Stiff Knee – Causes, Treatment & Exercises
Under certain situations, the knee may become resistant to movement, and this may present with severe pain. A stiff knee is always a result of problems related with the structure of the knee joint or its adjoining muscles.
Depending on what causes stiff knee, there may be other associated symptoms such as warmth, redness, tingling sensation, and swelling of the knee.
This article discusses the various causes of the stiff knee, as well as treatment options and tips to prevent it.
Causes of Stiff Knee
There are two broad causes of the stiff knee: Knee injury and chronic inflammatory diseases of the knee.
The knee joint is a hinge joint comprising of the adjoining or articular surfaces of the thigh bone, the shin bone and the patella, ligaments which keep the bones in place, hyaline cartilages that line the articular surfaces of the adjoining bones protecting them and making them glide easily over each other, and menisci which stabilize the knee. Injuries to any of these structures which make up the knee would cause it to stiffen.
Knee injury causes knee stiffness through the following mechanisms;
Fluid accumulation – When there is damage or injury to the knee, an acute inflammatory process is triggered and this causes swelling due to the collection of fluid inside the joint space.
The severity of fluid collection within the joint space is in direct correlation to the severity of the injury.
Severe injury may also cause damage to some blood vessels around and within the knee joint causing hemarthrosis, bleeding into the joint.
Whichever case, the collection of fluid or blood within the knee joint impedes on the gliding of the articular bones, causing stiffness.
Altered Biomechanics – When one of the structures in the knee is damaged, it affects the function of the other structures causing an overall reduction in knee function.
The mechanics and series of movements within the joint which enable knee and leg movement become altered and over time, the compensatory mechanisms put up by the other structures may be overwhelmed and the knee becomes stiff.
Pain – Pain triggers locking of the knee. This is a result of spasm and tightening of the joint muscles in an attempt to protect the knee from more pain and further damage.
Over time, recurrent knee locking and weakness of the muscles from it may cause it to stiffen.
The following knee injuries are common causes of a stiff knee.
- Meniscus Injury: Damage to the meniscus commonly by trauma is a common cause of knee stiffness. Meniscal tear may cause the torn cartilage to wedge within the knee joint preventing full and optimal gliding of the knee articular surfaces over each other.
- Ligament Sprain – A ligament sprain occurs if it is overstretched as a result of sudden sharp movement of the knee, overuse, or an acute injury. Ligament sprain reduces the stability of the joint and swelling within the joint, impeding its movement.
- Ligament Injury – Severe injuries to the anterior and posterior cruciate ligaments often cause hemarthrosis which limits gliding of the bones over themselves.
- Fracture – Fracture may cause the release of bone fragments into the joint space, causing misalignment and instability of the joint machinery, as well as pain. These factors cause locking of the knee and its subsequent stiffness.
- Tendonitis – Inflammation or degeneration of tendons attached to the knee due to trauma or overuse often tighten the joint, making it stiff.
- Arthrofibrosis – This is a rare condition characterized by an excessive formation of scar tissue within structures of a joint after trauma or as a complication of surgery. Excess scar tissue lowers the efficiency and mechanics of the knee joint, making it stiff.
- Exercise – Although this may not be regarded as a pathologic cause, exercise especially strenuous exercise may cause the overworked muscles to tighten and weaken making the knee stiff. This often occurs if the thigh muscles are not properly stretched or warmed up before engaging in the exercise.
Chronic Inflammatory Diseases of the Knee
The following are common inflammatory diseases of the knee that may cause it to stiffen.
Rheumatoid arthritis is a chronic immune-related inflammatory disease of the joints.
It causes damage to the cartilages, which exposes the articular surfaces of the joints to glide over themselves, eventually damaging them.
Rheumatoid arthritis usually affects multiple joints, especially the wrist, knee, and foot joints.
Damage to these structures reduce the stability of the joint, cause swelling within the joint, and cause friction and rigidity of the machinery of the joint, and severe pain which may tighten the muscles moving the knee.
All of these impede free movement of the structures of the joint
Osteoarthritis – Osteoarthritis is a degenerative disease of a joint caused by wear and tear of the structures within a joint from overuse.
It is often related to advancing age and has some genetic associations as well.
In osteoarthritis, the joint surfaces lose its smoothness and the joint space reduces impeding movement of the joint.
Knee Osteoarthritis presents with a stiffness of the knee in the morning and after prolonged rest. This stiffness often resolves with activity.
Gout – Gout is a chronic inflammatory disease of a joint caused by deposition of uric acid crystals within the joint.
The inflammation causes damage to the cartilage and joint surfaces impeding the mechanics of joint movement and causing stiffness.
Bursitis – The bursa is a fluid-filled sac in the joint located between a tendon and a bone. There is a bursa just behind the patella where tendons from the thigh muscles attach.
Injuries or overuse of these muscles and tendons may cause inflammation of this bursa, called prepatellar bursitis. This causes pain and a reduced mobility of the tendons, causing the knee to stiffen.
Signs and Symptoms
The above-listed diseases may present with other symptoms including warmth, redness, and swelling of the knee as in injuries and acute inflammatory conditions of the knee such as bursitis, ligament sprain, and injury.
Gout presents with severe hot sensation in the knee, and chronic inflammatory diseases may also present with occasional swelling as well as the reduced range of motion of the knee.
