Osteonecrosis of the Femoral Head: Update Article / Osteonecrose da cabeça femoral: Artigo de atualização

Abstract Among the pathologies that affect the hip joint, osteonecrosis of the femoral head (ONFH) is probably the most intriguing and challenging. It consists of a multifactorial disease with a highly-variable spectrum in its clinical presentation. It has a devastating effect, due to disabling painful conditions, both for usual activities and sports. Given the huge range of risk factors, such as prolonged use of corticosteroids (especially in cases of rheumatologic diseases), trauma sequelae, sickle cell anemia, HIV, alcoholism, smoking, blood dyscrasias, and several other diseases that compromise the blood supply to the femoral head, ONFH has a varied clinical presentation and prognosis, which makes it difficult to determine a specific treatment, especially in cases in which chondral involvement has not yet occurred and the hip joint is still preserved. These are the main factors found in the literature that determine the classifications of this pathology. The range of treatments includes several options for cases in which an attempt is made to save the joint: conservative treatment, traditional decompression and/or combined with some type of adjuvant treatment (homologous grafting, synthetic grafting, vascularized grafts, tantalum screws, and bone marrow aspirate injection), and, for cases in which there is already a subchondral fracture and/or collapse of the femoral head and/or a reduction in the joint space, femoral osteotomies or total hip arthroplasty are commonly performed.

Resumo Entre as patologias que acometem a articulação coxofemoral, a osteonecrose da cabeça femoral (ONCF) é provavelmente a mais intrigante e desafiadora. Consiste em uma doença multifatorial, com um espectro muito variável em sua apresentação clínica. Tem efeito devastador, devido a quadros dolorosos incapacitantes tanto para atividades habituais quanto esportivas. Dada a gama enorme de fatores de risco, tais como uso prolongado de corticoides (principalmente em casos de doenças reumatológicas), sequelas de trauma, anemia falciforme, HIV, etilismo, tabagismo, discrasias sanguíneas, e várias outras doenças que comprometem a irrigação sanguínea da cabeça femoral, a ONCF tem apresentação clínica e prognósticos bem variados, o que dificulta a determinação de um tratamento específico, especialmente em casos nos quais ainda não houve acometimento condral e a articulação do quadril ainda se mantém preservada, sendo estes os principais fatores encontrados na literatura que determinam as classificações desta patologia. No leque de tratamentos, encontramos diversas opções para os casos em que setenta salvar a articulação: tratamento conservador, descompressão simples e/ou associada a algum tipo de tratamento adjuvante (enxertia homóloga, enxertia sintética, enxertos vascularizados, parafusos de tântalo, e injeção de aspirado de medula óssea), e, para casos nos quais já há fratura subcondral e/ou colapso da cabeça femoral e/ou diminuição do espaço articular, reserva-se, comumente, a realização de osteotomias femorais ou artroplastia total do quadril.

Morphological variants to predict outcome of avascular necrosis in developmental dysplasia of the hip.

AIMS: The most important complication of treatment of developmental dysplasia of the hip (DDH) is avascular necrosis (AVN) of the femoral head, which can result in proximal femoral growth disturbances leading to pain, dysfunction, and eventually to early onset osteoarthritis. In this study, we aimed to identify morphological variants in hip joint development that are predictive of a poor outcome. METHODS: We retrospectively reviewed all patients who developed AVN after DDH treatment, either by closed and/or open reduction, at a single institution between 1984 and 2007 with a minimal follow-up of eight years. Standard pelvis radiographs obtained at ages one, two, three, five, and eight years, and at latest follow-up were retrieved. The Bucholz-Ogden classification was used to determine the type of AVN on all radiographs. Poor outcome was defined by Severin classification grade 3 or above on the latest follow-up radiographs and/or the need for secondary surgery. With statistical shape modelling, we identified the different shape variants of the hip at each age. Logistic regression analysis was used to associate the different modes or shape variants with poor outcome. RESULTS: In all, 135 patients with AVN were identified, with a minimum of eight years of follow-up. Mean age at time of surgery was 7.0 months (SD 0.45), and mean follow-up was 13.3 years (SD 3.7). Overall, 46% had AVN type 1 while 54% type 2 or higher. More than half of the patients (52.6%) had a poor outcome. We found 11 shape variants that were significantly associated with a poor outcome. These shape variants were predominantly linked to AVN type 2 or higher. CONCLUSION: Specific morphological characteristics on pelvis radiographs of AVN hips were predictive for poor outcome, at a very young age. There was an overall stronger association to Bucholz-Ogden types 2-3-4 with the exception of two modes at age two and five years, linked to AVN type 1. Cite this article: Bone Joint J 2021;103-B(5):999-1004.

Identification of an IGF1 mutation (c.15+3G>A) in familial osteonecrosis of the femoral head: A case report.

RATIONALE: Osteonecrosis of the femoral head is a common orthopedic disease. Some studies have shown that osteonecrosis of the femoral head is related to susceptibility genes, but there are few reports of familial osteonecrosis of the femoral head. Here, we reported two first-degree relatives with osteonecrosis of the femoral head. PATIENT CONCERNS: A 27-year-old man with bilateral hip pain was diagnosed with osteonecrosis of the femoral head. The patient's mother also had a history of this disease. DIAGNOSES: Whole exome sequencing revealed the same mutation (c.15+3G>A) in the insulin-like growth factor 1 (IGF1) gene of the proband and his mother but not in his elder sister. INTERVENTIONS: The patient underwent bilateral total hip arthroplast. OUTCOMES: The patient recovered well, and was discharged. LESSONS: We found a heterozygous mutation (c.15+3G>A) in IGF1 in this family, which could be related to osteonecrosis of the femoral head. Early genetic counseling and gene locus detection could, thus, prove helpful for early diagnosis of osteonecrosis of the femoral head.

