One of the most frequent questions that I am asked is "How long will this take to heal" or "How long until I can run / play tennis/ cheer again?" It's the million dollar question, and could be answered with a PT's favorite, trusty response - "It depends."
And really, it does depend, on a lot of things. Are you getting enough sleep and proper nutrition to support healing? Have any underlying issues like low energy availability, irregular lab values, or medical diagnoses like autoimmune disorders been addressed? Are you modifying activity or deloading the affected area as prescribed? These all have a large impact on how quickly you can return to activity from an injury. However, outside of these variables, tissue healing in regular conditions follows a more predictable path and we can estimate when the affected tissue will be ready for certain loads.
Tissue healing varies by the type of tissue: bone, muscle, cartilage, nerve, ligament, or tendon; and the severity of the injury. The table below from Cambridge Osteopathy depicts how timelines vary.
Why are the healing times different for different injuries? Blood flow is a major reason. Bones and muscles generally have good blood supply, and therefore heal more quickly and predictably than a tendon or ligament.
Within these projected healing times, are three distinct phases of healing, outlined below. These healing phases dictate how much load should be applied, and correlate with return to sport.
Inflammatory phase: This occurs over the first hours to days after injury. In this phase, vasodilation and vascular permeability increase to allow inflammatorty proteinsto the site of injury. Vasodilation leads to the increased warmth and redness around an injured area as blood flow increases to carry away dead cells, and increased vascular permeability casues swelling, which inhibits muscle function. White blood cells and inflammatory cells reach the injured tissue through the blood vessels, and initiate the healing process. During this stage, the tissues are very weak, and must be protected from excess strain. The inflammatory phase is important in the healing process, but can be problematic if it persists longer than expected (usually one week).
Proliferation: This phase is when tissue repair occurs, and begins several days after injury, lasting for weeks to months. New cells, blood vessels, and extraccellular matrix begin to fill in the injury, while inflammatory cells decrease. The collagen building blocks of connective tissue are laid down as framework and followed by the appropriate extracellular matrix to host specific cells so that collagen matrix can become the correct type of tissue - cartilage, tendon, bone etc. Exact steps of repair varies by tissue type. During initial repair, the new collagen fibers are disorganized, so they can begin to take on load, but are weak.
Remodeling: This phase improves upon the the collagen laid down during proliferation. This occurs from months to years after inital injury. In this phase, the tissues respond to load and adapt based on stress. For instance, with loading disorganized collagen structures in a tendon begin to realign based on tension lines, to better handle forces. Bone increases strength in a similar way. During this phase, cells with the function to breakdown structures might whittle down on excess scar tissue produced in the initial healing. This is the phase where we want to progressively increase load on the injured structure in order to regain its prior level of functioning for full return to activity.
Healing from an injury can be a lengthy, and frustrating, process. Having a healthcare team including a physical therapist who knows how to guide you through proper exercise progression in order to safely return to sport is key to full recovery, and future injury prevention.
I hope that this helped you understand your recovery from an injury a little better! Thanks for reading!
Dr. Elizabeth Karr PT, DPT
References:
Comments