Reconstruction of flexor tendon with hunter tendon implant

Reconstruction of flexor tendon with hunter tendon implant

RECONSTRUCTION OF FLEXOR TENDON WITH HUNTER TENDON IMPLANT RANDALL W. CULP, MD, FAGS Reconstruction of a scarred flexor tendon system with a single-s...

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RECONSTRUCTION OF FLEXOR TENDON WITH HUNTER TENDON IMPLANT RANDALL W. CULP, MD, FAGS

Reconstruction of a scarred flexor tendon system with a single-stage tendon graft can result in failure. Staged restoration involving implantation of a flexible silicone prosthesis at the first stage can be the best reconstructive option for severely damaged digits. To achieve optimal results, careful patient selection and surgical technique is essential. KEY WORDS: flexor tendon, reconstruction, silicon implant

Restoration of flexor tendon function in a badly scarred digit has historically been difficult. Reconstruction with a single-stage tendon graft has yielded inconsistent recovery. 1"2 To improve the flexor bed in which tendon grafts are placed, a staged reconstruction using a flexible silicone prosthesis in the first stage has been popularized by Hunter et al. 3-7 This technique converts a severely scarred tendon bed to a smooth, well-organized pseudosheath through which a tendon can glide. Numerous reports have n o w documented the usefulness of this technique in otherwise difficult or unsalvageable digits.6,8 -10

SURGICAL INDICATIONS AND CONTRAINDICATIONS Staged flexor tendon reconstruction is a salvage procedure. It is used for injuries that are too severe for primary repair or one-stage tendon grafting. 11 Patients must be made aware of the complexity of the problem and the need for lengthy postoperative therapy. In some cases, arthrodesis or amputation may be more appropriate. Patients with severe chronic neurovascular impairment are generally poor candidates. 12 Indications include: 1. 2. 3. 4. 5.

Severe initial injury. Scarred flexor tendon bed. Loss of retinacular pulley system. Scarred profundus bed with intact superficialis. Replantation. Contraindications include:

1. Acute infection (absolute). 2. Borderline vascularity (relative). From the Hand Rehabilitation Center, Ltd, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA. Address reprint requests to Randall W. Gulp, MD, FACS, Associate Professor of Orthopedic Surgery, Jefferson Medical College of Thomas Jefferson University, Hand Rehabilitation Center, Ltd, 901 Walnut St, Philadelphia, PA 19107. Copyright 9 1993 by W. B. Saunders Company 1048-6666/93/0304-0007505.00/0

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93. Bilateral digital nerve injuries. 4. Severe joint stiffness.

TECHNIQUE Stage I The flexor digital sheath is exposed through a volar zigzag (Brunner) incision extending proximally into the palm. This allows complete exposure of the tendon bed. The digital neurovascular bundles are identified and protected. If a midlateral incision was previously used, a volar approach can still be used. All undamaged segments of the fibro-osseous pulley system are spared. Scarred tendons are carefully excised through transverse windows in the flexor sheath. Distally, a generous segment of profundus tendon (at least 1 cm) is preserved. The A5 pulley is usually sacrificed to perform this adequately. The superficialis is transected proximal to the vincula breve, if possible, to prevent later hyperextension of the proximal interphalangeal joint. The distal aspect of the superficialis also can be used for later sheath reconstruction. All excised tendon material is set aside in a moist sponge for possible use and pulley reconstruction. The proximal profundus is transected just distal to the lumbrical origin. If the lumbrical is scarred, it is excised to prevent later "lumbrical plus" finger. After tendon excision, if joint flexion contractures are not corrected, volar plate and accessory collateral ligament releases may be performed. The contracted finger may require shifting or advancement of local skin flaps. The V to Y is an effective method to release skin tension. Severe contractures with skin loss may require local flaps with skin grafts. When the palm was not involved in the original or subsequent surgeries, some surgeons prefer to carry the staged tendon from the tip of the digit to the palm so no further incisions are required. However, most surgeons prefer to implant the silicone rod from the tip to the distal forearm. In this case, a second curvilinear incision is made above the wrist in the ulnar one half of the volar aspect of the forearm. The ulnar artery, nerve, and median nerve are identified and protected. The involved