Efficacy of extracorporeal shock wave combined spinal core decompression for the treatment of patients with femoral head necrosis: A protocol for systematic review and meta-analysis.

BACKGROUND: Previous studies have reported that extracorporeal shock wave (EPSW) combined spinal core decompression (SCD) has been used for the treatment of patients with femoral head necrosis (FHN) effectively. However, their results are still inconsistent. Therefore, this study will systematically assess the efficacy and safety of EPSW and SCD for the treatment of patients with FHN. METHODS: This study will systematically search the following databases from inception through March 1, 2020: MEDLINE, Web of Science, Scopus, EMBASE, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, and China National Knowledge Infrastructure. All searches will be performed without language and publication date restrictions. This study will only include randomized controlled trials investigating the efficacy and safety of EPSW and SCD for the treatment of patients with FHN. Two authors will independently assess all literatures, extract data, and appraise risk of bias. Any confusion between 2 authors will be cleared up by a third author through discussion. RevMan 5.3 software will be utilized to analyze the data and to perform a meta-analysis if necessary. RESULTS: This study will summarize up-to-date evidence and provide a detailed summary related to the efficacy and safety of EPSW and SCD for the treatment of patients with FHN. CONCLUSION: This study may provide helpful evidence to determine whether or not EPSW combined SCD is effective and safety for the treatment of patients with FHN. SYSTEMATIC REVIEW REGISTRATION: INPLASY202040092.

Involvement of tumor necrosis factor alpha in steroid-associated osteonecrosis of the femoral head: friend or foe?

BACKGROUND: The etiology and pathology osteonecrosis of the femoral head (ONFH) are not completely clarified. As a cytokine participating in systemic inflammation, tumor necrosis factor alpha (TNFα) has been shown to be involved in the pathogenesis of ONFH. However, the role of TNFα in ONFH is not clearly clarified. In the present study, we investigated the effects of TNFα on proliferation, angiogenesis, and osteogenic differentiation of rat bone mesenchymal stem cells (rMSCs) and the underlying mechanisms. METHODS: All femoral bone tissues were separated in surgeries. After extracting total RNA and protein, we evaluated TNFα content by ELISA and the relative expression levels of genes by quantitative real-time PCR and western blot. Also, immunohistochemistry staining was performed to observe the expression of Runx2 in the bone samples. Chick embryo chorioallantoic membrane (CAM) assay was performed to observe the effect of TNFα on angiogenesis. The genomic DNAs were treated by bisulfite modification, and methylation status of CpG sites in the CpG islands of human and rat Runx2 gene promoter was determined by DNA sequencing. The binding of H3K4me3 and H3K27me3 in Runx2 promoter was checked by ChIP assay. RNA-seq analysis was used to find out the genes and pathways changed by TNFα in rMSCs. RESULTS: The results demonstrate TNFα promotes cell proliferation and angiogenesis whereas inhibits osteogenesis. Epigenetic regulations including DNA methylation and histone modifications play important roles in mediating the effect of TNFα on osteogenic differentiation. We find an increased rate of CpG methylation in rat Runx2 promoter in TNFα-treated rMSCs, as well as significantly increased occupancy of H3K27me3 in Runx2 gene promoter. The content of TNFα in necrotic tissue is much lower than that of normal tissue. And relevantly, human Runx2 promoter is demethylated in necrotic tissue using bone samples from patient with ONFH. In addition, we have observed that Wnt signaling pathway is inhibited by TNFα as multiple Wnts are markedly decreased in TNFα-treated rMSCs by RNA-seq analysis. CONCLUSION: Taken together, our study shows that TNFα plays complicated roles in the pathogenesis of ONFH, including proliferation, angiogenesis, and osteogenesis. Targeting TNFα should not be considered as an applicable strategy to inhibit the progression of ONFH.

Classification of Cruciate Ligament Dysplasia and the Severity of Congenital Fibular Deficiency.

BACKGROUND: Dysplasia of the cruciate ligaments has been found in many patients with congenital fibular deficiency. A recent classification system has shown that radiographic tibial spine changes can predict the hypoplasia and aplasia of the cruciate ligaments. We used this radiographic classification to determine the frequency of these abnormalities and how they correlate with the severity of fibular deficiency and lateral femoral condylar hypoplasia. METHODS: Using a hospital database search for fibular deficiency, 99 patients ≥6 years with unilateral fibular deficiency were identified. Existing radiographs of both knees were available for 75 patients and reviewed for the tibial spine changes and Achterman and Kalamchi classification of the fibular deficiency. Measurements of femoral condyle heights in 74 of 75 patients were recorded before any surgery to the distal femoral physis to assess lateral femoral condylar hypoplasia. RESULTS: Twenty-two patients had hypoplasia of the lateral tibial spine+normal medial spine, 29 had absence of the lateral tibial spine+hypoplastic medial spine, and 11 had absence of both tibial spines. Five tibial spines were normal and 8 were unclassifiable. The severity of the tibial spine dysplasia, particularly absence of the lateral tibial spine, correlated with the severity of the fibular deficiency. (P<0.0001) The mean lateral femoral condylar hypoplasia, measured by involved: uninvolved lateral condyle heights, was 0.85±0.11. Those with some preservation of the lateral tibial spine had less lateral femoral condylar hypoplasia (P=0.0009). This lateral femoral condylar hypoplasia was positively associated with the severity of the fibular absence (P=0.039) and foot ray deficiency (P=0.036). CONCLUSIONS: The severity of cruciate ligament dysplasia in fibular deficiency is directly correlated with the severity of fibular absence, lateral femoral condylar hypoplasia, and the absence of foot rays. This suggests that the embryological factors involved have a complex interplay for all of these clinical findings. LEVEL OF EVIDENCE: Level III.

