- Email: [email protected]
Sesamoid arthrodesis for hyperextension of the thumb metacarpophalangeal joint
Sesamoid Arthrodesis for Hyperextension of the Thumb Metacarpophalangeal Joint Michael A. Tonkin, FRCS, Anthony J. Beard, MB, Stephen J. Kemp, FRACS, Sydney, Australia, and Darrin F. Eakins, MD, Portland, OR Forty-two sesamoid arthrodeses performed since 1986 were reviewed, Thirty-seven cases were considered successful. Hypertension recurred in 3 of the 20 procedures performed for cerebral palsy and 1 of the 21 performed in association with basal joint arthroplasty for arthritic conditions. The single post trauma case was successful. Flexion was preserved. Prevention of hyperextension of the metacarpophalangeal joint assists in reducing metacarpal adduction in cerebral palsy and has a stabilizing effect in basal joint arthroplasty. (J Hand Surg 1995;20A: 334-338.)
H y p e r e x t e n s i o n of the thumb m e t a c a r p o p h a langeal (MP)joint is a variant of mobility. Pathologic MP joint hyperextension is associated with rupture or attenuation of the palmar plate in association with injury, degenerative and inflammatory arthritis, and spastic, paralytic, and congenital disorders. A number of surgical procedures have been described to overcome thumb MP joint hyperextension. This paper details the results obtained using the sesamoid arthrodesis technique of Zancolli.
Materials and Methods Between June 1986 and March 1993, 45 sesamoid arthrodeses were performed. Three were lost to followup examination, allowing 37 patients with 42 operations for review. These patients were divided into two main groups with Group 1 patients suffering from cerebral palsy and Group 2 patients in whom sesamoid arthrodesis was performed in association with arthroplasty of the carpometacarpal (CMC) joint. From Department of Hand Surgery, Royal North Shore Hospital, Sydney, Australia, and Department of Orthopaedics, Oregon Health Sciences University, Portland, OR. Received for publication June 20, 1994; accepted in revised form Sept. 6, 1994. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Michael A. Tonkin, Department of Hand Surgery, Royal North Shore Hospital, Sydney, Australia.
334
The Journal of Hand Surgery
Twenty sesamoid arthrodeses were performed in 17 patients with cerebral palsy. Twelve were boys/ men and 5 girls/women. Their ages ranged from 5 to 25 years, average 12 years. Time to followup examination ranged from 6 to 88 months with an average of 32 months. T w e n t y - o n e s e s a m o i d a r t h r o d e s e s were performed in association with arthroplasty of the CMC joint in 19 patients, 18 women and 1 man. Eighteen procedures were for osteoarthritis and three for rheumatoid arthritis. Their ages ranged from 40 to 74 years with an average of 62 years. Time to followup examination ranged from 6 to 59 months with an average of 24 months. Metacarpophalangeal joint sesamoid arthrodesis was also performed in one 16-year-old girl, following a traumatic degloving hand injury with subsequent first web contraction and MP joint hyperextension. Assessment involved clinical measurement of motion at the MP joint, palpation for MP joint tenderness, and the presence of subjective pain. Initially x-ray film examination was performed. However, it was difficult to assess x-ray film union at the arthrodesis site, so this was discontinued. Surgical Technique The operation performed was a modification of the technique described by Zancolli. 1 The MP joint of the thumb was approached through either a dorsal c o n t i n u a t i o n of the incision for the CMC j o i n t
The Journal of Hand Surgery / Vol. 20A No. 2 March 1995
335
COLLATERAL LIGAMENT EXTENSOR
30%
CORTICAL DEFECT
SESAMOID SEAM REPAIRED
Figure 1. The palmar plate is mobilized by dividing the accessory collateral ligament at its insertion into the palmar plate. The articular surface of the sesamoid is denuded of cartilage. A cortical defect is made at the headneck junction of the metacarpal. a r t h r o p l a s t y or t h r o u g h a c u r v e d d o r s o r a d i a l incision. The palmar plate was mobilized along with the radial sesamoid by dividing the accessory collateral ligament at its insertion into the edge of the p a l m a r plate and a d v a n c i n g the p a l m a r plate p r o x i m a l l y . The articular surface of the sesamoid was denuded of cartilage using a B e a v e r blade. A defect was created at the h e a d - n e c k j u n c t i o n o f the m e t a c a r p a l (Fig. I). The sesamoid was held in the defect created by passing a suture f r o m the p a l m a r aspect through two holes in the s e s a m o i d - p a l m a r plate c o m p l e x and the metacarpal neck. To provide m o r e precise control of entry point, two free straight needles were loaded separately into a K i r s c h n e r wire driver and used to p a s s t h e 3/0 P r o l e n e s u t u r e t h r o u g h t h e s e s a m o i d - p a l m a r p l a t e c o m p l e x and m e t a c a r p a l ; 4/0 Prolene suture was used in children. In the early cases, this suture exited dorsally through skin and was tied o v e r a dental role as a pull-out suture. In the later cases, the interosseous suture was tied o v e r the m e t a c a r p a l under the e x t e n s o r tendons as a permanent suture (Fig. 2). Prior to securing the sesam o l d - m e t a c a r p a l suture, a fine Kirschner wire was
Figure 3. The intraosseous suture is tied over the metacarpal under the extensor tendons as a permanent suture. A Kirschner wire is placed across the MPJ to maintain the joint in approximately 30~ flexion. The seam in the collateral ligament is repaired and the proximal radial edge of the palmar plate is sutured to the metacarpal periosteum and aponeurotic fibers of the abductor pollicis brevis.
