Trial Outcomes & Findings for A Five-Year Metal-on-Metal Retrospective Clinical Study (NCT NCT01481896)

NCT ID: NCT01481896

Last Updated: 2013-10-09

Results Overview

Metal ion levels include cobalt and chromium ion levels determined from tests of blood samples. Metal ion levels are reported per participant since blood samples were taken from individual participants who could have had one or both hips replaced.

• Recruitment status: COMPLETED
• Target enrollment: 126 participants
• Primary outcome timeframe: At a mean of 4.2 years after primary total hip arthroplasty
• Results posted on: 2013-10-09

Participant Flow

For this retrospective study, the Anderson Orthopaedic Research Institute's database was used to identify a consecutive series of the first 126 patients who had 131 primary total hip arthroplasties using a Pinnacle acetabular cup, an Ultamet metal-on-metal insert and a 36-mm cobalt-chrome alloy femoral head.

No patient from the consecutive series of hip replacements performed between April 2001 and November 2002 was excluded.

Participant milestones

Measure	Metal-on-Metal Total Hip Arthroplasties Consecutive series of primary total hip arthroplasties performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.
Overall Study STARTED	126
Overall Study Min 4.75 yr Follow-up, Revised or Dead	114
Overall Study COMPLETED	114
Overall Study NOT COMPLETED	12

Reasons for withdrawal

Measure	Metal-on-Metal Total Hip Arthroplasties Consecutive series of primary total hip arthroplasties performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.
Overall Study Lost to Follow-up	12

Baseline Characteristics

A Five-Year Metal-on-Metal Retrospective Clinical Study

Baseline characteristics by cohort

Measure	Metal-on-Metal Total Hip Arthroplasties n=131 Participants Consecutive series of primary total hip arthroplasties performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.
Age, Categorical <=18 years	0 Participants n=93 Participants
Age, Categorical Between 18 and 65 years	121 Participants n=93 Participants
Age, Categorical >=65 years	10 Participants n=93 Participants
Age Continuous	53 years STANDARD_DEVIATION 10 • n=93 Participants
Sex: Female, Male Female	57 Participants n=93 Participants
Sex: Female, Male Male	74 Participants n=93 Participants
Region of Enrollment United States	131 participants n=93 Participants

PRIMARY outcome

Timeframe: At a mean of 4.2 years after primary total hip arthroplasty

Population: Patients who had blood drawn and analyzed for serum cobalt levels as part of routine care are included.

Metal ion levels include cobalt and chromium ion levels determined from tests of blood samples. Metal ion levels are reported per participant since blood samples were taken from individual participants who could have had one or both hips replaced.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=65 Participants Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels n=62 Participants Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Metal Ion Levels Per Participant	1.4 micrograms per liter Interval 0.0 to 37.0	2.1 micrograms per liter Interval 0.0 to 28.9

SECONDARY outcome

Timeframe: On the first post-operative anteroposterior pelvic radiograph after primary total hip arthroplasty

Population: Cup orientation was measured for all 131 total hip replacements included in the study population.

Cup orientation including abduction and anteversion is determined using follow-up radiographs. Since a participant with both hips replaced could have different cup orientations for each hip, cup abduction and anteversion angles are reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=131 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels n=126 Participants Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Cup Orientation Per Hip	39 degrees Interval 23.0 to 59.0	19 degrees Interval 7.0 to 35.0

SECONDARY outcome

Timeframe: At a mean of 5.6 years after primary total hip arthroplasty

Harris Hip Scores are derived from a patient questionnaire and physical examination. Since a participant with both hips replaced could have different Harris Hip Scores for each hip, the Harris Hip Scores are reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=114 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Harris Hip Score Per Hip	95 units on a scale Interval 49.0 to 100.0	—

SECONDARY outcome

Timeframe: At a mean of 5.6 years after primary total hip arthroplasty

Population: Patients who had radiographs or computed tomography (CT) scans taken as part of routine care were included.

Osteolysis is defined as localized areas of peri-prosthetic bone loss that did not exist prior to surgery and is evaluated using radiographs and CT scans. Since a participant with both hips replaced could have a osteolysis present or absent for each hip, osteolysis is reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=108 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels n=38 hips Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Osteolysis Per Hip	3 Number of hips with osteolysis	2 Number of hips with osteolysis

SECONDARY outcome

Timeframe: At a mean of 5.6 years after primary total hip arthroplasty

Population: All hips that had a follow-up x-ray taken at least 4.75 years after their joint replacement were included.

