Bilateral synovitis in symptomatic unilateral transient synovitis of the hip: An ultrasonographic study in 56 children

56 children with a clinical diagnosis of unilateral transient synovitis of the hip underwent bilateral sonographic assessment. On the anterior scan, the distance between the femoral neck and the fibrous joint capsule was measured. This distance, which we call the synovial capsular complex distance, was compared with age-dependent normal values. An in-creased distance was found in all 56 symptomatic hips (mean 10 mm, SD 1.8). This distance was also increased in 14 hips on the contralateral side (mean 8 mm, SD 1.6). An effusion was demonstrated in 53 symptomatic hips and in 8 hips on the contralateral side. These findings indicate that in one quarter of children with symptoms of unilateral transient synovitis the contralateral hip may have an increased synovial capsular complex distance due to synovial swelling or joint effusion, suggesting an asymptomatic synovitis. We therefore recommend a comparison of the synovial capsular complex distance on the symptomatic side with age-related normal values, in addition to a comparison with the asymptomatic hip.     

Ultrasonography in hip disease in children

Intra-articular synovial effusion was visualized in different juvenile hip diseases by ultrasonography; 166 hips from 149 children were examined. Joint aspiration of 97 hips confirmed that ultrasonography was more sensitive than conventional radiography in diagnosing effusion. The magnitude of the ultrasonic joint space correlated well with the clinical severity of the disease, the volume of synovial fluid, and the intra-articular pressure. Considerable widening of the ultrasonic joint space was seen in transient synovitis, septic arthritis, reactive arthritis and arthritis with urticaria; moderate widening was seen in some patients with Perthes disease, and symmetrical joint space in patients with nonspecific arthralgia. We conclude that ultrasonography is valuable in the diagnosis and follow-up of synovial effusion of the hip in children.     

Ultrasonography in hip disease in children

Intra-articular synovial effusion was visualized in different juvenile hip diseases by ultrasonography; 166 hips from 149 children were examined. Joint aspiration of 97 hips confirmed that ultrasonography was more sensitive than conventional radiography in diagnosing effusion. The magnitude of the ultrasonic joint space correlated well with the clinical severity of the disease, the volume of synovial fluid, and the intra-articular pressure. Considerable widening of the ultrasonic joint space was seen in transient synovitis, septic arthritis, reactive arthritis and arthritis with urticaria; moderate widening was seen in some patients with Perthes disease, and symmetrical joint space in patients with nonspecific arthralgia. We conclude that ultrasonography is valuable in the diagnosis and follow-up of synovial effusion of the hip in children.     

Ultrasound in the diagnosis and follow-up of transient synovitis of the hip

Of 59 patients (2-15 years of age) with acute synovitis of the hip, one patient developed Perthes disease (1.7%) and the others transient synovitis. The diagnostic criterion for intracapsular effusion was a side difference greater than or equal to 2.0 mm in the distance between the anterior joint capsule and the femoral neck (anterior capsule distance, ACD). At the time of admission, the mean ACD of the affected and unaffected hips was 8.2 and 4.2 mm, respectively. The effusion persisted for greater than 1 week in 58% of the patients. We recommend ultrasound as the main imaging technique in the diagnosis and follow-up of transient synovitis. Radiography may be omitted in uncomplicated cases, but should be employed when Perthes disease is suspected.     

Mechanoreceptor evaluation of hip joint capsule and ligamentum capitis femoris in developmental hip dysplasia: a preliminary study

We aimed to determine if there are mechanoreceptors in the hip joint capsule and ligamentum capitis femoris (LCF) of patients with developmental dysplasia of the hip (DDH). We took capsule and LCF biopsies from 20 hips of 20 patients who were operated on because of DDH. The mean age was 10.2 months (range 6-20 months) at the time of surgery. There were 12 girls and eight boys. Teratologic and secondary hip dislocations were not included in this study. Full thickness, 0.5 x 0.5 cm anterior capsule and LCF portions were taken for biopsy specimen. Specimens were stained with hemotoxylin eosin and examined immunohistochemically using monoclonal antibody against S-100 protein. In both analyses no mechanoreceptor was found in any samples of capsule or LCF. In this preliminary study we could not find mechanoreceptors in the local anterior joint capsule and LCF of the hip in children with DDH. We think that additional studies are necessary in order to understand the mechanoreceptor characteristics of the hip joint in children not only with DDH but also in children with healthy hips.     

