Evaluation of Brace Treatment for Infant Hip Dislocation in a Prospective Cohort

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1 1215 COPYRIGHT Ó 2016 BY THE OURNAL OF BONE AND OINT SURGERY, INCORPORATED Evaluation of Brace Treatment for Infant Hip Dislocation in a Prospective Cohort Defining the Success Rate an Variables Associate with Failure Viyahar V. Upasani, MD, ames D. Bomar, MPH, Travis H. Matheney, MD, Wubhav N. Sankar, MD, Kishore Mulpuri, MBBS, MS(Ortho), MHSc(Epi), Charles T. Price, MD, Colin F. Moseley, MD, CM, FRCS, Simon P. Kelley, MBChB, MRCS, FRCS, Unni Narayanan, MBBS, MSc, FRCS(C), Nicholas M.P. Clarke, ChM, DM, FRCS, ohn H. Wege, OC, MD, FRCSC, Pablo Castañea, MD, ames R. Kasser, MD, Bruce K. Foster, MBBS, MD, FRACS, ose A. Herrera-Soto, MD, Peter. Cuny, MBBS, FRACS, Nicole Williams, FRACS, BMe, BMeSc, an Scott. Mubarak, MD Backgroun: The use of a brace has been shown to be an effective treatment for hip islocation in infants; however, previous stuies of such treatment have been single-center or retrospective. The purpose of the current stuy was to evaluate the success rate for brace use in the treatment of infant hip islocation in an international, multicenter, prospective cohort, an to ientify the variables associate with brace failure. Methos: All islocations were verifie with use of ultrasoun or raiography prior to the initiation of treatment, an patients were followe prospectively for a minimum of 18 months. Successful treatment was efine as the use of a brace that resulte in a clinically an raiographically reuce hip, without surgical intervention. The Mann-Whitney test, chisquare analysis, an Fisher exact test were use to ientify risk factors for brace failure. A multivariate logistic regression moel was use to etermine the probability of brace failure accoring to the risk factors ientifie. Results: Brace treatment was successful in 162 (79%) of the 204 islocate hips in this series. Six variables were foun to be significant risk factors for failure: eveloping femoral nerve palsy uring brace treatment (p = 0.001), treatment with a static brace (p < 0.001), an initially irreucible hip (p < 0.001), treatment initiate after the age of 7 weeks (p = 0.005), a right hip islocation (p = 0.006), an a Graf-IV hip (p = 0.02). Hips with no risk factors ha a 3% probability of failure, whereas hips with 4 or 5 risk factors ha a 100% probability of failure. Conclusions: These ata provie valuable information for patient families an their proviers regaring the important variables that influence successful brace treatment for islocate hips in infants. Level of Evience: Prognostic Level I. See Instructions for Authors for a complete escription of levels of evience. Peer review: This article was reviewe by the Eitor-in-Chief an one Deputy Eitor, an it unerwent bline review by two or more outsie experts. It was also reviewe by an expert in methoology an statistics. The Deputy Eitor reviewe each revision of the article, an it unerwent a final review by the Eitor-in-Chief prior to publication. Final corrections an clarifications occurreuring one or more exchanges between the author(s) an copyeitors. Developmental ysplasia of the hip (DDH) is the most common hip isorer in the peiatric population, with 1% to 3% of all newborns being iagnose at birth 1,2.This iagnosis escribes a wie spectrum of abnormal hip morphology ranging from mil (a reuce femoral hea in a ysplastic acetabulum) to severe (a femoral heaislocate entirely from the acetabulum). The islocate femoral hea might be passively reucible (Ortolani positive) or irreucible (Ortolani negative) as a result of muscle contractures an intra-articular obstructions 3-5. The natural history of an untreate unilateral hip islocation has been stuie 6,7. Most such patients have a poor clinical outcome ue to limb-length inequality, ipsilateral knee eformity an pain, or seconary scoliosis an back pain. However, most patients with DDH can be effectively treate if iagnose at a young age, justifying