Results of acute zone III extensor tendon injuries treated with dynamic extension splinting

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7. Cauldwell EW, Anson BJ, Wright RR. The extensor indicis proprius muscle. Quart Bull Northwest Univ Mcd School 1943;17:267-79. 8. Jackson CM. Morris's Human Anatomy. 5th ed. Philadelphia: Blackistons' Son & Co, 1914:395. 9. LeDouble AF. Traite des Variations du Systeme Musculaire de I'Homme et de leur Signification au Point de Vue de l'anthropologie Zoologique. Paris: Schleicher Freses, 1897:203-17. 10. Straus WL. The phylogeny of the human forearm extensors. Human Bioi 1941;13:23-50,201-38. II. Wagenseil F. Untersuchungen tiber die Muskulatur der Chinesen. Ztschr f Morphol u Anthropol 1936;36:39150. 12. Kaneff A. Vergleichend-morphologische Untersuchung des Fingerstreckers, M. extensor digitorum, beim Men-

Extensor medii proprius and anomalous extensor tendons

13. 14. 15.

16.

17.

schen und einigen Saugern. Morphol Jb 1960;100:488516. McGregor AL. A contribution to the morphology of the thumb. J Anat 1926;60:259-73. Ayer AA. The anatomy of semnopithecus entellus. Madras, India: Indian Publishing House, 1948:60. Howell AB, Straus WL. The muscular system. In: Hartman CG, Straus WL, eds. Anatomy of the rhesus monkey. New York: Hafner Publ Co, 1961:89-175. Schultz M. The forelimb of colobinae. In: Swindler DR, Erwin J, eds. Comparative primate biology. New York: Alan R. Liss Inc, 1986:559-669. Sonntag CF. The morphology and evolution of the apes and man. London: J. Bales, Sons & Danielsson Ltd, 1924: 190-1.

Results of acute zone III extensor tendon injuries treated with dynamic extension splinting Motivated by the favorable results of dynamic splinting in the treatment of more proximal extensor tendon injuries, we explored the use of dynamic splinting in the treatment of zone III extensor tendon lacerations. Twenty-two tendon repairs in 19 patients were available for review. On the basis of degree of extension lag and pulp-to-palm distance, 14 repairs were rated as excellent, 6 as good, and 2 as fair. Using total active motion at 10 weeks, the proximal interphalangeal and distal interphalangeal joints averaged 170 degrees. There was one mild boutonniere deformity. The results of this prospective study show that carefully monitored dynamic splinting is safe in the treatment of zone III lacerations. When results were compared with the results of our method of static splinting used prior to this prospective study, patients returned to full activities with good-to-excellent results 8 weeks earlier instead of at 16 to 18 weeks. (J HArm SURG 1991;16A:114S-S0.)

CAPT Miguel J. Saldana, MC, USN, LCDR Stephen Choban, MC, USNR, LT Peggy Westerbeck, MSC, USNR, and CDR Timothy G. Schacherer, MC, USN, Portsmouth, Va.

From the Naval Hospital Portsmouth, Department of Orthopedics, Division of Hand Surgery, Portsmouth, Va. Received for publication April 18, 1990; accepted in revised form Nov. 2, 1990. 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: CAPT Miguel J. Saldana, Me, USN, Naval Hospital Portsmouth, Department of Orthopedics, Division of Hand Surgery, Portsmouth, VA 23708. 3/1127515

Classic treatment of central slip lacerations in extensor zone lIP has included either percutaneous pin fixation or splinting of the proximal interphalangeal (PIP) joint in extension after repair.v 3 Extensor zone III involves the PIP joint area only. This form of immobilization has led to prolonged rehabilitation, decreased range of motion (ROM), and frequent lengthy delays in resumption of full activities. Motivated by the favorable results of dynamic splinting in flexor tendon injuries"? and more proximal exTIlE JOURNAL OF HAND SURGERY

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Table I. Classification Injury

Number of tendons

Lateral band only Partial central slip ± triangular ligament Complete central slip ± triangular ligament Central slip and lateral band Both lateral bands and central slip

A

BI

82 C

o

3 10 8 I

Treatment

Buddy tape x 4 wk Six weeks dynamic extension Six weeks dynamic extension Six weeks dynamic extension Six weeks dynamic extension

Table II. Treatment protocol Week

MCP joint (degrees)

PIP joint

One

30

Aluminum splint

Two Three Four Five

45

Six

90

Aluminum splint Aluminum splint Leather yoke under PIP Leather yoke under middle Leather yoke under middle phalanx Splint discontinued Mild resistive exercises to full activity by week 12