inserted across the M P j o i n t to maintain the M P j o i n t at 30 ~ flexion. The sesamoid was further secured by suturing the proximal radial edge of the p a l m a r plate to m e t a c a r p a l periosteum and to aponeurotic fibers of the insertion of a b d u c t o r pollicis brevis (Fig. 3). A plaster spica protects the M P j o i n t and allows motion of the interphalangeal joint. The K i r s h n e r wire and plaster are r e m o v e d at 5 w e e k s w h e n active flexion is allowed.
Results Group 1
This group includes 20 sesamoid arthrodeses perf o r m e d on patients with cerebral palsy. The average p r e o p e r a t i v e h y p e r e x t e n s i o n was 38 ~ Average maximal p o s t o p e r a t i v e extension was 3 ~ flexion (Table 1) (Figs. 4 and 5). This includes 10 thumbs that extended to neutral and 6 with maximal extension be-
Table 1. G r o u p 1, Cerebral Palsy (n = 20) Preoperative
Figure 2. Two straight needles loaded into a Kirschner wire driver are used to pass a Prolene suture through the sesamoid-palmar plate complex and metacarpal neck to secure the sesamoid into the cortical defect created.
Maximal extension of MP joint (degrees of flexion) Mean* Range Maximal flexion of MP joint (degrees of flexion) Mean Range Mean loss of flexion
Postoperative
-38**
3
-20to -50
- 5 to 15
55 40 to 70
47 30 to 70 8
* Means do not include three failures. ** Negative numbers denote hyperextension.
336
Tonkin et al. / Sesamoid Arthrodesis of the Thumb Table 2. G r o u p 2, CMC Joint Arthroplasty G r o u p (n = 21)
Preoperative Maximal extension of MP joint (degrees of flexion) Mean* Range Maximal flexion of MP joint (degrees of flexion) Mean Range Mean loss of flexion Figure 4. Hyperextension of right thumb MCPJ before sesamoid arthrodesis,
tween 3~ and 20 ~ flexion at the MPjoint. One patient had 5~ postoperative hyperextension but was functionally stable. There were three recurrences to the preoperative position. Two at 30 ~ hyperextension were successfully revised. A third patient had a recurrence of 50 ~ hyperextension. N o further surgery has been performed to date. In two further patients the sesamoid arthrodesis was revised to a MP joint arthrodesis for persistent thumb in palm position. This was not a failure of sesamoid arthrodesis, but was due to the lack of effective extensor-abductor motors. The average preoperative flexion was 55 ~ and fell to 47 ~ following surgery, giving an average loss of flexion of 8~. In many of the children, there was minimal ossification of the sesamoid. Successful cases are due to a chondrodesis or firm fibrous union.
- 23** - 45 to - 10
43 20 to 80
Postoperative
-
4 10 to 25 35 5 to 70 8
* Means do not include one failure. ** Negative numbers denote hyperextension.
