Evaluation of the Trabecular Metal™ Revision Hip Cup Using Bone Mineral Density (DEXA)

Evaluation of the Trabecular Metal™ Acetabular Revision Cup Using Dual-Energy X-ray Absorptiometry (DEXA)

In 1997, the FDA approved the use of Trabecular Metal™ (Zimmer, Trabecular Metal Technology, Inc., Parsippany, NJ) for acetabular cups, a porous tantalum structural biomaterial that was developed to address the limitations of other implant materials, with the potential to improve implant fixation.

Porous tantalum (80% porosity) offers potentially greater ingrowth and bone graft incorporation, believed to be restricted by the low porosity of other commonly used implants (30%). Additionally, the low modulus of elasticity property (3 MPa) of porous tantalum provides more normal physiological loading conditions which theoretically reduce stress shielding and resultant bone loss surrounding the implant. These properties are much desired advantages for implants used in cementless THA.

Various porous tantalum implants have shown favorable clinical results. Unger et al. reported excellent bone graft incorporation of the acetabular component based on serial radiograph data at a minimum 1-year follow-up.

Dual-energy X-ray absorptiometry (DEXA) is a well-established method for detecting periprosthetic bone mass changes around the femoral and acetabular THA components.

The primary objective of this study is to quantify and compare periprosthetic bone mineral density (BMD) changes in THA revision patients receiving Trabecular Metal™ and metal-backed acetabular components, measured using DEXA scanning techniques. Additionally, this study will analyze and compare clinical outcomes of these patients, based on SF-12v2 and HOOS.

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Inclusion Criteria:

• Age: 18 - 85 years
• Sex: Both male and female will be included. The male-to-female ratio will depend upon the patient population.
• Stable Health: At the time of surgery based on physical examination and medical history.
• Patient is a revision total hip recipient, which requires a metal-backed hemispherical cup.
• Patient or patient's legal representative has signed the Informed Consent form. The patient is capable of making informed decisions regarding his/her healthcare.

Exclusion Criteria:

• Patients undergoing bilateral surgery or had prior hip arthroplasty on contralateral side less than 6 months from date of surgery.
• Patients who do not plan to return to a Cleveland Clinic surgeon for follow-up visits (i.e. out of state/country patients who may choose to follow-up with a different surgeon).
• Patients with history of radiation therapy.
• Patients with known diagnosis of Brooker grade 3 or 4 HO (heterotopic ossification) in the hip joint region.
• Patients with known diagnosis of renal disease.
• Patients with known diagnosis of osteoporosis.
• Patients with history of steroid use in the hip joint region.
• Patients that have had a previous lumbar fusion.
• Patients whose surgical reconstruction required a pelvic cage or plate.
• Patient was a poor compliance risk - treated for ethanol or drug abuse, physical or mental handicap, etc.
• Any female of childbearing potential who is pregnant or is planning on becoming pregnant during the study period (~2 years postoperative).