Ultrasound-guided gradual reduction using flexion and abduction continuous traction for developmental dysplasia of the hip

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1 K. Fukiage, T. Futami, Y. Ogi, Y. Harada, F. Shimozono, N. Kashiwagi, T. Takase, S. Suzuki From Shiga Medical Center for Children, Japan K. Fukiage, MD, PhD, Paediatric Orthopaedic Surgeon T. Futami, MD, Paediatric Y. Ogi, MD, Paediatric Y. Harada, MD, Paediatric F. Shimozono, MD, Paediatric Shiga Medical Center For Children, , Moriyama, Moriyama-city, Shiga Pref., , Japan. N. Kashiwagi, MD, Paediatric SKY Orthopaedic Clinic, 10-1, Futaba-cho, Ibaraki, Osaka, Japan T. Takase, MD, PhD, Paediatric Orthopaedic Surgeon Takase Orthopaedic Clinic, 7-3, Misasagikamigobyono-cho, Yamashina, Kyoto, Japan. S. Suzuki, MD, PhD, Paediatric Orthopaedic Surgeon Mizuno memorial hospital, , Nishiarai, Adachiku, Tokyo, Japan. Correspondence should be sent to Dr K. Fukiage; The British Editorial Society of Bone & Joint Surgery doi: / x.97b $2.00 Bone Joint J 2015;97-B: Received 21 April 2014; Accepted after revision 02 December 2014 CHILDREN S ORTHOPAEDICS Ultrasound-guided gradual reduction using flexion and abduction continuous traction for developmental dysplasia of the hip A NEW METHOD OF TREATMENT We describe our experience in the reduction of dislocation of the hip secondary to developmental dysplasia using ultrasound-guided gradual reduction using flexion and abduction continuous traction (FACT-R). During a period of 13 years we treated 208 Suzuki type B or C complete dislocations of the hip in 202 children with a mean age of four months (0 to 11). The mean follow-up was 9.1 years (five to 16). The rate of reduction was 99.0%. There were no recurrent dislocations, and the rate of avascular necrosis of the femoral head was 1.0%. The rate of secondary surgery for residual acetabular dysplasia was 19.2%, and this was significantly higher in those children in whom the initial treatment was delayed or if other previous treatments had failed (p = ). The duration of FACT-R was significantly longer in severe dislocations (p = 0.001) or if previous treatments had failed (p = 0.018). This new method of treatment is effective and safe in these difficult cases and offers outcomes comparable to or better than those of standard methods. Cite this article: Bone Joint J 2015;97-B: The goal of treatment in developmental dysplasia of the hip (DDH) is concentric reduction of the femoral head with minimal complications. In children with complete dislocation, the results are less favourable and there is a higher rate of avascular necrosis of the femoral head (AVN). The reported incidence of AVN following management in a Pavlik harness is relatively low, at between 3.1% and 16%. 1-3 Following acute reduction under general anaesthesia, however, the incidence is at least 20%, 4,5 and this may increase with surgical reduction. 6,7 A lower rate of AVN following gradual reduction has been reported Suzuki et al 11 classified DDH into three groups according to the findings on ultrasound examination: subluxation (type A), mild dislocation (type B) and severe dislocation (type C). In type B the dislocated femoral head maintains contact with the posterior margin of the acetabulum, with its centre at or anterior to the posterior margin. In type C, the femoral head is completely displaced out of the acetabulum. Following management in a Pavlik harness these authors reported that all type A subluxations reduced with no complications. The rate of reduction for children with a type B dislocation was 78% (18 of 23 hips) and the rate of AVN rate was > 30%. Type C hips were irreducible. Suzuki 12 described the sequence of reduction of dislocated hips using a Pavlik harness as assessed by ultrasound. In type B hips, passive abduction in deep sleep caused the dislocated femoral head to reduce spontaneously. It is thought, however, that this sudden reduction may temporarily increase intra-articular pressure and cause AVN. 13 We therefore developed a new technique to reduce the dislocated femoral head gradually under ultrasound guidance using longitudinal and transverse traction. Since 1993 we have treated all complete dislocations of the hip except for teratologic and neuromuscular dislocations using this method. In this paper we describe in detail our protocol of ultrasound-giuded gradual reduction using flexion and abduction continuous traction (FACT-R). We report our rate of reduction and the rate of complications, including AVN and residual acetabular dysplasia, up to a minimum age of five years. We also describe the risk factors for these complications. Patients and Methods This retrospective study was approved by the local medical ethics committee and covers the period between January 1993 and December 2006, during which time all babies who visited our institution with complete dislocation of the hip were treated using FACT-R. We entered all details into our FACT-R database. We included VOL. 97-B, No. 3, MARCH

