Eur J Trauma Emerg Surg DOI 10.1007/s00068-015-0587-8
REVIEW ARTICLE
Current concepts for the treatment of acute scaphoid fractures A. Arsalan‑Werner1 · M. Sauerbier1 · I. M. Mehling1
Received: 17 August 2015 / Accepted: 12 October 2015 © Springer-Verlag Berlin Heidelberg 2015
Abstract Fractures of the scaphoid are common injuries, accounting for approximately 80 % of carpal fractures. Differentiation between stable and unstable fractures (Herbert classification) cannot be made with conventional X-rays, so evaluation by computed tomography should additionally be performed. Under most circumstances, minimally invasive surgery with cannulated screws is the treatment of choice. A longer cast immobilization after minimal-invasive surgery is not necessary. Conservative treatment still has a place if the fracture is not dislocated nor unstable, but operative treatment can be offered to reduce the period of cast immobilization. Displaced fractures have a greater risk for nonunion and therefore should be treated operatively. Proximal pole fractures are definitely unstable, requiring treatment with screw fixation. The surgical approach depends on the location of the fracture and the preference of the surgeon. Keywords Scaphoid fracture · Herbert classification · Minimally invasive screw fixation · Cannulated screw · Scaphoid locking plate · CT scan
scaphoid serves as the keystone for wrist stability by linking the proximal row of bones to the distal row. Therefore, injury to this bone or its attachments might have long-term consequences, including nonunion, avascular necrosis and arthritis. The average age of patients sustaining scaphoid fractures is approximately 25 years with a range from 20 to 40 years [3, 4]. The incidence of this type of fracture is 38/100,000 per year [5]. Formerly, the therapy of choice for acute scaphoid fractures was conservative treatment with long periods of cast immobilization. Despite the well-recognized problems of scaphoid nonunion, it was argued that the majority of these fractures healed completely without complications [1, 6]. Achieving accurate internal fixation was considered difficult due to the small size and curved shape of the scaphoid. However, conservative treatment with cast immobilization for long intervals is often associated with joint stiffness and muscle atrophy, resulting in delays of patients’ return to work and resumption of normal daily activities.
Introduction
Anatomy
Fractures of the scaphoid are common injuries, accounting for approximately 80 % of all carpal fractures [1, 2]. The
The scaphoid is a main link in the proximal row of the carpus and plays an important role in the function of the wrist [7]. More than two-thirds of the surface of the scaphoid are covered by articular cartilage which should be considered when treating scaphoid fractures [1]. The primary blood supply originates from palmar and dorsal branches of the radial artery, but the proximal segment of the scaphoid is only supplied by retrograde flow. Thus, untreated scaphoid fractures of the proximal pole have a high nonunion rate [8, 9].
* M. Sauerbier michael.sauerbier@bgu‑frankfurt.de 1
Department for Plastic, Hand and Reconstructive Surgery, Hand Trauma Center, BG Trauma Center Frankfurt am Main, Academic Hospital Goethe University Frankfurt a. Main, Friedberger Landstrasse 430, 60389 Frankfurt am Main, Germany
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A. Arsalan-Werner et al. A1
A2
B1
B2
B3
B4
Fig. 1 CT-based classification of scaphoid fractures [10]. Reprinted with permission from Georg Thieme Verlag, Stuttgart, Germany [9]. Typ A: stable fractures. A1 Tubercle fracture, A2 non-displaced frac-
ture of the waist. Typ B: unstable fractures. B1 Transverse fracture, B2 displaced fracture of the waist, B3 fracture of the proximal pole, B4 trans-scaphoid perilunar dislocation
Diagnosis
foundation for optimal treatment decisions [10, 15]. Fractures in the middle third of the scaphoid are the most common, making up about 70 % of all scaphoid fractures, whereas 20 % are localized in the proximal third and only 10 % in the distal third [4]. Important for stability of the fracture are the direction of the fracture line and possible additional injuries to the carpal ligaments. According to the modified Krimmer/Herbert classification, fractures are classified as stable (type A) or unstable (type B). Horizontal–diagonal fractures and fractures of the distal third have a better prognosis than fractures of the middle third or vertical–diagonal fractures of the proximal third [4].
After assessing the patient clinically, e.g. for pain in the anatomical snuffbox region, a precise radiologic technique is mandatory to detect the fracture and to analyse its morphologic features. Scaphoid fractures are usually diagnosed by X-rays (dorsopalmar, lateral, and Stecher views), but some fractures remain radiographically occult. In patients with a high clinical probability of a scaphoid fracture, a computed tomography bone scan (CT) is performed to confirm the diagnosis. A sagittal cut, parallel to the long axis of the scaphoid with 0.5–1 mm section thickness, is the best way to investigate the fracture and any associated deformity [10, 11]. Using the latest CT technology with isotropic voxels and a slice thickness of 0.4–0.6 mm, the reconstruction of the scaphoid can even be used for surgical planning, which is not advised when using older CT devices [12]. MR imaging has an excellent sensitivity and specificity in detecting scaphoid fractures by depicting bone marrow abnormalities, but this technique has limitations in distinguishing purely trabecular fractures from cortical fractures [13]. Therefore, CT scan remains the gold standard for both fracture classification and planning of the treatment and surgical procedure.
