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wrist injury, wrist injury treatment, scaphoid fracture, scaphoid fracture diagnosis, scaphoid fracture treatment, rehabilitation

Wrist injury - scaphoid fractures: the diagnosis, treatment and management of scaphoid fractures in athletes

The Sports Injury Doctor

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The summer of 2002 was all about the metatarsal – of David Beckham, in case you've forgotten. (You can read all about it, his toe, that is, in SIB, issue 23, last October.) This summer another of his small bones grabbed the headlines – the scaphoid. Mr Beckham and company were in South Africa when during a friendly against the home nation, yet another tackle made on the England captain resulted in an awkward landing and a wrist injury.

Surprisingly, the media frenzy was not as fervent, misleading or prolonged as last summer, but this time there was no World Cup round the corner. Nevertheless, David Beckham's misfortune has provided us with an opportunity to outline the numerous problems and pitfalls associated with scaphoid fractures, from presentation through to treatment options and rehabilitation. This article aims to provide an overview of current scaphoid fracture management options with particular reference to the younger patient.

Anatomy & biomechanics
The scaphoid is one of eight carpal bones which lie in two rows. They are articulated together to form a semicircle, the convexity of which is proximal and articulates with the forearm bones. The scaphoid occupies the most radial position (thumb side) in the proximal row.

It is a boat-shaped bone, which articulates directly with the radius proximally and is a critical link in the mechanism of the carpus. It is commonly divided into four distinct parts: the proximal pole, the waist, the distal body and the tuberosity. It is a key bone to both wrist motion and stability.

A complex series of interosseous ligaments exists between the scaphoid and other carpal bones: the scapholunate ligament appears to be the primary stabiliser between the scaphoid and lunate and the radioscaphocapitate and scaphotrapezial ligaments are secondary stabilisers(2).

The blood supply of the scaphoid arises from the radial artery entering the scaphoid at or distal to its waist along the dorsal ridge. This accounts for up to 80% of the entire blood supply and as much as 100% of the supply to the proximal pole. Therefore fractures through the waist and proximal third render the more proximal fragment of the scaphoid at risk of avascular necrosis (AVN) or death.

Because of its offset proximal and distal articular surfaces, the scaphoid has a natural tendency to palmar-flex with longitudinal loading. Hence, extension of the scaphoid places progressively increasing tension on the palmar cortex of the curved waist of the scaphoid. Excessive extension or ulnar deviation of the wrist, coupled with excessive loading, mechanically predisposes the scaphoid to fracture, especially if the strong ligaments attaching to it retain their integrity(12).

The problem
The scaphoid is the most common carpal bone injured. Fractures of the scaphoid lead to significant physical and economic morbidity. They are commonly seen in young athletes where immobilisation in a cast will lead to a prolonged period away from sporting activities.

There is much written in the literature about the scaphoid. This includes descriptions about the complex three-dimensional anatomy of the scaphoid, mechanisms of injury, methods of fixation and whether the current management of scaphoid fractures should include early fixation.

Presentation
This frequently follows a fall on an outstretched hand with resulting pain and swelling in the radial side of the wrist. With particular reference to athletes, contact sports often yield higher rates of this type of injury. The exact mechanism is described above.

Initial suspicion may be of a distal radial fracture; but if no radial fracture is seen on the preliminary wrist X-rays, then a scaphoid fracture must be suspected. Most painful wrists are seen in the accident and emergency department where patients are often assessed by inexperienced doctors. It is important to take a clear and accurate history although this can be difficult. The age and sex of the patient must be taken into account along with the mechanism of injury. Often the painful wrist is examined without comparison to the other side. Many individuals experience pain in the anatomical snuffbox when the superficial radial nerve is compressed.

There is much in the literature on how the accurate diagnosis of a scaphoid fracture can be made. These range from the combination of clinical signs, eg evaluating tenderness in the anatomical snuffbox and over the scaphoid tubercle, pain on longitudinal compression of the thumb and range of thumb movement(8).

