Table 1 Inclusion and exclusion criteria

• Trauma patients with surgically treated (peri)- or intra-articular fractures of the lower extremities, i.e. pelvic fractures, acetabular fractures, distal femur fractures, tibia plateau fractures, pilon fractures and foot fractures. According to the AO fracture classification type A, B, or C.

• Age > = 18 years

• Being able to understand the questionnaires and measurement instructions

• Restricted mobility due to other causes than the surgically treated (peri)- or intra-articular fracture, i.e. bilateral fractures, amputations, or ipsilateral significant fractures that hamper mobilization.

• Severe non-fracture-related comorbidity of the lower extremity, e.g. congenital bone and tissue disorders.

• No additional problem of rheumatic orthopaedic or neurological nature of the lower extremities (e.g. primary coxarthrosis or gonarthrosis)

• Congenital bone and tissue disorders.

• No informed consent