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Recurrent Dislocations and Complete Necrosis:The Role of Pelvic Support Osteotomy

In Ho Choi, MD, Tae-Joon Cho, MD, Won Joon Yoo, MD, and Chang Ho Shin, MD

Abstract: The basic concepts and goals of pelvic support os-teotomy (PSO) are to enhance femoro-pelvic stability by prox-imal femoral valgus osteotomy and to improve hipbiomechanics by displacing the center of gravity medially, whichresults in an improvement in the mechanical efficiencies of ab-ductor muscles. However, the clinical application of traditionalPSO is limited due to its intrinsic shortcomings. Ilizarov de-signed a modied PSO, so called Ilizarov hip reconstruction(IHR), which incorporated a second distal femoral osteotomy,to realign the knee joint and to correct limb-length discrepancyand proximal femoral valgus osteotomy for pelvic support. IHRremains as a viable option for the salvage of severely damagedhips in the adolescents and young adults in whom arthrodesis orhip arthroplasty is not suitable. The purpose of this article is tobriey review the evolution of PSO and to concentrate on thetechnical considerations and outcomes of IHR.

Key Words: pelvic support osteotomy, Ilizarov hip re-construction, hip instability

(J Pediatr Orthop 2013;33:S45S55)

The treatment of hip instability in adolescents andyoung adults is often related to severe dysplasticacetabulum, proximal migration of the femur, and/or theabsence of part or all of the femoral head and neck, andpresents a surgical challenge. Furthermore, reconstructiveprocedures for this difficult problem, such as, greatertrochanteric arthroplasty, hip arthrodesis, pelvic osteot-omy, femoral osteotomy, and Girdlestone operation, areless than satisfactory. 1 Different methods of proximalfemoral (PF) subtrochanteric valgus angulation osteot-omy, known as pelvic support osteotomy (PSO), 211 havebeen described to salvage the damaged hips in whom

arthrodesis or hip arthroplasty are not appropriate.Support of the pelvis is achieved by means of a valgusosteotomy that places the superior end of the femuragainst the lateral aspect of the pelvis. 12 PSO is a usefulsurgical procedure that offers a signicant improvement

in posture, gait, and walking tolerance to those adoles-cents and young adults 13 who have unstable hips showingsevere dysplastic acetabulum and partial or total absenceof the femoral head and neck ( Table 1 ).

The purpose of this section of the symposium is toaddress the roles of PSO and Ilizarov hip reconstruction(IHR), a modied form of PSO, which combines distalfemoral (DF) osteotomy for concomitant lengthening and

varus angulation, for the management of recurrent dis-locations and complete necrosis of the femoral head. 1419We will briey review the histories of PSO and IHR andelaborate on the technical considerations and outcomes of IHR, based upon an extensive review of the literature andpersonal experience.

BRIEF HISTORY AND RATIONALE OF PSOAND IHR

PSO has long history in orthopaedic surgery. Thetechnique was developed and popularized by Lorenz, 2Von Bayer, 3 Schanz, 4 Milch, 58 and Henderson 10 but wasrapidly replaced by total hip replacement arthroplasty(THRA). Henry Milch 58 expanded the concept andpopularized the PSO in the United States during the mid-20th century. The basic concepts and goals of PSO are toenhance femoro-pelvic stability by PF valgus osteotomyand to improve hip biomechanics by displacing the centerof gravity medially, which results in an improvement inthe mechanical efficiencies of abductor muscles. 57,20 Thechange of joint biomechanics seems to be more importantthat the anatomic support to reduce painful instabilityand to improve hip function. 21 Overcorrection of PFvalgus osteotomy places the extremity in a xed abduc-tion position relative to the pelvis to eliminate hip ad-duction and reduces or prevents the Trendelenburg sign

because the contralateral pelvis cannot drop. 12,20 How-ever, the clinical application of traditional PSO is limiteddue to its intrinsic shortcomings. In particular, the opti-mal extent of angulation is difficult to achieve. If the angleis too large, excessive genu valgum, xed pelvic obliquity,and impingement pain on adduction of the lower ex-tremity to the neutral position may ensue. Alternatively, if the angle is too small, the result would be an insufficientimprovement in hip biomechanics, 6,9,20,22,23 and mostimportantly, the issue of remaining limb-length discrep-ancy (LLD) cannot be addressed. 19

To overcome the shortcomings of traditional PSO,Ilizarov designed a modied PSO, which incorporated a

From the Division of Pediatric Orthopedics, Seoul National UniversityChildrens Hospital, Seoul, Korea.

