Several conditions in the wrist involve

Review Article Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction Alexander Payatakes, MD Dean G. Sotereanos, MD Abstract Conventional bone grafts have some osteogenic potential, whereas vascularized bone grafts retain live, functional osteocytes and osteoblasts. High rates of scaphoid union have been achieved with conventional bone grafting in the absence of osteonecrosis or prior surgery. Vascularized bone grafting is valuable in the management of wrist disorders with compromised bone vascularity (eg, scaphoid nonunion with proximal pole necrosis, Preiser disease, Kienböck disease) or when previous grafting has failed. Improved understanding of the vascular anatomy of the wrist has allowed the use of an array of vascularized bone grafts that do not require microsurgical anastomosis. Successful outcome depends on careful patient selection and appropriate surgical technique. Dr. Payatakes is Assistant Professor, Penn State Milton S. Hershey Medical Center, Bone and Joint Institute, Hershey, PA. Dr. Sotereanos is Vice-chairman, Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA. Neither of the following authors nor a member of their immediate families has received anything of value from or owns stock in a commercial company or institution related directly or indirectly to the subject of this article: Dr. Payatakes and Dr. Sotereanos. Reprint requests: Dr. Payatakes, Bone and Joint Institute, 30 Hope Drive, EC089, Hershey, PA 17033. J Am Acad Orthop Surg 2009;17: 744-755 Copyright 2009 by the American Academy of Orthopaedic Surgeons. Several conditions in the wrist involve vascular compromise of carpal bones (eg, proximal scaphoid fractures, Kienböck disease, Preiser disease). These conditions lead to biologic and mechanical deterioration of the involved bone, with subsequent carpal destabilization and early degenerative articular changes. Vascularized Bone Grafts Conventional bone grafts have long been used in the management of carpal disorders to improve bone healing and restore normal osseous anatomy. Nonvascularized bone graft, however, possesses limited osteogenic potential and must eventually be replaced with live bone by creeping apposition from the periphery. Osteoclastic resorption may cause significant mechanical weakening during this prolonged process. Suboptimal results with conventional bone grafts led to the use of vascularized bone grafts, which have the theoretic advantage of preservation of live osteocytes and osteoblasts. 1 Several animal models and clinical studies have demonstrated the superior biologic and mechanical properties of vascularized bone grafts. 2-7 Perfusion of vascularized bone grafts not only is maintained but also substantially increases over time. 5 Animal models have shown that vascularized bone grafts are incorporated in a faster, more predictable manner, especially when placed in a poorly vascularized bed. 1,6-8 In contrast to the process of creeping apposition, vascularized grafts have been shown to undergo repopulation by live host osteocytes in a rapid and diffuse manner. 8 Clinical Application in the Wrist Clinical applications of vascularized bone grafts in the wrist have included treatment of scaphoid non- 744 Journal of the American Academy of Orthopaedic Surgeons

Alexander Payatakes, MD, and Dean G. Sotereanos, MD unions, Preiser disease, Kienböck disease, and failed arthrodeses. The first report of the use of a vascularized bone graft in the wrist was by Roy-Camille, 9 who transferred the scaphoid tubercle on an abductor pollicis brevis muscle pedicle. Since then, several experimental studies have led to increased understanding of the vascular anatomy of the wrist and demonstrated a fairly consistent pattern of adequately sized vessels. 10,11 This has led to the description and use of several vascularized bone grafts from the distal radius, 10,12-17 ulna, 18 and metacarpals. 19,20 Successful use of free vascularized bone grafts has also been reported. 21-23 Pedicled vascularized bone grafts in common use for the management of scaphoid nonunions, Preiser disease, and Kienböck disease have specific indications and limitations (Table 1). Scaphoid Nonunion Indications The current consensus on indications for vascularized bone grafting includes scaphoid nonunion with proximal pole osteonecrosis and/or failure of previous grafting. 2,3 Use of vascularized bone grafting for acute scaphoid fractures with a small proximal fragment has been suggested; however, this indication has not gained wide acceptance. 11 Selection of a specific graft type depends on the characteristics of the nonunion and the presence or absence of significant deformity, which dictate the surgical approach. Most scaphoid fractures can be successfully treated nonsurgically or with fixation and conventional bone grafting. Tenuous blood supply and significant torque forces, however, result in an overall nonunion rate of 5% to 15% despite treatment. 24,25 Risk factors include displacement >1 Table 1 Vascularized Bone Graft Recommendations Based on Pathology Indication Scaphoid proximal third nonunion Proximal pole osteonecrosis (minimal deformity) Scaphoid waist nonunion Humpback deformity (significant) mm, proximal fracture location, delayed treatment, inadequate immobilization, associated carpal instability, and osteonecrosis. 26 Osteonecrosis develops in approximately 3% of all scaphoid fractures, with a significantly higher risk in proximal third fractures. 