Meaning
When the legs are straightened, the knees in this condition angle inward and touch one another. A frequent childhood condition known as knock knee occurs when the child is standing up but the lower leg splays out, causing a wider than-usual gap between the ankles. Adults can also get knocked knees, typically due to arthritis or a knee injury. Knock knee is prevalent in healthy children under the age of 6 to 7 years. The reasons for knocked knees are unknown in the majority of cases.
Causes
- Idiopathic: unknown cause.
- It occurs when a child’s weight falls to the outside of their knee joint, which is a normal part of their growth and development.
- Growth imbalance between the medial and lateral femoral condyles. The rapid growth of the medial condyles leads to knocking the knee.
- Rickets: a rare condition that affects a child’s bone development and is usually caused by vitamin D deficiency.
- Nutritional conditions: such as scurvy (vitamin C deficiency) which can adversely affect the development of bones and joints.
- Muscular or ligament weakness at the adolescent stage.
- Muscular paralysis of semitendinosus and semimembranosus.
- Fracture and injuries involving the knee joint.
- Secondary to flat foot, osteoarthritis of the knees, or spinal defects.
Symptoms
- If a child with a knock knee stands with their knees together, their lower legs will be spread out so that their feet and ankles are further apart than usual.
- The gap between their ankles is greater than 10 cm.
- There is a big difference between the angles of their lower legs when standing straight.
- There is an excessive inward or outward knee angle.
- They have knee pain due to the angle of their knee.
- They have difficulty walking or walking awkwardly.
- In severe cases of knock knee, poor posture may start to affect other parts of the body, such as the hip joints, back, or feet. This can cause pain, a limp, or a walking problem.
Diagnosis
- To assess the extent of the child’s knock knee, the distance between their ankles when their knees are together should be measured.
- To measure the distance between the ankles lay the child on their back and straighten out the lower limb. Place their knees together and measure the distance between the insides of their ankles.
- If the child is between 2 and 4 years old and has a gap between the ankles of 10 cm (4 inches) or less it will usually correct itself as the child grows.
- If the gap is greater than 10 cm, the child requires treatment. A gap of more than 10 cm in older children should be investigated to determine whether there is an underlying problem.
- An x-ray is to help identify any underlying problems that are causing the knee to knock.
- Other assessment includes- height, knee symmetry, gait pattern, and leg, hip, and foot alignment.
Exercises for knock knee
- Seated quadriceps contraction: Sit on the floor with one leg outstretched and a rolled-up towel under the knee. Contract the quadriceps and push the back of the knee into the towel. Hold in this position for about 3 seconds, relax, and repeat 10 times.
- Wall squats: Stand with your back to a wall and your heels far enough away so that when sliding down the wall to a squat position, your knees are in line with your toes. Feet should be shoulder-width apart to 90 degrees, but no lower. Keep stomach muscles slightly contracted while holding the squat 5 to 10 times.
- Straight leg raise: lie on your back on the floor with one leg straight out along the floor and the other knee bent with the foot flat on the floor. Tighten the thigh muscles in the straight leg and lift it about a foot off the floor. Hold for 5 seconds, then lower. Repeat for the other leg.
- Hamstring curls: holding onto the back of the chair, shifting weight to one leg, bending the other leg back, resting just on your toes on the floor. Tensed hamstring to lift heel toward buttocks. Hold the curled position for about 5 seconds, then lower the legs and repeat 10 times on each leg.
- Lunge: Stand up straight, take a big step forward, lift the back heel off the floor, and lower the body straight down, stopping when the front thigh is parallel to the ground. Slowly rise back up and repeat three sets of 10 repetitions on both legs.