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The palmar abduction-pronation osteotomy of the firstmetacarpal bone combined with tendon transfer for lateral thenar muscle paralysis
The Pahnar A bduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
T H E P A L M A R A B D U C T I O N - P R O N A T I O N O S T E O T O M Y OF T H E FIRST M E T A C A R P A L B O N E C O M B I N E D W I T H T E N D O N T R A N S F E R FOR LATERAL THENAR MUSCLE PARALYSIS
J. J. C O M T E T and D. BEMELMANS, Lyon, France SUMMARY The authors describe a palmar abduction-pronationosteotomy of the first metacarpal bone combined with a tendon transfer for treatment of palsy of the lateral thenar muscles. The results of fourteen cases are reported. INTRODUCTION
The lateral thenar muscles (abductor pollicis brevis, opponens and flexor pollicis brevis) are responsible for the movements of palmar abduction and axial rotation (pronation) o f thumb column as well as some degree of adduction. Those muscles therefore play a fundamental role in opposing the thumb to the other fingers, (Duchenne, 1867; Kaplan, 1965; Kapandji, 1972). The palliative treatment of thenar muscle paralysis necessitates a tendon transfer. The different varieties of procedure are so numerous that it is difficult to report on them all, but their common principles were established by Bunnell (1924), Boyes (1964) Tubiana (1969). Other authors thought of acting on the thumb's skeleton either by fixation of the first metacarpal in opposition with a carpo-metacarpal arthrodesis (Foerster, 1930) or by an inlay bone graft on the anterior aspect of the first metacarpal bone to improve the lever action of the tendon transfer. (Le Coeur, 1953), (Fig lb). The aim of this work is to describe the technique and results of a method of palmar abduction-pronation osteotomy of the first metacarpal bone associated with a tendon transfer. CLINICAL MATERIAL Fifteen patients (eleven males, four females) were operated on by his new osteotomy technique. The average age was thirty-two years. The median nerve paralysis was due in thirteen cases to a wound with nerve injury. In one case it was due to a partial brachial plexus injury and in one case to congenital atrophy of the thenar muscles. Fourteen of the fifteen patients were followed up for two to five years with an average follow-up o f two and a half years. All the patients were subjected, before surgical intervention, to a thorough clinical examination of the hand, and electromyography, confirming the complete denervation of the thenar muscles, was always carried out. In addition to the paralysis, several of the patients had stiffness of the trapeziometacarpal joint in supination position of the thumb. SURGICAL TECHNIQUE All operations were carried out under general anaesthesia or brachialplexus block. A clear field was ensured by a pneumatic tourniquet. Pr Ag J. J. Comtet, Hfpital Edouard Herriot, Pavillon T, 69 374 Lyon Cedex 2, France. The Hand--Volume 11
No. 2.
1979
191
The Palmar A bduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 1. a. Lever action of a single transfer b. Lever action of a transfer with ale Coeur-type bone graft c. Lever action of a transfer with palmar abduction pronation osteotomy.
