Purpose. To review records of 17 patients who sustained a tibial or femoral intra-operative fracture during primary cemented total knee arthroplasty (TKA) Methods. Records of 1346 primary cemented TKAs using the NexGen LPS fluted tibial component performed by a single surgeon were reviewed. 12 tibial and 5 femoral intra-operative fractures occurred in 5 men and 12 women aged 54 to 83 (mean, 71.6) years. No patient had any condition that may predispose to osteoporosis. Results. All 12 tibial fractures occurred during hammering down of the final tibial component. They were vertical crack fractures of the anterior cortex of the medial tibial plateau with minimal displacement and did not extend beyond the tip of the tibial stem. Four of the 5 femoral fractures were avulsion fractures in the coronal plane of the medial femoral condyles and occurred during removal of the intercondylar notch. The remaining femoral fracture involved the Intra-operative fracture in posterior-stabilised total knee arthroplasty