HS7: HOW I MANAGE SCAPHOID NON UNION

Abstract

Introduction: Scaphoid non union probably occurs more frequently than we realise. That means that a significant ‘unknown’ population with this condition exists – people who carry on with life with some restrictions, but not enough to seek help. This wide variety of ‘expression’ of the symptoms needs to be borne in mind when considering how best to manage each patient.

Diagnosis: Diagnosis is often obvious. In most cases, plain radiographs are all that are necessary to make the diagnosis confidently. However, whilst radiographs will usually tell you if the scaphoid is healed or not, they will not give you any reliable information on vascularity of the fragments. MRI with contrast is needed to confidently describe the vascularity status, and so give the patient an accurate prognosis for surgery. In cases where union/non union is uncertain, CT will provide unequivocal information if the scan slices are orientated correctly.

I routinely request MRI with contrast before bone graft surgery so that I can give the patient an idea of the likely success of that surgery beforehand.

Decision making: Surgery is not always the best option for patients. Some patients have functioned perfectly well for many years with an un-united scaphoid, and the condition may only have come to light after a moderate re-injury. It is reasonable, in these cases, to treat with an expectant period of splintage. A number of these patients will become comfortable again – although still have an un-united scaphoid. You then have an opportunity to discuss the risks/benefits in a calmer atmosphere. When a recent scaphoid fracture (proven) has progressed to non union, I will always discuss grafting in some detail with each patient. This option is best employed when no degenerative changes have appeared, and therefore recent fractures (younger than 3–5 years) would be considered for grafting. If the non-union is older or of indeterminate age, care should be taken before recommending grafting. Indeed, a ‘successful’ bone grafting of an established and mature non-union with associated degenerative changes is likely to make the patient’s symptoms worse. Remember, one of the main reasons for recommending bone grafting is to reduce the risk of early degenerative disease (SNAC). If degenerative disease is already present, the main indication for grafting is no longer present. There are other surgical alternatives to bone grafting. These will be discussed under their broad categories of ‘motion preserving’ and ‘motion eliminating’ procedures.

Bone grafting: A choice exists between non-vascular-ised and vascularised bone grafting. Traditionally, graft has been harvested from the iliac crest, although, in my own Day Surgery practice, this is no longer possible for operational reasons.

This enforced restriction means that all my bone grafts now come from the distal radius. There is good evidence to support the use of graft from this site – especially in the younger male. As a result, I developed the technique of employing vascularised grafts for all my scaphoid non-unions. Not necessarily because I thought they were any better, but because they were straightforward to perform, offered no disadvantages, and may actually offer an advantage.

I favour the palmar grafts described by Mathoulin because of the biomechanics of the humpback deformity. Scaphoid waist non unions need a palmar wedge to restore their length and shape. Using a corticocancellous palmar wedge graft from the distal radius provides this.

Proximal pole non unions do demand a different approach (both surgically and in decision making). The Zaidemberg dorsal graft is usually more appropriate for these cases, but I recommend developing skills in both techniques to use the right graft for the right indication.

I will illustrate the surgical and rehabilitation techniques I employ in some detail, and discuss the results of these treatments in my personal series.

Salvage: No discussion about ‘management’ of scaphoid non union would be complete without some mention of salvage. However, salvage (in my opinion) is more than just dealing with a failed bone graft. ‘Salvage’ refers to the rescue of whatever function is available and appropriate for each patient. In some cases, I would recommend a plan that some people may regard as ‘salvage’ if it best suited an individual patient.

I will illustrate and justify the salvage techniques I consider in scaphoid non union.