Ultrasonography in transient synovitis and early Perthes' disease

We used ultrasonography to examine 36 children suffering from transient synovitis and 12 children with early Perthes' disease. Widening of the joint space was revealed by ultrasonography in all affected hips with either disease. In the patients with transient synovitis, capsular distension was attributed to synovial effusion, while in the patients with Perthes' disease it was produced by thickening of the synovial membrane. Neither capsular distension nor thickening of the joint cartilage was seen in the contralateral normal hip in the patients with transient synovitis, but they were common in early Perthes' disease. Ultrasonography may provide significant diagnostic clues to differentiate early Perthes' from transient synovitis.     

Ultrasonography for diagnosis of slipped capital femoral epiphysis. Comparison with radiography in 9 cases.

In 7 of 8 patients with non-acute slipped capital femoral epiphysis, the slip was visualized by ultrasound. The mean epiphyseal displacement was 6.0 mm, measured on an anterior ultrasound scan. Grading of slip severity by ultrasound was consistent with the radiographic assessment. Two patients had a moderate hip joint effusion which did not affect the final outcome, whereas one patient with an acute slip had a pronounced effusion, and necrosis of the epiphysis occurred. The anteversion angles of the affected hips were reduced as compared to those of the normal hips. It was concluded that ultrasonography was reliable in detecting pronounced and mild degrees of epiphyseal slips, whereas minimal slips could be missed. The detection of hip effusion is important because a tamponade may cause vascular impairment of the epiphysis, unless aspirated.     

Ultrasonography for diagnosis of slipped capital femoral epiphysis

In 7 of 8 patients with non-acute slipped capital femoral epiphysis, the slip was visualized by ultrasound. The mean epiphyseal displacement was 6.0 mm, measured on an anterior ultrasound scan. Grading of slip severity by ultrasound was consistent with the radiographic assessment. Two patients had a moderate hip joint effusion which did not affect the final outcome, whereas one patient with an acute slip had a pronounced effusion, and necrosis of the epiphysis occurred. The anteversion angles of the affected hips were reduced as compared to those of the normal hips. It was concluded that ultrasonography was reliable in detecting pronounced and mild degrees of epiphyseal slips, whereas minimal slips could be missed. The detection of hip effusion is important because a tamponade may cause vascular impairment of the epiphysis, unless aspirated.     

Hip Joint Instability After the Neonatal Period: Diagnosis and Treatment of 20 Consecutive Cases

A consecutive series of 20 children (21 hips) with idiopathic hip joint instability, diagnosed after the neonatal period, is presented. The diagnosis was confirmed by hip joint arthrography. In all the children, 1.5-21 months old at the time of diagnosis, closed reduction could be achieved. They were treated in plaster directly or after treatment of contractures in the adductor muscles of the hip joint.

Stability was rapidly attained during plaster treatment.

The results of the treatment in plaster were checked by a second arthrography in two thirds of the cases, and all cases have been clinically and radiologically evaluated 1-4.5 years after diagnosis. All of the children developed clinically stable hips and they walk normally. In two hips signs of avascular necrosis of the femoral head were found and in three hips (two children) the skeletal development was markedly delayed. In 81 per cent (17/21 hips) the prognosis was considered good; it is uncertain in the remaining four hips.

The appropriate period of fixation in plaster related to the age of the child is discussed.     

Is Ranawat triangle method accurate in estimating hip joint center in Japanese population?

BackgroundLittle information has been available regarding the usefulness of Ranawat triangle method in estimating anatomical hip joint center in the Japanese population. In this study, we aimed to determine the accuracy of the method in estimating hip joint center.MethodsUsing digitally reconstructed radiographs of 123 normal hips (123 patients), we measured the hip joint center coordinates (Cx, Cy) with reference to the ipsilateral lowest point of the teardrop, the pelvic width, and the pelvic height. Using these measurement values, we performed the following analyses: (1) the relationship of hip joint center location with pelvic dimensions; (2) accuracy of Ranawat method in estimating hip joint center; (3) alternative methods to estimate hip joint center using pelvic height.ResultsThe mean Cx and Cy were 32 ± 3.0 mm and 13 ± 2.1 mm, respectively. Pelvic height was positively correlated with Cx (r = 0.51, p < 0.001) and Cy (r = 0.69, p < 0.001), but the correlations of pelvic width with Cx and Cy were negligible. The mean estimation error of the Ranawat method was ?6.7 ± 2.6 mm in x-axis and 6.6 ± 1.9 mm in y-axis, respectively. The hip joint center was estimated within a 5 mm error in both axes in only 8 hips (6.5%). Thus, we developed two estimating methods using pelvic height, modified Ranawat method and pelvic height ratio method, and the estimation errors of these methods were within 5 mm in both axes in 118 hips (96%) and 116 hips (94%), respectively.ConclusionsRanawat method showed poor accuracy in estimating anatomical hip joint center and is not recommended for clinical use. Our alternative methods may be useful for surgeons planning the position of the acetabular component in total hip arthroplasty.     