Classification Several classifications have been proposed for the management of scaphoid fractures [14]. The alpha-numeric system of the Herbert classification—later modified by Krimmer/ Herbert to use CT scans rather than X-rays (Fig. 1)—combines fracture chronicity, anatomy, and stability to serve as the
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Treatment Conservative treatment by cast immobilisation below the elbow with thumb metacarpophalangeal joint inclusion remains a widely accepted method in the management of stable scaphoid fractures (A1 and A2) because the rate of healing is considered to be satisfactory. Conservative treatment appears to have an advantage over surgical treatment due to the possibility of numerous surgical complications, but conservative treatment with long immobilization periods results in nonunion from 1.5 to 37 % of the time [1]. Although cast immobilization is associated with low rates of morbidity and long-term disability, the time until patients can resume work and daily activities may also be prolonged compared to surgery. The fact that cast immobilization can frequently be found in the case histories of patients with scaphoid nonunions and subsequent carpal collapse (SNAC—wrist) [16] poses the question whether conservative treatment is an adequate choice for all fracture types.
Current concepts for the treatment of acute scaphoid fractures
Fig. 2 Treatment algorithm for scaphoid fractures
The introduction of intramedullary fixation with the Herbert screw [15, 17] represented a revolutionary development in scaphoid surgery. In the interim, cannulated screws have offered further improvement. Via minimally invasive screw fixation, even small displaced scaphoid fractures can be treated surgically, with subsequent advantages of early mobilization and faster return to work [2, 14, 18–20]. This fixation technique has been described in both anatomical and clinical studies with promising results [10, 11, 21–24]. Although percutaneous screw fixation is highly successful, both the surgeon and the patient must be aware that if the fracture is displaced further or reduced inadequately intraoperatively, an open reduction technique will be required subsequently (Fig. 2). Contraindications for minimally invasive screw fixation include displaced scaphoid fractures, scaphoid nonunions with sclerosis and cystic changes. For the latter ones, a fresh surface with bleeding needs to be established with a bone graft before rigid fixation can be performed. For these fractures, a fresh surface with bleeding needs to be established with a bone graft before rigid fixation can be performed.
Of note, operative treatment necessitates an unequivocal diagnosis and classification of fracture type, which subsequently guides choice of operative technique [25]. The combination of a high consolidation rate with almost no immobilization and the early return to work support the application of early surgical treatment with minimalinvasive screw fixation for scaphoid fractures type B1 and B2. This approach is also reasonable for type A2 if the patient desires operative treatment [10, 26–31]. Nevertheless, conservative treatment with immobilization for 6–8 weeks after a stable A2 fracture currently remains the first option. The economic and social cost of plaster immobilization after scaphoid fractures should not be underestimated, however, particularly because scaphoid fractures occur in young (and probably working) men. Fractures of the proximal pole (type B3) are considered unstable fractures [11, 32–34] and account for 20 % of all scaphoid fractures [4]. These fractures should be treated surgically by fixation with a screw from the dorsal
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A. Arsalan-Werner et al.
Fig. 3 20-year-old patient and active athlete with a non-displaced fracture of the waist (scaphoid fracture type A2). The patient asked for early fixation. a Preoperative CT scan. b Percutaneous insertion of a K-wire in a retrograde fashion from a minimal-invasive palmar approach. c Retrograde positioning of the K-wire under fluoroscopic
control (posteroanterior view). d Insertion of the cannulated screw along the K-wire. e Radiographic control postoperatively after screw placement in posteroanterior, oblique and lateral views. f CT scan 12 weeks after screw fixation shows a well-healed scaphoid fracture
approach to avoid injury to the vulnerable palmar carpal ligaments and the scaphoid blood supply [14, 32, 33, 35]. There are also some who prefer arthroscopic guidance during internal fixation of scaphoid fractures [36–38]. The proposed advantage of arthroscopic guidance could be the possibility of treating combined fractures of the scaphoid, including injuries of carpal ligaments. Complete ligament disruptions can be detected and treated directly with ligament reconstruction techniques. This technique is also used to confirm fracture reduction and to treat occult injuries [39].
The minimally invasive technique has two main advantages: first, the dorsal and palmar ligaments remain undamaged, and second, immobilization after surgery is usually not necessary [5, 35]. Indications for this approach include all fractures through the waist which are undisplaced or can be reduced by closed manipulation. We prefer the palmar approach for all waist fractures; however, proximal pole fractures should be addressed with screw fixation through the dorsal approach. For a palmar approach, the surgeon should be seated with his dominant hand at the outer end of the table. The continuous availability of X-ray control is an important prerequisite for the procedure. Surgery is performed under brachial plexus anaesthesia. The patient’s arm is abducted on a hand table in the supine position. This position extends the scaphoid, and ulnar deviation improves access to the distal scaphoid pole (Fig. 3b). A tourniquet at 300 mgHG is applied to the upper arm. The image intensifier C-arm is positioned with the wrist in the central axis. The quality of reduction can be
Surgical technique If the fracture is not dislocated, minimally invasive surgery is currently the most sophisticated treatment. This technique can be performed either through a palmar (Fig. 3) or dorsal (Fig. 4) approach.
