survivorship analysis of cemented total condylar knee arthroplasty. a long-term follow-up report on...

8/19/2019 Survivorship Analysis of Cemented Total Condylar Knee Arthroplasty. a Long-term Follow-up Report on 348 Cases

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T he J ou rna l o f A r t h rop l as t y V o l 11 N o 1 1996

S u r v i v o r s h i p n a l y s is o f C e m e n t e d T o ta l

C o n d y la r K n e e r t h r o p l a s ty

A L o n g te r m F o l l o w u p R e p o r t o n 3 4 8 C a se s

A d e l N a f e i , M D , O l e K r i s t e n s e n , M D , H a r a ld M o u s t g a a r d K n u d s e n , M D ,

I v a n H v i d , M D , P h D , a n d J o r n J e n s e n , M D

A b s t r a c t S u rv iv o r sh ip an a ly s i s w as u sed i n t h e ev a lu a t i o n o f 3 4 8 co n secu t iv e p r i -

m a r y t o t a l c o n d y l a r k n e e a r t h r o p l a s t i e s ( t o t a l k n e e a r t h r o p l a s t i e s ) p e r f o r m e d o n

2 5 3 p a t ie n t s i n a 2 7 - m o n t h p e r io d , w i t h a m a x i m u m f o l l o w - u p p e ri o d o f 1 2 y e a r s .

T h e d i ag n o s i s w as o s t eo a r th ro s i s i n 1 8 4 cases an d rh e u m ato id a r th r i t is i n 1 6 4 cases .

T en p a t i en t s (1 0 t o t a l k n ee a r th ro p l as t i e s ) w ere l o s t t o fo l l o w -u p ev a lu a t i o n . T h e

en d p o in t w as d e f in ed a s p ro s th es i s n o t in s i tu T h e v a r i ab l e s co n s id e red w ere ag e ,

sex , b o d y 1 T lass n d ex , an d d i ag n o si s . T h e o v e ra l l cu m u la t i v e su rv iv a l r a t e w as 9 2 .

T h e su rv iv a l r a t e o f t h e o s t eo a r th ro s i s g ro u p w a s s ig n if i can t ly h ig h e r (9 7 ) t h a n

th a t o f t h e rh e u m ato id a r th r i t i s g ro u p (8 7 ) . N o n e o f t h e o th e r v a r i ab l e s a f f ec t ed

surv ival ra te s ign if ican t ly . K e y w o r d s k n ee a r th ro p l as ty , k n ee p ro s th es i s , l o n g -

t e rm re su l ts , su rv iv o r sh ip an a ly s is , t o t a l co n d y la r k n ee .

T h e p r o s t h e s i s u s e d i n t h i s s t u d y i s a m o d i f i c a t i o n

( 5 ° p o s t e r i o r s l o p e o f t h e t i b i a l c o m p o n e n t ) o f t h e

o r i g in a l I n s a l l - B u r s t e i n p r o s t he s i s , w h i c h i s o f t h e

s e m i c o n s t r a i n e d , c r u d a t e l i g a m e m - s a c r i f i c i n g , c e -

m e n t e d t y p e w i t h o u t m e t a l b a ck i ng . S i n ce 1 97 9 t h e

p r o s th e s i s h a s b e e n u s e d i n o u r d e p a r t m e n t w h e n

t o t a l k n e e r e s u r f a c i n g a r t h r o p l a s t y w a s i n d i c a te d .

S e v e r a l a u t h o r s h a v e r e p o r t e d l o n g - t e r m s u r v i v a l

a n a l y s i s of t o t a l k n e e a r t h r o p l a s t y w i t h d i f f e re n t p r o s -

t h e t i c d e s i g ns . 1 4 F e w a u t h o r s h a v e r e p o r t e d l o n g -

t e r m s u r v i v a l a n a ly s i s o f t h i s d e si g n , a n d t h e n o n l y a s

s m a l l e r s u b g r o u p s o f l a r g e r h e t e r o g e n o u s s e r ie s . 4-6

T h i s s t u d y a i m e d t o e v a l u a t e t h e s u r v i v a l ra t e o f

a f a ir l y l a r ge c o n s e c u t i v e s e r i e s of t h e a b o v e - m e n -

t i o n e d p r o s t h e t i c d e s i gn , p e r f o r m e d a s a p r i m a r y

i n t e r v e n t i o n i n a s i ng l e c e n te r , a n d t o e v a l u a t e

s o m e o f t h e f a c t o r s t h a t m i g h t i n f l u e n c e t h e l o n g -

t e r m s u r v i v a l ra t e o f t h e p r o s t h e s e s .

