Broken Legs and Ankles Heal Better If You Walk on Them within Weeks
Using crutches for months is largely a thing of the past. Early weight-bearing has real benefits
Twenty years ago my husband, Mark, broke his left ankle and was in a cast and on crutches for nearly two months. Last year he broke the other ankle. But this time, after surgery, his doctor surprised us by instructing Mark to walk on it two weeks later.
It turns out the standard advice to stay off a broken leg bone for at least six weeks is based less on scientific evidence and more on cultural caution—physicians like to play it safe. But now studies show that complications are no more likely with early weight-bearing than with a long delay. Except in a few complex cases, walking around earlier helps broken bones heal, and it improves quality of life: for example, people can return to work and other activities faster.
If you are fully immobilized, “you come out of the cast with a sort of hairy, withered leg that takes forever to overcome,” says orthopedic trauma surgeon Alex Trompeter of St. George’s University of London. “The science tells us that the rate at which you lose muscle mass is far faster than the rate at which you gain it.” You’re slow to build bone, too. Consider astronauts. After six months in zero gravity at the International Space Station, they lose 10 percent of their bone density, and to ward off that loss they do exercises in space that are equivalent to bearing weight.
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In the 19th century German surgeon and anatomist Julius Wolff recognized that healthy bones adapt and change in response to the load placed on them. That is why everyone—but especially women, who are more susceptible than men to osteoporosis—should lift weights as they age. It increases bone density.
Those who walked early on femurs that had broken just above the knee had no higher rate of complications than those who stayed off the leg for six weeks.
When you fracture a bone anywhere in the body, physicians first worry about stability. How much will the bone fragments move if you put weight on them? If the answer is too much, surgery is usually indicated—first a “reduction” to realign the pieces of bone and then “fixation” to hold them in place with screws, plates or rods.
That procedure sets up a bone, which is living tissue, to heal naturally by making new bone and resorbing damaged cells. In the gap caused by a fracture, a healing tissue called callus forms first, which then turns into bone. The right amount of load or movement (here’s where Wolff’s discovery applies) is critical to this process. Too little results in no callus; too much prevents the bone from knitting back together. “It’s all about the strain environment,” says orthopedic surgeon Chris Bretherton of Queen Mary’s Hospital in London.
Surgical implants hold the alignment until that process is complete. “It’s a little bit of a race postoperatively between the bone healing and the fixation breaking,” says orthopedic trauma surgeon Marilyn Heng of the University of Miami Miller School of Medicine. In that contest, she roots for the new bone. “Once the body heals and forms bone across the fracture site, the hardware we put in becomes extraneous. The crux of our decisions for weight-bearing status is we want to win that race.”
And putting some load on the bones aids that goal. Although the process of bone healing is the same all over the body, bones in the lower limbs such as hips, femurs and ankles bring extra complications because they affect the ability to walk. In patients with hip fractures—predominantly frail, older people—that immobility can lead to dire consequences.
Breaks in long bones, like the femur in your thigh, can be relatively straightforward to repair with a rod. In a study that looked back at outcomes for a series of patients, Heng and her colleagues showed that those who walked early on femurs that had broken just above the knee had no higher rate of complications than those who stayed off the leg for six weeks.
For ankles, the largest randomized controlled trial to date (480 fracture cases across 23 centers in the U.K.) was published in 2024 in the Lancet. Half of the patients were instructed to walk after two weeks, and the other half were told to wait until after six weeks. Any complications, such as infections or broken plates, were equally common in both groups, so early walking didn’t pose a greater risk. And the early weight-bearing group reported better function in the ankle at six weeks and at four months postsurgery. “Surgeons just needed a push,” says Bretherton, who led the study. He hopes this evidence “gives them that confidence.”
As for my husband, he jumped at the chance to get moving sooner. In less than two months, the point at which he was just coming out of a cast last time, his scar was fully healed, he was walking normally and, with a few limitations—no running, no quick pivots—he was exercising again. It seems that he won this race.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.
Lydia Denworth is an award-winning science journalist and contributing editor for Scientific American. She is author of Friendship (W. W. Norton, 2020).
Source: www.scientificamerican.com