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Current concepts for the treatment of acute scaphoid fractures
Fig. 4 A 65-year-old patient with a displaced scaphoid fracture of the waist (scaphoid fracture type B2). a preoperative CT scan and radiograph (posterioranterior, lateral view and Stecher view). b Intraoperative fluoroscopic images: insertion of an antegrade K-wire (posterioranterior view). c Radiographic control after placement of
a cannulated screw shows a good reduction and compression of the fracture (posterioranterior and lateral view). d 5 months after surgery: CT scan and radiograph (posterioranterior and lateral view) show a well-healed scaphoid fracture
checked radiographically at any time. If necessary, closed reduction is sometimes carefully performed using the joystick technique. The prominence of the scaphoid tubercle is marked, and an image converter is used to mark the scaphotrapeziotrapezoid (STT) joint radiographically. Then, an incision approximately 1 cm long is performed in the radiopalmar direction over the STT joint. A Kirschner wire is introduced palmarly (approximately 45° dorsally and 45° ulnarly in relation to the neutral plain), entering the distal scaphoid and directed proximally under permanent X-ray control. The wrist is positioned in extension and maximal ulnar deviation during this manoeuvre. An X-ray control of the Kirschner wire in different views (a.p., lateral and oblique) is mandatory before proceeding with further surgery. The intraosseous position must be checked in all planes by moving the wrist from supination into pronation. After confirming placement of the Kirschner wire, the surgeon can measure the length of the appropriate screw
with the measuring device. Usually, the correct screw length is 1–2 mm shorter than the measurement, which ensures that the screw head is situated below the scaphoid cartilage and cortical surface because a fracture gap will be compressed by the screw. In modern practice, predrilling is usually unnecessary. During the next stage of the procedure, the self-drilling screw is placed into the scaphoid, and the Kirschner wire is removed. Finally, X-ray control in at least three planes for confirmation of proper screw placement is mandatory. Wound cleansing is followed by skin suturing, after which the lower arm and wrist are wrapped in a sterile light dressing. The tourniquet is released and the arm elevated. Cast immobilization is not necessary, unless complications occurred during the procedure. Whether or not they are displaced, proximal pole fractures (scaphoid fractures type B3) are unstable fractures, and should be treated by internal fixation using a dorsal approach (Fig. 5). The capsule of the wrist is opened between the second and third extensor compartments to access the
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A. Arsalan-Werner et al.
Fig. 5 A 24-year-old patient with a proximal pole fracture (scaphoid fracture type B3). a Preoperative CT scan and radiograph (posterioranterior and lateral view). b Fluoroscopic control: insertion of an antegrade K-wire (posterioranterior and lateral view). c Radiographic
control after placement of a cannulated screw (posterioranterior and lateral view). d 4 months after surgery CT scan and radiography (posterioranterior, lateral and Stecher view) show a well-healed proximal pole fracture
scapholunate joint. By this approach, the proximal pole fragment can be clearly visualized. A mini cannulated screw, with a smaller diameter and a smaller thread than a traditional cannulated screw, should be used for fixation of the fracture. The screw should be buried underneath the cartilage at the proximal pole of the scaphoid. After surgery, the wrist is usually immobilized for a short period of 3–4 weeks in a scaphoid cast. When screw osteosynthesis is not possible (for example, in wedge and multifragmentary fractures or fractures with large pre-existing intraosseous cysts of the scaphoid [Fig. 6]), a special locking plate can be used instead (Medartis AG, Basel, Switzerland). The plate adjusts very well to the anatomy of the scaphoid. This new technology is an option for particularly difficult cases as a backup procedure. However, hardware
removal after scaphoid fracture fixation is often necessary due to mechanical disturbances caused by hardware prominence [40]. Bone grafting is rarely necessary in acute fractures. It may be used in comminuted fractures with a loss of bone.
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Rehabilitation Heavy manual work and sports activities, especially contact sports, should be avoided for the first 6 weeks after surgery. Additional X-rays are performed at the second day postoperatively as well as 6–8 weeks after surgery. We perform a CT control scan approximately 8 weeks postoperatively (Fig. 2). The fracture should be healed within 6–10 weeks. Immobilization is usually not necessary (scaphoid fractures
Current concepts for the treatment of acute scaphoid fractures
Fig. 6 A 45-year-old patient with a large pre-existing intraosseous cysts of the scaphoid and an acute fracture of the scaphoid. a Preoperative CT scan. b Intraoperative fluoroscopic control (posterioranterior view) shows a good reduction of the fracture after defect filling
with autologous bone graft from the iliac crest and a well-positioned scaphoid plate (Medartis AG, Basel, Switzerland). c The CT scan 4 months after surgery shows a well-healed scaphoid fracture
type A2, and minimal invasive approach in scaphoid fractures type B1 and B2) or is only applied for a short period of 4–6 weeks (scaphoid fractures type B3, open approach to fractures type B1 and B2).
for nonunion and should be treated operatively. Proximal pole fractures are by definition unstable fractures, so treatment with a stable osteosynthesis is mandatory.
