SCIENTIFIC ARTICLE
An Alternative Graft Fixation Technique for Scaphoid Nonunions Treated With Vascular Bone Grafting Anastasios V. Korompilias, MD, Marios G. Lykissas, MD, Ioannis P. Kostas-Agnantis, MD, Ioannis Gkiatas, MD, Alexandros E. Beris, MD
Purpose To present our experience with vascularized bone grafting based on the 1,2intercompartmental supraretinacular artery for the management of established scaphoid nonunion and to investigate the efficacy of graft immobilization with a combination of Kirschner wires and transarticular external fixation. Methods A retrospective chart and radiographic review was conducted for patients with the diagnosis of scaphoid nonunion of the proximal pole or the waist treated with the 1,2-intercompartmental supraretinacular arteryebased vascularized graft and fixed with a combination of Kirschner wires and transarticular external fixation between 2007 and 2011. Results We observed 23 consecutive patients for a mean of 34 4 months. All patients were males with mean age of 25 5 years. All patients had scaphoid nonunion and associated humpback deformity. The mean duration of nonunion was 7 1 months. All scaphoid nonunions united after the index procedure at a mean of 10 1 weeks. Two patients had avascular necrosis of the proximal pole based on the preoperative magnetic resonance imaging findings. After surgery, deformity correction was achieved in all patients, as recorded by the decrease in the lateral intrascaphoid angle and the increase in the dorsal scaphoid angle. At the last follow-up, no patients reported wrist pain. The mean Disabilities of the Arm, Shoulder, and Hand score improved significantly from 32 12 before the operation to 5 3 at the last postoperative visit. All patients showed statistically significant improvement in the range of motion and the grip strength of the involved wrist. Conclusions The results of this study support the combined use of Kirschner wires and transarticular external fixation for fixation of a 1,2-intercompartmental supraretinacular arteryebased vascular bone graft in the treatment of scaphoid nonunions. (J Hand Surg Am. 2014;-:-e-. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Type of study/level of evidence Therapeutic IV. Key words Scaphoid fracture, vascularized bone graft, external fixation, bone healing, scaphoid nonunion.
From the Department of Orthopaedic Surgery, University of Ioannina School of Medicine, Ioannina, Greece. Received for publication December 18, 2013; accepted in revised form April 12, 2014. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Anastasios V. Korompilias, MD, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, PC 45110, Greece; e-mail: koroban1960@gmail. com. 0363-5023/14/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2014.04.021
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60% to 70% of all carpal fractures. In the United States, approximately 345,000 scaphoid fractures occur every year, 5% to 15% of which fail to unite.2 Several methods have been proposed for the management of scaphoid nonunion, taking under consideration the presence of avascular necrosis, collapse, humpback deformity, carpal alignment, and wrist arthrosis. Percutaneous fixation without bone grafting is indicated for nonunions without collapse or CAPHOID FRACTURES CONSTITUTE 1
Ó 2014 ASSH
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Published by Elsevier, Inc. All rights reserved.
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deformity.3 Nonvascularized bone grafting has been proposed for nonunions without proximal pole necrosis. However, a systematic review of the literature showed an average union rate of 78% for proximal pole nonunions treated with nonvascularized bone grafting.4 Vascularized bone grafting has been favored as an alternative for the treatment of proximal pole nonunions and nonunions with proximal pole necrosis, as a primary treatment of established scaphoid nonunion, and after a failed treatment with nonvascularized bone graft, with reported union rates ranging from 27% to 100%.5e13 Vascularized pedicled bone grafting from the distal radius based on the 1,2-intercompartmental supraretinacular artery (1,2 ICSRA) is a promising technique with good results in several studies.5,8,10,13,14 Rigid internal fixation of the 1,2 ICSRA graft with a screw has been shown to have biomechanical advantages over immobilization with Kirschner wires.5,9 However, the presence of a relative large implant in the vascularized graft may increase the possibility of vascular compromise of the graft and preclude the use of postoperative magnetic resonance imaging (MRI) to access the vascularity of the proximal pole and the viability of the graft. We propose an immobilization technique that combines 1 or 2 Kirschner wires and transarticular external fixation. We believe the small-diameter temporary Kirschner wires are advantageous over screw fixation, whereas the wrist external fixator provides additional support. The purposes of this study were to present our experience with 1,2 ICSRA vascularized bone grafting for scaphoid nonunion and to investigate the efficacy of graft immobilization with a combination of Kirschner wires and transarticular external fixation.
