89 534 Practical Plastic Surgery Intrinsic Musculature The intrinsic apparatus includes the dorsal interosseus muscles, the volar in- terossei, and the lumbricals. The four dorsal interossei insert onto the proximal phalanges and abduct the fingers and weakly flex the proximal phalanx. The three volar interossei do not attach to bone but rather insert onto the lateral bands that unite with the lateral slips of the extensor tendons. They adduct the fingers and flex the PIP joint. The lumbricals arise from the tendon of FDP on the palmer side and insert onto the radial lateral band of each finger. They primarily extend the IP joints and function as flexors of the MP joints. The intrinsic muscles are innervated primarily by the ulnar nerve, except for the first and second lumbricals, which are innervated by the median nerve. The intricate extensor, flexor and intrinsic systems are interconnected, aligned and stabilized with a system of ligaments found in each finger. The triangular, transverse retinacular and oblique retinacular liga- ments perform a variety of complex actions. The pathology of these ligaments is addressed in the chapter on Dupuytren’s disease. A detailed discussion of their func- tions is listed at the end of this chapter (see Suggested Reading). Blood Supply The extensor tendons are supplied by a number of sources. Vessels from the muscles and bony insertions travel distally and proximally, respectively, down the length of the paratenon. The dorsal aspect of the tendon is not as well vascularized as the deeper surface which receives branches from the periosteum and palmar digi- tal arteries. Unlike the flexor tendons, the extensors have no vincular system. Syn- ovial diffusion plays a major role in the delivery of nutrients, less so than in the flexor tendon system. Figure 89.1. The extensor tendon mechanism. 89 535 Extensor Tendon Injuries Zones of Injury The dorsum of the fingers, hand and wrist can be divided into zones of injury for describing the location of tendon injury (Fig. 89.2). The odd numbered zones over- lie the joints, whereas the even numbered zones overlie the bones. Injuries in zones 2, 3, and 4 of the fingers, and zone 7 in the wrist have a worse prognosis. Extensor tendon lacerations in all zones should be repaired primarily. Little to no tendon retraction occurs in injuries in zones 1-4. Proximal to the MP joints, however, ten- don retraction will occur. Zone 1 and 2 injuries (DIP and middle phalanx) can produce a mallet finger deformity. Zone 3 and 4 injuries (PIP and proximal phalanx) can produce the bou- tonniere deformity. These deformities and their treatment are discussed below. Zone 5 injuries (MP joint) can divide the sagittal band and displace the tendon laterally. The sagittal bands should be repaired. Injuries in this zone will usually cause the tendon stump to retract proximally. Zone 6 injuries of the dorsal hand may not result in loss of extension due to transmission of force from adjacent tendons through the juncturae. In zone 7 injuries of the wrist, the injured retinaculum should be excised, but the proximal or distal portion should be preserved in order to prevent bowstringing of the tendon. Primary Suture Repair Extensor tendons become very thin and flat in the hand, making their repair difficult. They can easily fray during repair. Many suture techniques have been de- scribed for primary repair of extensor tendons. Simple lacerations of the extensor tendon in zone 1 can be repaired with a figure-of-eight stitch. A number of biome- chanical studies support using the Kleinert modification of the Bunnell tech- nique. The modified Kessler technique is also commonly used. The chapter on Figure 89.2. The zones of extensor tendon injury in the fingers and hand. 89 536 Practical Plastic Surgery flexor tendon repair illustrates and discusses these repairs in greater detail. Following primary repair of extensor tendon injuries, the finger should undergo dynamic splint- ing in extension for 4-6 weeks. Partial lacerations of less than 50% can usually be managed by wound care, and splinting for several weeks followed by active motion. Tendon Rupture Rupture of tendons in the nonrheumatoid hand usually occurs 6-8 weeks fol- lowing fractures of the distal radius or carpal bones. Infection and attacks of gout also increase the risk of rupture. Tendons in the nonrheumatoid hand will rupture at the