A Randomised Multi-centre Study to Compare the Short-term Outcomes of Minimally Invasive and Conventional Surgery in Primary Total Hip Replacement

• Number of hours post-operatively after which subjects are first able to mobilise with a frame or crutches [ Time Frame: First post-operative day ] [ Designated as safety issue: No ]
• Level of assistance required to perform 3 functional tasks (supine to sit, sit to stand and bed to chair transfer)on the second post-operative day [ Time Frame: Second post-operative day ] [ Designated as safety issue: No ]
• Time taken (in seconds) for subjects to walk 10 metres on the second post-operative day. [ Time Frame: Second post-operative day ] [ Designated as safety issue: No ]
• Amount of time (in seconds) for which subjects are able to stand on the operative leg on the second post-operative day. [ Time Frame: Second post-operative day ] [ Designated as safety issue: No ]

• Haematological parameters assessed over a 56 hours post op [ Time Frame: 56 hours post-operatively ] [ Designated as safety issue: No ]
• Pain levels and wound condition [ Time Frame: Until discharge ] [ Designated as safety issue: No ]
• Trendelenberg sign [ Time Frame: Until discharge ] [ Designated as safety issue: No ]
• Day of discharge [ Time Frame: Until discharge ] [ Designated as safety issue: No ]
• Activity levels over specified distances [ Time Frame: Until discharge ] [ Designated as safety issue: No ]
• Harris Hip score [ Time Frame: Annually ] [ Designated as safety issue: No ]
• Oxford Hip score [ Time Frame: Annually ] [ Designated as safety issue: No ]
• Radiological analysis [ Time Frame: 6weeks, 6mths, 1yr, 2yrs, 5yrs and 10yrs post-surgery ] [ Designated as safety issue: No ]

The purpose of this study is to compare the short-term outcomes of two surgical techniques, minimally invasive and conventional, when used in the treatment of patients with hip joint disease requiring a total hip replacement. Patients who enter the study will be randomly allocated to undergo surgery using the minimally invasive or conventional surgical technique and will be evaluated at regular intervals following hip surgery using patient, clinical and x-ray assessments with a focus on short term rehabilitation.

• Procedure: DePuy MI System
  A minimally invasive surgical technique used in total hip replacement.
• Procedure: Conventional surgical technique
  A conventional surgical technique used in total hip replacement

• Active Comparator: 1
  DePuy MI System
  Intervention: Procedure: DePuy MI System
• Active Comparator: 2
  Conventional surgical technique
  Intervention: Procedure: Conventional surgical technique

Inclusion Criteria:

i) Male or female subjects, aged between 18 and 75 years inclusive.

ii) Subjects who are able to give voluntary, written informed consent to participate in this investigation and from whom consent has been obtained.

iii) Subjects who in the opinion of the Investigator, are able to understand this investigation, co-operate with the investigational procedures and are willing to return to the hospital for all the required post-operative follow-ups.

iv) Subjects with a primary diagnosis of osteoarthritis.

v) Subjects considered suitable for a primary total hip arthroplasty and are considered suitable for a minimally invasive surgical procedure.

Exclusion Criteria:

i) Subjects who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up in this study, or extend their time to discharge beyond that required for their hip replacement surgery.

ii) Women who are pregnant.

iii) Subjects who are known drug or alcohol abusers or with psychological disorders that could effect follow-up care or treatment outcomes.

iv) Subjects who have participated in a clinical study with an investigational product in the last 6 month(s).

v) Subjects who are currently involved in any injury litigation claims.

vi) Subjects with a Body Mass Index (BMI) > 30.

vii) Subjects with a malunion, arthrodesis or severe dysplasia with superior femoral head migration.

viii) Subjects requiring a simultaneous bilateral total hip arthroplasty.

ix) Subjects undergoing the second stage of a staged bilateral who are less than 9 months post-arthroplasty