Wrist position and extensor tendon amplitude following repair After primary repair of severed extensor tendons, various methods are used to limit tendon adhesions and avoid rupture. Early passive digital motion with wrist extension (a “reverse Kleinert” protocol) has been advocated. However, there are no data to support an optimum wrist position or to indicate how much finger motion may safely be permitted. In this study we used eight fresh cadaver limbs to measure extensor tendon gliding in Verdan’s zones 3 to 8 when active grip and passive extension were simulated at different wrist positions. We found that if the wrist is extended more than 21 degrees, the extensor tendon glides with little or no tension in zones 5 and 6 throughout full simulated grip to full passive extension, permitting “passive motion” exercises to minimize tendon adhesions without risking rupture. In addition, we found that up to 6.4 mm of tendon can be debrided safely and full grip can still be permitted postoperatively if the wrist is splinted at 45 degrees extension. (J HANDSURC1992;17A:268-71.)
Yoshitaka Minamikawa, MD, OS&Z, Japan, Clayton A. Peimer, MD, Buffulo, N.Y., Toshiya Yamaguchi, MD, Osaka, Japan, Nanci A. Banasiak, OTR, BufSalo, N.Y., Kenichi
Kambe,
Osaka, Japan, and Frances
Kleinert’. 2 and Duran3 have reported protocols to limit tendon adhesions and avoid rupture after primary repair of severed flexor tendons. After extensor tendon repair, however, there are various approaches to postoperative care, including early passive motion with wrist extension4* 5 (“ reverse Kleinert” technique) and static wrist extension with or without some joint flexion6-” With one exception,’ no one has reported on a comparison of wrist positions to evaluate how much (active/passive) finger motion can be safely permitted to obtain a satisfactory result in this injury. In our study, we analyzed the dynamic anatomy of the long digital extensors to study these clinical issues.
From the Division of Hand Surgery, Department of Orthopaedics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, and Kansai Medical University, Osaka. Japan. Received for publication March 12, 1991.
Dec. 18, 1990; accepted
in revised form
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: Clayton A. Peimer, MD, Hand Center of Western New York, Millard Fillmore Hospital, 3 Gates Circle, Buffalo, NY. 3/l/2%52
268
THE JOURNAL
OF HAND SURGERY
S. Sherwin,
Materials
Buffalo, N.Y.
and methods
X-ray analysis. Eight fresh-frozen cadaver arms were amputated at midhumerus and thawed at room temperature. Skin incisions were made along the common extensor of the long finger (EDU L), and the tendon was tagged with 4-O steel sutures at precise 1 cm intervals through minimal transverse incisions in the paratenon and retinacular ligament; the skin was sutured. Since the knots of the steel suture were buried in the tendon, natural gliding in the paratenon or tendon sheath was preserved. After the measurements on EDC/L were completed, the method was repeated sequentially for the other tendons so as to avoid confusion in individual tendon measurements. Except for the absence of muscular tone, the tendon condition is close to that of the living hand. A braided Dacron polyester suture was stitched into the digital pulp to simulate passive finger extension. The superficialis and profundus flexors were each attached to individual sutures at their musculotendinous junctions to permit simulation of active grip (flexion). The arm was secured to a loading apparatus by means of external-fixation pins into the radius and the olecranon, with care taken to avoid piercing forearm muscles or tendons. Another external fixation device was attached to the second metacarpal to position the wrist
Vol. 17A, No. 2 March 1992
Wrist position and extensor
tendon amplitude following
repair
269
Table I. Excursion of extensor tendons when each finger joint is flexed Tendon Extensor indicis Common extensor of Index Long Ring Small Extensor digiti minimi
MP joint (mm/ 10”)
PIP joint (mmll0”)
Full grip
1.3
0.6
15.9
1.4 1.6 1.5 1.2 1.1
0.6 0.5 0.6 0.6 0.4
18.0 19.2 17.8 14.5 13.0
(mm)
2.7mm/lOO Flex
These values are standardized to a 65 mm (average) third metacarpal-sized hand (i e.. values are relative to hand size).