The skin incision extends from the trapezio-metacarpal joint to the proximal third of the second phalanx of the thumb. The slightly sinuous incision therefore passes along the outer border of the thenar eminence, allowing proper access to the first metacarpal bone and the extensor tendons. The periosteum of the first metacarpal is incised longitudinally, anterior to the extensor pollicis brevis, and elevated circumferentially, thus liberating the shaft from the muscular insertions. This is a very important step to allow rotation. Osteotomy is performed at the junction between the base and shaft in a zone of cancellous bone, allowing impaction and facilitating union. The osteotomy is first prepared by multiple holes of 2 mm in diameter and then completed by an osteotome. (Fig. 3). The distal part of the thumb is then placed in the axis of the middle finger in a palmar abduction and pronation, so that the distance between its pulp and the midcrease of the palm is fifty millimetres and its dorsal (nail) aspect is at a 135 ~ angle to the palm. The necessary angle of rotation varies from 60 ~ to 120 ~ according to each individual case. Fixation is provided by two Kirschner wires of 1.6 mm diameter : one is passed longitudinally through the distal metacarpal fragment, its point penetrating just far enough into the carpal bone, and the other one is introduced from the proximal to~ the distal fragment. (Fig. 4). Tendon transfer is then carried out according to Zancolli's modification of Tubiana's technique, using the tendon o f extensor pollicis brevis divided at its distal insertion, with the flexor carpi radialis as a pulley. It is reinserted into the tendon of the abductor pollicis brevis. (Fig. 2). In two cases the tendon of extensor pollicis brevis was so thin that we used instead the tendon o f the flexor digitorum superficialis of the ring finger. 192
The H a n d - - Volume 11
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The Palmar A b duction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
EZz3U: Fig. 2. Osteotomy of the first metacarpal bone with transfer of the extensor pollicis brevis. 1) Abductor pol|icis brevis 2) Extensor potlicis brevis 3) Flexor carpi radialis C l o s u r e is then c a r r i e d o u t in one l a y e r , a n d plaster cast i m m o b i l i s a t i o n lasts for three weeks. T h e K i r s c h n e r wires are w i t h d r a w n after a c o n t r o l X - r a y a r o u n d the sixth week. POSTOPERATIVE EVALUATION T h e criteria used in p o s t o p e r a t i v e e v a l u a t i o n were the following: 1. P a l m a r a b d u c t i o n , m e a s u r e d b y the vertical distance b e t w e e n the tip o f t h e t h u m b a n d the m i d c r e a s e o f the p a l m . 2. R o t a t i o n ( p r o n a t i o n ) is difficult to e v a l u a t e even using t h e " m a t c h e s m e t h o d " o f
,\
C3 Fig. 3. a,b,c, Surgical technique of the palmar-abduction pronation osteotomy. The Hand--Volume 11
No. 2.
1979
193
The Palmar Abduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 4. Fixation is ensured by two Kirschner wires. Note the impacted fragments. Fig. 5. Preoperative view showing atrophy of the thenar muscles and absences of abduction and pronation of the thumb. Fig. 6. This post-operative of the same hand shows for comparison the palmar abduction and pronation of the thumb. Bunnell. W e assess it by l o o k i n g at the h a n d f r o m its distal end in the axis o f the fingers. W e o b s e r v e the progressive h o r i z o n t a l p o s i t i o n o f the t h u m b nail, when the latter is o p p o s e d f r o m the index to the little finger. R o t a t i o n is m e a s u r e d in o p p o s i t i o n to the m i d d l e finger, being the angle f o r m e d between the nail p l a n e a n d the p a l m a r p l a n e . This is a difficult m e a s u r e m e n t , b e c a u s e the m a r g i n o f e r r o r can be as high as 20 ~ , so we express it as follows: + 5 0 ~ + + 5 0 ~ to 90 ~ + + + 9 0 ~ to 120 ~ 3. T i p t o T i p o p p o s i t i o n where the p u l p o f the t h u m b t o u c h e s the p u l p o f the o t h e r fingers. This s h o u l d be d i s t i n g u i s h e d f r o m o p p o s i t i o n to o t h e r p a l m a r parts o f the fingers especially to the base o f the little finger. 4. E . M . G . E l e c t r o m y o g r a p h y later helps to p r o v e t h a t the f u n c t i o n a l i m p r o v e m e n t is n o t d u e to a d e l a y e d r e i n n e r v a t i o n o f the t h e n a r muscles o r to an a b n o r m a l s u p p l y to these muscles f r o m the u l n a r nerve.
