Platelet-Rich Plasma (PRP) is an autologous blood product, meaning it comes from the patient’s own body, which is processed to concentrate platelets and growth factors far above normal blood levels. This concentrated solution is injected into the knee to stimulate tissue repair and accelerate the body’s natural healing process for orthopedic conditions like osteoarthritis, meniscal tears, and ligament injuries. The question of walking after a PRP injection into the knee is a common concern, as post-procedure activity directly influences the treatment’s success. The purpose of recovery protocols is to protect the newly injected plasma, ensuring the platelets can anchor and initiate the necessary cascade of growth factor release. Understanding the specific limitations on movement immediately afterward is paramount to maximizing the regenerative potential of the treatment.
Immediate Post-Injection Activity Restrictions
Immediately following a knee PRP injection, activity must be severely limited to avoid disrupting the injected plasma and diluting the concentration of growth factors. For the first 24 to 48 hours, patients are typically instructed to rest and avoid any strenuous activity. The goal is to allow the platelets time to activate and release their reparative factors into the targeted tissue, which is a process that can be hindered by excessive mechanical stress.
The use of assistive devices, such as crutches or a cane, is often recommended for lower extremity injections, particularly if the injection targeted a ligament or tendon rather than the joint space itself. While some protocols allow weight-bearing as tolerated (WBAT) for intra-articular joint injections, others may advise partial or non-weight-bearing status to minimize load on the treated area. It is important to follow the specific instructions of the treating physician, as the level of restriction can vary depending on the exact location of the injury and the volume of plasma injected.
Even if walking is technically possible, prolonged standing and excessive movement should be avoided immediately after the procedure. Light, gentle range-of-motion exercises may be encouraged to prevent stiffness, but any activity that causes pain or strain should be stopped. Elevating the knee when resting is also a standard recommendation to help manage potential swelling at the injection site. Limiting movement during this initial window ensures the concentrated platelets remain localized to the area where healing is needed most.
Managing Pain and Inflammation in the First Week
It is normal to experience a temporary increase in pain, swelling, and stiffness in the knee within the first few days after the PRP injection. This discomfort is actually a sign that the body’s inflammatory response has been successfully triggered by the platelet growth factors, which is a necessary step for tissue regeneration. This inflammatory phase typically peaks between 2 to 5 days post-injection as the body begins its repair work.
The most significant restriction during this phase involves medication, specifically the avoidance of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as ibuprofen, naproxen, or aspirin. NSAIDs interfere with the inflammatory cascade and can counteract the therapeutic effect of the PRP, which relies on a brief inflammatory period to initiate healing. Patients are usually advised to avoid these drugs for at least one to two weeks, and sometimes longer.
For managing post-injection pain, Acetaminophen (Tylenol) is the approved over-the-counter analgesic because it does not interfere with the inflammatory process. The use of ice or cold therapy is often limited or discouraged entirely during the first 48 to 72 hours, as excessive icing may also dampen the necessary inflammatory signal. If ice is permitted, it should be applied only intermittently for short durations to the surrounding area for comfort, rather than directly to the injection site for prolonged periods.
Gradual Return to Physical Therapy and Full Activity
The transition from restricted mobility to structured rehabilitation begins once the initial intense inflammatory phase subsides, typically around the one-week mark. At this point, the focus shifts from pure protection to controlled movement to support the healing process. Light walking on flat surfaces is encouraged, as this low-impact activity helps to promote circulation and prevents joint stiffness without undue strain.
Physical therapy is a critical component of the recovery pathway, often starting between two to four weeks after the procedure. The initial exercises focus on restoring the full range of motion and initiating gentle muscle strengthening, particularly for the quadriceps and hamstrings, which stabilize the knee joint. This structured approach ensures that the new tissue being generated by the PRP treatment is guided into a functional, strong configuration.
Low-impact aerobic activities, such as using a stationary bicycle or swimming, can usually be introduced around weeks two to four as the patient tolerates them. High-impact activities that involve running, jumping, or heavy weightlifting must be avoided for a much longer period, often for four to six weeks or more, depending on the severity of the original injury. The ultimate goal of this gradual return is not simply to resume walking, but to strengthen the entire joint structure to sustain the long-term benefits of the PRP injection.