Journal of Pediatric Orthopaedics 21:80–88 © 2001 Lippincott Williams & Wilkins, Inc., Philadelphia

Transphyseal Osteotomy of the Distal Tibia for Correction of Valgus/Varus Deformities of the Ankle *John P. Lubicky, M.D., and †Haluk Altiok, M.D. Study conducted at Shriners Hospitals for Children, Chicago, Illinois, U.S.A.

Summary: This study is a retrospective review of the results of consecutive cases of a transphyseal osteotomy of the distal tibia. Indications for the procedure are significant valgus or varus deformities of the ankle needing acute correction because of problems with the skin and brace fit as well as progressive deformity. Twenty-one patients with a variety of underlying diagnoses, five with bilateral deformities, underwent this procedure. The technique involved making either a medially based closing or opening wedge with the distal limb of the osteotomy through the physis or the physeal scar so that it was very close

to the ankle joint. A fibular osteotomy was not necessary except in three ankles. All osteotomies healed. All patients were able to ambulate and use their braces as soon as their osteotomies healed, and none had any further pressure sores or brace-related problems, although some had mild residual valgus or varus deformities. There were no significant leg-length discrepancy problems as a result of the surgery. This osteotomy is a treatment alternative for significant angular deformities of the ankle that require acute correction. Key Words: Myelomeningocele—Valgus/varus ankle deformities—Tibial osteotomy.

Angular deformities of the ankle joint can cause significant problems with gait, shoe wear, brace fit, and/or the skin over bony prominences. These deformities have been observed in many different patient populations and have been studied extensively with regard to their cause and treatment. A traumatic or infectious insult to the distal tibial growth plate can result in significant varus angular change in the ankle alignment (6,7). Valgus angular deformities of the ankle joint are common acquired (6,10,11,18,19,22,24) or congenital (6,11,13,20,22,24) abnormalities of the fibula and tibia. A valgus angular deformity of the ankle joint is also a common clinical entity in the limbs of patients with neuromuscular conditions such as myelomeningocele, poliomyelitis, and cerebral palsy (4, 5,9,14,16). Many different surgical techniques have been tried over the years. All share common goals: to prevent further deformity, to achieve correction, and to allow resumption of normal activities as soon as possible. These surgical techniques include stapling of the medial distal tibial physis, fibular Achilles tenodesis, a tibial supramalleolar osteotomy, and a distal tibial wave osteotomy (1,3, 12,15,17,21,24). Many of these techniques have shortcomings with regard to the above-mentioned goals.

Stapling of the distal medial tibial physis requires enough growth-remaining potential to achieve correction and does so slowly. It is not ideal for a patient having significant skin problems requiring acute correction. The traditional supramalleolar tibial/fibular osteotomy is frequently complicated by delayed or nonunion of the tibia, requires concomitant fibular osteotomy, and often creates a secondary deformity. Fibular Achilles tenodesis cannot be done if the patient has a functional gastrocsoleus muscle (15). The distal tibial wave osteotomy, as described by Kumar et al. (12), addresses and solves some of the shortcomings of the supramalleolar-type osteotomy, yet saves the physis of the distal tibia. We report the technique, a transphyseal distal tibial osteotomy, which is accomplished at the level of the distal tibial physis/physeal scar for angular deformities of the ankle joint. To our knowledge, this technique has not been previously described. This technique proves to be simple, reliable, and helpful in correcting these deformities associated with many different conditions and etiologies (Fig. 1). SURGICAL TECHNIQUE The surgical technique is done under tourniquet control and starts with a medial incision centered over the malleolus that extends from just distal to the tip of the medial malleolus to as far proximal as needed based on the size of the wedge to be removed for correction of the valgus deformities. The periosteum is divided sharply and the distal tibia, including the epiphysis, is subperi-

Address correspondence and reprint requests to Dr. J. P. Lubicky, Shriners Hospitals for Children, 2211 N. Oak Park Avenue, Chicago, IL 60707, U.S.A. E-mail: [email protected] From *Shriners Hospitals for Children, Chicago; Department of Orthopaedic Surgery, Rush Medical College, Chicago; †Shriners Hospitals for Children, Chicago, Illinois, U.S.A.