musculotendinous junction or at the bony insertion. Rarely will they rupture within the substance of the tendon itself. The most commonly ruptured tendons are the EPL at Lister’s tubercle, as well as EDM and EDC to the little finger. Tendon ruptures cannot be repaired primarily in most cases, and tendon transfers are re- quired. EPL rupture is usually treated with transfer of the EIP tendon or palmaris longus or interposition autograft. Rupture of the tendons to the little finger can be repaired by suturing the distal stump of the intact tendons of the ring finger. If the extensor muscles have not undergone contracture, tendon grafts are also an option. When performing flexor to extensor transfer, it is important to remember to trans- fer the tendons subcutaneously rather than below the retinaculum since wrist flex- ion occurs in synergy with finger extension. Tendon Loss Loss of segments of an extensor tendon can occur in severe burn, crush, or de- gloving injuries of the dorsum of the hand. Direct primary repair is generally not possible, and tendon transfers or grafts are required. Transfers can be done with both extensor and flexor tendons. A vascularized palmaris longus tendon can be transferred using a pedicled radial forearm fascial flap. A variety of free flaps con- taining vascularized tendons have been described. A composite dorsalis pedis free flap has been used with good results obtained. Staged tendon reconstruction with Hunter rods is also an option. Whatever technique is chosen, immediate recon- struction is preferable to a staged repair. Postoperative Considerations Rehabilitation The traditional approach of static splinting without mobilization has largely been abandoned. Dynamic splinting with controlled motion is now standard of care. Many splints have been described. Most involve splinting the wrist in extension and allow the injured finger to extend passively and partially flex against rubber band resistance. Many studies have shown that early controlled motion decreases the inci- dence of postoperative adhesions and post-traumatic deformities. Proximal injuries (zones 5-7) benefit more from dynamic splinting than distal ones. Children and adults who are unable to cooperate with postoperative hand therapy should un- dergo static splinting. Adhesions Adhesions following lacerations can occur between the tendon and bone, especially if there are underlying fractures. The hallmark is limitation of PIP extension and flexion—due to dorsal tethering. Adhesions should be treated with 6 months of active assisted motion exercises. If this fails, tenolysis may be indicated. Adhesions proximal 89 537 Extensor Tendon Injuries to the MP joint can also be treated with extrinsic extensor release, providing that the intrinsic muscles are intact. In this release, the extrinsic tendon central slip is excised just proximal to the PIP joint. Consequently, the PIP joint will be extended solely by the intrinsic muscles, and the extrinsic tendon will extend only the MP joint. Post-Traumatic Deformities Mallet deformity describes DIP flexion and inability to extend the joint. It results from disruption of the extensor mechanism at the distal phalanx. Injuries can be classified into discontinuity of the extensor tendon (rupture or laceration), avul- sion of the tendon from its distal insertion, or fractures of the distal phalanx. Closed injuries can cause this deformity as a result of forced passive flexion of the DIP joint. If treatment is not pursued, a secondary swan-neck deformity can occur. Treatment consists of continuous immobilization of the DIP in slight hyperextension for 6-8 weeks using a splint or by percutaneous, Kirschner wire fixation. Surgical treatment should be reserved for those who fail conservative management or for fractures re- quiring open reduction. Surgical options include direct tendon repair, tendon graft- ing, arthrodesis, and a number of other reconstructive techniques. Swan-neck deformity describes PIP hyperextension and DIP flexion. It is the pro- gression of a mallet deformity left untreated, as a consequence of disruption of the distal extensor mechanism. The PIP joint progressively extends since all of the force of the extrinsic extensor tendon is transmitted to the PIP joint through the central slip. The DIP joint progressively flexes due to lack of extensor force combined with unop- posed FDP pull on the