60” 45” 30”
30’
/
/‘I
45
60”
5 10 15
(mm)
Table II. Average minimum number of stitches related to tensile strength, by zone
Zone
Average minimum number of 10-O nylon stitches to avoid rupture
Tensile strength with wrist at 4.5 degrees extension and full grip (gm)
4 5 6
8 4 2
17 1 0
in various angles of extension. Full “passive” digital extension and maximal “active” grip were simulated by traction on the appropriate sutures with the wrist at neutral and then also at 30 degrees and 45 degrees of extension. For each wrist position, the actual longitudinal movement of the metal tendon markers was measured directly from lateral radiographs and then analyzed (Table I). Tendon gliding. Next we maintained the fingers in full grip and moved the wrist (with the metacarpal fixator) to determine the wrist angle (position) at which the tendon markers in zone 8 began to move as the wrist was gradually flexed from full extension. Tension in the tendons. In a separate portion of the study. we sharply lacerated and tagged both cut ends of the EDC/L (in mid-zone 5) with additional 4-O steel suture markers. To determine whether tension existed in zones 4 to 6, we “connected” these repair markers by tendon repair with 10-O nylon stitches and then simulated active grip (Table II).
Results Radiographs. At neutral wrist position all tagged markers in Verdan’s zones 3 through 8 moved when
Fig. 1. Excursion of middle extensor tendon from wrist motion was measured by recording the markers in the tendon.
digital motion was simulated. At both 30 degrees and 45 degrees extension, there was little or no movement in zone 8. although there was slight excursion in zones 3 through 7. Tendon gliding. Extensor tendon gliding with the digits fully flexed began at an average angle of 21 degrees of wrist extension. In other words, at more than 21 degrees of extension there was no tendon motion in zone 8 at any time, even during the full range of digital motion. The excursion of the long finger extensor tendon was measured at 2.7 mm per 10 degrees of wrist change (Fig. 1). This value corresponds to a tendon lag (redundancy) in the zones distal to zone 8 when the wrist is extended more than 21 degrees. For example, at 45 degrees of wrist extension. an aggregate zone 8 extensor lag of 6.4 mm is present, whereas at 30 degrees of extension the lag averages 2.3 mm. Actually, posteroanterior and lateral radiographs show this redundancy as tendon buckling in the region proximal to the metacarpophalangeal joint (MP) and carpal bones (Fig. 2). Viewed from a surgical perspective, these data show that the maximum length of tendon that can be safely debrided is 6.4 mm when the wrist is splinted at 45 degrees of extension and full grip is still to be permitted. Further debridement would require that the range of digital flexion be restricted (postoperatively) to avoid tension at the repair site (Table I). Tension in the tendons. The average number of lo0 nylon stitches needed to avoid rupture is shown in Table II. At 45 degrees of extension, there was no significant tension in zone 6: the tension in zone 5 was
270
Minamikawa
The Journal of HAND SURGERY
et al,
Wrist Extension
Fig. 2. Longitudinal movement of the tendon markers as distance of each marker from the radius when the finger is flexed. Proximal five markers showed almost no motion when wrist was positioned at 30 degrees and 45 degrees of extension.
so little that a single 10-O suture was enough to prevent rupture. However, in zone 4 and more distally, tension did exist. We believe this was due to the tendon interconnections and tight surrounding tissues, which prevented transmission of the relaxation effect (from zone 7).
