Knee Arthritis:  How Physical Therapy Can Help

Osteoarthritis is a condition where the protective cartilage of the joint surfaces breaks down.  The cartilage serves as a pad or cushion to the bone beneath it.  The knee, hip, and spine are the most joints where osteoarthritis develops.  In the knee, this can occur on the end of the thigh bone (femur), the lower leg bone (tibia), or both.   Arthritis can also be present underneath the knee cap.   When the cartilage wears away, the body responds by laying down additional bone.  This results in spurs and narrowing of the joint space.

knee arthritis

Knee arthritis is not always associated with pain.  Also, “severe” arthritis viewed on x-rays may result in only mild pain.  Likewise, mild arthritis may result in higher levels of pain.  The experience of pain is complex.  Joint inflammation, joint stiffness, muscle weakness, muscle tightness, and changes within the nervous system can all contribute to pain experienced from arthritis.

Symptoms of Knee Arthritis

Knee arthritis typically affects people over 50 years of age, although it can be present in younger people.  It is more common in females.   Common symptoms include stiffness early in the morning or when initiating walking after prolonged sitting.  Pain, stiffness, weakness, and cracking or popping sounds are hallmark signs.  The pain is generally worse with weight-bearing activities (e.g., walking, standing, or twisting).  Most people experience “flare-ups” of increased pain and stiffness interspersed with periods of little or no pain.

Physical Therapy for Knee Arthritis

Recent research shows several types of exercise are effective for improving pain and function in people with knee arthritis.  This includes aerobic exercise, strengthening exercise and stretching.

knee arthritis

Aerobic exercise for people with arthritis is backed bys solid research. Regular walking for 30 minutes five days per week is recommended.  Continuous walking is preferred but if a person is unable to perform one 30-minute walk, multiple shorter walks totaling 30 minutes can be employed.  Physical therapists help patients begin and progress an individualized walking program.  Cycling, swimming, and other forms of aerobic exercise can also be incorporated.  However, walking programs show the greatest improvements.

An individualized muscle strengthening program is prescribed for patients with knee arthritis.  The quadriceps and hip muscles are targeted.  These muscles are important for walking, climbing stairs, and transferring from sitting to standing.  Weakness of the quadriceps muscle on the front of the thigh is common in people with knee arthritis.  Strengthening both the quadriceps and hip muscles has been shown to produce the greatest improvements in walking ability.   Sit to stand training is an excellent way to incorporate both of these muscle groups.

Knee arthritis results in stiffness of the joint capsule and ligaments.  The surrounding muscles shorten further limiting range of motion.  Stretching exercises to improve knee straightening (extension) range of motion is important to restore normal walking patterns.  Manual therapy performed by a physical therapist is often needed to achieve sufficient improvements in people with longstanding stiffness.  Manual therapy may be incorporated at the knee, hip, ankle, or spine joints.  This is because problems at the knee are often associated with problems at neighboring joints.

Closing Thoughts

Knee arthritis does not have to be a disabling condition.  Exercise can be very effective for improving pain, function, and quality of life.  Many people are unsure how to start and what type of exercise is best for their goals.  Meet with your physical therapist to develop an individualized exercise program that meets your needs.


  1. Goh SL, Persson MSM, Stocks J, et al. Relative efficacy of different exercises for pain, function, performance and quality of life in knee and hip osteoarthritis: Systematic review and network meta ‑analysis. Sport Med. 2019;49(5):743-761.
  2. Hislop AC, Collins NJ, Semciw AI, Tucker K, Deasy M. Does adding hip exercises to quadriceps exercises result in superior outcomes in pain, function and quality of life for people with knee osteoarthritis? A systematic review and meta-analysis. Br J Sports Med. 2019;0:1-10.


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