C2 A-TAPER ACETABULAR SYSTEM

P050009 · Biomet, Inc. · MRA · Dec 16, 2005 · Orthopedic

Device Facts

• Record ID: P050009
• Device Name: C2 A-TAPER ACETABULAR SYSTEM
• Applicant: Biomet, Inc.
• Product Code: MRA · Orthopedic
• Decision Date: Dec 16, 2005
• Decision: APWD
• Device Class: Class 3
• Attributes: Therapeutic

Intended Use

The C²a-Taper™ Acetabular System is indicated for use in primary total hip arthroplasty in skeletally mature patients with non-inflammatory degenerative joint disease such as osteoarthritis, avascular necrosis, congenital hip dysplasia, and post-traumatic arthritis.

Device Story

Ceramic-on-ceramic hip articulating system; consists of aluminum oxide ceramic femoral heads and acetabular liners. Intended for use with titanium alloy acetabular shells and femoral stems (12/14 taper). Used in total hip arthroplasty by orthopedic surgeons in clinical settings. Ceramic components articulate to provide bearing surface; titanium shells/stems provide fixation to bone. System aims to reduce wear debris compared to traditional metal-on-polyethylene bearings. Clinical outcomes predicted via reference to TRANSCEND Ceramic Hip System (P010001) due to identical articulating components. Benefits include improved joint function and pain relief for patients with degenerative hip disease.

Clinical Evidence

Referenced clinical data from P010001: prospective, multi-center, historical control trial of 959 procedures in 848 patients. Primary endpoints: survivorship, Harris Hip Score (HHS), and radiographic assessment at 2 years. Results: Mean HHS improved from 45.1 pre-op to 94.8 (original population) at 2 years. Cumulative survivorship at 24 months was 98.76%. Complication rates included 1.1% revision/removal rate. Bench testing demonstrated no detectable wear after 5 million cycles.

Technological Characteristics

Ceramic-on-ceramic bearing system. Components: Aluminum oxide ceramic (ASTM F603, ISO 6474) femoral heads and liners. Titanium alloy (Ti-6Al-4V) acetabular shells and femoral stems with plasma-sprayed porous coating (ASTM F1580). 12/14 taper interface. Modular design with varying neck lengths and shell diameters. No software or electronic components.

Indications for Use

Indicated for primary total hip arthroplasty in skeletally mature patients with non-inflammatory degenerative joint disease (osteoarthritis, avascular necrosis, congenital hip dysplasia, post-traumatic arthritis). Contraindicated in patients with local/distant infection, skeletal immaturity, osteoporosis, metabolic bone disorders, osteomalacia, rapid joint destruction/bone loss, vascular insufficiency, muscular atrophy, or neuromuscular disease.

Reference Devices

• TRANSCEND Ceramic Hip System (P010001)

Submission Summary (Full Text)

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# SUMMARY OF SAFETY AND EFFECTIVENESS

## I. GENERAL INFORMATION

| Device Generic Name: | Total Hip System,
Ceramic Articulation |
| --- | --- |
| Device Trade Name: | C²a-Taper™ Acetabular System |
| Applicant’s name and address: | Biomet Manufacturing Corporation
56 East Bell Drive
P.O. Box 587
Warsaw, Indiana 46582 US |
| Premarket Approval (PMA) Number: | P050009 |
| Date of Panel Recommendation: | None |
| Date of Notice of Approval to the Applicant: | December 16, 2005 |

The approval of Biomet’s C²a-Taper™ Acetabular System is being granted in part due to a licensing agreement with the CeramTec, who owns the rights to the PMA for the TRANSCEND Ceramic Hip System (P010001) and also distributes the ceramic components used in both the C²a-Taper™ and TRANSCEND Systems. The C²a-Taper™ Acetabular System uses the same ceramic heads and ceramic liners as the TRANSCEND System and uses Biomet’s own acetabular shells (manufactured to mate with the ceramic inserts) and femoral stems. A component comparison along with preclinical test results were used to demonstrate that the Biomet C²a-Taper™ Acetabular System performs similarly to the TRANSCEND System. Therefore, the clinical data referenced from the PMA for the TRANSCEND System has been used to predict the clinical outcome of the C²a-Taper™ Acetabular System.

## II. INDICATIONS FOR USE

The C²a-Taper™ Acetabular System is indicated for use in primary total hip arthroplasty in skeletally mature patients with non-inflammatory degenerative joint disease such as osteoarthritis, avascular necrosis, congenital hip dysplasia, and post-traumatic arthritis.

## III. CONTRAINDICATIONS

- Local and distant foci of infection
- Skeletally immature patients
- Osteoporosis
- Metabolic disorder, which may impair bone formation
- Osteomalacia
- Rapid joint destruction, marked bone loss or bone resorption apparent on roentgenogram
- Vascular insufficiency, muscular atrophy, or neuromuscular disease.

