Treatment of Scaphoid Waist Nonunions with an Avascular Proximal Pole and Carpal Collapse Surgical Technique

Transcription

1 169 Copyright 2009 by The Journal of Bone and Joint Surgery, Incorporated Treatment of Scaphoid Waist Nonunions with an Avascular Proximal Pole and Carpal Collapse Surgical Technique By David B. Jones Jr., MD, Heinz Bürger, MD, Allen T. Bishop, MD, and Alexander Y. Shin, MD Investigation performed at the Mayo Clinic, Rochester, Minnesota, and Landeskrankenhaus Klagenfurt, Klagenfurt, Austria The original scientific article in which the surgical technique was presented was published in JBJS Vol. 90-A, pp , December 2008 ABSTRACT FROM THE ORIGINAL ARTICLE BACKGROUND: Surgically, it is difficult to achieve union of a scaphoid nonunion that is associated with osteonecrosis of the proximal pole, and those with carpal collapse are especially difficult to treat. A variety of vascularized bone grafts can be used. The purpose of this study was to compare the effectiveness of two types of vascularized bone graft a distal radial pedicle graft and a free vascularized medial femoral condyle graft in the treatment of scaphoid waist nonunions associated with proximal pole osteonecrosis and carpal collapse. METHODS: A retrospective review was conducted at two institutions to identify all patients with a scaphoid waist nonunion associated with an avascular proximal pole and carpal collapse. Between January 1994 and June 2006, twenty-two such nonunions were identified in twenty-two patients. Ten were treated with a distal radial pedicle vascularized graft and twelve, with a free vascularized medial femoral condyle graft. Patient demographics were similar between the groups, and the duration of follow-up averaged twelve months. Union was determined with use of plain radiographs and computed tomography or trispiral tomograms. In addition, carpal angles, time to union, union rates, and complications were recorded. RESULTS: Four of the ten nonunions treated with the distal radial pedicle graft healed, at a median of nineteen weeks, and all twelve nonunions treated with the free medial femoral condyle graft healed, at a median of thirteen weeks. The rate of union was significantly higher (p = 0.005) and the median time to healing was significantly shorter (p < 0.001) for the nonunions treated with the medial femoral condyle graft. CONCLUSIONS: A vascularized interposition graft from the medial femoral condyle is the recommended vascularized bone graft for the surgical treatment of scaphoid waist nonunion with avascularity of the proximal pole and carpal collapse. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: Treatment of Scaphoid Waist Nonunions with an Avascular Proximal Pole and Carpal Collapse. A Comparison of Two Vascularized Bone Grafts (2008;90: ). DISCLOSURE: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. J Bone Joint Surg Am. 2009;91 Suppl 2 (Part 2): doi: /jbjs.i.00444

2 170 INTRODUCTION Scaphoid nonunions associated with osteonecrosis of the proximal pole and a humpback deformity have proven difficult to treat, given the need to restore both vascular supply as well as scaphoid length (Figs. 1-A through 1-D). Nonunions treated with grafts that fail to provide either vascular supply or scaphoid length have not consistently achieved union 1,2. The free vascularized medial femoral condyle graft provides both structural support to restore scaphoid geometry and carpal alignment as well as blood supply to promote Fig. 1-A Fig. 1-C Fig. 1-B Fig. 1-D Figs. 1-A through 1-D A scaphoid waist nonunion with carpal collapse and proximal pole osteonecrosis. (Reprinted with permission of the Mayo Foundation.) Fig. 1-A Posteroanterior radiograph. Fig. 1-B Lateral radiograph Fig. 1-C Lateral computed tomographic scan. Fig. 1-D Coronal computed tomographic scan.