nonunion, 23 met the inclusion criteria. Three of the excluded patients were not treated with vascularized bone graft, 3 had previous scaphoid surgery, and 2 had distal pole scaphoid nonunion. The presence of avascular necrosis on MRI was an absolute indication for management with vascularized bone graft. Patients without avascular necrosis but with humpback deformity were also candidates for the procedure. Radiographic evaluation Preoperative radiographic evaluation included posteroanterior, lateral, and scaphoid views of both wrists. In all patients, we applied preoperative CT scan and contrast-enhanced MRI to assess the scaphoid anatomy and osseous blood supply of the proximal pole, respectively. The combination of low signal intensity on T1 images and homogeneous or heterogenous low signal intensity on T2 images of the proximal pole was highly suggestive of avascular necrosis. The absence of intraoperative punctate bleeding was the ultimate test for the diagnosis of avascular necrosis of the proximal pole. Radiographic evaluation with posteroanterior and lateral radiographs was performed immediately after surgery and every 4 weeks thereafter for 12 weeks. Radiographic findings suggesting union included bony bridging at both junction sites of the bone graft and absence of adverse features, such as bony gap or shift of the graft.6,15 We obtained a CT scan to assess bony healing in cases where union was uncertain on plain films. Bone graft healing was diagnosed on CT scans when bony trabeculae bridging both ends of the bone graft to the proximal and distal scaphoid were noted on 2 or more consecutive sequences in either the sagittal or coronal plane.16 We measured the dorsal scaphoid angle and the lateral intrascaphoid angle, defined as the intersection of 2 lines drawn perpendicular to the diameters of the proximal and distal poles, on plain films and CT scans to assess the presence of scaphoid humpback deformity. A dorsal scaphoid angle of 110 or more or a lateral intrascaphoid angle of 35 or more indicated humpback deformity. The height-to-length ratio was also calculated on sagittal views (plain films and CT scans) of the scaphoid to rule out collapse. A ratio greater than 0.65 indicated scaphoid collapse.17
MATERIALS AND METHODS After obtaining institutional review board approval, we retrospectively reviewed the medical records and wrist imaging studies of patients with the diagnosis of scaphoid nonunion observed in our hand clinic between 2007 and 2011. The diagnosis of scaphoid nonunion was established when a clear sclerotic line on both borders of the fracture fragments or cyst formation was evident on plain films or computed tomography (CT) scan 6 months after injury. Inclusion criteria were a minimum follow-up of 2 years, absence of previous scaphoid surgery, scaphoid nonunion of the proximal pole or the waist managed with vascularized bone graft from the distal radius, and postoperative immobilization with a combination of Kirschner wires and transarticular external fixator. Among 31 patients with scaphoid J Hand Surg Am.
Clinical evaluation We recorded flexion and extension and ulnar and radial deviation of both wrists immediately before surgery and at every postoperative visit. All patients were asked to fill out the Disabilities of the Arm, Shoulder, r
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RESULTS We treated 23 consecutive patients with scaphoid nonunion with vascularized bone graft from the distal radius and observed them for a mean of 34 4 months. All patients were males with a mean age of 25 5 years. Seven patients were students, 5 were builders, 5 were athletes, 2 were professional drivers, and 4 were administrative personnel. Scaphoid fracture was the result of sports injury in 15 patients, motor vehicle accident in 6, and fall on an outstretched hand in 2. Four of the 23 patients were smokers. All of them stopped smoking 4 to 6 weeks before surgery and did not resume smoking during the first 6 postoperative months. Nine patients had scaphoid nonunion located at the proximal pole, and 14 had scaphoid waist nonunions. Two patients had avascular necrosis of the proximal pole. The mean duration of nonunion was 7 1 months. All scaphoid nonunions united after the index procedure at a mean of 10 2 weeks. In patients with proximal pole nonunion, union was obtained after a mean time of 11 2 weeks, whereas in patients with waist nonunion, union was recorded after a mean time of 10 1 weeks. These differences were statistically insignificant (P > .05). Five patients had CT scan performed at 12 weeks after the vascularized graft procedure to evaluate fracture healing owing to inconclusive findings on plain films. In all 5 patients, CT scan revealed bone graft healing. After surgery, deformity correction was achieved, as recorded in the decrease in the lateral intrascaphoid angle and the increase in the dorsal scaphoid angle. The mean intrascaphoid angle decreased from 37 2 to 34 4 (P > .05), whereas the mean dorsal scaphoid angle increased from 109 3 to 111 6 (P > .05). Vascularized bone grafting and immobilization with transarticular external fixation resulted in a decrease in the mean height-to-length ratio from 0.67 0.06 before surgery to 0.61 0.04 at the last follow-up (P > .05). One of 2 patients with suspected avascular necrosis of the proximal pole in preoperative MRI had punctate bleeding at the time of surgery. In both patients with suspected avascular necrosis on preoperative MRI, postoperative gadolinium-enhanced MRI at 3 months revealed signs of reperfusion of the proximal pole. At the last follow-up, no patients reported wrist pain. The mean DASH score decreased from 32 12 preoperatively to 5 3 at the last follow-up (P < .001). The mean grip strength increased from 33 9 to 50 8 kg (P < .001).
