Jumper's knee / Patellar tendinitis
Jumper's knee, as its name implies, is knee sports disorder caused by overuse, often caused by jumping or landing in volleyball or basketball, or by repeated football kicking or dashing motions.
Cause and mechanism of onset
One of the factors is decreasing flexibility of the quadriceps muscle. In growing athletes, in particular, it is a chronic disorder that results when muscle growth fails to keep up with pace of bone growth, resulting in muscle stiffness that accumulates around the peripheral patella.
Frequent and prolonged flexion and extension of the knee joint with jumps or dashes can cause micro-damage to the patella periphery by repetitive over traction on the knee extension mechanism (pulling the quadriceps muscle add traction to patella, patellar tendon and tibial tuberosity). The condition can cause changes in the tendon parenchyma, such as bleeding, edema, mucoid degeneration (mucous degeneration of connective tissue), and fibrinoid degeneration (deposition of fibrinoid material in tissues, causing tissue damage and inflammation), resulting in minimal rupture and, rarely, complete rupture in the most severe cases.
Figure: Jumper’s Knee Mechanism
Repeated application of excessive traction to the knee-extension mechanism (pulling the quadriceps muscle into the patella, patellar tendon, and tibial tuberosity) causes micro-damage to the patella periphery
12-20 years old. It is particularly common among men in their teens.
There was no difference in the affected side between the left and right sides, but one-third of the players who complained of pain on the affected side had injury in both sides. Therefore, it is important to check the other side, even if the person feels pain on only one side.
35 of 108 patients reported pains at our medical check of the National Volleyball Team, for a rate of 32.4%.
There are pain and tenderness over the front of the knee during exercise (Photo 1), feeling heat and swelling. An important finding is that lying on the floor and bending the knee causes the buttocks to rise (Photo 2) to escape from tight pain on the front of the thigh.
The sites frequently affected are from the lower part of the patella to the insertion site of the patellar tendon (about 70%), from the upper part of the patella to the insertion site of the quadriceps muscle tendon (about 20%), and from the middle part of the patellar tendon to the attachment site of the tibial rough surface (about 10%).
Photo 1 Pain and tenderness, mainly from the patella to the insertion of the patellar tendon (anterior aspect of the knee)
Photo 2 Bending the knee of the patient with jumper’s knee, who is on one’s belly, rise a "buttock" to avoid pain.
It is a growth disorder of tibial tuberosity that occurs mainly in boys between the ages of 10 to 15.
Treatment and rehabilitation
Because the measurement of treatment depends on the degree of pain, the stage of the disease is divided into four stages. Recently, braces and supports are recommended for primary prevention and prevention of recurrence.
If pain occurs after exercise, thorough stress on the anterior thigh and icing on the affected area after exercises should be performed. It is recommended to apply supports. (Photo4)
If pain appears before and after exercise, in addition to the abovementioned, pause from jumping, exercise therapy of the lower extremities, centered on the knees and hip joint, and icing on the area are recommended.
In case of pain affecting movement, rest from exercise on a monthly basis and stretching to improve muscle balance in the lower extremities are performed, followed by resumption of training after pain relief.
Suturing is necessary in cases of rupture.
Photos 5 and 6 If you feel pain after the exercises, it is recommended to stretch the quadriceps muscle and iliopsoas. Please check for adequate stretching of the hip joint because both are less effective if the hip joint is not hyperextended.