The knee is the largest joint in the body, and for good reason: depending on the activity, it can bear a force equal to roughly five times a person’s weight—and sometimes even more. And while it usually does a pretty good job of sustaining that force, it isn’t totally destruction-proof. In fact, knee pain is one of the most common musculoskeletal issues that physical therapists encounter.
A hinge joint connecting the lower leg to the upper leg, the knee is comprised of four supporting ligaments and a meniscus, which is basically a cartilage cushion that helps absorb shock during activity. The joint is covered by the patella—better known as the kneecap—and surrounded by several supporting ligaments and muscles that keep the knee stable as it moves.
There are actually two separate joints in the knee: the patellofemoral joint connects the thigh bone (a.k.a. the femur) to the patella, and the tibiofemoral joint connects the femur to the shin bone (a.k.a. the tibia).
Most knee problems result from either an acute injury (e.g., falling while skiing and tearing a ligament) or overuse (e.g., running too many miles on hard pavement while training for a marathon). Knee pain can also be a symptom of underlying degenerative conditions (e.g., arthritis).
Types of knee pain include:
- Acute pain (i.e., pain occurring immediately after injury)
- Sub-acute pain (i.e., pain occurring several weeks after injury)
- Chronic pain (i.e., pain that lasts for several months with little to no improvement)
Knee pain may occur in a variety of anatomical locations, including:
- Front: Front knee pain often signifies an issue with the kneecap—patellofemoral stress syndrome, for example. This happens when the tissues under and around the patella become inflamed.
- Inside: Inside knee pain often occurs when the medial meniscus or medial collateral ligament (MCL) are injured or damaged.
- Outside: Outside knee pain often results from injury to the hamstring or iliotibial (IT) band, a thick ribbon of tissue extending from the hip to the front of the knee.
- Back: Pain behind the knee joint is usually a sign that the hamstring is tight or injured. In less common cases, it may result from a Baker’s cyst.
Perhaps one of the most widely known knee injuries is an anterior cruciate ligament (ACL) tear. Common among athletes, ACL tears not only cause pain, but also create a feeling of instability in the knee joint that can prevent patients from moving naturally. In severe cases, patients may require surgery to repair the damaged ligament. In other cases, patients can successfully rehabilitate the injury without surgery.
Speaking of surgery: Anyone undergoing a total knee replacement, or TKR, will be referred to post-op physical therapy to help ensure optimal healing. The PT will help strengthen weak areas and alleviate post-surgical stiffness in order to help the patient move as naturally and functionally as possible. Rehabilitative therapy during this recovery window is crucial. Otherwise, the patient may develop unnatural, inefficient movement patterns that will be difficult to correct and may lead to the development of additional musculoskeletal issues.
Regardless of the diagnosis, knee pain can often be successfully treated by a qualified physical therapist. Once the initial swelling has subsided, the therapist can evaluate the patient’s pain and functional impairment and develop a personalized treatment plan designed to return the patient to his or her normal level of activity.
Physical therapists may use any of the following methods to evaluate knee pain:
- Gait analysis: The PT will observe and assess your gait and stride as you walk and run to identify abnormalities.
- Palpation: The PT will touch and/or test the knee to check for physical abnormalities.
- Range of motion (ROM) tests: The PT will measure flexion and extension to get a better idea of the injury’s severity and which structures it is affecting.
- Swelling assessment: The PT will measure the amount of swelling to help determine where the patient is in the healing process. This helps the therapist set an appropriate timeline for recovery.
- Other tests: The PT may use a number of special tests to help determine and/or confirm the specific diagnosis and identify any underlying or complicating conditions.
Physical therapy care plans for knee-related diagnoses involve a variety of active and passive treatments, including:
- Stretching and flexibility exercises
- Strengthening exercises
- Water aerobics
- Cardio training (e.g., on gym machines designed to reduce impact)
- Hot-cold therapy
- Electrical stimulation
- Dry needling
- Therapeutic massage and other manual therapy techniques
- Joint manipulation/mobilization
Additionally, patients will receive a home exercise program to help promote care continuity in between appointments. The therapist may also recommend using a supportive or assistive device (such as a cane or knee brace) to aid in stabilizing the injured joint as it heals. Total treatment time will vary depending on the type and severity of the injury, but patients should expect to attend therapy several times a week for at least three to six weeks.