and Hand (DASH) questionnaire preoperatively and at the time of the last follow-up.18 Grip strength was also measured in both the affected and unaffected extremities using a Jamar dynamometer (J. P. Marsh, Skokie, IL). Two fellowship-trained hand surgeons (A. K. and I. K.-A.) independently evaluated all patients and imaging studies. Operative technique For vascular bone graft harvesting from the dorsoradial distal radius supplied by the 1,2 ICSRA, we used the dorsal approach as described by Shin and Bishop.19 The graft was centered 20 mm proximal to the radiocarpal joint. Before graft elevation, a transverse dorsoradial incision was made in the wrist capsule to expose the scaphoid. Using 2 1.2-mm smooth Kirschner wires inserted into the proximal and distal scaphoid fragment as joysticks, the nonunion site was opened and debrided of fibrous debris and necrotic bone with small curved curettes. At this point, the tourniquet was deflated and avascular necrosis of the proximal pole was confirmed if punctate bleeding was not noticed. The tourniquet was then reinflated for the remainder of the procedure. After the graft was elevated, it was resized and transposed beneath the radial wrist extensors to the nonunion site. Correction of humpback deformity was achieved through a single dorsal approach by harvesting a slightly larger graft that was trimmed and shaped with the wider base volarly. Using 2 Kirschner wires placed in the proximal and distal scaphoid fragment as joysticks, we overdistracted the nonunion site, allowing insertion of the trapezoidshaped bone graft. In all cases, 1 or two 1.2-mm smooth Kirschner wires were inserted into both poles of the scaphoid for graft stabilization, with care taken to avoid injury to the vascular pedicle. The Kirschner wires were left out through the skin. An external fixator (Penning Minifixator, Orthofix, Verona, Italy) spanning the wrist was placed. The external fixator was removed 6 weeks after surgery. The Kirschner wires were removed when union was evident. Statistical analysis We compared preoperative clinical and radiographic scores with follow-up data by paired Wilcoxon tests. Statistical comparison of different groups was performed using the Mann-Whitney U test for nonparametric data. In all instances, P < .05 was regarded as statistically significant. Values are presented as mean SD.
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All patients showed improvement in range of motion of the involved wrist. The mean difference in the postoperative range of motion between the operated and the contralateral normal wrist was 9 63 , 13 6 , 9 6 , and 5 1 in flexion, extension, radial deviation, and ulnar deviation, respectively. These differences were statistically significant (P < .05). One asymptomatic malunion of the vascularized graft was recorded in a patient with waist nonunion. The 2 Kirschner wires used for bone graft fixation were removed 11 weeks after surgery. The height-tolength ratio increased from 0.65 preoperatively to 0.66 at the last follow-up. There were no cases of pin track infection, Kirschner wire loosening or back out, or donor site complications.
removable Kirschner wires has the advantage of enabling an MRI to be performed postoperatively to assess the vascularity of the proximal pole and the viability of the graft, if necessary. External fixation was applied in a neutral wrist position without creating traction or compression forces at the nonunion site. We believe that in the presence of vascularized bone graft, the use of compression screw is not required. Our findings support this notion. The external fixator was well tolerated by all of our patients, especially compared with their previous experience with long and unsuccessful cast application. Limitations of the study include the absence of a comparison group consisting of patients treated with 1,2 ICSRA-based vascular bone grafting fixed with a screw, a factor that may have biased the results. Another limitation was the lack of a postoperative CT scan in all of our patients, which may have overestimated the time to healing and made radiographic measurements inconsistent. A prospective randomized, controlled trial is needed that compares the proposed fixation method with alternative techniques for the treatment of similar scaphoid nonunions.
