Anthony Cooper

Arthroscopic treatment of femoroacetabular impingement following slipped capital femoral epiphysis

UNLABELLED Slipped capital femoral epiphysis (SCFE) may lead to symptomatic femoroacetabular impingement (FAI). We report our experience of arthroscopic treatment, including osteochondroplasty, for the sequelae of SCFE. Data were prospectively collected on patients undergoing arthroscopy of the hip for the sequelae of SCFE between March 2007 and February 2013, including demographic data, radiological assessment of the deformity and other factors that may influence outcome, such as the presence of established avascular necrosis. Patients completed the modified Harris hip score (mHHS) and the non-arthritic hip score (NAHS) before and after surgery. In total, 18 patients with a mean age of 19 years (13 to 42), were included in the study. All patients presented with pain in the hip and mechanical symptoms, and had evidence of FAI (cam or mixed impingement) on plain radiographs. The patients underwent arthroscopic osteoplasty of the femoral neck. The mean follow-up was 29 months (23 to 56). The mean mHHS and NAHS scores improved from 56.2 (27.5 to 100.1) and 52.1 (12.5 to 97.5) pre-operatively to 75.1 (33.8 to 96.8, p = 0.01) and 73.6 (18.8 to 100, p = 0.02) at final follow-up, respectively. Linear regression analysis demonstrated a significant association between poorer outcome scores and increased time to surgery following SCFE (p < 0.05 for all parameters except baseline MHHS). Symptomatic FAI following (SCFE) may be addressed using arthroscopic techniques, and should be treated promptly to minimise progressive functional impairment and chondrolabral degeneration. TAKE HOME MESSAGE Arthroscopy of the hip can be used to treat femoroacetabular impingement successfully following SCFE. However, this should be performed promptly after presentation in order to prevent irreversible progression and poorer clinical outcomes.

Evidence-based Management of Developmental Dysplasia of the Hip

Developmental Dysplasia of the Hip (DDH) refers to a spectrum of abnormalities involving the developing hip. These abnormalities range from mild instability to frank dislocation of the joint. It is important to treat the condition effectively in order to encourage the hip to develop normally and produce good long-term results. This article reviews the evidence related to the treatment of DDH. The quality of evidence for DDH management remains low, with little uniformity in terminology and most studies being retrospective in nature. Given this, it is not possible to recommend or reject most treatment modalities based on existing studies.

The contralateral foot in children with unilateral clubfoot, is the unaffected side normal?

The unilateral unaffected clubfoot has previously been used as a control in longitudinal studies of clubfoot outcomes. However, we have observed that the unaffected clubfoot does not necessarily exhibit the same pedobarographic measurements as seen in normal control subjects. The purpose of this study was to evaluate whether the unaffected foot is indeed normal or if there are differences in the pedobarographic measurements of the unaffected foot compared to healthy normal controls.The Tekscan HR Mat™ was used to dynamically test the walking pattern of 103 subjects with unilateral clubfeet and compare the results to our previously published series of normal controls. Patients were divided into three groups: Group 1 (< 2 years), Group 2 (2-5 years) and Group 3 (>5 years). An unpaired t-test (p < 0.05) was used to compare percentage of stance at initiation of force, the percentage of stance at maximum force, the percentage of stance at termination of force, the maximum percentage force and the average force/time integral between a group of normal age matched controls and the unaffected foot in patients with unilateral clubfoot. Significant differences were identified between the unaffected side and normal controls for the pressure distribution, order of initial contact and foot contact time. These differences evolved and changed with age. The pedobarographic measurements of patients with clubfoot are not normal for the unaffected foot. As such the unaffected foot should not be referred to as normal, nor should it be used as a control.

Relationships Between Severity of Deformity and Impingement in Slipped Capital Femoral Epiphysis.

