Biodegradable Screws: An Effective Alternative to Metal Screws?
Stener S, Ejerhed L, Sernert N, Laxdal G, Rostgard-Christensen L, Kartus J
Am J Sports Med. 2010;38:1598-1605.
Biodegradable anterior cruciate ligament (ACL) graft fixation screws are being utilized with increased frequency in ACL reconstruction as orthopaedic surgeons look for an alternative to metal interference screws. Metal screws have been associated with adverse events, including MRI distortion and complications in revision surgery. Despite an increased interest in biodegradable fixation screws, there have been few comparative clinical studies comparing them to metal screws.
In the randomized controlled study performed by Dr. Stener and colleagues, 77 patients underwent unilateral ACL reconstruction surgery using hamstring tendon autografts with either poly-L-lactide acid (PLLA) or metal interference screw fixation. Patients were then re-evaluated 8 years later with radiographic imaging and clinical measurements, including Tegner activity level, Lysholm knee score, single-legged hop test, early C-reactive protein response, and KT-1000 arthrometer knee laxity measurements.
In comparison with the metal interference screw group, the PLLA group was found to have larger bone tunnels on the femoral side (11.4 mm vs. 8.0 mm, P < .005) but not on the tibial side. No statistically significant differences were noted in other clinical measures.
The medical literature to date has shown similar clinical results between metal and PLLA interference screw fixation. However, PLLA screws have been associated with other complications, including tunnel enlargement, higher graft failure rate, screw breakage, and variable bone incorporation post-implantation. Consideration of other metrics, such as evaluation of ACL graft bundle integrity, comparative graft failure rates, as well as rate of osteoarthritis development, in future studies may be helpful in delineating other clinically significant differences, particularly with the use of newer composite implant technology.
Abstract
A Long-term, Prospective, Randomized Study Comparing Biodegradable and Metal Interference Screws in Anterior Cruciate Ligament Reconstruction Surgery: Radiographic Results and Clinical Outcome
Stener S, Ejerhed L, Sernert N, Laxdal G, Rostgard-Christensen L, Kartus J
Am J Sports Med. 2010;38:1598-1605.
Summary
Biodegradable anterior cruciate ligament (ACL) graft fixation screws are being utilized with increased frequency in ACL reconstruction as orthopaedic surgeons look for an alternative to metal interference screws. Metal screws have been associated with adverse events, including MRI distortion and complications in revision surgery. Despite an increased interest in biodegradable fixation screws, there have been few comparative clinical studies comparing them to metal screws.
In the randomized controlled study performed by Dr. Stener and colleagues, 77 patients underwent unilateral ACL reconstruction surgery using hamstring tendon autografts with either poly-L-lactide acid (PLLA) or metal interference screw fixation. Patients were then re-evaluated 8 years later with radiographic imaging and clinical measurements, including Tegner activity level, Lysholm knee score, single-legged hop test, early C-reactive protein response, and KT-1000 arthrometer knee laxity measurements.
In comparison with the metal interference screw group, the PLLA group was found to have larger bone tunnels on the femoral side (11.4 mm vs. 8.0 mm, P < .005) but not on the tibial side. No statistically significant differences were noted in other clinical measures.
Viewpoint
The medical literature to date has shown similar clinical results between metal and PLLA interference screw fixation. However, PLLA screws have been associated with other complications, including tunnel enlargement, higher graft failure rate, screw breakage, and variable bone incorporation post-implantation. Consideration of other metrics, such as evaluation of ACL graft bundle integrity, comparative graft failure rates, as well as rate of osteoarthritis development, in future studies may be helpful in delineating other clinically significant differences, particularly with the use of newer composite implant technology.
Abstract
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