3 171 Fig. 2-B Fig. 2-A Fig. 2-A Scaphoid exposure through a palmar radial approach. (Redrawn and modified with permission of the Mayo Foundation.) Fig. 2-B Landmarks, including the flexor carpi radialis (FCR), the scaphoid, and the radial styloid, are identified. (Reprinted with permission of the Mayo Foundation.) Fig. 2-C A curvilinear incision or hockey-stick incision is made over the radial border of the flexor carpi radialis. (Reprinted with permission of the Mayo Foundation.) Fig. 2-C

4 172 union in this challenging subset of nonunions 3-5. SURGICAL TECHNIQUE The procedure is performed with the patient under general anesthesia. The patient is placed in the supine position with the affected arm draped free on a hand table. The ipsilateral lower extremity is prepared free from the proximal aspect of the thigh distally. A sandbag beneath the drapes is used to maintain knee flexion. The ipsilateral leg is selected for harvest of the medial femoral condyle graft, as it facilitates simultaneous work on both surgical sites and allows the use of a walking aid in the contralateral hand postoperatively, if necessary. Pneumatic tourniquets are placed on both the upper and lower extremities. Scaphoid Exposure and Preparation The upper extremity is exsanguinated with an Esmarch bandage, and the tourniquet is inflated. Hardware from previous procedures, if present, is removed through the prior incision. An extended volar Russetype approach to the scaphoid is used for graft placement and microvascular anastomosis to the radial artery and superficial vein 6 (Figs. 2-A, 2-B, and 2-C). The incision begins 8 cm proximal to the wrist, overlying and following the flexor carpi radialis Fig. 3-A Fig. 3-B Figs. 3-A and 3-B Approach to the scaphoid. The flexor carpi radialis (FCR) tendon is retracted ulnarly, and the radioscaphocapitate (RSC) and long radiolunate (LRL) ligaments are sharply divided. (Redrawn and modified [Fig. 3-A] and reprinted [Fig. 3-B] with permission of the Mayo Foundation.)

5 173 tendon. At the flexion crease, it curves slightly radially toward the thumb, ending at the trapezium. The flexor carpi radialis sheath is opened, the tendon is retracted ulnarly, and the floor of the flexor carpi radialis tunnel is sharply incised longitudinally to expose the radiocarpal joint at the level of the scaphoid (Figs. 3-A and 3-B). Visualization of the scaphoid is improved by making a volar capsulotomy in the scaphotrapezial joint. The scaphoid is then examined, with particular attention paid to the articular cartilage of the radioscaphoid and midcarpal joints as well as to the viability of the proximal pole of the scaphoid (Figs. 4-A and 4-B). The tourniquet can be released to evaluate for punctate bleeding. The absence of punctate bleeding from the proximal pole fragment suggests avascularity 7 and confirms the need to proceed with free vascularized grafting. The scaphoid is then prepared to accept the graft (Fig. 5). The dorsal intercalated segment instability deformity is corrected by flexing the wrist under fluoroscopic imaging until the radiolunate angle is neutral 8. A Kirschner wire is passed across the radiolunate articulation to hold the reduction (Figs. 6-A, 6-B, and 6-C). When the wrist is extended to a neutral position, the scaphoid nonunion site gaps open. Fibrous and necrotic tissue Fig. 4-A Fig. 4-B Fig. 4-A Scaphoid nonunion is exposed. (Redrawn and modified with permission of the Mayo Foundation.) Fig. 4-B The nonunion site is examined and the viability of and vascularity to the proximal pole are assessed. The tourniquet can be released to observe for the absence of punctate bleeding, suggesting osteonecrosis. (Reprinted with permission of the Mayo Foundation.)

6 174 Fig. 5 Scaphoid nonunion site is prepared to accept the graft. Fibrous and necrotic tissue is débrided, and the edges are prepared with a microsagittal saw. (Reprinted with permission of the Mayo Foundation.) Fig. 6-A Fig. 6-A Reduction of the humpback deformity. (Redrawn and modified with permission of the Mayo Foundation.)

