Femoral Lengthening in AchondroplasiaFemoral Lengthening in Achondroplasia

- Magnitude of lengthening versus Callus Feature, - Magnitude of lengthening versus Callus Feature, Stiffness of adjacent joints and fractureStiffness of adjacent joints and fracture

Prof. Hae Ryong SongProf. Hae Ryong SongDr .Ji Yeol YoonDr .Ji Yeol YoonDr. Jae Woo ChoDr. Jae Woo Cho

Department of orthopaedic surgery, Department of orthopaedic surgery, Institute of Rare Disease, Guro Hospital, Seoul, KoreaInstitute of Rare Disease, Guro Hospital, Seoul, Korea

Introduction Introduction Extensive limb lengthening Extensive limb lengthening more complications more complications

(Dahl MT et CORR1994) (Dahl MT et CORR1994) Joints stiffness and fracturesJoints stiffness and fractures

Fx. (20%) and knee joint stiffness (26%) Fx. (20%) and knee joint stiffness (26%)

Lengthened by 20% (Yun et al. JPO 2000)Lengthened by 20% (Yun et al. JPO 2000) Fx. (27%) and knee joint stiffness (65%) Fx. (27%) and knee joint stiffness (65%) :lengthened by 24% (Karger et al:lengthened by 24% (Karger et al66 CORR 1993) CORR 1993)

Materials and methodsMaterials and methods

40 femoral lengthening in achondroplasia40 femoral lengthening in achondroplasia Group A: less than 50% lengtheningGroup A: less than 50% lengthening Group B: more than 50% lengtheningGroup B: more than 50% lengthening

Comparison parametersComparison parameters Callus feature ; Ru Li classificationCallus feature ; Ru Li classification Hip and Knee stiffnessHip and Knee stiffness refracturerefracture

PARAMETERSPARAMETERS

Shape of callusShape of callus

Feature type of callusFeature type of callus

Density of callus using pixel valueDensity of callus using pixel value

fusiform cylindrical concave lateral central

Femoral Lengthening in Achondroplasia:Femoral Lengthening in Achondroplasia:

Magnitude of lengthening versus Magnitude of lengthening versus Callus Feature, Stiffness of adjacent joints and Fracture.Callus Feature, Stiffness of adjacent joints and Fracture.

Fusiform, cylinder, concave, lateral, central

Ru Li et alRu Li et al’’s classification of s classification of callus typescallus types

Pattern Low densityIntermediate density Normal density

SparseType 1 (soft)

Type 5 (half tone)

HomogeneousType 2 (stripe )

Type 6 (uniform)

Type 9 (solid)

HeterogeneousType 3 (speckle)

Type 7 (irregular)

Type 10 (cyst defects)

LucentType 4 (adjacent)

Type 8 (saw tooth)

RU- LI CLASSIFICATIONRU- LI CLASSIFICATION

A. Type 1 (sparse low density)A. Type 1 (sparse low density)

B. Type 2 (homogeneous low densityB. Type 2 (homogeneous low density

C. Type 3 (heterogeneous low density) C. Type 3 (heterogeneous low density)

D. Type 4 (lucent low density) D. Type 4 (lucent low density)

E. Type 5 (sparse intermediate density)E. Type 5 (sparse intermediate density)

Ru Li et al classification of callus as featureRu Li et al classification of callus as feature

F. Type 6 (homogeneous intermediate density) F. Type 6 (homogeneous intermediate density)

G. Type 7 (heterogeneous intermediate densityG. Type 7 (heterogeneous intermediate density

H. Type 8 (lucent intermediate densityH. Type 8 (lucent intermediate density

I . Type 9 (homogeneous normal densityI . Type 9 (homogeneous normal density

J. Type 10 (heterogeneous normal density)J. Type 10 (heterogeneous normal density)

Ru Li et al classification of callus as featureRu Li et al classification of callus as feature

Different pathways that the regenerate takes to matureDifferent pathways that the regenerate takes to mature

1. homogeneous pathway 1. homogeneous pathway

: type 2 → type 6 → type 9 : type 2 → type 6 → type 9

2. heterogeneous pathway 2. heterogeneous pathway

: type 3 → type 7 → type 10 : type 3 → type 7 → type 10

3.The lucent pathway3.The lucent pathway

: types 4 and 8: types 4 and 8

Hip flexion contracture and Hip flexion contracture and knee extension stiffnessknee extension stiffness

Callus features of regenerate fracture cases in femoral Callus features of regenerate fracture cases in femoral lengthening in achondroplasia.lengthening in achondroplasia.

Material and methodsMaterial and methods 28 cases of femoral lengthening in 14 patients,28 cases of femoral lengthening in 14 patients, 14 cases of callus fracture: 14 cases of callus fracture: mean lengthening; 9.4 cm, 41% (range 30-55%) mean lengthening; 9.4 cm, 41% (range 30-55%)

average timing of callus fracture at 15 months after surgery average timing of callus fracture at 15 months after surgery

14 case of without callus fracture 14 case of without callus fracture 9.1 cm, 30% 9.1 cm, 30%

Central shape callus -- Refracture after removal of fixation

Flexible nailing and bone grafting

Refracture after removal of fixation

Fixation with plate and bone grafting

Post op Postop 2 months

ConclusionConclusion

Fracture & Joint stiffness is a true complicationFracture & Joint stiffness is a true complication All Fx. : Lucent pathway (concave, lateral, atypical)All Fx. : Lucent pathway (concave, lateral, atypical) 30%↑ lengthening & 48%↑ reduction of callus width30%↑ lengthening & 48%↑ reduction of callus width

In our opinion, it is better to stop the distraction or to give In our opinion, it is better to stop the distraction or to give gradual compression distraction whenever there is occurrence gradual compression distraction whenever there is occurrence of concave, lateral and central shapes till the appearance of the of concave, lateral and central shapes till the appearance of the satisfactory regeneratesatisfactory regenerate