Francisco Angulo Parker, MDPGY3UKY PM&R

KNEE HYPEREXTENSION AFTER HAMSTRING LENGTHENING IN

CEREBRAL PALSY: INCIDENCE, PREDICTIVE FACTORS AND

COST IN GAIT EFFICIENCY

CEREBRAL PALSY

Cerebral palsy (CP) is the leading cause of childhood disability aff ecting function & development

Overall estimated prevalence of CP is 2-2.5 cases per 1000 live births

Criteria for CP: Static Brain lesion Neuro-motor control deficit that affects movement or

posture Immature brain

HAMSTRING LENGTHENING

Goal of surgery in ambulatory patients

To improve gait

effi ciency

To improve knee

flexion deformity

To increase knee

extension at the end of

swing phase and at

heel strike

Crouching gait

DESCRIPTIVE STATISTICS

No. (%)

Gender

Male 97 (66%)

Female 50 (34%)

GMFCS 1 26 (17.7%)

GMFCS 2 48 (32.7%)

GMFCS 3 73 (49.7%)

Mean(std)

Age at surgery 12. 1 (3.2) years

Duration b/w surgery & post op gait analysis

1.4 (1.1) years

KINEMATICS IN GAIT EFFICIENCYPOOR DATA PREDICTING KNEE HYPEREXTENSIONREGARDED AS POOR OUTCOMEAVAILABILITY OF DATABASESERIES OF STUDIES FROM SAME DATABASE

BACKGROUND

Incidence

Can we predict it? What are the predictive variables?

Cost of knee hyperextension in gait effi ciency

OBJECTIVES

Retrospective, case control study.

Regression analysis for predicting variables.

METHODOLOGY

POPULATION

Diagnosis Frequency

CP hemiplegia 2

CP diplegia 142

HSP 5

parplegia 3

fredrichs ataxia 1

Total 153

POPULATION

Characteristics

Gender 93 males 49 female

Previous Hamstring No: 110 Yes: 32

POPULATION

Procedures

33 only HS lengthening34 TAL and HS lengthening30 Rectus transfer and HS lengthening27 TAL, HS lengthening and rectus transfer

POPULATION

284 knees (142 patients)

Hyperextension considered 0 deg and above pass full extension

11.5% of the knees showed hyperextension post HS lengthening

INCIDENCE OF KNEE HYPEREXTENSION

Preop GMFCSLevel Age at surgery Other simultaneous surgery (yes/no) Simultaneous RECTUS (yes/no) Preop L Popliteal angle Preop L Knee extension Preop L Knee fl exor tone Preop L hip extensor Preop L knee Flexor Preop L knee Extensor PRE L 0 = knee fl exion at initial contact preop PRE L 30 = knee fl exion at mid-stance preop Change HT change in height from preop to post op Change WT change in weight from preop to post op

VARIABLE ANALYSIS FOR PREDICTION

Variables in the Equation

  B S.E. Wald df Sig. Exp(B)

Step 1a

preGMFCSLevel 1.027 .424 5.854 1 .016 2.793

age_atsurgery -.131 .087 2.262 1 .133 .877

othersimultaneoussurgery -.253 .199 1.620 1 .203 .776

simultaneous_RECTUS .316 .614 .266 1 .606 1.372

Preop__Popliteal_angle .057 .027 4.533 1 .033 1.059

Preop__Knee_extension .013 .039 .114 1 .736 1.013

Pre_op__Knee_flexor_tone .382 .273 1.966 1 .161 1.466

Pre_op__hip_extesor_contr

ol.310 .196 2.516 1 .113 1.364

Pre_op__knee_Flexor_cont

rol.024 .241 .010 1 .921 1.024

Pre_op__knee_Extensor_c

ontrol-.476 .345 1.906 1 .167 .622

PRE__0 -.049 .027 3.225 1 .073 .953

PRE__30 -.046 .023 4.070 1 .044 .955

changeHT .009 .040 .053 1 .818 1.009

changeWT .034 .037 .861 1 .354 1.035

timetofollowup -.060 .164 .134 1 .715 .942

Constant -1.339 3.043 .194 1 .660 .262

VARIABLES

Statistically significant P=<0.05 Pre GMFCS Pre op angle Pre operative knee flexion at midstance