7 175 is débrided from the nonunion site, and a sagittal saw is used to prepare flat surfaces to accept the graft. The size of the osseous defect is measured after gentle distraction of the fragments with a small lamina spreader. Graft Harvest and Preparation With the lower limb under tourniquet control, a medial longitudinal incision centered over the posterior border of the vastus medialis is made, extending from the palpable joint line proximally for 18 to 20 cm (Fig. 7). Once the quadriceps has been exposed, an incision through the vastus medialis fascia is made, and the muscle is lifted from its compartment anteriorly (Fig. 8). This maneuver exposes the vessels supplying the medial femoral condyle. They include the descending (or supreme) genicular artery, which originates from the superficial femoral artery just proximal to the adductor hiatus, and the medial superior genicular artery, which arises from the popliteal artery. The descending genicular artery provides a saphenous branch, traveling with the saphenous nerve, and one or more muscular branches. The osteoarticular branch anastomoses with the superior medial genicular artery at the proximal aspect of the condyle, together supplying the medial femoral condyle (Figs. 9-A and 9-B). It is necessary to evaluate the relative size of these two vessels, selecting the larger of the two with its venae comitantes as the vascular pedicle. This is most frequently the descending genicular artery. The selected artery and vein(s) are dissected from the condyle proximally and are followed toward the superficial femoral artery to provide a pedicle of sufficient length. Next, inspection of the condylar surface is easily performed extraarticularly, noting the circular pattern of periosteal vessels on its surface with numerous nutrient branches disappearing into the bone. A rectangular area of sufficient size to reconstruct the scaphoid defect is selected, containing one or more such Fig. 6-B Fig. 6-C Fig. 6-B The wrist is flexed until the lunate is in a neutral position relative to the radius, and then a in (1.6-mm) Kirschner wire is driven through the radius into the lunate to hold the reduction. (Reprinted with permission of the Mayo Foundation.) Fig. 6-C The wrist is then extended to neutral, allowing the scaphoid nonunion site to gap open revealing the size of the defect that needs to be grafted. (Reprinted with permission of the Mayo Foundation.)

8 176 Fig. 7 Exposure of the medial femoral condyle. A longitudinal incision is made over the medial aspect of the thigh from the articular edge of the femur extending 18 to 20 cm proximally. (Reprinted with permission of the Mayo Foundation.) Fig. 8 Approach to the medial femoral condyle. The incision is carried down through the fascia overlying the vastus medialis, which is then elevated anteriorly exposing the blood supply to the medial femoral condyle. (Reprinted with permission of the Mayo Foundation.)

9 177 Fig. 9-A Fig. 9-B Figs. 9-A and 9-B The vascular supply to the medial femoral condyle. Fig. 9-A The descending genicular and superior medial genicular vessels are identified, and the more robust vessels are selected for the vascular pedicle. (Redrawn and modified with permission of the Mayo Foundation.) Fig. 9-B Intraoperative photograph. (Reprinted with permission of the Mayo Foundation.) nutrient branches. The graft often measures 10 to 12 mm in all three dimensions and is usually centered over the distal posterior quadrant of the visible condyle, where the concentration of perforating vessels is highest. The medial collateral ligament of the knee arises in this area and must be identified and protected. The periosteum is sharply incised, and the bone is cut with use of

10 178 Fig. 10-A Fig. 10-B Figs. 10-A and 10-B Harvesting the graft. Fig. 10-A A rectangular area on the medial femoral condyle is marked out, the periosteum is sharply incised, and the graft is harvested with use of osteotomes or a microsagittal saw, taking care to retract and protect the vascular pedicle. (Redrawn and modified with permission of the Mayo Foundation.) Fig. 10-B Intraoperative photograph. (Reprinted with permission of the Mayo Foundation.) a small osteotome or sagittal saw. Care is taken to protect the vessels, elevating them from the more proximal bone with meticulous dissection prior to making the bone cuts (Figs. 10-A and 10-B). An additional cut is angled at 45 just distal to the graft to facilitate its removal with less risk of fracture (Figs. 11-A and 11-B). Once the graft has been elevated, the tourniquet is released to evaluate bleeding from the periosteum and the cancellous bone. The vascular pedicle

