In January 2005, the oversight responsibility of the Post-Approval Studies Program was transferred to the Division of Epidemiology (DEPI) of the Office of Surveillance and Biometrics (OSB)/Center for Devices and Radiological Health (CDRH).
The CDRH Post-Approval Studies Program encompasses design, tracking, oversight, and review responsibilities for studies mandated as a condition of approval of a premarket approval (PMA) application, protocol development product (PDP) application, or humanitarian device exemption (HDE) application. The program helps ensure that well-designed post-approval studies (PAS) are conducted effectively and efficiently and in the least burdensome manner.
CDRH has established an automated, internal tracking system that efficiently identifies the reporting status of active PAS studies ordered since January 1, 2005 based on study timelines incorporated in study protocols and agreed upon by the CDRH and applicants. This system represents CDRH's effort to ensure that all PAS commitments are fulfilled in a timely manner.
In addition, CDRH launched this publicly available webpage to keep all stakeholders informed of the progress of each PAS. The webpage displays general information regarding each PAS, as well as the overall study status (based on protocol-driven timelines and the adequacy of the data) and the applicant's reporting status for each submission due.
Transit. Adolescent B (as adults) : 18-21 yrs,
Detailed Study Protocol Parameters
Study Design Description
The study design is a single arm, cohort study.
Study Population Description
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.
The sample size is 350 patients.
Study endpoints include OSHIP scores and device survival.
Followup Visits and Length of Followup
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.
Final Study Results
Actual Number of Patients Enrolled
A total of 350 patients and 400 hips were enrolled in the study.
Actual Number of Sites Enrolled
Two study sites in the United Kingdom participated in the study.
Patient Followup Rate
The follow-up rate for clinical examination was 89.5% at 10 post-operative years.
Final Safety Findings
Heterotopic ossification of all grades was seen in 12.0% at 10 years; however, grade III
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
Final Effectiveness 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.
Study Strengths and 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.
Recommendations for Labeling Changes
Yes. Ten-year device performance data can be updated