Distal femoral fracture during primary total knee arthroplasty.

Abstract

To review 6 cases of periprosthetic distal femoral fracture during total knee arthroplasty (TKA). Of 778 women and 691 men who underwent primary TKAs using posterior-stabilised (n=1240), cruciate-retaining (n=165), or semiconstrained (n=64) implant, 5 women and one man with a mean age of 73.3 years and a mean body mass index of 31.6 kg/m(2) sustained an intra-operative periprosthetic distal femoral fracture and were followed up for a mean of 12.8 (range, 2-39) months. Respectively in patients with a posterior-stabilised, cruciate-retaining, or semi-constrained implant, the intra-operative fracture rates were 0.32%, 0%, and 3.13%. For women, the respective rates were 0.46%, 0%, and 5.10%. Intra-operative fracture was 9.69 times (p=0.03) more likely to occur in patients with a semi-constrained implant than those with a posterior-stabilised implant, and was 4.44 times (p=0.22) more likely to occur in women than in men. Half of the fractures occurred during the trial phase when the tibia was reduced onto the femur, and half during final prosthesis implantation. Distal femoral fracture during primary TKA is rare and associated with the use of a semiconstrained implant. Preserving as much bone in the distal femur is advised.