some form of neonatal screening. While universal neonatal ultrasonography is performe in some European countries, other countries, incluing the Unite States, perform selective screening of infants with Disclosure: REDCap atabase coorination, maintenance, an support was provie by the International Hip Dysplasia Institute ( org). On the Disclosure of Potential Conflicts of Interest forms, which are provie with the online version of the article, one or more of the authors checke yes to inicate that the author ha a relevant financial relationship in the biomeical arena outsie the submitte work an yes to inicate that the author ha other relationships or activities that coul be perceive to influence, or have the potential to influence, what was written in this work. Bone oint Surg Am. 2016;98:

2 1216 TABLE I Demographics Hips Analyze Success Failure Total Hips Lost to Follow-up Age* (ays) At initial visit 34.8 ± ± ± ± 48.7 At initiation of treatment 35.1 ± ± ± ± 48.7 Duration of follow-up* (mo) 28.0 ± ± ± ± 3.9 Gestational age* (wk) 39.4 ± ± ± ± 1.2 Sex Male 35 (21.6) 9 (21.4) 44 (21.6) 5 (9.3) Female 127 (78.4) 33 (78.6) 160 (78.4) 49 (90.7) Fetal presentation Breech 51 (31.5) 19 (45.2) 70 (34.3) 16 (29.6) Cephalic 104 (64.2) 21 (50.0) 125 (61.3) 36 (66.7) Unknown 7 (4.3) 2 (4.8) 9 (4.4) 2 (3.7) Sie of involvement Bilateral 71 (43.8) 19 (45.2) 90 (44.1) 22 (40.7) Left only 60 (37.0) 10 (23.8) 70 (34.3) 25 (46.3) Right only 31 (19.1) 13 (31.0) 44 (21.6) 7 (13.0) Delivery metho Cesarean 78 (48.1) 25 (59.5) 103 (50.5) 31 (57.4) Vaginal 84 (51.9) 17 (40.5) 101 (49.5) 23 (42.6) Immeiate family history Yes 27 (16.7) 11 (26.2) 38 (18.6) 10 (18.5) No 129 (79.6) 27 (64.3) 156 (76.5) 42 (77.8) Unknown 6 (3.7) 4 (9.5) 10 (4.9) 2 (3.7) Swaling history Yes 44 (27.2) 13 (31.0) 57 (27.9) 5 (9.3) No 109 (67.3) 26 (61.9) 135 (66.2) 42 (77.8) Unknown 9 (5.6) 3 (7.1) 12 (5.9) 7 (13.0) *The values are given as the mean an the stanareviation. The values are given as the number of hips, with the percentage in parentheses. risk factors for hip ysplasia (e.g., first-born status, female sex, breech intrauterine position, or a family history of DDH) or when finings on physical examination are consistent with hip instability The primary goals in the treatment of a islocate infant hip are well establishe: (1) to obtain concentric reuction of the joint, (2) to maintain reuction, an (3) to allow for appropriate evelopment of the femoral hea an acetabulum, while (4) avoiing complications such as osteonecrosis of the femoral hea. Treatment with a brace previously has been shown to be a variably effective strategy to successfully manage islocate hips Previous stuies on the Pavlik harness, the mostly wiely use orthosis for DDH in infants, have emonstrate success rates ranging from 58% to 97% Most of these stuies, however, have been retrospective, from a single institution, an without clear ocumentation of the severity of hip islocation prior to initiating brace treatment The goals of the present stuy were to evaluate the success rate of brace treatment for infants with evience of hip islocation in an international, multicenter, prospective cohort, an to ientify the variables associate with brace failure. We hypothesize that brace treatment coul successfully manage the majority of the islocate hips an that specific risk factors coul be ientifie to etermine the probability of brace failure. Materials an Methos Stuy Design Aresearch network for the prospective stuy of DDH was establishe involving 7 institutions across North America, Europe, an Australia. Institutional review boar or ethics committee approval was grante at all sites prior to the initiation of ata collection. Stuy ata were collecte prospectively an manage using REDCap (Research Electronic Data Capture) tools 23. The group stanarize the iagnostic criteria use to ientify the islocate hips; however, each center was allowe to use inepenent treatment protocols as this woul permit the stuy of practice variation an outcomes.

