The ‘Unsolved Fracture'...Now that sounds like a challenge...

OPINION: Brian Thornes

24/01/2012

Intracapsular hip fractures have been dubbed the ‘unsolved’ fracture for almost a century.¹

There is a 40% re-operation rate with internal fixation, reported in a Cochrane Review. This is due to:

1. Non-union 
2. Avascular necrosis
3. Poor femoral head fixation (‘cut-out’)

This has lead to the use of hemi- and total hip arthroplasty to circumvent these problems, though may just substitute a different set of short and long-term problems. In a perfect world, perfect reduction and fixation may reduce or obviate the need for hip fracture arthroplasty.

Going back to first principles, to create the optimum environment requires:

1. Perfect anatomical reduction
2. Strong, secure femoral head fixation
3. No rotational forces whatsoever, but allow fracture compression

Perfect reduction requires surgical expertise, and should always be achievable, though sometimes requiring an open reduction.

With the above always achievable, we move on to fixation. The strongest fixation devices in my local hardware store are expanding bolts. The solution thus may come from adaptation of such industrial devices, perfected for ease of surgical use and the clinical environment.

The first issue is the expansion mechanism; it cannot disrupt the fracture reduction, push, pull or rotate the femoral head. Therefore it needs to deploy radially outwards, perpendicular to the axis of the device. Mechanically a scissors-jack works in this fashion, with threads of opposite directions compressing a hinged limb from both ends that will lever upwards. Thus the X-Bolt was conceived.

The second issue is reversibility. The X-Bolt can easily be reversed by counter-rotation of the inner drive screw to retract the expandable limbs.

The third and final issue is preventing rotation. The keyed plate barrel here comes to the rescue. This ensures no rotational forces are transmitted to the reduction or femoral head, either during deployment, or whilst dynamic fracture compression occurs.

A critical look at all historical intracapsular hip fracture failures due to non-union or ‘cut-out’, will inevitably have unwanted femoral head rotation as a major factor.

Will the X-Bolt generation solve the unsolved fracture? It ticks all the boxes, including usability and cost.  Clinical use and time will tell...      

Reference:

1. DICKSON, J. A. The” Unsolved” Fracture. J Bone Joint Surg 1953; 35-A, 805.

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