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Power staples can be used around the osteotomy if needed. Two malleolar screws may be used in large patients. For varus deformities, no wedge is made to correct varus deformities. Once the pilot hole and the transphyseal osteotomy are made, the osteotomy site is spread open to the amount needed to correct the deformity. It is then held open by wedge-shaped tricortical iliac crest grafts. The metaphysis is drilled and a malleolar screw is passed, and, with tightening, compresses the grafts in the osteotomy site (Fig. 4A–D). After wound closure, a short-leg cast is applied. Non–weight-bearing status lasts about 4 weeks. If radiographs at that time show signs of healing, full weight bearing in the cast is allowed. Once bony healing has occurred, the patient resumes normal activities as well as the use of any preoperative orthotics. MATERIALS AND METHOD

FIG. 1. Illustrations of the steps of a transphyseal distal tibial osteotomy for valgus and varus ankle deformity correction.

osteally dissected anteriorly and posteriorly. Next, a pilot hole is drilled up through the medial malleolus to a point just proximal to the physis (Fig. 2A). After this, an osteotomy is performed with a power saw through the physis leaving the lateral cortex intact (Fig. 2B). For valgus deformities, a second osteotomy is made at an angle to the first corresponding to the amount of correction needed. This is also done with a power saw ending at the lateral extent of the first osteotomy and the wedge is removed (Fig. 2C, D). Any residual physeal cartilage is removed from the osteotomy site and any remaining intact lateral cortex is divided with an osteotome. The foot and ankle are then rotated into varus and the correction is assessed. If insufficient, additional bone can be removed from the proximal fragment. Once the osteotomy closes properly with enough correction, the drill is passed through the previously made pilot hole. With the ankle held in the corrected position, the drill is advanced up through the metaphysis and out the lateral cortex of the tibia. The hole is measured and an appropriate size malleolar screw is passed after countersinking the malleolus (Fig. 2E, F). The screw should be centered in the sagittal plane (Fig. 2G). This affords excellent fixation. If the fibula is an impediment to correction—it usually is not—an oblique osteotomy is made and fixed with a plate and screws because this osteotomy is pulled apart in the process of correcting the valgus (Fig. 3A, B).

This study is a retrospective review of the results of consecutive cases of transphyseal osteotomies of the distal tibia that were done between 1991 and 1998. Indications for the procedure were significant valgus or varus deformities of the ankle needing acute correction because of problems with the skin or with the brace/shoe fit over the prominent medial or lateral side of the ankle in children over 8 years of age. Twenty-one patients who had this procedure were identified, and their charts and radiographs were reviewed. Five had bilateral deformities. The 21 patients had a variety of underlying diagnoses including myelomeningocele, Ollier’s disease, hereditary multiple osteochondromata, cerebral palsy, fibrous dysplasia, pseudarthrosis of the fibula, overcorrected clubfeet, fibular hemimelia complex, proximal femoral focal deficiency, translocation of chromosomes 3 and 20, infection, and trauma (Table 1). There were 14 male and 7 female patients with a mean age of 13.4 years (minimum, 9; maximum, 21) at the time of the index surgery. There were 23 valgus and three varus ankle deformities. The average valgus ankle deformity was 15.8° (minimum, 8°; maximum, 26°), and the average varus ankle deformity was 24.3° (minimum, 18°; maximum, 30°) (Table 2). Radiographic measurements were made on standing radiographs. At the time of surgery, 21 of the distal tibial physes were open, four were closed, and one was partially closed. In six ankles, the level of the distal fibular physis was above the level of the distal tibial physis, whereas in 11 it was at the same level and in nine it was below (15). The shape of the distal tibial epiphysis was classified according to Shapiro et al. (19): (a) two were normal, (b) four were type 1, (c) 10 were type 2, (d) six were type 3, and (e) four could not be classified because of closure of the physis (Table 3). RESULTS The mean follow-up for the patients was 1.8 years (minimum, 0.2; maximum, 8). All patients were evaluated with regard to complications, correction achieved, recurrence, necessity for a fibular osteotomy, healing of the osteotomy, and the effect of the osteotomy on the J Pediatr Orthop, Vol. 21, No. 1, 2001