Concurrent femoral head reduction and periacetabular osteotomies for the treatment of severe femoral head deformities.

AIMS: The aims of this study were to review the surgical technique for a combined femoral head reduction osteotomy (FHRO) and periacetabular osteotomy (PAO), and to report the short-term clinical and radiological results of a combined FHRO/PAO for the treatment of selected severe femoral head deformities. PATIENTS AND METHODS: Between 2011 and 2016, six female patients were treated with a combined FHRO and PAO. The mean patient age was 13.6 years (12.6 to 15.7). Clinical data, including patient demographics and patient-reported outcome scores, were collected prospectively. Radiologicalally, hip morphology was assessed evaluating the Tönnis angle, the lateral centre to edge angle, the medial offset distance, the extrusion index, and the alpha angle. RESULTS: The mean follow-up was 3.3 years (2 to 4.6). The modified Harris Hip Score improved by 33.0 points from 53.5 preoperatively to 83.4 postoperatively (p = 0.03). The Western Ontario McMasters University Osteoarthritic Index score improved by 30 points from 62 preoperatively to 90 postoperatively (p = 0.029). All radiological parameters showed significant improvement. There were no long-term disabilities and none of the hips required early conversion to total hip arthroplasty. CONCLUSION: FHRO combined with a PAO resulted in clinical and radiological improvement at short-term follow-up, suggesting it may serve as an appropriate salvage treatment option for selected young patients with severe symptomatic hip deformities.

Unaddressed Cam Deformity Is Associated with Elevated Joint Contact Stress After Periacetabular Osteotomy.

BACKGROUND: Femoral cam deformity is frequently present in patients with acetabular dysplasia. Computational modeling can be used to identify how this deformity affects joint mechanics. Our purpose was to identify the relationship between cam deformity and joint contact stress after periacetabular osteotomy (PAO). We hypothesized that cam deformity is associated with an increase in peak joint contact stress after PAO. METHODS: This was a retrospective review of patients treated for hip dysplasia with PAO without femoral osteochondroplasty. Patient-specific hip models created from preoperative and postoperative computed tomography (CT) scans were evaluated using discrete element analysis to determine maximum joint contact stress after PAO. Twenty hips with a postoperative increase in maximum contact stress were compared with 20 that demonstrated decreased maximum contact stress. Hips were assessed for cam deformity on cross-sectional imaging. Radiographic measures of acetabular dysplasia before and after PAO were assessed and compared with the change in maximum contact stress after PAO. RESULTS: There was a moderate relationship between the change in maximum contact stress and the α angle (r = 0.31; p = 0.04), and the average α angle in the hips with increased maximum contact stress was significantly different from that in the hips with decreased joint contact stress (51° ± 11.4° versus 42° ± 5.1°; p = 0.04). All 6 hips with an α angle of >60° demonstrated increased joint contact stress. CONCLUSIONS: Cam deformity is common in patients with hip dysplasia. In our study, α angles of >60° were associated with increased postoperative joint contact stress. The α angle should be assessed preoperatively, and deformity should be addressed for optimal joint mechanics after PAO. CLINICAL RELEVANCE: A reduction in joint contact stress is a proposed mechanism for the increased joint longevity following periacetabular osteotomy for hip dysplasia. Impingement from abnormal femoral offset negatively impacts clinical outcome, but this finding has not been evaluated from a biomechanical perspective previously and a threshold for performing femoral osteochondroplasty has not been established previously. This study provides biomechanical evidence supporting surgical management of femoral cam deformity for an α angle of >60°.

A Possible New Radiographic Predictor of Progression of Osteoarthritis in Developmental Dysplasia of the Hip: The Center Gap.

