As the ski season gets into full swing, friends who recently suffered a sprain or had a total hip arthroplasty (THA) (implanted hip prosthesis) are wondering whether they will be able to hit the slopes this year. Did you know that 400,000 American had a THA this past year? How long after a THA must they wait before skiing? And beyond that sport, before they are jogging or biking again? Most doctors offer a conservative approach, allowing for full recovery before pursuing such rigorous sports. Their judgments are based on the average recovery of a large group of patients, throwing in a reasonable safety margin to try to avoid joint deterioration.
If you’ve had to endure the seemingly never-ending recovery period of THA, you’ve no doubt felt the frustration of feeling perfectly fit to go skiing, probably just before the season ended. Too soon, according to doctors’ recommendations. But let’s imagine imagine a more hopeful scenario: that your doctor could evaluate (for you as an individual patient, not an average) whether the risk of injury practicing your favorite sport is indeed real. Will the exercise induce too large a movement between bones and implant, thus preventing proper healing? Would the stress in your weakened ankle be too great, leading to a new injury? Could you at least start some light training again? If only we could estimate the exact stress induced by various movements in the different parts of the body, we would know for sure if we can get back in the game or need to rest further.
Simulation strives to answer these questions. For this case, the process simply requires a scan of your body, which then is used to create a virtual image of your skeleton and muscles. The virtual part consists of applying the proper operating conditions related to the activities you want to practice. But it’s never that simple, is it? There are a lot of roadblocks, such as getting access to a proper scan of your own body, importing patient-specific geometry and material properties into your favorite software, and applying the proper boundary conditions on the skeleton.
Yet, the figure below proves we are getting there, and quickly. Elite athletes are now increasingly using simulation to fine-tune their performances or minimize the risk of injury, such as tennis elbow. The rest of us are next: In a not so distant future, our doctors will be able to give us a much more specific answer, and we’ll know for sure how much more rest we need. How soon the process is available depends on how high the demand for this service will be.