Bob's ACL WWWBoard On-Line Knee Library |
Click here to return to the subsection ACL Reconstructions via Patellar Tendon Autografts.
Click here to return to the subsection Revision Reconstructions: Factors behind ACL-Graft Failures, Outcomes.
------
Document Title: Drogset-AJSM-Jul06.shtml
Article Title:
Magnetic Resonance Imaging Analysis of Bioabsorbable Interference Screws Used for Fixation of Bone–Patellar Tendon–Bone Autografts in Endoscopic Reconstruction of the Anterior Cruciate Ligament
Authors: Jon Olav Drogset, MD*,, Torbjørn Grøntvedt, MD, PhD and Gunnar Myhr, MD
Publication: American Journal of Sports Medicine, Baltimore, Maryland
Date: July 2006
Volume 34, pages 1164-1169
Keywords: ACL, anterior cruciate ligament, patellar tendon autograft reconstruction, bioabsorbable interference screw, polylactic acid, poly-L-lactic acid, poly-levoro-lactic-acid, resorption, MRI, magnetic resonance imaging, NMR imaging.
(Reference-denoting numbers appear in the same font and point size as the document text. As with all Knee Library documents, this article is provided in full-text form, complete with all figures and tables.)
Comments: These authors, who in a previous study found that metal interference screws are preferable to bioabsorbable ones, found that at 24 months post-op, volumetrically one-third of a bioabsorbable screw remains. The concerns with bioabsorbable screws are tunnel widening, formation of fluid pockets, and osteolysis; however, symptoms of problems are rare. And fortunately, the security and dependability of bone-to-bone healing, an advantage unique to the patellar-tendon autograft due to the bone plugs at both ends, remains. But if the person requires an ACL revision reconstruction, then the aforementioned concerns should be kept in mind. It should be kept in mind that, in the event of revision reconstruction being needed, metal interference screws can present problems too: the hardware might have to be removed, and bone-grafting done, before the revision itself can proceed. (Once again, we see the importance of doing ACL reconstruction correctly the first time. The major cause of graft failure is surgeon error, usually in the form of mis-placed bone tunnels. However, reinjury is distressingly common. Common causes of reinjury are failure to follow the rehabilitation protocol, failure to learn to pivot on only the front portion of the foot, and contact-type situations such as sideways forcing and injurious hyperextension.)
ABSTRACT
Background: Metal interference screws can cause problems if revision is needed and can interfere with magnetic resonance imaging. Bioabsorbable screws have been developed to prevent these problems, but the rate of resorption and integration is not well understood.
Hypothesis: Poly-L-lactic acid interference screws will be resorbed 2 years after anterior cruciate ligament reconstruction.
Study Design: Case series; Level of evidence, 4.
Methods: The study group consisted of 19 patients with isolated anterior cruciate ligament ruptures reconstructed with bone–patellar tendon–bone autografts fixed with poly-L-lactic acid interference screws using an endoscopic technique. Magnetic resonance imaging was used to evaluate resorption of the screws, bony integration of the screws, and integration of the bone blocks after 2 years.
Results: At 2 years, the mean reduction in the volume of the femoral screws was 64% and of the tibial screw was 63%. Bony integration of the femoral bone block was considered good in 17 patients and fair in 2 patients. Integration of the tibial bone block was considered good in 16 patients and fair in 1 patient who demonstrated widening of the tibial tunnel. Osteolysis around the screws was seen in 3 patients in the femur and none in the tibia.
Conclusion: The mean reduction in volume of the poly-L-lactic acid screws as measured by magnetic resonance imaging after 2 years was approximately two thirds. The integration of the bone blocks was considered good in 90% of the patients. Osteolysis around the screws was visible in 16% of the patients.
Clinical Relevance: Two years after ACL reconstruction using poly-L-lactic acid interference screws, the surgeon can expect to find approximately one third of the volume of the screw remaining in the bone tunnels.
To access the full text of this article, please click here.
There is no charge for viewing articles. However, a password is required.
If you do not already have a password, please e-mail Michael Frind at frind@execulink.com for one.
Prior to requesting a password, please make certain you have read the
Site Terms of Use
pertaining to this site.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Copyright American Journal of Sports Medicine, American Orthopaedic Society for Sports Medicine, July 2006. For details regarding copyright as it applies to this page, please visit the page entitled Site Terms of Use and Aspects of Copyright on this site.
This website was created for the benefit of the world's largest knee-injury community, Bob's ACL WWWBoard (also known as the Kneeboard), accessible to everyone at http://factotem.org.
Documents posted on this site serve merely as a virtual library, and are intended solely for purposes of making access to high-quality peer-reviewed medical-journal articles convenient for all users of the Kneeboard. Knee-injury patients are hereby encouraged to discuss this material with their respective medical teams.
Click here to return to the Main Entrance Page of the Knee Library.
Looking for the Main Index Page of Bob's ACL WWWBoard? Click here!
To find recent postings on Bob's ACL WWWBoard, use the Search Engine.
To find older postings on Bob's ACL WWWBoard, use the On-Line Archive.
Site Terms of Use and Aspects of Copyright