distal phalanx. With time the volar plate becomes lax at the PIP joint. The swan-neck deformity does not respond well to conservative management, and surgical repair is usually required. Along with repair of the extensor mechanism and any avulsion fractures, the contracted intrinsic muscles and PIP joint collateral ligaments should be released. In addition, the volar plate must also be tightened. Kirschner wires are removed at 4 weeks postoperatively, and a dorsal blocking splint is generally applied at that point. Arthrodesis and arthroplasty are reserved as salvage procedures. Boutonniere deformity describes PIP flexion and DIP/MP hyperextension. It occurs as a result of injury to the central slip over the PIP joint and volar migration of the lateral bands. This deformity is manifest at about 2-6 weeks postinjury, there- fore any trauma to the PIP region should include an evaluation of the extensor tendon. Swelling of the finger can mask a developing Boutonniere deformity. In such cases, the finger should be splinted in extension and examined a few days later after the swelling decreases. Treatment consists of splinting the PIP joint in extension for 6 weeks. The DIP joint should be mobilized during this period to aid in dorsal migration of the lateral bands. Surgical treatment is indicated for avulsions of large bony fragments from the middle phalanx, PIP joint instability and dislocation that cannot be reduced, or extensive soft tissue loss to the dorsum of the finger. The central slip can be recon- structed from the remaining extensor mechanism (e.g., centralizing portions of the lateral bands) or with a tendon graft. Postrepair splinting should be done for 2 weeks. Arthrodesis is indicated for salvage of severely injured fingers. Amputation is occasionally required for severe injuries. Intrinsic-plus contracture describes scarring of the interosseous muscles. This occurs post-traumatically, and can be prevented by minimizing edema of the hand (elevation, ice, NSAIDs, etc), and splinting the hand in the intrinsic-plus (safe) position: MP flexion, IP extension and palmar abduction of the thumb. Intrinsic muscle necrosis and subsequent fibrosis can occur shortly after trauma to the hand. 89 538 Practical Plastic Surgery The finding of pain on passive extension of the MP joints is an early sign of impend- ing intrinsic muscle death. Treatment of intrinsic-plus contracture consists of con- servative splinting first, followed by surgical release when necessary. The interosseous tendons can be severed at the proximal phalanx. If MP flexion contracture is present, however, the release should be performed at the musculotendinous junctions. Post-traumatic adhesions can form between the interossei and the lumbricals distal to the transverse metacarpal ligament. Patients with this condition will present with pain upon fist-making or on forceful finger flexion. These adhesions should be dealt with surgically as soon as they are recognized. Finally, lateral band contractures after trauma can also occur. When present they can impair DIP flexion with passive PIP extension. The involved band should be excised. Pearls and Pitfalls • A patient who presents with a mallet finger (zone I injury), irrespective of the duration of injury, can usually be treated in a closed fashion with splinting alone. This has a high likelihood of success even in cases with a delayed presentation of weeks to months. A stiff finger may require sequential progression of the splint- ing of the DIP joint towards the extended position. • A laceration in the vicinity of the DIP joint is at risk for having entered the joint space. This raises the likelihood of joint infection which can lead to failure of the repair. Delayed tendon repair should be considered in these patients. • Zone III lacerations involving the PIP joint often involve the central slip or lateral bands, and these should be repaired. If the laceration is very close to the insertion of the central slip, there may be insufficient length of distal slip to suture. In this case, a tunnel can be created in the dorsal distal phalanx using a K-wire through which the suture ends can be passed and tied. • Extensor tendon lacerations over the MP joints (zone V) are often due to human bites (either biting or striking an open mouth) whether the patient admits this or not. Such wounds are at very high risk of infection and the tendon should never be repaired primarily. It can be repaired a week later after the wound is no longer contaminated. • Ruptured tendons (most commonly EPL) may present many months to years after injury. In some cases, the muscle belly has atrophied or fibrosed, and ten- don transfer should be performed. Only if there is evidence of a functioning muscle should the tendon be repaired with a tendon graft. Suggested Reading 1. Blair WF, Steyers CM. Extensor tendon injuries. Orthop Clin North Am 1992; 23:141. 