Group 2 This group includes 21 sesamoid arthrodeses performed in conjunction with arthroplasty of an arthritic C M C joint. The average preoperative hyperextension was 23 ~. Average maximal postoperative extension was 4 ~ of flexion at the MP joint (Table 2). Extension was blocked at neutral position in nine cases and was limited to between 5~ and 25 ~ flexion in eight cases. One patient had a bilateral recurrence of 10~ hyperextension and one had a recurrence of 5~ All were functionally stable. One recurrence of 20 ~ was considered a failure. The average preoperative flexion of 43 ~ decreased to an average of 35 ~ following surgery. This gives an average flexion loss of 8 ~ in this group as well. T w o patients complained of pain and tenderness dorsally, which disappeared following late removal of a prominent pull-out suture. Tenderness was not detected at the arthrodesis site.
Traumatic Case A successful sesamoid arthrodesis was performed in a single trauma case combined with an intrinsic release of the thumb and deepening of the first web space. The preoperative range of motion was from 30 ~ h y p e r e x t e n s i o n to 45 ~ flexion. R e v i e w at 12 months revealed a stable joint with a range of motion from 5 ~ flexion to 45 ~ flexion.
Discussion
Figure 5. The same thumb following sesamoid arthrodesis. Maximal extension is limited to approximately 5~ flexion.
We believe that correction of MP joint hyperextension is important in the successful reconstruction of those thumbs with metacarpal adduction deformities a c c o m p a n y i n g M P j o i n t h y p e r e x t e n s i o n . In those patients with cerebral palsy, attempts to draw
The Journal of Hand Surgery / Vol. 20A No. 2 March 1995
the adducted metacarpal out of the palm through tendon transfers to extensor pollicis longus or extensor pollicis brevis are compromised by resultant MP joint hyperextension. The metacarpal continues to adduct in spite of adductor release. Surgery for the arthritic basal joint of the thumb is less likely to be successful when metacarpal adduction and CMC joint subluxation is accompanied by MP joint hyperextension (Z collapse). Activities that force the MP joint into the hyperextended position simultaneously cause the metacarpal to adduct, increasing the dorsoradial subluxing force at the CMC j o i n t and c o m p r o m i s i n g w h a t e v e r reconstructive procedure is performed at this level. Zancolli2 (1957) described a capsuloplasty for correcting MP joint hyperextension of the fingers in claw hand caused by paralysis of the intrinsic muscles. He modified this for MP joint hyperextension of the thumb in 1979,1 incorporating a synotosis between the radial sesamoid and the neck of the first metacarpal. Filler, Stark, and Boyes 3 described a palmar capsulodesis in children with cerebral palsy. In 13 cases the postoperative positions ranged between 20~ and 30~. The initial correction was lost in two cases but hyperextension did not recur. Eaton and F l o y d 4 reviewed 13 palmar capsulodeses performed in association with basal joint arthroplasty. In three cases h y p e r e x t e n s i o n recurred. Two were considered good results with only 10~hyperextension, and the third fair with 20 ~hyperextension. In three cases half the preoperative flexion was lost. Schuurman and Bos 5 found satisfactory results in eight patients in whom palmar capsulodesis was performed for hyperextension deformity of the MPjoint of the thumb, five following trauma and three with cerebral palsy. Kessler 6 believed palmar capsulodesis would stretch and suggested strengthening the palmar plate by a crisscross palmar transposition of a strip of extensor pollicis brevis tendon. The arc of movement retained was only 10~ ~ and 2 of 11 patients had recurrence of 20~ hyperextension. Eiken 7 also advised against palmar capsulodesis, describing a palmaris longus tenodesis. He claimed improved function in all seven patients but gave no measurements. The results from this study indicate that sesamoid arthrodesis is successful in correcting hyperextension of the MP joint of the thumb. Satisfactory results were demonstrated in patients with cerebral palsy and in those in whom the surgery was performed in association with CMC joint arthroplasty in patients with both degenerative and inflammatory
337
arthritides. Success was also achieved in the single traumatic case. Of the 42 procedures, 38 were considered successful and 4 unsuccessful. However, one patient with cerebral palsy and one Group 2 patient had recurrent deformity of 5~hyperextension and one patient with degenerative arthritis had a recurrence of 10~ hyperextension in both thumbs. All were functionally stable and were considered successful procedures according to the criteria of Eaton and Floyd. 4 These results compare favorably with those of capsulodesis and palmar plate reinforcing procedures outlined earlier. The concerns of Kessler and Eiken that the palmar plate would stretch have not been substantiated in this study. Failures, when they occurred, were noted within the first 6 months. Two of these (Group 1 patients) were successfully revised. The failure was seen to be at the sesamoid metacarpal junction, where fusion or stable fibrous union had not occurred, rather than within the palmar plate. Adequate sesamoid bone remained for revision. All four failures occurred with the early technique, in which a pull-out suture was used. The use of a permanent suture is now advocated. However, prominent sutures needed removal in two cases due to tenderness. Other possible improvements in technique could be considered. It may be more appropriate to secure the sesamoid prior to insertion of the protective Kirschner wire across the MPjoint. This allows a better assessment of the tension within the reconstruction and more proximal placement of the sesamoid with greater MP joint flexion, if appropriate. MPjoint arthrodesis is an effective means of preventing h y p e r e x t e n s i o n when there are arthritic changes present within the joint. This is a most satisfactory procedure but does have the disadvantages of removing flexion at the MP joint and creating a longer lever arm based at the CMC joint. Therefore we believe that sesamoid arthrodesis is a superior procedure when the MPjoint is otherwise stable (in all planes other than in the hyperextension plane) and when more than 30~preoperative flexion is present. This study indicates that the preoperative range of flexion is largely maintained postoperatively. However, if less than 30 ~ preoperative flexion is present, then the small range of motion obtained after sesamoid arthrodesis is probably not functional and MP joint arthrodesis is indicated.