60 60 90

Seven and eight Nine through twelve

tensor tendon lacerations in extensor zones V through VIII,8.9 we examined the possible use of postoperative extensor dynamic splinting in the treatment of extensor tendon lacerations in zone III. Materials and methods All patients with simple lacerations involving extensor zone lIP seen at the Naval Hospital, Portsmouth, Virginia between January 1986 and January 1989 were entered in this prospective study. Patients with associated fractures or tissue loss were excluded. The patients were examined in the orthopaedic clinic where the wounds were initially explored. Lacerated tendons were repaired using figure-of-eight 4.0 Ethibond braided sutures under (X 2.5) loupe magnification. A standard hand dressing was applied with the lacerated finger splinted in extension. Referral to the Occupational Therapy Department for dynamic splinting was done within 3 days of injury. Lacerations were classified into types A, B, C, and D, depending on involvement of the extensor tendon and/or lateral bands in zone III. See Table I. Types B, C, and D were all treated with a 6-week dynamic extension protocol followed by a four- to eight-week gradual increase in grip strengthening monitored by the Occupational Therapy Department. See Table II.

DIP joint Full flexion 10 x per hour while awake holding PIP extended Same as week I Same as week I Same as week I Same as week I Same as week I No resistive grip activities

Two to 3 days after the injury the digit was placed in a dorsal finger extension assisted splint with the wrist at 35 to 45 degrees of extension. A leather finger yoke loop was placed beneath the affected PIP joint and a small aluminum splint was placed to prevent flexion of the PIP joint only. (See Fig. I.) During the first week in the splint the patient was instructed in active metacarpophalangeal (MCP) joint flexion to 30 degrees using the splint to bring the digit dynamically to full extension. No PIP joint flexion was permitted. While awake, patients were directed to perform active distal interphalangeal (DIP) flexion exercises. Holding the PIP firmly in extension with the aluminum splint in place and the thumb over the dorsum of the PIP, the DIP joint was flexed IO times per hour. During the second week the MCP joint flexion was increased to 45 degrees with the PIP joint still maintained in extension. Distal interphalangeal exercise was the same as in the first week. From days 15 through 21 MCP motion was increased to 60 degrees. Distal interphalangeal exercises were the same. At the start of the fourth week the aluminum splint was removed. The leather yoke was placed directly under the PIP and the patient permitted active flexion of the MCP joint to 60 degrees, maintaining splint assisted extension. During the fifth and sixth weeks the patients were allowed MCP joint flexion to 90 degrees with dynamic exten-

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Acme zone III extensor tendon injuries

Fig. 1. A·B, Dorsal dynamic splint with lead bead on lO-pound test fish line (small arrow) allowing 45 degrees of MCP flexion during second week of 6-week protocol. Note aluminum splint under leather yoke (large arrow) that prevents PIP flexion. The splint has 30 degrees of extension at the wrist.

Fig. 2. A, Patient 8 showing full extension of long and small fingers. The long finger has a type B2 injury and the small finger had a type C injury. B, Finger flexion at 8 weeks after injury. Ring finger has PIP bony ankylosis.

Fig. 2 (Cont'd). C, Finger extension 4 months after Swanson PIP arthroplasty. D, Finger flexion at 4 months after Swanson PIP arthroplasty.

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Table III. Results Final ROM (degrees) Patient

Digit

Hand

Injury

MP

1 2

RIll RII LlI RV LIlI RIV LlI RIll RV RIll LV RIll LII LIV LV RV L IV RIV LIV RIll RV LIV

Dominant Dominant Nondominant Dominant Nondominant Dominant Nondominant Nondominant Nondominant Dominant Nondominant Dominant Nondominant Nondominant Nondominant Dominant Nondominant Dominant Nondominant Dominant Dominant Nondominant

100% CS + RLB 25% CS + RLB 100% CS 100% CS 100% CS + ULB 100% CS 100% CS 100% CS 100% CS + ULB 90% CS + RLB 100% CS 100% CS 100% CS + ULB 100% CS 100% CS 100% CS 100% CS 20% CS + ULB 100% CS 100% CS 100% CS + RLB 100% CS + Rand ULB

0-85 0-100 0-95 0-85 0-90 0-85 0-85 0-95 0-90 0-90 0-90 0-85 0-75 0-90 0-90 0-90 0-85 0-90 0-85 0-90 0-90 0-85

3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19

I

PIP

0-110 0-115 0-110 5-105 20-100 5-90 0-115 0-100 0-100 0-90 0-90 0-90 0-65 0-105 5-95 10-85 10-100 0-100 0-100 0-85 0-90 0-85

I

DIP

0-70 0-45 0-85 0-85 0-75 0-80 0-70 0-65 0-65 0-80 0-80 0-80 0-65 0-80 0-80 0-90 0-70 0-70 0-70 0-60 0-65 0-60