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# IV. WARNINGS and PRECAUTIONS

Please reference the C²a-Taper™ Acetabular System physician’s labeling to find the warnings and precautions.

# V. DEVICE DESCRIPTION

The C²a-Taper™ Acetabular System is a ceramic on ceramic hip articulating system. The bearing surfaces consist of ceramic femoral heads and acetabular liners. Both components are made of aluminum oxide manufactured by CeramTec AG.

The ceramic femoral heads and acetabular liners are intended to be used in conjunction with Biomet’s legally marketed (U.S.) titanium acetabular shells, acetabular screws, and titanium alloy femoral stem designs with a 12/14 taper.

## Acetabular Liners

The ceramic liners are available in 28mm and 32mm inside diameter (I.D.) sizes, which correspond to 37mm and 41mm outer diameter tapers, respectively. The 28mm liner is used with 48mm and 50mm shells. The 32mm liner is used with shells ranging in size from 52 to 70mm in 2mm increments.

## Acetabular Shells

The titanium alloy shells are designed with four fins and the outer surface is covered with a plasma sprayed porous coating of titanium alloy (Ti-6Al-4V) powder conforming to ASTM F 1580 (Standard Specification for Titanium and Titanium-6 Aluminum-4 Vanadium Alloy Powders for Coatings of Surgical Implants). The shells are available in two taper diameters: 37 and 41mm. The size 37mm taper is available in two outer diameters: 48 and 50mm. The size 41mm taper is available in 48 to 70mm diameters in 2 mm increments.

## Acetabular Screws

Titanium alloy screws in 6.5mm diameters are available for optional supplemental fixation. The 6.5mm dome screws are available in 15 to 70mm lengths.

## Femoral Heads

The 28mm and 32mm ceramic heads are available in three neck sizes: short, medium, and long. The short neck is equivalent to a -3.5mm or -4mm (depending on head diameter 28 and 32, respectively). The medium neck length is equivalent to standard heads (0mm), and the long neck is equivalent to a +3.5mm or a +4mm head (depending on head diameter 28 and 32, respectively).

## Femoral Stems

The titanium alloy 12/14 Taperloc® femoral stems in either a standard or lateralized design are partially porous coated with titanium alloy (Ti-6Al-4V) powder conforming to ASTM F 1580. The stems range in diameters from 5 to 25 mm and in lengths from 130 to 170 mm.

# VI. ALTERNATIVE PRACTICES AND PROCEDURES

Depending on individual circumstances, alternative procedures may include the use of other commercially available total hip replacement implants, non-surgical treatment such as reduced activity and/or pain medication, or other surgical treatments that do not

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involve the use of an implant such as hip joint fusion. Other bearing surface alternatives used in total hip replacement include: ceramic on polyethylene, metal on metal, and metal on polyethylene bearing articulations.

## VII. MARKING HISTORY

Biomet France, a subsidiary of Biomet Inc., has marketed a similar system (Eternity) in France since September 1999 using the same ceramic heads and liners. This is the only country in which Biomet Inc. has marketed these ceramic heads and liners. These devices have not been withdrawn from marketing for any reason related to safety or effectiveness.

## VIII. POTENTIAL ADVERSE EFFECTS OF THE DEVICE ON HEALTH

The C²a - Taper™ Acetabular System is similar to the previously approved TRANSCEND Ceramic Hip System (P010001). Biomet references the clinical data from P010001, under a licensing agreement, as clinical support for the C²a - Taper™ Acetabular System. The clinical data are relevant because the ceramic acetabular inserts and the ceramic femoral heads of the C²a - Taper™ Acetabular System are identical to the ceramic acetabular inserts and the ceramic femoral heads of the previously approved TRANSCEND System (same articulating surface). A system comparison between the C²a - Taper™ Acetabular System and the TRANSCEND System was performed to demonstrate that the systems perform similarly enough on the bench that the clinical data referenced can be used to predict the clinical outcomes for the C²a - Taper™ Acetabular System.

Please refer to Table 3 in Section X (Summary of Clinical Studies) for a tabulation of reported adverse events that occurred in the referenced study (P0100001).

