Hong HKJOS Kong Journal of Orthopaedic Surgery 2002;6(2):86-90. SYMPOSIUM ON ADVANCES IN THE MANAGEMENT OF SCAPHOID PROBLEMS Minimal access means in treating transscaphoid perilunate fracture dislocation Department of Orthopaedics and Traumatology, Queen Elizabeth Hospital, Hong Kong ABSTRACT A minimally invasive technique with percutaneous screws and K-wire is an alternative to open reduction and fixation of fresh transscaphoid perilunate fracture dislocation. Anatomical reduction must be ensured before the percutaneous screw is inserted for the scaphoid fracture. Then K-wires are used to keep the ulnar side reduced. When difficulties are encountered intraoperatively, there is always an option of conversion to open surgery. Key Words: Dislocation; Fracture; Minimally invasive, surgical technique; Percutaneous; Transscaphoid perilunate!!"!#$%&'()*+,-./!"#$!%&'!"#$%&'()*++,-./0%12345*+6+789:;1/<=>?@abcde!"#$%&'()*+,-./012)345678 INTRODUCTION Transscaphoid perilunate fracture dislocation is one of the commonest patterns of fracture/fracture dislocations around the carpal bones. 2,9 The natural history is usually poor. Average functional score is usually poor. 1,3 Every single patient has posttraumatic arthritis. Attempts are made for perfect anatomical reduction, stable fixation, and early mobilisation. Because of the high percentage of loss of reduction (44% to 68%) and scaphoid nonunion (23% to 27%) with the plaster cast, 10 total reliance on plaster immobilisation is considered insufficient. Open reduction and internal fixation is a reasonable alternative to achieve anatomical reduction; 10 however, the soft tissue dissection further jeopardises the blood supply in addition to soft tissue trauma. A minimally invasive technique with closed reduction and percutaneous internal fixation can combine the advantages of minimal tissue dissection, rigid fixation, and early mobilisation. K-wire fixation has been recommended. Unfortunately, without good interfragmentary compression, healing is not guaranteed. The immobilisation period is unlikely to be shortened. With the reported success of percutaneous cannulated screw fixation in isolated scaphoid fracture (ie, 100% fracture union rate), 12 it seems reasonable that the percutaneous cannulated screw fixation technique can be further extended to the transscaphoid perilunate fracture dislocation. 10,11 MECHANISM Our patients fell on their outstretched hands, resulting in the dorsal type of transscaphoid perilunate fracture dislocation. The mechanism of injury is dorsiflexion, Correspondence: Dr. Y.L. Lam, Department of Orthopaedics and Traumatology, Queen Elizabeth Hospital, 30 Gascoigne Road, Kowloon, Hong Kong. 86 2002 Hong Kong Orthopaedic Association & Hong Kong College of Orthopaedic Surgeons.
Minimal access means in transscaphoid perilunate fracture dislocation ulnar deviation, and intercarpal supination. 2 The lesion progresses sequentially from the radial to the ulnar in direction. The worst case is lunate dislocation, which may be due to forceful reduction iatrogenically. The volar type of transscaphoid perilunate fracture dislocation is very rare. Falling on the dorsiflexed hand with supination of proximal row of carpus and forearm may be its mechanism. INITIAL TREAMENT In the first stage, the fracture dislocation is managed by closed reduction with a method recommended by Green. 2 After 5 to 10 minutes of continuous traction, the wrist is hyperextended on the distal carpal row with the lunate stabilised. While traction is maintained, gradual flexion will snap the capitate head back to its original position. Pronation of the distal carpal row on the forearm further stabilises the reduction. 9 SUBSEQUENT MINIMALLY INVASIVE APPROACH The use of a minimally invasive technique should always follow the principles of fracture dislocation management. Anatomical reduction of both fracture and dislocation is the prerequisite of success. In our experience, about 40% do have difficulty in obtaining or ascertaining the perfect anatomical reduction. 10 So preoperative consent for open reduction should be obtained. In cases of delayed union, the fracture dislocation is extremely difficult to reduce. Even open reduction may fail. We recommend the minimally invasive procedure only for the fresh injuries. For some of the scaphoid fractures that are located in the very proximal part or belong to the vertical oblique type, it is very difficult to insert the screw. 