RESULTS F a i l u r e o f r e i n n e r v a t i o n o f the t h e n a r muscles was verified b y the clinical e x a m i n a t i o n which revealed t h e n a r e m i n e n c e a t r o p h y , as well as b y the E . M . G . which d e t e c t e d a d e l a y e d p a r t i a l r e i n n e r v a t i o n in the f o r m o f a high f r e q u e n c y tracing in one case, b u t this r e i n n e r v a t i o n was q u a n t i t a t i v e l y insufficient to explain the q u a l i t y o f the results.
1. paimar Abduction Results:
2. Pronation Results:
11 cases o f P a l m - P u l p d i s t a n c e 50 m m . 2 cases P a l m - P u l p d i s t a n c e 40 m m . 1 case P a l m - P u l p d i s t a n c e 30 m m .
8 cases: + + + (90 ~ _ 120 o) 4 cases: + + (50 ~ - - 90 ~ 2 cases: + (50 ~
194
The Hand-- Volume 11
No. 2.
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The Palm ar A bduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 7. This post-operative viewshows the maximum extension of the thumb. Fig. 8. This post-operative viewshows the pronation of the thumb. Fig. 9. This post-operative view shows the palmar abduction obtained in spite of thenar atrophy. 3. Pulp to Pulp Opposition:
True opposition was possible in all cases with the index finger and middle finger. True opposition was impossible with the ring finger in four cases. True opposition was impossible with the little finger in eight cases. DISCUSSION Paralysis of the thenar muscle results in loss of opposition of the t h u m b to the other fingers. The term " O p p o s i t i o n " needs clarifying as it is a complex action consisting of two movements: - - Palmar abduction. - - Axial Rotation (pronation) and slight adduction. The palmar abduction is at its greatest when the thumb is opposed to the index. It is less with opposition to the base of the little finger. The m a x i m u m adduction is obtained in opposition to the little finger. Axial rotation increases progressively in opposition from the index to the little finger. According to Kapandji, an automatic rotation occurs at the trapezio-metacarpal joint due to the combination of movements in two orthogonal planes, whereas a true rotation takes place in each of the three joints of the thumb, The palmar abduction and axial rotation are produced mainly by the abductor pollicis brevis and the opponens of the thumb as well as by the superficial fibres of the flexor potlicis brevis. The flexor pollicis brevis also produces a minor degree of adduction in the plane o f the palm. These muscles spread out in a large fan, whose sides f o r m an angle of about 90 ~ in a transverse plane. The most lateral fibres The Hand-- Volume l l
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The Palmar Abduction Pro.nation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
produce opposition to the index and middle fingers, whereas the medial fibres are more adductive and ensure opposition to the ring and little fingers. In an anter~posterior direction, the superficial palmar fibres are the most efficient, ensuring palmar abduction, but the bulk of the subjacent fibres helps to increase their lever action. Hence there is not just one type of opposition but several. It is impossible to reproduce all these movements by a single tendon transfer. According to Tubiana (1969) we can distinguish two types of transfer : those acting in the radial direction and those acting in the cubital direction. Tendon transfers whose action is medial and superficial have a minimal adduction component and rotation is subsequently incomplete. Their main action is palmar abduction but because of the wasting of the thenar eminence, the transfer is carried out in too deep a plane and antepulsion may be incomplete. (Fig la). To solve this problem Le Coeur combines with a bone graft fixed to the anterior aspect of the first metacarpal bone. (Fig. lb). This graft allows an increase of the angle of pull, thus increasing the efficiency of the transfer as regards palmar abduction. However, resorption of the bone graft is frequently observed several years afterwards and late results are not always satisfactory. The second type of transfer corresponds to those whose direction of traction is defined by the pisiform (Bunnell, 1924) and is therefore deep and medial. Their adduction action is better, but their palmar abduction action is often insufficient. Whichever type of transfer is used, the passive amplitude of palmar abduction and adduction may be limited by trapezio-metacarpal stiffness or contracture of the first web. In the literature concerning opposition transfers, the axial rotation is rarely measured with great precision, except in a recent paper by Jensen (1978). Numerous photos of mediocre rotation can be seen. The inadequate axial rotation may be due to insufficient palmar abduction a n d / o r adduction. We have observed, however, that tendon transfer alone never gives full amplitude of both those movements. Alternatively lack of pronation of the thumb may be due to stiffness of the joints, principally the trapezio-metacarpal, in an external rotation (supination) position. To improve pronation, many authors advise insertion of the distal extremity of the transferred tendon into the ulnar aspect of the thumb, after passing across the dorsal aspect o f the metacarpo-phalangeal joint. Adherence may, however, occure between the transfer and the extensors of the thumb, thus reducing the desired rotatory effect. The advantages of the palmar abduction-pronation osteotomy we have described are as follows: 1.
