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Published on: April 11, 2012
Extendible endoprostheses for the skeletally immature
1Division of Biomedical Engineering, University College, London, England.
Clinical Orthopaedics and Related Research
|January 1, 1996
Summary
Aseptic loosening is the primary reason for failure in Stanmore custom extendible endoprosthetic replacements in children. This highlights a high complication rate requiring revision surgery, particularly for distal femoral replacements.
Area of Science:
- Orthopedic surgery
- Biomedical engineering
- Pediatric oncology
Background:
- Custom-made extendible endoprostheses are used in skeletally immature patients, often for bone tumor treatment or revision of failed implants.
- Stanmore extendible endoprostheses have utilized four distinct extension mechanisms since 1976.
Purpose of the Study:
- To evaluate implant survival and identify failure modes in Stanmore custom-made extendible endoprosthetic replacements in pediatric patients.
- To analyze the predominant causes of revision surgery in this patient cohort.
Main Methods:
- Retrospective analysis of 168 consecutive Stanmore custom-made extendible endoprosthetic replacements in skeletally immature patients.
- Survival analysis was performed to determine implant longevity and failure probabilities.
- Failure modes, including aseptic loosening, mechanism jamming, infection, and premature extension, were documented.
Main Results:
- Aseptic loosening was the most frequent cause of implant-related failure, accounting for 19 of 38 revisions.
- The overall 5-year survival probability against implant-related failure was 0.512.
- Distal femoral replacements showed a higher incidence of aseptic loosening, with a 5-year survival probability of 0.773 against this specific failure mode.
Conclusions:
- Aseptic loosening is the predominant failure mode for Stanmore custom-made extendible endoprostheses in skeletally immature patients.
- The high rate of revision surgery underscores the significant complication profile associated with these extendible implants.
- Further research into improving the longevity and reducing failure rates, especially aseptic loosening in distal femoral reconstructions, is warranted.