DISCUSSION In a scaphoid nonunion, pedicled vascularized bone grafting may increase the rate and decrease the time required for achieving bony healing, and may result in revascularization in the setting of avascular necrosis.19 In the present study, union was achieved in 100% of patients treated with vascularized bone graft from the distal radius after an average of 10 weeks. Both the DASH score and patients’ satisfaction showed significant improvement in all patients. No patients reported pain after a minimum 2-year follow-up. Improvement in the range of motion and grip strength was achieved in all patients. Conversely, deformity correction achieved was minimal. The scaphoids described in our study had relatively minimal collapse and were likely stable. Because of the relative small deformity, we did not try to achieve maximal correction, but rather aimed to achieve fusion. Rigid internal fixation with a screw has clear biomechanical advantages over immobilization with 1 or 2 Kirschner wires. In a large study evaluating risk factors for failure after 1,2 ICSRA bone grafting, a higher failure rate was recorded among others when fixation other than screws was used to immobilize the graft.7 More specifically, screw fixation led to union in 23 of 26 nonunions at an average of 15 weeks, whereas Kirschner wire fixation was associated with union in 8 of 15 nonunions at an average of 14 weeks. In the current study, we fixed the vascularized graft with the combination of 1 or 2 Kirschner wires and a transarticular external fixator. Although the fixator was removed 6 weeks after the operation to allow wrist motion exercises, the Kirschner wires were maintained until union occurred. We believe that temporary wrist immobilization with an external fixator provides better support than an orthosis or cast. In addition, the use of J Hand Surg Am.
REFERENCES 1. Simonian PT, Trumble TE. Scaphoid nonunion. J Am Acad Orthop Surg. 1994;2(4):185e191. 2. Kuschner SH, Lane CS, Brien WW, Gellman H. Scaphoid fractures and scaphoid nonunion: diagnosis and treatment. Orthop Rev. 1994;23(11):861e871. 3. Slade JF III, Geissler WB, Gutow AP, Merrell GA. Percutaneous internal fixation of selected scaphoid nonunions with an arthroscopically assisted dorsal approach. J Bone Joint Surg Am. 2003;85(suppl 4): 20e32. 4. 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(5):618e629. 5. Steinmann SP, Bishop AT, Berger RA. Use of the 1,2 intercompartmental supraretinacular artery as a vascularized pedicle bone graft for difficult scaphoid nonunion. J Hand Surg Am. 2002;27(3): 391e401. 6. Boyer MI, von Schroeder HP, Axelrod TS. Scaphoid nonunion with avascular necrosis of the proximal pole: treatment with a vascularized bone graft from the dorsum of the distal radius. J Hand Surg Br. 1998;23(5):686e690. 7. Chang MA, Bishop AT, Moran SL, Shin AY. The outcomes and complications of 1,2-intercompartmental supraretinacular artery pedicled vascularized bone grafting of scaphoid nonunions. J Hand Surg Am. 2006;31(3):387e396. 8. Malizos KN, Dailiana ZH, Kirou M, Vragalas V, Xenakis TA, Soucacos PN. Longstanding nonunions of scaphoid fractures with bone loss: successful reconstruction with vascularized bone grafts. J Hand Surg Br. 2001;26(4):330e334. 9. Straw RG, Davis TR, Dias JJ. Scaphoid nonunion: treatment with a pedicled vascularized bone graft based on the 1,2 intercompartmental supraretinacular branch of the radial artery. J Hand Surg Br. 2002;27(5):413e416. 10. Tsai TT, Chao EK, Tu YK, Chen AC, Lee MS, Ueng SW. Management of scaphoid nonunion with avascular necrosis using 1,2
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11.
12.
13.
14.