BACKGROUND: Patients with comparable severities of developmental dysplasia of the hip (DDH) may variably progress to osteoarthritis (OA) over time. Although joint congruency may be associated with OA progression in patients with DDH, it has only been assessed subjectively. We assessed the gap between the rotational centers of the acetabulum and femoral head (center gap) as a possible predictive measure of OA progression in patients with DDH. QUESTIONS/PURPOSES: In patients with bilateral DDH, we asked: (1) What is the probability of OA progression (Tönnis grade) or symptom development (pain) in the asymptomatic contralateral hip of patients with DDH undergoing unilateral joint-preserving surgery? (2) Is the center gap measurement associated with OA progression or symptom development in these hips? (3) Is the center gap measurement correlated with previous radiographic parameters? METHODS: A total of 297 patients (319 hips) underwent unilateral eccentric rotational acetabular osteotomy at our institution between July 1989 and December 1999. We performed no other joint-preserving surgery to treat patients with DDH during this timeframe. The inclusion criteria for the study were patients younger than 55 years of age, the contralateral hip classified as Tönnis Grade 0, no previous surgical interventions, and asymptomatic at the time of eccentric rotational acetabular osteotomy (155 patients, 155 hips). The exclusion criteria were a contralateral hip without dysplasia (four patients, four hips), loss to followup before 10 years (42 patients, 42 hips [27%]), or missing medical records or radiographs (21 patients, 21 hips [14%]). The remaining 88 patients (88 hips; 11 males and 77 females) with a mean age of 39 years (range, 17-53 years) and mean followup of 20 years (range, 10-27 years) were analyzed. From the institutional database, radiographic parameters including the center gap in the AP view were assessed using radiographs at the time of eccentric rotational acetabular osteotomy, and the Tönnis grade was recorded 1 year postoperatively and annually thereafter retrospectively. We defined migration of the rotational center of the femoral head based on the rotational center of the acetabulum in the horizontal plane as center gap X (mm) and in the vertical plane as center gap Y (mm) and defined the absolute value between the centers as center gap distance (mm). Using κ statistics, intra- and interobserver reliabilities were determined to be 0.896 and 0.857 for center gap X, 0.912 and 0.874 for center gap Y, and 0.912 and 0.901 for the center gap distance, respectively. When patients reported any contralateral ipsilateral hip pain during clinic visits, the hip was considered symptomatic. Kaplan-Meier survivorship analyses were performed with OA progression or symptom development in the nonoperative hip as the endpoint. Multivariate analyses were performed to assess risk factors for each outcome using the Cox proportional hazards model. Correlation analyses between the center gap and other parameters including lateral center-edge angle, femoral head extrusion index, acetabular depth-to-width index, femoral head lateralization, minimum width of the joint space, head sphericity, and joint congruency were performed using Pearson's correlation coefficient. RESULTS: At 20 years postoperatively, the probability of OA progression in the nonoperative hip was 13% (95% confidence interval [CI], 7.1-22.1) and the probability of symptom development was 34% (95% CI, 24.7-46.1). The center gap X measurements in the groups with OA progression (lateral 2.0 ± 2.1 [SD] mm) or symptom development (lateral 0.9 ± 2.4 mm) took a more lateral direction than those in the group without OA progression (medial 0.4 ± 2.1 mm) or symptom development (medial 0.5 ± 2.0 mm) (OA progression, p < 0.001; symptom development, p = 0.005). The center gap Y measurements in the groups with OA progression (distal 2.7 ± 7.1 mm) or symptom development (distal 2.1 ± 6.0 mm) took a more distal direction than those in the group without OA progression (proximal 1.6 ± 6.2 mm) or symptom development (proximal 2.5 ± 6.1 mm) (OA progression, p = 0.027; symptom development, p = 0.001). Independent risk factors for OA progression were the femoral head extrusion index (hazard ratio [HR], 1.11; 95% CI, 1.01-1.22; p = 0.028) and the center gap X (HR, 1.52; 95% CI, 1.07-2.16; p = 0.019), whereas no independent risk factors for symptom development were found. The center gap in the horizontal plane had no correlations with any other radiographic parameter studied. CONCLUSIONS: The center gap in the horizontal plane had a modest association with OA progression in this group of patients with DDH. Future studies are needed to determine the normal value of the center gap for patients without DDH and to assess the center gap in lateral radiographic views. LEVEL OF EVIDENCE: Level IV, prognostic study.

Three-dimensional MRI Analysis of Femoral Head Remodeling After Reduction in Patients With Developmental Dysplasia of the Hip.

BACKGROUND: Previous reports on patients with developmental dysplasia of the hip (DDH) showed that the prereduced femoral head was notably smaller and more nonspherical than the intact head, with growth failure observed at the proximal posteromedial area. We evaluated the shape of the femoral head cartilage in patients with DDH before and after reduction, with size and sphericity assessed using 3-dimensional (3D) magnetic resonance imaging (MRI). METHODS: We studied 10 patients with unilateral DDH (all female) who underwent closed reduction. Patients with avascular necrosis of the femoral head on the plain radiograph 1 year after reduction were excluded. 3D MRI was performed before reduction and after reduction, at 2 years of age. 3D-image analysis software was used to reconstruct the multiplanes. After setting the axial, coronal, and sagittal planes in the software (based on the femoral shaft and neck axes), the smallest sphere that included the femoral head cartilage was drawn, the diameter was measured, and the center of the sphere was defined as the femoral head center. We measured the distance between the center and cartilage surface every 30 degrees on the 3 reconstructed planes. Sphericity of the femoral head was calculated using a ratio (the distance divided by each radius) and compared between prereduction and postreduction. RESULTS: The mean patient age was 7±3 and 26±3 months at the first and second MRI, respectively. The mean duration between the reduction and second MRI was 18±3 months. The femoral head diameter was 26.7±1.5 and 26.0±1.6 mm on the diseased and intact sides, respectively (P=0.069). The ratios of the posteromedial area on the axial plane and the proximoposterior area on the sagittal plane after reduction were significantly larger than before reduction (P<0.01). CONCLUSIONS: We demonstrated that the size of the reduced femoral head was nearly equal to that of the intact femoral head and that the growth failure area of the head before reduction, in the proximal posteromedial area, was remodeled after reduction. LEVEL OF EVIDENCE: Level IV-case series.