The lever action of the muscle is increased. (Fig. lc).
2. The thumb is m such a posit~on, that before movement is begun, there is already palmar abduction o f about 30 ~ to 40 ~ 3. When there ~s a contracture in an adduction supination position, osteotomy may render capsulotomy of the trapezio-metacarpal joint and liberation of the first web unnecessary. The inconvenience of osteotomy is that it limits the amplitude of extension, so that the thumb cannot come close to the plane of the other metacarpals. Complete 196
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The Palmar A bduction-Pronation Osteotomy of the First Metacarpal Bone Combined with Tendon Transfer for Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
opposition to the base of the little finger is frequently lost. However, the side pinch of the thumb with the index (key pinch) is not altered. Similarly too great pronation prevents opposition to the little finger. CONCLUSION The palmar abduction-pronation osteotomy associated with a tendon transfer allows restoration of good palmar abduction, good pronation and opposition to the index, middle and ring fingers. However, this osteotomy does not always solve the problem of adduction and opposition to the little finger. This operation is particularly indicated when a good result is not expected from a simple transfer, especially if there is stiffness of the trapezio-metacarpal joint in an adduction-extension-supination position with soft tissue contracture in the web space. REFERENCES BUNNELL, S. (1924) Reconstructive Surgery Of The Hand. Surgery Gynecology and Obstetrics, 39: 259-274. BOYES, J. H., Bunnell's Surgery of the Hand. Fourth edition. Philadelphia. J. B. Lippincott and Company (1964). DUCHENNE, (3. B. (1867) Physiology of Motion. Translated by E. B. Kaplan, Philadelphia, London. W. B. Saunders Company (1959). FOERSTER, O. (1930) Value of orthopaedic fixation operation on nerve disease; compensation for combined serratus trapesius paralysis by fixation of capsule to ribs with silverware; compensation for thenar paralysis by fixation of first metacarpal in flexed position by a bone implant. Acta Chirurgica Scandinavica, t930, 67: 351-376. JENSEN, E. (3. (1978) Restoration of Opposition of the Thumb. The Hand, 10: 161-167. KAPANDJI, A. (1972) La rotation du pouce sur son axe longitudinal lors de l'opposition, l~tude g~om~trique et m~canique de la trap~zo-m6tacarpienne (modUle m~canique de la main). Revue de Chirurgie Orthopedique et R6paratrice de l'Apparei| Moteur. 58, 4: 273-289. KAPLAN, E. B. (1965) Functional and Surgical Anatomy o( the Hand. Philadelphia. J. B. Lippincott Company. LE COEUR, M. P. (1953) Proced~ de restauration de l'opposition du pouce par transplantation sur chevalet. Revue de Chirurgie Orthopedique et Reparatrice de l'Appareil Moteur, 39: 655. TUBIANA, R. and ALNOT, J. Y. (1969) Paralysie de la Musculature Intrins~que du Pouce, Etude m~canique des transferts d'opposition du pouce. Semaine des Hopitaux de Paris. Annales de Chirurgie, 23: 889-898. ZANCOLLI, E. (1965) Tendon Transfers after lschemic Contractures of the Forearm. Classification in Relation to Intrinsic Muscle Disorders. The American Journal of Surgery, 109: 356-360.