2 406 K. FUKIAGE, T. FUTAMI, Y. OGI, Y. HARADA, F. SHIMOZONO, N. KASHIWAGI, T. TAKASE, S. SUZUKI Fig. 1a Fig. 1b Typical axial MRI scans of a) left-type B DDH in flexion (upper) and in flexion and abduction (middle) and anteroposterior radiographs (lower). The white arrow indicates the dislocated femoral head, and the double arrow indicates the reduced femoral head; and b) left type C DDH in flexion (upper) and in flexion and abduction (middle) and anteroposterior radiographs (lower). The white arrows indicate the dislocated femoral head. all babies aged < 12 months who presented with Suzuki type B or C dislocations, and included tertiary referrals and those who had failed initial treatment elsewhere. We excluded 20 patients who were aged < five years at their most recent follow-up. This is the age by when the need for a secondary procedure is determined by four paediatric orthopaedic surgeons (TF, NK, TT and SS). 14 We also excluded children with teratological and neuromuscular dislocations. Our final cohort included 208 dislocated hips in 202 children with a mean follow-up of nine years and one month (five years to 16 years and five months). There were 22 boys and 180 girls with a mean age of four months (0 to 11) at presentation. One baby had a history of failed closed reduction in another hospital, and 43 had had failed treatment with a Pavlik harness elsewhere. In three children the harness had been removed within two weeks, but in 40 it had been maintained for > two weeks. The diagnosis of DDH was established after physical examination by one of four paediatric orthopaedic surgeons (TF, NK, TT and SS). We recorded the findings of the Ortolani test. 15 Radiological confirmation was achieved using anterior axial ultrasound examination in both flexion and abduction. All hips was graded as Suzuki type B or C on ultrasound examination. 16 There were 97 type B dislocations with a positive Ortolani sign, and 40 type B dislocations with a negative Ortolani sign. The Ortolani sign was negative in the 71 type C hips. The hip was further assessed by MRI after hospitalisation, including T 1 -weighted, T 2 -weighted and two-dimensional multiple-echo data image combination (2D-MEDIC) (Fig. 1). 17 Plain radiographs during traction were used to measure distance a, which is the length between the mid-point of the proximal metaphyseal border of the femur and Hilgenreiner s line. 18 The primary outcome measure was concentric reduction of the femoral head. During treatment, we recorded the duration of each step of the protocol and complications, including skin problems. The rate of secondary surgery was assessed. In severe residual dysplasia secondary surgery was performed at the age of four years. Otherwise, the indication for secondary surgery was usually determined by the age of six years. 19 All follow-up radiographs were assessed for the presence of AVN by five authors (KF, TF, YO, YH and FS) as part of this study, and were graded according to the Kalamchi and MacEwen classification. 20 FACT-R protocol FACT-R consists of five steps. We do not recommend starting treatment until the child is at least two months old. The first step of longitudinal traction reduces the proximal cephalad displacement and is continued until distance a is > 8 mm and the range of flexion of the hip is > 90º. A limited range of flexion interferes with step 2. The second step involves indirect lateral skin traction to release the contracture of the adductor muscles and deliver the femoral head from behind the acetabulum. The first and second steps are the preparation for step 3, the essential period in FACT-R when the reduction is achieved and the weight of traction reduced. Step 4 maintains reduction in a hip spica cast, which, in step 5, is converted to a Pavlik harness or abduction brace. THE BONE & JOINT JOURNAL

3 ULTRASOUND-GUIDED GRADUAL REDUCTION USING FLEXION AND ABDUCTION CONTINUOUS TRACTION Fig. 2a 407 Fig. 2b Fig. 2c Photographs showing a) FACT-R during step 1. The weights and the suppression band were applied to prevent the child slipping, b) FACT-R during step 2 and c) FACT-R during step 3. Arrows indicate paddings that lift the greater trochanter. The children are kept in hospital during the first three steps but are allowed overnight or for weekend leave during the first and second steps if indicated. This is because traction is difficult to manage at home. Traction is removed at least twice a day during the first two steps for skin-care purposes. Step 1: longitudinal indirect skin traction is performed with the hip in 20 of flexion and the knee extended. The whole limb is bandaged (Fig. 2). In the first week a 1.5 kg weight is applied, which is gradually increased according to the child s body