Clinically significant Significant results only present in Pre operative knee

flexion at midstance

VARIABLE ANALYSIS FOR PREDICTION

GAIT

Stance phase (1) Limb of interest in contact

with ground 60% of gait when walking

Heel strike loading response - foot plantar

flexes to ground midstance - tibia shifts

forward over plantigrade foot terminal stance – heel rise preswing

Swing phase (1) Limb of interest in air 40% of gait when walking

Initial swing – begins with toe off , limb moves forward

Midswing – when limb passes grounded limb

Terminal swing – also known as deceleration, slow down towards heel strike

Pre-operative knee flexion at midstance

Not hyperextended. Mean: 35.451 SD: 16.2

Hyperextended Mean: 23.9 SD: 17.59

RESULTS

Measured by Oxygen consumption pre and post bilateral hamstring lengthening

Same database

 Only 78 subjects with preop and post op oxygen consumption data

GAIT EFFICIENCY

Oxygen consumption

Amount of oxygen consumed per kg of body weight over time (mL/kg-min)

Total power required to keep the body in motion

Related to the level of effort it takes to walk Does not take walking velocity into account

GAIT EFFICIENCY

Group Statistics

  post_Hyper_R N Mean Std. Deviation Std. Error Mean

PreO2ConsumptionExercisenot hyper 69 18.938 3.8794 .4670

hyper 9 19.422 3.2468 1.0823

Pre02Costnot hyper 69 .6293 .30379 .03657

hyper 9 .7344 .24895 .08298

PostO2ConsumptionExercisenot hyper 69 17.233 3.4472 .4150

hyper 9 17.722 4.1176 1.3725

Post02Costnot hyper 69 .5419 .19304 .02324

hyper 9 .6233 .20062 .06687

Change_O2_costnot hyper 69 -.0874 .21070 .02536

hyper 9 -.1111 .12830 .04277

Change_O2_Consumnot hyper 69 -1.7043 3.97937 .47906

hyper 9 -1.7000 2.73359 .91120

RESULTS

Incidence of knee hyperextension after hamstring lengthening in our population is 11.5%

Significant variable: knee flexion at midstance

Statistical and clinical significance at a mean of 23.9 degrees when compared to a mean of 35.4 degrees

No significant change in Oxygen consumption in hyperextended vs non-hyperextended knees

CONCLUSION

Clinical follow up at 1.5 years after surgery. Long term observance should be considered

Insufficient knee flexion at midstance would bring up the incidence to approximately 25%

What is the efficiency cost in chronic knee hyperextension?

Overall, the prediction of hyperextension continues to be difficult

DISCUSSION

1. H e r r i n g JA , Ta c h d j i a n M O. Tex a s S c o t t i s h R i t e H o s p i t a l f o r C h i l d re n . Ta c h d j i a n ’ s Pe d i a t r i c O r t h o p a e d i c s . 4 t h E d i t i o n . P h i l a d e l p h i a : S a u n d e r s / E l s e v i e r ; 2 0 0 8

2. Ro s e n b a u m P , Pa n e t h N , Le v i t o n A , e t a l . A re p o r t : t h e d e fi n i t i o n a n d c l a s s i fi c a t i o n o f c e re b r a l p a l s y. D e v M e d C h i l d N e u ro l S u p p l . 2 0 0 7 ; 1 0 9 : 8 – 1 4 .

3. G o rd o n A B , B a i rd G O , M c M u l k i n M L , C a s ke y P M , Fe rg u s o n R L . G a i t a n a l y s i s o u t c o m e s o f p e rc u t a n e o u s m e d i a l h a m s t r i n g t e n o t o m i e s i n c h i l d re n w i t h c e re b r a l p a l s y. J o u rn a l o f Pe d i a t r i c O r t h o p a e d i c s 2 0 0 8 ; 2 8 ( 3 ) : 3 2 4 – 9 .

4. U n n i t h a n V B , D o w l i n g J J , Fro s t G , B a r- O r O. ( 1 9 9 9 ) Ro l e o f m e c h a n i c a l p o w e r e s t i m a t e s i n t h e O 2 c o s t o f w a l k i n g i n c h i l d re n w i t h c e re b r a l p a l s y. M e d S c i S p o r t s E x e r 3 1 : 1 7 0 3 – 1 7 0 8 .