4 The best is transverse or horizontal oblique fracture in the middle third. INTRAOPERATIVE X-RAY SCREEN- ING Intraoperative X-ray screening is used to ensure the perfect anatomical reduction of fracture and anatomical alignment of a reduced dislocation. It is also essential in guiding our scaphoid screw insertion. Anteroposterior and lateral views are required to ensure joint reduction. The relationship between capitate and lunate and between scaphoid and lunate is well shown in the lateral film. The oblique views are essential for scaphoid alignment and scaphoid screw insertion. The 45 supination oblique view is the best one for detecting any screw protusion. 12 Occasionally, continuous screening is needed. CHOICE OF IMPLANTS K-wires are used to hold the reduced fracture temporarily and also as definitive percutaneous implants for the reduced joints. For the scaphoid fracture, a compression screw is used. Whether this is an AO screw, a Herbert screw, or an Alphatec screw depends on surgeon s preference and his personal experience. A cannulated screw is easier to insert. We used the 3.5- mm AO cannulated screw to fix the scaphoid because the screw head helps to achieve compression across the fracture. 6,8 If the proximal pole is longer than 10 mm, the partially threaded screw is used. Otherwise the fully threaded screw with an over-drilled, sliding, proximal hole is chosen for better compression. 12 PRINCIPLE OF FIXATION Because the path of injury goes from radial to ulnar in direction and through the waist of scaphoid and capitolunate and lunotriquetral joints, the fixation starts from radial side and proceeds to the ulnar side, following the path of the injury. We believe that fixation at two points along the path for immobilisation is the minimum required, but it is usually adequate. 10 Sometimes additional fixation points are added. The fractured scaphoid is fixed with a percutaneous cannulated screw. If there is a transradial styloid fracture as well, another percutaneous cannulated screw is used to fix this fracture. On the ulnar side, either the capitolunate or the lunotriquetral joint is stabilised by percutaneous K- wire. Capitolunate fixation is technically easier but the lunotriquetral is better in holding the reduction. Theoretically, using fewer K-wires can reduce the risk of infection. In our experience, we have not seen posttraumatic ulnar translation of carpus. 7 The intact palmar radiolunate ligaments may account for this observation. Hence, we do not use a K-wire to stabilise the radiolunate joint in the hope that this will minimise chondrolysis. We may also start early radiocarpal mobilisation in some stable fixation. 87
HKJOS Figure 1 The radiolunate joint is temporarily fixed with K-wire. Figure 3 Either the capitolunate or lunotriquetral joint is then fixed to stabilise the reduced dislocation. Figure 2 Scaphoid fracture reduced and fixed with K-wire temporarily. Figure 4 The guide pin of the cannulated screw is inserted along the longest axis of the bone. SURGICAL TECHNIQUE Surgery is done under general anaesthesia or brachial plexus block. Intravenous regional anaesthesia is not recommended for this technically demanding procedure. The operation time can be unexpectedly long. We have experienced a case that finished in 210 minutes. 10 Moreover, a certain percentage of patients may require conversion to open surgery. The patient lies supine with the injured limb abducted on the radiolucent arm board. Perfect anatomical reduction is checked under the fluoroscan before skin drapping. The lunate and the proximal scaphoid fragments are the keystones in the reconstruction. They 88
Minimal access means in transscaphoid perilunate fracture dislocation Figure 5 The scaphoid-fixing screw is inserted (the temporary K- wire and guide pin are removed before final compression). Figure 6 All temporary K-wires are removed before application of the synthetic cast. are very mobile, making the latter part of the surgery very difficult, so the first temporary fixing K-wire is driven percutaneously from the radius to the lunate across the radiolunate joint. 5 The lunate is fixed in neutral position (Fig. 1). If there is no radial styloid fracture, the fractured scaphoid is the first one to be fixed for reasons discussed above. In order to put the guide pin of the cannulated screw into the scaphoid s longest axis, the wrist is placed in supinated, ulnarly deviated and extended position. 