References 1. Zancolli EA. Structural and dynamic bases of hand surgery, 2nd ed. Philadelphia: JB Lippincott, 1979:212. 2. Zancolli EA. Claw hand caused by paralysis of the
:]38
Tonkin et al. / Sesamoid Arthrodesis of the Thumb
intrinsic muscles. A simple procedure for its correction. J Bone Joint Surg 1957;39A:1076-80. 3. Filler BC, Stark HH, Boyes JH. Capsulodesis of the metacarpophalangeal joint of the thumb in children with cerebral palsy. J Bone Joint Surg 1976;58A: 667-70. 4. Eaton RG, Floyd WE. Thumb metacarpophalangeal capsulodesis: an adjunct procedure to basal joint arthroplasty for collapse deformity of the first ray. J Hand Surg 1988;13A:461-5.
5. Schuurman AH, Bos KE. Treatment of volar instability of the metacarpophalangeal joint of the thumb by volar capsulodesis. J Bone Joint Surg 1993;18B: 346-9. 6. Kessler I. A simplified technique to correct hyperextension deformity of the metacarpophalangeal joint of the thumb. J Bone Joint Surg 1979;61A:903-5. 7. Eiken O. Palmaris longus tenodesis for hyperextension of the thumb metacarpophalangeal joint. Scand J Plast Reconstr Surg 1981 ;15:149-52.
H y p e r e x t e n s i o n of the thumb m e t a c a r p o p h a langeal (MP)joint is a variant of mobility. Pathologic MP joint hyperextension is associated with rupture or attenuation of the palmar plate in association with injury, degenerative and inflammatory arthritis, and spastic, paralytic, and congenital disorders. A number of surgical procedures have been described to overcome thumb MP joint hyperextension. This paper details the results obtained using the sesamoid arthrodesis technique of Zancolli.
Materials and Methods Between June 1986 and March 1993, 45 sesamoid arthrodeses were performed. Three were lost to followup examination, allowing 37 patients with 42 operations for review. These patients were divided into two main groups with Group 1 patients suffering from cerebral palsy and Group 2 patients in whom sesamoid arthrodesis was performed in association with arthroplasty of the carpometacarpal (CMC) joint. From Department of Hand Surgery, Royal North Shore Hospital, Sydney, Australia, and Department of Orthopaedics, Oregon Health Sciences University, Portland, OR. Received for publication June 20, 1994; accepted in revised form Sept. 6, 1994. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Michael A. Tonkin, Department of Hand Surgery, Royal North Shore Hospital, Sydney, Australia.