### Potential Complications Associated with Any Total Hip Arthroplasty

1. Excessive wear of the ceramic components secondary to damage of mating wear surfaces or debris particles;
2. Although rare, metal sensitivity reactions in patients following joint replacement have been reported;
3. Implantation of foreign material in tissues can result in histological reactions involving macrophages and fibroblasts;
4. Possible detachment of the porous coating, which could lead to increased debris particles;
5. Pain;
6. Femoral or acetabular perforation, or bone fracture while seating the device;
7. Damage to blood vessels resulting in hematoma;
8. Temporary or permanent nerve damage resulting in pain or numbness of the affected limb;
9. Undesirable shortening or lengthening of the limb;
10. Traumatic arthrosis of the hip from intraoperative positioning of the extremity;
11. Cardiovascular disorders including venous thrombosis, pulmonary embolism, or myocardial infarction;
12. Temporary or permanent neuropathies;
13. Delayed wound healing;
14. Infection;

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15. Migration, loosening, subluxation, or dislocation of the prosthesis;
16. Periarticular calcification or ossification, with or without impediment to joint mobility;
17. Inadequate range of motion due to improper selection or positioning of components, by femoral impingement, and periarticular calcification; and
18. Death.

## Potential Complications Associated with C²a-Taper™ Acetabular System

1. Wear of the ceramic acetabular components has been reported following total hip replacement. Higher rates of wear may be initiated by particles of cement, metal, or other debris that can cause abrasion of the articulating surfaces. Higher rates of wear may shorten the useful life of the prosthesis, and lead to early revision surgery to replace the worn prosthetic components.
2. While rare, fatigue fracture of the prosthetic component can occur as a result of trauma, strenuous activity, improper alignment, or duration of service.
3. Component dissociation.
4. Breakage or chipping of the femoral head or acetabular insert.

## IX. SUMMARY OF PRECLINICAL STUDIES

The results of the preclinical testing listed below demonstrate that the C²a-Taper™ Acetabular System performs similarly on the bench to the CeramTec TRANSCEND Ceramic Hip System (P010001). The C²a-Taper™ Acetabular System uses the same ceramic balls and liners as the TRANSCEND System and uses Biomet’s own Taperloc stems and Acetabular cups to comprise the system. The comparability of the C²a-Taper™ Acetabular System and the TRANSCEND System was demonstrated through side-by-side component comparisons and a comparison of preclinical test results.

A battery of preclinical laboratory tests were conducted on the alumina ceramic material used to make the ceramic components. It conforms to the ASTM F603 (“Standard Specification for High-Purity Dense Aluminum Oxide for Medical Application”) and ISO 6474 (“Implants for Surgery – Ceramic materials based on high purity alumina”) requirements and has been shown to be safe and effective. The metal components that comprise the rest of this system are made from materials that have been used for many years in total hip replacement surgery.

The following preclinical studies were conducted on the C²a-Taper™ Acetabular System. All test results were determined to be sufficient for the intended use of these ceramic on ceramic articulating bearings.

## Wear Test

PMA P010001, incorporated by reference, includes results of a wear test designed to replicate an in vivo condition, comparing the amount of wear debris produced by the 28mm ceramic on ceramic couple to that of the traditional couple of polyethylene and cobalt chrome. This test is relevant to the C²a-Taper™ Acetabular System because the ceramic components of the reference submission and the C²a-Taper™ Acetabular System are identical.

The data from P010001 indicated that dimensional changes for the ceramic components after five million cycles were still below the resolution of the coordinate measuring

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system (2 μm). Weight loss and dimensional changes were too insignificant to be detected. There was a slight increase in surface roughness for both head and liner. The wear results conducted from this test showed that the ceramic on ceramic articulation surfaces used for the C²a- Taper™ Acetabular System produce no detectable wear after five million cycles.

## Ceramic Femoral Heads Testing

### A. Ultimate Compressive Strength

Size 28mm and 32mm femoral heads were tested. Testing used a 100° included angle steel cone for applying the load to the ball head, as described in ISO 7206-10 (Implants for surgery – Partial and total hip joint prostheses – Part 10: Determination of resistance to static load of modular femoral heads), which has superseded the ISO 7206-5 standard (Implants for surgery-Partial and total hip joint prostheses Part 5: Determination of resistance to static load of head and neck region of stemmed femoral components) referenced in the “FDA Draft Guidance Document for the Preparation of Premarket Notifications for Ceramic Ball Hip Systems” dated January 10, 1995 that is available at http://www.fda.gov/cdrh/ode/355.pdf. The load was applied slowly until the head fractured.

#### Pass/Fail Criteria

In accordance with the FDA guidance document, each femoral head passed with an average fracture strength greater than 46kN. In addition, no ball head fractured at a stress of less than 20kN and, therefore, all passed this test.

### B. Fatigue Strength

Femoral heads with the highest stress for each ball head diameter (i.e. longest neck) based on the ultimate compressive (static burst) strength results were tested. The components that break at the lowest load in the static burst test have the highest stress. A minimum of five (5) ball heads with the longest neck length from each ball head diameter were tested. This includes the 28L and the 32L.

Ti-6Al-4V test tapers were used for each test. The components were tested with a sinusoidal load of 1.4-14kN for 10 million cycles at a maximum rate of 25Hz or until fracture. All components survived after 10 million cycles and were tested for residual strength by applying an axial load until fracture. Testing parameters used were per the FDA draft guidance document cited above.

