Aims. Reimers migration percentage (MP) is a key measure to inform decision-making around the management of hip displacement in cerebral palsy (CP). The aim of this study is to assess validity and inter- and intra-rater reliability of a novel method of measuring MP using a smart phone app (HipScreen (HS) app). Methods. A total of 20 pelvis radiographs (40 hips) were used to measure MP by using the HS app. Measurements were performed by five different members of the multidisciplinary team, with varying levels of expertise in MP measurement. The same measurements were repeated two weeks later. A senior orthopaedic surgeon measured the MP on picture archiving and communication system (PACS) as the gold standard and repeated the measurements using HS app. Pearson’s correlation coefficient (r) was used to compare PACS measurements and all HS app measurements and assess validity. Intraclass correlation coefficient (ICC) was used to assess intra- and inter-rater reliability. Results. All HS app measurements (from 5 raters at week 0 and week 2 and PACS rater) showed highly significant correlation with the PACS measurements (p < 0.001). Pearson’s correlation coefficient (r) was constantly over 0.9, suggesting high validity. Correlation of all HS app measures from different raters to each other was significant with r > 0.874 and p < 0.001, which also confirms high validity. Both inter- and intra-rater reliability were excellent with ICC > 0.9. In a 95% confidence interval for repeated measurements, the deviation of each specific measurement was less than 4% MP for single measurer and 5% for different measurers. Conclusion. The HS app provides a valid method to measure hip MP in CP, with excellent inter- and intra-rater reliability across different medical and allied health specialties. This can be used in hip surveillance programmes by interdisciplinary measurers. Cite this article: Bone Jt Open 2023;4(5):363–369

Aims. Given the possible radiation damage and inaccuracy of radiological investigations, particularly in children, ultrasound and superb microvascular imaging (SMI) may offer alternative methods of evaluating new bone formation when limb lengthening is undertaken in paediatric patients. The aim of this study was to assess the use of ultrasound combined with SMI in monitoring new bone formation during limb lengthening in children. Methods. In this retrospective cohort study, ultrasound and radiograph examinations were performed every two weeks in 30 paediatric patients undergoing limb lengthening. Ultrasound was used to monitor new bone formation. The number of vertical vessels and the blood flow resistance index were compared with those from plain radiographs. Results. We categorized the new bone formation into three stages: stage I (early lengthening), in which there was no obvious callus formation on radiographs and ultrasound; stage II (lengthening), in which radiographs showed low-density callus formation with uneven distribution and three sub-stages could be identified on ultrasound: in Ia punctate callus was visible; in IIb there was linear callus formation which was not yet connected and in IIc there was continuous linear callus. In stage III (healing), the bone ends had united, the periosteum was intact, and the callus had disappeared, as confirmed on radiographs, indicating healed bone. A progressive increase in the number of vertical vessels was noted in the early stages, peaking during stages IIb and IIc, followed by a gradual decline (p < 0.001). Delayed healing involved patients with a prolonged stage IIa or those who regressed to stage IIa from stages IIb or IIc during lengthening. Conclusion. We found that the formation of new bone in paediatric patients undergoing limb lengthening could be reliably evaluated using ultrasound when combined with the radiological findings. This combination enabled an improved assessment of the prognosis, and adjustments to the lengthening protocol. While SMI offered additional insights into angiogenesis within the new bone, its role primarily contributed to the understanding of the microvascular environment rather than directly informing adjustments of treatment. Cite this article: Bone Joint J 2024;106-B(7):751–758