None of the authors received nancial support for this study.The authors declare no conict of interest.Reprints: In Ho Choi, MD, Division of Pediatric Orthopedics, Seoul

National University Childrens Hospital, Seoul 110-744, Korea.E-mail: [email protected] .

Copyright r 2013 by Lippincott Williams & Wilkins

H IP D ISORDERS SUPPLEMENT

J Pediatr Orthop Volume 33, Number 1 Supplement, July/August 2013 www.pedorthopaedics.com | S45
mailto:[email protected]:[email protected]


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second DF osteotomy, to realign the knee joint and tocorrect LLD, and PF valgus osteotomy for pelvic sup-port. Russian literature indicates that Ilizarov and hisassociates started to use a modied PSO technique in theearly or mid-1970s. 1517,22,23 Ilizarov emphasized the im-portance of PF extension to correct the xed exion de-

formity of the hip and to permit locking of the hip jointby stabilizing the hip in the sagittal plane during singlestance. 12,14,18,19

IHR is considered a breakthrough in terms of re-solving the inherent problems of PSO, as the treatmentgoals for normal gait are to obtain stability by re-constructing a stable fulcrum, to improve energy effi-ciency by restoring abductor mechanism, and to improvecosmetic appearance by eliminating shortening/jointcontracture-related problems.

INDICATIONS OF IHRIHR is most suitable for skeletally mature adoles-

cents or young adults that present with an unstable hipthat is mobile and associated with a Trendelenburg gait(T-gait) and a large LLD. IHR is highly effective ateliminating T-gait, particularly when there is good ab-ductor muscle function before surgery. The 2 most fre-quent indications are a neglected or an unsuccessfullytreated developmental dislocation of the hip 2426 and se-vere septic hip sequelae. 1,12,2628 IHR is also indicated forthe treatment of hip instability related to paralytic sub-luxation/dislocation, posttraumatic hip subluxation/dis-location, spondylo-epiphyseal dysplasia, 29 osteonecrosisof the femoral head, 30 and postexcision arthroplasty 31(Table 2 ).

It seems that IHR is not ideal for young children,because in accordance with Wolffs law, gradualstraightening of the PF tends to occur at the site of valgusangulation and this results in loss of pelvic support. Al-though IHR is not contraindicated in young children, forexample, when hip instability is associated with markedLLD due to multiple lower-limb growth disturbancessecondary to neonatal sepsis, one should expect repeatIHR at or near skeletal maturity. Another alternative is toundergo femoral lengthening without a PSO, insertinghalf pins into the pelvis to prevent proximal migration of the femur, in the younger age, and subsequently performIHR when the patients are near skeletal maturity. 12

TECHNICAL CONSIDERATIONS OF IHRCareful preoperative surgical planning, based on

data obtained from clinical and radiographic assessments,is essential to achieve a level pelvis and to restore themechanical axis of the lower limbs perpendicular to thehorizontal line of the pelvis in bipedal stance. 1,12,13 Im-

portant technical considerations of IHR are summarizedas follows. 1,1214,191. Although some authors have recommended proximal

osteotomy, in which the acetabulum rests on the lessertrochanter, 3,11 most prefer more distal osteotomy inthe anticipation of abductor mechanical benets dueto displacement of the center of gravity medially. Todetermine the optimal level of PF valgus osteotomy,the femoral shaft should be fully adducted against thelateral wall of the pelvis, which is usually situatedsomewhere between the infracotyloid recess and theischial tuberosity. This renders longer proximal seg-ment and provides better hip stabilization and an

optimal location for soft tissue interposition toproduce a weight-bearing surface without direct abut-ment between the PF osteotomy and the pelvis ( Fig. 1 ).

2. How much valgus angulation is desirable? This issue ishighly controversial. In the era of conventional PSO,Henry Milch 6,8 emphasized that the postosteotomyangle ( b-angle: the obtuse angle formed between aline drawn along the inner aspect of the cortex of thedistal fragment and an oblique line drawn from theupper end of the distal fragment tangent to the mostmedial projection of the proximal fragment, whichmay be considered as the neck angle of the osteotom-ized femur) must not be permitted to far exceed theangle of inclination of outer pelvic wall in the levelpelvis ( a angle: the obtuse angle formed between anoblique line connecting the 2 points of the outer edgeof the acetabular roof and the outer edge of the ischialtuberosity and the mechanical axis line, passingthrough the outer edge of the acetabular roof,perpendicular to the horizontal pelvic reference line).He reported that the mean a -angle was 206.4 4.7degrees in females and 211.4 5.8 degrees in males.He insisted that postosteotomy angle should bebetween 210 and 230 degrees, because excessive valgusat the osteotomy site leads to PF abutment against thepelvis, and even pelvic tilt, when the patient tries tobring the involved extremity into a neutral adduction/

