Around 4% of total knee arthroplasties (TKA) are revised 15 years after the primary operation, most due to loosening of the implant. The use of uncemented prostheses are expected to extend the fixation time and thereby the years of TKA survival. When a cementless implant is inserted, direct bone ingrowth to the implant depends on a complete primary stabilisation. Movement between the bone and implant will cause a fibrous membrane leading to micromotions. Micromotions can be evaluated by radiophotogrammetric analysis (RSA) in early follow-up and they have been shown to be a prognostic marker for painful loosening of the implant.