Retrograde nailing for supracondylar fracture around total knee replacement: a compatibility study using the Trigen supracondylar nail.

The incidence of periprosthetic supracondylar femoral fractures around total knee arthroplasties (TKRs) is increasing. An acceptable treatment is to insert a supracondylar nail, but not all TKRs will permit this. An unofficial table of compatibilities is available from Smith and Nephew, but this has not been peer reviewed. We ascertained the ten most common TKR prostheses currently used in the United Kingdom from the National Joint Registry (NJR) Report published in September 2005. We used samples of each prosthesis with a saw bone model and checked their compatibility for accepting a Trigen supracondylar nail. We present the dimensions of the intercondylar notches of the top ten TKR prostheses and our reference chart demonstrates which of these are suitable for use with supracondylar nails. We have found that the notch position, rather than the notch size, was the most important factor in determining nail compatibility. Most of the TKRs commonly used in the UK will allow supracondylar nailing for fixation of periprosthetic fractures. There are, however, notable exceptions and our chart provides a quick and easy reference for knee surgeons involved in these cases.