The radiographic joint space width in clinically normal hips: effects of age,gender and physical parameters

OBJECTIVE: The aim of the study was to assess the relationship of the radiographic joint space width (JSW) in the hip with age and a variety of physical parameters in a clinically non-arthritic population in order to identify potential age-related changes. DESIGN: One hundred and eighteen patients (58F/60M, age range 20-79 years) who underwent supine abdominal radiography for non-rheumatological indications and had no hip pain were evaluated. Height, weight and leg lengths were measured. JSW was quantified manually by a dial caliper, and femoral head diameters were determined for each hip. RESULTS: Overall, JSW was 3.61mm+/-0.58 (mean+/-SD) in the right (R) and 3.63mm+/-0.59 in the left (L) hip (range 2.34-6.1mm). There was no age-related decline in the JSW, either by decade (P=0.5 and 0.6, for R and L hips, respectively), or by individual age (Spearman's rho=-0.108 and 0.057, P=0.3 and 0.5 for R and L hips, respectively); similarly, no age-related changes were observed when each gender was analyzed separately. Women had significantly narrower hip JSW than men (P=0.001 and 0.01, R and L hips, respectively). However, gender was no longer significant after height was taken into account (P=0.26 and 0.45, for R and L hips, respectively). JSW correlated significantly with height, weight (which also correlated with height) (r=0.31/0.27 and 0.29/0.28 for height and weight R/L, respectively, P<0.004 for each), but not with body mass index (P=0.62 and 0.57, R and L, respectively). Hip JSW significantly correlated also with femoral head diameter and leg length (r=0.38/0.29 and 0.25/0.19 for femoral head and leg length, R/L, respectively). CONCLUSIONS: No effect of aging was detected on the radiographic JSW of the hip among normal individuals even at advanced ages. In contrast, height, femoral head diameter and leg length were directly related to JSW.     

Crowe Ⅱ/Ⅲ型发育性髋关节发育不良股骨近端形态学变化及其对全髋关节置换术的意义

目的分析CroweⅡ/Ⅲ型发育性髋关节发育不良股骨近端的形态变化及其对全髋关节置换术的影响。方法将14例（15髋,CroweⅡ型9髋,CroweⅢ型6髋）成人CroweⅡ/Ⅲ型发育性髋关节发育不良继发骨性关节炎患侧股骨设为治疗组,男2例,女12例;年龄35～61岁。所有患者均未行矫形治疗。15例（15髋）单侧发育性髋关节发育不良患者的健侧股骨为对照组,男3例,女12例;年龄35～57岁。其中12例为治疗组单侧脱位,3例为单侧CroweⅠ型髋关节发育不良。对股骨进行CT扫描,测量股骨头高度（height of centre of femoral head,HCFH）、峡部位置（isthmus position,IP）、颈干角（neck-shaft angle,NS）、股骨前倾角和髓腔闪烁指数及髓腔宽度等参数,并进行统计学分析。结果治疗组和对照组的HCFH分别为50.1±6.7mm和50.1±7.4mm,IP分别为107.4±21.5mm和108.7±18.1mm,比较差异均无统计学意义（P〉0.05）。NS分别为138.3±10.0°和126.7±5.7°,前倾角分别为36.5±15.9°和18.8±5.4°,髓腔闪烁指数分别为4.47±0.40和5.01±0.43,两组比较差异有统计学意义（P〈0.05）。髓腔宽度方面,治疗组在小转子中点上2cm和小转子中点下4cm的内外侧和前后侧宽度均较对照组变小,比较差异有统计学意义（P〈0.05）;两组在峡部水平的髓腔宽度比较差异无统计学意义（P〉0.05）。结论行CroweⅡ/Ⅲ型发育性髋关节发育不良全髋关节置换术时,术前应评估股骨近端的形态学变化,选择直型较小号的股骨假体,术中放置股骨假体于合适的前倾位置。     

Is Increased Acetabular Cartilage or Fossa Size Associated With Pincer Femoroacetabular Impingement?