Treatment of Knee Stiffness
Conservative treatment often helps relieve stiffness of the knee within a few days of its application. Conservative management of knee stiffness includes the PRICE protocol, physical therapy, postural adjustments, and use of analgesics;
The PRICE protocol
- Protection: You use assistive devices such as a knee brace or splint to protect the knee from further damage.
- Rest: In the early stages of a knee injury, rest is very critical in ensuring the damaged structures heal. If the injured knee is exposed to too much activity, it may cause further damage to the knee, as well as new smaller injuries which may aggravate the situation.
- Ice Compresses: This is also called Ice therapy, cold therapy, or cryotherapy. It is a cheap and simple treatment modality for musculoskeletal injury.
Application of ice on the knee after injury reduces inflammation and knee stiffness by reducing pain, reducing spasm of the knee muscles, reducing the risk of death of tissues in the joint by lowering the metabolic rate, and by decreasing the amount of bleeding into the joint by constricting the blood vessels,
You should apply ice crushed in a bag and wrapped in a damp towel to the injured site. Applying the ice directly on the skin may cause “Ice burn”. Additionally, ice should not be applied for longer than 15 minutes each time.
- Compression – Applying pressure to an injured area reduces the swelling that comes with an injury or acute inflammation. Compression achieves this by constricting the blood vessels in the joint thereby reducing bleeding and fluid collection associated with acute inflammation.
Compression may be achieved by applying a compression bandage around the knee. It is essential to note that compression applied to the injured area should not be too tight to prevent compression symptoms such as tingling sensation in the leg, ankle swelling, and in severe cases pallor of the legs. These result from compromised blood supply from tight compression of the knee.
- Elevation – Elevation makes use of gravity to drain fluid accumulating on the injured site, therefore reducing the swelling around the knee joint. For knee stiffness resulting from a knee injury, the knee should be elevated above the hip.
The PRICE protocols are effective when applied within the first 24 to 72 hours of injury to control the acute inflammation. These methods are often very effective at resolving knee stiffness.
There are a number of knee stretches and strengthening exercises which make the thigh muscles strong and flexible enough to move and stabilize the knee.
These exercises build great muscle strength that reduces the stiffness of the knee.
Examples of these exercises include;
Straight Leg Lift
This is done in the following steps;
- Lie on your back with your right leg straight out and your left leg bent at the knee so that your foot touches the floor
- Slowly lift your right leg off the floor till your thigh muscles stretch strongly
- Hold this position for a few seconds, then drop your foot
- Repeat this process for the other leg.
A quadriceps stretch is done in the following steps;
- Stand and rest your arms on a chair or wall for support
- Lift one foot backwards and grab your ankle.
- Bring the heel of that foot towards your buttocks and hold this position for about 30 seconds.
- This would pull the quadriceps femoris in front of the thigh.
- Ensure your knees are together and stop the stretch once you feel a strong pull in your thigh
- Repeat this process for the other leg
A hamstring stretch strengthens the hamstring muscles and is performed in the following steps;
- Sit on the floor and keep your back straight
- Keep your legs straightened out
- Place your hands on the floor with your palms touching it and slide them to touch your ankles
- You will feel a pull along the back of your thigh as your hand slides towards your ankles. Stop the stretch at this point and hold the position for about half a minute
- Repeat the process for the other knee
- Avoid locking your knees or arching your back in the process.
The non-steroidal anti-inflammatory drugs (NSAIDs) such as naproxen and ibuprofen relieve pain and swelling in the knee after an injury.
Oral or topical forms of these may be used together. In severe cases, opioid analgesics such as tramadol may be necessary to abate the pain and resolve knee stiffness.
In cases where the inflammation is not abated by analgesics, your doctor may inject corticosteroids routinely into the site of pain to relieve the inflammation.
Avoid Prolonged Postures
Your knee may stiffen as a result of maintaining a resting position for a long time. For example, after prolonged rest, it is recommended to make simple movements such as bending the knee back and forth gently for a few seconds to make the knee flexible before getting up.
It is also recommended that one takes occasional breaks of activity when the knee is in a prolonged resting state.
Some studies have shown that omega-3, chondroitin, and glucosamine relive symptoms of knee stiffness by strengthening the joint structures and lowering inflammation.
Although conservative treatment protocols are often effective at resolving knee stiffness, particularly if applied within 24 to 72 hours of onset of symptoms, there may be a few occasions where the injury or disease condition requires more advanced treatments such as osteotomy and surgical replacement of the knee joint in a process called arthroplasty.
Tips on How to Prevent a Stiff Knee
- Maintain a healthy weight: Obesity is a risk factor for so many types of knee arthritis. Obesity adds more stress to the knee and may even contribute to reduced activity which weakens the machinery of the knee.
- Low-Impact Exercises: These cannot be emphasized enough. Regular low impact exercises such as walking, bicycling, and swimming improves knee flexibility and strength preventing stiffness.
- Proper Footwear: It is advisable to wear footwear that provides good foot arch support. This stabilizes your pelvis and ensures proper alignment of the structures of the knee joint.
While conservative management such as PRICE, use of analgesics, physical therapy, and postural modifications may effectively reduce the symptoms of knee stiffness, the nature of injury or causative disease may necessitate advanced treatment such as surgery.
Essential tips for preventing knee stiffness include maintaining a healthy weight, wearing proper footwear, and building the muscles of the leg and thigh with stretch exercises.