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Management of scaphoid fractures: a review and update.

The scaphoid is the most commonly injured carpal bone. Almost half of all bony wrist injuries involve the scaphoid. Treatment is controversial and, when inadequate, can result in a painful nonunion or degenerative radiocarpal arthritis. Fracture of the scaphoid occurs most often in young adult men, with a peak incidence between the ages of 15 and 30 years. The scaphoid is less susceptible to fracture during the phase when it is mostly cartilaginous, thus making scaphoid fracture rare in childhood. In this article, we review current treatment of fracture of the scaphoid and examine controversial topics in its management.

Adolescent↗

Displaced fractures of the scaphoid.

The scaphoid is the most commonly fractured carpal bone. The displaced fracture poses a particular surgical problem. While scaphoid fractures as a group show a 90%-95% union rate, those fractures with greater than 1 mm of displacement are associated with a 55% incidence of nonunion and a 50% rate of avascular necrosis. Displaced fractures that unite spontaneously do so only after prolonged immobilization and are associated with a greater incidence of painful malunion. Displaced scaphoid fractures that result in malunion or nonunion are more prone to develop late carpal osteoarthritis. The higher incidence of complications with the displaced scaphoid fracture suggests that an anatomic reduction is essential. If closed manipulation is unsuccessful, open reduction and internal fixation are indicated.

Adult↗

Central placement of the screw in simulated fractures of the scaphoid waist: a biomechanical study.

BACKGROUND: Recent reports on internal fixation of acute fractures of the scaphoid waist have demonstrated higher rates of central placement of the screw when cannulated screws were used than when noncannulated screws were used. This cadaveric study was designed to determine whether central placement in the proximal fragment of the scaphoid offers a biomechanical advantage. METHODS: Eleven matched pairs of scaphoids were removed from fresh cadaveric wrists. Each scaphoid was placed in a custom manufactured jig that was used to create reproducible central and eccentric positioning of the guidewire. Then a linear osteotomy was made followed by placement of a Herbert-Whipple cannulated screw to fix the osteotomy. The specimen was then potted in a holder with use of polymethylmethacrylate with a Kirschner wire passed through the proximal end of the scaphoid and placed into a fixture with a pneumatically driven plunger resting on the surface of the distal pole. The load acting through the plunger was measured with use of a load-cell, and its excursion was measured with use of a linear variable differential transformer. Stiffness, load at 2 mm of displacement, load at failure, and mechanism of failure were measured, and the two groups were compared with regard to stiffness and strength. RESULTS: Central placement of the screw in the proximal fragment of the scaphoid had superior results compared with those after eccentric positioning of the screw. Fixation with central placement of the screw demonstrated 43% greater stiffness (12.7 N per mm compared with 8.9 N per mm; p < 0.01), 113% greater load at 2 mm of displacement (126 N compared with 59.1 N; p < 0.01), and 39% greater load at failure (712 N compared with 513 N; p > 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: Central placement of the screw in the proximal fragment of the scaphoid offers a biomechanical advantage in the internal fixation of an osteotomy of the scaphoid waist. Clinical efforts and techniques that facilitate central placement of the screw in the fixation of fractures of the scaphoid waist should be encouraged.

Biomechanical Phenomena↗

A modified technique of four-bone fusion for advanced carpal collapse (SLAC/SNAC wrist).

This study reports the outcome of 16 patients treated with a modified four-bone fusion for symptomatic stage II and III advanced carpal collapse. The technique is based on fusion of the capitate, lunate, hamate and triquetrum using an autogenous corticocancellous bone-graft fixed with screws. The void left behind after scaphoid excision was filled with an extensor carpi radialis longus anchovy. After an average follow up of 3 years; there were 13 excellent and three good outcomes. In every patient pain relief was achieved with preservation of joint motion and grip strength. All the patients were able to return to their previous activities and jobs. Radiographic evaluation showed bone fusion in all 16 patients with a slight decrease in carpal height but a well preserved radiolunate joint space. In conclusion, this technique provides immediate stable fixation and early mobilization and assures bone fusion.