Background

Surgical treatment for pincer femoroacetabular impingement (FAI) of the hip remains controversial, between trimming the prominent acetabular rim and reverse periacetabular osteotomy (PAO) that reorients the acetabulum. However, rim trimming may decrease articular surface size to a critical threshold where increased joint contact forces lead to joint degeneration. Therefore, knowledge of how much acetabular articular cartilage is available for resection is important when evaluating between the two surgical options. In addition, it remains unclear whether the acetabulum rim in pincer FAI is a prominent rim because of increased cartilage size or increased fossa size.

Questions/purposes

We used reformatted MR and CT data to establish linear length dimensions of the lunate cartilage and cotyloid fossa in normal, dysplastic, and deep acetabula.

Methods

We reviewed the last 200 hips undergoing PAO, reverse PAO, and surgical dislocation for acetabular rim trimming at one institution. We compared MR images of symptomatic hips with acetabular dysplasia (20 hips), pincer FAI (29 hips), and CT scans of asymptomatic hips from patients who underwent CT scans for reasons other than hip pain (20 hips). These hips were chosen sequentially from the underlying pool of 200 potential subjects to identify the first 10 male and the first 10 female hips in each group that met inclusion criteria. As a result of low numbers, we included all hips that had undergone reverse PAO and met inclusion criteria. Cartilage width was measured medially from the cotyloid fossa to the lateral labrochondral junction. Cotyloid fossa linear height was measured from superior to inferior and cotyloid fossa width was measured from anterior to posterior. Superior lunate cartilage width (SLCW) and cotyloid fossa height (CFH) were measured on MR and CT oblique coronal reformats; anterior lunate cartilage width (ALCW), posterior lunate cartilage width (PLCW), and cotyloid fossa width (CFW) were measured on MR and CT oblique axial reformats. Cohorts were compared using multivariate analysis of variance with Bonferroni’s adjustment for multiple comparisons.

Results

Compared with control acetabula, dysplastic acetabula had smaller SLCW (2.08 ± 0.29 mm versus 2.63 ± 0.42 mm, mean difference = ?0.55 mm; 95% confidence interval [CI] = ?0.83 to ?0.27; p < 0.01), ALCW (1.20 ± 0.34 mm versus 1.64 ± 0.21 mm, mean difference = ?0.44 mm; 95% CI = ?0.70 to ?0.18; p = 0.00), CFH (2.84 ± 0.37 mm versus 3.42 ± 0.57 mm, mean difference = ?0.59 mm; 95% CI = ?0.96 to ?0.21; p < 0.01), and CFW (1.98 ± 0.50 mm versus 2.77 ± 0.33 mm, mean difference = ?0.80 mm; 95% CI = ?1.16 to ?0.42; p < 0.0001). Based on the results, we identified two subtypes of deep acetabula. Compared with controls, deep subtype 1 had normal CFH and CFW but increased ALCW (2.09 ± 0.42 mm versus 1.64 ± 0.21 mm; p < 0.001) and PLCW (2.32 ± 0.36 mm versus 2.00 ± 0.32 mm; p = 0.04). Compared with controls, deep subtype 2 had increased CFH (4.37 ± 0.51 mm versus 3.42 ± 0.57 mm; p < 0.01) and CFW (2.76 ± 0.54 mm versus 2.77 ± 0.33 mm; p = 1.0) but smaller SCLW (2.12 ± 0.40 mm versus 2.63 ± 0.42 mm; p < 0.01).

Conclusions

Deep acetabula have two distinct morphologies: subtype 1 with increased anterior and posterior cartilage lengths and subtype 2 with a larger fossa in height and width and smaller superior cartilage length.

Clinical Relevance

In patients with deep subtype 1 hips that have increased anterior and posterior cartilage widths, rim trimming to create an articular surface of normal size may be reasonable. However, for patients with deep subtype 2 hips that have large fossas but do not have increased cartilage widths, we propose that a reverse PAO that reorients yet preserves the size of the articular surface may be more promising. However, these theories will need to be validated in well-controlled clinical studies.