The Hand-- Volume 11
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T H E P A L M A R A B D U C T I O N - P R O N A T I O N O S T E O T O M Y OF T H E FIRST M E T A C A R P A L B O N E C O M B I N E D W I T H T E N D O N T R A N S F E R FOR LATERAL THENAR MUSCLE PARALYSIS
J. J. C O M T E T and D. BEMELMANS, Lyon, France SUMMARY The authors describe a palmar abduction-pronationosteotomy of the first metacarpal bone combined with a tendon transfer for treatment of palsy of the lateral thenar muscles. The results of fourteen cases are reported. INTRODUCTION
The lateral thenar muscles (abductor pollicis brevis, opponens and flexor pollicis brevis) are responsible for the movements of palmar abduction and axial rotation (pronation) o f thumb column as well as some degree of adduction. Those muscles therefore play a fundamental role in opposing the thumb to the other fingers, (Duchenne, 1867; Kaplan, 1965; Kapandji, 1972). The palliative treatment of thenar muscle paralysis necessitates a tendon transfer. The different varieties of procedure are so numerous that it is difficult to report on them all, but their common principles were established by Bunnell (1924), Boyes (1964) Tubiana (1969). Other authors thought of acting on the thumb's skeleton either by fixation of the first metacarpal in opposition with a carpo-metacarpal arthrodesis (Foerster, 1930) or by an inlay bone graft on the anterior aspect of the first metacarpal bone to improve the lever action of the tendon transfer. (Le Coeur, 1953), (Fig lb). The aim of this work is to describe the technique and results of a method of palmar abduction-pronation osteotomy of the first metacarpal bone associated with a tendon transfer. CLINICAL MATERIAL Fifteen patients (eleven males, four females) were operated on by his new osteotomy technique. The average age was thirty-two years. The median nerve paralysis was due in thirteen cases to a wound with nerve injury. In one case it was due to a partial brachial plexus injury and in one case to congenital atrophy of the thenar muscles. Fourteen of the fifteen patients were followed up for two to five years with an average follow-up o f two and a half years. All the patients were subjected, before surgical intervention, to a thorough clinical examination of the hand, and electromyography, confirming the complete denervation of the thenar muscles, was always carried out. In addition to the paralysis, several of the patients had stiffness of the trapeziometacarpal joint in supination position of the thumb. SURGICAL TECHNIQUE All operations were carried out under general anaesthesia or brachialplexus block. A clear field was ensured by a pneumatic tourniquet. Pr Ag J. J. Comtet, Hfpital Edouard Herriot, Pavillon T, 69 374 Lyon Cedex 2, France. The Hand--Volume 11
No. 2.
1979
191
The Palmar A bduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 1. a. Lever action of a single transfer b. Lever action of a transfer with ale Coeur-type bone graft c. Lever action of a transfer with palmar abduction pronation osteotomy.
