Title: MRI study of bioabsorbable poly-L-lactic acid devices used for fixation of fractures and osteotomies
Authors: Marumo K, Sato Y, Kurosaka D
Source: Journal of Orthopaedic Science 2006; 11:154-158
PODIATRIC RELEVANCE:
Bioabsorbable poly-L-lactic acid devices (PLLA-Ds) may be used by the podiatric surgeon for internal fixation. Consideration should be given to the possibility of mechanical insufficiency when the cross-sectional area of a PLLA-D extends beyond the cross-sectional area of the osteosynthesis site.
METHODS:
Thirteen patients with osteoarthritis of hip joints were operated on using 4.5mm PLLA-D pins for fixation. Nine patients with displaced malleolar ankle fractures were operated on using 4.0mm cancellous, 3.5 and 4.0mm cortical PLLA screws for fracture fixation. The period from operation to the time of the study ranged from 17 to 78 months. The postoperative radiographic findings were evaluated for union, and changes around the implant holes were classified as sclerosis, resorption, or no change. MRI was carried out to estimate changes in the PLLA-Ds.
RESULTS:
Bone union was obtained in all cases; clinical complications such as infection, joint effusion, soft tissue irritation due to PLLA-D deviation, and motion pain in the joints were not observed. The MRI study suggested that water content in PLLA-D increased mainly due to biodegradation and that implants were not replaced by bony tissue.
COMMENTS:
No clinical complications were evident in this small study of 22 patients. The PLLA-Ds were not replaced by bony tissue in any of the patients. Mechanical insufficiency with fracture could create a detrimental complication with the possible need for bone grafting to fill the bioabsorbable void. Longer follow-up or postmortem histological studies may reveal some bony tissue formation in the implant site. A long-term in vivo study with a larger number of patients is needed to evaluate degradation pattern and tissue reaction to PLLA-Ds.
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Disclaimer:
Scientific Abstract Monthly postings are submitted by podiatric surgical residents. The ideas presented are not the opinions of the American College of Foot and Ankle Surgeons (ACFAS), nor are they presented as facts. ACFAS presents this information without any warranty of any kind, expressed or implied, and is not liable for its accuracy nor for any loss or damage caused by the user's reliance on information obtained in these areas.