Adult↗

Scaphoid nonunion: diagnosis and treatment.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Understand the anatomy and pathophysiology of scaphoid fractures. 2. Understand the risk factors for scaphoid nonunion. 3. Identify treatment options for scaphoid nonunion and their respective advantages and disadvantages. 4. Identify salvage procedures for scaphoid nonunion advanced collapse of the wrist. Scaphoid nonunion is a common but difficult problem for hand surgeons. The diagnosis of scaphoid nonunion is often delayed, and therefore, treatment must be tailored to the type of fracture, the duration of nonunion, and the presence or absence of resulting arthritis. This article reviews the diagnosis and work-up of scaphoid nonunion, classification schemes for scaphoid nonunion, and various treatment options, including internal fixation, nonvascularized and vascularized bone grafting, and salvage procedures.

Arthrodesis↗

Scaphoid fractures and scaphoid nonunion. Diagnosis and treatment.

Scaphoid nonunion can cause pain, loss of wrist motion, and loss of grip strength. Because initial roentgenograms are not always definitive, patients suspected of having a scaphoid fracture despite negative initial radiographs should undergo bone scan. Treatment of acute nondisplaced fracture of the scaphoid generally nonoperative, involving immobilization in a cast. Treatment of scaphoid nonunion is generally operative, and many procedures and their associated risks are reviewed. There is no consensus about the clinical implications of scaphoid malunion.

Adolescent↗

Increased radiodensity of the proximal pole of the scaphoid: a common finding in computed tomography imaging of the wrist.

OBJECTIVES: To determine whether the proximal pole (PP) of the scaphoid is denser than the distal pole (DP) in a diverse population of patients undergoing computed tomography (CT) imaging of the wrist. METHODS: Sixty-nine patients who had CT of the wrist were retrospective reviewed. We measured CT density of the medullary bone of PP and DP of the scaphoid and calculated PP/DP ratio. To evaluate the variability of PP/DP ratio, we compared the ratios of these 3 groups. These patients were separated into 3 groups based on their diagnoses: group 1, healed scaphoids treated by casting; group 2, scaphoid nonunions; group 3, intact scaphoids. RESULTS: Proximal pole was denser than DP in most subjects. Proximal pole/distal pole ratio was similar among groups (P < 0.05). Fracture healing, sex, and age did not affect this ratio. However, we did not study scaphoids with avascular necrosis. CONCLUSIONS: Proximal pole was denser than DP in most of our subjects, including those with intact scaphoids, healing scaphoid fractures, and nonunions.

Adult↗

Does three-dimensional computer simulation improve results of scaphoid nonunion surgery?

The purpose of this study was to clarify the effectiveness of the three-dimensional computer simulations in scaphoid nonunion surgery. Seven consecutive clinical patients with scaphoid nonunion at the middle third comprised the study group. Surface models of the scaphoid were constructed on the computer using computed tomography data of the bilateral wrists in neutral position. The distal and proximal fragments of the nonunion model were matched to the mirror image of the contralateral scaphoid model. The rotation of the distal fragment relative to the proximal fragment was calculated, and reduction of the displaced fragment of the scaphoid nonunion was simulated. Similarly, the estimated bone defect and the appropriate site and direction of the screw insertion were simulated. Full-sized hard models of the bone, including a model with simulated reduction and screw insertion, then were made using stereolithography based on the computer data. In the actual surgery, reduction, bone grafting, and screw insertion were achieved using the hard models as guides. All the patients obtained solid bone fusion and substantial clinical improvement with normalized scapholunate and radiolunate angles after surgery. Three-dimensional computer simulations were found as useful for accurate correction of scaphoid nonunions and proper screw placement, which consequently leads to good clinical results.

Adolescent↗

X-ray diagnosis of acute scaphoid fractures.

In a retrospective review of the radiographs taken for 113 acute scaphoid fractures, each view was assessed for the clarity of demonstration of the fracture. The X-rays on which diagnosis of fracture were made, were taken between 0 and 16 days after injury (mean, 2 days). Whenever a lateral, supinated oblique or elongated view was taken, the fracture was always seen clearly on an alternative view. We recommend the use of four views at initial presentation of suspected scaphoid fracture: PA and lateral to assess carpal alignment, with pronated oblique and ulnar deviated PA to detect the fracture.

Acute Disease↗

Scaphoid nonunions. Pitfalls and pearls.