Operative Techniques in Orthopaedics, Vol 3, No 4 (October), 1993: pp 298-302

proximal superficialis tendon is drawn into the w o u n d and transected near the musculotendinous junction. A trial set of passive Hunter Tendon implants (Phoenix BioMedical Corporation, Bridgeport, PA) may be useful to determine appropriate size. A 4-mm implant is frequently appropriate because it closely corresponds to the size of the expected tendon graft. The trial implant is threaded through the remaining pulleys and free gliding should be demonstrated. At this point, deficiencies in the annular pulley system must be assessed and corrected by pulley reconstruction.

RETINACULAR PULLEY RECONSTRUCTION The basic anatomy of the flexor pulley system permits maximal arc of motion. This precise biomechanical design must be restored at stage I surgery. A minimal requirement is the presence of A2 and A4 pulleys at the proximal and middle phalangeal levels, respectively. Restoration of a four-pulley system may insure the best functional recovery: one proximal to each of the three finger joints and one at the base of the proximal phalanx. 11-13 Tendon material that is to be discarded or dorsal retinaculum (Lister) serve as biological material for pulley reconstruction. Several techniques are available (Fig 1). The circumferential method of Bunnell is currently favored. 11"12 Incisions are made adjacent to the proximal or middle phalanges. Graft material is passed around the phalanx beneath the extensor tendon at the proximal phalangeal level and over it at the middle phalangeal

level. A ligature carrier may be used to perform the graft or in particularly difficult cases, a second additional dorsal incision. Following trimming of excess tendon, the suture line is rotated either laterally or dorsally. Because 6 to 8 cm of graft is required to encircle the phalanx one time, additional tendon material such as palmarls longus may be required. At the A2 level, the phalanx is usually encircled twice to insure a larger area for force transmission. Reconstructed pulleys must hold the implant as close to the bone as possible without restricting its gliding. Other methods of pulley reconstruction include use of the tail of the superficialis to reconstruct pulleys in the A3, distal A2, or proximal A4 area. It is left at its insertion and the free end is sutured over the implant to the contralateral periosteum or rim of original pulley. Tendon grafts can also be interwoven through the retained rim of a previous pulley (Kleinert). 14 Finally, slits produced in the palmar plate can act as pulley (Karev). is When immediate postoperative digital motion is required, pulleys may be protected using circumferential orthoplast plastic rings or taping. If necessary, injured nerves are prepared for later repair at this stage. The actual tendon implant is now removed from its sterile package and placed in the retinacular system in a distal to proximal direction (Fig 2). If the implant is to be placed in the distal forearm, the plane behveen the profundus and superficialis is used with the help of a tendon passer. The distal implant juncture is performed. There are currently two techniques available. The first technique

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Fig 1. Techniques of retinacular pulley reconstruction. FLEXOR TENDON RECONSTRUCTION WITH IMPLANT

Fig 2. Tendon implant after retinacular pulley reconstruction. 299

Fig 7. Stage II proximal juncture using Pulvertaft weave.

Fig 5. Stage II proximal and distal incisions.

Fig 6. Stage il distal juncture.

tendon. A fish-mouth closure finally embraces the graft. Postoperatively, a protective dorsal splint is applied keeping the wrist in 30 ~ of flexion, the MP joints at 70 ~ of flexion, and the interphalangeal joints in full extension. Presently, these patients are managed with early controlled mobilization via an elastic band attached to the finger (Fig 8). The patient is instructed to extend actively the finger to the limits of the splint and to relax FLEXOR TENDON RECONSTRUCTION WITH IMPLANT

Fig 8. Postoperative controlled mobilization.

reciprocally as the elastic band flexes the finger. This is repeated 10 times per hour. In addition, gentle passive flexion of each interphalangeal joint is performed 10 times twice a day. Early attention is paid to flexion contractures. Gentle passive extension of the contracted joint may begin as early as I week by careful flexion of the 301

adjacent joints. Gentle active m o t i o n is allowed at 3 to 4 weeks. T h e b u t t o n is r e m o v e d at 4 weeks. Additional protection can be p r o v i d e d for several weeks w i t h a wrist cuff and r u b b e r band. Blocking exercises are u s e d at 6 weeks. Because of the salvage n a t u r e of the p r o c e d u r e a n d the severe effect that r u p t u r e w o u l d h a v e on o u t c o m e , some s u r g e o n s feel immobilization for 3 to 4 w e e k s followed b y active flexion a n d blocking is m o r e appropriate p o s t o p e r ative care. 13