Aims. The diagnosis of developmental dysplasia of the hip (DDH) is challenging owing to extensive variation in paediatric pelvic anatomy. Artificial intelligence (AI) may represent an effective diagnostic tool for DDH. Here, we aimed to develop an anteroposterior pelvic radiograph deep learning system for diagnosing DDH in children and analyze the feasibility of its application. Methods. In total, 10,219 anteroposterior pelvic radiographs were retrospectively collected from April 2014 to December 2018. Clinicians labelled each radiograph using a uniform standard method. Radiographs were grouped according to age and into ‘dislocation’ (dislocation and subluxation) and ‘non-dislocation’ (normal cases and those with dysplasia of the acetabulum) groups based on clinical diagnosis. The deep learning system was trained and optimized using 9,081 radiographs; 1,138 test radiographs were then used to compare the diagnoses made by deep learning system and clinicians. The accuracy of the deep learning system was determined using a receiver operating characteristic curve, and the consistency of acetabular index measurements was evaluated using Bland-Altman plots. Results. In all, 1,138 patients (242 males; 896 females; mean age 1.5 years (SD 1.79; 0 to 10) were included in this study. The area under the receiver operating characteristic curve, sensitivity, and specificity of the deep learning system for diagnosing hip dislocation were 0.975, 276/289 (95.5%), and 1,978/1,987 (99.5%), respectively. Compared with clinical diagnoses, the Bland-Altman 95% limits of agreement for acetabular index, as determined by the deep learning system from the radiographs of non-dislocated and dislocated hips, were -3.27° - 2.94° and -7.36° - 5.36°, respectively (p < 0.001). Conclusion. The deep learning system was highly consistent, more convenient, and more effective for diagnosing DDH compared with clinician-led diagnoses. Deep learning systems should be considered for analysis of anteroposterior pelvic radiographs when diagnosing DDH. The deep learning system will improve the current artificially complicated screening referral process. Cite this article: Bone Joint J 2020;102-B(11):1574–1581

Aims. To describe and analyze the mid-term functional outcomes of a large series of patients who underwent the Hoffer procedure for brachial plexus birth palsy (BPBP). Methods. All patients who underwent the Hoffer procedure with minimum two-year follow-up were retrospectively reviewed. Active shoulder range of movement (ROM), aggregate modified Mallet classification scores, Hospital for Sick Children Active Movement Scale (AMS) scores, and/or Toronto Test Scores were used to assess functional outcomes. Subgroup analysis based on age and level of injury was performed. Risk factors for subsequent humeral derotational osteotomy and other complications were also assessed. A total of 107 patients, average age 3.9 years (1.6 to 13) and 59% female, were included in the study with mean 68 months (24 to 194) follow-up. Results. All patients demonstrated statistically significant improvement in all functional outcomes and active shoulder abduction and external rotation ROM (p < 0.001). Patients < 2.5 years of age had higher postoperative AMS, abduction ROM and strength scores, and aggregate postoperative Toronto scores (p ≤ 0.035) compared to patients ≥ 2.5 years old. There were 17 patients (16%) who required a subsequent humeral derotational osteotomy; lower preoperative AMS external rotation scores and external rotation ROM were predictive risk factors (p ≤ 0.016). Conclusion. Patients with BPBP who underwent the Hoffer procedure demonstrated significant improvement in postoperative ROM, strength, and functional outcome scores at mid-term follow-up. Patients younger than 2.5 years at the time of surgery generally had better functional outcomes. Limited preoperative external rotation strength and ROM were significantly associated with requirement for subsequent humeral derotational osteotomy. In our chort significant improvements in shoulder function were obtained after the Hoffer procedure for BPBP. Cite this article: Bone Joint J 2020;102-B(2):246–253