2. Browne Jr EZ, Ribik CA. Early dynamic splinting for extensor tendon injuries. J Hand Surg 1989; 14:72. 3. Kleinert HE, Verdan C. Report of the committee on tendon injuries. J Hand Surg 1983; 8:794. 4. Landsmeer JMF. The anatomy of the dorsal aponeurosis of the human finger and its functional significance. Anat Rec 1949; 104:31. 5. Masson JA. Hand IV: Extensor tendons, Dupuytren’s disease, and rheumatoid arthri- tis. Selected Readings Plast Surg 2003; 9(35):1-44. 6. Newport ML, Williams CD. Biomechanical characteristics of extensor tendon suture techniques. J Hand Surg 1992; 17A:1117. 7. Rockwell WB, Butler PN, Byrne BA. Extensor tendon: Anatomy, injury, and recon- struction. Plast Reconstr Surg 2000; 106:1592. 8. Verdan CE. Primary and secondary repair of flexor and extensor tendon injuries. In: Flynn JE, ed. Hand Surgery. 2nd ed. Baltimore: Williams and Wilkins, 1975. Chapter 90 Practical Plastic Surgery, edited by Zol B. Kryger and Mark Sisco. ©2007 Landes Bioscience. Flexor Tendon Injuries Zol B. Kryger and Peter E. Hoepfner Relevant Anatomy Tendons are composed of spiral bundles of Type I collagen, ground substance, elastin, and mature fibroblasts termed tenocytes. Individual collagen bundles are covered by an endotenon. The bundles are organized into fascicles surrounded by a paratenon. The outer layer of the tendon is termed the epitenon. In the distal forearm, the tendons of flexor digitorum superficialis (FDS) are anterior to the tendons of flexor digitorum profundus (FDP). The FDS tendons are arranged in two pairs, with the ring and middle finger tendons lying palmer to the index and little finger tendons. In the hand distal to the carpal tunnel, the tendons of FDS and FDP pair off to the digits, with the FDS lying anterior to the FDP tendon. The tendons of FDS act independently to flex the PIP joints since they arise from single muscle bundles. The tendons of FDP will often act in unison and flex several digits at the DIP joint. This is due to a common muscle origin for several of the tendons, typically the ulnar digits. At the level of the MP joint, the FDS splits into two slips, and the FDP travels through this decussation to now lay anterior. In the digits, the tendons travel in synovial-lined tunnels called flexor tendon sheaths. The sheaths are anchored to the bones by a series of five annular pulleys, numbered A1-A5 from proximal to distal (Fig. 90.1). The odd numbered pulleys are located over the joints; the even pulleys lie over the bones. There are three thin cruciate pulleys, numbered C1-C3, that maintain tendon motion and collapse dur- ing flexion. The palmer aponeurosis lies proximal to the A1 pulley and is often referred to as the A0 pulley. It acts in unison with the first two annular pulleys. Proximal to the entrance into the digital sheath (A1 pulley), the FDS tendon lies palmer to the FDP tendon. At this point, the FDS tendon divides and becomes deep to the FDP tendon. The two portions reunite at Camper’s chiasma and go on Figure 90.1. The digital flexor sheath and its pulley system. The annular pulleys are numbered A1-A5 from proximal to distal, and the cruciate pulleys are num- bered C1-C3. 90 540 Practical Plastic Surgery to attach to the middle phalanx. The FDP tendon, after passing through the FDS bifurcation, attaches to the distal phalanx. Flexor pollicis longus (FPL) is the primary flexor of the thumb. It is the most radial structure in the carpal tunnel. It travels in its own fibrous sheath in the palm and inserts into the base of the distal phalanx of the thumb. The thumb, unlike the fingers, has two annular pulleys, A1 and A2, located over the MP and IP joints, respectively. Lying between them is an oblique pulley that is the most important of the three. Blood Supply The tendons have a rich vascular supply. Longitudinal vessels travel along the dorsal length of the tendons. The paired digital arteries