Conclusion
Acknowledgments The authors thank medical student Jack Squiers for editing the manuscript and librarian Claudia Diemann-Paeth for assisting with the literature research. Compliance with ethical standards
When dealing with scaphoid fractures, a treatment algorithm is very useful (Fig. 2). The CT scan and its interpretation are the key factors for decision-making regarding therapeutic options. Any treatment discussion with the patient should include the suggestion that operative treatment may facilitate earlier return to previous activity levels as well as better functional status and, therefore, potentially higher patient satisfaction. Conservative treatment may be safer given its lower complication rate. This factor should be especially highlighted when patients have fractures for which surgical fixation is not a mandatory treatment (stable fractures Herbert/Krimmer A2) [23]. Displaced fractures, on the other hand, have a greater risk
Conflict of interest Prof. Dr. med. Dr. med. habil. M. Sauerbier has an advisory contract with Medartis AG, Basel, Switzerland. Dr. med. Annika Arsalan-Werner and PD Dr. med. Isabella M. Mehling declare that they have no conflict of interest. Ethical approval This article does not contain any studies with human participants or animals performed by any of the authors.
References 1. Baumeister HH, Greinemann H. Conservative treatment of scaphoid bone fracture of the wrist. Unfallchirurg. 1989;92(4):175–9.
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A. Arsalan-Werner et al. 2. Brauer RB, Dierking M, Werber KD. Use of the Herbert screw with the freehand method for osteosynthesis of acute scaphoid fracture. Unfallchirurg. 1997;100(10):776–81. 3. Rettig AC, Kollias SC. Internal fixation of acute stable scaphoid fractures in the athlete. Am J Sports Med. 1996;24(2):182–6. 4. Schaefer M. Siebert HR Fracture of the semilunar bone. Unfallchirurg. 2002;105(6):540–52. 5. Bond CD, et al. Percutaneous screw fixation or cast immobilization for nondisplaced scaphoid fractures. J Bone Joint Surg Am. 2001;83-A(4):483–8. 6. Lennert KH, Contzen H. Conservative treatment of fractures of the scaphoid bone — indications. Unfallchirurgie. 1988;14(3):148–50. 7. Berger RA. The anatomy of the scaphoid. Hand Clin. 2001;17(4):525–32. 8. Reigstad O, et al. Scaphoid non-unions, where do they come from? The epidemiology and initial presentation of 270 scaphoid non-unions. Hand Surg. 2012;17(3):331–5. 9. Mehling IM, Sauerbier M. Scaphoid fractures and pseudarthrosis of the scaphoid. Z Orthop Unfallchirurgie. 2013;151(6):639–60. 10. Krimmer H, Schmitt R, Herbert T. Scaphoid fractures: diagnosis, classification and therapy. Unfallchirurg. 2000;103(10):812–9. 11. Sauerbier M, Germann G, Dacho A. Current concepts in the treatment of scaphoid fractures. Eur J Trauma. 2004;2:80–92. 12. Schmitt R, Lanz U Bildgebende Diagnostik der Hand 2015, Stuttgart Georg Thieme Verlag KG. 13. Memarsadeghi M, et al. Occult scaphoid fractures: comparison of multidetector CT and MR imaging—initial experience. Radiology. 2006;240(1):169–76. 14. Herbert T. The fractured scaphoid 1990, St. Louis: quality medical publishing. 15. Herbert TJ, Fisher WE. Management of the fractured scaphoid using a new bone screw. J Bone Joint Surg Br. 1984;66(1):114–23. 16. Krimmer H. Post-traumatic carpal collapse: follow-up and therapeutic concept. Unfallchirurg. 2000;103(4):259. 17. Herbert TJ, Krimmer H. Scaphoid fractures—internal fixation using the Herbert screw system. In: Master techniques in orthopaedic surgery: the wrist. New York: Raven Press; 2000. 18. Bickert B, et al. Use of a cannulated 3.0 mm AO screw with an intraosseous support washer in osteosynthesis of the scaphoid: results and analysis of problems in 28 cases. Handchir Mikrochir Plast Chir. 2000;32(4):277–82. 19. Herbert TJ, Fisher WE, Leicester AW. The Herbert bone screw: a 10-year perspective. J Hand Surg Br. 1992;17(4):415–9. 20. Schädel-Hopfner M, Bohringer G, Gotzen L. Percutaneous osteosynthesis of scaphoid fracture with the Herbert-Whipple screw—technique and results. Handchir Mikrochir Plast Chir. 2000;32(4):271–6. 21. Bond CD, Shin CA. Percutaneous cannulated screw fixa tion of acute scaphoid fractures. Tech Hand Up Extrem Surg. 2000;4(2):81–7. 22. Chan KW, McAdams TR. Central screw placement in percutaneous screw scaphoid fixation: a cadaveric comparison of proximal and distal techniques. J Hand Surg Am. 2004;29(1):74–9.