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FIG. 2. The steps for the transphyseal osteotomy to correct a valgus ankle deformity. A: A drill is passed through the medial malleolus to a point just proximal to the physis (dashed line). B: The first cut is made through the physis using a power saw or an osteotome leaving the lateral cortex intact. C: For valgus deformities, a medially based wedge osteotomy is created by making a second cut at an angle to the first cut using a power saw or an osteotome. D: The wedge is removed. E: With the ankle held in corrected position, the drill(s) is(are) advanced through and beyond the previously made pilot hole and out the lateral cortex of the tibia. F: An appropriate size malleolar screw(s) and, if needed, staples are used for internal fixation. G: The screw(s) should be centered in the sagittal plane.

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FIG. 3. Radiographs of a patient with hereditary multiple osteochondroma and a valgus ankle deformity who required a simultaneous fibular osteotomy. A: Preoperative anteroposterior ankle radiograph. B: Anteroposterior and lateral ankle radiographs after osteotomies had healed.

limb growth. Because the tibial growth plate was completely destroyed in the proposed technique and the plafond was completely leveled even with a triangleshaped epiphysis, we expected no further deformity even in growing children. Therefore, some patients were not followed up beyond the point at which their osteotomies had healed if the ankle deformity was their only complaint. The only major complication was a deep wound infection in a myelomeningocele patient that required irrigation and debridement. In one patient with a proximal femoral focal deficiency, the tibial osteotomy had a delayed union. This eventually healed without any further intervention with a residual clinical valgus deformity of only 4°. One patient with a translocation of chromosomes 3 and 20 had a delayed union of the fibular osteotomy. One patient required a second surgery for removal of a prominent, tender medial malleolar screw. None of the patients had major neurovascular complications. The mean postoperative valgus deformity was 3.7° (range, 0–14°). The mean postoperative varus deformity was 5.7° (range, 0–19°). Eleven ankles that had a preoperative valgus deformity ended up having some varus. The 19° residual varus angulation was in a patient who had varus ankle deformities owing to infection. These varus ankle deformities were not corrected fully because of compensatory shape changes in the talus, but clinically the foot and ankle appeared to be in neutral alignment. In one myelomeningocele patient, a derotational distal tibial osteotomy on the same side as the index surgery was done 6 years later. Despite some residual radiographic valgus or

varus ankle deformities, all patients resumed their daily activities soon after their osteotomies healed. None of the patients had difficulty with brace fit or skin pressure sores after their surgeries. None of the patients developed a recurrent deformity during the follow-up period. Only three patients needed concomitant fibular osteotomies. These patients had valgus ankle deformities that measured 13°, 15°, and 26°. In five cases, we performed a distal fibular epiphysiodesis on the same side to prevent further deforming forces. One patient had a simultaneous distal tibial rotational osteotomy on the same side. Another patient had a simultaneous epiphysiodesis of the proximal tibia, and of the proximal and distal fibula on the side of the index surgery, which was longer than the other side. Four patients had leg-length discrepancies. The patient with congenital pseudarthrosis of the fibula required a pan genu epiphysiodesis of the opposite longer lower extremity during the follow-up period. The patient with a translocation of chromosomes 3 and 20 had a leglength discrepancy, with the side of the index surgery being long. This patient also had a simultaneous distal fibular, and proximal tibial and fibular epiphysiodesis on the same side. During his follow-up, he required a proximal tibia and fibula epiphysiodesis on the opposite side at bone age 13 years to prevent probable predicted overcorrection. The patient with hereditary multiple osteochondromata ended up with a leg-length discrepancy of 0.4 cm, the index surgery side being shorter. The patient with Ollier’s disease had a shorter lower extremity on the side of the index surgery. He has had two lengthenings on the same-side lower extremity and J Pediatr Orthop, Vol. 21, No. 1, 2001