supply segmental vessels to the sheath via the short and long vincula. Finally, the synovial fluid within the ten- don sheath allows oxygen and nutrients to diffuse along its length since there are several short avascular zones over the proximal phalanx. The motion of the tendon facilitates the imbibition that delivers the nutrient-rich synovial fluid. Biomechanics In the neutral wrist position, only 2.5 cm of flexor tendon excursion is needed to produce digital flexion. As the wrist is flexed, the amount of tendon excursion re- quired to flex the digits is more than tripled. Anything that causes the tendon to become flaccid and to bowstring, such as loss of an annular pulley, will result in greater excursion requirements to produce flexion. The A2 and A4 pulleys are the most important in this regard. Loss of either one will result in a substantial reduc- tion in motion and power and a risk of flexion contracture of the digit. Rupture of the pulleys can be diagnosed with clinical exam, ultrasound or MRI. Diagnosis History In obtaining the history, the posture of the hand at the time of injury should be determined. Injuries that occur with the fingers extended will result in the distal end of the tendon being located close to the wound. In contrast, injury to a flexed finger will result in the distal tendon retracting away from the wound as the finger is straightened. Clinical Examination Alterations in the normal resting position should be noted. Separate evaluation of both FDP and FDS function is important. Division of the FDS without injury to the FDP will not be noticeable in the resting posture. However, lacerations on the palmer surface of the fingers will usually sever the FDP tendon before the FDS tendon. FDS is evaluated by immobilizing the surrounding fingers in extension and having the patient flex the finger at the PIP joint. It is critical to isolate each joint since without DIP isolation the common muscle belly to the ulnar FDP digits may generate mock flexion at an adjacent PIP joint. FDS to the index finger is evaluated by having the patient perform a firm pulp-to-pulp pinch with the thumb. An injured FDS will cause as pseudo mallet deformity of the distal phalanx whereas an intact FDS will result in a pseudo boutonniere deformity of the distal phalanx. FDP is evaluated by immobiliz- ing the PIP and IP joints, and evaluating flexion of the isolated DIP joint. A complete sensory exam of the palmar surface is important since trauma to the digital nerves can occur with tendon injuries. Two-point discrimination should be 90 541 Flexor Tendon Repair performed on both the radial and ulnar aspect of each finger. The presence of nerve injury can influence the choice of incision used for exposure. Deep lacerations that disrupt the digital nerves can also sever the digital arteries. The finger can sometimes survive with intact skin even in the presence of bilateral digital artery disruption. However, at least one artery should be repaired if the tendon is also injured in order to avoid ischemia and impaired healing. Indications for Repair Dividing the hand into zones of injury (Zone I-V) is an internationally accepted method of classifying the location of flexor tendon injury (Fig. 90.2). As a general rule, complete flexor tendon lacerations in both the palm and the digital sheath should be repaired. Partial tendon lacerations greater than 60% should be repaired. In the past, zone II was referred to as “no man’s land,” since primary repair resulted in poor functional outcome. However, modern techniques have allowed the repair zone II injuries primarily. Flexor tendon injury is not a surgical emergency; delayed primary repair (up to two weeks post-injury) can provide good long-term results. However, early repair is preferable. Although the early literature recommended against repairing FDS, most surgeons now repair both the FDP and FDS tendons. This is true for all zones of injury. Tendon repair should be attempted after bony fixation and revascularization have been achieved. Nerve repair should also be attempted when feasible. Figure 90.2. The zones of flexor tendon injury in the hand. Zone I is distal to the FDS insertion; zone II is from the A1 pulley to the FDS insertion; zone III is from the carpal tunnel to the A1 pulley; zone IV is the carpal tunnel; zone V is proxi- mal to the carpal tunnel. The thumb is divided into three zones: TI is distal to the IP joint and T2 is distal to the MP joint. 