Kirschner Wires Versus Cannulated Screws in Minimally Invasive Chevron-akin Osteotomy for Hallux Valgus: A Two-year Randomised Controlled Trial
In a two-year randomized controlled trial comparing minimally invasive Chevron-Akin osteotomy for hallux valgus, Kirschner wire fixation demonstrated shorter operative times and slightly higher AOFAS scores compared to cannulated screws, while both methods yielded similar long-term radiographic corrections, pain relief, and complication rates.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The human foot is a complex structure of bones, joints, and ligaments that allows us to walk, run, and stand with balance. Over time, a common deformity can develop where the big toe drifts outward toward the smaller toes, while the base of the big toe pushes inward, creating a prominent bump on the side of the foot. This condition, known as hallux valgus, can cause significant pain and make it difficult to wear shoes. For decades, surgeons have used various techniques to cut and realign the bone to fix this problem. In recent years, a shift toward minimally invasive surgery has gained popularity. Instead of making a large incision to expose the entire foot, surgeons use tiny cuts and specialized tools to perform the correction from the outside. This approach generally leads to less scarring, less pain after the operation, and a quicker return to daily life. However, once the bone is cut and moved into the correct position, it must be held steady while it heals. The critical question for surgeons has been how best to hold that bone in place: should they use strong metal screws that stay inside the body, or thin metal wires that are removed after a few weeks?
A team of researchers in Brazil set out to answer this question with a rigorous comparison. They recruited adults suffering from moderate to severe cases of this foot deformity and randomly assigned them to one of two groups. One group received the standard treatment using two small, hollow metal screws to lock the bone in place. The other group received a different approach using two thin metal wires, known as Kirschner wires, which were inserted through the skin and buried just beneath the surface. The wires were designed to be removed in a simple procedure six weeks later, whereas the screws were intended to remain permanently. The researchers followed these patients for two years, checking their pain levels, their ability to walk, and the position of their bones using X-rays. They wanted to see if the cheaper, removable wires could perform just as well as the more expensive, permanent screws, or if the screws offered a necessary advantage in stability and safety.
The results of this two-year study showed that both methods worked very well. Patients in both groups experienced a dramatic reduction in pain and a significant improvement in how their feet looked and functioned. By the end of the study, the vast majority of people in both groups were highly satisfied with the outcome, with most rating their results as excellent. The X-rays confirmed that the bones had healed in the correct position for everyone, regardless of which metal was used to hold them. The deformity was corrected, and the angles of the foot returned to a normal range. There was no evidence that one method led to a higher rate of the bone failing to heal or the deformity returning. In fact, the study found that the pattern of recovery was nearly identical for both groups, with the most significant improvements happening within the first year and remaining stable through the second year.
While the overall success was the same, the study did reveal some practical differences between the two approaches. The surgeries using the thin wires took less time to perform, averaging about twenty-two minutes compared to nearly twenty-eight minutes for the screw group. This difference, while small, suggests that the wire technique is slightly faster. More notably, the study observed a higher number of complications in the group with the permanent screws. Several patients in that group developed pain because the metal screws were prominent under the skin, causing discomfort that required a second, minor surgery to remove them. In contrast, the group with the wires had very few complications, with only one patient experiencing a specific nerve-related pain issue that resolved with treatment. No infections occurred in either group, which is a significant finding given that the wires were buried under the skin rather than left sticking out, a technique that typically carries a higher risk of infection.
The researchers concluded that both fixation methods are safe and effective for correcting this foot deformity. The study suggests that the choice between using permanent screws or removable wires does not need to be driven by a fear that one is inferior to the other in terms of long-term healing or pain relief. Instead, the decision can be based on other factors, such as the availability of specific medical supplies, the cost of the implants, and the surgeon's experience. For healthcare systems with limited resources, the study provides strong evidence that the wire method is a viable, cost-effective alternative that does not compromise the quality of the patient's recovery. Ultimately, patients can be reassured that whether they receive screws or wires, the goal of a pain-free, well-aligned foot is achievable with either technique.
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