Aims. The health-related quality of life (HRQoL) of paediatric patients with orthopaedic conditions and spinal deformity is important, but existing generic tools have their shortcomings. We aim to evaluate the use of Paediatric Quality of Life Inventory (PedsQL) 4.0 generic core scales in the paediatric population with specific comparisons between those with spinal and limb pathologies, and to explore the feasibility of using PedsQL for studying scoliosis patients’ HRQoL. Methods. Paediatric patients attending a speciality outpatient clinic were recruited through consecutive sampling. Two groups of patients were included: idiopathic scoliosis, and paediatric orthopaedic upper and lower limb condition without scoliosis. Patients were asked to complete PedsQL 4.0 generic core scales, Youth version of 5-level EuroQol-5-dimension questionnaire, and Refined Scoliosis Research Society 22-item (SRS-22r) questionnaire. Statistical analyses included scores comparison between scoliosis and limb pathology patients using independent-samples t-test, and correlation tests of PedsQL and SRS-22r. Results. A total of 566 paediatric patients were recruited: 357 (63.0%) having idiopathic scoliosis, and 209 (37.0%) with limb conditions. Patients with limb pathology had lower functioning scale, summary, and total scores of PedsQL than scoliosis patients (p < 0.05 to p < 0.001). No floor or ceiling effects (< 15%) were detected for PedsQL Psychosocial Health Summary and total scores in both groups. PedsQL was sensitive in differentiating patients with/without problems in their daily lives (p < 0.05 to p < 0.01). PedsQL summary and total scores correlated with SRS-22r total score. Conclusion. PedsQL is an effective HRQoL measure for both paediatric orthopaedic groups with minimal ceiling and floor effects, and is capable of detecting worse HRQoL in patients with limb pathology. The multidimensional PedsQL is sensitive in differentiating among those with daily life problems, especially for scoliosis patients. Cite this article: Bone Joint J 2020;102-B(7):890–898

Aims. The aim of this study was to report the clinical, functional and radiological outcomes of children and adolescents with tibial fractures treated using the Ilizarov method. Patients and Methods. Between 2013 and 2016 a total of 74 children with 75 tibial fractures underwent treatment at our major trauma centre using an Ilizarov frame. Demographic and clinical information from a prospective database was supplemented by routine functional and psychological assessment and a retrospective review of the notes and radiographs. Results. Of the 75 fractures, 26 (35%) were open injuries, of which six (8%) had segmental bone loss. There were associated physeal injuries in 18 (24%), and 12 (16%) involved conversion of treatment following failure of previous management. The remaining children had a closed unstable fracture or significant soft-tissue compromise. The median follow-up was 16 months (7 to 31). All fractures united with a median duration in a frame of 3.6 months (interquartile range 3.1 to 4.6); there was no significant difference between the types of fracture and the demographics of the patients. There were no serious complications and no secondary procedures were required to achieve union. Health-related quality of life measures were available for 60 patients (80%) at a minimum of six months after removal of the frame. These indicated a good return to function (median Paediatric quality of life score, 88.0; interquartile range 70.3 to 100). Conclusion. The Ilizarov method is a safe, effective and reliable method for the treatment of complex paediatric tibial fractures. Cite this article: Bone Joint J 2018;100-B:396–403

Aims. We report the use of the distal radius and ulna (DRU) classification for the prediction of peak growth (PG) and growth cessation (GC) in 777 patients with idiopathic scoliosis. We compare this classification with other commonly used parameters of maturity. Patients and Methods. The following data were extracted from the patients’ records and radiographs: chronological age, body height (BH), arm span (AS), date of menarche, Risser sign, DRU grade and status of the phalangeal and metacarpal physes. The mean rates of growth were recorded according to each parameter of maturity. PG was defined as the summit of the curve and GC as the plateau in deceleration of growth. The rates of growth at PG and GC were used for analysis using receiver operating characteristic (ROC) curves to determine the strength and cutoff values of the parameters of growth. Results. The most specific grades for PG using the DRU classification were radial grade 6 and ulnar grade 5, and for GC were radial grade 9 and ulnar grade 7. The DRU classification spanned both PG and GC, enabling better prediction of these clinically relevant stages than other methods. The rate of PG (≥ 0.7 cm/month) and GC (≤ 0.15 cm/month) was the same for girls and boys, in BH and AS measurements. Conclusion. This is the first study to note that the DRU classification can predict both PG and GC, providing evidence that it may aid the management of patients with idiopathic scoliosis. Cite this article: Bone Joint J 2016;98-B:1689–96