     

The role of pelvic magnetic resonance in evaluating nonhip sources of infection in children with acute nontraumatic hip pain

We retrospectively identified all children with acute hip pain who underwent pelvic magnetic resonance (MR). Children with septic hip or history of trauma were excluded; the remaining children with signs of infection (fever, >38 degrees C; leukocytosis, >12 x 10(9)/L; or elevated erythrocyte sedimentation rate [ESR], >30 mm/h) comprised the study group. Thirty-three children (9 girls; age, 0.8-15.8 years) were identified. On MR examination, 18 (55%) of 33 children had hip joint effusion, whereas 19 (58%) of 33 children had other abnormalities, including pyomyositis (n=15), osteomyelitis (n=12), and sacroiliitis (n=3). Staphylococcus aureus was cultured from 13 (68%) of these 19 children. Compared with MR, sensitivity for bone and soft tissue abnormalities was 30% for pelvic radiography (n=26) and 71% for bone scintigraphy (n=8). Elevated ESR (>30 mm/h) was the clinical finding that best predicted pelvic osteomyelitis or pyomyositis. Pelvic MR should be performed to rule out pelvic osteomyelitis or pyomyositis in children with acute hip pain, ESR of more than 30 mm/h, and no evidence of septic hip.     

Operative treatment of bilateral hip dislocation in children with arthrogryposis multiplex congenita

PURPOSE: Arthrogryposis multiplex congenita (AMC) is a rare syndrome with multiple joint contractures. It is commonly believed that bilaterally dislocated hips associated with joint contractures should not be reduced, because movement is satisfactory, while open reduction leads to poor results. This report presents our experience with surgical management of bilateral dislocation of hips in children with AMC. METHODS: During the period 1990 to 2000, we performed open reduction on 8 hips of 4 children with AMC. The mean age at surgery was 23 months (range, 5-48 months). Open reduction and capsular plication without any bony procedure were performed in 4 hips (2 patients). De-rotation and varus osteotomy of the femur was performed in 4 hips, and Salter osteotomy of the innominate bone in 2 hips. The average acetabular index was 44 degrees, and the mean centreedge angle was -41 degrees preoperatively. RESULTS: The average follow-up period was 4 years (range, 2-9 years). The average acetabular index and centre-edge angle were 19 and 18 degrees, respectively at the time of last follow-up. All children could walk without support. One child required re-opening for redislocation of hip joint. The clinical results were good in 6 hips and fair in 2 hips, according to Severin's and McKay's classifications. CONCLUSION: Our experience shows that open reduction for bilateral dislocation of hips in children with AMC is a suitable option with generally good results. Surgery performed at earlier age gives the best functional outcome.     

Long-term results after open reduction of developmental hip dislocation by an anterior approach lateral and medial of the iliopsoas muscle

The technique of and especially the approach to open reduction of developmental dislocation of the hip are still a matter of discussion. The anterior approach, first lateral and then medial to the iliopsoas muscle, was described by Tonnis in 1978. A follow-up investigation to adulthood has now been performed. Eighty-seven children (118 hips) out of 105 children (83%) who underwent open reduction of developmental dislocation of the hip before the age of 4 years were reinvestigated 10-21 years after the operation. An anterior approach first lateral, then medial to the iliopsoas muscle was chosen, because this offers the best access to the joint. Additional operations including transiliac osteotomy for acetabuloplasty, shortening osteotomy, and femoral osteotomies were performed as necessary. In 92 (78%) of the 118 hips studied the CE angle exceeded 25 degrees and in 98 hips (83%) the VCA angle exceeded 25 degrees. Critical CE angles between 20 and 25 degrees were found in 14% of the hips, and critical VCA angles in 4%. Residual dysplasia (<20 degrees) was found in 8 and 13% of the hips, respectively. Avascular necrosis according to Hirohashi was observed after operation in grade 1 in 5.9% and grade 2 in 1.7%. No necrosis was found following shortening osteotomy of the proximal femur. The anterior approach, first lateral, then medial to the iliopsoas muscle, offers an optimal access to the medial parts of the joint with control of reduction, protects the vasculature of the femoral neck, and allows simultaneous postero-lateral capsulorrhaphy and pelvic osteotomies.     