25 Proximal pole hypovascularity is determined by radiographic sclerosis, characteristic changes on MRI, and intraoperative absence of punctate bleeding. 27 Reported scaphoid union rates with use of conventional nonvascularized bone graft range from 60% to 90%, dropping to 40% to 67% when proximal pole osteonecrosis is present. 16,25,28 Several studies report the use of vascularized bone grafts for treatment of scaphoid nonunions with union rates >90%. 29-32 Union rates remain high in revision cases and in the presence of impaired vascularity of the proximal pole. 16,32 Critical evaluation of available studies is difficult because of diverse inclusion criteria (ie, presence or absence of deformity), methods for assessment of union and vascularity, Recommended Graft Alternatives Comments 1,2 ICSRA Capsule-based Volar radius VBG (radial carpal artery) 2,3 ICSRA Index DMCA Free VBG Free VBG (iliac crest, femoral condyle) Preiser disease 1,2 ICSRA 2,3 ICSRA Index DMCA Capsule-based Kienböck disease (Herbert stages II, IIIA) 4+5ECA Pisiform 2,3 ICSRA Index DMCA Capsule-based surgical techniques, and outcome measures. Two recent meta-analyses have compared treatment methods for scaphoid nonunions. 2,3 Merrell et al 2 examined 36 eligible studies and found an overall union rate of 88% with vascularized bone grafts in patients with scaphoid nonunion and proximal pole necrosis, compared with 47% with the use of conventional grafts (P < 0.0005). Munk and Larsen 3 reported that use of vascularized bone grafting led to a union rate of 91% in patients with prior failed surgery and/or proximal pole necrosis, compared with a previously reported 64% union rate with use of conventional grafts in this population, and an overall union rate of 80% to 84% with conventional grafting. Other reported results, however, have been significantly less encouraging. 23,25,33,34 Regardless of the approach and type of graft used in surgery, fibrous tis- ± Unloading Poor prognosis (type I) ± Unloading 1,2 ICSRA = first and second intercompartmental supraretinacular artery, 2,3 ICSRA = second and third intercompartmental supraretinacular artery, 4 + 5 ECA = fourth and fifth extensor compartmental artery, DMCA = dorsal metacarpal artery, VBG = vascularized bone graft December 2009, Vol 17, No 12 745

Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction Figure 1 Illustrations of surgical technique for 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) graft by the dorsal approach. A, Dorsal serpentine incision (dark line). The pedicle (dashed line) is identified superficial to the retinaculum between the first and second extensor compartments and dissected distally to its anastomosis with the radial artery. B, Preparation of a trough across the nonunion site and elevation of vascularized graft. C, The bone graft is transferred to the graft site. (Adapted with permission from the Mayo Foundation for Medical Education and Research, Rochester, MN.) sue and necrotic bone should be meticulously excised. Implant selection depends on surgeon preference, fragment size, and stability. Headless compression screws have been associated with significantly higher union rates and are preferable when technically feasible. 2,25 Noncannulated mini-screws or Kirschner wires (Kwires) may be used when small proximal fragment size precludes use of a cannulated screw. Hardware placement should allow for subsequent placement of the graft. Harvesting technique varies according to the type of graft. Adequate graft fixation can typically be achieved with a press-fit technique. Additional stability can be provided by a K-wire or bone anchor placed in the recipient trough. Large wedge grafts should be stabilized with the compression screw fixation, when possible. Postoperatively, the extremity is immobilized in a sugar tong splint for 2 weeks followed by a short-arm thumb spica cast for another 4 weeks. Radiographs are obtained with cast removal at 6 weeks and, if necessary, monthly thereafter to assess for union. CT may be necessary to demonstrate osseous bridging of the fracture site. Return to full activities is permitted only after solid union is demonstrated. Proximal Third Nonunion Without Significant Deformity Proximal third nonunions without significant humpback deformity are typically managed through a dorsal approach. The most advantageous grafts are those based on the 1,2 or 2,3 intercompartmental supraretinacular artery (ICSRA) or the fourth extensor compartmental artery within the dorsal wrist capsule (capsule-based graft). 1,2 ICSRA Graft The 1,2 ICSRA originates from the radial artery 5 cm proximal to the radiocarpal joint, courses beneath the brachioradialis, and emerges onto the dorsal surface of the retinaculum, finally anastomosing with the radial artery or radiocarpal arch within the anatomic snuffbox (Figure 1, A). The procedure is performed with loupe magnification under tourniquet control after simple extremity elevation to facilitate identification and dissection of the vascular pedicle. The 1,2 ICSRA is identified on the surface of the retinaculum and dissected distally to the radial artery 12 (Figure 1, A). A retinacular cuff (the 1,2 intercompartmental septum) containing nutrient arteries to bone is created. Before elevation 746 Journal of the American Academy of Orthopaedic Surgeons

