Four-corner arthrodesis with scaphoid excision has become a classic surgical treatment for scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC).1 This procedure is indicated in patients with nondissociative carpal instability after unsuccessful soft tissue reconstruction and those with arthritic involvement of the radioscaphoid joint, with or without capitolunate involvement, chronic dynamic carpal instability, or chronic perilunar instability that is not amenable to soft tissue procedures. Absolute contra-indications to 4-corner arthrodesis include ulnar translocation of the carpus and degenerative changes of the radiolunate, observed intraoperatively or on preoperative radiographs.2,3 Techniques for performing 4-corner arthrodesis involve multiple fixation options, such as headless compression screws, staples, Kirschner wires (K-wires), and circular plate fixation, each with varying reports of success and complications.4,5 Four-corner arthrodesis offers good pain relief in conjunction with preservation of partial wrist motion (flexion-extension arc average of the contralateral extremity, 41%) and grip strength (grip strength average of the contralateral extremity, 67%).6 However, complications occur and can be attributed to non-union at the intercarpal arthrodesis sites.6,7 To prevent this complication, stable fixation and adequate immobilization of the bones must be included within the fusion mass. One technique for performing this procedure involves fixation with a circular plate.8 Recently, a few studies identified higher complication rates and lower union rates when circular plates were used, compared with traditional methods of fixation.7,9–11
This study assessed the incidence of dorsal impingement between the circular plate and the radial lip, nonunion in the fusion mass, loose hardware, broken screws, and limitation in wrist motion associated with inadequate surgical capitolunate reduction.
Materials and Methods
Between 2004 and 2013, 36 patients underwent 4-corner arthrodesis with a circular plate. Surgical indications were SLAC (3 patients), SNAC (32 patients), and sequelae of irreducible perilunate dislocation (1 patient) (Figure 1). All of the patients were men, with a mean age of 48 years (range, 35–68 years). The right side was affected in 27 cases and the left side in 9. The dominant wrist was involved in 31 patients. Average follow-up was 56 months (range, 12–108 months). Surgical treatment included 4-corner arthrodesis with a circular plate (Spider Limited Wrist Arthrodesis System; Kinetikos Medical, San Diego, California) and bone grafting (Figure 2).
Preoperative anteroposterior radiograph showing a wrist with a nonunion scaphoid advanced collapse.
Postoperative anteroposterior (A) and lateral (B) radiographs after 4-corner arthrodesis with a circular plate and bone graft. The lateral view shows the plate inset below the dorsal cortex of the lunate.
A dorsal midline incision is made in line with the third metacarpal. Sharp dissection is carried down to the retinaculum. Subcutaneous tissue is elevated off the retinaculum on either side, with care taken to protect the radial and ulnar sensory nerves. The extensor pollicis longus tendon is released and transposed. The fourth compartment is opened, and its tendons are retracted ulnarly. The capsule is opened with a radial-based flap to preserve the dorsal ligaments. The scaphoid is excised, and the dorsal intercalated segment instability position of the lunate is corrected with use of a K-wire as a joystick. The current authors maintained the reduction with the joystick method.2 Under fluoroscopy, a lateral view of the flexed wrist is obtained. The wrist is flexed and deviated slightly ulnarly until neutral alignment of the radius and lunate is seen. A K-wire is then drilled from the dorsal distal radius into the lunate, with the lunate held in the reduced position. With the K-wire in place, the wrist is extended and neutral alignment of the radiolunate joint is preserved. The 4-corner area of the carpus is stabilized with K-wires. A fine rongeur is used to denude all articulations down to bleeding cancellous bone. The plate-specific rasp is centered on the 4-corner area and reamed until the rasp is seated below the dorsal lip of the lunate. A small curette is used to remove debris from the 4-corner joints. Bone graft is packed into the articulations. A circular plate is placed so that 2 screws can be placed into each of the 4 carpals. A 1.5-mm drill is used, followed by 2.4-mm screws. Intraoperative fluoroscopy is used to confirm carpal alignment, plate position, and screw length. Both the center of the plate and the surrounding area are filled with remaining bone graft (Figure 3). The capsule, retinaculum, and skin are closed, and the wrist is immobilized for 4 to 6 weeks.
Intraoperative dorsal photographs. A conical rasp is used to burr out an accepting bed for the circular plate (A). The circular plate is placed, the bones are drilled, and screws are placed (B).
