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.

• Hip Arthroplasty (Procedure), also known as G7 acetabular cup system,, Echo Bimetric Full profile stem, Neutral liner, Arcom XL, Neutral liner, E1, Ceramic liner, Monobloc Ceramic Biolox Delta Head, 32 mm, Cobolt chrome head, 32 mm, porous coated (PPS) titanium alloy shells: Hip Arthroplasty comparing 3 different bearings.

Primary outcomes

• Difference in osteolytic volume at 5 years postoperatively measured by CT scan. [5 years]: CT scan will be performed on 240 of the 360 patients post operatively and at 5 years follow up

Secondary outcomes

• Hip specific clinical outcome in patients who received the one of the above mentioned combinations of total hip systems. [3 months, 1,2,5,7 and 10 year follow up]: Oxford Hip score (OHS) will be collected from all the patients preoperative and at all follow up visits.
• Implant positioning [Immediately postoperative,1,2,5,7 and 10 year follow up]: Implant positioning will be measured using Martell method .
• Subjective satisfaction [3 months, 1,2,5,7 and 10 year follow up]: Subjective satisfaction will be collected using Numerical Rating Scale (NRS) and will be collected preoperative and at all follow ups.
• Safety and survivorship [Continously throughout the study until 10 years FU]: Adverse Events will be reported including revisions at any post-operative time points
• Squeaking evaluation [3 months, 1,2,5,7,10 years]: Evaluation of noise from the hip will be made at all follow up visits by a noise assessment form
• Pain Assessment [3 months, 1,2,5,7,10 years]: Pain will be collected using Numerical Rating Scale (NRS) and will be collected preoperative and at all follow ups.
• Health related quality of life [3 months, 1,2,5,7,10 years]: EQ5D (Health related quality of life questionnaire from Euro Qol) will be collected from all the patients preoperative and at all follow up visits.
• Physical activity level [3 months, 1,2,5,7,10 years]: UCLA (University California Los Angeles activity questionnaire) will be collected from all the patients preoperative and at all follow up visits.
• Hip specific clinical patient outcome measure [3 months, 1,2,5,7,10 years]: Harris Hip score (HHS)will be collected from all the patients preoperative and at all follow up visits.

Sex: All, ages: 18 Years to 75 Years, accepts healthy volunteers

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.

• Anders Troelsen, MD, PhD, Principal investigator, Hvidovre University Hospital
• Henrik Malchau, MD, PhD, Principal investigator, Sahlgrenska University Hospital
• Ville Remes, MD, PhD, Principal investigator, Jokilaakson Terveys Oy