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23. Kamineni S, Lavy CB. Percutaneous fixation of scaphoid fractures. An anatomical study. J Hand Surg Br. 1999;24(1):85–8. 24. Wozasek GE, Moser KD. Percutaneous screw fixation for fractures of the scaphoid. J Bone Joint Surg Br. 1991;73(1):138–42. 25. Barton NJ. Twenty questions about scaphoid fractures. J Hand Surg Br. 1992;17(3):289–310. 26. Wu WC. Percutaneous cannulated screw fixation of acute scaphoid fractures. Hand Surg. 2002;7(2):271–8. 27. Sauerbier M, Müller M. Scaphoid fractures: diagnosis, surgical approach, and complications. Zentralblatt Chir. 2007;132(3):W42–53. 28. Jeon IH, et al. Minimal invasive percutaneous Herbert screw fixation in acute unstable scaphoid fracture. Hand Surg. 2003;8(2):213–8. 29. Haddad FS, Goddard NJ. Acute percutaneous scaphoid fixation. A pilot study. J Bone Joint Surg Br. 1998;80(1):95–9. 30. Chung KC. A simplified approach for unstable scaphoid fracture fixation using the Acutrak screw. Plast Reconstr Surg. 2002;110(7):1697–703. 31. Adolfsson L, Lindau T, Arner M. Acutrak screw fixation versus cast immobilisation for undisplaced scaphoid waist fractures. J Hand Surg Br. 2001;26(3):192–5. 32. Krimmer H. Scaphoid fracture repair using the Herbert screw system (HBS). Atlas of the Hand Clin. 2003;8:57–66. 33. Krimmer H. Management of acute fractures and nonun ions of the proximal pole of the scaphoid. J Hand Surg Br. 2002;27(3):245–8. 34. Sauerbier M, et al. Midcarpal arthrodesis with complete scaphoid excision and interposition bone graft in the treatment of advanced carpal collapse (SNAC/SLAC wrist): operative technique and outcome assessment. J Hand Surg Br. 2000;25(4):341–5. 35. Sauerbier M, Werner A. Diagnosing and treating scaphoid fractures. Eur Musculoskelet Rev. 2011;6(2):120–4. 36. Slade JF, Gutow AP. Geissler WB Percutaneous internal fixation of scaphoid fractures via an arthroscopically assisted dorsal approach. J Bone Joint Surg Am. 2002;84-A(Suppl 2):21–36. 37. Slade JF, Grauer JN. Mahoney JD Arthroscopic reduction and percutaneous fixation of scaphoid fractures with a novel dorsal technique. Orthop Clin North Am. 2001;32(2):247–61. 38. Slade JF, et al. Percutaneous internal fixation of selected scaphoid nonunions with an arthroscopically assisted dorsal approach. J Bone Joint Surg Am. 2003;85-A(Suppl 4):20–32. 39. Geissler WB, et al. Scaphoid fractures: what’s hot, what’s not. J Bone Joint Surg Am. 2012;94(2):169–81. 40. Arnoldi V, et al. Erste Erfahrungen mit einer winkelstabilen Skaphoidspezialplatte. Kongr Dtsch Ges Handchir. Baden-Baden 2014. 41. Schädel-Hopfner M, et al. Operative versus conservative treatment of non-displaced fractures of the scaphoid bone. Results of a controlled multicenter cohort study. Unfallchirurg. 2010;113(10):804–6.
REVIEW ARTICLE
Current concepts for the treatment of acute scaphoid fractures A. Arsalan‑Werner1 · M. Sauerbier1 · I. M. Mehling1
Received: 17 August 2015 / Accepted: 12 October 2015 © Springer-Verlag Berlin Heidelberg 2015
Abstract Fractures of the scaphoid are common injuries, accounting for approximately 80 % of carpal fractures. Differentiation between stable and unstable fractures (Herbert classification) cannot be made with conventional X-rays, so evaluation by computed tomography should additionally be performed. Under most circumstances, minimally invasive surgery with cannulated screws is the treatment of choice. A longer cast immobilization after minimal-invasive surgery is not necessary. Conservative treatment still has a place if the fracture is not dislocated nor unstable, but operative treatment can be offered to reduce the period of cast immobilization. Displaced fractures have a greater risk for nonunion and therefore should be treated operatively. Proximal pole fractures are definitely unstable, requiring treatment with screw fixation. The surgical approach depends on the location of the fracture and the preference of the surgeon. Keywords Scaphoid fracture · Herbert classification · Minimally invasive screw fixation · Cannulated screw · Scaphoid locking plate · CT scan
scaphoid serves as the keystone for wrist stability by linking the proximal row of bones to the distal row. Therefore, injury to this bone or its attachments might have long-term consequences, including nonunion, avascular necrosis and arthritis. The average age of patients sustaining scaphoid fractures is approximately 25 years with a range from 20 to 40 years [3, 4]. The incidence of this type of fracture is 38/100,000 per year [5]. Formerly, the therapy of choice for acute scaphoid fractures was conservative treatment with long periods of cast immobilization. Despite the well-recognized problems of scaphoid nonunion, it was argued that the majority of these fractures healed completely without complications [1, 6]. Achieving accurate internal fixation was considered difficult due to the small size and curved shape of the scaphoid. However, conservative treatment with cast immobilization for long intervals is often associated with joint stiffness and muscle atrophy, resulting in delays of patients’ return to work and resumption of normal daily activities.