Functional outcomes that were evaluated included pain, range of motion, grip strength, Disabilities of the Arm, Shoulder and Hand (DASH) score, and time to union. Pain was evaluated with the visual analog scale, with scores ranging from none (0) to severe (10). Grip strength was measured with a Jamar dynamometer (Sammons Preston, Inc, Bolingbrook, Illinois). Wrist motion in flexion and extension was measured with a handheld goniometer aligned with the third metacarpal. The goniometer was placed dorsally on the wrist to measure flexion and placed palmarly to measure extension.
Anteroposterior and lateral radiographs were obtained and evaluated for the presence of arthrosis, nonunion, hardware failure, and dorsal impingement. Radiographic union was assessed for the primary fusion mass, defined as union of the lunate and capitate. The secondary fusion mass was defined as the primary fusion mass plus union of the hamate and triquetrum. These definitions were used because successful clinical results rely on fusion of the lunate and capitate, whereas incorporation of either the hamate or the triquetrum is not required for long-term stability of the carpus.
To determine whether the position of the lunate relative to the capitate and radius within the 4-corner arthrodesis had an effect on subsequent range of motion, the capitate-lunate angle was measured on postoperative radiographs. On lateral wrist radiographs, the orientation of the longitudinal axis of the capitate relative to the longitudinal axis of the lunate creates an angle, the capitolunate angle, which normally measures between 0° and 30°. The wrist must be in the neutral position. Normally, the distal radius, lunate, capitate, and third metacarpal are colinear.12 The Pearson correlation coefficient showed correlation between the measured capitate-lunate angle and subsequent flexion and extension.
Other data collected included work status (return to the same occupation), bone union status, complications, and reoperations.
Of the patients, 27 were pain-free and 9 had pain with activity. Mean visual analog scale score was 7 (range, 5–9) preoperatively and 1 (range, 0–2) postoperatively. Average wrist range of motion was 42° in extension, 36° in flexion, 15° in ulnar deviation, and 12° in radial deviation. Mean grip strength was 34 kg preoperatively, 50 kg postoperatively, and 56 kg contralaterally.
Radiographs showed union in 35 cases. One patient had nonunion with loose hardware in the plate that needed revision surgery. The authors used bone graft from the distal radius in 25 patients and graft from the scaphoid in the other 11. Degenerative changes at the radiolunate articulation occurred in 1 patient 62 months after surgery, but the patient was asymptomatic. Mean capitolunate angle was 38º preoperatively and 9º postoperatively (range, 36º flexion and 42º extension). Poor correlation was found between the measured capitate-lunate angle and subsequent flexion and extension (r=0.32 and r=0.17, respectively) with the Pearson correlation coefficient. The authors found 1 or 2 broken screws in 3 cases (8.3%) (Figure 4) and hardware dorsal impingement between the circular plate and the dorsal lip of the radius in 6 cases (16.6%) (Figure 5). These cases were associated with incorrect or imperfect reduction in the capitolunate joint that impinged on wrist extension.
Postoperative lateral (A) and anteroposterior (B) radiographs showing breakage of the circular plate screw.
Postoperative lateral radiograph showing dorsal impingement of the plate against the lip of the distal radius.
Mean DASH score was 24 of 100. Overall subjective patient satisfaction with the treatment outcome was 70%. Patients were asked to rate their overall satisfaction as very satisfied, satisfied, dissatisfied, or very dissatisfied. No flexor digitorum tendon ruptures were reported.
The classic surgical procedure, as described by Watson and Ballet,1 involves excision of the scaphoid, with fusion of the capitate, hamate, lunate, and triquetrum and K-wire fixation and distal radius bone grafting. Since the original description of 4-corner arthrodesis, staples, headless compression screws, and circular plate fixation have been introduced as alternatives to K-wire fixation. Ashmead et al13 noted a 3% nonunion rate in 100 patients treated with K-wires. Krakauer et al4 described 2 nonunions in 23 patients who underwent fixation with K-wires, multiple Herbert screws, and staples. In a report by Wyrick et al,14 of 17 patients who underwent fixation with K-wires and staples, 3 had nonunion. The purported advantages of plate fixation include more stable fixation with less chance of non-union.15,16 Reported union rates with a circular plate were 63%,9 26%,10 and 25%.7 De Smet et al17 noted that plate fixation was associated with worse range of motion compared with K-wire or screw fixation. Recently, Xu et al18 evaluated the results of carpal collapse with a 4-corner concentrator of nickel-titanium memory alloy. This method of arthrodesis provides compressive force, eliminates gaps between the carpals to be fused, and preserves most wrist motion.
