Flexor digitorum profundus tendongrafting (extrasynovial donor tendons)

Flexor digitorum profundus tendongrafting (extrasynovial donor tendons)

FLEXOR DIGITORUM PROFUNDUS TENDON GRAFTING (EXTRASYNOVIAL DONOR TENDONS) JEFFREY A. GREENBERG, MD, MS Although the prevalence of flexor tendon grafti...

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FLEXOR DIGITORUM PROFUNDUS TENDON GRAFTING (EXTRASYNOVIAL DONOR TENDONS) JEFFREY A. GREENBERG, MD, MS

Although the prevalence of flexor tendon grafting has decreased since the early part of this century, the technique is still an important part of a hand surgeon's armamentarium. Primary and staged flexor tendon grafting are appropriate techniques used to restore digital function after failed or neglected repairs. Appropriate patient selection, meticulous reconstructive techniques, and respect for basic biological principles of healing and repair are essential elements for successful tendon grafting. KEY WORDS: flexor tendon, tendon grafting, hand, injuries, surgery

During the early part of this century, tendon grafting was the treatment of choice for an acute flexor tendon injury in the flexor sheath. 1 This recommendation was based on poor results of primary tendon repair. However, the overall prevalence of flexor tendon grafting has greatly declined as our understanding of flexor tendon healing has improved, as we have developed improved suture materials and surgical techniques, and as structured rehabilitation programs, emphasizing early protected range of motion have been implemented. 2-4 Despite the recent success of primary flexor tendon repair, tendon grafting remains an important component of the hand surgeon's armamentarium. Tendon grafting is frequently used to restore digital function after failed or neglected repairs. Extrasynovial tendon grafting is the most common technique used today and refers to using an extrasynovial donor graft. The three most common sources of extrasynovial donor tendons are the palmaris longus, plantaris, and extrinsic long toe extensors. Contrast this with intrasynovial sources such as the flexor digitorum longus, which is discussed in another chapter in this issue. There is recent biological evidence supporting the use of intrasynovial grafts. 5,6

INDICATIONS Flexor tendo~L grafting can be considered in any patient that requires restoration of flexor function in a damaged digit. A very important prerequisite for either primary or staged reconstruction is a motivated patient who not only understands the complexity of reconstruction but is willing and able to participate actively in the postoperative rehabilitation associated with the surgery. Patients must be made aware of the possibility of multiple operative proce-

From The Indiana Hand Center, Indianapolis, IN.

Address reprint requests to JeffreyA. Greenberg, MD, MS, The Indiana Hand Center, 8501 Harcourt Road, Indianapolis, IN 46260. Copyright © 1998 by W.B. Saunders Company 1048-6666/98/0802-0007508.00/0

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dures that may be required in an attempt to achieve a functioning flexor tendon system. Less favorable results are achieved in digits after crush injuries or injuries associated with neurovascular compromise, 7,8 and patients need to be aware of limited expectations depending on the initial injury. 9 General prerequisites for consideration of tendon grafting include an age greater than 3 years old, a well-vascularized digit with at least one intact digital nerve, and adequate supple soft tissue coverage. 1°.11 Primary tendon grafting can be considered in any patient with compromised tendon function that maintains a supple digit, retains a healthy soft tissue bed, and an intact retinacular system in which to receive the graft. Most frequently, candidates for primary flexor tendon grafting present greater than 3 weeks postinjury. Tendon retraction and degeneration has occurred precluding delayed primary repair, but the flexor tendon sheath has remained intact or can be restored at the time of repair to allow primary grafting. Staged flexor tendon reconstruction is used in those patients that require flexor function but do not meet the requirements for primary grafting. The presence of joint contracture, an inadequate, collapsed, or scarred retinacular pulley system, an unhealthy bed for receipt of an avascular graft, prior sepsis, and poor soft tissue coverage are usually conditions that dictate the performance of staged grafting. During the first stage of a staged procedure, full passive range of motion is established by releasing all joint contractures. In cases with long-standing contractures, soft tissue coverage may need to be addressed. A functional pulley system is reconstructed around a silicone rod, which replaces the scarred, damaged, and contracted flexor tendon elements. The biological formation of a mesotheliallined pseudosheath around the silicone rod, in conjunction with discrete annular pulley reconstruction, facilitates restoration of gliding mechanics required for digital recovery. Maintenance of passive range of motion allows for secondary grafting usually 3 to 6 months after the first stage. Prerequisites for proceeding to tendon grafting include recovery of passive range of motion, resolution of Operative Techniquesin Orthopaedics.Vol 8, No 2 (April), 1998: pp 98-105