abduction position. 6,8,13 However, with contemporaryIHR, irrespective of the size of the overcorrectionof PF valgus angulation, much of the abductiondeformity caused by PF valgus angulation can becompensated, if the second DF osteotomy restores theposition of knee joint inclination to parallel thehorizontal line of the pelvis. The mean PF valgusangulation reported in the literature varied widelybetween 35 and 60 degrees. 12,20,26,29,3237 Paley 12,19(Fig. 1A ) recommended overcorrection of 15 to 20degrees during PF valgus osteotomy to eliminate hipadduction in addition to pelvic drop angle (the anglebetween the line perpendicular to iliac crest pelvic line

TABLE 1. Indications of Pelvic Support OsteotomyHip instability: severe dysplastic acetabulum

DDH: neglected, unsuccessfully treatedTraumatic hip dislocation with instabilityParalytic or spastic dislocation (postpoliomyelitis, cerebral palsy,

muscular dystrophy)

Partial or total absence of femoral head and neckSevere sequelae of septic arthritis (Choi type IV)Skeletal dysplasia (SED, Morquio, etc.)Severe AVNPost-Girdlestone resection arthroplasty

AVN indicates avascular necrosis; SED, spondylo-epiphyseal dysplasia.

Choi et al J Pediatr Orthop Volume 33, Number 1 Supplement, July/August 2013

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TABLE 2. Summary of the English Literature on Ilizarov Hip ReconstructionHip Function *

ReferencesEtiology

(No. Patient)Age at Op.

(y)

Type of Support

(No.Patient) Preop. Postop.

PostopTrendelenburg

Sign (No.Patient) Follow-up

Complications andComments

Samchukovand Birch 20

DDH (1) 15 Subacetab. NA NA None 5 mo NA

Kocaogluet al 32

DDH (11);PFFD (1);MMC (1);paralyticdislocat. (1)

20 (12-33) Subacetab. 64 (42-72) 84 (68-92) None (17); P (3) 68mo (55-81) 3 PTI 3; 1hypocorrection

Manzottiet al 28

Septic hip (15) 21.1 (14-36) Acetabular(9);subace-tab. (5);pubicramus (1)

NA 1.94 (W) None (9); P (6) 108mo (38-178) 3 knee sublux.; 2 lossof support; 2 pinsubstitute; 1peroneal n. palsy;1 regenerate fx.;1 foot ER

Inan et al 25 DDH (17) 24.8 (17-39) Subacetab. NA NA None (12); P (5) 36.3 mo (21-65) Many PTI; 2 fx.Rozbruch

et al 12Septic hip (8) 11.2 (7.8-14.2) Subacetab. 51 (21-67) 73 (64-79) None (6); P (2) 5y (1.9-9.8) 3 PTI; 2 knee

stiffness; 1 kneesublux.; 1prematureconsolidation; 1prox. migration of femur

Inan andBowen 33

DDH (12);septic hip (3);traumaticlux. (1)

25.3 (17-39) Subacetab. 50 (32-73) 87.6 (67-98) None (12); P (4) 52.5mo (26-84) 2 PTI; 2 delayedconsolidation; 1fracture; 1 kneestiffness; 1obturator n.entrapment

Inan et al 34 DDH (11) 25.2 (13-39) Subacetab. 52 (32-73) 92 (77-98) None (6); P (5) 36mo (23-59) NA; many PTIEl-Mowa 24 DDH (12);

septic hip (5);AVN (5);RP (4)

22.4 (19-35) Subacetab. 55 (40-78) 81 (65-90) None (20); P (5) 4.5 y (2-7) 4 of 5 patients withpersistent T-signwas RP

Emara 31 Excision

arthroplastyafter infectedhiparthroplasty(11)

51.9 (45-61) Subacetab. 43.5 (31-50) 70.9 (65-80) None (11) Minimum 2y 7 PTI; 2 knee

stiffness; 2 residualknee valgus; 3delayedconsolidation

Shetty et al 29 Spondylo-epiphysealdysplasiacongenita (8bilat.)