From the Department of Orthopedic Surgery A arhu s University

Hospitals Aarhus Denmark.

Reprint requests: Adel Nafei MD Heriuf Trollesgade 7C st.

DK-8200 Aarhus N Denmark.

a t e r i a l s a n d e t h o d s

D u r i n g t h e p e r i o d O c t o b e r 1 9 7 9 t h r o u g h D e c e m -

b e r 1 9 8 2 , 3 4 8 c o n s e c u t i v e p r i m a r y t o t a l c o n d y l a r

k n e e a r t h ro p l a s ti e s ( TK A s ) w e r e p e r f o r m e d o n 2 5 3

p a t i e n t s . T h e d i a g n o s is w a s o s t e o a r t h r o s i s ( O A ) i n

1 8 4 ca s e s a n d r h e u m a t o i d a r t h r it i s ( R A ) in 1 6 4

c a s es . I n th e O A g r o u p , t h e r e w e r e 3 2 m e n ( 3 6

T IC A s) a n d 1 1 5 w o m e n ( 1 4 8 T K A s ) . I n t h e R A

g r o u p , t h e r e w e r e 2 1 m e n ( 3 3 T IC A s) a n d 8 5 w o m e n

( 1 3 1 T I C A s ) . M e d i a n a g e a t s u r g e r y w a s 7 0 y e a r s

( q u a rt i le s , 6 4 a n d 7 3 y e a r s ) in t h e O A g r o u p a n d 6 1

y e a r s ( q u a rt i le s , 5 0 a n d 6 8 y e a r s ) i n th e R A g r o u p .

T e n p a t i e n t s ( 1 0 TIC A s) w e r e l o s t t o f o l l o w - u p e v a l u -

a t i o n ( 5 T IC A s i n e a c h g r o u p ) . T h e i n d i c a t i o n f o r

k n e e a r t h r o p l a s t y in o u r d e p a r t m e n t i s c h r o n i c j o i n t

p a i n , d u e t o a d v a n c e d d e g e n e r a t i v e c h a n g e s i n v o l v -

i ng m o r e t h a n o n e j oi n t c o m p a r t m e n t .

T h e o p e r a t i n g t h e a t e r w a s e q u i p p e d w i t h l a m i -

n a r a ir f lo w . F i r s t - g e n e r a t i o n i n s t r u m e n t a t i o n w a s

u s e d f o r p r o s t h e s i s i m p l a n t a t i o n . 9 A l l s iz e s o f t h e

i m p l a n t w e r e a v a i l a b l e f o r u t i l iz a t i o n i n t h e p e r i o d

i n q u e s t i o n . W e r e s u r f a c e d t h e p a t e l l a i n a l l c a s e s .



8 T he J ou rna l o f A r t h rop l as t y Vo l 11 N o 1 J anu a ry 1996

T h e p ro s t h e t i c c o m p o n e n t s w e r e c e m e n t e d i n a ll

c a se s . A l l p a t i e n t s w e r e o p e r a t e d b y o r u n d e r

s u p e r v i s i o n o f t h e s a m e s e n i o r s u r g e o n . T h r e e

o t h e r s u r g e o n s w e r e i n v o l v e d . O p e r a t i v e t e c h n i c a l

g o a l s w e r e t o a c h i e v e a t i b i o f e m o r a l a l i g n m e n t

b e t w e e n 3 ° a n d 1 0 ° o f v al g u s , a n e u t r a l p o s i t i o n o f

t h e p r o s t h e t i c c o m p o n e n t s ( t il t < 5 °) , a r a n g e o f

m o t i o n g r e a t e r t h a n 9 5 ° , a n d a s ta b l e k n e e ( a m a x -

i m u m o f 5 ° i n s t a b i l i ty o n f u ll e x t e n s i o n ) .

P a t i e n ts w e r e e x a m i n e d c l in i c al l y a n d r a d i o g r a p h i -

c a l l y p r i o r t o s u r g e r y , i m m e d i a t e l y a f t e r s u r g e lT , 12

w e e k s a f t e r s u r g e ry , a n d a t o n e - y e a r i n t e r v a ls . T h e

k n e e r a t i n g s c o r e f r o m t h e H o s p i t a l f o r S p e c i a l

S u r ge r y ~0 w a s u s e d i n t h e e v a l u a t i o n s . T i b i o f e m o r a l

a l i g n m e n t b e f o r e a n d a f t er s u r g e r y a n d p o s i t i o n i n g

o f th e p r o s t h e t ic t i b i al c o m p o n e n t s a f te r s u r g e r y

w e r e a n a l y z e d in b o t h d i a g n o s t i c g r o u p s ( T a b le i ) .