The skin incision extends from the trapezio-metacarpal joint to the proximal third of the second phalanx of the thumb. The slightly sinuous incision therefore passes along the outer border of the thenar eminence, allowing proper access to the first metacarpal bone and the extensor tendons. The periosteum of the first metacarpal is incised longitudinally, anterior to the extensor pollicis brevis, and elevated circumferentially, thus liberating the shaft from the muscular insertions. This is a very important step to allow rotation. Osteotomy is performed at the junction between the base and shaft in a zone of cancellous bone, allowing impaction and facilitating union. The osteotomy is first prepared by multiple holes of 2 mm in diameter and then completed by an osteotome. (Fig. 3). The distal part of the thumb is then placed in the axis of the middle finger in a palmar abduction and pronation, so that the distance between its pulp and the midcrease of the palm is fifty millimetres and its dorsal (nail) aspect is at a 135 ~ angle to the palm. The necessary angle of rotation varies from 60 ~ to 120 ~ according to each individual case. Fixation is provided by two Kirschner wires of 1.6 mm diameter : one is passed longitudinally through the distal metacarpal fragment, its point penetrating just far enough into the carpal bone, and the other one is introduced from the proximal to~ the distal fragment. (Fig. 4). Tendon transfer is then carried out according to Zancolli's modification of Tubiana's technique, using the tendon o f extensor pollicis brevis divided at its distal insertion, with the flexor carpi radialis as a pulley. It is reinserted into the tendon of the abductor pollicis brevis. (Fig. 2). In two cases the tendon of extensor pollicis brevis was so thin that we used instead the tendon o f the flexor digitorum superficialis of the ring finger. 192
The H a n d - - Volume 11
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The Palmar A b duction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
EZz3U: Fig. 2. Osteotomy of the first metacarpal bone with transfer of the extensor pollicis brevis. 1) Abductor pol|icis brevis 2) Extensor potlicis brevis 3) Flexor carpi radialis C l o s u r e is then c a r r i e d o u t in one l a y e r , a n d plaster cast i m m o b i l i s a t i o n lasts for three weeks. T h e K i r s c h n e r wires are w i t h d r a w n after a c o n t r o l X - r a y a r o u n d the sixth week. POSTOPERATIVE EVALUATION T h e criteria used in p o s t o p e r a t i v e e v a l u a t i o n were the following: 1. P a l m a r a b d u c t i o n , m e a s u r e d b y the vertical distance b e t w e e n the tip o f t h e t h u m b a n d the m i d c r e a s e o f the p a l m . 2. R o t a t i o n ( p r o n a t i o n ) is difficult to e v a l u a t e even using t h e " m a t c h e s m e t h o d " o f
,\
C3 Fig. 3. a,b,c, Surgical technique of the palmar-abduction pronation osteotomy. The Hand--Volume 11
No. 2.
1979
193
The Palmar Abduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 4. Fixation is ensured by two Kirschner wires. Note the impacted fragments. Fig. 5. Preoperative view showing atrophy of the thenar muscles and absences of abduction and pronation of the thumb. Fig. 6. This post-operative of the same hand shows for comparison the palmar abduction and pronation of the thumb. Bunnell. W e assess it by l o o k i n g at the h a n d f r o m its distal end in the axis o f the fingers. W e o b s e r v e the progressive h o r i z o n t a l p o s i t i o n o f the t h u m b nail, when the latter is o p p o s e d f r o m the index to the little finger. R o t a t i o n is m e a s u r e d in o p p o s i t i o n to the m i d d l e finger, being the angle f o r m e d between the nail p l a n e a n d the p a l m a r p l a n e . This is a difficult m e a s u r e m e n t , b e c a u s e the m a r g i n o f e r r o r can be as high as 20 ~ , so we express it as follows: + 5 0 ~ + + 5 0 ~ to 90 ~ + + + 9 0 ~ to 120 ~ 3. T i p t o T i p o p p o s i t i o n where the p u l p o f the t h u m b t o u c h e s the p u l p o f the o t h e r fingers. This s h o u l d be d i s t i n g u i s h e d f r o m o p p o s i t i o n to o t h e r p a l m a r parts o f the fingers especially to the base o f the little finger. 4. E . M . G . E l e c t r o m y o g r a p h y later helps to p r o v e t h a t the f u n c t i o n a l i m p r o v e m e n t is n o t d u e to a d e l a y e d r e i n n e r v a t i o n o f the t h e n a r muscles o r to an a b n o r m a l s u p p l y to these muscles f r o m the u l n a r nerve.
RESULTS F a i l u r e o f r e i n n e r v a t i o n o f the t h e n a r muscles was verified b y the clinical e x a m i n a t i o n which revealed t h e n a r e m i n e n c e a t r o p h y , as well as b y the E . M . G . which d e t e c t e d a d e l a y e d p a r t i a l r e i n n e r v a t i o n in the f o r m o f a high f r e q u e n c y tracing in one case, b u t this r e i n n e r v a t i o n was q u a n t i t a t i v e l y insufficient to explain the q u a l i t y o f the results.