16.4 (9-25) Subacetab. 67.9 (54-85) 79.1 (68-87) None (6 hips); P(10 hips)

25.9 mo 3 PTI; 3 kneestiffness; 1 delayedconsolidation

Gursu et al 35 DDH (12 unilat.,1 bilat.); septichip (8)

22.6 (12-34) Subacetab. 48.2 (28-79) 80.1 (60-93) None (13 hips); P(8 hips)

33.5 mo (16-45) 15 PTI; 2 prox. fx.; 2delayed union; 6knee stiffness; 1depression

Krieg et al 36 Spina bida (1) 14 Subacetab. NA NA Improved 12 mo None; prox.: lockingcompression plate,

distal: FitboneMarimuthuet al 26

DDH (1);nonunion(NOF) (2);septic hip (6);tuberculois (3)

23 (13-32) Subacetab. 44.3 (14-73) 70.8 (60-86) None (9); P (3) 59.4mo (38-86) PTI almost all

Mahranet al 27

DDH (9); septichip (9); RP (2)

21.5 (14-30) Subacetab. NA NA None (13); P (7) 6 mo PTI almost all; 2regenerate fx.; 2prematureconsolidation; 4delayedconsolidation; 3residualLLD>3cm

J Pediatr Orthop Volume 33, Number 1 Supplement, July/August 2013 The Role of Pelvic Support Osteotomy

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and the femoral shaft in single stance or duringmaximum attempted adduction when supine). Onthe basis of our experiences, we recommend at least25 degrees of overcorrection, 1 and >30 degrees inpreadolescents. Pafilas and Nayagam 13 (Fig. 1B ) pro-posed overcorrection of 30 to 40 degrees of extravalgusin addition to the sum of maximum adduction rangeplus adduction contracture plus another 9 degrees tobring the femur parallel to the vertical axis perpendic-ular to the pelvic line. The remaining 21 to 31 degreesof abduction will take the femur away from midline.Their 30 to 40 degrees corresponds to 21 to 31 degreesof extravalgus in addition to the pelvic drop angle.Overcorrection is entirely empirical in anticipation of remodeling at the valgus osteotomy and some atrophyof the soft tissue interposed between the femur andlateral pelvic wall.

3. The next important issue is how to determine the levelof DF osteotomy. Paley 12,19 used the CORA method,which utilizes an imaginary proximal mechanical axisline ( Fig. 2A ). He stated that proximal mechanical axisline corresponds to a line perpendicular to thehorizontal pelvic line, passing through the point of 1/3 to 1/2 the distance lateral to the medial edge of the proximal fragment. In contrast, Kadykalo andKuftyev 22 presented a formula that took into consid-eration the amount of PF valgus and DF varus

angulation ( Fig. 2B ; Table 3 ). The mean DF varusangulations reported in the literature varied in therange between 10 and 22 degrees. 20,29,30,32 Otherimportant point of consideration when determiningthe level of distal osteotomy concerns the equalizationof distances between the midline of the body axis andthe centers of the knee joints of affected and normalcontralateral limbs, which was emphasized by Palasand Nayagam 13 (Fig. 2C ). This suggests that the levelof DF osteotomy relies on the level of PF valgusosteotomy, that is, the higher the level of PF valgusangulation, the more proximally located DF osteot-omy should be to equalize the distances of knee joints

from the midline of the body axis in bipedal stance.Furthermore, if there is no compensatory DF varusangulation, unequal knee distances from midline maycause secondary pelvic obliquity despite well-per-formed pelvic support.

4. The amount of extension should be adjusted to correcthip exion contracture and pelvic tilt, and thesacrofemoral angle (the angle formed by the inter-section of a line drawn along the top of the sacrum tolocate the pelvic inclination and a second line drawnalong the shaft of the femur on the standing lateralradiograph). In normal children and adolescents, thesacrofemoral angle measures between 50 and 65degrees. 38

5. The amount of derotation should also be determined,based on foot progression angle and the amount anddirection of rotation during passive maximum adduc-tion. The amount of varization is also controversial.Although Palas and Nayagam 13 proposed bringingthe femoral shaft parallel to the vertical midline axis,this may cause 9 degree of valgus inclination at theknee. We believe that the knee joint should berealigned to its physiological position even after DFvarus angulation.

6. The amount of lengthening should be recalculatedafter IHR during lengthening using a woodblock orscanogram to obtain a level pelvis. Overlengthening is

poorly tolerated in hips that are already in fulladduction after IHR.

7. Resection of the femoral head and neck remnant may beindicated, if the hip is painful and stiff, regardless of pre-existing osteoarthritis. The concept of resection-angula-tion osteotomy was originally proposed by Milch 7 in1955 for restoring hip mobility and pain relief.