Treatment of early septic arthritis of the hip in children: comparison of results of open arthrotomy versus arthroscopic drainage

Purpose  The goal of this study was to compare results of open arthrotomy versus arthroscopic drainage in treating septic arthritis of the hip in children. Methods  This prospective controlled study was conducted on twenty patients (20 hips) with acute septic arthritis of the hip. Diagnosis was suspected if there was: a history of fever, non-weight-bearing on the affected limb, erythrocyte sedimentation rate (ESR) of at least 40 mm/h, and white blood cell count of more than 12,000 cells per cubic millimeter. Diagnosis was established by ultrasonographic examination of the affected hip followed by ultrasound-guided aspiration of the joint. Patients were allocated to have either open arthrotomy or arthroscopic drainage of the joint. There were ten patients (ten hips) in each treatment group. The mean age of the patients was 7.3 years in the arthrotomy group, and 8 years in the arthroscopy group. The mean temperatures for the arthrotomy and arthroscopy groups were 38.8 and 38.7°C, respectively. All the children were unable to bear weight on the affected limb. Results   Staphylococcus aureus was the most common causative microorganism in both groups. The mean duration of the children’s hospital stay was 6.4 days in the arthrotomy group and 3.8 days in the arthroscopy group. The difference was highly significant. Infection could be eradicated in all patients of both groups. At the latest follow-up, seven children in the arthrotomy group (70%) had excellent results and three children (30%) had good results. In the arthroscopy group, nine children (90%) had excellent results and one child (10%) had good results. The difference was not statistically significant. Conclusions  Arthroscopic drainage is an effective method in treating septic arthritis of the hip. It is a minimal invasive procedure which is associated with less hospital stay. Arthroscopic drainage of septic arthritis of the hip in children is a valid alternative procedure in early uncomplicated cases and for orthopedic surgeons skilled in pediatric arthroscopy.     

Subchondral cysts arise in the anterior acetabulum in dysplastic osteoarthritic hips

The distribution of subchondral cysts in 57 dysplastic osteoarthritic hips of 38 patients was assessed by computed tomography and by a new computerized technique. The cyst count in osteoarthritic hips was inversely correlated with the width of the joint space. A greater accumulation of cysts was found in the acetabulum than in the femoral head, and more cysts were found in the anterior part of the hip than in the posterior part. Osteoarthritic change was more predominant in the acetabulum than in the femoral head, and was more predominant in the anterior part of the hip than in the posterior part.     

Intracapsular pressure in transient synovitis of the hip

Fourteen consecutive children with symptoms of transient synovitis of the hip were examined with sonography regarding intracapsular effusion, with scintimetry regarding blood-flow in the proximal femoral epiphysis (PFE) and with intracapsular pressure recording and aspiration. All patients had an intracapsular effusion. Intracapsular pressure was found to depend on the position of the hip. The mean pressure with hips in extension and inward rotation was 22.6 kPa (170 mm Hg) whereas in 45 of flexion it was 2.3 kPa. In two cases scintimetry demonstrated reduced blood flow to the PFE; after aspiration, isotope uptake returned to normal, indicating that increased intracapsular pressure has a harmful effect on circulation to the PFE.

Children with transient synovitis should be treated with the hips in 45 of flexion to reduce intracapsular pressure. Forcing the hip in extension causes a risk of ischaemia of the PFE.     

The Salter innominate osteotomy: should it be combined with concurrent open reduction?

The timing of surgical realignment of the acetabulum after reduction of the dysplastic hip is controversial since a delay in correction may allow the joint to sublux again. The radiographic outcome after 188 Salter osteotomies was reviewed 5-25 years postoperatively using a comprehensive rating scale; 139 hips (69%) developed satisfactorily, 49 hips (26%) remained dysplastic but stable and nine hips (5%) were unsatisfactory. The best results occurred in children under the age of 30 months treated by combined open reduction and Salter osteotomy, when no further operation was required. The staged procedure yielded a slightly smaller proportion of satisfactory results, which were independent of the age of the child (and the incidence of redisplacement and avascular change was reduced). If the innominate osteotomy reduced the acetabular inclination by approximately 15 degrees the hip joint usually stabilized and a normal acetabular (Sharp) angle was present at maturity. When 132 patients were assessed clinically at maturity (between the ages of 16 and 35 years), clinical, functional and radiographic review revealed that 121 of 148 hips were graded in Severin groups I and II. The clinical outcome was determined by the degree to which the acetabular dysplasia was corrected.