3 1217 TABLE II Univariate Analysis of Outcome of Brace Treatment by Risk Factor* Success Failure P Value Dislocation status <0.001 Reucible 136 (86.6) 21 (13.4) Irreucible 26 (55.3) 21 (44.7) Graf grae <IV 104 (86.0) 17 (14.0) IV 56 (70.0) 24 (30.0) Brace type <0.001 Dynamic 157 (82.6) 33 (17.4) Static 5 (35.7) 9 (64.3) Femoral nerve palsy No 159 (82.8) 33 (17.2) Yes 2 (25.0) 6 (75.0) In-clinic ultrasoun 0.08 Yes 98 (83.8) 19 (16.2) No 64 (73.6) 23 (26.4) Sie 0.02 Left 98 (85.2) 17 (14.8) Right 64 (71.9) 25 (28.1) Age at initial treatment wk 124 (84.9) 22 (15.1) >7 wk 38 (65.5) 20 (34.5) Alpha angle (89.7) 6 (10.3) < (75.5) 35 (24.5) months prior to the initiation of this analysis but i not have 18 months of follow-up an were not seen in the 6 months prior to this analysis. All of the centers trie various strategies to contact the families of patients lost to followup, incluing telephone calls, letters, an electronic messages. Patient Cohort Two hunre an four islocate hips in 159 infants were evaluate. Data Collection Demographic etails, such as ate of birth, maternal age, maternal parity, birth weight, sex, gestational age, fetal presentation, birth metho, family history, an swaling history, were recore at baseline. The results of a clinical examination, incluing an assessment of hip abuction an hip reucibility an stability, an motor an sensory examination, were recore at each visit. Ultrasonographic ata collecte inclue the location of the femoral hea, joint laxity, percentage of coverage of the femoral hea, an assessment of osseous acetabular morphology an the cartilage roof triangle. The alpha angle was evaluate as a categorical variable accoring to our osseous acetabular graes (A = goo, alpha angle of >59 ; B= eficient/ roune, alpha angle of 50 to 59 ; anc= ysplastic, alpha angle of <50 ). Each hip was also grae accoring to the Graf classification 25 ; the islocate hips in this cohort were given a Graf grae of III or IVon the basis of the shape of the osseous acetabulum an the cartilage roof triangle on a static coronal *The values are given as the number of hips, with the percentage of hips for the given category in parentheses. Only hips with complete ata are inclue (n = 201 for Graf grae an alpha angle, an n = 200 for femoral nerve palsy). Inclusion Criteria We enrolle all infants who were <6 months of age an ha a new iagnosis of hip islocation at rest. The hip islocation was verifie with use of ultrasoun or raiography prior to the initiation of treatment. Hips were consiereislocate if the femoral hea was <30% covere on the coronal view on ultrasoun or if they were IHDI (International Hip Dysplasia Institute) grae III or IV on raiographs 24. Patients were followe for at least 18 months, by which time they ha either complete treatment with no evience of requiring further treatment or were treate surgically after failing brace treatment. Nine hips with <18 months of follow-up were inclue because they require surgery prior to 18 months, which was consiere a terminal event. Exclusion Criteria Infants were exclue if they were enrolle in the stuy but their family refuse treatment; if the islocation was associate with a synrome or other congenital hip abnormality; if they ha a miler form of DDH, such as a subluxable or ysplastic hip with no islocation; or if they ha receive previous treatment for DDH. Aitionally, 13 hips were exclue from this analysis because they were initially treate surgically with no attempt at brace treatment (Fig. 1); 8 of the hips were treate with close reuction, an 5 were treate with open reuction. Patients were consiere lost to follow-up if they were enrolle at least 18 Fig. 1 Flow iagram for the stuy cohort. F/u = follow-up, CR = close reuction, an OR = open reuction.

4 1218 TABLE III Ajuste Os of Failure by Risk Factor an Probability of Failure by Number of Risk Factors* Binary Logistic Regression Generalize Estimating Equation Preictive Value OR (95% CI)* P Value OR (95% CI)* P Value Probability of Failure Sensitivity Specificity Positive Negative Risk factor Femoral nerve palsy uring 34.2 ( ) ( ) < % 99% 75% 83% brace treatment Treatment with static 17.8 ( ) < ( ) % 97% 64% 83% brace Irreucibility 6.6 ( ) < ( ) < % 84% 45% 87% Treatment initiate at 4.0 ( ) ( ) % 77% 34% 85% >7 wk of age Right-sie islocation 3.7 ( ) ( ) % 60% 28% 85% Graf-IV grae at presentation 3.3 ( ) ( ) % 65% 30% 86% No. of risk factors 0 3.1% (1 of 