SUMMARY OF THE ENGLISH LITERATUREON IHR

At the time of writing, only 12 original articles and 3case reports have been published in the English literature

TABLE 2. (continued )Hip Function *

ReferencesEtiology

(No. Patient)Age at Op.

(y)

Type of Support

(No.Patient) Preop. Postop.

PostopTrendelenburg

Sign (No.Patient) Follow-up

Complications andComments

SabharwalandMacleod 30

Osteonecrosisafter leukemia(1)

13.5 Subacetab. 26 88 None 3 y Kneestiffness Z quadri-cepsplasty

Choi et al(unpublish-ed data)

Septic hip (11);DDH (2)

13.4 (6.4-16) Subacetab. 12 (W) 6 (W) None (8); P (5) 5 y (1-10.2) Repeat IHR in 3patients; 4 PTI; 4loss of support; 1prox. fx.

*Harris Hip Score or a modied Harris Hip Score. 12

AVN indicates avascular necrosis of the femoral head; bilat., bilateral; DDH, developmental dislocation of the hip; dislocat., dislocation; ER, external rotation; fx.,fracture; IHR, Ilizarov hip reconstruction; LLD, limb-length discrepancy; lux., luxation; MMC, meningomyelocele; n., nerve; NA, unknown; NOF, nonunion of femurneck fracture; op., operation; P, reduced but persistent T-sign; PFFD, proximal femoral focal deciency; postop., postoperative; preop.; preoperative; prox., proximal; PTI,pin-tract infection; RP, residual poliomyelitis; subacetab., subacetabular; T, Trendelenburg; unilat., unilateral; W, WOMAC score.




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on the merits of IHR ( Table 2 ). Samchukov and Birch 20reported the successful use of IHR to treat a xed, irre-ducible congenital dislocation of the hip associated withother multiple lower extremity growth disturbances sec-ondary to neonatal multifocal osteomyelitis. Kocaogluet al 32 used IHR for the treatment of hip dislocation in 14patients in adolescents and young adults (mean age, 20 y)

with a mean LLD of 4.4cm. The clinical outcome wassatisfactory: pain subsided in all patients, the Trendelen-burg sign became negative in all but 3 patients, no patienthad LLD, and lower limb alignment was reestablished.Manzotti et al 28 reviewed their experience with IHR totreat late sequelae of septic arthritis of the hip in 15 pa-tients (mean age, 21.1 y) with a mean LLD of 6.5 cm. At

FIGURE 1. Determination of valgus angulation of the proximal femur for Ilizarov hip reconstruction. A, Paley 12,19 recommendedovercorrection of 15 to 20 degrees during valgus osteotomy to eliminate hip adduction and pelvic drop angle, which is an anglebetween the line perpendicular to iliac crest pelvic line and the femoral shaft in single stance or during maximum attemptedadduction in the supine position. On the basis of our experiences, we recommend at least 25 degrees of overcorrection 1 and >30degrees in preadolescents. B, Pafilas and Nayagam 13 proposed overcorrection of 30 to 40 degrees of extravalgus in addition tothe sum of maximum adduction range plus adduction contracture plus another 9 degrees to bring the femur parallel to the

vertical axis perpendicular to the pelvic line. The remaining 21 to 31 degrees of abduction will take the femur away from midline.Their 30 to 40 degrees corresponds to 21 to 31 degrees (b a) of extravalgus in addition to the pelvic drop angle. Overcorrectionis entirely empirical in anticipation of remodeling at the valgus osteotomy and some atrophy of the soft tissue interposed betweenthe femur and lateral pelvic wall.




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an average follow-up of 108 months after removal of thexator, 10 patients had an excellent or good result,whereas 5 patients had a fair (LLD > 2.5 cm, de-formity > 10 degrees, decreased hip and/or knee rangeof motion between 10 and 20 degrees, a positiveTrendelenburg sign, or mild pain) or poor(LLD > 5 cm,deformity> 10 degrees, loss of hip and/or knee rangeof motion >20 degrees, or continuous pain) result.Rozbruch et al 12 similarly reported the results of IHR forthe treatment of the late sequelae of infantile hip infectionin 8 patients (mean age, 11.2y) with improvement in pain,gait, LLD, and lower-limb alignment. At a mean follow-up of 5 years (range, 1.9 to 9.8 y), LLD improved from a

