MAYO HIP PROSTHESIS

K943230 · Mayo Clinic · LPH · Jan 14, 1997 · Orthopedic

Device Facts

• Record ID: K943230
• Device Name: MAYO HIP PROSTHESIS
• Applicant: Mayo Clinic
• Product Code: LPH · Orthopedic
• Decision Date: Jan 14, 1997
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 888.3358
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

The MAYO Hip is used in total hip arthroplasty, a surgical procedure restricted to patients with substantial pain or marked functional disabilities in which conservative treatment has not provided acceptable relief and who are not candidates for other less aggressive forms of surgery. This hip is indicated for noncemented use in skeletally mature individuals. Diagnostic indications include severe hip pain and disability due to rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral head, slipped capital femoral epiphysis, fused hip, fracture of the pelvis, and diastrophic variant.

Device Story

MAYO Hip Prosthesis is a short-stemmed, press-fit modular femoral component for total hip arthroplasty. Device replaces hip joint by implanting into femur; femoral stem mates with femoral head via Morse-type taper; head articulates against UHMWPE acetabular liner. Designed for conservative bone preservation; features collarless, dual-tapered body with short distal stem for rotary fixation. Immediate fixation achieved via three-point metaphyseal contact; secondary fixation via biological ingrowth into proximal fiber metal pads. Used by orthopedic surgeons in hospital settings. Conservative design minimizes femoral neck resection, bone preparation, and stress shielding; eliminates intramedullary fixation to reduce thigh pain, blood loss, and foreign body exposure. Preserves bone stock for potential future revisions.

Clinical Evidence

Eight years of clinical research provided. Study demonstrates satisfactory clinical outcomes. Results show statistically significant reduction in surgical blood loss and post-operative pain compared to BIAS Hip prostheses. Non-clinical evidence includes Finite Element Analysis (FEA), fatigue testing, porous coating characterization, and galvanic corrosion assessment.

Technological Characteristics

Modular femoral component; materials: Tivanium alloy and commercially pure titanium fiber pads. Design: collarless, dual-tapered (double wedge) body, short distal stem. Fixation: uncemented, press-fit, proximal three-point metaphyseal fixation, biological ingrowth via fiber metal pads. Connection: Morse-type taper for femoral head attachment. No software or electronic components.

Indications for Use

Indicated for skeletally mature individuals requiring total hip arthroplasty due to severe hip pain and disability from rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis, slipped capital femoral epiphysis, fused hip, pelvic fracture, or diastrophic variant, where conservative treatment failed.

Regulatory Classification

Identification

A hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis is a device intended to be implanted to replace a hip joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across the joint. This generic type of device has a femoral component made of a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy or a titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high molecular weight polyethylene articulating bearing surface fixed in a metal shell made of Co-Cr-Mo or Ti-6Al-4V. The femoral stem and acetabular shell have a porous coating made of, in the case of Co-Cr-Mo substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average pore size between 100 and 1,000 microns, interconnecting porosity, and a porous coating thickness between 500 and 1,500 microns. The generic type of device has a design to achieve biological fixation to bone without the use of bone cement.

Predicate Devices

• Zimmer Anatomic Hip System
• HG MultiLock Hip Prosthesis
• BIAS Total Hip System

Submission Summary (Full Text)

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JAN 14 1997

# Mayo Clinic

K943230

200 First Street Southwest Rochester, Minnesota 55905 Telephone [phone]

Bernard F. Morrey, M.D.
Chair
Department of Orthopedic Surgery

MAYO ® Hip Prosthesis
Summary of Safety and Effectiveness

- Submitted By:
B. F. Morrey, M.D.
Mayo Clinic
200 First Street Southwest
Rochester, Minnesota 55905

- Device Trade Name
MAYO ® Hip Prosthesis

- Device Classification Name
Hip joint metal/polymer/metal semi-constrained porous uncemented prosthesis

- Predicate Devices
Zimmer ® Anatomic Hip System
HG MultiLock™ Hip Prosthesis
BIAS™ Total Hip System

- Device Description
The MAYO Hip Prosthesis is a short-stemmed, press-fit modular femoral component developed by Bernard F. Morrey, M.D., of the Mayo Clinic and is intended to be implanted into the human femur to replace a hip joint. The MAYO Hip incorporates several technological features of the Zimmer Anatomic Hip Prosthesis (and other predicate devices) such as the Morse-type tapered neck and fiber metal pads for bone ingrowth, and is made from the same materials (titanium alloy and commercially pure titanium) as the predicate devices. The femoral stem is collarless, has a dual taper (double wedge) body, and has a short distal stem (tail). The femoral stem is available in four sizes each of which can be utilized in the left or right hip.

The modular femoral stem is designed to mate with a femoral head through a Morse-type taper. The femoral head in turn articulates upon the UHMWPE liner of an acetabular component. The MAYO Hip Prosthesis meets the criteria of the generic device described in 21 CFR 888.3358.

The MAYO Hip supports a conservative approach to total hip arthroplasty by allowing for minimal femoral neck resection, minimal bone preparation, minimal stress shielding, absence of intramedullary fixation, reduction in blood loss, and potential for ease of revision.

The short distal portion of the stem is used to assist in proper placement of the stem and provides for rotary fixation. Immediate fixation is

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achieved through three-point (anteroposterior and lateral planes) fixation in the metaphyseal bone of the proximal femur. The stem does not rely upon intramedullary fixation, therefore the source of thigh pain is eliminated. Surgery time is reduced because the femoral medullary canal is not reamed or violated. This results in statistically significant less blood loss than that of a conventional, uncemented primary total hip arthroplasty. Additionally, reduction in the amount of metal (due to the short distal stem and double wedge shape) results in less exposure of a foreign body to the intramedullary canal. The conservative femoral neck resection, which preserves bone stock, will facilitate subsequent procedures should a revision of the hip be required.

- Intended use:

The MAYO Hip is used in total hip arthroplasty, a surgical procedure restricted to patients with substantial pain or marked functional disabilities in which conservative treatment has not provided acceptable relief and who are not candidates for other less aggressive forms of surgery. This hip is indicated for noncemented use in skeletally mature individuals. Diagnostic indications include severe hip pain and disability due to rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral head, slipped capital femoral epiphysis, fused hip, fracture of the pelvis, and diastrophic variant.

- Comparison to Predicate Device

The MAYO Hip Prosthesis is substantially equivalent to the hip prostheses listed above as predicate devices. Each is designed as a femoral component that is intended to be implanted into the human femur to replace a hip joint. Each femoral component is manufactured from Tivanium Alloy and commercially pure titanium fiber pads which are metallurgically bonded to the proximal body of the stem. All are designed to be used without bone cement. Primary fixation is achieved by press fit. The predicate devices rely upon intramedullary fixation through the presence of a long distal stem while the MAYO Hip utilizes a shorter, more conservative, wedge shaped stem to achieve immediate three-point proximal femoral fixation. Secondary fixation is achieved through biological ingrowth into the fiber metal pads. Each femoral component uses a socket and Morse-type taper joint for attaching the femoral head to the stem.

- Clinical and Nonclinical Data

Performance data are available and include Finite Element Analysis (FEA), fatigue testing, characterization of the porous coating, information that addresses the potential for galvanic corrosion, and eight years of clinical research that indicates a satisfactory clinical outcome. Clinical data also reveal a statistically significant reduction in blood loss during surgery and a statistically significant reduction in pain as compared to the BIAS Hip prostheses. These performance data validate the claim of substantial equivalence and provide evidence of safety and effectiveness.

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