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

This retrospective study will review the Anderson Orthopaedic Institute's initial experience among a consecutive series of 126 patients who had primary total hip arthroplasty using a metal-on-metal articulation consisting of a DePuy Pinnacle cup with an Ultamet liner coupled with a 36-mm cobalt-chrome alloy femoral head. The relationship between metal ion levels, cup orientation, osteolysis, radiographic implant stability and clinical outcome measures including component revision, complications, patient satisfaction and Harris Hip Scores will be evaluated.

Study Overview

• Status: Completed
• Conditions: Osteoarthritis
• Intervention / Treatment: Device: Metal-on-metal primary total hip arthroplasty (DePuy )

Detailed Description

Metal-on-metal bearings for total hip arthroplasty are an alternative to traditional polyethylene bearing surfaces and hip simulators studies have shown that metal-on-metal bearings have lower wear than metal-on-polyethylene bearings. In addition, simulator studies indicate that the amount of wear decreases as head size increases allowing the use of larger head diameters than possible with other bearing surfaces. Since dislocation is currently the most common reason for reoperation in the United States, representing 22.5% of hip revisions, the combination of low wear and larger head sizes to reduce dislocation hold the promise of improving outcome among total hip arthroplasty patients. While there are potential advantages to metal-on-metal bearings, a few concerns have been noted in the literature. Although the total volume of wear is low with these bearings, the articulation generates metal debris that may be related to patient and surgical factors such as implant positioning. Despite a reduced wear volume, there is also the possibility that an increased bioreactivity associated with metal debris might induce an osteolytic response or local tissue hypersensitivity reaction.

This study will retrospectively review the outcome of a consecutive series of 126 patients who had 131 primary THAs performed between April 2001 and November 2002 at the Anderson Clinic with a Pinnacle acetabular cup, an Ultamet insert and a 36-mm cobalt-chrome alloy femoral head. These total hip arthroplasties represent the Anderson Orthopaedic Institute's in initial experience with this implant. The relationship between metal ion levels, cup orientation, osteolysis, radiographic implant stability and clinical outcome measures including component revision, complications, patient satisfaction and Harris Hip Scores will be evaluated. The outcome data from our analysis will also be compared with the data from other published series with metal-on-metal bearing surfaces. Serial radiographs obtained as part of routine post-operative care will be used to evaluate osteolysis, implant stability and radiographic complications such as periprosthetic fracture. The area of each osteolytic region will be measured on the AP pelvic x-ray using Martell's Hip Analysis Suite. Computed tomography (CT) scans obtained as part of routine follow-up will be also analyzed to identify regions of acetabular osteolysis. The volume and location of each osteolytic defect identified on CT will be evaluated using three-dimensional image analysis software (Analyze, Biomedical Imaging Resource, Rochester, MN). A three-dimensional (3D) reconstruction of the pelvis, cup and acetabular osteolytic lesions will also be generated from the CT image data. This reconstruction will be oriented to simulate the AP pelvic radiographic view. Cobalt and chromium ion level data will be compiled for patients who had blood drawn to evaluate metal ion levels. The mean and median blood metal-ion levels for these patients will be calculated and the results will be compared to the metal-ion levels reported in the literature.

• Study Type: Observational
• Enrollment (Actual): 126

Contacts and Locations

Study Locations

• United States
  • Virginia
    • Alexandria, Virginia, United States, 22306
      • Anderson Orthopaedic Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

A consecutive series of patients who had primary total hip arthroplasties performed at the Anderson Clinic using DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.

Description

Inclusion Criteria:

• Primary total hip arthroplasty patients who had surgery between April 2001 and November 2002 who were implanted with a Pinnacle acetabular cup, an Ultamet metal-on-metal insert and a 36mm cobalt-chrome alloy femoral head

Exclusion Criteria:

• Revision total hip arthroplasties
• Primary total hip arthroplasties using Ultamet liners coupled with 28-mm femoral heads

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Metal-on-Metal Total Hip Arthroplasties; Consecutive series of patients who had metal-on-metal primary total hip arthroplasty performed with DePuy Pinnacle cups, Ultamet metal liners and 36-mm cobalt-chromium alloy femoral heads.	Device: Metal-on-metal primary total hip arthroplasty (DePuy ); Replacement of a patient's native hip with an artificial implant featuring a metal-on-metal articulation; Other Names: DePuy Pinnacle acetabular cup; DePuy Ultamet metal liner; DePuy 36-mm femoral head

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Metal Ion Levels Per Participant	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.	At a mean of 4.2 years after primary total hip arthroplasty