Introduction
Anatomy
Fractures of the scaphoid are common injuries, accounting for approximately 80 % of all carpal fractures [1, 2]. The
The scaphoid is a main link in the proximal row of the carpus and plays an important role in the function of the wrist [7]. More than two-thirds of the surface of the scaphoid are covered by articular cartilage which should be considered when treating scaphoid fractures [1]. The primary blood supply originates from palmar and dorsal branches of the radial artery, but the proximal segment of the scaphoid is only supplied by retrograde flow. Thus, untreated scaphoid fractures of the proximal pole have a high nonunion rate [8, 9].
* M. Sauerbier michael.sauerbier@bgu‑frankfurt.de 1
Department for Plastic, Hand and Reconstructive Surgery, Hand Trauma Center, BG Trauma Center Frankfurt am Main, Academic Hospital Goethe University Frankfurt a. Main, Friedberger Landstrasse 430, 60389 Frankfurt am Main, Germany
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A. Arsalan-Werner et al. A1
A2
B1
B2
B3
B4
Fig. 1 CT-based classification of scaphoid fractures [10]. Reprinted with permission from Georg Thieme Verlag, Stuttgart, Germany [9]. Typ A: stable fractures. A1 Tubercle fracture, A2 non-displaced frac-
ture of the waist. Typ B: unstable fractures. B1 Transverse fracture, B2 displaced fracture of the waist, B3 fracture of the proximal pole, B4 trans-scaphoid perilunar dislocation
Diagnosis
foundation for optimal treatment decisions [10, 15]. Fractures in the middle third of the scaphoid are the most common, making up about 70 % of all scaphoid fractures, whereas 20 % are localized in the proximal third and only 10 % in the distal third [4]. Important for stability of the fracture are the direction of the fracture line and possible additional injuries to the carpal ligaments. According to the modified Krimmer/Herbert classification, fractures are classified as stable (type A) or unstable (type B). Horizontal–diagonal fractures and fractures of the distal third have a better prognosis than fractures of the middle third or vertical–diagonal fractures of the proximal third [4].
After assessing the patient clinically, e.g. for pain in the anatomical snuffbox region, a precise radiologic technique is mandatory to detect the fracture and to analyse its morphologic features. Scaphoid fractures are usually diagnosed by X-rays (dorsopalmar, lateral, and Stecher views), but some fractures remain radiographically occult. In patients with a high clinical probability of a scaphoid fracture, a computed tomography bone scan (CT) is performed to confirm the diagnosis. A sagittal cut, parallel to the long axis of the scaphoid with 0.5–1 mm section thickness, is the best way to investigate the fracture and any associated deformity [10, 11]. Using the latest CT technology with isotropic voxels and a slice thickness of 0.4–0.6 mm, the reconstruction of the scaphoid can even be used for surgical planning, which is not advised when using older CT devices [12]. MR imaging has an excellent sensitivity and specificity in detecting scaphoid fractures by depicting bone marrow abnormalities, but this technique has limitations in distinguishing purely trabecular fractures from cortical fractures [13]. Therefore, CT scan remains the gold standard for both fracture classification and planning of the treatment and surgical procedure.
Classification Several classifications have been proposed for the management of scaphoid fractures [14]. The alpha-numeric system of the Herbert classification—later modified by Krimmer/ Herbert to use CT scans rather than X-rays (Fig. 1)—combines fracture chronicity, anatomy, and stability to serve as the
13
Treatment Conservative treatment by cast immobilisation below the elbow with thumb metacarpophalangeal joint inclusion remains a widely accepted method in the management of stable scaphoid fractures (A1 and A2) because the rate of healing is considered to be satisfactory. Conservative treatment appears to have an advantage over surgical treatment due to the possibility of numerous surgical complications, but conservative treatment with long immobilization periods results in nonunion from 1.5 to 37 % of the time [1]. Although cast immobilization is associated with low rates of morbidity and long-term disability, the time until patients can resume work and daily activities may also be prolonged compared to surgery. The fact that cast immobilization can frequently be found in the case histories of patients with scaphoid nonunions and subsequent carpal collapse (SNAC—wrist) [16] poses the question whether conservative treatment is an adequate choice for all fracture types.