32) 2% 81% 3% 76% 1 4.7% (4 of 86) 10% 49% 5% 68% % (19 of 57) 45% 77% 33% 84% 3 50% (11 of 22) 26% 93% 50% 83% 4 100% (5 of 5) 12% 100% 100% 81% 5 100% (2 of 2) 5% 100% 100% 80% *CI = confience interval. image. If the cartilage roof triangle was interpose, the hip was classifie as Graf grae IV. Raiographic ata collecte inclue evaluation of the Shenton line, the acetabular inex, the IHDI grae 24, the state of ossification of the femoral hea, a escription of the tearrop, the lateral center-ege angle, an the presence of osteonecrosis of the femoral hea. Treatment etails, incluing the age at the initiation of treatment, the uration of treatment, the type of brace an the number of hours that brace wear was prescribe, an any surgical intervention or complications, were recore. Static braces, such as the Denis Browne, Von Rosen, an Plastazote braces, were groupe together an compare with treatment with the ynamic Pavlik harness. Primary Outcome Successful treatment was efine as obtaining an maintaining reuction of the hip following bracing with no subsequent surgical treatment. Hip reuction was etermine raiographically using the IHDI graing system 24 on the most recent anteroposterior pelvic raiograph, an clinically base on a stable an unrestricte range of hip abuction on examination. Failure was efine as a hip that i not achieve or maintain reuction of the hip joint at the time of final follow-up after being treate with bracing alone. Seconary Outcomes Seconary outcomes inclue the acetabular inex as a measure of resiual acetabular ysplasia, an complications such as femoral nerve palsy (clinical iagnosis) an osteonecrosis (raiographic). Statistical Analysis Significant ifferences were note between right an left hips in bilateral cases. Forty percent of the bilateral cases iffere between right an left with respect to reucibility an osseous or cartilaginous classifications, an therefore, the hip was use as the unit of analysis to etermine variables associate with our primary outcome. The Shapiro-Wilk test of normality was performe on all continuous ata. The Mann-Whitney test was use to compare ifferences in age at the initiation of treatment between hips that faile brace treatment an those that i not. Chisquare analysis an the Fisher exact test were use to evaluate brace failures on the basis of the reucibility of the hip, the severity of the islocation (Graf grae an alpha angle), bilaterality, brace type (static versus ynamic), the rate of complications, an treatment facility (by iniviual site an as groupe accoring to whether the site ha in-clinic ultrasoun an accoring to volume). Variables associate with our primary outcome at a significance level of p < 0.1 were inclue in a multivariate logistic regression moel to evaluate preictors of brace treatment failure. Ajuste os ratios (ORs) erive from the logistic regression moel were reporte. A multivariate generalize estimating equation (GEE) was use to control for the potential effect of bilateral cases on the moel. A receiver operating characteristic (ROC) curve was constructe to evaluate the accuracy of the risk factors in our moel in their ability to preict brace failure. An analysis of variance (ANOVA) was use to compare ifferences in the acetabular inex at the time of final followup between hips that faile brace treatment an those that i not. No a priori power analysis was performe. All statistics were calculate using SPSS software (version 22; IBM), with significance efine as p < Results Demographics are presente in Table I. The mean age at the initiation of brace treatment (an stanareviation) was 39 ± 36 ays (range, 0 to 163 ays). The mean uration of follow-up was 27 ± 8 months (range, 6 to 49 months). One hunre an sixty-two of the 204 hips were successfully treate with a brace (a 79% success rate). Forty-two hips faile brace treatment an require surgical treatment (a 21% failure rate). The mean age at the initiation of treatment for hips that were successfully treate with a brace was 35 ± 34 ays compare with 54 ± 40 ays for the hips that faile brace treatment (p = 0.006). The average acetabular inex at the time of final followup was 22 ± 4 (range, 11 to 31 ) among the hips successfully treate with a brace an 26 ± 5 (range, 13 to 35 ) among the hips that require surgical treatment (p < 0.001). Ten (5%) of the 204 hips in this cohort were note to have raiographic evience of osteonecrosis of the femoral hea.