Background: In situ pinning, a low-risk treatment for slipped capital femoral epiphysis (SCFE), leaves the slipped femoral head in place and may reduce range of motion (ROM) and cause impingement. It is unclear when a more complex surgery should be considered, because the relationships between severity, slip stability, remodeling, impingement, and ROM are unknown. Research questions: (1) Do more severe acute SCFE deformities (no bony remodeling) result in a greater loss of flexion ROM? (2) Does the presence or location of impingement on the pelvis vary with severity of acute SCFE deformity? Methods: We developed a 3D geometric model of acute SCFE deformity from 1 computed tomography scan of a normal adolescent hip. Ethics board approval was obtained from our institution. Bone models were created from the segmented pelvis, epiphysis, and subphyseal femur. In total, 3721 SCFE deformities were simulated by combining posterior and inferior slips in the axial and coronal planes, respectively. Southwick angles were estimated from a frog-leg lateral projection. Deformities were divided into mild (0 to 30 degrees), moderate (30 to 60 degrees), and severe (≥60 degrees) Southwick groups. Each joint was flexed in combination with internal/external rotation until contact occurred. A total of 121 ROM trials, with different degrees of internal/external rotation (0 to 90 degrees at 1.5-degree steps) were performed for each deformity. Results: In total, 3355 simulated SCFE deformities (363 could not be rotated out of impingement) were analyzed. Increasing slip severity reduced flexion ROM across the range of internal/external rotation. Contact occurred for most mild deformities, and for all moderate and severe deformities in at least 1 ROM trial. Impingement was observed mainly on the anterosuperior aspect of the acetabulum. Conclusions: Increasing slip severity in acute SCFE reduced flexion and increased incidence of impingement, primarily occurring on the anterosuperior aspect of the acetabulum. The impingement patterns observed are consistent with damaged cartilage locations seen in clinical literature. Clinical Relevance: In this experimental model, moderate and severe acute slips in SCFE lead to reduced ROM and impingement with the acetabulum. This suggests that in situ pinning may result in impingement of moderate and severe acute SCFE slips.

Towards Reliable Automatic Characterization of Neonatal Hip Dysplasia from 3D Ultrasound Images

Ultrasound (US) imaging is recommended for early detection of developmental dysplasia of the hip (DDH), which includes a spectrum of hip joint abnormalities in infants. However, the currently standard 2-dimensional (2D) US-based approach to measuring the dysplasia metric (DM), namely the \(\alpha \) angle, suffers from high within-hip variability with standard deviations typically ranging between \(3^{\circ }-7^{\circ }\). Such high variability leads to elevated over- and under-treatment rates in hip classification. To reduce this high variability inherent to the 2D \(\alpha \) angle, \(\alpha _{2D}\), we propose a 3D US-based DM in the form of a 3D \(\alpha \) angle, \(\alpha _{3D}\), that more accurately characterizes the morphology of an infant’s hip joint. Our method leverages phase symmetry features that automatically identify the 3D bone/cartilage structures to compute \(\alpha _{3D}\). Validating on 30 clinical patient hip examinations, we demonstrate the within-hip variability of \(\alpha _{3D}\) to be significantly smaller than \(\alpha _{2D}\) (\(28.9\,\%\) reduction, \(p<0.01\)). Our findings indicate that \(\alpha _{3D}\) may be significantly more reproducible than the conventional 2D measure, which will likely reduce misclassification rates.

What Clinimetric Evidence Exists for Using Hip-specific Patient-reported Outcome Measures in Pediatric Hip Impingement?

BackgroundPatient-reported outcomes (PROs) are an increasingly popular research tool used to evaluate the outcomes of surgical intervention. If applied appropriately, they can be useful both for disease monitoring and as a method of assessing the efficacy of treatment. Many disorders can lead to impingement in children and adolescents, but it is not clear if any PROs have been validated to evaluate outcomes in these populations.Questions/purposesWe performed a systematic review of the literature to answer the following research questions: (1) Which hip-specific PROs are used in pediatric populations with impingement? (2) What clinimetric evidence exists for the use of these specific PROs in this population?MethodsWe performed two systematic searches of three databases (Medline, EMBASE, and Ovid All EBM Reviews). The first search aimed to identify specific PROs that have been applied to pediatric impingement populations. The second search aimed to find clinimetric evaluations of the PROs from the first search in this population.ResultsWe found six hip-specific PROs applied in pediatric impingement: Harris Hip Score, modified Harris Hip Score, Iowa Hip Score, Merle d’Aubigné Hip Score, Hip Outcome Score, and Non-arthritic Hip Score. However, we found no papers validating any of these PROs in this population. Furthermore, we found no papers validating any of these PROs in any pediatric population.ConclusionsA number of adult PROs have been applied in pediatric impingement disorders without evidence of validation in any pediatric population. Further work to develop and validate a hip-specific pediatric PRO is required.