Aims. The Ponseti method is an effective evidence-based treatment for clubfoot. It uses gentle manipulation to adjust the position of the foot in serial treatments towards a more physiological position. Casting is used to hold the newly achieved position. At first, the foot resists the new position imposed by the plaster cast, pressing against the cast, but over time the tissues are expected to adapt to the new position and the force decreases. The aim of this study was to test this hypothesis by measuring the forces between a clubfoot and the cast during treatment with the Ponseti method. Patients and Methods. Force measurements were made during the treatment of ten idiopathic clubfeet. The mean age of the patients was seven days (2 to 30); there were nine boys and one girl. Force data were collected for several weeks at the location of the first metatarsal and the talar neck to determine the adaptation rate of the clubfoot. Results. In all measurements, the force decreased over time. The median (interquartile range) half-life time was determined to be at 26 minutes (20 to 53) for the first metatarsal and 22 minutes (9 to 56) for the talar neck, suggesting that the tissues of the clubfoot adapt to the new position within several hours. Conclusion. This is the first study to provide objective force data that support the hypothesis of adaptation of the idiopathic clubfoot to the new position imposed by the cast. We showed that the expected decrease in corrective force over time does indeed exist and adaptation occurs after a relatively short period of time. The rapid reduction in the forces acting on the foot during treatment with the Ponseti method may allow significant reductions in the interval between treatments compared with the generally accepted period of one week

Aims. Using 90% of final height as a benchmark, we sought to develop a quick, quantitative and reproducible method of estimating skeletal maturity based on topographical changes in the distal femoral physis. Patients and Methods. Serial radiographs of the distal femoral physis three years prior to, during, and two years following the chronological age associated with 90% of final height were analyzed in 81 healthy children. The distance from the tip of the central peak of the distal femoral physis to a line drawn across the physis was normalized to the physeal width. Results. A total of 389 radiographs of the distal femur with corresponding Greulich and Pyle bone ages and known chronological ages were measured. Children reached 90% of final height at a mean age of 11.3 years (. sd. 0.8) for girls and 13.2 years (. sd. 0.6) for boys. Linear regression analysis showed higher correlation coefficent in predicting the true age at 90% of final height using chronological age + gender + central peak value (R. 2 . = 0.900) than chronological age + gender (R. 2.  = 0.879) and Greulich and Pyle bone age + gender (R. 2.  = 0.878). Conclusion. Chronological age + gender + central peak value provides more accurate prediction of 90% of final height compared with chronological age + gender and Greulich and Pyle bone age + gender. Cite this article: Bone Joint J 2018;100-B:1106–11

Aims. This pilot study aimed to evaluate prospectively the use of inlet radiographs of the hip as an alternative method of the assessment of reduction after the surgical treatment of developmental dysplasia of the hip (DDH). Patients and Methods. The children in this study underwent surgery between January 2013 and January 2015. All had inlet radiographs and CT scans post-operatively. Data were analysed by determining inter-observer reliability and intra-observer reproducibility, using the kappa value (K). Differences were settled by discussion between the two observers until a consensus was reached. The sensitivity and specificity of the radiographic and CT results were compared. A total of 26 radiographs were obtained from 23 children, with a mean age of 2.38 years (one to five). Results. Similar high levels of intra- and inter-observer agreement were observed (K = 0.834, 95% confidence interval (CI)). There was a high agreement between the radiographic and CT results (K = 0.834, 5% CI), with excellent sensitivity and a specificity of 95.5%. Conclusion. These results suggest that inlet radiographs may be a reliable method of assessing the reduction of the hip after the surgical treatment of DDH. Cite this article: Bone Joint J 2017;99-B:697–701