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cup Orientation Per Hip	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.	On the first post-operative anteroposterior pelvic radiograph after primary total hip arthroplasty
Harris Hip Score Per Hip	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.	At a mean of 5.6 years after primary total hip arthroplasty
Osteolysis Per Hip	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.	At a mean of 5.6 years after primary total hip arthroplasty
Implant Stability Per Hip	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.	At a mean of 5.6 years after primary total hip arthroplasty
Component Revision Per Hip	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.	At a mean of 6.7 years after primary total hip arthroplasty
Patient Satisfaction Per Hip	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.	At a mean of 5.6 years after primary total hip arthroplasty

Collaborators and Investigators

• Sponsor: Anderson Orthopaedic Research Institute
• Collaborators: DePuy Orthopaedics
• Investigators: Principal Investigator: Robert H Hopper, Jr., PhD, Anderson Orthopaedic Research Institute

Publications and helpful links

General Publications

• MacDonald SJ. Metal-on-metal total hip arthroplasty: the concerns. Clin Orthop Relat Res. 2004 Dec;(429):86-93. doi: 10.1097/01.blo.0000150309.48474.8b.
• Bozic KJ, Kurtz S, Lau E, Ong K, Chiu V, Vail TP, Rubash HE, Berry DJ. The epidemiology of bearing surface usage in total hip arthroplasty in the United States. J Bone Joint Surg Am. 2009 Jul;91(7):1614-20. doi: 10.2106/JBJS.H.01220.
• Bozic KJ, Kurtz SM, Lau E, Ong K, Chiu V, Vail TP, Rubash HE, Berry DJ. The epidemiology of revision total knee arthroplasty in the United States. Clin Orthop Relat Res. 2010 Jan;468(1):45-51. doi: 10.1007/s11999-009-0945-0. Epub 2009 Jun 25.
• Dowson D, Hardaker C, Flett M, Isaac GH. A hip joint simulator study of the performance of metal-on-metal joints: Part II: design. J Arthroplasty. 2004 Dec;19(8 Suppl 3):124-30. doi: 10.1016/j.arth.2004.09.016.
• Rieker CB, Schon R, Kottig P. Development and validation of a second-generation metal-on-metal bearing: laboratory studies and analysis of retrievals. J Arthroplasty. 2004 Dec;19(8 Suppl 3):5-11. doi: 10.1016/j.arth.2004.09.017.
• Silva M, Heisel C, Schmalzried TP. Metal-on-metal total hip replacement. Clin Orthop Relat Res. 2005 Jan;(430):53-61. doi: 10.1097/01.blo.0000149995.84350.d7.
• Beaule PE, Campbell P, Mirra J, Hooper JC, Schmalzried TP. Osteolysis in a cementless, second generation metal-on-metal hip replacement. Clin Orthop Relat Res. 2001 May;(386):159-65. doi: 10.1097/00003086-200105000-00020.
• Willert HG, Buchhorn GH, Fayyazi A, Flury R, Windler M, Koster G, Lohmann CH. Metal-on-metal bearings and hypersensitivity in patients with artificial hip joints. A clinical and histomorphological study. J Bone Joint Surg Am. 2005 Jan;87(1):28-36. doi: 10.2106/JBJS.A.02039pp.
• Engh CA Jr, Ho H, Engh CA. Metal-on-metal hip arthroplasty: does early clinical outcome justify the chance of an adverse local tissue reaction? Clin Orthop Relat Res. 2010 Feb;468(2):406-12. doi: 10.1007/s11999-009-1063-8. Epub 2009 Sep 1.

Helpful Links

• Website for Anderson Orthopaedic Research Institute

Study record dates

Study Major Dates

• Study Start: December 1, 2011
• Primary Completion (Actual): June 1, 2012
• Study Completion (Actual): June 1, 2012

Study Registration Dates

• First Submitted: November 23, 2011
• First Submitted That Met QC Criteria: November 29, 2011
• First Posted (Estimate): November 30, 2011

Study Record Updates

• Last Update Posted (Estimate): October 9, 2013
• Last Update Submitted That Met QC Criteria: August 1, 2013
• Last Verified: August 1, 2013

More Information

Terms related to this study

• Keywords: Outcome; Hip replacement; Osteolysis; Metal-on-metal bearings; Metal ion levels
• Additional Relevant MeSH Terms: Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Arthritis; Osteoarthritis
• Other Study ID Numbers: AORI2011-0100; Study #09013 (Other Grant/Funding Number: DePuy Orthopaedics, Inc.)