5 1219 Fig. 2 Results of brace treatment for infant hip islocation by stuy site. The results of brace treatment by site are presente in Figure 2. Success rates range from 50% to 88% across the 7 centers. One facility (G) ha a significantly higher success rate (88%) compare with that of the other sites combine (74%) (p = 0.02). When treatment facilities were groupe by those that ha in-clinic ultrasoun monitoring (C, D, an G) an those that i not (A, B, E, an F), no significant ifference in brace success was observe (Table II) (p = 0.08). Brace outcomes were not foun to be significantly ifferent at the three highest-volume sites (E, F, an G) compare with the others (A, B, C, an D) (p = 0.119). In the univariate analysis, 8 variables met the significance criteria to be inclue in the multivariate moel (Table II). The proportion of hips that faile treatment i not iffer on the basis of whether the patient ha bilateral or unilateral involvement (p = 0.9) or on the basis of sex (p = 1.0). Six variables were foun to be significant risk factors for failure in the multivariate moel (Table III). A test of the full moel emonstrate significance, inicating that the preictors as a set reliably istinguishe between success an failure of brace treatment (chi square = 72.7; egrees of freeom = 8; p < 0.001). The moel accounte for 30% to 48% of variation. The sensitivity of the moel in preicting failure was 94%, an the specificity was 56%. The probability of brace failure was assesse accoring to the number of risk factors present (Table III). Three percent of the hips with no risk factors went on to fail brace treatment compare with 100% of hips with 4 or 5 risk factors. In constructing an ROC curve, the area uner the curve was foun to be 0.83 (p < 0.001). Loss to Follow-up Forty-three infants with 54 islocate hips (21%) were lost to follow-up uring treatment an were exclue from the analysis (Table I). The mean follow-up for this cohort was 9 ± 4 months (range, 0.9 to 16 months). None of these patients were foun to have osteonecrosis or femoral nerve palsy prior to being lost to follow-up. Discussion This is the first stuy that we know of to assess the success of brace treatment for hip islocation in infants using an international, multicenter, prospective cohort stuy esign. Unlike previous investigations, this stuy inclue a clearly efine prospective cohort of infants with only islocate hips that were either reucible (Ortolani positive) or irreucible (Ortolani negative). All patients ha raiographic or ultrasonographic verification of the hip islocation prior to the initiation of treatment, an patients were followe for at least 18 months. The overall success rate of treatment with a brace for this cohort was 79%. Reucibility of the hip has consistently been shown to be an important variable in brace success In the current cohort, ultrasonography was use to verify whether the femoral hea was reucible or irreucible with the Ortolani maneuver (gentle hip traction, flexion, an abuction) at initial presentation. While a previous stuy recommene abanoning harness treatment for these irreucible islocations 26,weemonstratea55%early success rate among irreucible hips treate with use of a brace. It is important to follow these complicate patients closely with weekly ultrasoun an clinical examinations to ensure that the range of hip abuction is improving an that femoral nerve function is intact, an to assess the position of the femoral hea. Longer follow-up is neee to better unerstan rates of osteonecrosis in these hips. Patient age at the initiation of brace treatment was evaluate as a continuous variable an as a categorical variable. The

6 1220 mean age at the initiation of treatment among the hips that were successfully treate with a brace was significantly less than that among the hips that faile brace treatment (p = 0.006). Atalar et al. evaluate 31 frankly islocate hips in 25 patients ocumente by ynamic ultrasonography 21.Theyfouna significantly higher success rate with bracing if treatment was initiate prior to the age of 7 weeks (p = 0.038). On the basis of their ata, we also use a 7-week cutoff to evaluate our patient cohort an foun a significant ifference between the two groups. In our cohort, hips treate after the age of 49 ays were 4 times more likely to fail brace treatment. This fining emonstrates the importance of appropriate eucation of peiatricians an neonatologists in conucting routine, serial, perinatal hip examinations an of the urgent referral of islocate hips to optimize brace treatment outcomes. It is important to emphasize that these ata support early treatment for only the most severe islocate infant hips, which represent a minority (1% to 5%) of all patients with DDH 27. It is unclear why the sie of the hip islocation was a significant risk factor in the multivariate analysis. As in previous investigations, a majority (56%) of the islocate hips in this cohort were left-sie. It is hypothesize that left-sie islocations are more common because of the left occiput anterior fetal positioning, which causes increase auction of the infant s left hip in utero against the maternal sacrum 28.It coul be that right-sie hip islocations are inherently more severe an thus more ifficult to treat conservatively with a brace. Further analysis of this fining is require to better unerstan its importance. The vast majority (93%) of the hips in this cohort were treate with a Pavlik harness, with an overall success rate of 83%. Conversely, 9 of 14 hips initially treate with a static brace went on to require surgical treatment (a 36% success rate). The brace types were groupe together in the statistical analysis because of the similar mechanism of correction (simple abuction with the static braces versus ynamic flexion an abuction with the Pavlik harness) 14, The inication for using a static abuction brace varie among centers, ranging from stanar practice to family preference. Although the iscrepancy in the sample size of the two groups was substantial, the statistical methos use allowe for appropriate comparison between the two treatment methos. All patients in this cohort who evelope femoral nerve palsy (8 hips) were treate with a Pavlik harness, an the nerve palsy was likely ue to excessive flexion of the hip. The 4% rate of this complication is slightly greater than the previously reporte rate of 2.7% 33. This may be because all patients in our cohort ha more severe DDH, with completely islocate hips, while the previous stuy inclue miler forms of ysplasia 33. Of the 8 hips with femoral nerve palsy, 6 (75%) faile brace treatment an unerwent surgery. This may inicate a selection bias, as brace treatment was iscontinue for these patients for a variable perio of time to allow for recovery of nerve function. However, it may also inicate that these hips were inherently more ifficult to reuce or keep reuce, requiring hyperflexion of the hip in the brace, which may have cause the femoral nerve palsy. Patient age at the initiation of treatment i not seem to play a role; among the 8 hips for which femoral nerve palsy was note, treatment was initiate at an average of 60 ays (range, 12 to 81 ays; meian, 66 ays) for the 6 hips that faile treatment an at 12 ays an 71 ays for the 2 hips that were successfully treate with a brace. There were limitations to this stuy that shoul be aresse. Primarily, 21% of the patients were exclue because they were lost to follow-up, espite our best attempts to contact the families. At the latest follow-up, however, a majority of the hips were reuce an the lost-to-follow-up group appeare to be comparable with the stuy cohort in terms of the success rate of brace treatment. Also, the risk factors ientifie in this stuy were goo preictors of failure in this cohort because we built the moel aroun this ata set; aitional stuies, involving a ifferent cohort, shoul be carrie out to etermine the generalizability of these risk factors as preictors of failure. Aitionally, although the average follow-up for this cohort was more than 2 years, the ultimate success of brace treatment nees to be followe until skeletal maturity to etermine the true rate of femoral hea osteonecrosis an the ultimate nee for surgical treatment. Another limitation was that there was no central ajuication of raiographic an ultrasonographic measurements in this stuy group. In this prospective, international, multicenter cohort stuy, we emonstrate a higher than previously reporte success rate of the Pavlik harness as the initial management of a islocate infant hip (not associate with a synrome or congenital malformation other than DDH). The multivariate analysis ientifie specific risk factors associate with higher failure rates, which, for the firsttimethatweknowof,provietreatingphysiciansexplicit prognostic ata with respect to the success of nonoperative treatment an the likelihoo of requiring subsequent surgical management. Aitional investigation is necessary to eluciate finer etails of the uration of brace wear an when to abanon brace treatment when face with persistent islocation, in orer to maximize success of nonoperative management an minimize complications. n NOTE: The authors thank Emily Schaeffer, PhD, for ata management an analysis. Viyahar V. Upasani, MD 1 ames D. Bomar, MPH 1 Travis H. Matheney, MD 2 Wubhav N. Sankar, MD 3 Kishore Mulpuri, MBBS, MS(Ortho), MHSc(Epi) 4 Charles T. Price, MD 5 Colin F. Moseley, MD, CM, FRCS 6 Simon P. Kelley, MBChB, MRCS, FRCS 7 Unni Narayanan, MBBS, MSc, FRCS(C) 7 Nicholas M.P. Clarke, ChM, DM, FRCS 8 ohn H. Wege, OC, MD, FRCSC 7 Pablo Castañea, MD 9 ames R. Kasser, MD 2 Bruce K. Foster, MBBS, MD, FRACS 10 ose A. Herrera-Soto, MD 5 Peter. Cuny, MBBS, FRACS 10

7 1221 Nicole Williams, FRACS, BMe, BMeSc 10 Scott. Mubarak, MD 1 1 Ray Chilren s Hospital, San Diego, California 2 Boston Chilren s Hospital, Boston, Massachusetts 3 Chilren s Hospital of Philaelphia, Philaelphia, Pennsylvania 4 British Columbia Chilren s Hospital, Vancouver, British Columbia, Canaa 5 Arnol Palmer Hospital for Chilren, Orlano, Floria 6 Hilton Hea Islan, South Carolina 7 Hospital for Sick Chilren, Toronto, Ontario, Canaa 8 University of Southampton, Southampton, Hampshire, Unite Kingom 9 Centro Méico ABC Santa Fe, Mexico City, Tlaxcala, Mexico 10 Department of Orthopaeic Surgery, Women s an Chilren s Hospital, North Aelaie, South Australia, Australia aress for V.V. Upasani: vupasani@rchs.org References 1. Gowar S, Dezateux C; MRC Working Party on Congenital Dislocation of the Hip. Meical Research Council. Surgery for congenital islocation of the hip in the UK as a measure of outcome of screening. Lancet Apr 18;351 (9110): Tibrewal S, Gulati V, Ramachanran M. 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