RESULTS The usefulness of this technique was d o c u m e n t e d in a n initial r e p o r t b y H u n t e r and Salisbury in 1971. 6 Further s u p p o r t of the technique as the best reconstructive option for severely d a m a g e d digits came from a r e p o r t f r o m LaSalle and Strickiand. 9 T h e y n o t e d excellent or g o o d results in 39% of the digits, w h i c h i m p r o v e d to 65% following tenolysis that was required in 47% of their patients. A follow-up s t u d y by W e h b e , et al 1~ d e m o n s t r a t e d in 150 digits a total active m o t i o n of 176 ~ a n d a m e a n grip strength of 79% c o m p a r e d to a preoperative 102 ~ and 20%. Complications i n c l u d e d varying degrees of flexion contracture in 41% of digits, r u p t u r e of the t e n d o n graft in 14%, a n d infection in 4%. Amadio, et al 8 d e m o n s t r a t e d 54% excellent or g o o d results in 130 digits. Sixteen percent of patients required tenolysis. C o m p l i c a t i o n s i n c l u d e d infection in 15%, r u p t u r e in 4%, a n d a m p u t a t i o n in 4%. Factors associated with p o o r results in their s t u d y included injury in z o n e s 1 a n d 2 in patients w h o are less t h a n 10 years of age.

CONCLUSION T h e use of a passive t e n d o n implant in a two-stage technique has p r o v e d to be a reliable technique for salvaging d a m a g e d flexor t e n d o n systems. Patient selection and strict a d h e r e n c e to b o t h surgical technique a n d postoper-

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ative s u p e r v i s e d t h e r a p y are the keys to maximize final digit function.

REFERENCES 1. Butler B, Burkhalter WE, Cranston JP: Flexor tendon grafts in the severely scarred digit. An experimental study in dogs. J Bone Joint Surg [Am] 50:452457, 1968 2. McCormack RM, Demuth RJ, Kindling PH: Flexor tendon grafts in the less-than-optimum situation. J Bone Joint Surg [Am] 44:13601364, 1962 3. Hunter JM: Artificial tendons. Early development and applications. Am J Surg 109:325-338, 1965 4. Hunter JM: Staged flexor tendon reconstructing, in Hunter JM, Schneider LH, Mackin El, et al (eds): Rehabilitation of the Hand (ed 2). St Louis, MO, Mosby, 1984, pp 288-313 5. Hunter JM, Salisbury RE: Use of gliding artificial implants to produce tendon sheaths. Techniques and results in children. Plast Reconstr Surg 45:564-572, 1970 6. Hunter JM, Salisbury RE: Flexor tendon reconstruction in severely damaged hands: A two-staged procedure using a silicone-dacron reinforced gliding prosthesis prior to tendon grafting. J Bone Joint Surg [Am] 53:829-858, 1971 7. Hunter JM, Schneider LH: Staged flexor tendon reconstruction: Current status, in American Academy of Orthopaedic Surgeons Symposium in Tendon Surgery in the Hand. St Louis, MO, Mosby, 1975, 271-274 8. Amadio PC, Wood MB, Cooney WP, et ah Staged flexor tendon reconstruction in the fingers and hand. J Hand Surg [Am] 13:559562, 1988 9. LaSalle WB, Strickland JW: An evaluation of the two-stage flexor tendon reconstruction technique. J Hand Surg [Am] 8:263-267, 1983 10. Wehbe MA, Hunter JM, Schneider LH, et ah Two-stage flexortendon reconstruction. J Bone Joint Surg [Am] 68:752-763, 1986 li. Imbriglia JE, Hunter JM, Rennie WV: Secondary flexor tendon reconstruction. Hand Clin 5:395-413, 1989 12. Schneider LH, Hunter JM: Flexor tendons---Late reconstruction, in Green DP (ed): Operative Hand Surgery (ed 2). New York, NY, Churchill Livingstone, 1988, pp 1969-2044 13. Stfickland JW: Flexor tendon surgery. Part 2: Free tendon grafts and tenolysis. J Hand Surg [Br] 14:368-382, 1989 14. Kieinert HE, Bennett JB: Digital pulley reconstruction employing the always present rim of the previous pulley. J Hand Surg [Am] 3:297-298, 1978 15. Karen A: The "belt loop" technique for the reconstruction of pulleys in the first stage of flexor tendon grafting, l Hand Surg [Am] 9:923924, 1984