Fig 1. (A) A longitudinal incision medial to the Achilles tendon is used to harvest the plantaris tendon. (B) The tendon is localized as illustrated in the photograph. (C) A tendon stripper facilitates harvesting of the tendon. The suture at the distal end of the tendon enables handling of the tendon using a "no-touch" technique. (D) The tendon graft is now ready for transfer to the hand, EXTRASYNOVIAL FLEXOR TENDON GRAFTING

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for graft harvesting. Care is taken not to touch the tendon with gloved hands (Fig 1D). The long toe extensor of ~ e second and third toe is used if the palmaris longus or plantaris is not available as donor

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Fig 2. The midllateral approach with extension into the palm is recommended to keep cutaneous scarring lateral to the flexor tendon sheath. (Copyright © by The Indiana Hand Center.)

edema, development of supple wounds, and quiescence of scar reactivity. TECHNIQUE Tendon Selection

The palmaris longus is the most frequently used tendon for grafting. The tendon averages 3 m m in width and usually provides enough length for a single digit. Frequently in staged reconstructions the palmaris longus is used for pulley reconst:ruction and is not available. In addition, the palmaris longus may be absent in as many as 25% of upper extremities with a 28% chance of contralateral absence. 12,13 The plantaris provides a thinner graft than the palmaris longus but has a greater length making it applicable for a long graft or situations requiring multiple grafts. Absence of the plantaris is estimated at 19% with a higher chance of contralateral absence estimated at 44%. Both the palmaris longus and plantaris are easily obtained via single incisions and the use of a tendon stripper. A transverse incision at the wrist flexion crease is used to obtain the palmaris longus whereas a longitudinal incision just anterior to the medial aspect of the Achilles tendon is used for the plantaris (Fig 1A). When obtaining the palmaris longus tendon, care is taken to identify and protect the median nerve. The plantaris tendon is localized adjacent to the Achilles t e n d o n on the medial side of the ankle (Fig 1B). A Brartd tendon stripper facilitates harvesting of the tendon (Fig 1C). The stripper severs the tendon at the musculotendinous junction and precludes the use of multiple incisions 100

Fig 3. (A) The distal juncture of the graft is anchored to the distal phalanx using a transosseous suture, which exits dorsally through the nail plate distal to the germinal matrix. (B) The profundus remnant is used to reinforce the distal juncture. (Copyright © by The Indiana Hand Center.) JEFFREYA. GREENBERG

done via a midlateral or Brunner-type approach. Surgeon preference dictates incision choice; however, recognition of prior trauma, previous incisions, and soft tissue coverage after contracture release all dictate the approach to a damaged digit. A midlateral approach (Fig 2) develops a broad-based vascularized flap. The main advantage of a midlateral approach is that the resultant incision and cutaneous scar remains lateral to the tendon sheath.

SURGICAL TECHNIQUE PrimaryTendon Grafting Bunnell's classic article in 1918 laid the framework for technical aspects of tendon grafting and the majority of his recommendations hold true today. 1 Technical aspects and criteria regarding staged versus primary tendon grafting have also been recommended by contemporary investigators. 14 The appearance and function of the digital sheath is a great determinant as to whether the surgeon can proceed with primary tendon grafting. If the tendon sheath is

Fig 4. Manual traction on the tendon graft produces full flexion indicative of an intact retinacular system.

grafts. These tendons can be obtained via multiple small transverse incisions on the dorsum of the foot and a tendon stripper proximal to the retinaculum on the anterior aspect of the ankle. Multiple juncturae must be severed for distal harvest of the extensor tendons. Less frequent sources of graft material include the extensor digiti quinti proprius, extensor indicis proprius, and the injured flexor digitorum superficialis in a digit requiring grafting of the flexor digitorum profundus. Harvesting of the tendon must be as atraumatic as possible. An absolute "no-touch" technique is used. Debridement of thickened paratenon and adherent subcutaneous tissue and muscle is recommended although debridement of the surface of the tendon graft is controversial. Minimal debridement is recommended to lessen the chance of damage to the surface of the tendon graft, which will promote tendon adhesions.

SURGICAL INCISION Exposure of the digit for primary tendon grafting or during the first stage of a staged reconstruction may be EXTRASYNOVIAL FLEXOR TENDON GRAFTING

Fig 5. Tension of the graft should be adjusted so that the injured digit assumes a flexion posture slightly greater than the normal cascade.