#### Pass/Fail Criteria

In accordance with the FDA Draft Guidance Document cited above, components showed no evidence of cracking or fracture after 10 million cycles and the post-fatigue static compression strengths exceeded 20 kN.

### C. Taper Pull-off Test

The longest neck lengths (28L & 32L) were tested because they have the least area of contact between the Ti-6Al-4V taper and the ceramic femoral ball head and represent the worst case testing. Five (5) ball heads were tested for both the 28L and the 32L.

Ti-6Al-4V test tapers were used for each test. The ceramic ball head was pre-loaded in compression onto the metal taper using 2 kN installation force. The pull-off required to separate the ceramic head from the metal taper was recorded.

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Pass/Fail Criteria

The pull-off strength exceeded 0.2 kN for a 2kN installation force. Currently no minimum strength requirement has been established for this test.

## Ceramic Liners Testing

### D. Torsion Strength

28mm and 32mm liners were tested. The smallest shell sizes (48/37mm for the 28mm liners and 52/41mm for the 32mm liners) were used for testing. This is the worst case condition for testing because these devices have the least taper surface contact area within this acetabular system.

The ceramic liner inserts were pressed into a metal back shell with an axial load of 2kN. A metal ball head was glued into the insert. A lever arm approximately 40mm in length was used to transform an axial force into a torque. The test used a nominal feed rate of 2mm/min. Load on the lever arm was monitored and transformed into torque on the insert. The torque required to cause the insert to slip was recorded.

### Pass/Fail Criteria

Torsional strengths exceeded a minimum value of 4 Nm, which is an upper bound estimate of the maximum torque that could conceivably occur in vivo. Currently no minimum strength requirement has been established for this test.

### E. Lever-out Strength

28mm and 32mm liners were tested. The smallest shell sizes (48/37mm for the 28mm liners and 52/41mm for the 32mm liners) were used for testing. This is the worst case condition for testing because these devices have the least taper surface contact area within this acetabular system.

First, a hole was bored in the liner at an angle of approximately 25° to the horizontal. Then, the liner was assembled into the shell with a 2kN axial load with a feed rate of 15 N/sec applied by a ceramic ball head. The liner/shell assembly was mounted in the lever-out fixture and a load was applied by a lever arm through the hole at a feed rate of 2mm/min. The load required to cause the liner to slip was recorded, subject to a maximum load of 1kN. Failures in the fixture or the shell were recorded.

### Pass/Fail Criteria

The lever-out strength values were greater than 30 Nm. Currently no minimum strength requirement has been established for this test.

### F. Push-out Strength

28mm and 32mm liners were tested. The smallest shell sizes (48/37mm for the 28mm liners and 52/41mm for the 32mm liners) were used for testing. This is the worst case condition for testing because these devices have the least taper surface contact area within this acetabular system.

The liners were pressed into a metal shell with a bore in the backside. The liners were pushed in by a ceramic head with an axial load of 2kN with a feed rate of 15 N/sec. The assembly was then placed on a metal ring that only touches the outside metal shell. Load was applied by a punch going through the bore on the backside. The load at which the insert came loose from the metal shell was recorded.

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## Pass/Fail Criteria

The push-out strength was greater than the 200N minimum requirement per the CeramTec qualification procedure.

## G. Ultimate Compressive Strength

28mm and 32mm liners were used for this testing. The smallest shell sizes (48/37mm for the 28mm liners and 52/41mm for the 32mm liners) were used for testing because these provide the highest stress conditions due to having the smallest cross sectional area.

Liners and metal shell inserts were assembled using a ceramic head with a 2kN load and a feed rate of 15 N/sec. The assembly was potted into the test fixture and load was supplied by a ceramic head until the liner fractured. The feed rate for the head was 2mm/min.

## Pass/Fail Criteria

The average fracture strength was greater than 46kN and no liner had a fracture stress of less than 25kN which are the CeramTec pass criteria.

## H. Fatigue Test

28mm liners were used for this testing. The smallest shell sizes (48/37mm for the 28mm liners) were used for testing because these provide the highest stress conditions due to having the smallest cross sectional area. This combination of the smallest insert liner and the smallest shell is considered the worst-case scenario. This assumption was verified by the Ultimate Compressive Strength test of the components.

Liners and metal shell inserts were assembled using a ceramic head with a 2kN load and a feed rate of 15 N/sec. Each assembly was then potted into a fixture using an aluminum-filled epoxy. Assemblies were placed in a tank containing Ringer’s solution. A 1.4-14kN sinusoidal load was applied to each liner at a maximum rate of 25Hz using a ceramic head. Tests were conducted to 10 million cycles. Tested samples were examined for signs of cracking and then subjected to compressive strength tests in order to determine the residual post-fatigue strength.