Delays in diagnosis are associated with poorer outcomes in adult hip dysplasia.

Background and Aims Developmental dysplasia of the hip is a common cause of osteoarthritis. Periacetabular osteotomy can restore femoral head coverage; however, it is reserved for patients with minimal articular degeneration. We examined the relationship between delays in diagnosis and outcomes. Methods We identified patients presenting to a hip specialist with a new diagnosis of hip dysplasia. The time taken between patients presenting to their general practitioner and attending the young adult hip clinic was established. Patients were stratified into Early, Moderate and Late Referral groups. Hip and SF-12 questionnaires were completed. Radiographs were graded according to the Tönnis classification system and the outcome following hip specialist review documented. Results Fifty-one patients were identified. Mean time from attending a general practitioner to review at the young adult hip clinic was 40.4 months. Lower hip and SF-12 scores, and higher radiological osteoarthritis grades were found in the Moderate and Late Referral groups. A higher proportion of the Moderate and Late Referral group underwent total hip arthroplasty rather than periacetabular osteotomy. Conclusion Delays in referring a patient to a hip specialist are associated with poorer outcomes. We propose pelvic radiographs are requested early by general practitioners to allow prompt diagnosis and referral to a hip specialist.

Surgical Correction of Cam Deformity in Association with Femoroacetabular Impingement and Its Impact on the Degenerative Process within the Hip Joint.

BACKGROUND: Cam morphology in association with femoroacetabular impingement (FAI) is a recognized cause of hip pain and cartilage damage and proposed as a leading cause of arthritis. The purpose of this study was to analyze the functional and biomechanical effects of the surgical correction of the cam deformity on the degenerative process associated with FAI. METHODS: Ten male patients with a mean age of 34.3 years (range, 23.1 to 46.5 years) and a mean body mass index (and standard deviation) of 26.66 ± 4.79 kg/m underwent corrective surgery for cam deformity in association with FAI. Each patient underwent a computed tomography (CT) scan to assess acetabular bone mineral density (BMD), high-resolution T1ρ magnetic resonance imaging (MRI) of the hips to assess proteoglycan content, and squatting motion analysis as well as completed self-administered functional questionnaires (Hip disability and Osteoarthritis Outcome Score [HOOS]) both preoperatively and 2 years postoperatively. RESULTS: At a mean follow-up of 24.5 months, improvements in functional scores and squat performance were seen. Regarding the zone of impingement in the anterosuperior quadrant of the acetabular rim, the mean change in BMD at the time of follow-up was -31.8 mg/cc (95% confidence interval [CI], -11 to -53 mg/cc) (p = 0.008), representing a 5% decrease in BMD. The anterosuperior quadrant also demonstrated a significant decrease in T1ρ values, reflecting a stabilization of the cartilage degeneration. Significant correlations were noted between changes in clinical functional scores and changes in T1ρ values (r = -0.86; p = 0.003) as well as between the BMD and maximum vertical force (r = 0.878; p = 0.021). CONCLUSIONS: Surgical correction of a cam deformity in patients with symptomatic FAI not only improved clinical function but was also associated with decreases in T1ρ values and BMD. These findings are the first, to our knowledge, to show that alteration of the hip biomechanics through surgical intervention improves the overall health of the hip joint. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A long term follow-up study of the development of hip disease in Mucopolysaccharidosis type VI.

Hip problems in Mucopolysaccharidosis type VI (MPS VI) lead to severe disability. Lack of data on the course of hip disease in MPS VI make decisions regarding necessity, timing and type of surgical intervention difficult. We therefore studied the development of hip pathology in MPS VI patients over time. Data were collected as part of a prospective follow-up study. Standardized supine AP pelvis and frog leg lateral radiographs of both hips were performed yearly or every 2years. Image assessment was performed quantitatively (angle measurements) and qualitatively (hip morphology). Clinical burden of hip disease was evaluated by physical examination, six minute walking test (6MWT) and a questionnaire assessing pain, wheelchair-dependency and walking distance. A total of 157 pelvic radiographs of 14 ERT treated MPS VI patients were evaluated. Age at first image ranged from 2.0 to 21.1years. Median follow up duration was 6.8years. In all patients, even in the youngest, the acetabulum and os ilium were dysplastic. Coverage of the femoral head by the acetabulum improved over time, but remained insufficient. While the femoral head appeared normal in the radiographs at young age, the ossification pattern became abnormal in all patients over time. In all patients the distance covered in the 6MWT was reduced (median Z scores -3.3). Twelve patients had a waddling gait. Four patients were partially wheelchair-dependent and ten patients had limitations in their maximum walking distance. In conclusion, clinically significant hip abnormalities develop in all MPS VI patients from very early in life, starting with deformities of the os ilium and acetabulum. Femoral head abnormalities occur later, most likely due to altered mechanical forces in combination with epiphyseal abnormalities due to glycosaminoglycan storage. The final shape and angle of the femoral head differs significantly between individual MPS VI patients and is difficult to predict.

Rotational alignment of the knee is different in osteological specimens with and without a large cam deformity of the proximal femur.