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FIG. 4. Radiographs of a patient with a posttraumatic ankle varus deformity. A: Preoperative anteroposterior radiographs of the ankle. B: Intraoperative anteroposterior radiographs after osteotomy, insertion of a triangular tricortical iliac crest bone graft, and internal fixation. C: Postoperative standing anteroposterior radiographs of both ankles show complete correction of the varus deformity and healed osteotomy. D: Postoperative lateral standing radiographs of the ankle of the same patient.

will need further lengthenings in the future. Overall, leglength discrepancy problems were usually caused by the underlying condition rather than the index surgery. DISCUSSION Ankle varus or valgus deformities can cause significant functional problems for patients. Disturbance of normal gait, difficulties with shoe or brace fit, and skin problems are the usual consequences. Several different surgical techniques have been described in the literature (1,3,12,15,17,21,24). Both acute or gradual corrections using different methods share the same goals: to correct the deformity and, it is hoped, prevent recurrence thereby J Pediatr Orthop, Vol. 21, No. 1, 2001

resolving the problems that were caused by the initial malalignment of the ankle. Burkus et al. (3) used the technique of stapling the medial distal tibial physis to correct the valgus ankle deformities. In his study, 13 myelomeningocele patients with 25 ankle deformities were followed. According to Burkus et al., for the patient to benefit from this surgery, the patients had to have at least 24 months of skeletal growth remaining at the time of surgery. Although patients were encouraged to walk after surgery, there were no specific data provided in regard to time period when the patients with skin breakdown and painful ankles returned to normal activity levels. Four patients in this group required a second surgery owing to staple migra-

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TABLE 1. Characteristics of patients who had transphyseal osteotomy of the distal tibia Case

Diagnosis

Gender

Side

Previous treatment (related)

1 2 3 4 5 6 7 8 9 10 11 12 13

Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Olliers PFFD PFFD CP

M F F M F M F F F M M M M

B B B R R R L L L L L R L

14 15

Trauma Infection

M F

R B

16 17 18 19

Fibrous Dysplasia Pseudarthrosis of fibula S/p clubfoot Translocation of chromosomes 3 and 20 H multiple osteochondromata H multiple osteochondromata

M M M M

L L B L

B supramalleolar tibial osteotomies + Peabody transfers None None Subtalar fusion + split posterior tibialis tendon transfer Derotational supramalleolar tibial osteotomy B clubfoot releases Derotational supramalleolar tibial osteotomy Supramalleolar tibial osteotomy Clubfoot releases × 2 Tibial Ilizarov external fixator lengthening Van Ness rotational osteotomy + knee fusion Van Ness rotational osteotomy Tibial Ilizarov external fixator lengthening + proximal tibial physeal bar excision Tibial Ilizarov external fixator lengthening + skin flap coverage L tibial Ilizarov external fixator lengthening + tal + distal fibular epiphysiodesis and R. distal tibial opening wedge osteotomy + distal fibular epiphysiodesis Distal tibial varus producing osteotomy × 2 Distal tibial varus producing osteotomy B clubfoot releases × 2 None

M M

L L

None None

20 21

PFFD, proximal femoral focal deficiency; CP, cerebral palsy; S/p, status post; H, hereditary; M, male; F, female; B, bilateral; R, right; L, left; tal, tendo Achilles lengthening.

tion, and five ankles required a second surgery for staple removal to prevent excessive varus ankle angulation (>10°). Stevens and Toomey (23) described another technique called fibular Achilles tenodesis for correction of the valgus ankle deformity. Eighteen patients with 32 neurogenic ankle deformities were studied. Their mean follow-up was 2 years 10 months (range, 2 years to 4 years 9 months). Six ankles failed to improve after tenodesis. One of the shortcomings of this surgery was that it did not address concomitant tibial torsion. The authors stated that for the patients to benefit from this surgery, they should be between 4 and 10 years of age. This technique not only fails to provide acute correction of the deformity but also cannot be used in patients with a functional gastrocsoleus muscle. Supramalleolar osteotomy is another method for correction of varus or valgus ankle deformities. Sharrard and Webb (21) reported their study, which consisted of 14 valgus and two varus ankle deformities in myelomeningocele patients. Using their method, although immediate correction was obtained, a second surgery was needed for two relapses, all varus ankle deformities that required an open wedge osteotomy and one overcorrected case. For varus ankle deformity correction, the authors suggested a fibular osteotomy, but this was not found to be necessary except with some older patients. None of their patients younger than 10 years of age relapsed. Their mean follow-up period was 2 years (range, 18 months to 5 years). Abraham et al. (1) did another study on a supramalleolar corrective osteot-

