Selecting the Right Hip Prosthesis for Young Patients

The overall purpose of this study is to show whether the Primoris® hip prosthesis results in a smaller loss of bone density than standard hip prosthesis, which in the longer term may result in an improved survival of prosthesis No. 2 after revision / replacement of a Primoris® hip prosthesis.

The primary outcome is periprosthetic bone quality in Primoris® hip prosthesis compared to standard hip prosthesis measured by DXA scanning.

The secondary outcomes are to assess:

• The hip function measured by gait analysis.
• Hip strength at pressure gauge.
• Prosthetic migration / migration measured by radio-stereometric analysis (RSA).
• Patient satisfaction measured by PROMs.

Inclusion criteria

Women ≤ 45 years or men ≤ 55 years with hip osteoarthritis, suitable for hip prosthesis.

Patients who wish to participate in the project and give written consent after oral and written information.

Exclusion criteria

• Patients with previous bone disease, metabolic disease, including diabetes, or the use of drugs that affect bone density.
• Smoking more than 20 cigarettes daily
• Patients with fracture in the femur or acetabulum.
• Patients who do not understand the given patient information
• Competing disorder requiring treatment with antiinflammatory drugs (NSAIDs, steroid, cytostatics).
• Estimated residual life <10 years
• Rheumatoid arthritis or other arthritis (eg psoriasis arthritis).
• Previous surgery on the relevant hip joint.
• Co-Morbidity (ASA Group 3-5).
• Neurological disorder that compromises motor skills and rehabilitation.
• Pregnancy.
• Osteoarthritis secondary to mb. Calvé-Legg-Perthes / Avascular Caput Necrosis, Epiphysiolysis Capitis Femoris and Multiple Epiphysic Dysplasia.
• Acetabular dysplasia with secondary subluxation (Crowe grade II to IV).
• Previously detected osteoporosis or osteoporosis detected by current DXA scanning.
• Ongoing treatment with osteoporosis medicine (bisphosphonates, estrogen receptor modulators and parathyroid hormone, etc.).
• Aseptic caput necrosis (posttraumatic, idiopathic).
• Varus or valgus deformity in proximal femur (collum angle <125 ° or> 145 °.)
• Collum femoris assessed too retro- or anteverted.