(This review can be also viewed by opening the attached PDF file)

The paper addresses an important problem of the design of orthopaedic implants to to
ensure that they fit the maximum of the target population. The Authors build statistical
shape model of a tibia and use to optimise the implant position. They also conduct
modelling analysis (FE method is used) biomechanical performance of bone-implant
construct. The methodology appears to be original and technically sound. However, some
aspects (bone-to-bone and bone-to-implant interactions) of the modelling conduct require
further clarification. Therefore, my opinion is that before the paper can be regarded as
ready for publication/presentation in the Workshop, the Authors should answer the
questions given below and modify the paper following them.

Major comments
1) Biomechanical FE Simulations: How were the interactions between two split (as a
result of fracture) bone parts and between the bones and implant modelled?
The Authors write that “3D beam elements were used to fix implant to the bone”
and that “Attachment of the beam to the bone was preformed using an embedded
element technique”. However, in order for such modelling of attachment to be
meaningful, the implant should be allowed to move/slide in relation to the bone. This
would require application of contact interface (or similar type of constrain) between
the implant and bone, and between two split bone parts. The paper does not mention
existence of any type of such interface between the bone and implant and between
two split bone parts.

2) What finite element solver was used and what type of finite element analysis (i.e.
geometrically linear or non-linear) was applied?

3) Legend of Table 1 (p. 8): Was the bone-implant distance determined using imagebased
methods described in Sections 2-4?

Minor comments
1) P. 2 reference [Rueckert] is missing in the Reference list

2) P. 2, figure 1 caption. Is: “axis”, should be: “axes” (plural)

3) P. 3, second column, second paragraph. Is: “the fracture should be a continuous”,
should be: “the fracture should be continuous”

4) P. 4, last sentence. Is “in Eq. 3”, should be: “in Eq. 4”.