When these clinical signs were used in combination, within the first 24 hours following injury they produced 100% sensitivity and specificity of 74%. Failure to diagnose scaphoid fractures, which can be well treated acutely may result in delayed or non-union (with subsequent osteoarthritis) and deformity at a later date.

Imaging
Due to the complex anatomy of the scaphoid, at least four views on plain X-ray are required to show the bone adequately (scaphoid views). These can still be difficult to interpret and consequently some fractures are missed. Moreover, some 'non-fractures' have plaster immobilisation applied. Therefore, much work has been carried out assessing the different imaging modalities available to improve the sensitivity and specificity of diagnosing scaphoid fractures.

Scaphoid views are performed first and if no fracture is seen but highly suspected, the patient is commonly placed in a scaphoid cast (Colles type cast with thumb spica) and asked to return a week to 10 days later for a follow-up X-ray. The fracture is often diagnosed at this juncture when the X-rays are more likely to show a fracture line but inevitably a proportion are still not evident – missed or true negatives. Reliability on clinical suspicion may be utilised and a plaster cast is applied for a further six weeks or another modality of imaging requested to confirm the diagnosis. This is an unacceptable period of immobilisation for the athlete with a true negative and thus studies have focused on determining alternative diagnostic tools to be used acutely (at the time of presentation) or at the first follow-up visit after an initial negative X-ray.

The use of modified carpal box radiography (mX-CB) in the detection of scaphoid fractures was investigated by Toth et al recently(14). Ninety per cent of the fractures were diagnosed by mX-CB and only 6.8% needed referral to CT. Sensitivity of mX-CB at initial presentation was 81.6% and interobserver agreement very high, suggesting that mX-CB be used as a primary and an early follow-up investigation to yield high diagnostic accuracy and low referral rate to a more expensive diagnostic tool, such as CT.

Certainly, the evidence would suggest that plain films and an adjunct such as mX-CB, used together if necessary, in the acute setting, would provide the diagnostic sensitivity required. However, if the diagnosis cannot be established by clinical and simple radiographic means, bone scans have been recommended in the literature and preferred over CT or MRI, for expense reasons.

The sensitivity of MRI has been examined most recently(3). Patients with normal scaphoid radiographs but a suspicion of scaphoid fracture were referred for MRI of the wrist. All scans were performed within 14 days of injury. Out of 195 patients scanned, 19% had a scaphoid fracture, 19% had other wrist/carpal fractures and 62% had no fracture. More importantly, the management of 92% of patients was altered as result of the MRI scan, leading the authors to claim that MRI allows an early definitive diagnosis to be made and should be regarded as the gold-standard investigation in this population. MRI also has the advantage of being the best investigation to determine avascular necrosis, in the longer term, while CT has an established role in detecting non-unions.
To summarise, all patients should have plain radiographs. If a fracture is evident, treatment options may be considered. If no fracture is evident, but highly suspected, additional investigations should be arranged and a plaster cast applied in the interim. MRI appears to be the gold-standard investigation, but a CT or bone scan may be more readily obtained and is more economical. Other forms of radiography such as mX-CB may be considered at the initial presentation and may be helpful in determining the diagnosis, but the understanding and ability to perform and interpret these specialised X-rays is of importance and hence they may be of little use if not carried out and seen regularly. We recommend that athletes with normal initial radiographs be referred for an MRI scan so that a prompt accurate diagnosis is made.

Classification
Two methods of classifying scaphoid fractures are recognised. Russe in 1960 described the fractures in three types, based on the relationship of the fracture line to the long axis of the scaphoid: transverse, vertical oblique and horizontal oblique. Herbert and Fisher in 1984 classified scaphoid fractures more broadly, as unstable or stable; stable fractures including crack fractures and tuberosity fractures; unstable fractures including distal third, proximal pole and displaced waist fractures, as well as fractures associated with carpal dislocation and communited fractures.

Differential diagnosis

Any fracture around the scaphoid can cause pain and swelling in the anatomical snuffbox. Ligamentous and other soft tissue injuries can also cause similar symptoms.