334
The Journal of Hand Surgery
Twenty sesamoid arthrodeses were performed in 17 patients with cerebral palsy. Twelve were boys/ men and 5 girls/women. Their ages ranged from 5 to 25 years, average 12 years. Time to followup examination ranged from 6 to 88 months with an average of 32 months. T w e n t y - o n e s e s a m o i d a r t h r o d e s e s were performed in association with arthroplasty of the CMC joint in 19 patients, 18 women and 1 man. Eighteen procedures were for osteoarthritis and three for rheumatoid arthritis. Their ages ranged from 40 to 74 years with an average of 62 years. Time to followup examination ranged from 6 to 59 months with an average of 24 months. Metacarpophalangeal joint sesamoid arthrodesis was also performed in one 16-year-old girl, following a traumatic degloving hand injury with subsequent first web contraction and MP joint hyperextension. Assessment involved clinical measurement of motion at the MP joint, palpation for MP joint tenderness, and the presence of subjective pain. Initially x-ray film examination was performed. However, it was difficult to assess x-ray film union at the arthrodesis site, so this was discontinued. Surgical Technique The operation performed was a modification of the technique described by Zancolli. 1 The MP joint of the thumb was approached through either a dorsal c o n t i n u a t i o n of the incision for the CMC j o i n t
The Journal of Hand Surgery / Vol. 20A No. 2 March 1995
335
COLLATERAL LIGAMENT EXTENSOR
30%
CORTICAL DEFECT
SESAMOID SEAM REPAIRED
Figure 1. The palmar plate is mobilized by dividing the accessory collateral ligament at its insertion into the palmar plate. The articular surface of the sesamoid is denuded of cartilage. A cortical defect is made at the headneck junction of the metacarpal. a r t h r o p l a s t y or t h r o u g h a c u r v e d d o r s o r a d i a l incision. The palmar plate was mobilized along with the radial sesamoid by dividing the accessory collateral ligament at its insertion into the edge of the p a l m a r plate and a d v a n c i n g the p a l m a r plate p r o x i m a l l y . The articular surface of the sesamoid was denuded of cartilage using a B e a v e r blade. A defect was created at the h e a d - n e c k j u n c t i o n o f the m e t a c a r p a l (Fig. I). The sesamoid was held in the defect created by passing a suture f r o m the p a l m a r aspect through two holes in the s e s a m o i d - p a l m a r plate c o m p l e x and the metacarpal neck. To provide m o r e precise control of entry point, two free straight needles were loaded separately into a K i r s c h n e r wire driver and used to p a s s t h e 3/0 P r o l e n e s u t u r e t h r o u g h t h e s e s a m o i d - p a l m a r p l a t e c o m p l e x and m e t a c a r p a l ; 4/0 Prolene suture was used in children. In the early cases, this suture exited dorsally through skin and was tied o v e r a dental role as a pull-out suture. In the later cases, the interosseous suture was tied o v e r the m e t a c a r p a l under the e x t e n s o r tendons as a permanent suture (Fig. 2). Prior to securing the sesam o l d - m e t a c a r p a l suture, a fine Kirschner wire was
Figure 3. The intraosseous suture is tied over the metacarpal under the extensor tendons as a permanent suture. A Kirschner wire is placed across the MPJ to maintain the joint in approximately 30~ flexion. The seam in the collateral ligament is repaired and the proximal radial edge of the palmar plate is sutured to the metacarpal periosteum and aponeurotic fibers of the abductor pollicis brevis.
inserted across the M P j o i n t to maintain the M P j o i n t at 30 ~ flexion. The sesamoid was further secured by suturing the proximal radial edge of the p a l m a r plate to m e t a c a r p a l periosteum and to aponeurotic fibers of the insertion of a b d u c t o r pollicis brevis (Fig. 3). A plaster spica protects the M P j o i n t and allows motion of the interphalangeal joint. The K i r s h n e r wire and plaster are r e m o v e d at 5 w e e k s w h e n active flexion is allowed.
Results Group 1
This group includes 20 sesamoid arthrodeses perf o r m e d on patients with cerebral palsy. The average p r e o p e r a t i v e h y p e r e x t e n s i o n was 38 ~ Average maximal p o s t o p e r a t i v e extension was 3 ~ flexion (Table 1) (Figs. 4 and 5). This includes 10 thumbs that extended to neutral and 6 with maximal extension be-
Table 1. G r o u p 1, Cerebral Palsy (n = 20) Preoperative
Figure 2. Two straight needles loaded into a Kirschner wire driver are used to pass a Prolene suture through the sesamoid-palmar plate complex and metacarpal neck to secure the sesamoid into the cortical defect created.
Maximal extension of MP joint (degrees of flexion) Mean* Range Maximal flexion of MP joint (degrees of flexion) Mean Range Mean loss of flexion
Postoperative
-38**
3
-20to -50
- 5 to 15
55 40 to 70
47 30 to 70 8
* Means do not include three failures. ** Negative numbers denote hyperextension.
