Abstract
Introduction
Cement pressurisation in the distal humerus is technically difficult due to the anatomy of the humeral intramedullary (IM) cavity. Conventional cement restrictors often migrate proximally or leak, reducing the effect of pressurisation during implantation. Theoretically with a better cement bone interdigitation, the longevity of the elbow replacement can be improved. The aim of this cadaveric study was to evaluate the usefulness of a novel technique for cementation.
Method
Eight paired fresh frozen cadaveric elbows were randomly allocated to conventional cementing techniques or cementing using a paediatric foley catheter as a temporary restrictor. The traditional cementing technique consisted of canal preparation using irrigation, brushing and drying prior to cementation, with no use of a cement restrictor. The new technique involved same canal preparation but prior to cementation a size 8 foley catheter was introduced and the balloon inflated to act as a temporary cement restrictor. The humeri were cut into 10mm sections. Each slice was photographed and radiographed. This dual imaging technique was used to establish the best methodology for evaluation of cement penetration. Cement penetration was calculated as a ratio of the area of intra-medullary cavity occupied by the cement.
Results
There was no significant difference between the photographic and radiographic method of measuring cement penetration. Cement penetration was significantly better in the foley catheter group (P = 0.002-0.037). The maximum penetration was observed in the most distal 2-5cm.
Conclusion
The foley catheter technique consistently and significantly achieved a better cement interdigitation into the cancellous bone, without leaving a void in the cement. This study has demonstrated a new cementing technique for elbow arthroplasty, utilising a paediatric foley catheter as a temporary humeral intra-medullary plug, increasing cement pressurisation and restricting proximal cement migration. Future studies using this methodology will not require supplementation of photographs with radiographic analysis.