Alexander Payatakes, MD, and Dean G. Sotereanos, MD Table 2 Reported Results With the Use of Vascularized Bone Grafts in Wrist Surgery Indication Study Osteonecrosis Vascularized Bone Graft Union Time to Union (weeks)/ Comments Scaphoid nonunion Scaphoid nonunion (waist//humpback deformity) Zaidemberg US 1,2 ICSRA 11/11 6.2 et al 12 Uerpairojkit et al 29 5/10 1,2 ICSRA 10/10 6.5 Tsai et al 31 US 1,2 ICSRA 5/5 <18 Malizos et al 30 * 7/22 1,2 ICSRA 22/22 6-12 Steinmann et al 26 4/14 1,2 ICSRA 14/14 11.1 Boyer et al 33 10/10 1,2 ICSRA 6/10 18.4 Strawetal 34 16/22 1,2 ICSRA 6/22 (ON, 2/16) US Chang et al 25 24/48 1,2 ICSRA 34/48 15.6/Broad indications Waitayawinyu 30/30 1,2 ICSRA 28/30 21.9 et al 32 * Sotereanos et al 17 10/13 Capsule-based 10/13 (ON, 8/10) 6-12 Mathoulin et al 19 US Index DMCA 14/15 17.3 Yuceturk et al 20 4/4 Index DMCA 4/4 9.1 Doi et al 21 10/10 Free (distal femur) 10/10 12 Jones et al 23 12/12 Free (distal femur) 12/12 12 Harpf et al 22 26/60 Free (iliac crest) 55/60 (ON, 24/26) US/Donor site morbidity Merrell et al 2 Various ON, 88% US (meta-analysis) Kuhlmann et al 13 US Volar radius 3/3 US Mathoulin and US Volar radius 17/17 8.6 Haerle 14 Dailiana et al 16 1/9 Volar radius 9/9 9 Preiser disease Kalainov et al 37 Various/± ULP 0/4 NRP Type I/FU = 33 mo Kalainov et al 37 Various/± ULP 2/5 NRP Type II/FU = 21 mo Moran et al 36 Various/± ULP 5/8 NRP, 8/8 RV Type I/FU = 36 mo Kienböck disease Moran et al 15 4 + 5 ECA/± ULP 20/26 NRP, 12/17 RV FU = 31 mo Daecke et al 38 Pisiform/± ULP 14/22 NRP, 6/22 RV FU = 12 y Daecke et al 39 Saffar procedure 9/17 NRP, 10/20 RV FU = 10 y * None of the patients used tobacco at the time of surgery. All patients had carpal collapse. 1,2 ICSRA = first and second intercompartmental supraretinacular artery, 4 + 5 ECA = fourth and fifth extensor compartmental artery, DMCA = dorsal metacarpal artery, FU = follow-up, NRP = no radiographic progression, ON = osteonecrosis, RV = revascularization, ULP = unloading procedure, US = unspecified, VBG = vascularized bone graft of the graft, the scaphoid is exposed through a transverse capsulotomy (Figure 1, B). Scaphoid hardware should be placed relatively volar to allow for placement of the graft in a dorsal trough across the nonunion site. The graft is appropriately outlined around the pedicle with the distal edge approximately 1.5 cm proximal to the radiocarpal joint. The graft is elevated with a distally based pedicle, after which it is contoured and transferred to the prepared trough, with or without additional fixation (Figure 1, C). Graft perfusion may be verified by releasing the tourniquet before graft insertion. Outcomes Zaidemberg et al 12 reported union after a mean of 6.2 weeks in 11 of 11 scaphoid nonunions treated with a 1,2 ICSRA graft (Table 2). Results of treatment of nonunions with proximal pole necrosis have not been uniform. Uerpairojkit et al 29 used the 1,2 ICSRA graft to treat 10 patients December 2009, Vol 17, No 12 747

Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction with scaphoid nonunion, 5 of whom had documented proximal pole necrosis; they achieved union in all 10 patients at a mean of 6.5 weeks. Malizos and colleagues 30,35 reported union within 6 to 12 weeks in 22 of 22 patients with proximal nonunions, including 7 of 7 with documented osteonecrosis. Waitayawinyu et al 32 reported union after a mean of 21.9 weeks in 28 of 30 patients with proximal pole necrosis. No patient had undergone prior surgery, and none was using tobacco at the time of surgery. Less favorable outcomes were achieved by Boyer et al, 33 who reported union in 6 of 10 patients with nonunion and proximal pole necrosis. Most vascularized bone grafting studies included in the meta-analysis by Merrell et al 2 used the 1,2 ICSRA. An overall union rate of 88% was reported in patients with scaphoid nonunion and proximal pole necrosis. The largest series to date had an overall union rate of 71% (34/48 patients); only 12 of 24 patients with proximal pole necrosis achieved union. 25 The authors attributed this to a broadening of their indications after promising early results. Closer observation reveals that 10 of the 14 total failed cases (with or without proximal pole necrosis) in fact had humpback deformity, collapse, or carpal instability, which should be considered relative contraindications for dorsal vascularized grafting. The authors concluded that this patient group would best be served with an alternative procedure. 23,25 Union was achieved in 12 of 15 patients with nonunion and proximal pole necrosis and none of the above-mentioned complicating factors. More recently, Straw et al 34 reported union in only 2 of 16 scaphoid nonunions with associated necrosis. This may partially be attributed to surgical technique because many failures were fixed with only one K-wire, which was removed at 8 weeks regardless of radiographic evidence of union. Advantages and Limitations Despite a short arc of rotation, the 1,2 ICSRA graft is ideally located for transfer to the proximal pole of the scaphoid. The main disadvantage, as with all dorsally harvested grafts, rests in the inability to correct clinically significant humpback deformity. The course and characteristics of the vascular pedicle make it vulnerable to kinking and impingement, occasionally necessitating a styloidectomy. 36 Capsule-based Vascularized Graft In an attempt to simplify pedicle dissection and minimize the risk of vessel kinking, Sotereanos et al 17 developed a vascularized bone graft that is harvested from the dorsal distal radius and is attached to a distally based strip of wrist capsule. This graft is technically straightforward and may be transferred to the scaphoid or lunate with minimal rotation. Latex-injection studies of wrist vascular anatomy demonstrated reliable vascularization of this bone graft by the fourth extensor compartmental artery (4 ECA). 