Single-Incision Dual Intramedullary Fixation of Floating Knee Injuries: A Retrospective Case Series

When a high-speed car crash or a severe fall strikes the human body, the force can be so immense that it shatters the two long bones of the leg at the same time: the thigh bone and the shin bone. In medical terms, this is called a "floating knee." Because the knee joint is no longer anchored by either bone, it hangs loose, unable to bear weight or protect the limb. These injuries are rare but devastating, often accompanied by damage to muscles, skin, and blood vessels. The standard way to fix this has long been to perform two separate surgeries, one for the thigh and one for the shin, using different cuts in the skin to insert metal rods into the hollow centers of the bones. While effective, this approach requires cutting through already injured tissue in two places, which can slow down healing and increase the risk of infection.

A team of surgeons at Christian Medical College in Vellore, India, explored a different path. They asked whether it was possible to fix both broken bones through a single, small opening in the front of the knee. By splitting the tendon that connects the kneecap to the shin bone, they could reach the entry points for both the thigh and shin rods without making a second cut. This method promises to spare the patient more trauma and speed up recovery. However, because these injuries involve such severe damage to the body's natural healing systems, the surgeons needed to know if this clever shortcut actually worked as well as the traditional method, or if the bones would struggle to knit back together.

The researchers looked back at the records of seven patients treated between 2010 and 2020 who had suffered these specific double fractures. All of them were adults, with an average age of just over thirty years, and all had been treated using this single-incision technique. The surgical team placed the patients on their backs, bent the knee to a comfortable angle, and made one vertical cut right down the middle of the front of the knee. They carefully split the tendon fibers apart to create a tunnel. First, they guided a metal rod up through the knee joint and into the broken thigh bone, locking it in place. Without closing the wound, they then directed a second rod down from the same opening into the broken shin bone. Once both bones were stabilized with metal rods, they meticulously stitched the tendon back together and closed the skin.

The results of this approach were a mix of technical success and biological reality. The single cut did indeed allow the surgeons to fix both bones without adding extra scars to the injured leg. The patients were able to begin moving their knees again, with most achieving a bend of over one hundred degrees within six months. However, the severity of the original injury proved to be a stubborn obstacle. While the shin bones healed in most cases, taking an average of ten months to fuse, the thigh bones told a different story. In three out of the seven patients, the thigh bone simply refused to heal, a condition known as non-union. This happened in nearly half of the group, forcing them to undergo further surgeries to try to get the bone to knit. One patient, who had an open fracture where the bone pierced the skin, developed a deep infection that required removing the metal rod and switching to a different type of external frame to stabilize the leg.

The study did not find that this single-cut method was a miracle cure that eliminated the risks of such severe trauma. Instead, it showed that while the technique is feasible and saves the patient from multiple incisions, the high-energy nature of the crash itself often dictates the outcome more than the surgery does. The patients who healed well reported good quality of life, but the high rate of thigh bone non-union suggests that the body's ability to repair itself in these cases is severely compromised. The researchers concluded that while this method is a valid option that avoids cutting the skin twice, it does not guarantee a smoother recovery. Surgeons using this technique must be prepared for the possibility that the bones may not heal on their own and that additional interventions will likely be needed. Until larger studies compare this approach directly against the traditional two-cut method, the single-incision technique remains a useful tool in the surgeon's kit, but one that requires careful management of expectations and a readiness to address complications as they arise.