The Pavlik harness (PH) is commonly used to treat infantile dislocated hips. Variability exists in the duration of brace treatment after successful reduction of the dislocated hip. In this study we evaluate the effect of prescribed time in brace on acetabular index (AI) at two years of age using a prospective, international, multicenter database. We retrospectively studied prospectively enrolled infants with at least one dislocated hip that were initially treated with a PH and had a recorded AI at two-year follow-up. Subjects were treated at one of two institutions. Institution 1 used the PH until they observed normal radiographic acetabular development. Institution 2 followed a structured 12-week brace treatment protocol. Hip dislocation was defined as less than 30% femoral head coverage at rest on the pre-treatment ultrasound or IHDI grade III or IV on the pre-treatment radiograph. Fifty-three hips met our inclusion criteria. Hips from Institution 1 were treated with a brace 3x longer than hips from institution 2 (adjusted mean 8.9±1.3 months vs 2.6±0.2 months)(p < 0 .001). Institution 1 had an 88% success rate and institution 2 had an 85% success rate at achieving hip reduction (p=0.735). At 2-year follow-up, we observed no significant difference in AI between Institution 1 (adjusted mean 25.6±0.9˚) compared to Institution 2 (adjusted mean 23.5±0.8˚) (p=0.1). However, 19% of patients from Institution 1 and 44% of patients from Institution 2 were at or below the 50th percentile of previously published age- and sex- matched AI normal data (p=0.049). Also, 27% (7/26) of hips from Institution 1 had significant acetabular dysplasia, compared to a 22% (6/27) from Institution 2 (p=0.691). We found no correlation between age at initiation of bracing and AI at 2-year follow-up (p=0.071). Our findings suggest that prolonged brace treatment does not result in improved acetabular index at age two years. Hips treated at Institution 1 had the same AI at age two years as hips treated at Institution 2, while spending about 1/3 the amount of time in a brace. We recommend close follow-up for all children treated for dislocated hips, as ~1/4 of infants had acetabular index measurements at or above the 90th percentile of normal. Continued follow-up of this prospective cohort will be critical to determine how many children require acetabular procedures during childhood. The PH brace can successfully treat dislocated infant hips, however, prolonged brace treatment was not found to result in improved acetabular development at two-year follow-up

Introduction. The hip hemiarthroplasty in posterior approach is a common surgical procedure at the femoral neck fractures in the elderly patients. However, the postoperative hip precautions to avoid the risk of dislocations are impeditive for early recovery after surgery. We used MIS posterior approach lately known as conjoined tendon preserving posterior (CPP) approach, considering its enhancement of joint stability, and examined the intraoperative and postoperative complications, retrospectively. Methods. We performed hip hemiarthroplasty using CPP approach in 30 patients, and hip hemiarthroplasty using conventional posterior approach in 30 patients, and both group using lateral position with the conventional posterior skin incision. The conjoined tendon (periformis, obturator internus, and superior/inferior gemellus tendon) was preserved and the obturator externus tendon was incised in CPP approach without any hip precautions postoperatively. The conjoined tendon was incised in conventional approach using hip abduction pillow postoperatively. Results. There was no difference between CPP approach group and conventional approach group in the mean age of patients (81.8 years, and 80.3 years, respectively), and in the mean operative time (68.8 minutes, and 64.9 minutes, respectively). In 4 cases of CPP approach, the avulsion fracture at femoral attachment of the conjoined tendon occured during hip reduction manoeuvres. No dislocations occured in both groups in the follow-up period (2 years). Discussion. Lately, the number of hip surgery in muscle sparing approach is increasing. However, in general, MIS approach induces the intraoperative complications, and requires the skillful procedure. The hip reduction manoeuvres would be more difficult in the CPP approach, than in conventional posterior approach, because the preserved conjoined tendon would inhibit hip reduction, considering those avulsion fractures of the femoral attachment. Nevertheless, CPP approach did not require no extended time compared to conventional approach, and no postoperative hip precautions. Due to these results, CPP approach could be a good MIS procedure including early recovery after surgery based on the enhancement of joint stability, excluding the difficulties in hip reduction manoeuvres. We could not show the difference in dislocation rate between two groups, because of small numbers. We are planning to increase the number of patients in the future study

Purpose. Following closed or open reduction for developmental dysplasia of the hip (DDH), assessment of reduction is essential. With potentially poor accuracy in confirming reduction, the risk of abnormal hip development and ultimately poor outcome exists if reduction is not achieved. Computed tomography (CT) has been used in recent years to assess reduction. The aim of this study was to compare the accuracy in confirming hip reduction following closed or open reduction in children with DDH, using CT and plain radiographs and to decide whether CT scans improved the assessment of reduction. Methods. We retrospectively reviewed 6 patients treated for DDH at an Academic Hospital. The patients were treated with either closed or open reduction. Post operatively radiographs and CT scans were obtained to assess reduction. Reduction was assessed using Shenton's line, medial joint space, a femoral mid-cervical line through the tri-radiate cartilage and a tri-radiate intersectional line on axial CT. The CT scans were analyzed using Osirix on an Apple Macintosh computer. Results. We were able to obtain measurements in all parameters in only one radiograph, whereas in the CT images all parameters were determined. One patient had radiographs in which no values could be measured. The CT scan however confirmed reduction of that hip. In one patient we assessed a hip as reduced using all the parameters, whereas the tri-radiate intersectional line on axial CT and the Shenton's line on the coronal slice showed that in fact the head was posteriorly subluxed. Conclusion. We conclude that although CT scans did not change our management in this small patient series, CT scans did provide a better means of confirming hip reduction than plain radiographs for patients with DDH following closed or open reduction in a hip spica. NO DISCLOSURES