F a i l u r e w a s d e f i n e d a s a p r o s t h e s i s w e r e a re v i -

s i o n o p e r a t i o n w a s p e r f o r m e d o r r e c o m m e n d e d .

T h e f a c t o r s c o n s i d e r e d w e r e d i a g n o s i s , a g e , s ex ,

a n d o b e s it y . A s f o r a g e , t h e p a t i e n t s w e r e s u b -

g r o u p e d i n t o t w o g r o u p s : a n e l d e r l y g r o u p ( > 6 0

y e a r s ) a n d a y o u n g e r g r o u p ( < 6 0 y e a r s ) . W e

d e f i n e d o b e s i t y a s a b o d y m a s s i n d e x ( B M I ) g r e a t e r

t h a n 2 7 u n i t s . B o d y m a s s i n d e x w a s c a l c u l a t ed

f r o m t h e p a t i e n t s ' b o d y w e i g h t i n k i lo g r a m s ( W )

a n d h e i g h t i n m e t e r s ( H ), w h e r e B M I = W / H 2, w i t h

a n o r m a l r a n g e b e t w e e n 2 I a n d 2 6 u n i t s . ~ T h e

m e d i a n B M I in t h e O A g r o u p w a s 2 8 u n it s ( q u a r -

t il e s, 2 5 a n d 3 0 ) , a n d i n t h e R A g r o u p i t w a s 2 4

u n i t s ( q u a r t i le s , 2 0 a n d 2 6 ) .

T h e p a t i e n t s i n t h e O A a n d R A g r o u p s w e r e s ig -

n i f i c a n t l y d i ff e r e n t f r o m e a c h o t h e r i n f o u r a s p e c t s

( M a n n - W h i t n e y U t e st ) :

A g e a t t i m e o f s u rg e r y ( m e d i a n a g e o f O A / R A

g r o u p s , 7 0 / 6 I y e a r s , P < .0 0 0 1 )

B o d y m a s s i n d e x ( m e d i a n B M I o f O A / R A

g r o u p s , 2 8 / 2 4 U , P < . 0 0 0 1 )

P r e o p e r a t i v e H o s p i t a l fo r S p e c i a l S u r g e r y s c o r e

( m e d i a n s c o r e o f O A / R A g r o u p s , 5 6 / 4 8 p o i n t s ,

P < . 0 0 0 1 ) .

P r e o p e r a t i v e d e v i a t i o n s f r o m t h e a c c e p t ab l e k n e e

a x i s b e t w e e n 3 ° a n d 1 0 ° of v a l g u s ( m e d i a n o f

d e v i a t i o n o f O A / R A g r o u p s , ] 0 o / 4 ° P <

. 0001 .

T h e r e f o r e , i t w a s n e c e s s a r y t o e x a m i n e t h e s u r v i v a l

r a t e s a n d t h e f a c t o r s t h a t m a y i n f l u e n c e t h e s e r a t e s

w i t h i n e a c h g r o u p s e p a r a t e l y .

T h e m e t h o d d e s c r i b e d b y A r m i t a g e 12 w a s

e m p l o y e d t o c o n s t r u c t s u r v i v o r s h i p t a b l e s. P a t i e n t s

w h o h a d d i e d o r w e r e l o st t o fo l l o w - u p e v a l u a t i o n

w e r e c e n s o r e d a c c o r d i n g t o t h e l a te s t a v a i l a b l e

a s s e s sm e n t . T h e l o g - r a n k t e s t w a s u s e d t o c o m p a r e

t h e c u m u l a t i v e s u r v i v a l r a te s o f t h e d i f f e r e n t

g r o u p s a n d s u b g r o u p s . O t h e r s t a t i s t i c a l t e s ts a r e

o t h e r w i s e s p e c if i e d . A P v a l u e l e s s t h a n . 05 w a s

c o n s i d e r e d s i g n i fi c a n t .

esu l t s

A t 1 2 y e a r s , t h e o v e r a l l c u m u l a t i v e s u r v i v a l r a te

w a s 9 2 . 3 ( 9 5 c o n f i d e n c e l i m i ts , 8 9 . 6 - 9 5 . 0 ) ,

w i t h a n a v e r a g e a n n u a l f a i l u r e r a t e o f 0 . 7 . T h e

s u r v i v a l c u r v e w i t h 9 5 c o n f i d e n c e l i m i t s f o r t h e

t o t a l m a t e r i a l i s s h o w n i n F i g u r e 1 . I n t h e O A

g r o u p t h e r e w e r e t h r e e f a i l u re s ( 2 c a se s o f l a t e

d e e p i n f e c t i o n a n d 1 c a s e o f m e c h a n i c a l l o o s e n -

T a b l e

1 . A S h o r t S t a t i s t i c a l R e p o r t o n t h e P r e - a n d

P o s t o p e r a t i v e K n e e A x i s a n d P o s i t i o n i n g o f

t h e

P r o s t h e t i c T i b i a l C o m p o n e n t i n t h e

T w o D i a g n o s t i c G r o u p s

P r e o p e r a t i v e P o s t o p e r a t i v e

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Y E A R S A F T E R O P E R A T I O N