Current concepts for the treatment of acute scaphoid fractures
Fig. 2 Treatment algorithm for scaphoid fractures
The introduction of intramedullary fixation with the Herbert screw [15, 17] represented a revolutionary development in scaphoid surgery. In the interim, cannulated screws have offered further improvement. Via minimally invasive screw fixation, even small displaced scaphoid fractures can be treated surgically, with subsequent advantages of early mobilization and faster return to work [2, 14, 18–20]. This fixation technique has been described in both anatomical and clinical studies with promising results [10, 11, 21–24]. Although percutaneous screw fixation is highly successful, both the surgeon and the patient must be aware that if the fracture is displaced further or reduced inadequately intraoperatively, an open reduction technique will be required subsequently (Fig. 2). Contraindications for minimally invasive screw fixation include displaced scaphoid fractures, scaphoid nonunions with sclerosis and cystic changes. For the latter ones, a fresh surface with bleeding needs to be established with a bone graft before rigid fixation can be performed. For these fractures, a fresh surface with bleeding needs to be established with a bone graft before rigid fixation can be performed.
Of note, operative treatment necessitates an unequivocal diagnosis and classification of fracture type, which subsequently guides choice of operative technique [25]. The combination of a high consolidation rate with almost no immobilization and the early return to work support the application of early surgical treatment with minimalinvasive screw fixation for scaphoid fractures type B1 and B2. This approach is also reasonable for type A2 if the patient desires operative treatment [10, 26–31]. Nevertheless, conservative treatment with immobilization for 6–8 weeks after a stable A2 fracture currently remains the first option. The economic and social cost of plaster immobilization after scaphoid fractures should not be underestimated, however, particularly because scaphoid fractures occur in young (and probably working) men. Fractures of the proximal pole (type B3) are considered unstable fractures [11, 32–34] and account for 20 % of all scaphoid fractures [4]. These fractures should be treated surgically by fixation with a screw from the dorsal
13
A. Arsalan-Werner et al.
Fig. 3 20-year-old patient and active athlete with a non-displaced fracture of the waist (scaphoid fracture type A2). The patient asked for early fixation. a Preoperative CT scan. b Percutaneous insertion of a K-wire in a retrograde fashion from a minimal-invasive palmar approach. c Retrograde positioning of the K-wire under fluoroscopic
control (posteroanterior view). d Insertion of the cannulated screw along the K-wire. e Radiographic control postoperatively after screw placement in posteroanterior, oblique and lateral views. f CT scan 12 weeks after screw fixation shows a well-healed scaphoid fracture
approach to avoid injury to the vulnerable palmar carpal ligaments and the scaphoid blood supply [14, 32, 33, 35]. There are also some who prefer arthroscopic guidance during internal fixation of scaphoid fractures [36–38]. The proposed advantage of arthroscopic guidance could be the possibility of treating combined fractures of the scaphoid, including injuries of carpal ligaments. Complete ligament disruptions can be detected and treated directly with ligament reconstruction techniques. This technique is also used to confirm fracture reduction and to treat occult injuries [39].
The minimally invasive technique has two main advantages: first, the dorsal and palmar ligaments remain undamaged, and second, immobilization after surgery is usually not necessary [5, 35]. Indications for this approach include all fractures through the waist which are undisplaced or can be reduced by closed manipulation. We prefer the palmar approach for all waist fractures; however, proximal pole fractures should be addressed with screw fixation through the dorsal approach. For a palmar approach, the surgeon should be seated with his dominant hand at the outer end of the table. The continuous availability of X-ray control is an important prerequisite for the procedure. Surgery is performed under brachial plexus anaesthesia. The patient’s arm is abducted on a hand table in the supine position. This position extends the scaphoid, and ulnar deviation improves access to the distal scaphoid pole (Fig. 3b). A tourniquet at 300 mgHG is applied to the upper arm. The image intensifier C-arm is positioned with the wrist in the central axis. The quality of reduction can be
Surgical technique If the fracture is not dislocated, minimally invasive surgery is currently the most sophisticated treatment. This technique can be performed either through a palmar (Fig. 3) or dorsal (Fig. 4) approach.