weight. In some cases we find it is best to increase the weight during deep night-time sleep. The weight is reduced if there are skin problems such as redness or blistering. The effect of traction is estimated using plain radiographs under traction. If distance a is > 8 mm, we proceed to step 2.21 Otherwise, the weight is increased and weekly radiographs are repeated until distance a becomes > 8 mm. Step 2: 1.5 kg of traction in abduction and flexion is applied to each bandaged thigh, ensuring that the angle of abduction does not exceed the limitation of abduction in flexion (Fig. 2). The angle is then increased according to the daily assessment of the range of movement. A Pavlik harness is also used sometimes to maintain flexion of the hip, taking care to prevent spontaneous accidental reduction and AVN. The position of the femoral head is checked by ultrasound on an anterior axial view and when the dislocated head can be manually moved without difficulty to the concentric position, we progress to step 3. In type B dislocations, the concentric reduction sometimes occurs spontaneously. VOL. 97-B, No. 3, MARCH 2015 Step 3: padding is placed under the greater trochanter to lift the dislocated head anteriorly in order to maintain the concentric position. (Fig. 2c). Ultrasound is used to assess the concentricity (Fig. 3) and to select the appropriate position and size of padding. Once optimal concentricity is identified, the weight of traction is reduced by 0.5 kg per day to maintain the femoral head in the acetabulum. In step 4, as the child is now accustomed to the flexed and abducted position, spica casting is usually performed without sedation. Immobilisation in the cast continues for a minimum of four weeks, with biweekly ultrasound examinations to confirm reduction. There is usually considerable soft-tissue interposition after the application of the spica (Fig. 4a) and the spica is maintained until the interposition has resolved. This usually takes less than four weeks, although in some severe type C dislocations it takes six weeks or more (Figs 4b and 4c). Step 5: the Pavlik harness is applied for twice as long as the duration of casting. If the children are able to stand, a fixed abduction brace in the human position is used. Statistical analysis. All data were analysed using Excel 2010 (Microsoft, Redmond, California). Statistical analysis was performed by the unpaired t-test, and p < 0.05 was considered significant. Receiver operating characteristic curve analysis was used to analyse the cut-off value of the risk factor for secondary surgery. Results Duration of treatment. The mean duration of each step is shown in Tables I and II. In children without previous treatment, the time spent in traction was significantly longer at

4 408 K. FUKIAGE, T. FUTAMI, Y. OGI, Y. HARADA, F. SHIMOZONO, N. KASHIWAGI, T. TAKASE, S. SUZUKI Fig. 3b Fig. 3a Typical ultrasound images of a) left-type C DDH during FACT-R (upper) and its scheme (lower). The reduced but not concentric femoral head just before step 3 under 1.5 kg traction. FH, femoral head; A, acetabulum; SP, symphysis pubis and b) left DDH during FACT-R (upper) and its scheme (lower). The femoral head was brought into the acetabulum by reducing the weight to 0.5 kg during step 3. FH, femoral head; A, acetabulum; SP, symphysis pubis. Fig. 4b Fig. 4a Fig. 4c MRI scans showing (a) the clinical course of decreasing soft tissue interposition in typical type C DDH. Axial MRI scan of a typical type C DDH just after application of a spica. White arrow indicates the hip joint space. (b) The clinical course of decreasing soft tissue interposition in typical type C DDH. Axial MRI scan of a typical type C DDH four weeks after casting. The white arrow indicates the hip joint space. (c) The clinical course of decreasing soft tissue interposition in typical type C DDH. Axial MRI scan of a typical type C DDH six weeks after application of a spica. The white arrow indicates the hip joint space. each step for type C dislocations than for type B dislocations (step 1, p < 0.001; step 2, p = 0.003; total duration, p < 0.001). In children with previously treated type B dislo- cations the total duration of traction and the duration of step 2 were both significantly longer than in those without previous treatment, although there was no statistical THE BONE & JOINT JOURNAL