F i g . 1 . C u m u l a t i v e s u r v i v a l r a t e o f t h e t o t a l m a t e r i a l .

H a t c h e d a r e a r e p r e s e n t s 9 5 c o n f i d e n c e l i m i ts .



i n g ) . T h e c u m u l a t i v e s u c c e s s r a t e o f t h e O A g r o u p

w a s 9 7 ( 9 5 c o n f i d e n c e l i m i ts , 9 4 . 7 - 9 9 . 5 ) , w i t h

a n a v e r a g e a n n u a l f a i l u r e r a t e o f 0 . 3 .

I n t h e R A g r o u p , t h e r e w e r e 1 3 f a i l u r e s ( 5 c a s e s

o f l a t e d e e p i n f e c t i o n , 6 c a s es o f m e c h a n i c a l l o o s -

e n i n g , a n d 2 c as e s o f t r a u m a t i c l o o s e n i n g ) . T h e

c u m u l a t i v e s u c c e s s r a t e i n t h e R A g r o u p w a s 8 7

( 9 5 c o n f i d e n c e l i m i ts , 8 2 . 2 - 9 1 . 8 ) , w i t h a n a v e r -

a g e a n n u a l f a i l u r e ra t e of 1 .2 .

T h e c u m u l a t i v e s u r v i v a l r a t e o f t h e O A g r o u p

w a s s i g n i f i c a n t ly h i g h e r t h a n t h a t o f t h e R A g r o u p

( F ig . 2 , P = .0 0 5 ) . N o n e o f t h e o t h e r v a r i a b l e s ( a g e ,

s e x , B M I ) h a d a s t a t i s t ic a l l y s i g n i f i c a n t e f f e c t o n

s u r v i v a l r a t e . A s u m m a r y o f t h e c u m u l a t i v e s u r -

v i v a l r a t e s i n r e l a t i o n t o t h e o t h e r f a c t o rs c o n s i d -

e r e d i n b o t h d i a g n o s t i c g r o u p s i s g i v e n i n T a b l e 2 .

i s cuss ion

I n p r o s t h e t i c k n e e r e c o n s t r u c t i o n , w h e r e t h e

m a i n i n d i c a t i o n is d e g e n e r a t i v e c h r o n i c p a i n , t h e

l o g i ca l c h o i c e o f t h e e n d p o i n t m u s t b e w h e n a

p a t i e n t h a s p a i n ; t h a t i s , a p r o s t h e t i c l i fe s p a n

w o u l d b e a p a i n - t o - p a i n c y c l e .

S o m e a u t h o r s c h o o s e p r o s t h e t i c r e v i s i o n a s t h e

e n d p oi n tl ,2 , 5, 6 ; o t h e r s a d d s e v e r e p a i n ( w i t h o u t

r e v i s i o n ) t o t h e r e v i s i o n c r i t e r i a a s a n e n d p o i n t d e f -

i n i t i o n . 8 O t h e r a u t h o r s a n a l y z e t h e i r m a t e r i a l s

a c c o r d i n g t o a v a r i e t y o f e n d p o i n t s . 4 , 7,13 W e p r e f e r

t o a p p l y r e v i s i o n a s t h e e n d p o i n t , a s it i s a c l e a r - c u t

a n d a c o m p a r a b l e c r i te r i on , w h i c h i s i n d e p e n d e n t

o f s u b j e c ti v i t y , a n d i t i s b a s e d p r e d o m i n a n t l y o n a

p a t i e n t ' s i n t r a c t a b l e r e s i d u a l p a i n . R a d i o g r a p h s a t

t h e t i m e o f d e c i s i o n m a k i n g f o r r e v i s i o n w i l l s u p -

p o r t t h e s u r g e o n ' s d e c i s i o n , as r a d i o l u c e n t z o n e s

c o r r e l a t e w i t h r e s i d u a l p a i n i n t e n s i t y , as w e

s h o w e d e a r l i e r . 1 4 , 1 5

S urv i v o rs h i p A na l y s i s o f T K A • N a f e i e t a l 9

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Y E A R S A F T E R O P E R A T I O N

F i g . 2 . C u m u l a t i v e s u r v i v a l r a t e s o f th e o s t e o a r t h r o s i s

( O A ) a n d t h e r h e u m a t o i d a r t h r i ti s ( R A ) g r o u p s . H a t c h e d

a r e a s r e p r e s e n t 9 5 c o n f i d e n c e li m i t s . P = .0 0 5 .