The current authors attribute their results with 4-corner arthrodesis to technical factors and the choice of fixation. The other 2 important factors are capitolunate reduction and the quality of bone graft.
The position of the lunate in the fusion mass has been a subject of study. The lunate usually rests in an extended, dorsal intercalated segment instability position in wrists with SLAC and SNAC. In a clinical review of 4-corner arthrodesis, Wyrick et al14 noted that the postoperative capitolunate angle ranged from 20º lunate flexion to 30º extension, but found no statistical correlation between lunate position and ultimate wrist motion. In a cadaveric study by De Carli et al,19 the authors found that the total arc of motion of the fused wrist was unaffected by fusing the lunate in the neutral position, 30º extension, or 20º flexion. However, the extended lunate position improved flexion at the expense of extension. The flexed lunate had the opposite effect, improving extension and decreasing flexion.
Another critical factor in 4-corner arthrodesis is the source of bone graft used for fusion. A classic description of 4-corner arthrodesis used cancellous bone graft from Lister's tubercle in the distal radius, but other patients received cancellous bone graft from the excised scaphoid. This morcellized scaphoid bone graft should be avoided.8 The authors agree that an adequate quantity of bone graft is needed. One option is bone graft from the distal radius obtained in all directions by curette. Graft is packed into the areas between the carpal bones and placed over the top of the plate after screw placement. Autologous cancellous grafts are the most effective grafting material because they are osteoconductive and osteoinductive and contain living osteogenic cells. Distal radius graft allows for a single incision. Autogenous iliac crest graft is more dense and has greater numbers of osteogenic cells, although it requires additional surgery that is often more painful than the wrist surgery. Despite the histomorphogenic differences in iliac crest and distal radius bone graft, clinical studies have shown both to be effective in arthrodesis.20
In a cadaveric study, Scobercea et al21 showed the biomechanical effect of triquetral and scaphoid excision on simulated midcarpal arthrodesis. When performing 4-corner arthrodesis, scaphoid and triquetrum excision may improve motion at the cost of increased mean radiolunate contact pressure. The same results were noted by Skie et al.22 Several biomechanical studies of 4-corner arthrodesis focused on transfer of the lunate positioning load to the radiolunate joint.23,24
Greenberg et al6 simulated 4-corner arthrodesis in a cadaveric model with 2 configurations of headless compression screw fixation and tested initial fixation strength by reproducing early postoperative wrist motion. In this biomechanical model, cannulated compression screws effectively resisted significant intercarpal gapping during early motion after 4-corner arthrodesis. The authors concluded that early gentle range of motion may be possible immediately after 4-corner arthrodesis with a construct of headless compression screws. A similar biomechanical study by Kraisarin et al25 evaluated immediate range of motion after 4-corner arthrodesis with dorsal circular plates vs K-wire fixation. In this study, 6 specimens had K-wire fixation, 6 had a dorsal circular plate, and 6 had a locked dorsal circular plate. All underwent 5000 cycles to simulate gentle wrist motion in the first 6 weeks. Each wrist specimen was mounted onto an MTS servohydraulic testing apparatus (MTS-System Corp, Eden Prarie, Minnesota), which is a wrist simulator and gap measurer. The wrist flexors and extensors were loaded with a total of 20 N throughout the cycling. This was used to approximate the compressive force across the radiocarpal joint in normal wrist flexion and extension. Cycling was performed at 1 cycle/s. One cycle consisted of the MTS pneumatic arm lowering, thus bringing the wrist into 20º extension, and then the pneumatic arm rising, bringing the wrist into 40º flexion. Each construct was measured before MTS testing at 0 cycles and after 100, 1000, and 5000 cycles. The authors found that 5 of the 6 specimens in the K-wire group had either hardware breakage or intercarpal gapping. Mean intercarpal gapping in the K-wire group was 3.6 to 2.2 mm and in the dorsal circular plate group was 1.9 to 1.2 mm. The locked dorsal circular plate group showed significantly less displacement than the other 2 groups.