FIGURE 2. Determination of varus angulation of the distal femur for Ilizarov hip reconstruction. A, The CORA method recom-mended by Paley, 12,19 which utilizes an imaginary proximal mechanical axis line. The proximal mechanical axis line correspondsto a line perpendicular to the horizontal pelvic line, passing through the point of 1/3 to 1/2 the distance lateral to the medial edgeof the proximal fragment. B, Preoperative simulation of the Ilizarov hip reconstruction, which utilizes a trigonometric equation,recommended by Kadykalo and Kuftyev, 22 taking into consideration of proximal femoral (PF) valgus angulation and distal femoralvarus angulation and the biomechanical limb axis after reconstruction ( Table 3 ). C, When determining the level of distalosteotomy, the equalization of distances between the midline of the body axis and the centers of the knee joints of affected andnormal contralateral limbs should be considered, which was emphasized by Pafilas and Nayagam. 13 The level of distal femoralosteotomy relies on the level of PF valgus osteotomy, that is, the higher the level of PF valgus angulation, the more proximallylocated distal femoral osteotomy should be to equalize the distances of knee joints from the midline of the body axis in bipedalstance.

TABLE 3. K-Value in the Design of the Biomechanical Axis 22(Refer to Fig. 2B, a = K L)

a (Deg.)

b (Deg.) 5 10 15 20 25 30 35 40

5 0.50 0.67 0.76 0.81 0.85 0.87 0.89 0.9110 0.34 0.51 0.61 0.68 0.74 0.78 0.81 0.8415 0.26 0.41 0.52 0.60 0.66 0.71 0.75 0.7820 0.21 0.35 0.45 0.53 0.60 0.65 0.71 0.7425 0.17 0.30 0.40 0.48 0.55 0.61 0.66 0.7130 0.15 0.27 0.37 0.45 0.51 0.58 0.63 0.6835 0.14 0.25 0.34 0.42 0.49 0.55 0.61 0.6740 0.12 0.23 0.31 0.40 0.47 0.53 0.59 0.65




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mean of 4.6 (range, 0.6 to 6.4cm) to 0.8 cm (range, 0 to1.2cm). Modied hip score improved from a mean of 51(range, 21 to 67) to 73 points (range, 64 to 79). Gaitanalysis data, which was performed in 5 patients, revealedthat the mean stance-time asymmetry improved from16% to 5.4%, and the mean ground-reaction force (sec-ond peak) improved from 102% of body weight to 122%of body weight. El-Mowa et al 24 reported on the use of IHR in a study of 25 patients (mean, 22.4 y) with unstablehips. At a mean follow-up of 4.5 months, all patients werereported to be pan free with improvement in gait and

LLD. Four of 5 patients with persistent Trendelenburgsign had residual poliomyelitis. Marimuthu et al 26 andMahran et al 27 also reported overall satisfactory results of IHR for chronically dislocated hips or destructed hips dueto various causes. Gursu et al 35 studied the inuence of etiology of hip instability on the results of IHR. Precedingpathology included neglected congenital dislocation of the hip in 13 hips (12 patients) and septic hip sequelae in 8hips. At a mean follow-up of 33.5 months, there was nosignicant difference between the nal Harris Hip Scoresof the 2 groups. They observed that complications were

FIGURE 3. A case of Ilizarov hip reconstruction complicated by refracture at the level of valgus angulation. A, Preoperativeradiograph of the pelvis taken in the standing position in a 12-year and 5-month-old boy with complete absence of the femoralhead and neck after infantile septic arthritis of the hip. B, A radiograph showing Ilizarov hip reconstruction and 6 cm length gainwith use of circular fixator. C, A radiograph showing refracture at the level of valgus angulation at age 15 years. D, A radiographshowing repeat Ilizarov hip reconstruction using a monolateral fixator. Three centimeter length gain was obtained. E, A tele-radiogram of the lower extremities taken at age 21 years showing a well-performed pelvic support, in which the acetabulum is

rested on the lesser trochanter.




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more frequent after congenital dislocation of the hip, andpatient satisfaction was higher in cases with sequelae of sepsis.

Emara 31 reported the results of IHR in 11 patientswho had undergone excision hip arthroplasty to treatresistant hip infection. Harris Hip Scores improved in allpatients: the average score preoperatively was 43.5 (range,31 to 50), whereas at nal follow-up, the average scorewas 70.9 (range, 65 to 80). Shetty et al 29 reported theefficacy of a modied PSO using hybrid external xator in8 patients (mean age, 16.4 y) with severe bilateral hip in-volvement in spondylo-epiphyseal dysplasia congenita.After a mean follow-up of 25.9 months, the mean modi-ed Harris Hip Score had improved from 67.9 to 79.1points. Waddling gait was absent in 3 patients, reduced in4 patients, and was the same in 1 at the last follow-up.Mean LLD was >0.5 cm, and the mechanical axis wasrealigned in all. Sabharwal and Macleod 30 reported a case

of successful IHR for the management of advanced os-teonecrosis of the proximal femur after chemotherapy foracute lymphoblastic leukemia in an adolescent. Theyperformed the 2-level femoral osteotomy with acute val-gus-extension angulation at the PF osteotomy site and theDF osteotomy for gradual lengthening and varus angu-lation using Taylor Spatial Frame (Smith and Nephew,Memphis, TN).