## Pass/Fail Criteria

Components showed no evidence of cracking or fracture after 10 million cycles at 1.4-14kN and residual compressive strengths were greater than 25kN.

## X. SUMMARY OF CLINICAL STUDIES

As previously stated, the C²a- Taper™ Acetabular System is similar to the previously approved TRANSCEND Ceramic Hip System (P010001). Biomet references the clinical data from P010001, under a licensing agreement, as clinical support for the safety and effectiveness of the C²a- Taper™ Acetabular System. The clinical data are relevant because the ceramic acetabular inserts of the C²a- Taper™ Acetabular System are identical to a subset of the ceramic acetabular inserts of the TRANSCEND system (P010001) and the ceramic femoral heads of the C²a- Taper™ Acetabular System are identical to the ceramic femoral heads of the previously approved system. C²a- Taper™ Acetabular System uses Biomet’s own acetabular shells (designed to mate with the

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ceramic inserts) and a subset of Biomet’s stems. The two systems were shown to perform similarly on the bench.

## Published Literature

Published literature of early results of the referenced ceramic hip system discuss significant improvement in average Harris Hip Scores and SF-12 scores. No fractures of the ceramic components were reported in these articles.¹,²

## Pivotal Clinical Study

The study was a prospective, multi-center, non-masked clinical trial of 959 procedures in 848 patients, comparing the referenced ceramic hip system to a historical control group.

Although the primary efficacy endpoint in the clinical study was the survivorship of the referenced ceramic hip system (as assessed at the two year postoperative interval), for the purpose of the clinical study, the primary efficacy endpoints included Harris Hip Score and radiographic assessments at 2 years, as well. In addition, patient satisfaction was assessed by the SF-12 at two years.

Complication rates were the primary safety endpoint.

## Study Design

The study was a prospective, multi-center, historical control, clinical trial. The historical control group was later selected as the population of patients implanted with a metal on polyethylene hip consisting of non-inflammatory degenerative joint disease cases. Study patients consisted of individuals over 21 years of age presenting for total hip arthroplasty due to osteoarthritis, congenital hip dysplasia, traumatic arthritis and avascular necrosis. A total of 329 procedures have been performed with the referenced ceramic hip system in the original clinical population (Original Clinical Population). An additional 630 devices were implanted under Continued Access. The total number (Original Clinical Population and Continued Access) meeting the inclusion/exclusion criteria as required by the protocol is 959 procedures in 848 patients. Over a two-year period, 211 hip prostheses (179 patients) with metal femoral stems and plastic cups were implanted in the control group.

## Pivotal Clinical Patient Assessment

Each patient was evaluated at the immediate and 6, 12, and 24-month post-operative intervals, unless otherwise indicated by complications. At each follow-up visit, a Harris Hip Score and SF-12 was administered as well as obtaining AP and lateral radiographs. Radiographs were reviewed by the implanting surgeon. There were no pre-specified success/failure criteria in the clinical study.

## Demographics

For the study population, there were a total of 965 procedures performed in 854 patients at 12 sites by 19 surgeons. Six of these patients did not meet study inclusion criteria (one procedure enrolled as a replacement for a previously implanted total hip replacement (THR) and five procedures performed in patients with rheumatoid arthritis). These six

¹ Garino, Jonathan P., M.D. “Modern Ceramic-on-Ceramic Total Hip Systems in the United States.” *Clinical Orthopedics and Related Research* 2000; 379:41-47.

² Murphy, Stephen B., M.D., and Wael K. Barsoum, M.D. “Ceramic-Ceramic Bearings in Total Hip Arthroplasty: Preliminary Clinical Results.” *The Orthopaedic Journal at Harvard Medical School* 2001;3:92-94.

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procedures are excluded from this analysis. Therefore, the primary analysis sample included 959 procedures for first hip replacements performed in 848 patients.

The patient accounting and Baseline Demographics are summarized in Tables 1 and 2. Note that there were 9 deaths, none of which were related to the study or to the device.

Table 1: Patient Accounting

| Evaluation Interval | Original Clinical Patient Population (n=329) | | | Continued Access Population (n=630) | | |
| --- | --- | --- | --- | --- | --- | --- |
| | TFU | EFU | AFU(%) | TFU | EFU | AFU(%) |
| Pre-Op | 329 | 329 | A100% (n=329) | 630 | 630 | 100% (n=630) |
| 6 months | 329 | 323 | 93% (n=300) | 602 | 602 | 71% (n=430) |
| 12 months | 329 | 321 | 91% (n=293) | 443 | 442 | 53% (n=233) |
| 24 months | 329 | 321 | 94% (n=302) | 151 | 150 | 0% (n=0) |