Introduction. The standard plane imaging of Graf and the dynamic methods of Harcke are well established methods in assessing hip dysplasia but give limited information in the flexed-abducted treatment position used in the Pavlik harness. The femoral head may sit on the edge of the acetabulum in a flexed position and only reduce when the hips are abducted. This may mean that hips, which reduce when abducted in the Pavlik harness, appear subluxed when scanned in neutral abduction. Harness treatment may thereby be abandoned prematurely due to the failure to confirm reduction. This study identifies ultrasound landmarks on an anterior hip scan which could be used to confirm reduction of the hip in Pavlik Harness. Materials and method. Hips of a newborn piglet were scanned, imaged with magnetic resonance and x-rayed both before and after anatomical dissection. Radiographic markers delineated the position of the tri-radiate cartilage and potential ultrasound landmarks identified to help confirm hip reduction in the flexed-abducted position. Porcine imaging was then compared with that of a human newborn. Results. The porcine model corresponded well to human imaging and we were able to establish a landmark, the ‘Ischial Limb’, which corresponds to the ossification front delineating the posterior ischial edge of the tri-radiate cartilage. This could clearly be seen on anterior hip ultrasound of both the porcine and human hip. This landmark can be used to confirm the hip is reduced by reference to the centre of the femoral head. Discussion and conclusion. We would recommend anterior hip scanning using the ‘Ischial Limb’ as a reference point to confirm hip reduction in Pavlik harness. This simple method is a useful adjunct to conventional ultrasound scanning in the harness treatment of hip instability

Introduction. Current standard cups of metal on metal resurfacing hip arthroplasty (RHA) have no dome holes and it is very difficult for surgeons to confirm full seating of these cups. This sometimes results in gap formation between the cup and acetabular floor. Although the incidence of initial gaps using modular press-fit cups with dome screw holes has been reported to range from 20 to 35%, few studies have reported the incidence of gap formation with monoblock metal cups and its clinical consequences in RHA. The purpose of this study was to investigate retrospectively the incidence of initial gap formation and whether the initial gap influences the clinical results in RHA. Material and Method. RHA was performed on 166 hips of 146 patients using the Birmingham Hip Resurfacing (BHR) (MMT, UK) between 1998 and 2007. Mean age at operation was 48.7 years (range, 19-85 years). Mean duration of follow-up was 6.9 years (2.0-10.6). Acetabular reaming was performed with the use of hemispherical reamers and the reamer size was increased up to an odd number diameter which provided tight rim fit in the antero-posterior direction. The same size hemispherical provisional cup with dome holes and slits was used to check the cavity for complete seating. If the provisional cup could not be seated on the floor, reaming was repeated with the same reamer to remove the rim bump until full seating was achieved. Acetabular cups of 1mm larger diameter were impacted into the acetabulum by a press-fit technique. After press-fit fixation, the stability of the cups was confirmed with a synchronized movement of the pelvis and the cup inserter by applying a gentle torque. Clinical evaluation was performed using WOMAC at the latest follow-up. Radiographic assessments were performed using radiographs immediately after the surgery, at 3 weeks, 3 months, 1 year, and then annually thereafter. We evaluated the height of the gap between the cup and acetabular surface, cup inclination angle, cup migration and the time to gap filling. To investigate the relationship between the magnitude of the gap and the radiographic results, the patients were divided into two groups according to the height of the initial gap; the cases with a gap of less than 3 mm on the initial radiograph were grouped into a small gap group, the cases with a gap of 3mm or more were grouped into a large gap group. We compared the changes in the height of the gap, in the cup inclination angle and the cup migration between the groups. Results. Gaps were identified in 21 of 166 hips (13%) on the postoperative radiograph. The average height of the gaps was 2.4 mm (0.56-4.5mm). Of the 21 hips with gaps, there was no revision during the follow up period. 12 of the 21 hips were classified into the small gap group, 9 of the 21 hips were classified into the large gap group. In the small gap group, there were no changes of cup inclination angle of more than 3 degrees nor was there cup migration of more than 3mm. On the other hand, in the large gap group, 6 of the 9 hips showed reductions of the cup inclination angle of more than 3 degrees with 3mm or more of migration during the initial 3 months (P<0.05). After 3 months, neither progressive angle change nor migration of the cup were observed. All acetabular components were judged to be bone ingrown at the last follow up. Conclusions. The incidence of initial postoperative gaps (13%) of this series is similar to that of modular cementless cups fixed with press-fit technique. There were no serious clinical consequences of the initial gap during the 6.9 year follow up. However, gaps of 3mm or more led to early migration of the acetabular component and change in inclination angle