'Strickland and Glogovac." tDargan. 1o

sion, always with the leather yoke under the PIP. The DIP exercises were done by blocking the PIP in extension. See Table II. Twenty-one patients with 24 zone III lacerations were entered into the study. Two patients were lost to followup, leaving 19 patients with 22 zone III lacerations. Patients included 18 men and 1 woman. The lacerations were evenly divided between digits II through V. Patients were followed twice weekly by the Hand Service for the first 6 weeks and then weekly for an additional 2 months or until the patient was returned to full duty. In addition, the patients were followed in occupational therapy three times per week while on the protocol. There were 15 patient charts kept by the Occupational Therapy Department for zone III lacerations from January 1984 to December 1985. During that period of time the involved fingers were casted in extension for a period of 6 weeks before active ROM was begun. Final ROM and grip strength measurements were available for comparison. Case report A 32-year-old active-duty lieutenant injured the dorsal aspect of his right long, ring, and small fingers in zone III with

a table saw. The long finger sustained a 100% central slip laceration (type H2). The ring finger was excluded because there was bony involvement of the PIP joint. The small finger sustained a 100% central slip laceration and an ulnar lateral band laceration (type C). All injuries were repaired in the orthopaedic cast room with interrupted figure-of-eight sutures using 4-0 braided Ethibond. He was referred to the Occupational Therapy Department within 2 days. The 6-week dynamic extension protocol was employed on the long and small fingers. At 8 weeks he had no extension lag of his long and small fingers. His ring finger PIP joint formed a bony ankylosis and he subsequently had a Swanson arthroplasty of that joint (Fig. 2).

Results Final results are summarized in Table III. Sixteen fingers displayed no extension lag at the PIP joint while the remaining six fingers averaged nine degrees of extension lag (range, 5 to 20 degrees). Sixteen fingers were able to flex to the midpalmar crease while the remaining six fingers all came to within 2 em of the palm with active flexion. Average time until return to full activity was 8 to 9 weeks (range, 5 to 16 weeks). The results were divided into four categories: excellent, good, fair, and poor, based on a modification of the scheme used by Dargan'? in 1969 (Table IV). Using

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Acllte zone III extensor tendon injuries

Extension lag (degrees)

TAM' 170 160 190 185 155 165 185 165 165 170 170 175 130 185 180 165 160 170 170 155 150 150

Return to duty/work

Pulp/palm distance

0 0 0 5 20 5 0 0 0 0 0 0 0 0 5 10 10 0 0 0

0 I 0 0 0 0 0 0 0 0 0 0 2 0 I 0 .5 0 .5 0 0 0 0

0 0

5 10 12 8 9 8 8 8 8 15 12 8 9 8 8 16 6 8 7 5 5 9

em

cm

ern em em

0

wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk wk

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Functional resultt Excellent Good Excellent Good

Fair Good Excellent Excellent Excellent Excellent Excellent Excellent

Fair Excellent Good Good Good Excellent Excellent Excell ent Excellent Excellent

Table IV. Data sheet

Result

Extension lag (degrees)

Pulp -to-palm distance (cm)

Numb er offingers -

o

o

14


6

Fair

1-15 16-45

Poor

>45

>2

o

Excellent Good

this system there were 14 excellent, 6 good, and 2 fair results. No patient had a poor result and of the 2 fair results, I patie nt (patient 5, Tab le Ill) had an extensive injury involving the ulnar digital nerve and the ulnar slip of thesuperficialis tendon . There was one mild boutonniere deformity. No patient required tenoly sis. The average length of treatment on the 15 patients whose charts were reviewed was 15 weeks . There were eight patients with a total active motion of 135 degrees, two patients with tota l act ive motion of 120, and five patients with 100 degrees or less. Only three patients' fingers reached the midpalmar crease at the end of therapy. Three of the five patients with a ROM of less than

2

100 degrees were discharged from the military because of persistent chronic boutonniere deformity. There were six boutonniere deformities, three chronic and fixed and three mild. Average grip strength on the involved hand was 60% of the uninvolved hand. Discussion Rehabilitation after repair of central slip lacerations requires a delicate balance between immobilization to relieve stress on the repair and early motion to regain function. The rationale for immobilization stemmed from the unique anatomy of the extensor apparatus . II The flattened shape of the extensor tendon as it passes over the PIP joint makes anatomic repairs difficult . The

