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| General |
| Study Status |
Completed |
Application Number /
Requirement Number |
P040033 / PAS002 |
| Date Original Protocol Accepted |
05/09/2006
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| Date Current Protocol Accepted |
05/09/2006
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| Study Name |
UK Study
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| Device Name |
BIRMINGHAM HIP RESURFACING (BHR) SYSTEM
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| General Study Protocol Parameters |
| Study Design |
Prospective Cohort Study
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| Data Source |
New Data Collection
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| Comparison Group |
No Control
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| Analysis Type |
Analytical
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| Study Population |
Transit. Adolescent B (as adults) : 18-21 yrs,
Adult: >21
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| Detailed Study Protocol Parameters |
| Study Objectives |
The study design is a single arm, cohort study.
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| Study Population |
Study population is as per device indication. Patients who underwent Birmingham Hip Resurfacing (BHR) System, a metal on metal resurfacing artificial hip replacement system, surgically implanted to replace a hip joint. The BHR System is intended for patients who, due to their relatively youneger age or increased activity level may not be suitable for traditional total hip arthroplasty, due to an increased possibility of requiring future ipsilatcral hip joint revision.
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| Sample Size |
The sample size is 350 patients.
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| Key Study Endpoints |
Study endpoints include OSHIP scores and device survival.
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| Follow-up Visits and Length of Follow-up |
At the time of PMA submission, all subjects had passed their 5 year post-implantation anniversary. Subjects will be followed annually through the use of self-assessment questionnaires until they reach 10 years of follow-up. At the ten year interval, a final clinical and radiographic examination will occur in addition to the questionnaire.
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| Interim or Final Data Summary |
| Interim Results |
A total of 22 deaths (27 hips) have occurred within the original 350 subject (400 hips) study population prior to completion of both 10 year study activities. No new deaths are reported in this report. Radiographic evaluations are done at the 10 year clinical evaluation. Radiographic information for patients seen at the 10 year interval is presented below. Of the 400 hips eligible for radiographic evaluation, 295 have data available.
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| Actual Number of Patients Enrolled |
A total of 350 patients and 400 hips were enrolled in the study.
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| Actual Number of Sites Enrolled |
Two study sites in the United Kingdom participated in the study.
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| Patient Follow-up Rate |
The follow-up rate for clinical examination was 89.5% at 10 post-operative years.
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| Final Safety Findings |
Heterotopic ossification of all grades was seen in 12.0% at 10 years; however, grade III and IV
heterotopic ossification was found in only 1.3% hips..
According to the independent radiographic review of the acetabular cup area, 13/316 hips (4.1%) showed some degree of radiolucency at 10 year follow-up. No hips were defined as radiographic failures for the acetabular component, which would have been denoted by a score ranging from
7, 8, or 9.
According to independent radiographic review, femoral radiolucencies were seen in 12/316 (3.8%) hips. Radiographic failure, represented by a score of 7-9 was found in 1/316 (0.32%) hips evaluated.
A total of 19/400 revisions (4.8%) of the BHR System are included in the final disposition of the population at 10 years.
Infection was a prominent contributor to revision accounting for 6/19 (31.6%) of revisions between the 2nd and 5th postoperative years. Collapsed femoral head was also a condition, which led to 4/19 (21.1%) of the revisions, and was especially prevalent around year 5 and after. Although not as prevalent, femoral neck fracture led to 3/19 (15.8%) revisions
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| Final Effect Findings |
At the 10 year follow up, 281/319 (88.1%) had OSHIP (Oswestry-modified Harris Hip Scores) of 80 or above. Specifically, 228/319 (71.5%) were at least 90 or above and another 53/319 (16.6%) were above 80 at 10 years.
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| Study Strengths & Weaknesses |
An important study strength is the 89.5% follow-up rate over 10 years.
A weakness of the study was the fact that all patients were implanted by the design surgeon, limiting generalization of the results.
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| Recommendations for Labeling Changes |
Yes. Ten-year device performance data can be updated
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