1. paimar Abduction Results:
2. Pronation Results:
11 cases o f P a l m - P u l p d i s t a n c e 50 m m . 2 cases P a l m - P u l p d i s t a n c e 40 m m . 1 case P a l m - P u l p d i s t a n c e 30 m m .
8 cases: + + + (90 ~ _ 120 o) 4 cases: + + (50 ~ - - 90 ~ 2 cases: + (50 ~
194
The Hand-- Volume 11
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1979
The Palm ar A bduction-Pronation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
Fig. 7. This post-operative viewshows the maximum extension of the thumb. Fig. 8. This post-operative viewshows the pronation of the thumb. Fig. 9. This post-operative view shows the palmar abduction obtained in spite of thenar atrophy. 3. Pulp to Pulp Opposition:
True opposition was possible in all cases with the index finger and middle finger. True opposition was impossible with the ring finger in four cases. True opposition was impossible with the little finger in eight cases. DISCUSSION Paralysis of the thenar muscle results in loss of opposition of the t h u m b to the other fingers. The term " O p p o s i t i o n " needs clarifying as it is a complex action consisting of two movements: - - Palmar abduction. - - Axial Rotation (pronation) and slight adduction. The palmar abduction is at its greatest when the thumb is opposed to the index. It is less with opposition to the base of the little finger. The m a x i m u m adduction is obtained in opposition to the little finger. Axial rotation increases progressively in opposition from the index to the little finger. According to Kapandji, an automatic rotation occurs at the trapezio-metacarpal joint due to the combination of movements in two orthogonal planes, whereas a true rotation takes place in each of the three joints of the thumb, The palmar abduction and axial rotation are produced mainly by the abductor pollicis brevis and the opponens of the thumb as well as by the superficial fibres of the flexor potlicis brevis. The flexor pollicis brevis also produces a minor degree of adduction in the plane o f the palm. These muscles spread out in a large fan, whose sides f o r m an angle of about 90 ~ in a transverse plane. The most lateral fibres The Hand-- Volume l l
No. 2.
1979
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The Palmar Abduction Pro.nation Osteotomy o f the First Metacarpal Bone Combined with Tendon Transfer f o r Lateral Thenar Muscle Paralysis J. J. Comtet and D. Bemelmans
produce opposition to the index and middle fingers, whereas the medial fibres are more adductive and ensure opposition to the ring and little fingers. In an anter~posterior direction, the superficial palmar fibres are the most efficient, ensuring palmar abduction, but the bulk of the subjacent fibres helps to increase their lever action. Hence there is not just one type of opposition but several. It is impossible to reproduce all these movements by a single tendon transfer. According to Tubiana (1969) we can distinguish two types of transfer : those acting in the radial direction and those acting in the cubital direction. Tendon transfers whose action is medial and superficial have a minimal adduction component and rotation is subsequently incomplete. Their main action is palmar abduction but because of the wasting of the thenar eminence, the transfer is carried out in too deep a plane and antepulsion may be incomplete. (Fig la). To solve this problem Le Coeur combines with a bone graft fixed to the anterior aspect of the first metacarpal bone. (Fig. lb). This graft allows an increase of the angle of pull, thus increasing the efficiency of the transfer as regards palmar abduction. However, resorption of the bone graft is frequently observed several years afterwards and late results are not always satisfactory. The second type of transfer corresponds to those whose direction of traction is defined by the pisiform (Bunnell, 1924) and is therefore deep and medial. Their adduction action is better, but their palmar abduction action is often insufficient. Whichever type of transfer is used, the passive amplitude of palmar abduction and adduction may be limited by trapezio-metacarpal stiffness or contracture of the first web. In the literature concerning opposition transfers, the axial rotation is rarely measured with great precision, except in a recent paper by Jensen (1978). Numerous photos of mediocre rotation can be seen. The inadequate axial rotation may be due to insufficient palmar abduction a n d / o r adduction. We have observed, however, that tendon transfer alone never gives full amplitude of both those movements. Alternatively lack of pronation of the thumb may be due to stiffness of the joints, principally the trapezio-metacarpal, in an external rotation (supination) position. To improve pronation, many authors advise insertion of the distal extremity of the transferred tendon into the ulnar aspect of the thumb, after passing across the dorsal aspect o f the metacarpo-phalangeal joint. Adherence may, however, occure between the transfer and the extensors of the thumb, thus reducing the desired rotatory effect. The advantages of the palmar abduction-pronation osteotomy we have described are as follows: 1.