15.
intercompartmental supraretinacular arterial bone grafts. Chang Gung Med J. 2002;25(5):321e328. Uerpairojkit C, Leechavengvongs S, Witoonchart K. Primary vascularized distal radius bone graft for nonunion of the scaphoid. J Hand Surg Br. 2000;25(3):266e270. Waters PM, Stewart SL. Surgical treatment of nonunion and avascular necrosis of the proximal part of the scaphoid in adolescents. J Bone Joint Surg Am. 2002;84(6):915e920. Zaidemberg C, Siebert JW, Angrigiani C. A new vascularized bone graft for scaphoid nonunion. J Hand Surg Am. 1991;16(3): 474e478. Waitayawinyu T, McCallister WV, Katolik LI, Schlenker JD, Trumble TE. Outcome after vascularized bone grafting of scaphoid nonunions with avascular necrosis. J Hand Surg Am. 2009;34(3): 387e394. Dias JJ, Taylor M, Thompson J, Brenkel IJ, Gregg PJ. Radiographic signs of union of scaphoid fractures: an analysis of inter-observer
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16.
17.
18.
19.
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agreement and reproducibility. J Bone Joint Surg Br. 1988;70(2): 299e301. Trumble TE, Clarke T, Kreder HJ. Non-union of the scaphoid: treatment with cannulated screws compared with treatment with Herbert screws. J Bone Joint Surg Am. 1996;78(12):1829e1837. Bain GI, Bennett JD, MacDermid JC, Slethaug GP, Richards RS, Roth JH. Measurement of the scaphoid humpback deformity using longitudinal computed tomography: intra- and interobserver variability using various measurement techniques. J Hand Surg Am. 1998;23(1):76e81. Hudak PL, Amadio PC, Bombardier C. Development of an upper extremity outcome measure: the DASH (disabilities of the arm, shoulder and hand) [corrected]. The Upper Extremity Collaborative Group (UECG). Am J Ind Med. 1996;29(6):602e608. Shin AY, Bishop AT. Pedicled vascularized bone grafts for disorders of the carpus: scaphoid nonunion and Kienbock’s disease. J Am Acad Orthop Surg. 2002;10(3):210e216.
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An Alternative Graft Fixation Technique for Scaphoid Nonunions Treated With Vascular Bone Grafting Anastasios V. Korompilias, MD, Marios G. Lykissas, MD, Ioannis P. Kostas-Agnantis, MD, Ioannis Gkiatas, MD, Alexandros E. Beris, MD
Purpose To present our experience with vascularized bone grafting based on the 1,2intercompartmental supraretinacular artery for the management of established scaphoid nonunion and to investigate the efficacy of graft immobilization with a combination of Kirschner wires and transarticular external fixation. Methods A retrospective chart and radiographic review was conducted for patients with the diagnosis of scaphoid nonunion of the proximal pole or the waist treated with the 1,2-intercompartmental supraretinacular arteryebased vascularized graft and fixed with a combination of Kirschner wires and transarticular external fixation between 2007 and 2011. Results We observed 23 consecutive patients for a mean of 34 4 months. All patients were males with mean age of 25 5 years. All patients had scaphoid nonunion and associated humpback deformity. The mean duration of nonunion was 7 1 months. All scaphoid nonunions united after the index procedure at a mean of 10 1 weeks. Two patients had avascular necrosis of the proximal pole based on the preoperative magnetic resonance imaging findings. After surgery, deformity correction was achieved in all patients, as recorded by the decrease in the lateral intrascaphoid angle and the increase in the dorsal scaphoid angle. At the last follow-up, no patients reported wrist pain. The mean Disabilities of the Arm, Shoulder, and Hand score improved significantly from 32 12 before the operation to 5 3 at the last postoperative visit. All patients showed statistically significant improvement in the range of motion and the grip strength of the involved wrist. Conclusions The results of this study support the combined use of Kirschner wires and transarticular external fixation for fixation of a 1,2-intercompartmental supraretinacular arteryebased vascular bone graft in the treatment of scaphoid nonunions. (J Hand Surg Am. 2014;-:-e-. Copyright Ó 2014 by the American Society for Surgery of the Hand. All rights reserved.) Type of study/level of evidence Therapeutic IV. Key words Scaphoid fracture, vascularized bone graft, external fixation, bone healing, scaphoid nonunion.