Discussion To recover maximum function after repair of lacerated (extensor) tendons, it is essential to preserve tendon gliding and at the same time prevent rupture. According to Duran,3 adhesions of flexor tendons can be avoided by permitting 3 to 5 mm of glide postoperatively, Our study reveals that if the wrist is fixed at 30 degrees or more of extension, the long finger extensor digitorum communis glides with little or no tension at zone 6 and minimal tension at zone 5 throughout the range of full simulated grip to full extension. These data verify that “reverse Kleinert” passive exercises can be used to minimize adhesions without risking rupture. Thus, if no debridement is performed on a lacerated tendon and if the wrist is extended 30 degrees, digital flexion blocks are neither necessary nor advisable. In active extension and flexion, excursion at MP joint level is directly proportional to angular changes in the joint.” There is actually less excursion when’ passive
extension and active grip are simulated because the extensor tendon just proximal to the MP joint is redundant in the passive extension position with wrist extended. Therefore, the estimate of Evans and Burkhaltels that angular motion of 38 degrees produces 5 mm of excursion is unduly optimistic. We believe that full grip and wrist extension are necessary to avoid adhesions and can now be noted to be safe from rupture. Actually, Browne and Ribik13 described a postoperative dorsal dynamic splint that permits full grip; in their clinical series they reported no ruptures and excellent motion. Our experimental results now provide a basis for those clinical observations. Postoperative care, which permits full grip at more than 22 to 30 degrees of wrist extension, can be applied to lacerations in zones 5 and 6 because tendon lag from wrist extension does not affect zone 4 or sites more distal inasmuch as the interconnections between tendons and surrounding tissues are tight. Redundant buckling occurred in zone 7 (carpals) when the wrist was extended to 21 degrees; thus this postoperative position would not be an effective angle from which to gain sufficient gliding. Nevertheless, the repair is absolutely safe from rupture. In zone 8 the tendon does not move when the wrist is extended more than 21 degrees. Therefore, in cases of laceration in zone 8. less than 21 degrees of extension is required
Vol. 17A, No. 2 March 1992
Wrist position
to avoid adhesions; however, there will still be slight tension. As there was a buckling proximally at the musculotendinous junction when the wrist was extended more than 10 degrees, we believe that, with in vivo muscle elasticity, 10 to 20 degrees of extension is adequate to protect a repair and allow full digital flexion. The results of this study provide clinical information concerning the rehabilitation of patients with this common injury. Conclusions Zones 5 and 6. The wrist should be fixed in more than 22 degrees of extension to produce tendon relaxation throughout the range of digital extension to full grip. Dynamic splinting permitting full grip is effective in prevention of both adhesions and rupture. Zone 7. The dorsal dynamic splint is not as effective in avoiding all potential adhesions (tendon redundant) but does safeguard the repair from rupture as buckling of tendons occurs in passive extension and disappears in full grip. Zone 8. The wrist should be fixed in 10 to 20 degrees of extension to gain tendon gliding without tension. The maximum tendon length that can be debrided is 6.4 mm if the wrist is splinted at 45 degrees of extension and full grip is to be permitted postoperatively. If more debridement is required, digital flexion should be restricted by flexion block (at the MP joint, each 10 degrees gains 1.4 mm; at the PIP joint, each 10 degrees gains 0.6 mm).
and extensor tendon amplitude
following
repair
271
REFERENCES 1. Kleinert HE, Kutz JE, Ashbell T, et al. Primary repair of flexor tendons in no-man’s_land. J Bone Joint Surg 1967;49A:577. 2. Kleinert HE. Primary repair of zone 2 flexor tendon lacerations. In: ASOS symposium on tendon surgery in the hand. St Louis: CV Mosby, 1975:91-104. 3. Duran RJ. Controlled passive motion following tendon repair in zones 2 and 3. In: AAOS symposium on tendon surgery in the hand. St Louis: CV Mosby, 1975: 105-14. 4. Evans RB, Therapeutic management of extensor tendon injuries. Hand Clinics. 1986;2: 157-69. 5. Evans RB, Burkhalter WE. A study of the dynamic anatomy of extensor tendons and implications for treatment. J HAND SURG 1986;l lA:774-9. 6. Blue AI, Spira M, Hardy SB. Repair of extensor tendon injuries of the hand. Am J Surg 1976;132:128-32. 7. Lovett WL. Management and rehabilitation of extensor tendon injuries. Orthop Clin North Am 1983;14:811. 8. Lee VH. Rehabilitation of extensor tendon injuries. In: Hunter JM. Schneider LH, Macklin EJ, Callahan AD, eds. Rehabilitation of the hand. 2nd ed. St. Louis: CV Mosby, 1984:353-7. injuries. In: Green 9. Doyle RD. Extensor tendons-acute DP, ed. Operative hand surgery. 2nd ed. New York: Churchill Livingstone, 1988:2045-72. 10. Tubiana R. Surgical repair of the extensor apparatus of the fingers. Surg Clin North Am 1968;48:1015-31. II. McFarlane RM. Treatment of extensor tendon injuries of the hand. Can J Surg 1973;16:366-75. 12. Boyes JH, ed. Bunnell’s surgery of the hand. 4th ed. Philadelphia: JB Lippincott, 1964: 13-20. 13. Browne EZ. Ribik CA. Early dynamic splinting for extensor tendon injuries. J HAND SURG 1989:14A:72-6.
