A 3-Arm Study on G7 Acetabular Cup With Echo BiMetric Stem in Total Hip Arthroplasty

DESIGN: Prospective 3 Arm Randomized controlled trial.

PURPOSE:To compare three commonly used contemporary bearings in Total Hip Arthroplasty (THA). In addition, to evaluate the safety and effectiveness of the G7 Cups and Echo BiMetric Stem in THA.

OUTCOME MEASURES: Osteolysis, clinical outcomes, patient satisfaction, intraoperative/surgical data, implant positioning, survivor ship, and adverse events.

POPULATION: 360 hips (240 will have CT scan for analysis of osteolysis).

ELIGIBILITY: Patients who meet inclusion and exclusion criteria defined in this protocol.

DURATION: All patients will be followed at 3 months, 1, 2, 5, 7 and 10 year postoperatively. Assuming the enrollment will be completed 18 months. The total study duration will be 11.5 years.

STUDY GROUPS/TREATMENTS

Group 1 - G7 Metal-on-Polyethylene (MoP) (Arcom XL) + Echo BiMetric Group 2 - G7 Metal-on-Polyethylene (MoP) (E1) + Echo BiMetric Group 3 - G7 Ceramic-on-Ceramic (CoC) + Echo BiMetric The study's primary efficacy endpoint will include the difference in osteolytic volume at 5 years postoperatively measured by Computertomografi (CT) scan.

Inclusion criteria

Patient is 18 to 75 years of age, inclusive.

• Patients determined to be suitable for uncemented fixation by investigator
• Patient is skeletally mature.
• Patient qualifies for primary unilateral total hip arthroplasty (THA) based on physical exam and medical history including the following:

• Osteoarthritis (OA)
• Developmental Dysplasia without subluxation
• Patient is willing and able to provide written informed consent.
• Patient is willing and able to cooperate in the required post-operative therapy.
• Patient is willing and able to complete scheduled follow-up evaluations as described in the Informed Consent.

Exclusion criteria

The patient is:

• A prisoner
• Mentally incompetent or unable to understand what participation in the study entails
• A known alcohol or drug abuser
• Anticipated to be non-compliant.

• The patient has a neuromuscular disorder, vascular disorder or other conditions that could contribute to prosthesis instability, prosthesis fixation failure, or complications in postoperative care.
• The patient has a neurologic condition in the ipsilateral or contralateral limb which affects lower limb function.
• The patient has a diagnosed systemic disease that could affect his/her safety or the study outcome.
• The patient is known to be pregnant.
• The patient is unwilling or unable to give informed consent, or to comply with the follow-up program.
• The patient has an active or latent infection in or about the affected hip joint or an infection distant from the hip joint that may spread to the hip hematogenously.

The patient has had previous Girdlestone procedure (resection arthroplasty) or surgical fusion of the hip to be operated.

• The patient has insufficient bone stock to fix the component. Insufficient bone stock exists (ex: Dorr type C) in the presence of metabolic bone disease (i.e. osteoporosis), cancer, and radiation.
• Estimated cup size smaller than 48 or stem size smaller than 7
• The patient has known local bone tumors in the operative hip.