10 This vessel is always present, with a mean diameter of approximately 0.4 mm. It runs along the floor of the fourth compartment radial to the posterior interosseous nerve (70% of cases) or within the 3,4 intercompartmental septum (30%), provides numerous nutrient arteries, and anastomoses distally with the dorsal intercarpal arch, the dorsal radiocarpal arch, and other compartmental arteries (Figure 2, A). The capsulebased vascularized bone graft may therefore be viewed as an axial flap (based on 4 ECA) and is harvested with the ease of a random flap. The procedure may be performed under tourniquet control because no vascular pedicle dissection is necessary. The third and fourth compartments are released, exposing the wrist capsule and distal radius. The capsule-based vascularized graft is designed as a 1 cm 1 cm bone block slightly ulnar and distal to Lister s tubercle, including the 3,4 intercompartmental septum 17 (Figure 2, B). The bone block is harvested approximately 7 mm deep and includes the dorsal ridge of the radius, attached to a capsular flap that widens from 1 cm proximally to 1.5 cm at its distal base. The graft is elevated with a thin osteotome, maintaining 2 to 3 mm of distal radius cortex intact to prevent propagation into the joint. The capsular flap is outlined sharply with a scalpel, with care taken to preserve the scapholunate ligament. Release of the tourniquet allows evaluation of both proximal pole and graft perfusion. The capsular flap typically demonstrates abundant vascularity; punctate bleeding from the bone graft may lag. The graft is rotated slightly and placed in a dorsal trough across the nonunion site, with or without additional fixation (headless compression screw, K-wire or bone anchor) (Figure 2, C). Outcomes Sotereanos et al 17 reported excellent results with use of this vascularized bone graft for management of 13 scaphoid nonunions, all of which involved the proximal third and 10 of which were complicated by proximal pole necrosis (documented by radiographic findings, MRI, and/or intraoperative evaluation). Radiographic union was achieved within 3 months 748 Journal of the American Academy of Orthopaedic Surgeons

Alexander Payatakes, MD, and Dean G. Sotereanos, MD Figure 2 Illustrations of a capsule-based vascularized bone graft artery by the dorsal approach. A, Vascular anatomy of the dorsal wrist. Note the location of the fourth extensor compartmental artery (4 ECA) within the fourth compartment or 3,4 intercompartmental septum. B, Design of the bone graft and distally based capsular flap containing the distal extension of 4 ECA. C, Transfer of the bone graft to the graft site with minimal rotation of the capsular flap. (Adapted with permission from Sotereanos DG, Darlis NA, Dailiana ZH, Sarris IK, Malizos KN: A capsular-based vascularized distal radius graft for proximal pole scaphoid pseudarthrosis. J Hand Surg Am 2006;31:580-587.) in 10 of 13 patients (76.9%), with similar union rates noted within the osteonecrosis group (8/10). All 10 healed patients reported minimal or no pain at follow-up (mean, 19 months; minimum, 12 months) and had an increase in range of motion and grip strength. No donor site morbidity was noted. Violation of the dorsal extrinsic ligaments did not result in clinical or radiographic instability. Advantages and Limitations The main advantage of the capsulebased vascularized graft is the simple harvesting technique, which obviates the need for meticulous pedicle dissection. The convenient position of the capsule-based graft allows easy access to both the proximal scaphoid pole and the lunate, with a short arc of rotation and low risk of nutrient vessel kinking. As with the 1,2 ICSRA, this graft cannot correct clinically significant humpback deformity. Vascularity of the graft is unreliable in patients with previous surgery or significant injury to the dorsal aspect of the wrist. The theoretic disadvantage of violation of the dorsal radiocarpal and intercarpal ligament has not been shown to result in carpal instability in patients without prior evidence of scapholunate dissociation. 17 Two patients with mild static scapholunate instability did not develop more significant instability after harvesting of this graft. 17 Waist Nonunion and Humpback Deformity Nonunion at the scaphoid waist or the presence of significant humpback deformity make the volar approach preferable for surgical management. The previously described vascularized bone grafts from the dorsal radius are less advantageous in this patient population. Vascularized options for this clinical scenario include pedicled bone grafts from the volar distal radius and free vascularized bone grafts from the iliac crest or the medial femoral condyle. 13,21-23 The volar radius vascularized graft obviates the need for microvascular anastomosis and allows harvesting of sufficient bone to correct humpback deformity. Volar Radius Vascularized Graft Use of a vascularized bone graft from the volar aspect of the distal radius was first reported by Kuhlmann et al 13 and further described by Mathoulin December 2009, Vol 17, No 12 749

Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction Figure 3 Illustrations of the volar approach to volar radius vascularized bone grafting. A, This graft is based on the radial carpal artery (the radial contribution to the palmar carpal arch), located just distal to the pronator quadratus. The pedicle (dashed outline) is elevated as a fascioperiosteal flap 4 to 5 mm wide to prevent vessel kinking. B, Bone graft is transferred to the graft site. A volar approach facilitates correction of humpback deformity. (Adapted with permission from Mathoulin C, Haerle M: Vascularized bone graft from the palmar carpal artery for treatment of scaphoid nonunion. J Hand Surg Br 1998;23:318-323.) and Haerle. 14 Dailiana et al 16 stressed the importance of elevating the pedicle as a 5-mm fascioperiosteal strip containing the nutrient artery, thus simplifying dissection and creating a more resilient pedicle. The volar distal radius bone graft is based on the radial carpal artery, the radial contribution to the palmar carpal arch (Figure 3, A). This arch is located just distal to the pronator quadratus and is consistently supplied by the radial carpal artery and the anterior branch of the anterior interosseous artery, typically with additional contribution from the ulnar artery. The radial carpal artery has a diameter of 0.5 to 1 mm and gives off several periosteal and cortical perforating branches. 13 The procedure is performed with loupe magnification under tourniquet control (after simple extremity elevation). A typical volar approach is extended proximally, with care taken to protect the radial carpal artery. The nonunion site is débrided, and the need for humpback deformity correction is noted because it dictates graft configuration and dimensions according to principles described by Fernandez. 40 The palmar carpal arch is visualized by transversely incising the pronator quadratus aponeurosis 1 cm proximal to its distal edge and retracting the muscle belly proximally. The vascular pedicle is subperiosteally elevated off the radius within a fascioperiosteal cuff, with dissection toward the radial artery performed as required to obtain the necessary arc of motion. A graft measuring 1 cm 3 is elevated with a thin osteotome from ulnar to radial, with care taken not to propagate the osteotomy into the radiocarpal or distal radioulnar joint. The graft is appropriately configured and placed within or across the nonunion site with rotation of the pedicle (Figure 3, B). Fixation of the graft is achieved either by the headless compression screw or by an additional, temporary, volarly placed K-wire. Outcomes Kuhlmann et al 13 reported union in all three patients treated with use of the volar radius vascularized graft. Mathoulin and Haerle 14 used this technique to manage 17 waist nonunions, 10 of which had failed previous surgery. All 17 patients healed after a mean of 8.6 weeks (range, 6 to 12 weeks). Results were rated as excellent or good in 12 of 17 cases. Dailiana et al 16 reported their results in nine nonsmokers with waist nonunions, one of whom had preoperative evidence of proximal pole necrosis. Union was achieved in all 9 patients after a mean of 9 weeks (range, 6 to 12 weeks). Graft vascularity and incorporation was verified by MRI in 6 of 9 cases. Clinical outcome was rated as excellent in five cases; good results were obtained in the other four cases. Advantages and Limitations Graft harvesting from the volar surface of the distal radius allows fixation and vascularized bone grafting of waist nonunions through a single volar approach and preserves dorsal blood supply to the scaphoid. The main advantage of the volar vascularized graft is the option to simultaneously correct humpback deformity 750 Journal of the American Academy of Orthopaedic Surgeons

Alexander Payatakes, MD, and Dean G. Sotereanos, MD by using an appropriately configured graft. Its proponents further suggest that use of this graft may preserve wrist flexion compared with dorsal grafting, although this, to our knowledge, has not been substantiated. 16 Prior surgery through a volar approach and significant trauma in this area constitute relative contraindications for this technique. The surgeon must be prepared to use a dorsal radius or free graft if the radial carpal artery is compromised. Preiser Disease Preiser disease involves osteonecrosis of the scaphoid without known prior injury. Treatment options include observation, arthroscopic débridement, proximal row carpectomy, and scaphoid excision with midcarpal fusion. 36 Silicone replacement causes synovitis and is no longer recommended. 41 Herbert and Lanzetta 42 proposed a staging system based on the absence of radiographic sclerosis (stage I), presence of sclerosis (stage II), fragmentation (stage III), and collapse (stage IV), with or without arthritic changes. Kalainov et al 37 have distinguished two types of disease: type I represents generalized scaphoid necrosis, whereas type II disease represents segmental necrosis and may be the result of unrecognized trauma. Type II disease has been shown to progress more slowly and to have a better prognosis. There have been limited reports of attempts at scaphoid salvage with use of vascularized bone grafts in patients with early Preiser disease. Both 1,2 ICSRA and 2,3 ICSRA grafts have been used. A prerequisite for any salvage attempt is the presence of an intact articular cartilaginous shell and the absence of significant arthritic changes at the radiocarpal and midcarpal joints. In surgery, the scaphoid cartilaginous shell is evaluated intraoperatively, and the feasibility of salvage with vascularized bone grafting is determined. A power burr and curet are used to remove as much of the necrotic and sclerotic bone as possible through a dorsal cortical window. Care is taken to avoid violation of the cartilaginous shell. The vascularized bone graft is harvested from the dorsal distal radius, as described, placed in the developed trough, and fixed with K-wires for 6 to 8 weeks. Unloading of the radioscaphoid joint by scaphocapitate pinning or bridging external fixation is recommended. Radial styloidectomy is performed as necessary to prevent impingement of the vascular pedicle or to address early radioscaphoid degenerative changes. 