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Fig 6. (A) Artist's rendition of an injured digit with a scarred, inadequate pulley system. (B and C) Diagram and clinical photograph of a first stage reconstruction with annular pulleys reconstructed over a silicone rod. (Copyright © by The Indiana Hand Center.)

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JEFFREY A. GREENBERG

Fig 7. During stage II the silicone rod is located in the distal forearm. A suture (arrow tip) has been used during stage I to facilitate identification of the donor motor during Stage II.

silicone prosthesis to encourage development of a pseudosheath that will be able to accept a tendon graft at a later stage (Fig 6). The silicone rod is anchored distally during stage I to prevent migration and placed deep to the FDS in the distal forearm. In addition, tagging of the proposed motor with a heavy colored suture facilitates identification during stage II (Fig 7). It is important to achieve preoperative passive range of motion after stage I. Passive range of motion exercises are initiated at 3 to 5 days postoperatively. Before proceeding with tendon graft replacement of the silicone rod, tissue equilibrium must be established. This is shown by good passive range of motion, resolution of edema, and softening of digital scar. In stage II only the proximal and distal portions of the previous wounds are used (Fig 8). The silicone rod is identified as is the donor motor. After the tendon graft is obtained, the distal end is sutured to the rod, which is then extracted distally, carrying the narrower end of the graft

relatively unharmed and the majority of the pulleys, including A2 and A4, are intact, then pulley reconstruction is not necessary. The sheath must be flexible enough to allow dilation, if constricted, and passage of the tendon graft; otherwise alternative techniques need to be considered. All scarred, adherent elements of the injured tendon system are removed. This can be facilitated using retinacular windows created between the annular pulleys in the membranous portion of the sheath. Preservation of as much sheath as possible is recommended. If there has been no injury or prior surgery in the palm then the junctures for the graft can be from tip to palm. This is frequently the case when primary grafting is performed 3 to 6 weeks after flexor tendon injury. However, in most cases the graft junctures are located proximally in the distal forearm and distally in the distal phalanx of the injured digit. Once the tendon graft is obtained, a suture is placed in the distal end of the donor tendon to handle the tendon using a "no-touch" technique. In primary grafting cases it is helpful to pass a pediatric feeding tube through the dilated tendon sheath and into the palm or forearm deep to the transverse retinacular ligament depending on the location of the proximal juncture. ~5 The graft can then be sutured to the feeding tube and withdrawn from proximal to distal through the sheath. The distal juncture is performed using a 2-0 prolene suture in a Bunnell fashion. A suture double armed with Keith needles facilitates suturing. The suture is passed through drill holes in the distal phalanx, which exits dorsally through the nail plate and is tied over a sterile button. The germinal matrix should not be injured. The stump of the profundus is used to reinforce the distal juncture (Fig 3). The adequacy of the tendon sheath can be assessed using manual traction on the graft (Fig 4). Proximall~ the juncture is performed in a Pulvertaft weave fashion through the selected motor. Tension is set so that the digit assumes a posture of slightly greater flexion than the resting posture of the ulnar digits (Fig 5).

STAGED RECONSTRUCTION A staged technique requires reconstruction of an adequate pulley system, release of contracture, and implantation of a EXTRASYNOVIAL FLEXOR TENDON GRAFTING

Fig 8. Only the proximal and distal ends of previously used incisions are necessary during the second stage of a staged reconstruction.

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/ Fig 9. Artist's ,depiction and clinical intraoperative photograph showing passage of the tendon graft during stage II. The tendon graft has been sutured to the silicone rod (A and B) and is advanced distally through the pseudosheath using gentle traction on the silicone rod (C). The rod can then be discarded and junctures made in the distal forearm and distal phalanx (D). (Copyright © by The Indiana Hand Center.)

through the pseudosheath to the distal phalanx (Fig 9A-C). The silicone rod can then be discarded and junctures can be made as previously described (Fig 9D). Postoperativel~ the patient's hand is immobilized in a bulky compression dressing. Early mobilization, although not improving final range of motion, may lower the rate of graft rupture and the incidence of tenolysis. 16 Gentle passive range of motion exercises are initiated at 3 to 5 days postoperatively. Active range of motion is initiated at 3 to 4 weeks with full use allowed at 12 weeks after surgery.