12 Unfortunately, in this position, the reduced fracture dislocation returns back to the unreduced state. Hence, the scaphoid is fixed initially with another temporary K-wire in neutral wrist position after reduction of the fractured scaphoid (Fig. 2). The position of this K-wire should not be in the path of the screw to be inserted subsequently. This K-wire is later removed after the capitolunate or lunotriquetral fixation and after insertion of cannulated screw guide-pin, but before final tightening of the cannulated screw. Then we move to the ulnar side. Percutaneous K-wire is used to fix the capitolunate or the lunotriquetral joint in its reduced position (Fig. 3). After ensuring anatomical reduction of the scaphoid, the guide pin is inserted through a stab wound under the fluoroscopic guidance along the bone s longest axis (Fig. 4). The entry site is over the most radial and distal area of the scaphoid tubercle. The threaded guide pin is driven in distal to the proximal direction. The best angle of insertion is 40 to the sagittal plane and 45 to the coronal plane. 4 Different views are taken to ensure it is parallel to the longest axis 12 and has no cortex penetration. The length of the inserted part is measured. The scaphoid is finally fixed with a screw. A partially threaded or a fully threaded screw that is 2 mm shorter than the measured value is used. Final compression is done after removal of all temporary fixation pins and the guide pin (Figs. 5 and 6). 12 POSTOPERATIVE CARE Short arm plaster cast immobilisation is given after surgery to minimise K-wire breakage. For a very stable fixation, out-of-cast wrist mobilisation under a hand therapist s supervision may be allowed. Otherwise, the plaster cast is kept on for 6 weeks to ensure ligament healing. 10 Then, K-wire is removed and further mobilisation is started. As in pure scaphoid fracture, laborers are advised not to do heavy manual work in the first 3 months after surgery. 12 COMPLICATIONS All our patients (7 patients) had scaphoid fractures that united uneventfully. We had one patient who had a scapholunate angle greater than 60. Retrospectively, that was due to suboptimal reduction intraoperatively. 89
HKJOS For this reason, we would like to emphasise the importance of perfect anatomical reduction intraoperatively. CONCLUSION Percutaneous cannulated screw fixation is a technically demanding procedure that may be an alternative to open reduction of the fresh transscaphoid perilunate fracture dislocation. To get good results, perfect anatomical reduction is of utmost importance. Depending on the degree of difficulty encountered intraoperatively, there is always the option of conversion to open surgery. REFERENCES 1. Apergis E, Maris J, Theodoratos G, Pavlakis D, Antoriou N. Perilunate dislocations and fracture dislocations. Closed and early open reduction compared in 28 cases. Acta Orthop Scand 1997;275(Suppl):S55-9. 2. Green DP. Dorsal perilunate/volar lunate dislocation. In: Green DP, editor. Operative Hand Surgery. 3rd ed. New York: Churchill Living Stone; 1993:901-14. 3. Herzberg G, Comtet JJ, Linscheid RL, Amadio PC, Cooney WP, Stalder J. Perilunate dislocations and fracture dislocation: A multicentre study. J Hand Surg Am 1993;18:768-79. 4. Hung LK. Percutaneous screw fixation of acute scaphoid fractures. How I do it. Hong Kong J Orthop Surg 1998;2:54-7. 5. Linscheid RL, Retting ME. The treatment of displaced scaphoid non-union with trapezoided bone graft. In: Gelberman RH, editor. The Wrist Master Techniques in Orthopaedic Surgery. New York: Rowen Press; 1994:119-31. 6. Rankin G, Kwechner SH, Orlando C, McKellop H, Brian WW, Sherman R, A biomechanical evaluation of a cannulated compressive screw for use in fractures of scaphoid. J Hand Surg Am 1991;16:1002-10. 7. Rayhack JH, Linscheid RL, Dobyns JH, Smith JH. Post-traumatic ulnar translation of carpus. J Hand Surg Am 1981;12: 180-9. 8. Shaw JA. Biomechanical comparison of cannulated small bone screws: a brief follow up study. J Hand Surg Am 1991; 16:998-1001. 9. Viegas SF. Carpal Instabilities. In: Marske PR, editor. Hand Surgery Update. Republished edition. Rosemont: American Academy of Orthopaedic Surgeons; 1996: 93-104. 10. Wong JKF, Lam YL, So TYC, Chik A. Internal minimal invasive fixation in transcaphoid perilunate fracture dislocation. In: Ege R, editor. Proceeding of Federation of Societies of Surgery of Hand (IFSSH). Ankara: THK C.o.; 2001:346-9. 11. Wu WC, Ko Y, Lam CK, Au KM. Transcaphoid perilunate fracture dislocation treated by a new surgical method:closedreduction, percutaneous cannulated screw and K-wire fixation. Hong Kong J Orthop Surg 1998;2:137-41. 12. Yip HSF, Wu WC, Chang RYP, So TYC. Percutaneous cannulated screw fixation of acute scaphoid waist fracture. J Hand Surg Br 2002;27:42-5. The Authors LAM Ying-Lee, MBChB, FHKCOS, Senior Medical Officer, Department of Orthopaedics and Traumatology, Queen Elizabeth Hospital, Hong Kong. CHANG Yun-Po Robert, MBBS, FHKCOS, Consultant, Department of Orthopaedics and Traumatology, Queen Elizabeth Hospital, Hong Kong. SO Yat-Cheong Timothy, FHKCOS, FRACS, Chief of Service and Consultant, Department of Orthopaedics and Traumatology, Queen Elizabeth Hospital, Hong Kong. 90