5 ULTRASOUND-GUIDED GRADUAL REDUCTION USING FLEXION AND ABDUCTION CONTINUOUS TRACTION 409 Table I. Duration of treatment for FACT-R. p-values were assessed for the mean duration of steps 1 and 2, and the mean total duration of all steps. Type Previous failed treatment No. hips Mean age (mths; range) Mean duration of step 1 (days; range) Mean duration of step 2 (days; range) Mean total duration of all steps (days; range) B (0 to 10) 16.0 (7 to 69) 6.6 (2 to 40) 26.9 (12 to 78) B (3 to 6) 19.5 (8 to 47) 12.0 (4 to 33) 34.9 (17 to 81) C (2 to 11) 25.9 (8 to 76) 10.4 (2 to 40) 40.8 (22 to 90) C (3 to 10) 28.3 (9 to 62) 22.6 (4 to 94) 55.6 (26 to 124) Total (0 to 11) 19.7 (7 to 76) 10.0 (2 to 94) 34.0 (12 to 124) p values (B- vs C-) p < p < p = p < p values (B- vs B+) p = p = p = p = p values (C- vs C+) p = p = p = p = Table II. Rates of reduction, AVN and secondary surgery after FACT-R. Type Previous failed treatment No. hips Rate of reduction (%) (cases) Rate of AVN (%) (cases) Rate of secondary surgery (%) (cases) B (128) 1.6 (2) 9.4 (12) B (8) 0 (0) 33.3 (3) C (36) 0 (0) 27.8 (10) C (34) 0 (0) 42.9 (15) Total (206) 1.0 (2) 19.2 (40) p values (B- vs C-) p = 1 p = p = p values (B- vs B+) p < p = p = p values (C- vs C+) p = p = 1 p = AVN, avascular necrosis difference in the duration of step 1 (step 1, p = 0.354; step 2, p = 0.015; total duration, p = 0.033). The same pattern was observed in type C dislocations. The duration of step 2 in the previously treated group in type C dislocations was twice as long as in the group without previous treatment. Age- and severity-matched group analysis revealed that previous treatment specifically delayed step 2 but not step 1 in type C dislocations (step 1, p = 0.512; step 2, p = 0.006; total duration, p = 0.018). Outcomes. The rate of reduction was 99.0% (206/208 hips). In two children, FACT-R was abandoned at step 2, and they required closed reduction after adductor tenotomy under general anaesthesia. Both had failed previous treatment with a Pavlik harness. One was a six-month-old boy with a type B dislocation and the other was a tenmonth-old girl with a type C dislocation. All 164 hips with no previous treatment were successfully treated by FACT- R. There were no cases of redislocation, and no children required open reduction. Complications. There were some superficial skin problems such as redness or blisters, but they were adequately managed with wet dressings using plastic film. No pressure sores or compression neuropathies were recorded. There were no complications that could be attributed to prolonged bed rest, such as middle ear infections or pneumonia. Two cases of AVN (1.0%) were confirmed during follow-up. One was classified into group I and the other was group III according to Kalamchi and MacEwen classification. 20 At presentation, both were four-month-old girls with type B dislocations who were Ortolani positive. In one, acute spontaneous reduction occurred during the second step. In both children the period spent in traction was shorter than average: step1, seven and 12 days; step 2, two and six days, respectively and the total duration of traction was 12 and 20 days, respectively. Fortunately, the deformity of the femoral head remodelled satisfactorily in both children. The rate of secondary surgery in children without previous treatment was significantly higher in type C than type B DDH (p = 0.004, Table II). All those undergoing secondary surgery had a pelvic osteotomy, and four children with type C dislocations required simultaneous femoral varus derotation osteotomy. Acetabular dysplasia was considered to be severe in nine children and surgery was performed for these at the age of four years. In children who required secondary surgery, the mean age when FACT-R was commenced was significantly older (3.9 months vs 5.5 months, p < 0.001). Receiver operating characteristic curve analysis revealed, with moderate accuracy, that children presenting at > five months old needed secondary surgery significantly more often than younger children(area under the curve (AUC) = 0.70). Analysis of mean rates of secondary surgery between three different age brackets showed a significant difference (0 to 3 vs 4 to 6, p = 0.028; 0 to 3 vs 7 to 11, p < 0.001; 4 to 6 vs 7 to 11, p = 0.001, Table III). A history of previous failed treatment significantly increased the rate of secondary surgery (p < 0.001): 22 of 164 children (13.7%) without previous treatment needed secondary surgery, whereas 18 of 44 children (40.9%) with previous treatment needed secondary surgery. The parents or carers of six children with acetabular dysplasia declined secondary surgery at the age of five years. At their most recent follow-up, the dysplasia had improved in four. VOL. 97-B, No. 3, MARCH 2015