Implant stability is classified and stable/bone ingrown, fibrous fixed or loose and evaluated using conventional radiographs. Since a participant with both hips replaced could have a different type of stability for each hip, implant stability is reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=108 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels n=108 hips Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Implant Stability Per Hip Bone ingrown	105 number of hips	108 number of hips
Implant Stability Per Hip Fibrous stable	2 number of hips	0 number of hips
Implant Stability Per Hip Loose	1 number of hips	0 number of hips

SECONDARY outcome

Timeframe: At a mean of 6.7 years after primary total hip arthroplasty

For implants that require a component revision, the reason for the revision is determined based on the pre-operative history and operative findings at the time of revision. Since a participant with both hips replaced could have a revision of each hip, component revision is reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=131 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Component Revision Per Hip Stem revision for aseptic loosening	1 number of hips	—
Component Revision Per Hip Broken stem	2 number of hips	—
Component Revision Per Hip Liner & head exchange for groin pain & osteolysis	1 number of hips	—

SECONDARY outcome

Timeframe: At a mean of 5.6 years after primary total hip arthroplasty

Whether or not an individual is satisfied with the outcome of their hip arthroplasty is evaluated using a questionnaire. Since a participant with both hips replaced could have a different level of satisfaction for each hip, patient satisfaction is reported per hip.

Outcome measures

Measure	Patients With Serum Cobalt Levels n=106 hips Patients were recommended to have blood drawn for evaluation of serum cobalt levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. Among all the labs that performed metal level assessments, the cobalt detection limit varied from 0.5 to 1.0 microgram per liter. Patients with undetectable cobalt levels were assigned a value of zero. A patient's cobalt level was considered high if it was 7 micrograms per liter or greater.	Patients With Serum Chromium Levels Patients were recommended to have blood drawn for evaluation of serum chromium levels if they were considered to be active or thought to be at risk for an adverse local tissue reaction. Blood was drawn at our hospital or a facility of the patient's choice. The chromium detection limit was 0.1 micrograms per liter for all labs that performed metal level assessments. Patients with undetectable chromium levels were assigned a value of zero. A patient's chromium level was considered high if it was 7 micrograms per liter or greater.
Patient Satisfaction Per Hip Satisfied	106 number of participants	—
Patient Satisfaction Per Hip Unsatisfied	0 number of participants	—

Adverse Events

Metal-on-Metal Total Hip Arthroplasties

Serious events: 12 serious events

Other events: 16 other events

Deaths: 0 deaths

Serious adverse events

Measure	Metal-on-Metal Total Hip Arthroplasties n=131 participants at risk Consecutive series of primary total hip arthroplasties performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.
Surgical and medical procedures Component Revision	3.1% 4/131 • Number of events 4 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
General disorders Death	3.2% 4/126 • Number of events 4 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Surgical and medical procedures Irrigation & Debridement for Hematoma	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Surgical and medical procedures Irrigation & Debridement for Infection	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Surgical and medical procedures Dislocation	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Vascular disorders Post-operative Fat Embolism	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.

Other adverse events

Measure	Metal-on-Metal Total Hip Arthroplasties n=131 participants at risk Consecutive series of primary total hip arthroplasties performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.
Blood and lymphatic system disorders Serum Metal Levels of 7 micrograms/L or higher	9.2% 6/65 • Number of events 6 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Femoral osteolysis on x-ray	2.8% 3/108 • Number of events 3 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Pelvic osteolysis on computed tomography scan	5.3% 2/38 • Number of events 2 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Loose stem on x-ray	0.93% 1/108 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Hip Subluxation	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Greater Trochanter Fracture	1.5% 2/131 • Number of events 2 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Groin Pain	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Thigh pain	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Pubic ramus fracture	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Abnornal sensation with range of motion	0.76% 1/131 • Number of events 1 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.
Musculoskeletal and connective tissue disorders Fibrous stable stem	1.9% 2/108 • Number of events 2 • Adverse events were evaluated from the time of surgery to a mean follow-up of 6.7±2.4 years, ranging from 0 to 10.8 years, and were compiled by querying the Anderson Orthopaedic Research Institute's database for post-operative complications and revisions. All 131 hips were considered at risk for each of the adverse events with the following exceptions: death uses the 126 study participants; elevated ion levels uses the 65 patients with ion measurements; femoral osteolysis, stem loosening and fibrous stem stability use the 108 hips with x-rays; and pelvic osteolysis uses the 38 hips with CT scans.

Additional Information

Robert H. Hopper, Jr., PhD

Anderson Orthopaedic Research Institute

Phone: (703) 619-4411

Email: research@aori.org

Results disclosure agreements

• Principal investigator is a sponsor employee Any paper drafted regarding the results of the study shall be sent to Depuy Clinical Research for review and comment at least thirty (30) days before being submitted for publication; the same shall apply to abstracts, except the time for review by DePuy shall be ten (10) days. DePuy will promptly inform the authors of any changes deemed necessary to preserve the confidentiality of proprietary information or to ensure scientific accuracy.
• Publication restrictions are in place

Restriction type: OTHER