Yoshitaka Minamikawa, MD, OS&Z, Japan, Clayton A. Peimer, MD, Buffulo, N.Y., Toshiya Yamaguchi, MD, Osaka, Japan, Nanci A. Banasiak, OTR, BufSalo, N.Y., Kenichi
Kambe,
Osaka, Japan, and Frances
Kleinert’. 2 and Duran3 have reported protocols to limit tendon adhesions and avoid rupture after primary repair of severed flexor tendons. After extensor tendon repair, however, there are various approaches to postoperative care, including early passive motion with wrist extension4* 5 (“ reverse Kleinert” technique) and static wrist extension with or without some joint flexion6-” With one exception,’ no one has reported on a comparison of wrist positions to evaluate how much (active/passive) finger motion can be safely permitted to obtain a satisfactory result in this injury. In our study, we analyzed the dynamic anatomy of the long digital extensors to study these clinical issues.
From the Division of Hand Surgery, Department of Orthopaedics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, and Kansai Medical University, Osaka. Japan. Received for publication March 12, 1991.
Dec. 18, 1990; accepted
in revised form
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: Clayton A. Peimer, MD, Hand Center of Western New York, Millard Fillmore Hospital, 3 Gates Circle, Buffalo, NY. 3/l/2%52
268
THE JOURNAL
OF HAND SURGERY
S. Sherwin,
Materials
Buffalo, N.Y.
and methods
X-ray analysis. Eight fresh-frozen cadaver arms were amputated at midhumerus and thawed at room temperature. Skin incisions were made along the common extensor of the long finger (EDU L), and the tendon was tagged with 4-O steel sutures at precise 1 cm intervals through minimal transverse incisions in the paratenon and retinacular ligament; the skin was sutured. Since the knots of the steel suture were buried in the tendon, natural gliding in the paratenon or tendon sheath was preserved. After the measurements on EDC/L were completed, the method was repeated sequentially for the other tendons so as to avoid confusion in individual tendon measurements. Except for the absence of muscular tone, the tendon condition is close to that of the living hand. A braided Dacron polyester suture was stitched into the digital pulp to simulate passive finger extension. The superficialis and profundus flexors were each attached to individual sutures at their musculotendinous junctions to permit simulation of active grip (flexion). The arm was secured to a loading apparatus by means of external-fixation pins into the radius and the olecranon, with care taken to avoid piercing forearm muscles or tendons. Another external fixation device was attached to the second metacarpal to position the wrist
Vol. 17A, No. 2 March 1992
Wrist position and extensor
tendon amplitude following
repair
269
Table I. Excursion of extensor tendons when each finger joint is flexed Tendon Extensor indicis Common extensor of Index Long Ring Small Extensor digiti minimi
MP joint (mm/ 10”)
PIP joint (mmll0”)
Full grip
1.3
0.6
15.9
1.4 1.6 1.5 1.2 1.1
0.6 0.5 0.6 0.6 0.4
18.0 19.2 17.8 14.5 13.0
(mm)
2.7mm/lOO Flex
These values are standardized to a 65 mm (average) third metacarpal-sized hand (i e.. values are relative to hand size).