90 542 Practical Plastic Surgery Contraindications to primary tendon repair include: massive soft tissue injuries to the fingers or palm; inadequate skin coverage over the repair; or gross wound contamination. Some surgeons will delay primary repair if the skeletal damage is so severe that postoperative mobilization would not be possible. Operative Technique Since tendon transfers, tendon grafts, and arthrodesis are discussed elsewhere in this book, the focus of this chapter is primary repair. Exposure Rarely can the entire procedure be performed through the site of injury. There are many options for placement of the incision (Fig. 90.3). Lacerations can be extended in appropriate cases. However, if the neurovascular structures need to be explored, greater exposure is necessary. Longer incisions are usually performed in a zigzag fash- ion so that flexion lines in the palm and fingers are not crossed at 90˚ angles in order to avoid scar contracture. The surgeon must consider the position of the hand at the time of injury to determine if the tendon ends are likely to be retracted. Tendon Retrieval To prevent adhesions, atraumatic technique is essential. Tendon ends do not usually require debridement or shortening. It is important to keep the tendons moist throughout the procedure. In Zone I injuries involving the FDP tendon, retrieval is Figure 90.3. Skin incisions for exposure during flexor tendon repair. Whenever possible, the skin laceration should be incorporated into the incision. Flexion lines in the palm and fingers should not be crossed at 90˚. 90 543 Flexor Tendon Repair not usually difficult since the vincula help to anchor the tendon in place. If the DIP joint was flexed at the time of injury, the proximal stump can be retrieved by open- ing the cruciate pulleys (the A4 pulley should be preserved). A suture placed in the tendon can be used to pull it through the A4 pulley. Piercing the tendon transversely with a 25-guage needle can anchor it in place during repair. In zone II injuries, the neurovascular bundles should be identified first. Either the C1 or C2 pulley is opened, whereas the A1-A4 pulleys should be preserved whenever possible. If the proximal stump is close and can be visualized, it should be carefully retrieved. A commonly described technique uses a skin hook to snare the tendon. Occasionally, “milking” the tendon towards the incision is sufficient. If the proximal stump cannot be visualized, the Sourmelis and McGrouther tech- nique is an excellent option. A catheter is passed through the tendon sheath from distal to proximal. The tip of the catheter is exposed via a mid palm incision proxi- mal to the A1 pulley. The catheter is sutured to both tendons and then it is pulled distally, bringing the proximal tendon ends into contact with the distal stumps. It is critical to ensure that the relationship of FDP and FDS at Camper’s chiasma is maintained. Flexing the DIP and PIP joints will help deliver the distal stump of the FDS or FDP tendons. If insufficient distal tendon is exposed, the distal cruciate synovial sheath should be opened. If there is insufficient remaining distal FDP stump, the proximal FDP tendon can be anchored to the base of the distal phalanx. A periosteal flap is elevated and a hole is drilled in the bone. A 3-0 suture is placed in the proximal tendon stump and passed through the bone hole to pull the tendon under the periosteal flap. The suture ends are tied over a piece of cotton and a pad-button placed over the nail. An alternative technique involves the use of bone anchors in the distal phalanx. Suture Technique A variety of suturing techniques have been described (Fig. 90.4). 3-0 or 4-0 braided polyester sutures are best. Locking loops are not necessary and may in fact collapse and Figure 90.4. Representative techniques of end-to-end flexor tendon repair. A) Bunnell repair. B) Kessler grasping repair. C) The original Kessler repair. D) Kessler-Tajima modified repair. E) Interlock repair. F) Double loop repair. [...]