Our ability to treat scaphoid nonunions has improved dramatically. The degree of collapse and bone loss can be accurately assessed in waist fractures using sagittal images on CT scans. These nonunions require reduction and bone grafting to re-establish the normal geometry of the scaphoid. Magnetic resonance imaging helps evaluate whether or not avascular necrosis is present in the proximal pole. Because of the poor prognosis of conventional bone grafts, a vascularized bone graft is recommended as the primary treatment when AVN is present. The volar collapse of the humpback deformity is best corrected with a volar approach and the proximal pole nonunion is best approached using a dorsal approach. Nearly all proximal pole nonunions require a vascularized bone graft and all acute proximal pole fractures require open reduction and internal fixation. Using specially designed cannulated screws, the nonunions can be stabilized accurately to decrease the time to resolution of the nonunion and minimize the amount of time in a cast. Stable fixation requires that the screw fixation target the central portion of the scaphoid regardless of the type of screw design used. Using these techniques, the hand surgeon should be able to provide a reasonable prognosis for patients presenting with a scaphoid nonunion, and the treatment should result in functional range of motion, grip strength, and relief of pain.

Bone Screws↗

Is intrasound vibration useful in the diagnosis of occult scaphoid fractures?

This study was designed to confirm the results of Finkenberg et al. (J Hand Surg 1993;18A: 4-7), who found a high sensitivity (100%) and specificity (95%) of the intrasound vibration method in diagnosing occult scaphoid fractures. These occult scaphoid fractures are not visible on x-ray films, but clinically the patients are suspected of having a scaphoid fracture. A vibratory apparatus is placed over the anatomical snuff-box and a vibration of 100 mW is emitted; a painful sensation is produced if the scaphoid is fractured. Thirty-seven consecutive patients with a clinically suspected scaphoid fracture were evaluated. In 6 patients, a scaphoid fracture was radiographically identified; in the remaining 31 patients, a 3-phase bone scan was obtained. Eleven wrists showed increased uptake over the scaphoid and were considered to have an occult scaphoid fracture. In this group, bone scintigraphy was used as the reference standard. The vibration test was painful in 1 of 6 patients with a proven scaphoid fracture and in 3 of the 11 patients with a positive bone scan. In contrast to the results of Finkenberg et al, the intrasound vibration method shows a sensitivity of 24%, a specificity of 85%, a positive predictive value of 40%, and a negative predictive value of 65%. We conclude that the accuracy of intrasound vibration is low and that it is not useful in the diagnosis of scaphoid fractures.

Adolescent↗

The radial portal for scaphotrapeziotrapezoid arthroscopy.

The scaphotrapeziotrapezoidal (STT) joint is a complex joint in which the arthroscope and instruments can be used through the radial midcarpal and STT-ulnar portals. This report describes a new arthroscopic portal at the STT joint to complete and improve the evaluation and treatment of this joint by arthroscopy: The STT-radial (STT-R) portal is situated immediately radial to the abductor pollicis longus at the STT level. Five cadaveric wrist specimens were dissected immediately after the portal was established, and photographed to determine the proximity of neurovascular structures. Magnetic resonance imaging evaluation of 15 hands was performed to measure the proximity of the radial artery. A cadaveric distal scaphoid excision was also created arthroscopically to show the real usefulness of this portal. Results of the anatomic study showed that no lesions of nerves or vessels were seen at this portal. Magnetic resonance imaging showed that the radial artery was located at a safe distance from the portal. The distal scaphoid excision was performed 15 minutes after the STT portals were established. Our results suggest that this new portal is safe and effective.

Anthropometry↗

Dorsal approach to scaphoid nonunion.

The surgical approach for treatment of scaphoid nonunion usually involves various combinations of screws and Kirschner wires, with or without bone grafts. This article reports our results with 36 dorsal-approach bone grafting procedures for treatment of scaphoid nonunion with Kirschner wires. Union was achieved in 89%. The average follow-up was 5 years. Flexion/extension averaged 76% of the opposite wrist, and grip strength was 88% of the opposite hand. Ninety-one percent of the employed patients returned to their original jobs. The dorsal approach provides satisfactory exposure for fragment reduction and bone grafting.

Activities of Daily Living↗

Bone malalignment in acute injuries of the wrist.

The purpose of this study was to analyze radiographic signs of carpal bone instability in patients with an acutely injured wrist. There were 80 patients (52 women and 28 men) with a fall on the outstretched hand. Fifty patients had a fracture of the distal radius, and eight had a scaphoid fracture. The patients with a bone fracture showed a larger scapholunate angle than those without a fracture (P less than 0.001, t-test). However, only four of them showed true carpal bone instability: two patients with a scaphoid fracture and one with a radius fracture had dorsiflexion instability of the wrist and one patient with a radius fracture had dorsal subluxation of the wrist. In addition, one patient without any bone fracture had scapholunate dissociation, one form of carpal bone instability. Although carpal bone instability is not frequent in an acutely injured wrist, its signs should be remembered in the radiographic analysis of the traumatic wrist to prevent subsequent articular disorders.