From the Department of Orthopaedic Surgery, University of Ioannina School of Medicine, Ioannina, Greece. Received for publication December 18, 2013; accepted in revised form April 12, 2014. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Anastasios V. Korompilias, MD, Department of Orthopaedic Surgery, University of Ioannina, Ioannina, PC 45110, Greece; e-mail: koroban1960@gmail. com. 0363-5023/14/---0001$36.00/0 http://dx.doi.org/10.1016/j.jhsa.2014.04.021
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60% to 70% of all carpal fractures. In the United States, approximately 345,000 scaphoid fractures occur every year, 5% to 15% of which fail to unite.2 Several methods have been proposed for the management of scaphoid nonunion, taking under consideration the presence of avascular necrosis, collapse, humpback deformity, carpal alignment, and wrist arthrosis. Percutaneous fixation without bone grafting is indicated for nonunions without collapse or CAPHOID FRACTURES CONSTITUTE 1
Ó 2014 ASSH
r
Published by Elsevier, Inc. All rights reserved.
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deformity.3 Nonvascularized bone grafting has been proposed for nonunions without proximal pole necrosis. However, a systematic review of the literature showed an average union rate of 78% for proximal pole nonunions treated with nonvascularized bone grafting.4 Vascularized bone grafting has been favored as an alternative for the treatment of proximal pole nonunions and nonunions with proximal pole necrosis, as a primary treatment of established scaphoid nonunion, and after a failed treatment with nonvascularized bone graft, with reported union rates ranging from 27% to 100%.5e13 Vascularized pedicled bone grafting from the distal radius based on the 1,2-intercompartmental supraretinacular artery (1,2 ICSRA) is a promising technique with good results in several studies.5,8,10,13,14 Rigid internal fixation of the 1,2 ICSRA graft with a screw has been shown to have biomechanical advantages over immobilization with Kirschner wires.5,9 However, the presence of a relative large implant in the vascularized graft may increase the possibility of vascular compromise of the graft and preclude the use of postoperative magnetic resonance imaging (MRI) to access the vascularity of the proximal pole and the viability of the graft. We propose an immobilization technique that combines 1 or 2 Kirschner wires and transarticular external fixation. We believe the small-diameter temporary Kirschner wires are advantageous over screw fixation, whereas the wrist external fixator provides additional support. The purposes of this study were to present our experience with 1,2 ICSRA vascularized bone grafting for scaphoid nonunion and to investigate the efficacy of graft immobilization with a combination of Kirschner wires and transarticular external fixation.
nonunion, 23 met the inclusion criteria. Three of the excluded patients were not treated with vascularized bone graft, 3 had previous scaphoid surgery, and 2 had distal pole scaphoid nonunion. The presence of avascular necrosis on MRI was an absolute indication for management with vascularized bone graft. Patients without avascular necrosis but with humpback deformity were also candidates for the procedure. Radiographic evaluation Preoperative radiographic evaluation included posteroanterior, lateral, and scaphoid views of both wrists. In all patients, we applied preoperative CT scan and contrast-enhanced MRI to assess the scaphoid anatomy and osseous blood supply of the proximal pole, respectively. The combination of low signal intensity on T1 images and homogeneous or heterogenous low signal intensity on T2 images of the proximal pole was highly suggestive of avascular necrosis. The absence of intraoperative punctate bleeding was the ultimate test for the diagnosis of avascular necrosis of the proximal pole. Radiographic evaluation with posteroanterior and lateral radiographs was performed immediately after surgery and every 4 weeks thereafter for 12 weeks. Radiographic findings suggesting union included bony bridging at both junction sites of the bone graft and absence of adverse features, such as bony gap or shift of the graft.6,15 We obtained a CT scan to assess bony healing in cases where union was uncertain on plain films. Bone graft healing was diagnosed on CT scans when bony trabeculae bridging both ends of the bone graft to the proximal and distal scaphoid were noted on 2 or more consecutive sequences in either the sagittal or coronal plane.16 We measured the dorsal scaphoid angle and the lateral intrascaphoid angle, defined as the intersection of 2 lines drawn perpendicular to the diameters of the proximal and distal poles, on plain films and CT scans to assess the presence of scaphoid humpback deformity. A dorsal scaphoid angle of 110 or more or a lateral intrascaphoid angle of 35 or more indicated humpback deformity. The height-to-length ratio was also calculated on sagittal views (plain films and CT scans) of the scaphoid to rule out collapse. A ratio greater than 0.65 indicated scaphoid collapse.17
MATERIALS AND METHODS After obtaining institutional review board approval, we retrospectively reviewed the medical records and wrist imaging studies of patients with the diagnosis of scaphoid nonunion observed in our hand clinic between 2007 and 2011. The diagnosis of scaphoid nonunion was established when a clear sclerotic line on both borders of the fracture fragments or cyst formation was evident on plain films or computed tomography (CT) scan 6 months after injury. Inclusion criteria were a minimum follow-up of 2 years, absence of previous scaphoid surgery, scaphoid nonunion of the proximal pole or the waist managed with vascularized bone graft from the distal radius, and postoperative immobilization with a combination of Kirschner wires and transarticular external fixator. Among 31 patients with scaphoid J Hand Surg Am.