... Clin 199 8; 3(2):1 79 2 Chase RA Historical review of skin and soft tissue coverage of the upper extremity Hand Clin 198 5; 1: 599 3 Germann G Principles of flap design for surgery of the hand Atlas Hand Clin 199 8; 3(2):33 4 Gilbert A Pedicle flaps of the upper limb Philadelphia: Lippincott, 199 2 5 Lister G The theory of the transposition flap and its practical application in the hand Clin Plast Surg 198 1;... North Am 199 3; 11:755 6 Rosenthal EA Treatment of fingertip and nail bed injuries Orthop Clin North Am 198 3; 14:675 7 Russell RC, Cases L Management of fingertip injuries Upper Extremity Trauma and Reconstruction 198 9; 94 :1 298 8 Van Beek AL, Kassan MA, Adson MH et al Management of acute fingernail injuries Hand Clin 199 0; 6:23 9 Zook EG Anatomy and physiology of the perionychium Hand Clin 199 0; 6:1 Chapter... for 1-3 weeks 91 Suggested Reading 1 Allen M Conservative management of fingertip injuries in adults The Hand 198 0; 12:257 2 Craig SM Anatomy of the joints of the fingers Hand Clin 199 2; 8: 693 3 Dray GJ, Eaton RG In: Green DP, ed Dislocations and Ligament Injuries in the Digits Operative Hand Surgery 197 8; 3:1 49 4 Fassler PR Fingertip injuries: Evaluation and treatment J Am Acad Orthop Surg 199 6; 4:84... routinely obtained Figure 92 .1 V-Y advancement flap for fingertip amputations The flap can also be volar-based within the fingertip pulp Practical Plastic Surgery, edited by Zol B Kryger and Mark Sisco ©2007 Landes Bioscience 562 Practical Plastic Surgery The bilateral triangular advancement flap, also called the Kutler flap, was classically used for the transverse, or volar-oblique finger tip amputation... performed Suggested Reading 1 Brunner JM The zig-zag volar-digital incision for flexor-tendon surgery Plast Reconstr Surg 196 7; 40:571 2 Idler RS Anatomy and biomechanics of the digital flexor tendons Hand Clin 198 5; 1:3 3 Leffert RD, Weiss C, Athansoulis CA The vincula; with particular reference to their vessels and nerves J Bone Joint Surg 197 4; 56A:1 191 4 Strickland JW Flexor tendon injuries: I Foundations... with forearm island flaps Br J Plast Surg 199 0; 43: 290 7 Weinzweig N, Chen L, Chen ZW The distally based radial forearm fasciocutaneous flap with preservation of the radial artery: An anatomic and clinical approach Plast Reconstr Surg 199 4; 94 :675 8 Zancolli EA, Angrigiani C Posterior interosseous island forearm flap J Hand Surg {Br} 198 8; 13B:130 92 Chapter 93 Carpal Tunnel Syndrome David S Rosenberg... Strickland JW Flexor tendon injuries: I Foundations of treatment J Am Acad Orthop Surg 199 5; 3:44 5 Strickland JW Flexor tendon injuries: II Operative technique J Am Acad Orthop Surg 199 5; 3:55 6 Strickland JW Development of flexor tendon surgery: Twenty-five years of progress J Hand Surg 2000; 25A:214 90 Chapter 91 Injuries of the Finger Millicent Odunze and Gregory A Dumanian Introduction Injuries... The fingertip is the most frequently injured part of the hand, and the middle finger is most vulnerable because it is the most distal and therefore the last to be withdrawn Fingertip injuries are defined as those injuries occurring distal to the Practical Plastic Surgery, edited by Zol B Kryger and Mark Sisco ©2007 Landes Bioscience 548 Practical Plastic Surgery insertion of the flexor and extensor... discussed elsewhere in this book Flaps for Finger Coverage The volar V-Y advancement flap (Fig 92 .1), also called the Atasoy or Kleinert flap, is most commonly used for the dorsal-oblique finger tip amputation with exposed bone The inverted-triangle, V-shaped flap is elevated on the volar pad, and the distal advancement of the wound is closed in Y-fashion With complete division of the fibrous septae and flap... structures are schematically shown in Figure 91 .3 The fingernail is a plate of flattened cells layered together and adherent to one another The nail bed lies immediately deep to the fingernail The nail bed is composed of the germinal matrix, the 91 Figure 91 .3 Sagittal section of the distal finger illustrating the anatomy of the nail and nail bed 552 Practical Plastic Surgery sterile matrix, and the roof . Acad Orthop Surg 199 5; 3:55. 6. Strickland JW. Development of flexor tendon surgery: Twenty-five years of progress. J Hand Surg 2000; 25A:214. Chapter 91 Practical Plastic Surgery, edited by. on Figure 90 .1. The digital flexor sheath and its pulley system. The annular pulleys are numbered A1-A5 from proximal to distal, and the cruciate pulleys are num- bered C1-C3. 90 540 Practical Plastic. described (Fig. 90 .4). 3-0 or 4-0 braided polyester sutures are best. Locking loops are not necessary and may in fact collapse and Figure 90 .4. Representative techniques of end-to-end flexor tendon