The lever action of the muscle is increased. (Fig. lc).
2. The thumb is m such a posit~on, that before movement is begun, there is already palmar abduction o f about 30 ~ to 40 ~ 3. When there ~s a contracture in an adduction supination position, osteotomy may render capsulotomy of the trapezio-metacarpal joint and liberation of the first web unnecessary. The inconvenience of osteotomy is that it limits the amplitude of extension, so that the thumb cannot come close to the plane of the other metacarpals. Complete 196
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opposition to the base of the little finger is frequently lost. However, the side pinch of the thumb with the index (key pinch) is not altered. Similarly too great pronation prevents opposition to the little finger. CONCLUSION The palmar abduction-pronation osteotomy associated with a tendon transfer allows restoration of good palmar abduction, good pronation and opposition to the index, middle and ring fingers. However, this osteotomy does not always solve the problem of adduction and opposition to the little finger. This operation is particularly indicated when a good result is not expected from a simple transfer, especially if there is stiffness of the trapezio-metacarpal joint in an adduction-extension-supination position with soft tissue contracture in the web space. REFERENCES BUNNELL, S. (1924) Reconstructive Surgery Of The Hand. Surgery Gynecology and Obstetrics, 39: 259-274. BOYES, J. H., Bunnell's Surgery of the Hand. Fourth edition. Philadelphia. J. B. Lippincott and Company (1964). DUCHENNE, (3. B. (1867) Physiology of Motion. Translated by E. B. Kaplan, Philadelphia, London. W. B. Saunders Company (1959). FOERSTER, O. (1930) Value of orthopaedic fixation operation on nerve disease; compensation for combined serratus trapesius paralysis by fixation of capsule to ribs with silverware; compensation for thenar paralysis by fixation of first metacarpal in flexed position by a bone implant. Acta Chirurgica Scandinavica, t930, 67: 351-376. JENSEN, E. (3. (1978) Restoration of Opposition of the Thumb. The Hand, 10: 161-167. KAPANDJI, A. (1972) La rotation du pouce sur son axe longitudinal lors de l'opposition, l~tude g~om~trique et m~canique de la trap~zo-m6tacarpienne (modUle m~canique de la main). Revue de Chirurgie Orthopedique et R6paratrice de l'Apparei| Moteur. 58, 4: 273-289. KAPLAN, E. B. (1965) Functional and Surgical Anatomy o( the Hand. Philadelphia. J. B. Lippincott Company. LE COEUR, M. P. (1953) Proced~ de restauration de l'opposition du pouce par transplantation sur chevalet. Revue de Chirurgie Orthopedique et Reparatrice de l'Appareil Moteur, 39: 655. TUBIANA, R. and ALNOT, J. Y. (1969) Paralysie de la Musculature Intrins~que du Pouce, Etude m~canique des transferts d'opposition du pouce. Semaine des Hopitaux de Paris. Annales de Chirurgie, 23: 889-898. ZANCOLLI, E. (1965) Tendon Transfers after lschemic Contractures of the Forearm. Classification in Relation to Intrinsic Muscle Disorders. The American Journal of Surgery, 109: 356-360.
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