omy for ankle deformities. In this study, 35 myelomeningocele patients with valgus ankle deformities were studied with a mean follow-up of 7 years 6 months (range, 2–19 years). The authors performed fibular osteotomies in each case to achieve better compression and centralization at the tibial cut surfaces. Ninetyone percent of the results were rated as excellent and good. Complications were classified as (a) recurrence of ankle valgus (five cases), (b) tibial fractures (five cases), (c) fibulotibia synostosis (four cases), (d) deep wound infection (one case), (e) premature closure of the distal tibial growth plate (two cases), (f) delayed union (two cases), (g) nonunion (one case), and (h) excessive tibial anterior bowing (one case). The authors recommended correction to at least 5° of varus at the time of surgery and stated that additional rotational deformities could also be corrected with this type of surgery. Kumar et al. (12) reported on two patients with valgus ankle deformities owing to hereditary multiple exostosis. They performed a new supramalleolar osteotomy technique (i.e., wave osteotomy) to prevent an unappealing step-off of the medial cortex of the distal tibia and shortening of the extremity secondary to a closed wedge supramalleolar osteotomy. In their study, the fibula was also osteotomized and no complications were reported. When we started to perform our distal tibial transphyseal osteotomy, we aimed to achieve several goals. The first was to be as close to the site of deformity as possible so that maximum correction could be obtained without creating a secondary deformity above. The secJ Pediatr Orthop, Vol. 21, No. 1, 2001

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J. P. LUBICKY AND H. ALTIOK TABLE 2. Results of transphyseal osteotomy of the distal tibia for ankles studied Preop deformity

Case

Diagnosis

Postop deformity

Age (yr)

Valgus (deg)

Varus (deg)

Valgus (deg)

Varus (deg)

1 2 3 4 5 6 7 8 9

Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele

11.0 11.0 11.0 11.0 10.0 10.0 16.7 12.6 11.0

23 15 13 13 11 12 26 15 20

— — — — — — — — —

— — — — — — 14 4 1

4 5 1 1 6 6 — — —

10 11 12 13 14

Myelomeningocele Myelomeningocele Myelomeningocele Ollier’s PFFD

15.0 12.6 12.6 11.0 9.0

13 22 10 24 13

— — — — —

5 — — 6 4

— 4 2 — —

15 16 17 18 19 20 21

PFFD CP Trauma Infection Infection Fibrous dysplasia Pseudarthrosis of fibula

11.0 21.0 13.7 10.4 10.4 16.6 10.0

10 13 — — — 23 15

— — 18 25 30 — —

4 2 — — — 0 —

— — 0 19 10 — 10

22 23 24

S/p clubfoot S/p clubfoot Translocation of chromosomes 3 and 20 H multiple osteochondromata H multiple osteochontromata

13.7 13.7 11.3

13 10 8

— — —

— — 0

6 7 —

14.5 15.3

16 26

— —

4 1

— —

25 26

Complication

Infection; irrigation and drainage

Delayed union of tibial osteotomy

Tender screw head + removal Delayed union of fibular osteotomy

F/U (y) 1.7 1.7 0.9 0.9 1.1 1.1 0.2 3.1 0.2 5.2 8.0 0.3 2.0 0.5 0.2 0.3 5.3 0.3 0.3 0.7 7.7 0.2 0.2 2.6 3.0 0.7

PFFD, proximal femoral focal deficiency; CP, cerebral palsy; S/p, status post; H, hereditary; F/U, follow-up.

