Background
Intraoperative humeral shaft fracture is a possible complication during revision shoulder arthroplasty when removing cement.1 Drilling to disrupt the cement mantle followed by cement removal is an established technique but it can lead to cortical perforation and fracture. We describe a simple technique to minimise these risks during drilling.
Technique
After removal of the existing humeral stem, a 2ml syringe with the plunger removed and the end cut off is wedged into the proximal cement mantle in line with the humeral canal. Drilling of the distal mantle is performed through the syringe with reassurance that the drill will be guided down the canal rather than towards the humeral cortex (Figs 1 and 2). The inner diameter of a 2ml syringe easily accommodates a drill up to 6.5mm in size.
Figure 1.
Intraoperative use of the technique with syringe guiding the drill down the centre of the humeral shaft
Figure 2.
2ml syringe allowing easy passage of a drill bit up to 6.5mm in size
Discussion
Free hand drilling during revision arthroplasty can allow the drill to follow an eccentric path, leading to fracture as the drill bit bounces of the distorted metaphyseal bone and existing cement mantle. Use of the syringe maintains the drill along a path through the centre of the cement mantle and away from the cortical bone (Fig 3). This technique is only reliable when the existing stem has been placed centrally in the humeral canal as seen on the preoperative x-ray. When the existing stem is placed eccentrically, use of this technique will direct the drill towards the cortex, causing perforation. It is also more appropriate in the humerus than the femur as the humerus has a straighter medullary canal.2
Figure 3.
Depiction of effect of using syringe to guide drill rather than using drill freehand
References
- 1.Athwal GS, Sperling JW, Rispoli DM, Cofield RH. Periprosthetic humeral fractures during shoulder arthroplasty. J Bone Joint Surg Am 2009; 91: 594–603. [DOI] [PubMed] [Google Scholar]
- 2.Descamps S, Moreel P, Garcier JM et al. Existence of a rotational axial component in the human humeral medullary canal. Surg Radiol Anat 2009; 31: 579–583. [DOI] [PubMed] [Google Scholar]