60” 45” 30”
30’
/
/‘I
45
60”
5 10 15
(mm)
Table II. Average minimum number of stitches related to tensile strength, by zone
Zone
Average minimum number of 10-O nylon stitches to avoid rupture
Tensile strength with wrist at 4.5 degrees extension and full grip (gm)
4 5 6
8 4 2
17 1 0
in various angles of extension. Full “passive” digital extension and maximal “active” grip were simulated by traction on the appropriate sutures with the wrist at neutral and then also at 30 degrees and 45 degrees of extension. For each wrist position, the actual longitudinal movement of the metal tendon markers was measured directly from lateral radiographs and then analyzed (Table I). Tendon gliding. Next we maintained the fingers in full grip and moved the wrist (with the metacarpal fixator) to determine the wrist angle (position) at which the tendon markers in zone 8 began to move as the wrist was gradually flexed from full extension. Tension in the tendons. In a separate portion of the study. we sharply lacerated and tagged both cut ends of the EDC/L (in mid-zone 5) with additional 4-O steel suture markers. To determine whether tension existed in zones 4 to 6, we “connected” these repair markers by tendon repair with 10-O nylon stitches and then simulated active grip (Table II).
Results Radiographs. At neutral wrist position all tagged markers in Verdan’s zones 3 through 8 moved when
Fig. 1. Excursion of middle extensor tendon from wrist motion was measured by recording the markers in the tendon.
digital motion was simulated. At both 30 degrees and 45 degrees extension, there was little or no movement in zone 8. although there was slight excursion in zones 3 through 7. Tendon gliding. Extensor tendon gliding with the digits fully flexed began at an average angle of 21 degrees of wrist extension. In other words, at more than 21 degrees of extension there was no tendon motion in zone 8 at any time, even during the full range of digital motion. The excursion of the long finger extensor tendon was measured at 2.7 mm per 10 degrees of wrist change (Fig. 1). This value corresponds to a tendon lag (redundancy) in the zones distal to zone 8 when the wrist is extended more than 21 degrees. For example, at 45 degrees of wrist extension. an aggregate zone 8 extensor lag of 6.4 mm is present, whereas at 30 degrees of extension the lag averages 2.3 mm. Actually, posteroanterior and lateral radiographs show this redundancy as tendon buckling in the region proximal to the metacarpophalangeal joint (MP) and carpal bones (Fig. 2). Viewed from a surgical perspective, these data show that the maximum length of tendon that can be safely debrided is 6.4 mm when the wrist is splinted at 45 degrees of extension and full grip is still to be permitted. Further debridement would require that the range of digital flexion be restricted (postoperatively) to avoid tension at the repair site (Table I). Tension in the tendons. The average number of lo0 nylon stitches needed to avoid rupture is shown in Table II. At 45 degrees of extension, there was no significant tension in zone 6: the tension in zone 5 was
270
Minamikawa
The Journal of HAND SURGERY
et al,
Wrist Extension
Fig. 2. Longitudinal movement of the tendon markers as distance of each marker from the radius when the finger is flexed. Proximal five markers showed almost no motion when wrist was positioned at 30 degrees and 45 degrees of extension.
so little that a single 10-O suture was enough to prevent rupture. However, in zone 4 and more distally, tension did exist. We believe this was due to the tendon interconnections and tight surrounding tissues, which prevented transmission of the relaxation effect (from zone 7).
Discussion To recover maximum function after repair of lacerated (extensor) tendons, it is essential to preserve tendon gliding and at the same time prevent rupture. According to Duran,3 adhesions of flexor tendons can be avoided by permitting 3 to 5 mm of glide postoperatively, Our study reveals that if the wrist is fixed at 30 degrees or more of extension, the long finger extensor digitorum communis glides with little or no tension at zone 6 and minimal tension at zone 5 throughout the range of full simulated grip to full extension. These data verify that “reverse Kleinert” passive exercises can be used to minimize adhesions without risking rupture. Thus, if no debridement is performed on a lacerated tendon and if the wrist is extended 30 degrees, digital flexion blocks are neither necessary nor advisable. In active extension and flexion, excursion at MP joint level is directly proportional to angular changes in the joint.” There is actually less excursion when’ passive