Gaston et al26 reported on screw migration in patients after capitolunate arthrodesis with excision of the scaphoid and triquetrum. Of the 26 patients, 5 had subsequent proximal screw migration requiring screw removal, and 2 of them required subsequent wrist arthrodesis. Other authors also reported screw migration.27,28
Scaphoid excision and 4-corner arthrodesis with circular plate fixation in degenerative arthritis of the wrist is an effective surgical procedure, with high fusion rates. However, insertion of this implant to avoid loose hardware or impingement is technically demanding. The study findings suggest that inadequate reduction of the dorsal intercalated segment instability deformity at the time of arthrodesis causes impingement between the plate and the dorsal lip of the radius, with a reduction in wrist extension. If the capitolunate joint cannot be corrected with a circular plate, the authors recommend 4-corner arthrodesis with headless compression screws.
- Watson HK, Ballet FL. The SLAC wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg Am. 1984; 9(3):358–365. doi:10.1016/S0363-5023(84)80223-3 [CrossRef]
- Shin AY. Four-corner arthrodesis. J Am Soc Surg Hand. 2001; 1(2):93–111. doi:10.1053/jssh.2001.23905 [CrossRef]
- Collins ED, Nolla J. Spider plate fixation: no significant improvement in limited wrist arthrodesis. Tech Hand Up Extrem Surg. 2008; 12(2):94–99. doi:10.1097/BTH.0b013e31815e4580 [CrossRef]
- Krakauer JD, Bishop AT, Cooney WP. Surgical treatment of scapholunate advanced collapse. J Hand Surg Am. 1994; 19(5):751–759. doi:10.1016/0363-5023(94)90178-3 [CrossRef]
- del Piñal F, Klausmeyer M, Thans C, Moraleda E, Galindo C. Early experience with (dry) arthroscopic 4-corner arthrodesis: from a 4-hour operation to a tourniquet time. J Hand Surg Am. 2012; 37(11):2389–2399. doi:10.1016/j.jhsa.2012.08.026 [CrossRef]
- Greenberg A, Shreve M, Bazylewicz D, Goldstein R, Sapienza A. Early motion following 4-corner arthrodesis using cannulated compression screws: a biomechanical study. J Hand Surg Am. 2013; 38(11):2180–2187. doi:10.1016/j.jhsa.2013.08.105 [CrossRef]
- Shindle MR, Burton KJ, Weiland AJ, Domb BG, Wolfe SW. Complications of circular plate fixation for four-corner arthrodesis. J Hand Surg Eur Vol. 2007; 32(1):50–53. doi:10.1016/j.jhsb.2006.08.016 [CrossRef]
- Merrell GA, McDermott EM, Weiss AP. Four-corner arthrodesis using a circular plate and distal radius bone grafting: a consecutive case series. J Hand Surg Am. 2008; 33(5):635–642. doi:10.1016/j.jhsa.2008.02.001 [CrossRef]
- Kendall CB, Brown TR, Millon SJ, Rudisill LE Jr, Sanders JL, Tanner SL. Results of four-corner arthrodesis using dorsal circular plate fixation. J Hand Surg Am. 2005; 30(5):903–907. doi:10.1016/j.jhsa.2005.04.007 [CrossRef]
- Vance MC, Hernández JD, Didonna ML, Stern PJ. Complications and outcomes of four-corner arthrodesis: circular plate fixation versus traditional techniques. J Hand Surg Am. 2005; 30(6):1122–1127. doi:10.1016/j.jhsa.2005.08.007 [CrossRef]
- Skie M, Grothaus M, Ciocanel D, Goel V. Scaphoid excision with four-corner fusion: a biomechanical study. Hand (N Y). 2007; 2(4):194–198. doi:10.1007/s11552-007-9048-0 [CrossRef]
- Larsen CF, Stigsby B, Lindequist S, Bellstrørn T, Mathiesen FK, Ipsen T. Observer variability in measurements of carpal bone angles on lateral wrist radiographs. J Hand Surg Am. 1991; 16(5):893–898. doi:10.1016/S0363-5023(10)80157-1 [CrossRef]
- Ashmead D IV, Watson HK, Damon C, Herber S, Paly W. Scapholunate advanced collapse wrist salvage. J Hand Surg Am. 1994; 19(5):741–750. doi:10.1016/0363-5023(94)90177-5 [CrossRef]
- Wyrick JD, Stern PJ, Kiefhaber TR. Motion-preserving procedures in the treatment of scapholunate advanced collapse wrist: proximal row carpectomy versus four-corner arthrodesis. J Hand Surg Am. 1995; 20(6):965–970. doi:10.1016/S0363-5023(05)80144-3 [CrossRef]
- Bedford B, Yang SS. High fusion rates with circular plate fixation for four-corner arthrodesis of the wrist. Clin Orthop Relat Res. 2010; 468(1):163–168. doi:10.1007/s11999-009-1139-5 [CrossRef]
- Strauch RJ. Scapholunate advanced collapse and scaphoid nonunion advanced collapse arthritis: update on evaluation and treatment. J Hand Surg Am. 2011; 36(4):729–735. doi:10.1016/j.jhsa.2011.01.018 [CrossRef]
- De Smet L, Deprez P, Duerinckx J, Degreef I. Outcome of four-corner arthrodesis for advanced carpal collapse: circular plate versus traditional techniques. Acta Orthop Belg. 2009; 75(3):323–327.