36 Outcomes Kalainov et al 37 first reported their results in a series of patients with stage II Preiser disease treated with various types of vascularized bone grafting. All four patients with Kalainov type I disease demonstrated radiographic progression. Three of four scaphoids were salvaged at 33 months follow-up; one patient underwent a wrist fusion. Patients with type II disease fared better, with radiographic progression in two of five patients at 21 months follow-up. The scaphoid was salvaged until latest follow-up in all five cases. Moran et al 36 treated eight patients with generalized (type I) disease with vascularized bone grafting. Three patients had stage II and five patients had stage III disease preoperatively. The 1,2 ICSRA graft was used in six cases; two patients received a 2,3 ICSRA graft. Additional unloading of the joint was performed in five patients. At 36 months, MRI demonstrated partial revascularization in all patients, although residual necrosis was evident in the proximal pole. Pain was reduced, and grip strength was slightly increased. Mild loss of motion resulted, and radiographic progression (dorsal intercalated segmental instability deformity and/or arthritic changes) was noted in three of eight patients. Stage I Preiser disease is a more difficult clinical scenario than posttraumatic nonunion with osteonecrosis. The entire scaphoid is involved, and progression without treatment is rapid. 37 The technical difficulty of adequately removing necrotic bone without violating the cartilaginous shell, combined with poor results, has led some authors to consider Preiser disease a contraindication for vascularized bone grafting. 25 Others feel that these poor results still compare favorably to other available management options for early (Herbert stage I or II) disease. 37 More advanced disease is an indication for scaphoid excision/midcarpal fusion, proximal row carpectomy, or total wrist arthrodesis. Kienböck Disease Kienböck disease consists of idiopathic lunate osteonecrosis, which some investigators have attributed to osseous and vascular anatomic variations that place the lunate blood supply at risk to trauma (acute or repetitive). Lunate osteonecrosis may lead to fragmentation, collapse, and subsequent radiocarpal/midcarpal arthritis. Treatment depends on disease stage, ulnar variance, and the condition of the lunate cartilaginous shell. Options include immobilization, unloading procedures (eg, radial shortening/wedge osteotomy, capitate shortening), revascularization (vascularized bone grafts, arteriovenous pedicles), lunate excision/ replacement, and salvage procedures December 2009, Vol 17, No 12 751

Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction Figure 4 Illustrations of the surgical technique for a fourth and fifth extensor compartmental artery (4 + 5 ECA) graft. A, The 5 ECA is identified and followed proximally to the palmar branch of the anterior interosseous artery (paia). This branch is ligated proximal to its bifurcation, and the 4 ECA is then followed distally. The bone graft is outlined on the ulnar aspect of the distal radius around the 4 ECA. B, The vascularized bone graft is then elevated and transferred to the prepared lunate. Care is taken to preserve the cartilaginous shell of the lunate bone. Unloading of the lunate for 6 to 8 weeks by scaphocapitate pinning or external fixation is recommended. (Adapted with permission from the Mayo Foundation for Medical Education and Research, Rochester, MN.) for advanced disease (intercarpal arthrodesis, proximal row carpectomy, total wrist arthrodesis). Revascularization may be indicated for Lichtman stage II disease (precollapse) and possibly stage IIIA disease (collapse without scaphoid rotation). Lunate collapse with fixed scaphoid rotation (Lichtman stage IIIB disease) and the presence of degenerative changes in the radiocarpal and/or midcarpal joint (Lichtman stage IV disease) require proximal row carpectomy, limited wrist arthrodesis, or total wrist arthrodesis. Revascularization with direct vascular pedicle implantation has been described; however, most authors recommend use of a vascularized bone graft (ie, pedicled pisiform, pronator quadratus muscle bone flap, or dorsal distal radius bone grafts). The vascularized bone graft most commonly used for treatment of Kienböck disease is based on the fourth and fifth extensor compartmental arteries (4 + 5 ECA) 15 (Figure 4, A). It is based on retrograde flow from the fifth ECA, which then courses orthograde into the fourth ECA. Two recent long-term studies have also renewed interest in vascularized pisiform transfer. 