual dysfunction. PROMs (Tegner Activity Scale, modified Harris hip score) were significantly worse in patients with osteonecrosis, posttraumatic OA, or residual sciatic nerve injury (p < 0.05).

CONCLUSIONS

Traumatic hip dislocations are predominantly associated with Pipkin and acetabular rim fractures, leading to overall limitations of activities of daily living, sports, and sexual function at intermediate to long-term follow-up. Patients with associated acetabular rim or Pipkin Type-IV fractures are most likely to require THA for the treatment of osteonecrosis or posttraumatic OA and are at greater risk for sustaining sciatic nerve injury.

LEVEL OF EVIDENCE

Prognostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

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.

Anterior hip dislocation: A current concepts review and proposal of management algorithm

Anterior hip dislocations as compared to posterior, rarely occurs. Nevertheless, it is important to be prepared to manage it. Physical examination and imaging are crucial in detecting this type of dislocation and ruling out any associated fractures. The most important thing is not delaying reduction which is done in a closed manner preferably in the operating room and under general anesthesia. Post-operative complications should be monitored. As for rehabilitation it is still debated and no consensus was reached.

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.

Hip dysplasia hiding in plain sight: A retrospective analysis of radiology reports

INTRODUCTION

Timely recognition of dysplastic hip morphology is critical to facilitate appropriate management before significant joint damage has developed. It is likely that radiologist under reporting contributes to delays in diagnosis. This study aimed to assess how often adult hip dysplasia goes undetected in radiological reports and to identify clinical and radiological variables that impact the likelihood of detection of dysplasia by radiologists.

METHODS

Referral details and radiology reports of patients who underwent periacetabular osteotomy by a single surgeon for symptomatic hip dysplasia between 1 January 2016 and 30 June 2020 were reviewed. Four assessors measured the lateral centre edge angle from the pelvic radiograph performed at time of referral. Film quality and other radiographic parameters were also assessed.

RESULTS

Sixty-eight patients were included, 84% were female and the median age was 28.1 years. Dysplasia was not documented in the radiology report in 49% of cases. Dysplasia was more likely to be reported with no history of injury, an aspherical femoral head, lower lateral centre edge angle, higher acetabular index, increased femoral head shaft angle, higher femoro-epiphyseal acetabular roof index, or if there was disruption of Shenton's line, with the first three variables being independent predictors of radiologist detection.

CONCLUSION

Hip dysplasia should be considered in all adolescents/young adults presenting with hip pain. Causes of radiologist under reporting are likely multifactorial. Clinical information can cause cognitive biases and result in selective looking. A systematic approach to pelvis radiographs should include assessment of acetabular coverage and active search for evidence of femoral head migration.

The relationship between hip displacement, scoliosis, and pelvic obliquity in 106 nonambulatory children with cerebral palsy: a longitudinal retrospective population-based study

BACKGROUND AND PURPOSE

The relationship between hip displacement (HD), pelvic obliquity (PO), and scoliosis in nonambulatory children with cerebral palsy (CP) has not been clearly elucidated. The aims of this population-based study were to examine the prevalence and temporal sequence of these deformities in nonambulatory children with CP and to evaluate how probable it is that severe unilateral HD contributes to development of scoliosis.

PATIENTS AND METHODS

This longitudinal study comprised 106 nonambulatory children, enrolled in a surveillance program. Pelvic radiographs for measurements of migration percentage (MP) and PO were taken once a year from the diagnosis of HD. Spine radiographs were taken in patients with clinically detected scoliosis. Radiographic follow-up continued until skeletal maturity.

RESULTS

Clinically significant scoliosis (Cobb angle ≥ 40°) occurred in 60 patients at a mean age of 11.8 years. 65 patients developed clinically significant HD (MP ≥ 40%) at a mean age of 4.8 years. 24 patients had no significant hip or spine deformities, 22 had HD only, 17 had scoliosis only, and 43 had both deformities. HD was diagnosed before scoliosis in all except 1 of the patients with both deformities. 14 of 19 patients with severe unilateral HD (MP ≥ 60%) had scoliosis convexity to the opposite side of the displaced hip.

CONCLUSION

The combination of scoliosis and HD was frequent, and HD was diagnosed first in almost all the patients. HD might be a contributory cause of scoliosis in patients with severe, unilateral HD, PO, and later scoliosis with convexity to the opposite side.

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.

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.

Pain, function and quality of life are impaired in adults undergoing periacetabular osteotomy (PAO) for hip dysplasia: a systematic review and meta-analysis

BACKGROUND

Hip dysplasia is a common condition in active adults with hip pain that can lead to joint degeneration. Periacetabular osteotomy (PAO) is a common surgical treatment for hip dysplasia. The effect of this surgery on pain, function and quality of life (QOL) has not been systematically analysed.

PURPOSE

In adults with hip dysplasia: (1) evaluate differences in pain, function and QOL in those undergoing PAO and healthy controls; (2) evaluate pre- to post-PAO changes in pain, function and QOL; (3) evaluate differences in pain, function and QOL in those with mild versus severe dysplasia, undergoing PAO; and (4) evaluate differences in pain, function and QOL in those having primary PAO versus those with previous hip arthroscopy.

METHODS

A comprehensive, reproducible search strategy was performed on 5 different databases. We included studies that assessed pain, function and QOL in adults undergoing PAO for hip dysplasia, using hip-specific patient reported outcomes measures.

RESULTS

From 5017 titles and abstracts screened, 62 studies were included. Meta-analysis showed PAO patients had worse outcomes pre- and post-PAO compared to healthy participants. Specifically, pain (standardised mean difference [SMD] 95% confidence interval [CI]): -4.05; -4.78 to -3.32), function (-2.81; -3.89 to -1.74), and QOL (-4.10; -4.43 to -3.77) were significantly poorer preoperatively.Meta-analysis found patients experienced improvements following PAO. Pain improved from pre-surgery to 1-year (standardised paired difference [SPD] 1.35; 95% CI, 1.02-1.67) and 2 years postoperatively (1.35; 1.16-1.54). For function, the activities of daily living scores at 1 year (1.22; 1.09-1.35) and 2 years (1.06; 0.9-1.22) and QOL at 1 year (1.36; 1.22-1.5) and 2 years (1.3; 1.1-1.5) all improved. No difference was found between patients undergoing PAO with mild versus severe dysplasia.

CONCLUSIONS

Before undergoing PAO surgery, adults with hip dysplasia have worse levels of pain, function and QOL compared to healthy participants. These levels improve following PAO, but do not reach the same level as their healthy participants.

REGISTRATION

PROSPERO (CRD42020144748).

[What surgical treatment for femoro-acetabular impingement?]

Femoroacetabular impingement (FAI) is a frequent cause of hip pain in young people and athletes. It requires a complete work-up, including X-rays, hip arthro-MRI and CT coxometry with measurement of femoral torsion. The surgical management of CFA must be adapted to the morphological anomalies of the femur (cam), acetabulum (pincer) and femoral torsional disorders. Most CFA can be treated by hip arthroscopy, with correction of the cam and suture of the labrum. Some CFA with a bulky or posterior cam require surgical hip dislocation. A femoral rotation or derotation osteotomy can correct an associated torsional disorder. In cases of marked retroversion of the acetabulum, anteverting periacetabular osteotomy can reorient the acetabulum.