Aims. Our aim was to assess the effectiveness of a protocol involving a standardised closed reduction for the treatment of children with developmental dysplasia of the hip (DDH) in maintaining reduction and to report the mid-term results. Methods. A total of 133 hips in 120 children aged less than two years who underwent closed reduction, with a minimum follow-up of five years or until subsequent surgery, were included in the study. The protocol defines the criteria for an acceptable reduction and the indications for a concomitant soft-tissue release. All children were immobilised in a short- leg cast for three months. Arthrograms were undertaken at the time of closed reduction and six weeks later. Follow-up radiographs were taken at six months and one, two and five years later and at the latest follow-up. The Tönnis grade, acetabular index, Severin grade and signs of osteonecrosis were recorded. Results. A total of 67 hips (51%) were Tönnis grade 3/4 hips. By 12 months, 20 reductions (15%) had not been maintained, and these required open reduction. In all, 55% of these were Severin 1; the others were Severin 2, due to minor acetabular dysplasia. Of the 113 successful closed reductions, 98 hips (87%) were Severin 1. Surgery for residual DDH was offered for ten hips. Osteonecrosis was seen in 32 hips (29%) but was transient in 28. In total, two children (1.5%) had severe osteonecrosis. Bilateral dislocations were significantly more likely to fail and most Tönnis 4 hips failed. Conclusion. Closed reduction, with concomitant adductor and psoas release when required and the use of a short leg plaster of Paris cast for three months, can produce good mid-term results in children with DDH aged less than two years. This protocol is not recommended for Tönnis 4 hips. Cite this article: Bone Joint J 2016;98-B:1548–53

Aims. This study analysed the clinical and radiological outcome of anatomical reduction of a moderate or severe stable slipped capital femoral epiphysis (SCFE) treated by subcapital osteotomy (a modified Dunn osteotomy) through the surgical approach described by Ganz. . Patients and Methods. We prospectively studied 31 patients (32 hips; 16 females and five males; mean age 14.3 years) with SCFE. On the Southwick classification, ten were of moderate severity (head-shaft angle > 30° to 60°) and 22 were severe (head-shaft angle > 60°). Each underwent open reduction and internal fixation using an intracapsular osteotomy through the physeal growth plate after safe surgical hip dislocation. Unlike the conventional procedure, 25 hips did not need an osteotomy of the apophysis of the great trochanter and were managed using an extended retinacular posterior flap. . Results. Clinical outcome was assessed using the range of movement and the Harris Hip (HHS), Western Ontario and McMaster Universities Osteoarthritis (WOMAC), and Merle d’Aubigné scores, while radiological measurements included slip and alpha angles. The mean duration of follow-up was 24.1 months (12 to 40). . There was a significant improvement in all clinical and radiological measurements after treatment (p < 0.001). Post-operative major complications were one deep infection and one case of femoral head collapse. . Conclusion. These findings suggest that a modified Dunn osteotomy carried out through Ganz approach is a safe and effective method of treating the stable SCFE with a high degree of slip. . Cite this article: Bone Joint J 2016;98-B:1283–8

Aims. It is well established that there is a strong association between Perthes’ disease and worsening socioeconomic deprivation. It has been suggested that the primary determinant driving this association is exposure to tobacco smoke. This study aimed to examine this hypothesis. Patients and Methods. A hospital case-control study (n = 149/146) examined the association between tobacco smoke exposure and Perthes’ disease, adjusting for area-level socioeconomic deprivation. Tobacco smoke exposure was assessed by parental questionnaire of smoking habits during pregnancy, and by quantitative assay of current exposure using the urinary cotinine-creatinine ratio, which is a widely used and validated measure of tobacco smoke exposure. Results. The odds of Perthes’ disease significantly increased with reported in utero exposure after adjustment for socioeconomic deprivation (maternal smoking odds ratio (OR) 2.06, 95% confidence interval (CI) 1.17 to 3.63; paternal smoking OR 2.09, 95% CI 1.26 to 3.46). The cotinine-creatinine ratio was significantly greater in cases, OR 1.63 (95% CI 1.09 to 2.43), suggesting a greater ‘dose’ of current tobacco exposure. Conclusion. An association exists between tobacco smoke exposure and Perthes’ disease but we remain unable to disentangle the association with socioeconomic deprivation. Cite this article: Bone Joint J 2017;99-B:1102–8