11 179 Figs. 11-A and 11-B Removal of the graft. Fig. 11-A An additional cut is made distal to the graft at 45, allowing the graft to be gently levered from the condyle in one piece without damaging the graft or the condyle. (Redrawn and modified with permission of the Mayo Foundation.) Fig. 11-B Intraoperative photograph. (Reprinted with permission of the Mayo Foundation.) Fig. 11-A Fig. 11-B

12 180 is then clamped, ligated, and divided at least 6 cm proximally (Fig. 12). Additional cancellous bone graft can be harvested as necessary to fill any defects in the proximal pole. The defect in the medial femoral condyle is then filled with a bone substitute of the surgeon s choice (e.g., Osteo- Set pellets, Wright Medical Technology, Arlington, Tennessee), and the wound is closed in a layered fashion with absorbable suture over a drain. A knee immobilizer is typically used in the immediate perioperative period for patient comfort. Graft Insetting and Fixation The radial artery and a vena comitans or the cephalic vein are exposed through the extended Russe incision. The graft is then further shaped by trial reduction to fit the precise dimensions of the scaphoid defect. Its periosteal surface should lie palmarly to preserve the blood supply and allow its underlying cortical bone to support the correction of the humpback deformity (Figs. 13-A and 13-B). A cannulated scaphoid screw is then placed, beginning with the guidewire, which is placed in retrograde fashion under fluoroscopic guidance (Figs. 14-A and 14-B). The screw is placed to secure the scaphoid and graft in appropriate alignment. Occasionally, Kirschner wires must be used in place of, or in addition to, screw fixation, depending on the size of the fracture fragments. The midcarpal and radioscaphoid joints are then carefully inspected for evidence of graft impingement, which can be corrected by removing small amounts of the graft in situ with a burr. Vascular Anastomosis An operative microscope is then brought in to complete the microvascular anastomosis. The vascular pedicle is trimmed to appropriate length. An arteriotomy is made in the radial artery, and an end-to-side anastomosis is performed with 9-0 nylon sutures. A microvenous repair is then performed in an end-to-end fashion to a vena comitans or the cephalic vein. Patency of the vessels and perfusion of the graft are visually confirmed prior to closure. The volar capsular incisions are reap- Fig. 12 The vascular pedicle is clipped and divided sharply proximally at least 6 cm. The graft is then trimmed to form a trapezoidal wedge based on the size of the scaphoid defect. (Reprinted with permission of the Mayo Foundation.)

13 181 proximated, if possible, without compromising the vascular pedicle, and the wound is then closed in layers over a drain. A bulky compression dressing with a thumb-spica long-arm splint is applied with the wrist in a neutral position. Postoperative Care The patient is allowed immediate weight-bearing. While weightbearing is painless, knee flexion The graft is inset into the scaphoid defect with the periosteal surface placed volarly (Fig. 13-A), and the vascular pedicle is anastomosed to the radial artery in an end-to-side fashion and the vein, to the vena comitans in an end-to-end fashion (Fig. 13-B). (Reprinted with permission of the Mayo Foundation.) Fig. 13-A Fig. 13-B

14 182 Fig. 14-A Fig. 14-B A cannulated screw is placed in a retrograde direction securing the scaphoid and graft in place, and its position is confirmed on anteroposterior (Fig. 14-A) and lateral fluoroscopic images (Fig. 14-B). (Reprinted with permission of the Mayo Foundation.) is initially uncomfortable. A knee immobilizer is helpful for a few days in some patients. A cane may be used in the contralateral hand as needed for support but is seldom necessary. Both are discontinued at the patient s discretion, generally a few days postoperatively. The sutures are removed at two weeks, and a Muenster or long arm thumbspica cast is maintained for three additional weeks. A short arm thumb-spica cast is then worn until union is confirmed. Radiographs are made at three to six-week intervals, and healing is confirmed by computed tomographic imaging (Figs. 15-A and 15-B). Intermittent splinting and progressive range-of-motion and strengthening exercises are initiated at that time. Fig. 15-A Fig. 15-B Posteroanterior (Fig. 15-A) and lateral (Fig. 15-B) radiographs, made twelve weeks postoperatively, confirm healing of the scaphoid nonunion. (Reprinted with permission of the Mayo Foundation.)