PURPOSE: We studied a large osteological collection for differences in knee rotation based upon the presence or absence of a large cam deformity of the proximal femur. METHODS: We obtained 357 matched tibiae and femora from the Hamann-Todd Osteological Collection and measured: femoral head-neck alpha angle, anteroposterior axis (or Whiteside's line) at the distal femur relative to the posterior condylar axis, and position of the tibial tubercle with respect to the posterior condylar axis of the proximal tibia. We then divided these specimens into two groups based upon alpha angle <45° (Group 1, n = 73) or alpha angle >60° (Group 2, n = 122) and performed an independent samples t-test to evaluate for differences in measured parameters between groups using this subset of specimens. RESULTS: The mean alpha angles in Group 1 and 2 were 40.9° ± 3.3° and 67.0° ± 5.6°, respectively. Whiteside's line was externally rotated with respect to the posterior femoral condylar axis by a mean of 1.8° ± 6.8° in Group 1, vs. 3.0° ± 3.7° in Group 2 (p = 0.03). The tibial tubercle was externally rotated by a mean of 19.4° ± 6.8° in Group 1, versus 16.6° ± 5.1° in Group 2 (p = 0.003). CONCLUSIONS: Specimens with femoral head-neck alpha angle >60° demonstrated greater external rotation of the distal femur and a more internally-rotated tibial tubercle compared to specimens with an alpha angle <45°. Differences in anatomic characteristics of the knee may play a role in the development of patellofemoral pain in patients with a large cam deformity.

The fate of hips that are conservatively treated in multiple epiphyseal dysplasia.

We reviewed the radiologic and clinical outcomes of hip joints affected by multiple epiphyseal dysplasia in 40 patients. The average patient age was 9.6 years. All patients were followed up for an average of 7.2 years. No patient underwent surgical treatment. The variances of the center-edge angle and femoral head coverage had the greatest tendency to increase with conservative treatment and follow-up (P=0.011 and 0.015, respectively). The acetabular angle and the acetabular depth index at the first visit and the latest follow-up were statistically significantly different (P=0.046 and 0.027, respectively). According to the Stulberg classification, the severity of hip deformity became less severe with age, but this was not statistically significant (P=0.090). Larger improvements in Harris hip scores were identified after conservative treatment (P=0.003). Favorable midterm outcomes were obtained for the treatment of hip deformity in multiple epiphyseal dysplasia patients by conservative treatment.

Proximal femoral osteotomy in Legg-Calvé-Perthes disease using a monolateral external fixator: surgical technique, outcome, and complications.

Although external fixation methods have been described for proximal femoral osteotomy for various etiologies, none are dedicated to a single disease entity. Our study introduces a technique of proximal femoral osteotomy and fixation with a monolateral external fixator system in Legg-Calvé-Perthes disease (LCPD). Twenty-three patients (19 males, four females) with LCPD underwent surgery at our institute between 2004 and 2012. Varus osteotomy (group A, 11 hips) and valgus osteotomy (group B, 12 hips) were performed and the monolateral external fixator system was used. The average age of patients at surgery was 13 years (6-23 years) and the mean follow-up duration was 21 months (12-64 months). The mean angular correction of the varus osteotomy in group A was 20° (10°-28°) and the mean medial displacement was 21% (10-49%). The angular correction of valgus osteotomy in group B was 28° (14°-49°) and lateral displacement was 41% (38-58%). The mean fixation time was 14 weeks (8.4-31 weeks). Complications occurred in nine hips (39.1%) and included pin-tract infections (five), hip abduction contracture (one), nonunions (two), and refracture (one). Our surgical technique provides precise correction and stable fixation with minimal intervention. Therefore, the monolateral external fixator could be considered an acceptable alternative fixation device for the correction of proximal femoral deformities in patients with LCPD. LEVEL OF EVIDENCE: Level IV, case series.

Cam Deformity and Acetabular Dysplasia as Risk Factors for Hip Osteoarthritis.

OBJECTIVE: Cam deformity and acetabular dysplasia have been recognized as relevant risk factors for hip osteoarthritis (OA) in a few prospective studies with limited sample sizes. To date, however, no evidence is available from prospective studies regarding whether the magnitude of these associations differs according to sex, body mass index (BMI), and age. METHODS: Participants in the Rotterdam Study cohort including men and women ages 55 years or older without OA at baseline (n = 4,438) and a mean follow-up of 9.2 years were included in the study. Incident radiographic OA was defined as a Kellgren/Lawrence grade of ≥2 or a total hip replacement at follow-up. Alpha and center-edge angles were measured to determine the presence of cam deformity and acetabular dysplasia/pincer deformity, respectively. Odds ratios (ORs) were calculated to assess the associations between both deformities and the development of OA. RESULTS: Subjects with cam deformity (OR 2.11, 95% confidence interval [95% CI] 1.55-2.87) and those with acetabular dysplasia (OR 2.19, 95% CI 1.50-3.21) had a 2-fold increased risk of developing OA compared with subjects without deformity, while pincer deformity did not increase the risk of OA. Stratification analyses showed that the associations of cam deformity and acetabular dysplasia with OA were driven by younger individuals, whereas BMI did not influence the associations. Female sex appears to modify the risk of hip OA related to acetabular dysplasia. CONCLUSION: Individuals with cam deformity and those with acetabular dysplasia are predisposed to OA; these associations were independent of other well-known risk factors. Interestingly, both deformities predisposed to OA only in relatively young individuals. Therefore, early identification of these conditions is important.

