Inclusion Criteria:

• Individuals with a severely painful and/or disabling hip joint with osteoarthritis, traumatic arthritis or developmental dysplasia of the hip or avascular necrosis of the femoral head.
• In order to take part in this study, all study participants must be between the ages of 18 and 75 years of age, at the time of surgery.
• Scheduled for a primary total hip replacement.

Exclusion Criteria:

• Active infection
• Pregnancy
• Mental illness where the known condition is likely to compromise the patient's ability to consent, affect the patient's assessment of their progress or complete the 10 year cycle of follow-up appointments and reviews
• Grossly distorted anatomy (surgeon's discretion)
• Osteomalacia where uncemented implant fixation is contraindicated
• Active rheumatoid arthritis.
• Osteoporosis
• Metabolic disorders which may impair bone formation where uncemented implant fixation is contraindicated
• Muscular atrophy or neuromuscular disease
• Allergy to implant material
• Any patient who cannot or will not provide informed consent for participation in the study
• Those whose prospects for a recovery to independent mobility would be compromised by known coexistent, medical problems