1 Scaphoid fracture location determines management

The scaphoid is the cornerstone of the wrist, providing the key link between the proximal and distal rows of carpal bones.

Scaphoid fracture is the most common carpal fracture, accounting for 60 per cent of all carpal fractures.

It normally occurs in sporty young people between 15 and 25 due to a fall on the outstretched hand causing wrist hyperextension (Duckworth et al 2012).

The location of the fracture is the main factor in determining scaphoid fracture management.

There is a high risk of poor outcomes such as non-union, malunion, scaphoid non-union advanced collapse and avascular necrosis, particularly with displaced waist fractures, bicortical fractures and proximal pole fractures.

Eighty per cent of the surface of the scaphoid is covered with articular cartilage, leaving only small areas of real estate for vascular supply.

The main vascular supply is through radial artery branches that enter via the dorsal ridge and travel in a retrograde direction towards the proximal pole.

Avascular necrosis is a complication of waist and particularly proximal pole scaphoid fractures following disruption of this vascular supply.

The distal pole receives its vascular supply from radial artery branches that enter directly into the palmar aspect at the distal tubercle, leading to uneventful fracture healing in almost all cases (Gelberman & Menon 1980).

2 Early diagnosis of scaphoid fracture helps avoid complications

Radial-sided wrist pain following a fall on the outstretched hand is a familiar presentation and only four to 20 per cent of those presenting to a hospital emergency department with radial-sided wrist pain will have a scaphoid fracture (Duckworth et al 2012).

Missed or delayed diagnosis is a significant contributing factor to complications.

The initial investigation is always via X-ray, which has a sensitivity to detect a scaphoid fracture of no more than 70 per cent (Gäbler et al 2001).

The recommended views are posteroanterior, lateral and a Stecher’s projection (closed fist and ulnar deviation for extension of the scaphoid).

Twenty to 30 per cent of scaphoid fractures can be described as occult—a fracture is present but not showing up on X-ray (Buijze & Jupiter 2018).

Where the patient history is commensurate with a suspected scaphoid fracture and there is a negative X-ray finding, an MRI is recommended within three to five days.

MRI is the best form of secondary imaging, with 99 per cent sensitivity and the added capacity to demonstrate soft tissue injuries (Buijze & Jupiter 2018).

CT is also acceptable as a secondary imaging option, with the benefit of the clearest images of the fracture fragments.

This is particularly helpful if stability is in question or surgery is being planned (Gilley et al 2018).

3 Determining instability is crucial for scaphoid fracture treatment

Two-thirds of scaphoid fractures are located at the waist and of those, 60–85 per cent are non-displaced or minimally displaced (Garala et al 2016).

Treatment for these fractures is a short arm, non-removable fibreglass or plaster cast with a neutral wrist position and the thumb out for six weeks (Buijze et al 2014), followed by a suitable period of graduated rehabilitation.

There is a moderate level of evidence in favour of a non-removable cast over a removable, custom-made thermoplastic orthosis such as one made by a hand therapist (Buijze & Jupiter 2018).

An off-the-shelf wrist splint is inadequate.

Simple algorithms are available for scaphoid fractures of the proximal pole, waist and distal pole (Clementson et al 2020).

These algorithms are based on the Mayo classification system for scaphoid fractures according to fracture location.

It includes an appendix that outlines factors contributing to instability (Benoudina et al 2015, Cooney et al 1980).

Almost all proximal pole fractures and unstable scaphoid fracture patterns at any location require surgery, while almost all distal pole fractures are managed in a cast.

Defining instability is complex. Factors include displacement greater than one millimetre, dorsal intercalated segment instability, comminution, perilunate injury and bicortical fractures (Clementson et al 2020).

4 Persistent pain may indicate delayed scaphoid union

Bony union is assessed primarily through clinical assessment. Where persistent pain over the fracture site is present, a CT scan is performed.

Union of a scaphoid fracture on CT scan is defined as having trabeculae across 50 per cent of the fracture line (Clementson et al 2015).

Persistent pain may also represent an associated scapholunate ligament injury.

It is worth noting that anatomical snuffbox tenderness may be present for years following a united scaphoid fracture (Clementson et al 2017).

In cases of delayed union, cast treatment is extended for further blocks of four weeks to a maximum of 12–14 weeks, at which stage surgery may be required (Clementson et al 2015).

5 Scaphoid rehabilitation is graduated and tailored

Rehabilitation following removal of the cast lasts for a period of six to 12 weeks, depending on the functional requirements of the patient.

The goal is to achieve near full active range of motion, strength, power and endurance and nil or minimal tenderness on palpation of the anatomical snuffbox.

For example, people returning to gymnastics, combat sports, weightlifting, AFL or rugby require a full program of power and endurance training including plyometrics and falls training.

Those returning to ball sports, tennis or athletics don’t need to do plyometrics before a return to sport.

Advanced power work can be commenced at consolidation, which is twice the timeframe it has taken to achieve union.

Consideration is given to possible concurrent injuries. For example, the scapholunate ligament is injured in 25 per cent of scaphoid waist fractures (Jørgsholm et al 2010).

Graduated rehabilitation would then exclude gripping exercises and early weight-bearing.

Return to work for those performing administrative work or work with low physical demands may commence almost immediately following the cast application.

Manual workers return to work when union has been achieved and range of motion and grip strength are within 20–40 per cent of the contralateral side (Fowler & Hughes 2015).

Return rates and return times to sport are high and low respectively for both surgically and conservatively managed scaphoid fractures, with surgical management rates slightly better in both cases.

The return rate to sport for conservatively managed is 90 per cent and surgically managed 98 per cent.

The time to return to sport for conservatively managed is 9.6 weeks and surgically managed 7.3 weeks (Goffin et al 2019).

>>Karen Fitt APAM is a physiotherapist, an accredited hand therapist (as awarded by the Australian Hand Therapy Association) and a past president of the Australian Hand Therapy Association. Karen is the CEO of Hand Faculty: Hand Therapy Education.

Figures 1, 2 and 3 from Clementson 2020, used with permission

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Course of Interest:

Masterclass in unusual stress fracture presentation—Dr Henry Wajswelner