6 410 K. FUKIAGE, T. FUTAMI, Y. OGI, Y. HARADA, F. SHIMOZONO, N. KASHIWAGI, T. TAKASE, S. SUZUKI Table III. Results of FACT-R treatment by age group Age group (mths) Number of hips Type B Type C Previous failed treatment Mean hospital stay (days) (range) Number of AVN Rate of secondary surgery (%) (hips) 0 to (12 to 90) (8) 4 to (14 to 82) (21) 7 to (13 to 124) (11) Discussion The rate of reduction reported for children with DDH differs according to the method of treatment. The rate of failure after closed reduction under general anaesthesia is between 4% and 18%. 6,22 The use of a Pavlik harness, which is the most common form of treatment achieves spontaneous reduction in between 73.8% and 86% of cases. 1-3,11 However, Van de Sande and Melisie 23 reported that only 25% of Tonnis type 3 and 4 dislocations were reduced by the harness and Suzuki et al 11 reported that his type C severe dislocations were never reduced. In our experience there are three major reasons why severe dislocations have a lower rate of reduction with a Pavlik harness. The first is that the harness cannot bring the dislocated femoral head directly into the acetabulum; the second is that the residual muscle imbalance prevents complete reduction and/or causes recurrent dislocation; and the third is that soft tissue interposition may render the hip joint unstable. We believe that FACT-R addresses these three major problems. Preliminary traction counteracts the muscle imbalance and delivers the femoral head into the acetabulum. Monitoring the reduction with ultrasound and maintaining the position with padding while gradually reducing traction allows the femoral head to enter the acetabulum as the interposition decreases. By the time the spica is applied the hip has achieved its final position, thus ensuring stability. This may also explain why there were no recurrent dislocations. Salter et al 24 considered that a major cause of AVN during closed reduction is acute pressure on the femoral head, thought to be exacerbated by muscle contracture. This is supported by the finding that the incidence of AVN following acute closed reduction was reduced by preliminary adductor tenotomy. The role of preliminary traction may also reduce acute pressure by improving muscle balance. 5 The acute slip reduction described after use of a Pavlik harness 12 may cause an undue increase in intra-articular pressure. We suggest that FACT-R facilitates a more gradual reduction and addresses the muscle imbalance, thereby explaining our observed reduction in the rate of AVN, of which we observed two cases. In one, this may have been triggered by acute spontaneous reduction. In both children the duration of traction was shorter than average and may have been insufficient. We now recommend a minimum duration for step 1 of 14 days, and, for step 2, of seven days. Secondary surgery for residual dysplasia is also a concern in the management of DDH. The rate of secondary surgery reported in one long-term follow-up study of Pavlik harness treatment was 16.9% (22 of 130 cases). 25 In our group the rate of secondary surgery was comparable, at 19.2%. Luhmann et al 26 previously reported that delaying reduction until the appearance of the ossific nucleus more than doubled the need for secondary surgery. Children in our study who did not receive FACT-R treatment until the age of > five months had an increased rate of secondary surgery, thus emphasising the importance of early diagnosis and treatment. Both children who failed FACT-R treatment and required adductor tenotomy and closed reduction had failed previous treatment. The fact that these hips did not require open reduction may be due, in part, to the time they had spent in the FACT-R protocol. Previous treatment also increased the duration of FACT-R, especially step 2. We speculate that this may be due to increased contracture, exacerbated by the previous harness or cast maintaining the dislocated position. Unsuccessful treatment with a Pavlik harness should be discontinued as soon as possible. FACT-R necessitates a long period of hospitalisation, which is both costly and inconvenient. We appreciate that FACT-R may not be applicable or acceptable in all healthcare systems or socioeconomic circumstances. However, we suggest that it should be considered, especially in severe dislocations and when other methods have failed. In conclusion, FACT-R shows a high rate of reduction with a low risk of AVN. Sufficient release of muscle contracture by traction and gradual reduction under ultrasound control usually leads to a stable hip. Our protocol is a reliable option for the treatment of DDH. We anticipate that further research will show that this method is both consistent and reproducible. Supplementary material Photographs showing the procedures are available with the online version of this article at Author contributions K Fukiage: Data collection, Data analysis, Writing the paper. T. Futami: Data analysis, Performed the treatment. Y Ogi: Data collection, Data analysis, Y. Harada: Data collection, Data analysis, F. Shimozono: Data collection, Data analysis, N. Kashiwagi: Performed the treatment, Data analysis, Edit the paper. T. Takase: Performed the treatment. S. Suzuki: Performed the treatment, Data analysis, Edit the paper. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. This article was primary edited by E. Moulder and first proof edited by J. Scott THE BONE & JOINT JOURNAL

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