38,39 4 + 5 ECA Graft The 4 + 5 ECA graft procedure is performed with loupe magnification under tourniquet control (after simple extremity elevation). The fifth compartmental artery (5 ECA) is identified adjacent to or partially within the 4,5 intercompartmental septum and traced proximally to the palmar branch of the anterior interosseous artery, which is ligated. The 4 ECA is followed distally along the floor of the fourth extensor compartment radial to the posterior interosseous nerve or within the 3,4 intercompartmental septum (Figure 4, A). The lunate is exposed through a ligament-respecting capsulotomy, and the cartilage shell is evaluated. A power burr and curet are used to remove the necrotic bone through a dorsal cortical window. The graft is elevated around the 4 ECA (centered 1 cm proximal to the radiocarpal joint) and placed into the lunate with a press-fit technique. The lunate is typically unloaded with scaphocapitate pinning or external fixation for 6 to 12 weeks. If no external fixator is placed, then postoperative splinting and casting is necessary for a minimum of 6 to 8 weeks. Advantages and Limitations The harvest site and the location of the pedicle make the 4 + 5ECAgraft ideal for use in Kienböck disease. Arthrotomy is performed without risk of injury to the vessel. Although greater pedicle length would allow this graft to reach the proximal scaphoid, the 1,2 ICSRA and capsule-based grafts are typically preferred for proximal scaphoid nonunions because of their proximity. Vascularized Pisiform Transfer of a pedicled pisiform for lunate revascularization was first described by Beck 43 and modified by Kuhlmann et al. 44 Saffar 45 later proposed resection of the collapsed lunate and replacement by the vascularized pisiform, which has been shown to have similar height to the intact lunate. A typical carpal tunnel approach is extended proximally over the flexor carpi ulnaris muscle. The flexor retinaculum and volar capsule are incised to expose the lunate. Care is taken to preserve the extrinsic liga- 752 Journal of the American Academy of Orthopaedic Surgeons

Alexander Payatakes, MD, and Dean G. Sotereanos, MD ments and the cartilaginous shell. The lunate is cored out for grafting. The pisiform is dissected from the flexor carpi ulnaris, the hypothenar muscles, and the pisotriquetral capsule, with preservation of the dorsal branch of the ulnar artery on its ulnar border (Figure 5). The pedicle is dissected from distal to proximal. The pisiform is transferred to the lunate after its articular surface and part of its cortex are rongeured. The volar capsuloligamentous structures are repaired. Radial shortening may be additionally performed in patients with negative ulnar variance. The lunate/pisiform may also be temporarily unloaded with scaphocapitate pinning or external fixation. For advanced disease, the lunate bone may be excised for replacement. The intact pisiform is then transferred on its vascular pedicle and inserted with its articular surface toward the capitate. Advantages and Limitations The location of the pisiform makes it an attractive source of vascularized bone for the lunate. Lunate replacement restores carpal height and may reduce scaphoid flexion, but it does not reconstruct the proximal articular surface and intrinsic ligaments. The ulnar nerve is at risk during pisiform harvesting, with incomplete ulnar nerve injury reported in 4 of 21 patients in one study. 39 Outcomes Moran et al 15 treated 26 patients with Kienböck disease, using the 4 + 5 ECA vascularized graft. Twelve had stage II disease, 10 had stage IIIA, and 4 had degenerative changes (stage IV). Temporary unloading was performed in 20 patients (77%). Radiographic stabilization of the disease was achieved in 77% of patients. Pain was significantly reduced in 92%, and grip strength improved from 50% to 89% compared with Figure 5 Illustrations of a vascularized pisiform transfer. A, Vascular supply to the pisiform. The dorsal branch of the ulnar artery provides nutrient vessels on the ulnar aspect of the pisiform. B, The pisiform is excised from the flexor carpi ulnaris muscle and transferred on a dorsal branch of the ulnar artery as vascularized graft to the lunate bone. The flexor carpi ulnaris is sutured to the capsule of the triquetrum. the contralateral side. Range of motion was not significantly improved. Revascularization of the lunate was noted in 12 of 17 patients evaluated by MRI. Outcome was found to correlate with revascularization. Daecke et al 38 reported satisfactory long-term results with pedicled pisiform grafting in a series of 23 patients with stage II/IIIA disease. Eleven had additional radial shortening osteotomies. At 12-year followup, no progression was noted in 14 of the 23. Revascularization was noted in six patients and was associated with positive clinical outcome. Range of motion was significantly increased, and grip strength was 84% of the contralateral side. Pain was significantly reduced in 20 of the patients. No difference was noted in patients who underwent an additional radial shortening procedure. Comparison of these results with the natural history of the disease is difficult, and no studies have directly compared these techniques with unloading procedures or intercarpal fusions. Quenzer et al 46 reported radiographic improvement in 55% of patients who underwent vascularized grafting in addition to an unloading procedure, compared with only 20% after unloading procedures alone. A long-term study of unloading procedures showed results similar to those of vascular bone grafting; however, at a mean follow-up of 14.5 years, significant arthritis was present in 73% of patients 47 compared with 36% of patients who underwent additional vascularized bone grafting. 38 Some authors have postulated that lunate unloading may indirectly promote revascularization; however, Weiss et al 48 found evidence of revascularization in only one third of patients treated by unloading procedure alone. Vascularized bone grafting therefore is an attractive op- December 2009, Vol 17, No 12 753