Clinical evaluation We recorded flexion and extension and ulnar and radial deviation of both wrists immediately before surgery and at every postoperative visit. All patients were asked to fill out the Disabilities of the Arm, Shoulder, r
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RESULTS We treated 23 consecutive patients with scaphoid nonunion with vascularized bone graft from the distal radius and observed them for a mean of 34 4 months. All patients were males with a mean age of 25 5 years. Seven patients were students, 5 were builders, 5 were athletes, 2 were professional drivers, and 4 were administrative personnel. Scaphoid fracture was the result of sports injury in 15 patients, motor vehicle accident in 6, and fall on an outstretched hand in 2. Four of the 23 patients were smokers. All of them stopped smoking 4 to 6 weeks before surgery and did not resume smoking during the first 6 postoperative months. Nine patients had scaphoid nonunion located at the proximal pole, and 14 had scaphoid waist nonunions. Two patients had avascular necrosis of the proximal pole. The mean duration of nonunion was 7 1 months. All scaphoid nonunions united after the index procedure at a mean of 10 2 weeks. In patients with proximal pole nonunion, union was obtained after a mean time of 11 2 weeks, whereas in patients with waist nonunion, union was recorded after a mean time of 10 1 weeks. These differences were statistically insignificant (P > .05). Five patients had CT scan performed at 12 weeks after the vascularized graft procedure to evaluate fracture healing owing to inconclusive findings on plain films. In all 5 patients, CT scan revealed bone graft healing. After surgery, deformity correction was achieved, as recorded in the decrease in the lateral intrascaphoid angle and the increase in the dorsal scaphoid angle. The mean intrascaphoid angle decreased from 37 2 to 34 4 (P > .05), whereas the mean dorsal scaphoid angle increased from 109 3 to 111 6 (P > .05). Vascularized bone grafting and immobilization with transarticular external fixation resulted in a decrease in the mean height-to-length ratio from 0.67 0.06 before surgery to 0.61 0.04 at the last follow-up (P > .05). One of 2 patients with suspected avascular necrosis of the proximal pole in preoperative MRI had punctate bleeding at the time of surgery. In both patients with suspected avascular necrosis on preoperative MRI, postoperative gadolinium-enhanced MRI at 3 months revealed signs of reperfusion of the proximal pole. At the last follow-up, no patients reported wrist pain. The mean DASH score decreased from 32 12 preoperatively to 5 3 at the last follow-up (P < .001). The mean grip strength increased from 33 9 to 50 8 kg (P < .001).
