Patellofemoral stress syndrome (PFSS for short) is the medical term used for what most of us call “runner’s knee” and is among the top causes of knee pain. This condition is due to an abnormality of the patellofemoral joint where the patella (kneecap) slides along the femur (thigh bone) during knee movement. Over 40% of all overuse injuries affect the knee joint and PFSS is the leading injury among runners. PFSS is often referred to as "runner's knee" or "jumper's knee" because people who participate in sports—particularly females and young adults—make up the majority of cases but it’s not unusual for PFSS to affect non-athletes as well. Whether you are an avid runner or not, PFSS can make even daily movements like climbing a stairs or squatting uncomfortable, preventing you from doing the activities you love. Most episodes of PFSS get significantly better or completely resolve in about six to eight weeks with the standard R.I.C.E. approach. If your specific condition is more severe it may take a bit longer to achieve pain-free function. PFSS rarely requires surgical intervention, but pushing through the pain can set your recovery back and even lead to more serious issues. When symptoms persist beyond 2 weeks of rest, consulting with a physical therapist should be your next step. Fortunately, with appropriate strengthening and modifications, the vast majority of cases treated with physical therapy resolve and returning to full activity is possible.


Pain associated with PFSS is typically felt in the front of the knee and around the kneecap, ranging from mild to severe discomfort. Initially, many experience a deep ache or sharp pain on either side of the kneecap or on the front of the knee accompanied with stiffness in the joint. In advanced cases some even feel grinding or hear popping in the kneecap. Pain usually begins gradually and is frequently activity-related. The primary signs and symptoms of runner's knee are:

  • Knee swelling. Swelling in the front of the knee may occur, signaling inflammation. Swelling may limit mobility, as well as increased soreness in many cases.

  • Stiffness after rest. Extended periods of having the knee bent, such as driving or sitting at a desk as well as activities that repeatedly bend the knee, such as climbing stairs, running, jumping, or squatting lead to stiffness and exacerbated pain.

  • Pain in the front of the knee. Misalignment of the femoral groove and the patella may cause pain around the front of the knee or the sides of the kneecap. At rest the pain may just be an ache but worsen and/or feel sharp during movement.

  • Knee crepitus. A grinding or crunching sensation within the knee, known as knee crepitus, during certain movements. Extended periods of rest, such as when getting out of bed in the morning will generally make it worse,.

  • Pain worsens when moving. Pain, excess friction, or popping noises with movements like squatting from a standing position or walking uphill. This pain will usually lessen when activity ceases.


Because patellofemoral stress syndrome is the result of repeated movement rather than a single incident or impact, sports that involve a lot of knee bending and straightening, like running, skiing and biking have a high rate of cases. Certain exercises at the gym, such as deep squats, may contribute to this type of knee pain as well. Women tend to develop PFSS more than men, and age is also often a factor with a majority of those being young adults. Weak muscles in the hips and core are generally a contributor because both are responsible for holding the pelvis and thighs in the proper position during movement—when they aren't up to the task, the knees drift inward, driving the kneecap out of alignment. The way your foot strikes the ground with each step can also throw your knee off track, so it's not unusual for there to be weaknesses in muscles that stabilize the lower leg. There are many factors to consider with PFSS and this is why it can be difficult to get rid of without the help of a skilled professional. Physical Therapy for Runner’s Knee

Our goal is to get our patients back to pre-injury status as quickly as possible while also sending them out the door understanding how important alignment and technique is. We want our patients to be more functional and with increased strength so re-injury can be avoided down the road. Identifying the factors that caused the individuals PFSS is the first step we take, then we work to address each factor during the following therapy sessions with a fully customized plan for each individual patient. Glutes and quadriceps muscles can be re-educated so that stress on the knee is reduced during load. An unstable pelvis can become supported by integrating the deep core work using Pilates. Poor biomechanics can be improved by strengthening as well as adjusting footwear. Inflammation can settle and allow for the therapy to take effect with recommended rest and activity changes. Manual soft tissue work like ASTYM or dry needling can release adhensions that are compromising ideal range of motion. Each case is unique, so coming in for a one-on-one initial evaluation with one of our physical therapists would be ideal to help treat that achy sore knee!