5. C a n a l e S T , B e a t y J H . C a m p b e l l ’ s O p e r a t i v e O r t h o p a e d i c s . 1 1 t h E d i t i o n . Ac c e s s e d O n l i n e . 6. D h a w l i ka r S H, Ro o t L, M a n n R L. D i s t a l l e n g t h e n i n g o f t h e h a m s t r i n g s i n p a t i e n t s w h o h a v e c e re b r a l

p a l s y. Lo n g - t e rm re t ro s p e c t i v e a n a l y s i s . J B o n e J o i n t S u rg A m . 1 9 9 2 O c t ; 7 4 ( 9 ) : 1 3 8 5 - 9 1 .7. S . L . D e l p , A . S . A rn o l d , R . A . S p e e r s , a n d C . A . M o o re , " H a m s t r i n g s a n d p s o a s l e n g t h s d u r i n g n o rm a l

a n d c ro u c h g a i t : i m p l i c a t i o n s f o r m u s c l e - t e n d o n s u rg e r y , " J o u r n a l o f O r t h o p a e d i c R e s e a r c h , v o l . 1 4 , p p . 1 4 4 - 1 5 1 , 1 9 9 6 .

8. D e Lu c a P , O u n p u u O , D a v i s R B , Wa l s h J : E ff e c t o f h a m s t r i n g s a n d p s o a s l e n g t h e n i n g o n p e l v i c t i l t i n p a t i e n t s w i t h s p a s t i c d i p l e g i c c e re b r a l p a l s y. J o u r n a l o f P e d i a t r i c O r t h o p a e d i c s 1 9 9 8 , 1 8 : 7 1 2 - 7 1 8 .

9. G a g e J R , N o v a c h e c k T F. ( 2 0 0 1 ) A n u p d a t e o n t h e t re a t m e n t o f g a i t p ro b l e m s i n c e re b r a l p a l s y. J P e d i a t r O r t h o p B 1 0 : 2 6 5 – 2 7 4 .

10. B . T. C a rn e y , D . O e ffi n g e r a n d A . M . M e o , S a g i t t a l k n e e k i n e m a t i c s a f t e r h a m s t r i n g l e n g t h e n i n g , J P e d i a t r O r t h o p B 15 ( 5 ) ( 2 0 0 6 ) , p p . 3 4 8 – 3 5 0 .

11. J . R . G a g e a n d T. F. N o v a c h e c k , A n u p d a t e o n t h e t re a t m e n t o f g a i t p ro b l e m s i n c e re b r a l Pa l s y , J P e d i a t r O r t h o p 10 ( Pa r t B ) ( 2 0 0 1 ) , p p . 2 6 5 – 2 7 4

12. Pa l i s a n o R , Ro s e n b a u m P , Wa l t e r S , Ru s s e l l D , Wo o d E , G a l a p p i B . ( 1 9 9 7 ) D e v e l o p m e n t a n d re l i a b i l i t y o f a s y s t e m t o c l a s s i f y g ro s s m o t o r f u n c t i o n i n c h i l d re n w i t h c e re b r a l p a l s y. D e v M e d C h i l d N e u r o l 3 9 : 2 1 4 –2 2 3 .

13. C h a n g W N , Ts i r i ko s A I , M i l l e r F M , Le n n o n N , S c h u y l e r J , Ke r s t e t t e r L , G l u t t i n g J , . D i s t a l H a m s t r i n g Le n g t h e n i n g i n a m b u l a t o r y c h i l d re n w i t h C e re b r a l p a l s y: p r i m a r y v e r s u s re v i s i o n p ro c e d u re s . G a i t a n d Po s t u re . ( 2 0 0 4 ) 1 9 : 2 9 8 - 3 0 4

14. S c h w a r t z M H , V i e h w e g e r E , S t o u t J , N o v a c h e c k T F , G a g e J R . C o m p re h e n s i v e t re a t m e n t o f a m b u l a t o r y c h i l d re n w i t h c e re b r a l p a l s y: a n o u t c o m e a s s e s s m e n t . J o u rn a l o f Pe d i a t r i c O r t h o p e d i c s 2 0 0 4 ; 2 4 : 4 5 – 5 3 .

REFERENCES