What Are the Results of Surgical Treatment of Hip Dysplasia With Concomitant Cam Deformity?

BACKGROUND: Periacetabular osteotomy (PAO) is a reliable procedure to correct the deficient acetabular coverage in hips with developmental dysplasia. It is unclear how the presence of additional femoral cam-type deformity might influence the clinical and radiographic treatment results of PAO. QUESTIONS/PURPOSES: (1) Are there differences in clinical scores (WOMAC, EQ-5D) and examination findings (impingement sign) or radiographic measures of acetabular orientation and head sphericity after PAO for isolated acetabular dysplasia when compared with the combined pathology of dysplasia and additional femoral cam deformity? (2) Are these clinical and radiographic findings after combined surgical therapy for additional cam deformity influenced by different pathology-adjusted surgical techniques? METHODS: From July 2005 to December 2010, 86 patients (106 hips) underwent PAO for hip dysplasia. Surgical and outcome data were prospectively collected and retrospectively reviewed in a comparative observational study. Indications for surgery were a lateral center-edge angle less than 25° and hip pain for at least 6 months. The contraindications for surgery were advanced radiographic osteoarthritis (Kellgren-Lawrence Grade 3), incongruency of joint space, and patient age > 50 years. Depending on preoperative hip ROM, impingement test, and presence of a radiographically visible cam deformity, treatment allocation was performed: Group I: isolated PAO in patients without symptomatic asphericity, Group IIa: PAO with subsequent osteochondroplasty through arthrotomy for patients with symptomatic cam deformity and no labrochondral pathology, and Group IIb: arthroscopically assisted osteochondroplasty and additional labrochondral repair with subsequent PAO when patients had labrochondral lesions in addition to a symptomatic cam deformity. Clinical outcome (impingement test, EQ-5D, WOMAC) as well as radiographic parameters (lateral center-edge angle, crossover sign, alpha angle, osteoarthritis grade) were obtained after a mean followup of 63 ± 18 months (range, 31-102 months) and compared with the baseline data. Eleven patients (13%) were lost to followup. With the numbers available, our study had 80% power to detect a difference between Groups I and II of 10 points on the WOMAC scores. RESULTS: There was no difference in the increase of WOMAC scores in patients with PAO alone (Group I; preoperative score 74 ± 17 versus postoperative 91 ± 15, p = 0.033) when compared with PAO and concurrent osteochondroplasty (Groups II A and B preoperative 73 ± 19 versus postoperative 90 ± 13 p < 0.001). The mean postoperative alpha angles in Group II (38° ± 6°) improved when compared with preoperative values (56° ± 15°; p < 0.001) and were even lower than native offset alpha angles in Group I (47° ± 11°). Clinical scores as well as postoperative radiographic parameters were not different between patients with conventional osteochondroplasty alone (Group IIA) and patients with arthroscopically assisted cam resection and intraarticular labrochondral repair (Group IIB). CONCLUSIONS: With the numbers available, we detected no differences in outcome scores and radiographic results between patients who had been treated with PAO alone and patients who underwent combined PAO and offset correction for cam deformity. Although arthroscopically assisted treatment of advanced labrochondral lesions together with osteochondroplasty is possible during PAO and the results were not different in this small study when compared with patients with PAO and osteochondroplasty alone, the type and extent of damage that would indicate additional cartilage surgery over cam resection alone remain unclear. LEVEL OF EVIDENCE: Level III, therapeutic study.

Femoral Morphology in the Dysplastic Hip: Three-dimensional Characterizations With CT.