336
Tonkin et al. / Sesamoid Arthrodesis of the Thumb Table 2. G r o u p 2, CMC Joint Arthroplasty G r o u p (n = 21)
Preoperative Maximal extension of MP joint (degrees of flexion) Mean* Range Maximal flexion of MP joint (degrees of flexion) Mean Range Mean loss of flexion Figure 4. Hyperextension of right thumb MCPJ before sesamoid arthrodesis,
tween 3~ and 20 ~ flexion at the MPjoint. One patient had 5~ postoperative hyperextension but was functionally stable. There were three recurrences to the preoperative position. Two at 30 ~ hyperextension were successfully revised. A third patient had a recurrence of 50 ~ hyperextension. N o further surgery has been performed to date. In two further patients the sesamoid arthrodesis was revised to a MP joint arthrodesis for persistent thumb in palm position. This was not a failure of sesamoid arthrodesis, but was due to the lack of effective extensor-abductor motors. The average preoperative flexion was 55 ~ and fell to 47 ~ following surgery, giving an average loss of flexion of 8~. In many of the children, there was minimal ossification of the sesamoid. Successful cases are due to a chondrodesis or firm fibrous union.
- 23** - 45 to - 10
43 20 to 80
Postoperative
-
4 10 to 25 35 5 to 70 8
* Means do not include one failure. ** Negative numbers denote hyperextension.
Group 2 This group includes 21 sesamoid arthrodeses performed in conjunction with arthroplasty of an arthritic C M C joint. The average preoperative hyperextension was 23 ~. Average maximal postoperative extension was 4 ~ of flexion at the MP joint (Table 2). Extension was blocked at neutral position in nine cases and was limited to between 5~ and 25 ~ flexion in eight cases. One patient had a bilateral recurrence of 10~ hyperextension and one had a recurrence of 5~ All were functionally stable. One recurrence of 20 ~ was considered a failure. The average preoperative flexion of 43 ~ decreased to an average of 35 ~ following surgery. This gives an average flexion loss of 8 ~ in this group as well. T w o patients complained of pain and tenderness dorsally, which disappeared following late removal of a prominent pull-out suture. Tenderness was not detected at the arthrodesis site.
Traumatic Case A successful sesamoid arthrodesis was performed in a single trauma case combined with an intrinsic release of the thumb and deepening of the first web space. The preoperative range of motion was from 30 ~ h y p e r e x t e n s i o n to 45 ~ flexion. R e v i e w at 12 months revealed a stable joint with a range of motion from 5 ~ flexion to 45 ~ flexion.
Discussion
Figure 5. The same thumb following sesamoid arthrodesis. Maximal extension is limited to approximately 5~ flexion.
We believe that correction of MP joint hyperextension is important in the successful reconstruction of those thumbs with metacarpal adduction deformities a c c o m p a n y i n g M P j o i n t h y p e r e x t e n s i o n . In those patients with cerebral palsy, attempts to draw
The Journal of Hand Surgery / Vol. 20A No. 2 March 1995
the adducted metacarpal out of the palm through tendon transfers to extensor pollicis longus or extensor pollicis brevis are compromised by resultant MP joint hyperextension. The metacarpal continues to adduct in spite of adductor release. Surgery for the arthritic basal joint of the thumb is less likely to be successful when metacarpal adduction and CMC joint subluxation is accompanied by MP joint hyperextension (Z collapse). Activities that force the MP joint into the hyperextended position simultaneously cause the metacarpal to adduct, increasing the dorsoradial subluxing force at the CMC j o i n t and c o m p r o m i s i n g w h a t e v e r reconstructive procedure is performed at this level. Zancolli2 (1957) described a capsuloplasty for correcting MP joint hyperextension of the fingers in claw hand caused by paralysis of the intrinsic muscles. He modified this for MP joint hyperextension of the thumb in 1979,1 incorporating a synotosis between the radial sesamoid and the neck of the first metacarpal. Filler, Stark, and Boyes 3 described a palmar capsulodesis in children with cerebral palsy. In 13 cases the postoperative positions ranged between 20~ and 30~. The initial correction was lost in two cases but hyperextension did not recur. Eaton and F l o y d 4 reviewed 13 palmar capsulodeses performed in association with basal joint arthroplasty. In three cases h y p e r e x t e n s i o n recurred. Two were considered good results with only 10~hyperextension, and the third fair with 20 ~hyperextension. In three