15 183 CRITICAL CONCEPTS INDICATIONS: This procedure is indicated in scaphoid nonunions associated with both scaphoid foreshortening and osteonecrosis of the proximal segment. Foreshortening, or humpback deformity, is defined as a lateral intrascaphoid angle of 45 (normal, 35 ). It is associated with a dorsal intercalated segment instability deformity, defined as a revised carpal height ratio of 1.52 (normal, 1.57 ± 0.05) or a radiolunate angle of 15 (normal, 10 ). Proximal pole avascularity is evidenced by the preoperative radiographic finding of increased bone density, occasionally associated with loss of trabecular structure, collapse of subchondral bone, and formation of bone cysts. Magnetic resonance imaging is generally helpful, with absent T1 and T2 signals and diminished uptake of contrast with gadolinium enhancement. The ultimate confirmation of avascularity occurs at the time of surgery by observation of white, sclerotic bone with absent punctate bleeding on tourniquet release. CONTRAINDICATIONS: Radiographic or intraoperative evidence of radioscaphoid arthritis. Salvage procedures, such as wrist denervation, scaphoid excision and four corner fusion, proximal row carpectomy, or complete wrist fusion, should be used in this instance. Ununited scaphoid fractures with normal geometry and proximal pole avascularity. These may be treated effectively with an inlay pedicled vascularized graft. Scaphoids with foreshortening but without evidence of osteonecrosis. These can be adequately treated with conventional (i.e., nonvascularized) wedge grafts and internal fixation. PITFALLS: Separation of the cortex and periosteum from the cancellous portion of the graft can occur while attempting to harvest the graft from the medial femoral condyle. The risk of this occurrence can be minimized by making the additional cut described, distal to the graft at 45, allowing the entire graft to be elevated as a unit from its deep surface, making it easier to remove the graft from the condyle. AUTHOR UPDATE: No changes in the technique have occurred since the publication of the original report. David B. Jones Jr., MD Allen T. Bishop, MD Alexander Y. Shin, MD Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street S.W., E14A, Rochester, MN address for A.Y. Shin: shin.alexander@mayo.edu Heinz Bürger, MD Facharzt für Unfallchirurgie, Radetzkystrasse 50, 9020 Klagenfurt, Austria The line drawings in this article are the work of Jennifer Fairman (jfairman@fairmanstudios.com). REFERENCES 1. 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: Merrell GA, Wolfe SW, Slade JF 3rd. Treatment of scaphoid nonunions: quantitative meta-analysis of the literature. J Hand Surg [Am]. 2002;27: Doi K, Oda T, Soo-Heong T, Nanda V. Free vascularized bone graft for nonunion of the scaphoid. J Hand Surg [Am]. 2000;25: Jones DB Jr, Bürger H, Bishop AT, Shin AY. Treatment of scaphoid waist nonunions with an avascular proximal pole and carpal collapse. A comparison of two vascularized bone grafts. J Bone Joint Surg Am. 2008;90: Larson AN, Bishop AT, Shin AY. Free medial femoral condyle bone grafting for scaphoid nonunions with humpback deformity and proximal pole avascular necrosis. Tech Hand Up Extrem Surg. 2007;11: Russe O. Fracture of the carpal navicular. Diagnosis, non-operative treatment, and operative treatment. J Bone Joint Surg Am. 1960;42: Green DP. The effect of avascular necrosis on Russe bone grafting for scaphoid nonunion. J Hand Surg [Am]. 1985;10: Tomaino MM, King J, Pizillo M. Correction of lunate malalignment when bone grafting scaphoid nonunion with humpback deformity: rationale and results of a technique revisited. J Hand Surg [Am]. 2000;25:322-9.