Acute Disease↗

[Aseptic necroses of the carpal bones].

The most frequent aseptic necrosis in the carpal area is Kienböck's disease, followed by necrosis of the scaphoid and capitate. Necrosis of carpal bones are seen after different conditions as chronic traumatism, cerebral palsy, chemotherapy, as well as deficient vascularisation of the carpus. Varietys of the wrist joint anatomy may contribute to development of Kienböck's disease. The natural course of the disease shows progressive necrosis and bone destruction in adults. However the clinical symptomatology may show a higher degree of variation. Prevention of carpal dissociation seems to be important. Early surgery by vascularisation techniques and retention of the necrotic bone are indicated. In stages III and IV with collapsing deformity, resection-interposition arthroplasty using autologous material, or silastic spacers, have proven to be successful.

Arthrodesis↗

Partial union of acute scaphoid fractures.

Sixty-six patients with acute scaphoid fractures were treated non-operatively in a below elbow plaster for 8 to 12 weeks and underwent CT scans along the longitudinal axis of the scaphoid at 12 to 18 weeks. These scans showed that 14 fractures had not united and that 30 had united throughout the whole cross-section of the scaphoid. The other 22 had partially united with bridging trabeculae in some areas of the cross-section. These 22 partial unions were graded as 0% to 24% union (0 cases), 25% to 49% union (5 cases), 50% to 74% union (7 cases), and 75% to 99% union (10 cases). The 12 patients who had less than 75% fracture union were followed-up further and nine underwent another CT scan at 23 to 40 weeks after the initial injury. These showed union across the whole of the cross-section of the fracture in seven cases and 75% to 99% union in the other two cases, who had full and painless wrist function. We conclude that partial union of the scaphoid is a common occurrence but, in most cases, it progresses to full union without the need for prolonged plaster immobilization.

Adult↗

[Therapy for static scapholunate instability -- reconstruction of the dorsal part of the scapholunate ligament with a periosteal flap of the iliac crest].

Recurrent instability is frequent following capsulodesis, tenodesis, or ligament reconstruction in static scapholunate instability. Therefore a periosteal flap of the iliac crest was designed to reconstruct the dorsal part of the SL ligament, which is known to be the biomechanically strongest portion and also the axis of rotation between the scaphoid and lunate. Biomechanical testing of ten fresh frozen dorsal SL ligaments and ten periosteal flaps of the iliac crest showed similar properties concerning failure force, failure displacement, failure stress, energy to failure and stiffness. Results of eight specimens in each group were available following successful testing. Failure force of the dorsal SL ligament was 171.8 N (SD 44.2), energy to failure amounted 269.1 N-mm (SD 98.9), failure stress was 10.3 N/mm (2) (SD 1.3), failure displacement 2.9 mm (SD 0.4), and stiffness 77.2 N/mm (SD 21.4). Testing of the periosteal flap gave the following values: failure force 144.3 N (SD 38.7), energy to failure 217.9 N-mm (SD 85.0), failure stress 9.9 N/mm (2) (SD 1.7), failure displacement 3.0 mm (SD 0.4) and stiffness 60.5 N/mm (SD 14.7). In addition to these test values, clinical and radiological data of eleven patients were available following reconstruction of the dorsal SL ligament with a periosteal flap of the iliac crest. The interval between trauma and surgery was 15 months, mean follow-up was 29 months. One patient was free of pain, whereas ten mentioned pain during or following strenuous work. Two patients were completely satisfied, nine complained about some restriction during special activities. Active range of motion amounted to 56 degrees extension, 46 degrees flexion, 17 degrees radial abduction, 30 degrees ulnar abduction. Grip strength was 38.5 kg, which was 79 % of the contralateral side. Radiological evaluation demonstrated a correction of the static instability in nine cases. In two patients recurrence of static instability was obvious. The prerequisite for success of the procedure is the easy reduction of the carpals. In cases of a fixed rotatory subluxation of the scaphoid, the technique cannot maintain the reduction.

Adult↗