TFU = Theoretical Follow-Up; EFU = Expected Follow-Up (Theoretical Follow-Up minus deaths and removals without replacement); AFU = Actual Follow-up

Table 2: Baseline and Demographics

| Values | Total Study Procedures (n=959) | Historical Control Group (n=211) |
| --- | --- | --- |
| Mean Age in Years | 51.4 Years (range 20-80) | 62.7 years (range 22-87) |
| Gender | 595 (62%) Males
364 (38%) Females | 112 (53%) Males
99 (47%) Females |
| Mean Body Mass Index (kg/m²) | 28.8 (range 17.7-65.8) | 27.1 (range 22.8-40.9) |
| Diagnosis | | |
| Osteoarthritis | 692 (72.2%) | 180 (85.3%) |
| Avascular Necrosis | 189 (19.7%) | 31 (14.7%) |
| Traumatic Arthritis | 36 (3.8%) | 0 |
| Congenital Hip Dysplasia | 42 (4.4%) | 0 |
| Mean Baseline Total HHS (range 1-100) | 45.1 (range 8.3-95.9) | 42.7 (range 11-79) |
| Mean Baseline Pain HHS (range 0-44) | 12.9 (range 0-44) | 13.2 (range 0-30) |
| Mean Baseline Harris ROM° (range 0-5) | 3.8 (range -3.1-4.88) | 4.1 (range not available) |

## Safety and Effectiveness Data

### Safety Results

The adverse events related to total hip replacement surgery reported in the pivotal clinical study including 959 patients are listed in Table 3.

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| Table 3: Reported Adverse Events | | | | |
| --- | --- | --- | --- | --- |
| Event | Clinical Study (n=959) | | Historical Control Group (n=211) | |
| Systemic | Freq. | % of Pop. | Freq. | % of Pop. |
| Deaths | 9 | 0.9% | 0 | 0% |
| Pulmonary Embolism | 2 | 0.2% | 2 | 0.9% |
| Deep Vein Thrombosis | 4 | 0.4% | 0 | 0% |
| Local | Freq. | % of Pop. | Freq. | % of Pop. |
| Revisions/Removals^{1} | 11 | 1.1% | 8 | 3.8 |
| Breakage/Fracture of Component^{2} | 5 | 0.5% | 2 | 0.9% |
| Dislocation (single) of Component^{3} | 8 | 0.8% | 3 | 1.4% |
| Dislocation (recurrent) of Component^{4} | 2 | 0.2% | 0 | 0% |
| Femoral Fracture | 18 | 1.9% | 9 | 4.3% |
| Hematoma | 2 | 0.2% | 0 | 0% |
| Heterotopic Ossification | 1 | 0.1% | 1 | 0.5% |
| Infection: Deep, Early <1 year | 2 | 0.2% | 0 | 0% |
| Infection: Deep, Late > 1 year | 1 | 0.1% | 0 | 0% |
| Infection: Superficial | 7 | 0.7% | 0 | 0% |
| Loosening of Component | 3 | 0.3% | 2 | 0.9% |
| Migration of Component | 2 | 0.2% | 0 | 0% |
| Persistent Foot Drop | 2 | 0.2% | 0 | 0% |
| Pain | 10 | 1.0% | 0 | 0% |
| Perforation of Femur During Reaming | 2 | 0.2% | 0 | 0% |
| Wear of Component | 1 | 0.1% | 0 | 0% |
| Subsidence of Component | 3 | 0.3% | 2 | 0.9% |
| Soft Tissue Trauma | 0 | 0% | 0 | 0% |
| Wound Problems | 2 | 0.2% | 0 | 0% |
| Other Local Complication^{5} | 10 | 1.0% | 0 | 0% |
| Local-Hip | Freq. | % of Pop. | Freq. | % of Pop. |
| Trochanteric Bursitis | 16 | 1.7% | 1 | 0.5% |
| Trochanteric Non-union | 0 | 0% | 0 | 0% |
| Trochanteric Avulsion | 4 | 0.4% | 0 | 0% |

Notes:
1 See details in the following Table 9 for n=959
2 Clinical Study: Chipping of ceramic acetabular liner during placement requiring intraoperative revision.
Historical Control Group: Broken metal peg of acetabular cup.
3 2 were revised for this reason.
4 1 was revised for this reason.
5 Consisted of: 3 cases of irritation/inflammation; 2 cases where patients fell; 1 case of component mismatch; 1 case of liner malposition; 1 case where the acetabular shell seated too deeply in the reamed cavity; 1 case of hip flexor weakness; and 1 case where the anterior abductor pulled off.

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# Revisions and Removals

Eleven devices out of the 959 primary patients enrolled in the trial have been revised or removed. Table 4 summarizes the clinical information pertaining to these cases.