We report our initial experience of using the Ponseti method for the treatment of congenital idiopathic club foot. Between November 2002 and November 2004 we treated 100 feet in 66 children by this method. The standard protocol described by Ponseti was used except that, when necessary, percutaneous tenotomy of tendo Achillis were performed under general anaesthesia in the operating theatre and not under local anaesthesia in the out-patient department. The Pirani score was used for assessment and the mean follow-up time was 18 months (6 to 30). The results were also assessed in terms of the number of casts applied, the need for tenotomy of tendo Achillis and recurrence of the deformity. Tenotomy was required in 85 of the 100 feet. There was a failure to respond to the initial regimen in four feet which then required extensive soft-tissue release. Of the 96 feet which responded to initial casting, 31 (32%) had a recurrence, 16 of which were successfully treated by repeat casting and/or tenotomy and/or transfer of the tendon of tibialis anterior. The remaining 15 required extensive soft-tissue release. Poor compliance with the foot-abduction orthoses (Denis Browne splint) was thought to be the main cause of failure in these patients

A retrospective study was performed in 100 children aged between two and 16 years, with a dorsally angulated stable fracture of the distal radius or forearm, who were treated with manipulation in the emergency department (ED) using intranasal diamorphine and 50% oxygen and nitrous oxide. Pre- and post-manipulation radiographs, the final radiographs and the clinical notes were reviewed. A successful reduction was achieved in 90 fractures (90%) and only three children (3%) required remanipulation and Kirschner wire fixation or internal fixation. The use of Entonox and intranasal diamorphine is safe and effective for the closed reduction of a stable paediatric fracture of the distal radius and forearm in the ED. . By facilitating discharge on the same day, there is a substantial cost benefit to families and the NHS and we recommend this method. Take home message: Simple easily reducible fractures of the distal radius and forearm in children can be successfully and safely treated in the ED using this approach, thus avoiding theatre admission and costly hospital stay. . Cite this article: Bone Joint J 2016;97-B:131–6

We report the outcome of 28 patients with spina bifida who between 1989 and 2006 underwent 43 lower extremity deformity corrections using the Ilizarov technique. The indications were a flexion deformity of the knee in 13 limbs, tibial rotational deformity in 11 and foot deformity in 19. The mean age at operation was 12.3 years (5.2 to 20.6). Patients had a mean of 1.6 previous operations (0 to 5) on the affected limb. The mean duration of treatment with a frame was 9.4 weeks (3 to 26) and the mean follow-up was 4.4 years (1 to 9). There were 12 problems (27.9%), five obstacles (11.6%) and 13 complications (30.2%) in the 43 procedures. Further operations were needed in seven patients. Three knees had significant recurrence of deformity. Two tibiae required further surgery for recurrence. All feet were plantigrade and braceable. We conclude that the Ilizarov technique offers a refreshing approach to the complex lower-limb deformity in spina bifida