RANDALL W. CULP

THE SUPERFICIALIS FINGER PROCEDURE WILLIAM H. KIRKPATRICK, MD, and RAYMOND J. KOBUS, MD

Severe flexor tendon injuries and failed tendon graft procedures may require a compromise of the standard principles of restoration of a three-joint, two-tendon flexor system. The superficialis finger procedure is an option in flexor tendon surgery to restore motion to the proximal interphalangeal joint by tendon graft or recession of the profundus tendon to the middle phalanx, with arthrodesis or tenodesis of the distal interphalangeal joint. KEY WORDS: superficlalis finger, salvage, tendon grafting

Restoration of a functional finger following failed primary flexor tendon repair or flexor tendon grafting continues to be a challenge to surgeons treating hand injuries. In some cases of severe damage to the finger involving tendon, pulley, bone, nerve, and vascular injury, the goals of restoration of a three-joint, two-tendon flexor system may require a compromise for the benefit of hand function. Conversion to a superficialis finger is such a compromise in that attention is directed to restoration of proximal interphalangeal (PIP) joint motion at the sacrifice of distal interphalangeal (DIP) joint motion, establishing a two-joint, one-tendon flexor system. Indications for this "redemption operation ''1'2 include the following: (1) failure of tendon grafting as a result of an incompetent pulley system or rupture of the graft insertion in the distal phalanx; (2) flexor tendon disruption with an inadequate DIP joint caused by arthrosis or irreparable extensor tendon damage or insufficiency; (3) multiple prior failed procedures on the flexor tendon system.

the proximal one third of the middle phalanx with a drill bit or bone awl with small curettes. The w i n d o w should be of sufficient diameter to accept the distal aspect of the tendon graft. One or two Keith needles are then inserted with or without power into the palmar window and through the dorsal cortex, angulating distally to

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TECHNIQUE The principles of staged flexor tendon reconstruction have been previously discussed in this journal and must be closely followed. The distal attachment of the tendon graft is at the level of the middle phalanx or into the middle phalanx, rather than into the distal phalanx. This juncture can be made into bone or by suturing the tendon graft to a remaining 1-cm segment of the original superficialis insertion into the middle phalanx or to a portion of pulley overlying the middle phalanx. A tendon-to-bone distal juncture is more commonly used. The distal end of the tendon graft is secured with a 3-0 or 4-0 nonabsorbable pull-out suture or wire using the Bunnell suture technique. Care is taken to protect the remaining or reconstructed pulleys, in particular the A2 pulley. A unicortical window is then fashioned in From the Department of Orthopaedic Surgery, The Bryn Mawr Hospital, Bryn Mawr, PA, and Thomas Jefferson University, Philadelphia, PA; and the Department of Orthopaedic Surgery, Ohio State University Hospital, Columbus, OH. Address reprint requests to William H. Kirkpatrick, MD, Hand Surgical Associates, 830 Old Lancaster Rd, Suites 300-301, Bryn Mawr, PA 19010. Copyright 9 1993 by W. B. Saunders Company 1048-6666/93/0304-0008505.00/0

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Fig 1. A single Keith needle has been inserted through a unicortical window in the proximal third of the middle phalanx of the index finger. A nonabsorbable suture has been woven through the distal end of the tendon graft and then into the eye of the Keith needle. The DIP joint has been arthrodesed with Kirschner wire fixation.

Operative Techniques in Orthopaedics, Vol 3, No 4 (October), 1993: pp 303-305

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