Osgood–Schlatter disease

Knee of a male with Osgood–Schlatter disease

Osgood–Schlatter disease causes pain in the front lower part of the knee.[9] This is usually at the ligament-bone junction of the patellar ligament and the tibial tuberosity.[10] The tibial tuberosity is a slight elevation of bone on the anterior and proximal portion of the tibia. The patellar tendon attaches the anterior quadriceps muscles to the tibia via the knee cap.[11]

Intense knee pain is usually the presenting symptom that occurs during activities such as running, jumping, lifting things, squatting, and especially ascending or descending stairs and during kneeling.[12] The pain is worse with acute knee impact. The pain can be reproduced by extending the knee against resistance, stressing the quadriceps, or striking the knee. Pain is initially mild and intermittent. In the acute phase, the pain is severe and continuous in nature. Impact of the affected area can be very painful. Bilateral symptoms are observed in 20–30% of people.[13]

Risk factors include overuse, especially sports which involve running or jumping.[3] The underlying mechanism is repeated tension on the growth plate of the upper tibia.[3] It also occurs frequently in male pole vaulters aged 14–22.[14]

Diagnosis is made based on signs and symptoms.[15]

Types

Three types of avulsion fractures.

OSD may result in an avulsion fracture, with the tibial tuberosity separating from the tibia (usually remaining connected to a tendon or ligament). This injury is uncommon because there are mechanisms that prevent strong muscles from doing damage. The fracture on the tibial tuberosity can be a complete or incomplete break.

Type I: A small fragment is displaced proximally and does not require surgery.

Type II: The articular surface of the tibia remains intact and the fracture occurs at the junction where the secondary center of ossification and the proximal tibial epiphysis come together (may or may not require surgery).

Type III: Complete fracture (through articular surface) including high chance of meniscal damage. This type of fracture usually requires surgery.

Example of how to stretch the quadriceps muscle.[6]

One of the main ways to prevent OSD is to check the participant's flexibility in their quadriceps and hamstrings. Lack of flexibility in these muscles can be direct risk indicator for OSD. Muscles can shorten, which can cause pain but this is not permanent.[17] Stretches can help reduce shortening of the muscles. The main stretches for prevention of OSD focus on the hamstrings and quadriceps.[18]

Direct stretching of the quadriceps can be painful so the use of foam rolling for self myofascial release can help gently restore flexibility and range of movement[19][20]

The use of foam rolling for self myofascial release can help gently restore flexibility and range of movement[19][20]

Straight leg raises help strengthen the quadriceps without the need to bend the knee. The knee should be kept straight, legs should be lifted and lowered slowly, and reps should be held for three to five seconds.

Isometric exercises such as the isometric leg extension have been shown to strengthen the knee,[21] reduce pain and inhibition,[22] and help the tissue repair through Mechanotransduction.[23]

Treatment is generally conservative with rest, ice, and specific exercises being recommended.[24] Simple pain medication may be used such as acetaminophen (paracetamol), or NSAIDs such as ibuprofen.[25] Typically symptoms resolve as the growth plate closes.[24] Physiotherapy is generally recommended once the initial symptoms have improved to prevent recurrence.[24] Surgery may rarely be used in those who have stopped growing yet still have symptoms.[24]

The condition is usually self-limiting and is caused by stress on the patellar tendon that attaches the quadriceps muscle at the front of the thigh to the tibial tuberosity. Following an adolescent growth spurt, repeated stress from contraction of the quadriceps is transmitted through the patellar tendon to the immature tibial tuberosity. This can cause multiple subacute avulsion fractures along with inflammation of the tendon, leading to excess bone growth in the tuberosity and producing a visible lump which can be very painful, especially when hit. Activities such as kneeling may also irritate the tendon.[32]

The syndrome may develop without trauma or other apparent cause; however, some studies report up to 50% of patients relate a history of precipitating trauma. Several authors have tried to identify the actual underlying etiology and risk factors that predispose Osgood–Schlatter disease and postulated various theories. However, currently, it is widely accepted that Osgood–Schlatter disease is a traction apophysitis of the proximal tibial tubercle at the insertion of the patellar tendon caused by repetitive micro-trauma. In other words, Osgood–Schlatter disease is an overuse injury and closely related to the physical activity of the child. It was shown that children who actively participate in sports are affected more frequently as compared with non-participants. In a retrospective study of adolescents, old athletes actively participating in sports showed a frequency of 21% reporting the syndrome compared with only 4.5% of age-matched nonathletic controls.[33]

The symptoms usually resolve with treatment but may recur for 12–24 months before complete resolution at skeletal maturity, when the tibial epiphysis fuses. In some cases the symptoms do not resolve until the patient is fully grown. In approximately 10% of patients the symptoms continue unabated into adulthood, despite all conservative measures.[28]

Osgood–Schlatter disease generally occurs in boys and girls aged 9–16[35] coinciding with periods of growth spurts. It occurs more frequently in boys than in girls, with reports of a male-to-female ratio ranging from 3:1 to as high as 7:1. It has been suggested that difference is related to a greater participation by boys in sports and risk activities than by girls.[36]

Osgood Schlatter's disease resolves or becomes asymptomatic in the majority of cases. One study showed that 90% of reported patients had symptom resolution in 12–24 months. Because of this short symptomatic period with most patients, the number of people who become diagnosed is a fraction of the true number.[37]

For adolescents between the ages of 12–15, there is a disease prevalence of 9.8% with a greater 11.4% in males and 8.3% in females.[38][39][40] Osgood-Schlatter's disease presents bilaterally in a range of about 20%-30% of patients.[38][39]

It was found that the leading cause for the incidence of the disease was regular sport practicing and shortening of the rectus femoris muscle in adolescents that were in the pubertal phase.[41] For there is a 76% prevalence of patients with a shortened rectus femoris in those who have the Osgood-Schlatter's disease.[41] This risk ratio shows the anatomical relationship between the tibial tuberosity and the quadriceps muscle group, which connect through the patella and its ligamentous structures.

In a survey of patients with the diagnosis, 97% reported to have pain during palpation over the tibial tuberosity.[42] The high risk ratio with people with the disease and palpatory pain is likely the reason that the number one diagnosis method is with physical examination, rather than imaging as most bone pathologies are diagnosed.

Research suggests that Osgood-Schlatter's disease also increases the risk of tibial fractures.[43] It's possible that the rapid tuberosity bone development and other changes to the proximal aspect of the knee with those who have the disease is the culprit to the increased risk.

Because increased activity is a risk factor for developing Osgood-Schlatter's, there is also research that may suggest children and adolescents with ADHD are at higher risk.[44] Increased activity and stress on the tibial tuberosity would be greater in a more active population in the 9-16 age bracket, but this study was still not conclusive as to which aspect of ADHD was the cause of the higher incidence.