and Hand (DASH) questionnaire preoperatively and at the time of the last follow-up.18 Grip strength was also measured in both the affected and unaffected extremities using a Jamar dynamometer (J. P. Marsh, Skokie, IL). Two fellowship-trained hand surgeons (A. K. and I. K.-A.) independently evaluated all patients and imaging studies. Operative technique For vascular bone graft harvesting from the dorsoradial distal radius supplied by the 1,2 ICSRA, we used the dorsal approach as described by Shin and Bishop.19 The graft was centered 20 mm proximal to the radiocarpal joint. Before graft elevation, a transverse dorsoradial incision was made in the wrist capsule to expose the scaphoid. Using 2 1.2-mm smooth Kirschner wires inserted into the proximal and distal scaphoid fragment as joysticks, the nonunion site was opened and debrided of fibrous debris and necrotic bone with small curved curettes. At this point, the tourniquet was deflated and avascular necrosis of the proximal pole was confirmed if punctate bleeding was not noticed. The tourniquet was then reinflated for the remainder of the procedure. After the graft was elevated, it was resized and transposed beneath the radial wrist extensors to the nonunion site. Correction of humpback deformity was achieved through a single dorsal approach by harvesting a slightly larger graft that was trimmed and shaped with the wider base volarly. Using 2 Kirschner wires placed in the proximal and distal scaphoid fragment as joysticks, we overdistracted the nonunion site, allowing insertion of the trapezoidshaped bone graft. In all cases, 1 or two 1.2-mm smooth Kirschner wires were inserted into both poles of the scaphoid for graft stabilization, with care taken to avoid injury to the vascular pedicle. The Kirschner wires were left out through the skin. An external fixator (Penning Minifixator, Orthofix, Verona, Italy) spanning the wrist was placed. The external fixator was removed 6 weeks after surgery. The Kirschner wires were removed when union was evident. Statistical analysis We compared preoperative clinical and radiographic scores with follow-up data by paired Wilcoxon tests. Statistical comparison of different groups was performed using the Mann-Whitney U test for nonparametric data. In all instances, P < .05 was regarded as statistically significant. Values are presented as mean SD.
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SCAPHOID NONUNION AND VASCULAR BONE GRAFTING
All patients showed improvement in range of motion of the involved wrist. The mean difference in the postoperative range of motion between the operated and the contralateral normal wrist was 9 63 , 13 6 , 9 6 , and 5 1 in flexion, extension, radial deviation, and ulnar deviation, respectively. These differences were statistically significant (P < .05). One asymptomatic malunion of the vascularized graft was recorded in a patient with waist nonunion. The 2 Kirschner wires used for bone graft fixation were removed 11 weeks after surgery. The height-tolength ratio increased from 0.65 preoperatively to 0.66 at the last follow-up. There were no cases of pin track infection, Kirschner wire loosening or back out, or donor site complications.
removable Kirschner wires has the advantage of enabling an MRI to be performed postoperatively to assess the vascularity of the proximal pole and the viability of the graft, if necessary. External fixation was applied in a neutral wrist position without creating traction or compression forces at the nonunion site. We believe that in the presence of vascularized bone graft, the use of compression screw is not required. Our findings support this notion. The external fixator was well tolerated by all of our patients, especially compared with their previous experience with long and unsuccessful cast application. Limitations of the study include the absence of a comparison group consisting of patients treated with 1,2 ICSRA-based vascular bone grafting fixed with a screw, a factor that may have biased the results. Another limitation was the lack of a postoperative CT scan in all of our patients, which may have overestimated the time to healing and made radiographic measurements inconsistent. A prospective randomized, controlled trial is needed that compares the proposed fixation method with alternative techniques for the treatment of similar scaphoid nonunions.
DISCUSSION In a scaphoid nonunion, pedicled vascularized bone grafting may increase the rate and decrease the time required for achieving bony healing, and may result in revascularization in the setting of avascular necrosis.19 In the present study, union was achieved in 100% of patients treated with vascularized bone graft from the distal radius after an average of 10 weeks. Both the DASH score and patients’ satisfaction showed significant improvement in all patients. No patients reported pain after a minimum 2-year follow-up. Improvement in the range of motion and grip strength was achieved in all patients. Conversely, deformity correction achieved was minimal. The scaphoids described in our study had relatively minimal collapse and were likely stable. Because of the relative small deformity, we did not try to achieve maximal correction, but rather aimed to achieve fusion. Rigid internal fixation with a screw has clear biomechanical advantages over immobilization with 1 or 2 Kirschner wires. In a large study evaluating risk factors for failure after 1,2 ICSRA bone grafting, a higher failure rate was recorded among others when fixation other than screws was used to immobilize the graft.7 More specifically, screw fixation led to union in 23 of 26 nonunions at an average of 15 weeks, whereas Kirschner wire fixation was associated with union in 8 of 15 nonunions at an average of 14 weeks. In the current study, we fixed the vascularized graft with the combination of 1 or 2 Kirschner wires and a transarticular external fixator. Although the fixator was removed 6 weeks after the operation to allow wrist motion exercises, the Kirschner wires were maintained until union occurred. We believe that temporary wrist immobilization with an external fixator provides better support than an orthosis or cast. In addition, the use of J Hand Surg Am.
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