ond was to avoid the frequent problem of non- or delayed union seen in neuromuscular patients by doing the osteotomy entirely in metaphyseal bone. Along with that, early healing would allow resumption of normal activities as soon as possible. The third was to prevent recurrence by eliminating the physis of the tibia because the physis of the tibia—and probably the physis of the epiphysis—is “sick” in these patients. A major concern in this regard was the potential effect of the osteotomy on the limb growth with the subsequent development of a limb-length discrepancy. There are several reports on studies of the growth of the fibula and tibia. Ogden and McCarthy (17) in their study found that physiologic epiphysiodesis to the metaphysis occurs from 12 to 14 years in girls and from 15 to 18 years in boys. Closure of the distal tibial physis has a fairly characteristic pattern initially involving the medial portion and extending to the lateral portion later. This medialto-lateral pattern may occur over a 1.5-year period. As noted by Beals and Skyhar (2) in Blount’s text, Digby found that in the tibia the proximal growth plate contributes approximately 60% and the distal growth plate contributes approximately 40% of the total growth. However, the rate of growth of these growth plates is not constant, and the relationship of the proximal and distal growth rates can be expected to change with age. Hert (8) J Pediatr Orthop, Vol. 21, No. 1, 2001

measured the variation in growth rate based on the point of entry of nutrient vessels. Hert, as noted by Makin (14), found that at birth the tibia is 20% of its total length. Until 50% of its length has been reached, the lower tibial physis is the dominant one. The upper tibial physis then resumes the major role. The fibula at birth is 20% of its total length, but its lower physis is dominant only for 30% of its growth, after which the proximal physis predominates. This physeal role reversal is peculiar to the tibia and fibula. In light of these studies, we believe that after a certain age, usually after age 9 years, an osteotomy through the distal tibial physis will not cause any significant leg-length discrepancy in and of itself. This was borne out in our series. All patients were evaluated with regard to the safety of the procedure, healing potential of the osteotomy, correction achieved, recurrence, and the potential effect of the osteotomy on the limb growth. All osteotomies healed without nonunion or pseudarthrosis. Clinically, all patients were able to ambulate and use their braces as soon as their osteotomies had healed. None of the patients had any further clinical skin- or brace-related problems, although some had mild residual valgus/ varus deformities. None of the patients had any significant leg-length discrepancy problems as a result of the surgery.

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TABLE 3. Distribution of characteristics of distal tibial epiphysis and level of distal fibular physis for ankles studied Case

Diagnosis

Physis

Shape of epiphysis (Shapiro classification)

Level of distal fibula physis (Malhortha classification)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Myelomeningocele Ollier’s PFFD PFFD CP Trauma Infection Infection Fibrous dysplasia Pseudarthrosis of fibula S/p clubfoot S/p clubfoot Translocation of chromosomes 3 and 20 H multiple osteochondromata H multiple osteochondromata

Open Open Open Open Open Open Closed Open Open Open Open Open Open Open Open Closed Open Closed Closed Partially closed Open Open Open Open Open Open

Type 3 Type 3 Type 2 Type 2 Type 2 Type 2 Unclassified Type 2 Type 2 Type 3 Type 2 Type 1 Type 3 Normal Type 1 Unclassified Normal Unclassified Unclassified Type 3 Type 3 Type 1 Type 2 Type 1 Type 2 Type 2

Level Level Level Level Above Level Level Above Level Above Below Level Above Below Below Below Below Below Below Level Above Below Level Below Level Above

PFFD, proximal femoral focal deficiency; CP, cerebral palsy; S/p, status post; H, hereditary.

SUMMARY 8.

The transphyseal distal tibial osteotomy has been found to be effective because it provides correction very close to the joint and eliminates further progression of the deformity owing to growth abnormalities of the affected physis(es). It requires simple internal fixation, heals readily, and usually does not require a concomitant fibular osteotomy. Because the level of the osteotomy is close to the joint, it does not create a secondary deformity to achieve correction. This osteotomy is a treatment alternative for significant angular deformities of the ankle that require acute correction in children older than 9 years of age.

10.

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