extension and active grip are simulated because the extensor tendon just proximal to the MP joint is redundant in the passive extension position with wrist extended. Therefore, the estimate of Evans and Burkhaltels that angular motion of 38 degrees produces 5 mm of excursion is unduly optimistic. We believe that full grip and wrist extension are necessary to avoid adhesions and can now be noted to be safe from rupture. Actually, Browne and Ribik13 described a postoperative dorsal dynamic splint that permits full grip; in their clinical series they reported no ruptures and excellent motion. Our experimental results now provide a basis for those clinical observations. Postoperative care, which permits full grip at more than 22 to 30 degrees of wrist extension, can be applied to lacerations in zones 5 and 6 because tendon lag from wrist extension does not affect zone 4 or sites more distal inasmuch as the interconnections between tendons and surrounding tissues are tight. Redundant buckling occurred in zone 7 (carpals) when the wrist was extended to 21 degrees; thus this postoperative position would not be an effective angle from which to gain sufficient gliding. Nevertheless, the repair is absolutely safe from rupture. In zone 8 the tendon does not move when the wrist is extended more than 21 degrees. Therefore, in cases of laceration in zone 8. less than 21 degrees of extension is required
Vol. 17A, No. 2 March 1992
Wrist position
to avoid adhesions; however, there will still be slight tension. As there was a buckling proximally at the musculotendinous junction when the wrist was extended more than 10 degrees, we believe that, with in vivo muscle elasticity, 10 to 20 degrees of extension is adequate to protect a repair and allow full digital flexion. The results of this study provide clinical information concerning the rehabilitation of patients with this common injury. Conclusions Zones 5 and 6. The wrist should be fixed in more than 22 degrees of extension to produce tendon relaxation throughout the range of digital extension to full grip. Dynamic splinting permitting full grip is effective in prevention of both adhesions and rupture. Zone 7. The dorsal dynamic splint is not as effective in avoiding all potential adhesions (tendon redundant) but does safeguard the repair from rupture as buckling of tendons occurs in passive extension and disappears in full grip. Zone 8. The wrist should be fixed in 10 to 20 degrees of extension to gain tendon gliding without tension. The maximum tendon length that can be debrided is 6.4 mm if the wrist is splinted at 45 degrees of extension and full grip is to be permitted postoperatively. If more debridement is required, digital flexion should be restricted by flexion block (at the MP joint, each 10 degrees gains 1.4 mm; at the PIP joint, each 10 degrees gains 0.6 mm).
and extensor tendon amplitude
following
repair
271
REFERENCES 1. Kleinert HE, Kutz JE, Ashbell T, et al. Primary repair of flexor tendons in no-man’s_land. J Bone Joint Surg 1967;49A:577. 2. Kleinert HE. Primary repair of zone 2 flexor tendon lacerations. In: ASOS symposium on tendon surgery in the hand. St Louis: CV Mosby, 1975:91-104. 3. Duran RJ. Controlled passive motion following tendon repair in zones 2 and 3. In: AAOS symposium on tendon surgery in the hand. St Louis: CV Mosby, 1975: 105-14. 4. Evans RB, Therapeutic management of extensor tendon injuries. Hand Clinics. 1986;2: 157-69. 5. Evans RB, Burkhalter WE. A study of the dynamic anatomy of extensor tendons and implications for treatment. J HAND SURG 1986;l lA:774-9. 6. Blue AI, Spira M, Hardy SB. Repair of extensor tendon injuries of the hand. Am J Surg 1976;132:128-32. 7. Lovett WL. Management and rehabilitation of extensor tendon injuries. Orthop Clin North Am 1983;14:811. 8. Lee VH. Rehabilitation of extensor tendon injuries. In: Hunter JM. Schneider LH, Macklin EJ, Callahan AD, eds. Rehabilitation of the hand. 2nd ed. St. Louis: CV Mosby, 1984:353-7. injuries. In: Green 9. Doyle RD. Extensor tendons-acute DP, ed. Operative hand surgery. 2nd ed. New York: Churchill Livingstone, 1988:2045-72. 10. Tubiana R. Surgical repair of the extensor apparatus of the fingers. Surg Clin North Am 1968;48:1015-31. II. McFarlane RM. Treatment of extensor tendon injuries of the hand. Can J Surg 1973;16:366-75. 12. Boyes JH, ed. Bunnell’s surgery of the hand. 4th ed. Philadelphia: JB Lippincott, 1964: 13-20. 13. Browne EZ. Ribik CA. Early dynamic splinting for extensor tendon injuries. J HAND SURG 1989:14A:72-6.