BACKGROUND: Hip dysplasia represents a spectrum of complex deformities on both sides of the joint. Although many studies have described the acetabular side of the deformity, to our knowledge, little is known about the three-dimensional (3-D) head and neck offset differences of the femora of dysplastic hips. A thorough knowledge of proximal femoral anatomy is important to prevent potential impingement and improve results after acetabular reorientation. QUESTIONS/PURPOSES: (1) Are there common proximal femoral characteristics in patients with symptomatic hip dysplasia undergoing periacetabular osteotomy (PAO)? (2) Where is the location of maximal femoral head and neck offset deformity in hip dysplasia? (3) Do certain subgroups of dysplastic hips more commonly have cam-type femoral morphology? (4) Is there a relationship between hip ROM as well as impingement testing and 3-D head and neck offset deformity? METHODS: Using our hip preservation database, 153 hips (148 patients) underwent PAO from October 2013 to July 2015. We identified 103 hips in 100 patients with acetabular dysplasia (lateral center-edge angle [LCEA] < 20°) and who had a Tönnis grade of 0 or 1. Eighty-six patients (86%) underwent preoperative low-dose pelvic CT scans at our institution as part of the preoperative planning for PAO. It is currently our standard to obtain preoperative low-dose pelvic CT scans (0.75-1.25 mSv, equivalent to three to five AP pelvis radiographs) on all patients before they undergo PAO unless a prior CT scan is performed at an outside institution. Hips with a history of a neuromuscular disorder, prior trauma, prior surgery, radiographic evidence of joint degeneration, ischemic necrosis, or Perthes-like deformities were excluded. Fifty hips in 50 patients met inclusion criteria and had CT scans available for review. Hips were analyzed with Dyonics Plan software and characterized with regard to version, neck-shaft angle, femoral head diameter, head and neck offset, femoral neck length, femoral offset, head center height, trochanteric height, and alpha angle. The maximum head and neck offset deformity was assessed using an entire clockface and an alpha angle ≥ 55° defined coexisting cam morphology. Subgroups included severity of lateral dysplasia: mild (LCEA 15°-20°) and moderate/severe (LCEA < 15°). Femoral version subgroups were defined as normal (5°-20°), decreased (≤ 5°), or increased (> 20°). The senior author (JCC) performed all physical examination testing. RESULTS: The mean LCEA was 14° (±4°), whereas the mean femoral anteversion was 19° (±12°). Eight hips (16%) demonstrated relative femoral retroversion (≤ 5°), whereas 26 (52%) showed excessive femoral anteversion (> 20°). Four hips (8%) had ≥ 35° of femoral anteversion. The mean neck-shaft angle was 136° (±5°). The mean maximum alpha location was 2:00 o'clock (±45 minutes) and the mean maximum alpha angle was 52° (±6°). Minimum head-neck offset ratio was located at 1:30 with a mean of 0.14 (±0.03). An anterior head-neck offset ratio of ≤ 0.17 or an alpha angle ≥ 55° was found in 43 (86%) of hips. Twenty-one dysplastic hips (42%) had an alpha angle ≥ 55°. Mildly dysplastic hips had decreased femoral head and neck offset (9 ± 1) and head and neck offset ratio (0.20 ± 0.03) at 12 o'clock compared with moderate/severe dysplastic hips (10 ± 1 and 0.22 ± 0.03, respectively; p = 0.04 and p = 0.01). With the numbers available, we found that hips with excessive femoral anteversion (> 20°) had no difference in the alpha angle at 3 o'clock (42 ± 7) compared with hips with relative femoral retroversion (≤ 5°; 48 ± 4; p = 0.06). No other differences in femoral morphology were found between hips with mild or moderate/severe dysplasia or in the femoral version subgroups with the numbers available. Anterior impingement test was positive in 76% of hips with an alpha angle ≥ 55° and 83% of the hips with an alpha angle ≤ 55°. No correlation was found between proximal femoral morphology and preoperative ROM. CONCLUSIONS: In this subset of dysplastic hips, cam deformity of the femoral head and neck was present in 42% of hips with maximal head-neck deformity at 2 o'clock, and 82% had reduced head-neck offset at the 1:30 point. We conclude that cam-type deformities and decreased head-neck offset in developmental dysplasia of the hip are common. Patients should be closely assessed for need of a head and neck osteochondroplasty, especially after acetabular correction. Future prospective studies should evaluate the influence of proximal femoral anatomy on surgical results of PAO for dysplastic hips. LEVEL OF EVIDENCE: Level IV, prognostic study.

[Operative Treatment for Saddle-Shaped Femoral Heads]. / Operacní resení sedlovité deformity hlavice kosti stehenní.

PURPOSE OF THE STUDY A saddle-shaped deformity of the femoral head has a poor prognosis due to rapid development of secondary changes. A new method of treatment by intra-articular anteromedial wedge reduction osteotomy (AWRO) of the femoral head may preserve the hip for the future. This study was designed to ascertain that this invasive technique was safe and effective and to confirm our hypothesis that AWRO significantly improved functional and radiological parameters of the hip joint. MATERIAL AND METHODS Patients who underwent AWRO between 2010 and 2013 were enrolled in this study. The indication criteria for the procedure included Stulberg grade V hips on AP radiographs, hinged abduction with pain, limping and a limited range of movement. Values of the Stulberg grading, capital diaphyseal index, caput-collum-diaphyseal angle and Harris hip score were recorded before and after surgery and the results were statistically evaluated using the paired t-test. The AWRO procedure was performed from the anterolateral approach after subperiosteal protection of the vessels had been ensured. The central necrotic part of the femoral head was removed, and the medial segment was mobilised and fixed to the intact lateral segment. Either a hip spica cast or bed-rest for six weeks was indicated. Full weight bearing was allowed at 3 months after surgery. RESULTS Twelve patients with an average follow-up of 55 months were evaluated. There were eight boys and four girls with an average age of 14 years at the time of surgery. The average Harris hip score improved from 54.52 before to 73.58 after surgery. The post-operative outcomes according to the Stulberg classification included one grade II hip, seven grade III hips, three grade IV hips and one grade V hip. The average capital-diaphyseal index dropped from 1.56 (1.19-1.92) to 1.28 (0.95-1.67) and the average caput-collum-diaphyseal angle increased from 134 degrees (121-143) to 140 degrees (130-155) after surgery. Avascular necrosis developed in two patients. All the differences were statistically significant. DISCUSSION Reduction osteotomies of the femoral head reported in the literature differ from the AWRO procedure used in this study in both the approach and the performance. The results presented here are in agreement with those published in the relevant literature. They showed no significant deterioration in comparison with the outcomes of our short-term study reported earlier. The outcome of treatment is related to the disease aetiology, functional parameters and previous procedures involving the hip joint. CONCLUSIONS AWRO is a salvage procedure that prolongs the longevity of joints in incongruent hips with very high morbidity. This procedure gave significantly better results in years after surgery, which confirmed our hypothesis. Level of evidence IV Key words: hinge abduction, Perthes disease, Stulberg, femoral head reduction osteotomy, avascular necrosis, arteria circumflexa femoris medialis.