Monolateral external xation is usually more com-fortable than circular frames for the patient with de-formity around the hip and proximal femur, Inan andBowen 33 reported on the use of monolateral externalxator (Orthox S.R.L.; Bussolengo, Verona, Italy) for

IHR in 16 patients (mean age, 25.3 y). At a mean follow-up of 52.5 months, the mean Harris Hip Score increasedfrom 50 points (range, 32 to 73 points) preoperatively to87.6 points (range, 67 to 98 points). Four patients retaineda positive Trendelenburg sign. We have also experiencedthat monolateral xator that enables multiplanar angularcorrection and translation (Dyna-ATC; BK Meditech,Seoul, Korea) were suitable for IHR. Recently, Krieget al 36 proposed a new technique of IHR with internalsystems exclusively. A locking compression plate is ap-plied to x the PF valgus-extension osteotomy and amotorized retrograde intramedullary lengthening device(Fitbone; Wittenstein, Igersheim, Germany) for the distal,lengthening-varization osteotomy. Although the use of internal implants for IHR is a feasible and patient-friendlyalternative to traditional methods, their use, however, maybe restricted by geometric preconditions.

Reported complications of IHR in the literature

(Table 2 ) included knee stiffness, pin-tract infection, de-layed consolidation, refracture ( Fig. 3 ), obturator nerveentrapment, straightening of proximal valgus angulation,and persistent T-gait. We think that there is possibility of ischiofemoral impingement if the PF valgus angulationsite directly abuts the ischium.

DISCUSSION

How to Avoid or Reduce Remodeling of Proximal Valgus Angulation?

IHR is safe to perform at an older age, preferablyafter peak growth spurt. Rozbruch et al 12 observed that

FIGURE 4. The newly reconstructed weight-bearing area is not absolute, nor a true joint or false articulation. A, A radiograph of Ilizarov hip reconstruction in a 15-year and 1-month-old boy. B, When determining the center of rotation during adduction/abduction motion, the main fulcrum is seemingly located around the lesser trochanter and not around the apex of the valgusangulation adjacent to the ischial tuberosity during passive abduction and adduction. This suggests that the center of rotationseems to vary with the position/direction of motion of the lower limbs and depends on the soft-tissue interpositional weight-bearing surface between the PF osteotomy and the pelvis.




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when IHR was performed at a younger age before ado-lescence, the PF valgus osteotomy site completely re-modeled, demonstrating no evidence of the pelvic supportwithin 1 or 2 years after the operation. We also experi-enced the same phenomenon of remodeling (straighten-ing) of the proximal femur when IHR was performed in

the preadolescent age. One should consider adding ex-travalgus angulation at the PF osteotomy site, whenperforming IHR to address marked LLD in a youngerage. As mentioned previously, one should expect repeatIHR at or near skeletal maturity to obtain a level pelvisand to eliminate residual LLD. Another alternative is toperform simple femoral lengthening with extension of theexternal xation to the pelvis at a younger age and toreserve PSO for the second lengthening when the patientsare near skeletal maturity. 12

In our experience, translation of the proximalfragment medially relative to the distal fragment helpsfacilitate and maintain valgization. Prebent plate xation

may also be benecial. Most importantly, postoperativestrenuous abductor muscle exercise is essential.

Where Is the Weight-bearing Fulcrum?We agree with others

12,13that the weight-bearingarea is not absolute, nor a true joint or false articulation.

The center of rotation seems to vary with the position/direction of motion of the lower limbs and depends on thesoft-tissue interpositional weight-bearing surface betweenthe PF osteotomy and the pelvis. To identify the center of rotation during adduction/abduction motion, we usedcineradiography in a patient who underwent Shanz-typePSO and managed to gure out that the center of rotationwas located around the lesser trochanter and not aroundthe apex of the valgus angulation adjacent to the ischialtuberosity during passive abduction and adduction(Fig. 4 ).

