Guided Growth for the Correction of Pediatric Lower Limb Angular Deformitydr Michael John T Pembimbing : dr Muh Andry Usman, SpOT

IntroductionGuided growth (ie, growth manipulation) is a

useful technique to correct angular deformities in children. Using either temporary or permanent hemiepiphysiodesis. Function by tethering one side of a growing physis allowing for differential growth. Common problems are undercorrection and overcorrection.

IntroductionGuided growth is most commonly used to

address coronal plane deformity about the knee. Guided growth can be used to manage deformity in any plane on any extremity.

History of Growth ManipulationOsteotomy is the most common technique for

correction of angular deformity of a limb.

Etiology of Angular Deformity

Indications for Correction of DeformityStudies have shown that there is an

association between varus and valgus malalignment of the knee and osteoarthritis (OA). No evidence showed that malalignment caused the OA. Evidence suggested that malalignment maybe contribute to the development of knee OA.

Biomechanical and gait studiesVarus alignment increases medial load during

gait. Valgus alignment is associated with increases in lateral compartment peak pressures, and that. Varus and valgus malalignment increase medial and lateral load.10-13

Indications for Correction of DeformityThe risk of OA is often cited as a reason to

consider management of angular lower extremity malalignment. Primary indication for guided growth is a clinically unacceptable deformity in a patient with open physes. Sagittal plane deformity is more likely to produce functional impairment than coronal plane abnormality.

Indications for Correction of DeformityOther indications include impairment

producing deformity and a physis with adequate growth remaining (approximately 1 year) to allow correction.15

Preoperative AssessmentThe deformity can be diagnosed based on the

patient history, physical examination, and radiographic imaging. The physical examination assess the limb length, coronal and sagittal alignment in the standing position and static and dynamic knee stability (ie, lateral thrust).

Preoperative AssessmentThe preferred radiographic view for

assessment of lower extremity deformity is a standing film that includes the hip and the ankle.

Determining the amount of growth remainingBefore performing hemiepiphysiodesis,

determine skeletal age by comparing a radiograph of the left hand to the standards published by Greulich and Pyle.16 There is also clinical parameters such as the Tanner stages and onset of menses. Radiographs of the elbow and pelvis

Timing of HemiepiphysiodesisEstimating remaining growth based on skeletal

age is an inexact process because the health of the physis must be considered too. Several conditions are associated with abnormal physeal growth : skeletal dysplasias, trauma, and irradiation. It will leads to slower correction.

compression and tension forces at the physis

can cause physeal growth inhibition and acceleration (The Heuter-Volkmann principle)

Temporary (ie, reversible) hemiepiphysiodesis

is an option in younger patients. Once angular correction has been achieved, the tethering device (ie, staple, screw, plate) may be removed. Response of the physis is unpredictable. Recurrence of deformity called rebound effect (ie, accelerated growth on the side of the physis that was temporarily restrained) is common.

Delaying removal of the tethering implants

until a small amount (5) of overcorrection has occurred. The tethered side of the physis may close before the untethered side.7 A contralateral hemiepiphysiodesis of the untethered side may be required to prevent permanent overcorrection.

For patients who are near skeletal maturity,

permanent hemiepiphysiodesis is an option because it eliminates the possibility of implant- related complications and the unpredictability associated with the rebound effect. Correct timing is necessary.

Timing of Hemiepiphysiodesis

Temporary Hemiepiphysiodesis StaplesFirst described by Blount and Clarke in 1949 Under fluoroscopic guidance, three staples are

used to span the physis The entire procedure is extraperiosteal. Care must be taken to avoid damaging the physis or the zone of Ranvier permanent hemiepiphysiodesis.

StaplesBe Careful of rebound growth Average of 5 (2 - 11) in 22 patients of 35

patients. Overcorrection of approximately 5 was recommended for patients with significant growth remaining.

Temporary Hemiepiphysiodesis ScrewsIn 1998, Mtaizeau et al described a new

technique for percutaneous epiphysiodesis using transphyseal screws. With average of 7 (4 - 12) of genu valgum correction within 3 of anatomic mechanical alignment (9 patients) Average of 12.5 of correction by 2.6 years using percutaneous epiphysiodesis with transphyseal screws in 18 knees with an average initial angular deformity of 18 (Nouh and Kuo)

ScrewsA major criticism of this study was the mild

initial deformity. However, other studies have confirmed the validity of this technique in patients with greater deformity.

Temporary Hemiepiphysiodesis Tension Band PlateAssociated with the use of staples there are

concerns regarding implant breakage and migration, also the potential for physeal arrest Stevens used this plate in 34 patients. A 30% higher rate of correction was reported with plating than with staples. All patients achieved full correction. No premature physeal arrests were reported.

Tension Band PlateFour patients aged 1 cm resulted in a prominent fibular head. Recommended fibular epiphysiodesis when overgrowth is expected to exceed 1-2 cm.

ComplicationsComplications associated with guided growth

can be classified as :Physiologic (eg, infection, swelling, stiffness) Hardware-related (eg, implant extrusion,

breakage, prominence) Growth-related (eg, undercorrection, overcorrection, permanent physeal injury)

THANK YOU

References1. Phemister DB: Operative arrestment of

longitudinal growth of bones in the treatment of deformities. J Bone Joint Surg Am 1933;15:1-15. 2. Bowen JR, Leahey JL, Zhang ZH,MacEwen GD: Partial epiphysiodesis at the knee to correct angular deformity.Clin Orthop Relat Res 1985;198:184-190 3. Venable CS, Stuck WG, Beach A: The effects on bone of the presence of metals; based upon electrolysis: An experimental study. Ann Surg 1937;105(6):917-938.

References4. Haas SL: Retardation of bone growth by a

wire loop. J Bone Joint Surg Am 1945; 27:2536. 5. Haas SL: Mechanical retardation of bone growth. J Bone Joint Surg Am 1948;30(2):506512. 6. Blount WP, Clarke GR: Control of bone growth by epiphyseal stapling: A preliminary report. J Bone Joint Surg Am 1949;31(3):464478.

References7. Zuege RC, Kempken TG, Blount WP:

Epiphyseal stapling for angular deformity at the knee. J Bone Joint Surg Am 1979;61(3):320-329. 8. Mtaizeau JP, Wong-Chung J, Bertrand H, Pasquier P: Percutaneous epiphysiodesis using transphyseal screws (PETS). J Pediatr Orthop 1998;18(3):363-369. 9. Stevens PM: Guided growth for angular correction: A preliminary series using a tension band plate. J Pediatr Orthop 2007;27(3):253-259.

References10.Morrison JB: The mechanics of the knee

joint in relation to normal walking. J Biomech 1970;3(1):51-61. 11. Bruns J, Volkmer M, Luessenhop S: Pressure distribution at the knee joint: Influence of varus and valgus deviation without and with ligament dissection. Arch Orthop Trauma Surg 1993;113(1):12-19. 12. Tetsworth K, Paley D: Malalignment and degenerative arthropathy. Orthop Clin North Am 1994;25(3):367-377.