cases half the preoperative flexion was lost. Schuurman and Bos 5 found satisfactory results in eight patients in whom palmar capsulodesis was performed for hyperextension deformity of the MPjoint of the thumb, five following trauma and three with cerebral palsy. Kessler 6 believed palmar capsulodesis would stretch and suggested strengthening the palmar plate by a crisscross palmar transposition of a strip of extensor pollicis brevis tendon. The arc of movement retained was only 10~ ~ and 2 of 11 patients had recurrence of 20~ hyperextension. Eiken 7 also advised against palmar capsulodesis, describing a palmaris longus tenodesis. He claimed improved function in all seven patients but gave no measurements. The results from this study indicate that sesamoid arthrodesis is successful in correcting hyperextension of the MP joint of the thumb. Satisfactory results were demonstrated in patients with cerebral palsy and in those in whom the surgery was performed in association with CMC joint arthroplasty in patients with both degenerative and inflammatory
337
arthritides. Success was also achieved in the single traumatic case. Of the 42 procedures, 38 were considered successful and 4 unsuccessful. However, one patient with cerebral palsy and one Group 2 patient had recurrent deformity of 5~hyperextension and one patient with degenerative arthritis had a recurrence of 10~ hyperextension in both thumbs. All were functionally stable and were considered successful procedures according to the criteria of Eaton and Floyd. 4 These results compare favorably with those of capsulodesis and palmar plate reinforcing procedures outlined earlier. The concerns of Kessler and Eiken that the palmar plate would stretch have not been substantiated in this study. Failures, when they occurred, were noted within the first 6 months. Two of these (Group 1 patients) were successfully revised. The failure was seen to be at the sesamoid metacarpal junction, where fusion or stable fibrous union had not occurred, rather than within the palmar plate. Adequate sesamoid bone remained for revision. All four failures occurred with the early technique, in which a pull-out suture was used. The use of a permanent suture is now advocated. However, prominent sutures needed removal in two cases due to tenderness. Other possible improvements in technique could be considered. It may be more appropriate to secure the sesamoid prior to insertion of the protective Kirschner wire across the MPjoint. This allows a better assessment of the tension within the reconstruction and more proximal placement of the sesamoid with greater MP joint flexion, if appropriate. MPjoint arthrodesis is an effective means of preventing h y p e r e x t e n s i o n when there are arthritic changes present within the joint. This is a most satisfactory procedure but does have the disadvantages of removing flexion at the MP joint and creating a longer lever arm based at the CMC joint. Therefore we believe that sesamoid arthrodesis is a superior procedure when the MPjoint is otherwise stable (in all planes other than in the hyperextension plane) and when more than 30~preoperative flexion is present. This study indicates that the preoperative range of flexion is largely maintained postoperatively. However, if less than 30 ~ preoperative flexion is present, then the small range of motion obtained after sesamoid arthrodesis is probably not functional and MP joint arthrodesis is indicated.
References 1. Zancolli EA. Structural and dynamic bases of hand surgery, 2nd ed. Philadelphia: JB Lippincott, 1979:212. 2. Zancolli EA. Claw hand caused by paralysis of the
:]38
Tonkin et al. / Sesamoid Arthrodesis of the Thumb
intrinsic muscles. A simple procedure for its correction. J Bone Joint Surg 1957;39A:1076-80. 3. Filler BC, Stark HH, Boyes JH. Capsulodesis of the metacarpophalangeal joint of the thumb in children with cerebral palsy. J Bone Joint Surg 1976;58A: 667-70. 4. Eaton RG, Floyd WE. Thumb metacarpophalangeal capsulodesis: an adjunct procedure to basal joint arthroplasty for collapse deformity of the first ray. J Hand Surg 1988;13A:461-5.
5. Schuurman AH, Bos KE. Treatment of volar instability of the metacarpophalangeal joint of the thumb by volar capsulodesis. J Bone Joint Surg 1993;18B: 346-9. 6. Kessler I. A simplified technique to correct hyperextension deformity of the metacarpophalangeal joint of the thumb. J Bone Joint Surg 1979;61A:903-5. 7. Eiken O. Palmaris longus tenodesis for hyperextension of the thumb metacarpophalangeal joint. Scand J Plast Reconstr Surg 1981 ;15:149-52.