FIGURE 5. Total hip replacement arthroplasty (THRA) performed in a Mongolian 34-year-old lady who underwent Ilizarov hipreconstruction for treatment of neglected developmental dislocation of the hip at 24 years of age in Russian Federation. Sheunderwent THRA because of diffuse pain around the buttock and hip that had lasted after Ilizarov hip reconstruction. A and B,Preoperative radiographs of the hip. The deformed femoral head is still in close contact with the secondary socket (false ace-tabulum) of the dislocated hip, which may explain the source of pain. The pelvic support osteotomy without resection of thefemoral head might have been contraindicated in this regard. C, Three-dimensional computed tomography of the hip. D and E,Postoperative radiograph of THRA with a straight stem inserted after 4.5 cm of segmental shortening at the subtrochanteric level.




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21. Schiltenwolf M, Carstens C, Bernd L, et al. Late results aftersubtrochanteric angulation osteotomy in young patients. J PediatrOrthop B . 1996;5:259267.

22. Kadykalo OA, Kuftyev LM. Some biomechanical principles of the hipreconstruction with defect on head and neck of the femur by Ilizarovmethod. The Value of General Biological Patterns in RegenerationTissue Opened by G.A. Ilizarov. Scientific Works Collection . 13th ed.

The Ministry of Health, The RSFSR (The Russian Soviet FederativeSocialist Republic) Kurgan All-Union Scientific Center: Rehabilita-tion Traumatology and Orthopaedics; 1988:124129.

23. Samchukov ML, Ivanova IV, Dolganov DV. Analysis of Pelvo-Trochanteric Muscles and Weight-Bearing After Ilizarov Femoral Reconstruction in Patients With Hip Osteoarthritis . USSR: TheCongress of Scientific and Technical Advances of the YoungScientists of the Urals; 1986:8687.

24. El-Mowafi H. Outcome of pelvic support osteotomy with theIlizarov method in the treatment of the unstable hip joint. ActaOrthop Belg. . 2005;71:686691.

25. Inan M, Bomar JD, Kucukkaya M, et al. A comparison between the useof a monolateral external fixator and the Ilizarov technique for pelvicsupport osteotomies. Acta Orthop Traumatol Turc . 2004;38:252260.

26. Marimuthu K, Joshi N, Sharma CS, et al. Ilizarov hip reconstruc-tion in skeletally mature young patients with chronic unstable hip joints. Arch Orthop Trauma Surg . 2011;131:16311637.

27. Mahran MA, Elgebeily MA, Ghaly NA, et al. Pelvic supportosteotomy by Ilizarovs concept: is it a valuable option in managingneglected hip problems in adolescents and young adults? StrategiesTrauma Limb Reconstr . 2011;6:1320.

28. Manzotti A, Rovetta L, Pullen C, et al. Treatment of the latesequelae of septic arthritis of the hip. Clin Orthop Relat Res .2003;410:203212.

29. Shetty GM, Song HR, Lee SH, et al. Bilateral valgus-extensionosteotomy of hip using hybrid external fixator in spondyloepiphy-seal dysplasia: early results of a salvage procedure. J Pediatr OrthopB. 2008;17:2125.

30. Sabharwal S, Macleod R. Ilizarov hip reconstruction for themanagement of advanced osteonecrosis in an adolescent withleukemia. J Pediatr Orthop B . 2012;21:252259.

31. Emara KM. Pelvic support osteotomy in the treatment of patientswith excision arthroplasty. Clin Orthop Relat Res . 2008;466:708713.

32. Kocaoglu M, Eralp L, Sen C, et al. The Ilizarov hip reconstructionosteotomy for hip dislocation: outcome after 4-7 years in 14 youngpatients. Acta Orthop Scand . 2002;73:432438.

33. Inan M, Bowen RJ. A pelvic support osteotomy and femorallengthening with monolateral fixator. Clin Orthop Relat Res .2005;440:192198.

34. Inan M, Alkan A, Harma A. Gluteal muscle after pelvic osteotomyto treat congenital dislocation of the hip. J Bone Joint Surg . 2005;87-A:22462252.

35. Gursu S, Demir B, Yildirim T, et al. The influence of aetiology of hip instability on the results of pelvic support osteotomy. Hip Int .2010;20:518523.

36. Krieg AH, Lenze U, Hasler CC. Ilizarov hip reconstructionwithout external fixation: a new technique. J Child Orthop . 2010;4:259266.

37. Thabet AM, Catagni MA, Guerreschi F. Total hip replace-ment fifteen years after pelvic support osteotomy (PSO): a casereport and review of the literature. Musculoskelet Surg . 2012;96:141147.

38. Bleck EE. Orthopaedic Management in Cerebral Palsy . London:Mac Keith Press; 1987.



18 recurrent dislocations and complete necrosis the.11

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