This study compares the initial outcomes of minimally invasive techniques for single-event multi-level surgery with conventional single-event multi-level surgery. The minimally invasive techniques included derotation osteotomies using closed corticotomy and fixation with titanium elastic nails and percutaneous lengthening of muscles where possible. A prospective cohort study of two matched groups was undertaken. Ten children with diplegic cerebral palsy with a mean age of ten years six months (7.11 to 13.9) had multi-level minimally invasive surgery and were matched for ambulatory level and compared with ten children with a mean age of 11 years four months (7.9 to 14.4) who had conventional single-event multi-level surgery. Gait kinematics, the Gillette Gait Index, isometric muscle strength and gross motor function were assessed before and 12 months after operation. The minimally invasive group had significantly reduced operation time and blood loss with a significantly improved time to mobilisation. There were no complications intra-operatively or during hospitalisation in either group. There was significant improvement in gait kinematics and the Gillette Gait Index in both groups with no difference between them. There was a trend to improved muscle strength in the multi-level group. There was no significant difference in gross motor function between the groups. We consider that minimally invasive single-event multi-level surgery can be achieved safely and effectively with significant advantages over conventional techniques in children with diplegic cerebral palsy

We have evaluated the effect of the use of ultrasound in determining the initiation of treatment in neonatal instability of the hip. A total of 99 newborn infants (1.5% of all live births) with neonatal hip instability did not have treatment from birth, but were re-examined at eight to 15 days. In the 31 who had persisting clinical instability and ultrasound abnormality, treatment was then started with a Frejka pillow. The hips in the remaining 68 infants showed spontaneous clinical stabilisation and improvement of the ultrasound findings. Treatment was therefore withheld. There was a marked trend towards normal development in mildly unstable hips, whereas no hips with severe instability did so spontaneously. Further follow-up showed normal development in all the hips which had been treated, and in all except five of the 68 untreated infants. These five infants showed persistent hip dysplasia on both ultrasound and radiological examination at four to five months of age. Treatment with an abduction splint was then started and their hips developed normally. Ultrasound is very useful in deciding on treatment if the examiners have adequate experience with the method. Its use substantially reduces the rate of treatment. Spontaneous resolution occurred in more than half of the unstable hips. Since five of the untreated infants developed hip dysplasia a strict follow-up is essential to identify and treat these cases

We reviewed the medical records of 115 patients with 130 hips with developmental dysplasia with complete dislocation in the absence of a neuromuscular disorder, spontaneous reduction with a Pavlik harness, and a minimum of 14 years’ follow-up. The mean age at the time of harness application was 4.8 months (1 to 12) and the mean time spent in the harness was 6.1 months (3 to 12). A total of 108 hips (83.1%) were treated with the harness alone and supplementary surgery for residual acetabular dysplasia, as defined by an acetabular index > 30°, was performed in 22 hips (16.9%).

An overall satisfactory outcome (Severin grade I or II) was achieved in 119 hips (91.5%) at a mean follow-up of 16 years (14 to 32) with a follow-up rate of 75%. Avascular necrosis of the femoral head was noted in 16 hips (12.3%), seven of which (44%) underwent supplementary surgery and nine (56%) of which were classified as satisfactory. The acetabular index was the most reliable predictor of residual acetabular dysplasia.

In a prospective study, 232 neonates were examined sonographically using the methods of Graf and Terjesen. In order to determine the reproducibility of the methods, 50 hips were evaluated by two skilled examiners. In an inter-observer study, five physicians and five medical students evaluated 24 images, which were evaluated on ten occasions at two-weekly intervals by one of the authors. Statistical evaluation used the Bland-Altman approach. The neonates (110 females, 122 males) were less than four days old. The mean α angle was 62.4° and mean femoral head cover was 55.4%. According to Graf’s method, 1.3% of hips were pathological, compared with 4.1% according to Terjesen. Spearman’s correlation coefficient between femoral head cover and α angles was 0.552. The Bland-Altman approach shows greater variation for femoral head cover than for α, if measured by experienced examiners. The Bland-Altman approach shows almost equal reproducibility for α and femoral head cover in the inter-observer test, but better repeatability for α in the intra-observer test. The Graf results relate better than Terjesen’s to the well-known frequency of 1% to 2% hip dysplasia in the European population. Kappa statistics indicate a fair agreement between the two methods. Inter-observer evaluation shows an equal reproducibility of both methods, whereas intra-observer tests reveal better repeatability with Graf’s method