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Current concepts for the treatment of acute scaphoid fractures
Fig. 4 A 65-year-old patient with a displaced scaphoid fracture of the waist (scaphoid fracture type B2). a preoperative CT scan and radiograph (posterioranterior, lateral view and Stecher view). b Intraoperative fluoroscopic images: insertion of an antegrade K-wire (posterioranterior view). c Radiographic control after placement of
a cannulated screw shows a good reduction and compression of the fracture (posterioranterior and lateral view). d 5 months after surgery: CT scan and radiograph (posterioranterior and lateral view) show a well-healed scaphoid fracture
checked radiographically at any time. If necessary, closed reduction is sometimes carefully performed using the joystick technique. The prominence of the scaphoid tubercle is marked, and an image converter is used to mark the scaphotrapeziotrapezoid (STT) joint radiographically. Then, an incision approximately 1 cm long is performed in the radiopalmar direction over the STT joint. A Kirschner wire is introduced palmarly (approximately 45° dorsally and 45° ulnarly in relation to the neutral plain), entering the distal scaphoid and directed proximally under permanent X-ray control. The wrist is positioned in extension and maximal ulnar deviation during this manoeuvre. An X-ray control of the Kirschner wire in different views (a.p., lateral and oblique) is mandatory before proceeding with further surgery. The intraosseous position must be checked in all planes by moving the wrist from supination into pronation. After confirming placement of the Kirschner wire, the surgeon can measure the length of the appropriate screw
with the measuring device. Usually, the correct screw length is 1–2 mm shorter than the measurement, which ensures that the screw head is situated below the scaphoid cartilage and cortical surface because a fracture gap will be compressed by the screw. In modern practice, predrilling is usually unnecessary. During the next stage of the procedure, the self-drilling screw is placed into the scaphoid, and the Kirschner wire is removed. Finally, X-ray control in at least three planes for confirmation of proper screw placement is mandatory. Wound cleansing is followed by skin suturing, after which the lower arm and wrist are wrapped in a sterile light dressing. The tourniquet is released and the arm elevated. Cast immobilization is not necessary, unless complications occurred during the procedure. Whether or not they are displaced, proximal pole fractures (scaphoid fractures type B3) are unstable fractures, and should be treated by internal fixation using a dorsal approach (Fig. 5). The capsule of the wrist is opened between the second and third extensor compartments to access the
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A. Arsalan-Werner et al.
Fig. 5 A 24-year-old patient with a proximal pole fracture (scaphoid fracture type B3). a Preoperative CT scan and radiograph (posterioranterior and lateral view). b Fluoroscopic control: insertion of an antegrade K-wire (posterioranterior and lateral view). c Radiographic
control after placement of a cannulated screw (posterioranterior and lateral view). d 4 months after surgery CT scan and radiography (posterioranterior, lateral and Stecher view) show a well-healed proximal pole fracture
scapholunate joint. By this approach, the proximal pole fragment can be clearly visualized. A mini cannulated screw, with a smaller diameter and a smaller thread than a traditional cannulated screw, should be used for fixation of the fracture. The screw should be buried underneath the cartilage at the proximal pole of the scaphoid. After surgery, the wrist is usually immobilized for a short period of 3–4 weeks in a scaphoid cast. When screw osteosynthesis is not possible (for example, in wedge and multifragmentary fractures or fractures with large pre-existing intraosseous cysts of the scaphoid [Fig. 6]), a special locking plate can be used instead (Medartis AG, Basel, Switzerland). The plate adjusts very well to the anatomy of the scaphoid. This new technology is an option for particularly difficult cases as a backup procedure. However, hardware
removal after scaphoid fracture fixation is often necessary due to mechanical disturbances caused by hardware prominence [40]. Bone grafting is rarely necessary in acute fractures. It may be used in comminuted fractures with a loss of bone.
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Rehabilitation Heavy manual work and sports activities, especially contact sports, should be avoided for the first 6 weeks after surgery. Additional X-rays are performed at the second day postoperatively as well as 6–8 weeks after surgery. We perform a CT control scan approximately 8 weeks postoperatively (Fig. 2). The fracture should be healed within 6–10 weeks. Immobilization is usually not necessary (scaphoid fractures
Current concepts for the treatment of acute scaphoid fractures
Fig. 6 A 45-year-old patient with a large pre-existing intraosseous cysts of the scaphoid and an acute fracture of the scaphoid. a Preoperative CT scan. b Intraoperative fluoroscopic control (posterioranterior view) shows a good reduction of the fracture after defect filling
with autologous bone graft from the iliac crest and a well-positioned scaphoid plate (Medartis AG, Basel, Switzerland). c The CT scan 4 months after surgery shows a well-healed scaphoid fracture
type A2, and minimal invasive approach in scaphoid fractures type B1 and B2) or is only applied for a short period of 4–6 weeks (scaphoid fractures type B3, open approach to fractures type B1 and B2).
for nonunion and should be treated operatively. Proximal pole fractures are by definition unstable fractures, so treatment with a stable osteosynthesis is mandatory.
Conclusion
Acknowledgments The authors thank medical student Jack Squiers for editing the manuscript and librarian Claudia Diemann-Paeth for assisting with the literature research. Compliance with ethical standards
When dealing with scaphoid fractures, a treatment algorithm is very useful (Fig. 2). The CT scan and its interpretation are the key factors for decision-making regarding therapeutic options. Any treatment discussion with the patient should include the suggestion that operative treatment may facilitate earlier return to previous activity levels as well as better functional status and, therefore, potentially higher patient satisfaction. Conservative treatment may be safer given its lower complication rate. This factor should be especially highlighted when patients have fractures for which surgical fixation is not a mandatory treatment (stable fractures Herbert/Krimmer A2) [23]. Displaced fractures, on the other hand, have a greater risk
Conflict of interest Prof. Dr. med. Dr. med. habil. M. Sauerbier has an advisory contract with Medartis AG, Basel, Switzerland. Dr. med. Annika Arsalan-Werner and PD Dr. med. Isabella M. Mehling declare that they have no conflict of interest. Ethical approval This article does not contain any studies with human participants or animals performed by any of the authors.
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