- Volume 26 - Issue 1 - January 2013
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A recent study in the Journal of Bone and Joint Surgery notes that biodegradable implants may obviate some of the disadvantages of metallic implants for internal fixation of unstable ankle fractures, such as imaging interference and the need for revisional surgery.
The study included 102 patients with ankle fractures who had surgery with metallic or biodegradable implants. The mean time to bone union was 15.8 weeks in the metallic group and 17.6 weeks in the biodegradable group. The outcomes of using biodegradable implants to fixate isolated lateral malleolar fractures were comparable to those of metal implants, notes the study.
John Grady, DPM, notes that metallic ankle implants are versatile, coming in various shapes and sizes that one can manipulate. He adds that the metallic implants are also radiopaque, long-lasting, less expensive than bioabsorbable implants and have less reactivity. In contrast, Dr. Grady notes that metallic implants can sometimes loosen, requiring removal, and their radiopacity can be a factor in an inability to “see through” the implants. Furthermore, he says metal implants leave defects in bone when removed so this can weaken remaining bone.
As for bioabsorbable implants, Dr. Grady notes they incorporate well to allow or even help bone re-integration, and the implants’ relative radiolucency can be an advantage in checking X-rays without interference. On the downside, he notes that bioabsorbable implants are more reactive, with some materials reacting within the first three months, others years later, but with reactions ranging in the 2 to 3 percent range. He says the implants’ cost is also a disadvantage.
“You can tell from this article that (bioabsorbable implants) are not quite as effective as metallic implants, though not by much,” says Dr. Grady, a Fellow of the American Society of Podiatric Surgeons and the Director of the Podiatric Surgical Residency Program at the Westside Division of the Veterans Administration Chicago Healthcare System.