PITFALLS AND COMPLICATIONS The most common complication after tendon grafting is the development of adhesions, which prevent gliding of the graft. Adhesions have been shown at the proximal juncture as well as between the graft and pseudosheath. 17-~9The incidence of tenolysis may be as high as 47%. TM Tenolysis can be considered once adequate healing has occurred. Biological quiescence and tissue equilibrium are requisites for tenolysis. Rupture of the proximal or distal juncture must be recognized early. An open and honest discussion after rupture occurs must be held with the patient as one decides whether to continue to try and restore a functioning tendon system or proceed with a salvage procedure. A graft placed too short or with too m u c h tension may cause secondary contractures and a graft too long may lead to paradoxical extension. 2°,21 In stage I synovitis with resultant w o u n d breakdown may be encountered, which would require early silicone implant r e m o v a l . 19

CONCLUSION Management of the neglected, scarred, injured digit is much more difficult than primary or delayed primary repair and all efforts should be directed at primary repair of an injured flexor system. However, by applying modern surgical principles of management and rehabilitation and with the application of meticulous technique, great functional improvement can be achieved using flexor tendon grafts. Appropriate patient selection, meticulous reconstruction of scarred and injured elements, and respect for biological principles are essential elements in satisfactory restoration of a mobile digital flexor-retinacular system.

EXTRASYNOVIAL FLEXOR TENDON GRAFTING

REFERENCES 1. Bunnell S: Repair of tendons in the fingers and description of 2 new instruments. Surg Gynecol Obstet 26:103-110, 1918 2. Cannon NM, Strickland JW: Therapy following flexor tendon surgery. Hand Clin 1:147-164, 1985 3. Stewart KM: Reviews and comparison of current trends in the postoperative management of tendon repair. Hand Clin 7:447-460, 1991 4. Strickland JW: The Indiana method of flexor tendon repair. Atlas Hand Clin 1:77-10% 1996 5. Seiler J, Reddy A, Simpson L, et al: The flexor digitorum longus: An anatomic and microscopic study for use as a tendon graft. J Hand Surg [Am] 20:492-495, 1995 6. Seiler JG, Gelberman RH: Tendon grafting to the synovial spaces of the hand: A biologic basis for the selection of donor tendon, in Hunter JM, Schneider LH, Mackin EJ (eds): Tendon and Nerve Surgery in the Hand. St. Louis, MO, Mosby-Year Book, 1997, pp 404-409 7. Boyes J: Flexor tendon grafts in the fingers and thumb: A study of, factors influencing results in 1000 cases. J Bone Joint Surg Am 53:1332-1342, 1971 8. Boyes J: Flexor tendon grafts in the fingers and thumb: An evaluation of end results, in Hunter JM, Schneider LH, Mackin EJ (eds): Tendon and Nerve Surgery in the Hand. St. Louis, MO, Mosby-Year Book, 1997, pp 410-415 9. Amadio P, Wood M, Cooney W, et al: Staged flexor tendon reconstruction in the fingers and hand. J Hand Surg [Am] 13:559-562, 1988 10. Bishop AT, Topper SM, Bettinger PC: Flexor mechanism reconstruction and rehabilitation, in Peimer C (ed): Surgery of the Hand and Upper Extremity. New York, NY, McGraw-Hill, 1996, pp 1133-1162 11. Strickland J: Flexor tendon injuries, Part 3. Orthop Rev 16:56-64, 1987 12. Mastey RD, Weiss APC, Akelman E: Primary flexor tendon grafting. Atlas Hand Clin 1:121-128, 1996 13. Wehbe M, Hunter J, Schneider L, et ah Two-stage flexor tendon reconstruction. J Bone Joint Surg Am 68:752-763, 1986 14. Schneider L: Staged flexor tendon reconstruction using the method of Hunter. clin Orthop 171:164-171, 1982 15. Sourmelis SG, McGrouther D: Retrieval of the retracted flexor tendon. J Hand Surg [Br] 12B:109-111, 1987 16. Tonkin N, Hagberg L, Lister G, et al: Postoperative management of flexor tendon grafting. J Hand Surg [Br] 13:277-281, 1988 17. Hunter JM, Salisbury RE: Flexor tendon reconstruction in severely damaged hands. J Bone Joint Surg Am 53:829-857, 1971 18. LaSalle W, Strickland J: An evaluation of the two-stage flexor tendon reconstruction technique. J Hand Surg [Am] 8:263-267, 1983 19. Weinstein S, Sprague B, Flatt A: Evaluation of the two-stage flexor tendon reconstruction in severely damaged digits. J Bone Joint Surg Am 58:786-791, 1976 20. Lister G: Pitfalls and complications of flexor tendon surgery. Hand Clin 1:133-146, 1985 21. Parkes A: "Lumbrical plus" finger. Hand 2:164-165, 1970

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