Pedicled Vascularized Bone Grafts for Scaphoid and Lunate Reconstruction tion for early Kienböck disease (Lichtman stages II and IIIA). It may be performed as an isolated procedure for patients with neutral or positive ulnar variance or as an adjunct to unloading procedures in the patients with negative ulnar variance. Daecke et al 39 also reported results of lunate replacement by vascularized pisiform (ie, Saffar procedure) for advanced Kienböck disease (Lichtman stages IIIA, IIIB, and IV). At 10-year follow-up, they noted halted disease progression in 9 of 17 patients and reduced scaphoid flexion in 7 of 17 patients. The pisiform maintained its height in 13 cases and had normal trabecular structure in 10. Motion did not change significantly, and grip strength was 79% that of the contralateral side. Pain was significantly reduced in 18 of 21 patients. Long-term results with the Saffar procedure appear to be comparable to those of other salvage procedures for advanced stages of Kienböck disease. 49 Complications The primary complications of vascularized bone grafting of the carpal bones (scaphoid, lunate) are persistent nonunion and collapse. Chang et al 25 evaluated 50 patients treated for scaphoid nonunion to identify risk factors for failure. Proximal pole necrosis, preoperative humpback deformity, and unstable (nonscrew) fixation were found to correlate with failure (P 0.01). Tobacco use and older age also significantly reduced the union rate (P < 0.05). These risk factors appeared to have a cumulative effect. Union rates for waist and proximal fractures were comparable when vascularity was normal. Another common complication is graft extrusion, which occurred in 8.3% of cases in one large series; one half of these cases healed in the extruded position. 25 Infection and loss of motion have been reported. All patients should be informed preoperatively of the possible need for additional surgery (ie, revision fixation/ grafting, proximal row carpectomy, partial or total wrist arthrodesis). Summary Conventional bone grafting still has a place in wrist surgery and achieves scaphoid union rates comparable to those of vascularized grafting in the absence of osteonecrosis or prior surgery. Vascularized bone grafting is a useful option for the management of wrist disorders in which bone vascularity is compromised (eg, scaphoid nonunion with proximal pole osteonecrosis, Kienböck or Preiser disease) or when previous grafting has failed. Its use for acute treatment of proximal scaphoid fractures is controversial. An array of local vascularized grafts has been described recently. Successful outcome depends on careful patient selection and appropriate surgical technique. Patients with substantial humpback deformity should be considered for vascularized volar radius grafts. Patients with generalized Preiser disease may benefit from vascularized grafting but have a suboptimal prognosis. Vascularized bone grafting provides a reliable treatment option for ulnarneutral/positive patients with earlystage Kienböck disease and a useful adjunct to unloading procedures for ulnar-negative patients. Prospective comparative studies are needed to further delineate the indications for vascularized grafting procedures in the wrist. References Evidence-based Medicine: Levels of evidence are described in the table of contents. In this article, references 1 and 5-8 are level II studies. References 2-4, 11, 23, 27, and 40 are level III studies. References 10, 12-22, 25, 26, 29-37, 39, 41, 42, and 44-49 are level IV studies. References 9, 24, 28, 37, and 43 are level V expert opinion. Citation numbers printed in bold type indicate references published within the past 5 years. 1. Dell PC, Burchardt H, Glowczewskie FP Jr: A roentgenographic, biomechanical, and histological evaluation of vascularized and non-vascularized segmental fibular canine autografts. J Bone Joint Surg Am 1985;67:105-112. 2. Merrell GA, Wolfe SW, Slade JF III: Treatment of scaphoid nonunions: Quantitative meta-analysis of the literature. J Hand Surg Am 2002;27:685-691. 3. Munk B, Larsen CF: Bone grafting the scaphoid nonunion: A systematic review of 147 publications including 5,246 cases of scaphoid nonunion. Acta Orthop Scand 2004;75:618-629. 4. Plakseychuk AY, Kim SY, Park BC, Varitimidis SE, Rubash HE, Sotereanos DG: Vascularized compared with nonvascularized fibular grafting for the treatment of osteonecrosis of the femoral head. J Bone Joint Surg Am 2003;85: 589-596. 5. Tu YK, Bishop AT, Kato T, Adams ML, Wood MB: Experimental carpal reverseflow pedicle vascularized bone grafts: Part II. Bone blood flow measurement by radioactive-labeled microspheres in a canine model. J Hand Surg Am 2000;25: 46-54. 6. Shaffer JW, Field GA, Goldberg VM, Davy DT: Fate of vascularized and nonvascularized autografts. Clin Orthop Relat Res 1985;197:32-43. 7. Sunagawa T, Bishop AT, Muramatsu K: Role of conventional and vascularized bone grafts in scaphoid nonunion with osteonecrosis: A canine experimental study. J Hand Surg Am 2000;25:849-859. 8. Muramatsu K, Bishop AT: Cell repopulation in vascularized bone grafts. J Orthop Res 2002;20:772-778. 9. Roy-Camille R: Fractures and pseudoarthroses of the scaphoid waist: Use of a pedicled graft [French]. Actual Chir Ortho R Poincare 1965;4:197-214. 10. Sheetz KK, Bishop AT, Berger RA: The arterial blood supply of the distal radius and ulna and its potential use in vascularized pedicled bone grafts. J Hand Surg Am 1995;20:902-914. 754 Journal of the American Academy of Orthopaedic Surgeons

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