Table 4: Summary of Revisions and Removals

| Procedures | Age/Gender | Diagnosis | Duration of Implantation | Reason for Revision/Removal |
| --- | --- | --- | --- | --- |
| Revision of acetabular Component with bone graft and cage implantation | 50/F | AVN | 84 days | Migration of acetabular component |
| Revision of femoral head With a longer neck | 29/F | Congenital Hip Dysplasia | 1 day | Dislocation |
| Replaced acetabular component to larger size (32mm) and replaced femoral head to 35mm | 43/M | Severe osteoarthritis with mild hip dysplasia | 1 day | Dislocation |
| Replacement of acetabular component, liner, and femoral head. Repair of abductor mechanism. | 62/M | Osteoarthritis | 38 days | Persistent dislocation following closed reduction, trochanteric fracture with avulsion of abductors. |
| Revision followed by removal and Girdlestone procedure | 51/M | Traumatic arthritis | 210 days | Deep infection and stitch abscess |
| Replacement of acetabular liner | 36/F | Congenital hip dysplasia | 3 days | Acetabular liner disassociated from shell |
| Replacement of acetabular liner and femoral head | 41/M | Osteoarthritis | 14 days | Increasing pain, suspected infection |
| Replacement of acetabular liner and femoral head | 58/M | Avascular Necrosis | 953 days | Excessive wear due to impingement on acetabular cup rim |
| Replacement of femoral head from 32mm to 28mm | 50/M | Osteoarthritis | 1 day | Liner/head size mismatch noted on postoperative film |
| Replacement of (uncemented) femoral stem to cemented stem | 56/M | Osteoarthritis | 657 days | Pain and progressive subsidence due to undersized (uncemented) femoral stem |
| Replacement of femoral stem and head | 56/F | Osteoarthritis | 786 | Femoral component loosening |

## Efficacy results

Table 5, below, shows the mean and range of Harris Hip Scores for each study cohort preoperatively and two years postoperatively

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Table 5: Efficacy Results--HHS

| Primary Efficacy Assessment | Original Patient Population (n=329)^{1} | Continued Access Population (n=630)^{2} | Historical Control Group (n=211) |
| --- | --- | --- | --- |
| Preoperative mean HHS (range) | 44.8 (13-89) | 45.2 (8-96) | 42.7 (11-79) |
| 2 year postop mean HHS (range) | 94.8 (34-100) | 88.1 (17-100) | 92.7 (39-100) |
| % Excellent/Good Results (HHS 80-100 points) at 2 years postop | 92.2% | 76.9% | 88.2% |

Notes:
1 Original clinical study population includes the first 329 procedures enrolled in the pivotal clinical study. This includes replacements and removals prior to 24 months (n=9), death prior to 24 months (n=7), and cases in which only a partial Harris Hip Score at 24 months or later was available (n=4)
2 The Continued Access sample (N=630) includes procedures performed after the original population without Month 24+outcomes. Therefore, outcomes reported were defined on the basis of Last Observation carried Forward (LOCF) and represent the latest clinical results available for that procedure.

Any Radiographic Lucency
Radiolucencies were recorded at each follow-up visit based on if they involved the entire Gruen zone (7 AP femoral zones, 7 lateral femoral zones, 3 AP acetabular zones, and 3 lateral acetabular zones). Table 6 summarizes these results.

Table 6: Any Radiolucency

| Lucency | Original Study Population (n=329) | Historical Control Group (n=211) |
| --- | --- | --- |
| Femoral | 18 (5.5%) | 66 (31.3%) |
| Acetabular | 9 (2.8%) | 56 (26.5%) |
| Overall | 22 (6.8%) | 77 (36.5%) |

In addition, any subsidence was reported for the original study population for 0.9% of the femoral stems and 0.3% of the acetabular cups. In the historical control group there were two instances of femoral stem subsidence (1.0%).

Implant Survivorship
Implant survivorship was the pre-specified primary endpoint in the pivotal clinical study of the referenced ceramic hip system. Kaplan-Meier cumulative survivorship is shown in Tables 7 and 8 for the referenced ceramic hip system and the historical control group over time.

The cumulative Kaplan-Meier survivorship values for the femoral or acetabular component are shown in Tables 7 and 8 based on the longest duration of follow-up available in each study cohort.