T h e o v e r a l l c u m u l a t i v e r a t e s o f s u r v i v a l i n th i s

s e r i e s ( 9 8 a t 5 y e a r s , 9 2 a t 1 2 y e a r s ) c o i n c i d e

w i t h t h o s e r e p o r t e d b y o t h e r a u t h o rs . 4 , 6 T h e c o m -

p a r i s o n w i t h o t h e r m a t e r i a l i s o f t e n w e a k e n e d b y

t h e f a c t t h a t o n l y f e w a u t h o r s r e p o r t t h e i r s u r v i v a l

r a te s a c c o m p a n i e d b y c o n f i d e n c e l i m i t s .

T h e m o s t p r o m i n e n t f e a t u r e o f t h i s s t u d y ' s

r e s u l ts i s t h e s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e

s u r v i v a l r a t e s o f t h e t w o d i a g n o s t i c g r o u p s , w h i c h

c o n f li c t s w i t h e a r l i e r r e p o r t s . R a n d a n d I l s t r u p

f o u n d t h a t t h e d i a g n o s i s o f R A w a s a v a r i a b l e

f a v o r i n g a h i g h o v e r a l l s u c c e ss r a t e w h e n t h e

w h o l e g r o u p w a s c o n s i d e r e d ( d i f f e r e n t t y p e s of

T a b l e 2 . T w e l v e - y e a r C u m u l a t i v e S u r v i v a l R a t e s o f t h e T w o D i a g n o s t i c G r o u p s

a s a F u n c t i o n o f D i f f e r e n t V a r i a b l e s

O s t e o a r t h r o s i s

G r o u p R h e u m a t o i d A r t h r i t is G r o u p

Var iab le n CSR CL n CSR CL

Age (years)

> 60 157 97.3 94.6-10 0 84 91.6 85.8-9 7.4

_< 60 27 100 - - 80 90.5 8 3.1-97 .9

Sex

Men 36 100 - - 33 81 .0 68 .2 -93 .8

W om en 148 96.5 93.6-9 9.4 131 90.4 85.6-95 .2

B o d y m a s s i n d e x

> 27 94 98.9 96.8-10 0 30 96.7 90.4-1 00

_< 27 90 95.2 90.9 -99.5 134 85.6 80.0 -91 .2

n , numb er o f cases in the subgroup ; CSR, cumu la t ive su rv iva l ra te ( ) a t 12 yea rs ; CL , 95 conf idence

limits .



1

The Journa l o f Ar th rop las ty Vo l 11 No 1 Janu ary 1996

prostheses). 5 Nevertheless, wh en they considered

the 5-year survival probability of a prosthetic

design similar to the one used in our series, they

found no significant difference. Several other stud-

ies concluded that the diagnosis did not affect sur-

vival rates. 2,6A6 In ou r earlier repo rts on the same

prosthesis using the traditional case follow-up

method of assessment, we found no significant dif-

ference in outcome between the OA and RA

groups, only tendencies toward a better outcome

in the OA group.15,17-21 Nevertheless, when the

survivorship method of analysis was applied, the

OA group proved to have a significantly better out-

come than the RA group. This controversy con-

cerning the significance of the diagnosis on the

prosthetic survival rate and our finding of signifi-

cant differences between the two diagnostic groups

age, BMI, preoperative Hospital for Special

Surgery score, and preoperative alignment)

strongly suggest that investigators must stratify

their material according to the diagnosis.

In the present series no significant difference was

found between the survival rates of younger and

elderly patients within the diagnostic groups. The

findings re porte d by Ritter et a1.13 and Ran d a nd

Ilstrup 5 conc erni ng th e effect of age o n prost hesis

survival must be cautiously interpreted, as their

material was analyzed irrespective of the diagnosis.

For the purpose of comparability, we emphasize

the importance of stratified analysis and presenta-

tion of confidence limits and data about implant

positioning. Revision opera tion is the mos t suitable

endpoin t to apply.

cknowledgment

The authors thank Soren M. Bentzen, DMSc,

PhD, Institute of Cancer Research, Aarhus Univer-

sity, for his participation in the statistical analysis of

this work.

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