Knee Flexion Contracture - Causes, and Exercises

Discovers the knee flexion contracture deformity and its causes, physiotherapy treatment, and exercises for improving the range of knee flexion and extension. Knee flexion is a critical movement of the knee joint that allows knee bending, bringing the lower leg closer to the upper leg. This motion is essential for activities such as walking, running, sitting, and various athletic activities. Maintaining proper knee flexion range of motion (ROM) is crucial for normal joint function and overall mobility.

Biomechanics of Knee Flexion

The biomechanics of knee flexion involve the complex interaction of various structures within the knee joint, including:

1. Articular Surfaces: The knee joint primarily comprises the femur (thigh bone) and the tibia (shin bone). These bones articulate at the knee, with the patella (kneecap) gliding over the front of the joint.

2. Muscles: Several muscles play a significant role in knee flexion. The primary muscles responsible for knee flexion are the hamstrings, which include the biceps femoris, semitendinosus, and semimembranosus. These muscles contract to bend the knee.

3. Ligaments: Ligaments like the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) provide stability to the knee during flexion and extension movements.

4. Menisci: The medial and lateral menisci are cartilage structures that act as shock absorbers and facilitate smooth knee movement during flexion.

5. Bursae and Synovial Fluid: These structures reduce friction and aid in lubricating the knee joint during movement.

Causes of Knee Flexion Contracture

Knee flexion contracture refers to a condition where the knee joint becomes restricted in its ability to fully extend (straighten) due to various factors. Some common causes of knee flexion contracture include:

1. Muscle Imbalance: Weakness or tightness in the muscles surrounding the knee joint, particularly the hamstrings, quadriceps, or calf muscles, can lead to an imbalance, preventing full knee extension.

2. Post-Surgical Complications: After knee surgeries, such as ACL reconstruction or total knee replacement, scar tissue formation or inadequate rehabilitation can result in contractures.

3. Neurological Conditions: Certain neurological disorders, like cerebral palsy or stroke, can affect muscle control and lead to contractures over time.

4. Joint Inflammation: Conditions like rheumatoid arthritis or osteoarthritis can cause inflammation in the knee joint, leading to contractures as the joint becomes stiff and less mobile.

5. Trauma and Injury: Severe injuries or fractures involving the knee can result in scar tissue formation or damage to joint structures, restricting motion.

6. Prolonged Immobilization: Extended periods of immobilization, such as prolonged bed rest, can cause muscles and connective tissues to stiffen, leading to contractures.

7. Congenital Factors: Some individuals may be born with structural abnormalities in the knee joint that predispose them to contractures.

Physiotherapy Treatment and Exercises for Knee Flexion Contracture

Physiotherapy plays a crucial role in the treatment of knee flexion contracture. The goal of physiotherapy is to improve knee joint mobility, correct muscle imbalances, and enhance overall knee function. Below are some common physiotherapy treatments and exercises for knee flexion contracture:

1. Hamstring Stretch

• Sit on the edge of a chair or a bed.
• Extend one leg straight out in front of you.
• Bend your other knee, placing your foot flat on the floor.
• Gently lean forward from your hips, keeping your back straight.
• You should feel a stretch in the back of your thigh (hamstring).
• Hold for 20-30 seconds and repeat 3-5 times on each leg.

2. Quadriceps Strengthening

• Sit on a chair with your feet flat on the floor.
• Straighten your knee by lifting your heel off the ground.
• Hold for a few seconds, then lower your heel back down.
• Start with 2-3 sets of 10-15 repetitions and gradually increase.

3. Manual Therapy:

•  A physiotherapist may perform manual techniques, such as joint mobilizations and soft tissue massage, to reduce muscle tightness and improve joint mobility.

4. Continuous Passive Motion (CPM):

• CPM machines are used in a clinical setting to passively move the knee joint through a controlled range of motion. This can help prevent joint stiffness and promote healing after surgery.

5. Electrical Stimulation:

• Transcutaneous Electrical Nerve Stimulation (TENS) or neuromuscular electrical stimulation (NMES) may be used to relax muscles, reduce pain, and facilitate muscle activation.

6. Heat and Ice Therapy:

• Applying heat or ice can help reduce muscle spasms and inflammation, depending on the stage of rehabilitation.

7. Gait Training:

• Practicing walking with a normal gait pattern is essential to restore functional mobility and prevent further contractures.

8. Home Exercise Program:

• Your physiotherapist will design a personalized home exercise program tailored to your specific needs and progression.

9. Bracing:

• In some cases, a knee brace may be prescribed to maintain knee extension and prevent further contracture.

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6. Lateral Knee Pain Exercises & Treatment
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People also ask

What causes knee flexion contracture?

Knee flexion contracture can result from various factors, including muscle imbalances, joint inflammation (e.g., arthritis), prolonged immobilization (e.g., bed rest), trauma or injury, post-surgical complications (e.g., scar tissue formation), neurological conditions (e.g., stroke or cerebral palsy), congenital factors, and certain medical conditions. It involves a restriction in the ability to fully extend the knee joint, causing it to remain in a bent position.

How do you treat knee flexion contracture?

The treatment of knee flexion contracture typically involves a combination of conservative measures and, in some cases, surgical interventions: Physiotherapy: A structured physical therapy program includes stretching exercises to improve the range of motion and strengthening exercises to correct muscle imbalances. Stretching: Hamstring and quadriceps stretches help to gradually regain knee extension. Strengthening: Exercises targeting the quadriceps and hamstrings can restore muscle balance. Manual Therapy: Physiotherapists may use techniques like joint mobilization and soft tissue massage to improve joint mobility and reduce muscle tightness. Modalities: Heat, ice, or electrical stimulation may be used to manage pain and inflammation. Orthotics or Bracing: Depending on the severity, a knee brace may be prescribed to maintain knee extension. Continuous Passive Motion (CPM): In some cases, CPM machines are used in a clinical setting to gradually improve knee range of motion. Surgery: Severe contractures that do not respond to conservative treatment may require surgical release of tight tissues or joint procedures. Lifestyle Modifications: Patients may need to make modifications to their daily activities and posture to prevent contracture recurrence.

What muscle is involved in knee flexion contracture?

In knee flexion contracture, the primary muscle involved is the hamstring muscle group. The hamstrings consist of three muscles: the biceps femoris, semitendinosus, and semimembranosus. These muscles are responsible for flexing the knee, which means they bend the knee joint, bringing the lower leg closer to the upper leg. When these muscles become tight or imbalanced, they can lead to a knee flexion contracture, where the knee remains in a bent position and cannot fully extend or straighten. Addressing the flexibility and strength of the hamstrings is a key component of treating knee flexion contracture.