Table 7: Referenced Ceramic Hip System Implant Survivorship

| Interval | Number Entering Interval | Number Withdrawn | Number Revised in Interval | Cumulative Survival | Standard Error |
| --- | --- | --- | --- | --- | --- |
| 12 months | 528 | 69 | 8 | 0.9909 | 0.0041 |
| 24 months | 279 | 78 | 1 | 0.9876 | 0.0066 |
| 36 months | 1 | 0 | 0 | 0.9876 | 0.0562 |

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Table 8: Historical Control Group Implant Survivorship

| Interval | Number Entering Interval | Number Withdrawn | Number Revised in Interval | Cumulative Survival | Standard Error |
| --- | --- | --- | --- | --- | --- |
| 12 months | 234 | 8 | 3 | 0.9870 | 0.0074 |
| 34 months | 223 | 70 | 1 | 0.9817 | 0.0090 |
| 36 months | 152 | 103 | 1 | 0.9719 | 0.0131 |
| 48 months | 48 | 34 | 3 | 0.8779 | 0.0481 |
| 60 months | 11 | 11 | 0 | 0.8779 | 0.0481 |

Patient Success Criteria

Table 9 describes the proportion of patients meeting individual clinical success criteria at 2 years postoperatively.

Table 9: Patient Success Criteria at 2 Years

| Patient Success Criteria | Original Patient Population (n=329)^{1} | Whiteside Clinical Study (n=211) |
| --- | --- | --- |
| Absence of Revision (5) | 96.7% (n=318) | 98.1% (n=207) |
| Total HHS > 70 | 96.8% (n=318) | 95.3% (n=201) |
| No Complete Radiolucencies^{2} | 99.7% (n=328) | 88.5% (n=184) |

Notes:

1. The Original Patient Population sample includes procedures in the Complete Endpoint (N=309) sample plus procedures with revisions, replacements, or removals prior to Month 24 (N=9); who died prior to Month 24 (N=7); or who had only a partial Harris Hip Score assessment at Month 24 or later (N=4). This sample was constructed in order to facilitate an analysis of efficacy and safety endpoints for hips that were at-risk for a complication and that ‘completed the study.’ For Complete Follow-up procedures (N=329), the Month 24+ endpoint was defined as the Month 24 value and if not available, value after Month 24 were used. Original pivotal clinical population includes the first 329 procedures enrolled in the clinical study. This includes replacements and removals prior to 24 months (n=9), deaths prior to 24 months (n=7) and cases in which only a partial Harris Hip score at 34 months or later was available (n=4).

2. Absence of complete radiolucency was determined by radiographic evaluation for four views: acetabular AP view (3 regions), acetabular lateral view (3 regions) femoral stem AP view (7 regions), and femoral stem lateral view (7 regions). Complete radiolucency in a view was defined to be present if there was any radiolucency present in all zones comprising that view. Absence of complete radiolucency was defined to be present if none of these four views had complete radiolucency.

XI. CONCLUSIONS DRAWN FROM THE STUDIES

The preclinical and referenced clinical data provide reasonable assurance that the C²a-Taper™ Acetabular System is safe and effective for total hip replacement in patients with osteo/degenerative arthritis, avascular necrosis, and related diagnoses.

A system comparison analysis between the C²a-Taper™ Acetabular System and the TRANSCEND Ceramic Hip System (P010001) was performed to demonstrate that the systems perform similarly enough on the bench that the clinical data referenced above can be used to predict the clinical outcomes for the C²a-Taper™ Acetabular System.

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# XII. PANEL RECOMMENDATIONS

In accordance with the provisions of section 515(c)(2) of the act as amended by the Safe Medical Devices Act of 1990, this PMA application was not referred to the Orthopedic Devices Panel, an FDA advisory committee, for review and recommendation because the information in the PMA substantially duplicates information previously reviewed by this panel.

# XIII. CDRH DECISION

The applicant has adequately submitted all answers to the FDA’s questions and comments for their PMA application. The preclinical data and similarities in device design to the previously approved ceramic hip system (P010001) provide reasonable assurance that the C²a-Taper™ Acetabular System is safe and effective when used as directed for total hip arthroplasty patients requiring total hip arthroplasty due to non-inflammatory degenerative joint disease (NIDJD) such as osteoarthritis, avascular necrosis, congenital hip dysplasia, and post-traumatic arthritis.

In addition, the applicant has agreed to conduct a 10-year post-approval study to evaluate the long term safety and effectiveness of the C²a-Taper™ Acetabular System. The study will enroll a minimum of 257 subjects, of whom a minimum of 160 subjects will be followed to 5 years and a minimum of 100 subjects will be followed out to 10 years. During the first 5 years, clinical, radiographic, and subject self-assessment information will be collected for each subject. For the sixth through tenth postoperative years, subjects will be asked to return an outcomes questionnaire designed to determine the status of their hip replacement.

The applicant’s manufacturing facilities were inspected and determined to be in compliance with the Quality System Regulation (21 CFR Part 820).

FDA issued an approval order on December 16, 2005.

# XIV. APPROVAL SPECIFICATIONS

Directions for Use: See the Device Labeling

Hazards to Health from Use of the Device: See Indications, Contraindications, Warnings, Precautions and Adverse Events in the label

Post-Approval Requirements and Restrictions: See Approval Order