Scaphoid fracture treatment options
Once the diagnosis of a fracture has been established, several treatment options may be considered with reference to the fracture pattern.

The great majority of scaphoid fractures occur in young men who may be involved in athletic activity. As previously mentioned, conservative treatment can be prolonged, and early fixation could afford the opportunity of early mobilisation and an earlier return to full function. Avoiding plaster immobilisation in these patients helps to decrease the risks of muscle atrophy, osteopenia, articular cartilage degeneration or ligament fibrosis(15, 16). This is particularly important in some contact sports which do not allow the use of playing splints; a scaphoid fracture in such circumstances may mean a whole season away from high-level activities.

Apart from being suitable for undisplaced fractures only, the period of cast immobilsation can be prolonged. Riester et al used silastic casts or padded plasters in the acute treatment of scaphoid fractures in athletes(10). Their management depended on early treatment, close attention to cast fitting and the fact that the fractures were stable from low-velocity trauma. Nevertheless, patients required immobilisation for six months.

Rettig, Weidenbener and Gloyeske reported similar union rates for athletes treated with acute fixation or with playing casts(9). They felt that these athletes were not at risk of non-union secondary to participation in sports. Radiographic outcomes and clinical function were equivalent to those cases treated more conservatively. Sporting individuals and athletes who are in sports where playing casts are not allowed cannot afford the possibility of plaster immobilisation for 10-30 weeks.

The end point of treatment must be the same as for other fractures, ie, radiographic and clinical union, to allow full function and prevent post-traumatic arthrosis. In athletes, however, it is necessary to ensure a rapid return to participation in sports. For an undisplaced scaphoid fracture the average union rate is approximately 90% with a healing time of 9-12 weeks. Acute fixation, therefore, may allow for a rapid recovery and return to sports. Two main surgical options exist: open reduction and internal fixation and closed reduction and percutaneous fixation. For displaced or unstable fractures these are the treatments of choice.

The necessity for open reduction and internal fixation of the displaced scaphoid fracture has been recognised for many years. Hirsch suggested open reduction and internal fixation for intraarticular fracture of the scaphoid in 1914. However he advised total expiration of the bone. There are several methods available for open reduction and internal fixation of the scaphoid. These include the Herbert screw, cannulated screws, Kirschner wires, the blade plate and percutaneous screws. There is much literature on these methods of open reduction and internal fixation and suggestions as to when it is appropriate to use these methods of fixation.

Possible problems
The potential disadvantages of open fixation include post-operative stiffness, infection and long term sequelae such as scapho-trapezial arthrosis. An aggressive approach to undisplaced or minimally displaced scaphoid fractures in athletes has been limited by the morbidity of open surgery. The open procedure for fixation of the scaphoid is associated with extensive soft tissue stripping and damage to the anterior radio-carpal ligament(4). Infection and scar pain in particular are also significant post-operative problems(1), whilst reflex sympathetic dystrophy may be catastrophic.

Percutaneous fixation following closed reduction was first reported by Streli in 1970 in the German literature(13). Early reservations were, however, expressed after poor preliminary results. Since, numerous studies have shown good results for various types of percutaneous fixation methods(6, 7 ,11, 13, 17); Haddad & Goddard(5) treated 50 patients with the Acutrak screw, allowing mobilisation immediately post-operatively. Union was achieved in all cases after an average of 55 days and range of movement at the time of union was equal to that of the contralateral side at three months. Patients returned to sedentary work within four days and to manual work/sports within five weeks. Early scaphoid internal fixation avoids the dilemma of when to discontinue cast immobilisation. However, scaphoid fixation is undoubtedly a technically demanding procedure which requires a degree of practice. Percutaneous fixation seems most suited to undisplaced or minimally displaced fractures that are easily reduced closed.

To summarise
The recommended treatment for unstable scaphoid fractures is open reduction and internal fixation. Closed reduction and percutaneous fixation (screw or pin) can be considered in minimally displaced or reducible fractures, whereas open reduction is recommended for all other displaced fractures. Early mobilisation of stable fractures after internal fixation is advocated with the use of a playing splint after athletic injuries.