- Xu YQ, Qi BC, Fan XY, Xu XS, Lu S, Ding J. Four-corner arthrodesis concentrator of nickel-titanium memory alloy for carpal collapse: a report of 18 cases. J Hand Surg Am. 2012; 37(11): 2246–2251. doi:10.1016/j.jhsa.2012.07.040 [CrossRef]
- De Carli P, Donndorff AG, Alfie VA, Boretto JG, López-Ovenza JM, Gallucci GL. Four-corner arthrodesis: influence of the position of the lunate on postoperative wrist motion: a cadaveric study. J Hand Surg Am. 2007; 32(9):1356–1362. doi:10.1016/j.jhsa.2007.08.004 [CrossRef]
- Biddulph SL. Bone donor site: iliac crest or distal radius?J Hand Surg Br. 1999; 24:645–646. doi:10.1054/jhsb.1999.0280 [CrossRef]
- Scobercea RG, Budoff JE, Hipp JA. Biomechanical effects of triquetral and scaphoid excision on simulated midcarpal arthrodesis in cadavers. J Hand Surg Am. 2009; 34(3):381–386. doi:10.1016/j.jhsa.2008.11.027 [CrossRef]
- Skie MC, Gove N, Ciocanel DE, Smith H. Management of non-united four-corner fusions. Hand (N Y). 2007; 2(1):34–38. doi:10.1007/s11552-007-9021-y [CrossRef]
- Dvinskikh NA, Blankevoort L, Strackee SD, Grimbergen CA, Streekstra GJ. The effect of lunate position on range of motion after a four-corner arthrodesis: a biomechanical simulation study. J Biomech. 2011; 44(7):1387–1392. doi:10.1016/j.jbiomech.2010.12.025 [CrossRef]
- Cohen MS, Werner FW, Sutton LG, Short WH. Scaphoid excision and midcarpal arthrodesis: the effect of triquetral excision. A biomechanical study. J Hand Surg Am. 2012; 37(3):493–499. doi:10.1016/j.jhsa.2011.12.032 [CrossRef]
- Kraisarin J, Dennison DG, Berglund LJ, An KN, Shin AY. Biomechanical comparison of three fixation techniques used for four-corner arthrodesis. J Hand Surg Eur Vol. 2011; 36(7):560–567. doi:10.1177/1753193411406799 [CrossRef]
- Gaston RG, Greenberg JA, Baltera RM, Mih A, Hasting H. Clinical outcomes of scaphoid and triquetral excision with capitolunate arthrodesis versus scaphoid excision and four-corner arthrodesis. J Hand Surg Am. 2009; 34(8):1407–1412. doi:10.1016/j.jhsa.2009.05.018 [CrossRef]
- Richards AA, Afifi AM, Moneim MS. Four-corner fusion and scaphoid excision using headless compression screws for SLAC and SNAC wrist deformities. Tech Hand Up Extrem Surg. 2011; 15(2):99–103. doi:10.1097/BTH.0b013e3181f60fec [CrossRef]
- Ozyurekoglu T, Turker T. Results of a method of 4-corner arthrodesis using headless compression screws. J Hand Surg Am. 2012; 37(3):486–492. doi:10.1016/j.jhsa.2011.12.022 [CrossRef]