Automatic Near Real-Time Evaluation of 3D Ultrasound Scan Adequacy for Developmental Dysplasia of the Hip

Accurate detection and diagnosis of developmental dysplasia of the hip (DDH), a common hip instability condition among infants, relies heavily on acquiring adequate ultrasound (US) image data. Although 2D US is the standard modality used for DDH screening, 3D US has recently been considered as well. Presently there is no automatic method (or even a standardized manual method) capable of analyzing the US volume to determine whether that volume is adequate for extracting DDH metrics required for diagnosis. Scan adequacy in 2D has seen only one work on automation and there has been no work done on scan adequacy in 3D. We propose an automatic, near real-time method of assessing 3D ultrasound scans in developmental dysplasia screening and diagnostic applications using a convolutional neural network (CNN). Our classifier labels volumes as adequate or inadequate for subsequent interpretation based on the presence of hip anatomy needed for DDH diagnosis. We validate our approach on 40 datasets from 15 pediatric patients and demonstrate a classification rate of 100% with average processing time of just above 2 s per US volume. We expect automatic US scan adequacy assessment to have significant clinical impact with the potential to help in imaging standardization, improving efficiency of measuring DDH metrics, and improving accuracy of clinical decision making.

Real Time RNN Based 3D Ultrasound Scan Adequacy for Developmental Dysplasia of the Hip

Acquiring adequate ultrasound (US) image data is crucial for accurate diagnosis of developmental dysplasia of the hip (DDH), the most common pediatric hip disorder affecting on average one in every one thousand births. Presently, the acquisition of high quality US deemed adequate for diagnostic measurements requires thorough knowledge of infant hip anatomy as well as extensive experience in interpreting such scans. This work aims to provide rapid assurance to the operator, automatically at the time of acquisition, that the data acquired are suitable for accurate diagnosis. To this end, we propose a deep learning model for a fully automatic scan adequacy assessment of 3D US volumes. Our contributions include developing an effective criteria that defines the features required for DDH diagnosis in an adequate 3D US volume, proposing an efficient neural network architecture composed of convolutional layers and recurrent layers for robust classification, and validating our model’s agreement with classification labels from an expert radiologist on real pediatric clinical data. To the best of our knowledge, our work is the first to make use of inter-slice information within a 3D US volume for DDH scan adequacy. Using 200 3D US volumes from 25 pediatric patients, we demonstrate an accuracy of 82% with an area under receiver operating characteristic curve of 0.83 and a clinically suitable runtime of one second.

A 3D Femoral Head Coverage Metric for Enhanced Reliability in Diagnosing Hip Dysplasia

Developmental dysplasia of the hip (DDH) in infancy refers to hip joint abnormalities ranging from mild acetabular dysplasia to irreducible femoral head dislocations. While 2D B-mode ultrasound (US) is currently used clinically to estimate the severity of femoral head subluxation in infant hips, such estimates suffer from high inter-exam variability. We propose using a novel 3D US-derived dysplasia metric, the 3D femoral head coverage (\(FHC_{3D}\)), which characterizes the 3D morphology of the femoral head relative to the vertical cortex of the ilium in an infants hip joint. We compute our 3D dysplasia metric by segmenting the femoral head using a voxel-wise probability map based on a tomographic reconstruction of 2D cross-sections each labeled with a probability score of that slice containing the femoral head. Using a dataset of 20 patient hip examinations, we demonstrate that our reconstructed femoral heads agree reasonably well with manually segmented femoral heads (mean dice coefficient of 0.71), with a significant reduction in variability of the associated metric relative to the existing manual 2D-based FHC ratio (\({\sim } 20\%\) reduction, \(p<0.05\)). Our findings suggest that the proposed 3D dysplasia metric may be more reliable than the conventional 2D metric, which may lead to a more reproducible test for diagnosing DDH.

Evidence-Based Treatment for Congenital Femoral Deficiency

Congenital femoral deficiency is a challenging paediatric orthopaedic problem that requires a multidisciplinary approach. Patients vary significantly in term of severity from a very mild form that does not require surgical intervention to complete absence of femur. Various surgical interventions have been reported in the literatures with variable success rates. Given the rarity of the condition, the wide spectrum of severity, the many surgical interventions that have been described and the recent evolution in surgical techniques, it has been difficult to recommend “the best treatment” for this condition. In this chapter, we critically reviewed the evidence behind the core principle of treating this challenging condition.