We are reliably informed that David Beckham underwent surgical fixation of his scaphoid fracture; whether an open or percutaneous technique was utilised is uncertain. The plaster cast applied seems to be in keeping with a 'belt and braces' approach and seems sensible if media coverage of his recent publicity trip to Japan is an accurate indication of the mobbing and manhandling he is subject to on his travels, which may become even more feverish in Madrid, when he starts with his new club. It remains to be seen whether David Beckham's scaphoid fracture heals satisfactorily, and over what time period. What may be of more concern to him, is what lies in store for him at Real Madrid and how often his scaphoid will be tested on the pitch!

Rahul Patel and Fares Haddad

References
(1) Barton NJ. 'The Herbert screw for fractures of the scaphoid.' J.Bone Joint Surg. (Br), 1996;78:517-8.
(2) Berger RA. 'The anatomy of the scaphoid.' Hand Clinics 2001; 17:525-532.
(3) Brydie A, Raby N. 'Early MRI in the management of clinical scaphoid fracture.' Br.J.Radiol. 2003;76:296-300.
(4) Garcia-Elias M, Vall A, Salo JM, Lluch AL. 'Carpal alignment after different surgical approaches to the scaphoid: a comparative study.' J.Hand Surg. (Am.) 1988;13:604-12.
(5) Haddad FS, Goddard NJ. 'Acute percutaneous scaphoid fixation. A pilot study.' J.Bone Joint Surg. (Br.) 1998;80:95-9.
(6) Inoue G, Shionoya K. 'Herbert screw fixation by limited access for acute fractures of the scaphoid.' J.Bone Joint Surg. (Br.) 1997;79:418-21.
(7) Ledoux P, Chahidi N, Moermans JP, Kinnen L. [Percutaneous Herbert screw osteosynthesis of the scaphoid bone.] Acta Orthop.Belg. 1995;61:43-7.
(8) Parvizi J, Wayman J, Kelly P, Moran CG. 'Combining the clinical signs improves diagnosis of scaphoid fractures. A prospective study with follow-up.' J.Hand Surg. (Br.) 1998; 23:324-7.
(9) Rettig AC, Weidenbener EJ, Gloyeske R. 'Alternative management of midthird scaphoid fractures in the athlete.' Am.J.Sports Med. 1994;22: 711-4.
(10) Riester JN, Baker BE, Mosher JF, Lowe D. 'A review of scaphoid fracture healing in competitive athletes.' Am.J.Sports Med. 1985;13:159-61.
(11) Schwarz N. [Results of percutaneous screw-fixation of fresh scaphoid-fractures (author's transl).] Unfallheilkunde. 1981;84:302-6.
(12) Short WH, Werner FW, Green JK, Masaoka S. 'Biomechanical evaluation of ligamentous stabilizers of the scaphoid and lunate.' J.Hand Surg. (Am.) 2002;27:991-1002.
(13) Streli R. [Percutaneous screwing of the navicular bone of the hand with a compression drill screw (a new method).] Zentralbl.Chir 1970;95:1060-78.
(14) Toth F, Mester S, Cseh G, Bener A, Nyarady J, Lovasz G. 'Modified carpal box technique in the diagnosis of suspected scaphoid fractures.' Acta Radiol. 2003;44:319-25.
(15) Whipple TL. 'The role of arthroscopy in the treatment of wrist injuries in the athlete.' Clin.Sports Med. 1992;11:227-38.
(16) Whipple TL. 'Stabilization of the fractured scaphoid under arthroscopic control.' Orthop.Clin. North Am. 1995;26:749-54.
(17) Wozasek GE, Moser KD. 'Percutaneous screw fixation for fractures of the scaphoid.' J.Bone Joint Surg. (Br) 1991;73:138-42.

wrist injury, wrist injury treatment, scaphoid fracture, scaphoid fracture diagnosis, scaphoid fracture treatment, rehabilitation

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