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central slip glides forward in flexion of the PIP while the lateral bands are displaced palmarly and also distally. The movement is reversed in extension of the PIP, as first described by Winslow.'! Central slip excursion at the level of the PIP joint averaged 4.4 mm for the small, 7.3 mm for the ring, 6.7 mm for the index and 7.5 mm for the long finger. These averages were computed after the dissection of 10 fresh cadavers on which 5800 different measurements were made (DeVoll and Saldana, unpublished data). The flattened tendon over zone III is exquisitely sensitive to changes in tendon length, both at the time of the repair and during subsequent rehabilitation. Attenuation of the repair leads to an unopposed PIP flexion force by the superficialis and profundus tendons. Palmar migration of the lateral bands, intrinsic tendon overpull directed at the PIP joint, and shortening of the oblique retinacular ligament and triangular ligament results in the classic boutonniere deformity.": 14 Fear of the development of a boutonniere deformity has led to recommendations for various forms of rigid immobilization in the treatment of this injury. Adhesion of either the central slip and/ or the lateral bands leads to restrictive extension and flexion. Advocates of early motion in proximal zone injuries, conversely, point out that controlled passive motion has significant beneficial effects in rehabilitation after tendon repairs, including improved tensile strength and glide characteristics while reducing adhesions." IS The rehabilitation protocol we used was designed to combine early controlled motion of the MCP joint with nonrigid immobilization of the PIP joint in an attempt to improve function without increasing the incidence of boutonniere deformities. The micromotion of the extensor apparatus in zone III held in extension while the MCP joint is allowed to flex should theoretically decrease adhesions. The overall total active motion was 170 degrees in the tendons involved in the prospective study. Measurements were done in the first position. By employing Strickland's flexor tendon total active motion criteria to evaluate these extensor injuries, the more strict evaluation of finger function was performed. The elimination of the MCP joint motion aIlows one to evaluate ROM of the PIP and DIP only. With the exception of patient 5 (Table III), previously described immobilization of the PIP joint in this study was rigid enough to prevent the development of functionally significant extension lag and in all cases, except one, prevent formation of boutonniere deformities. Total active motion of the PIP and DIP joints averaged 170 degrees at 8 weeks. Return to fuIl duty was accomplished on the average in 8 to 10 weeks after surgical repair, substantiating the value of early motion in the rehabilitation of this complex injury.

REFERENCES 1. Kleinert HE, Schepel S, Gill T. Flexor tendon injuries. Surg C1in North Am 1981;61:267-80. 2. McFarlane RM, Hampole MK. Treatment of extensor tendon injuries of the hand. Can J Surg 1973;16:366-75. 3. Sakellarides HT. The extensor tendon injuries and their treatment. RIMed J 1978;61:307-13. 4. Strickland JW, Glogovac SV. Digital function following flexor tendon repair in zone II: A comparison of immobilization and controlled passive motion techniques. J HAND SURG 1980;5:537-43. 5. Lister GD, Kleinert HE, Kutz JE, et al. Primary flexor tendon repair followed by immediate controlled mobilization. J HAND SURG 1977;2:441-51. 6. Kleinert HE, Kutz JE, Asbell TS, et al. Primary repair in zone 2 and 3. In: AAOS symposium on tendon surgery in the hand, Philadelphia, 1974. St. Louis: CV Mosby, 1975:91-104. 7. Chow JA, Thomes U, Dovelle S, et ai. Controlled motion rehabilitation after flexor tendon repair and grafting. J Bone Joint Surg 1988;70B:591-5. 8. Browne EZ, Ribik CA. Early dynamic splinting for extensor tendon injuries. J HAND SURG 1989;14A:72-6. 9. Chow JA, Thomes U, Dovelle S, et al. A comparison of results of extensor tendon repair followed by early controlled mobilization vs. static immobilization. J HAND SURG 1989;14B:18-20. 10. Dargan EL. Management of extensor tendon injuries of the hand. Surg Gynecol Obstet 1969;128:1269-73. 11. Zancolli EA. Structural and dynamic basis of hand surgery. Philadelphia: JB Lippincott, 1968:23-37. 12. Winslow JB. Exposition anatomique de la structure du corps humain. Ed. 2. Amsterdam; 1752. 13. Froehlich JA, Akelman E, Herndon JH. Extensortendons in injuries at the proximal interphalangeal joint. Hand Clin 1988;4:25-37. 14. Evans RB, Burkhalter WE. A study of the dynamic anatomy of extensor tendons and implications for treatment. J HAND SURG 1986;I1A:774-9. 15. Duran RE. Controlled passive motion following flexor tendon repair in zone two and three. In: AAOS: Symposium on tendon surgery in the hand. St. Louis: CV Mosby, 1975:105-14. 16. Nisenbaum M. Early care of flexor tendon injuries: Application of principles of tendon healing and early motion. In: Hunter JM, Schneider LH, Mackin EJ, et al., eds. Rehabilitation of the hand. St. Louis: CV Mosby, 1978:187-96. 17. Mason JW, Allen HS. The rate of healing of tendons: an experimental study of tensile strength. Ann Surg 1941;113:424-59. 18. Madden JW. Wound healing: the biological basis of hand surgery. In: Hunter JM, Schneider LH, Mackin EJ, et al., eds. Rehabilitation of the hand, St. Louis: CV Mosby, 1978:105-12.