Osgood-Schlatter Disease 

In 1903, Robert Osgood (1873-1956), a US orthopedic surgeon, and Carl Schlatter (1864-1934), a Swiss surgeon, concurrently described the disease that now bears their names. Osgood-Schlatter disease (OSD) is one of the most common causes of knee pain in active adolescents.

OSD is a traction phenomenon resulting from repetitive quadriceps contraction through the patellar tendon at its insertion upon the skeletally immature tibial tubercle. This occurs in preadolescence during a time when the tibial tubercle is susceptible to strain. OSD should be distinguished from overuse of the patella-patellar tendon junction, which is referred to as Sinding-Larsen-Johansson syndrome (the adolescent equivalent of jumper's knee).^[1] (See the images below.)

OSD is a very common cause of knee pain in children aged 10-15 years. This condition can cause loss of time from athletics; however, it is rarely a cause of permanent impairment or disability. (See Etiology and Prognosis.)

Because of a lack of a precise definition, some practitioners may find differentiating OSD from avulsion fractures of the tibial tubercle to be difficult. If the patient cannot ambulate, an avulsion fractures of the tibial tubercle is more likely because OSD patients typically can ambulate, albeit with pain. (See Physical Examination and Differentials.)

The onset of OSD is usually gradual, with patients commonly complaining of pain in the tibial tubercle and/or patellar tendon region after repetitive activities. Typically, running or jumping activities that significantly stress the patellar tendon insertion upon the tibial tubercle aggravate the patient's symptoms. A sudden onset of pain with no antecedent symptoms in the region of the tibial tubercle should alert the clinician to assess for a possible tibial tubercle avulsion rather than OSD. (See History.)OSD is a self-limiting condition. In a study by Krause et al, 90% of patients treated with conservative care were relieved of all of their symptoms approximately 1 year after onset of symptoms.^[2] After skeletal maturity, patients may continue to have problems kneeling or may have tenderness over an unfused tibial tubercle ossicle or a bursa that may require resection.^[3] Minimal association seems to exist between residual anterior knee painafterOSDandpatellarstability, as was notedintheKrause study. The authors also noted no cases of recurvatum from premature closure of the proximal tibial physis. (See Prognosis.)

Development of Osgood-Schlatter disease

In girls younger than age 11 years and in boys younger than age 13 years, the tibial tubercle consists of cartilaginous tissue. The secondary ossification center, or apophysis, of the tibial tubercle develops when girls are aged 8-12 years and when boys are aged 9-13 years. (During this stage of skeletal development, the Osgood-Schlatter lesion may occur.) (See Etiology.)

By the end of the ensuing 2 stages of bony development (eg, epiphyseal and bony stages), the growth plates of the proximal tibia fuse in males and females (usually when aged 14-18 y), and the OSD usually subsides.

The most commonly accepted theory regarding the development of OSD is that repeated traction (traction apophysitis) on the anterior portion of the developing ossification center leads to multiple subacute fractures or tendinous inflammation, resulting in a benign, self-limited disturbance manifested as pain, swelling, and tenderness.

The most common long-term long-term ramifications of OSD are pain on kneeling as an adult and the cosmesis of a bony prominence on the anterior knee. Less common complications are the persistence of a painful ossicle requiring surgical excision and a displaced avulsion of a tibial tubercle.

The cause of Osgood-Schlatter disease (OSD) is unknown; however, theories suggest that this condition is a result of repeated knee extensor mechanism contraction that causes partial avulsions or microavulsions of the chondrofibro-osseous tibial tubercle. OSD usually occurs in persons involved in sports that require running and jumping.

During running, gymnastics, and other sports requiring repeated contractions of the quadriceps, an extra-articular osteochondral stress fracture or microavulsion occurs. The proximal area of the patellar tendon insertion separates, resulting in elevation of the tibial tubercle. During the reparative phase of this stress fracture, new bone is laid down in the avulsion space, which may result in a deviated and prominent tibial tubercle. When an individual with an injured tibial tubercle continues to participate in sports, more and more microavulsions develop, and the reparative process may result in a markedly pronounced prominence of the tubercle, with longer-term cosmetic and functional implications. A separated fragment may develop at the patellar tendon insertion and may lead to chronic, nonunion-type pain.

In a magnetic resonance imaging (MRI) study of 20 patients with OSD, the patellar tendon was noted to attach more proximally and in a broader area to the tibia in patients with OSD.^[4] Approximately 50% of patients with OSD relate a history of precipitating trauma.

Histologic studies support a traumatic etiology.

Risk factors

Risk factors for OSD include the following:

• Age between 8 and 15 years
• Male sex
• Rapid skeletal growth
• Repetitive jumping sports

Incidence

One study found that Osgood-Schlatter disease (OSD) affected approximately 21% of athletic adolescents surveyed, as compared with a frequency of 4.5% in age-matched nonathletic controls.^[5]

One Finnish study found that OSD affected 13% of athletes.

Sex predilection

OSD occurs more frequently in boys, with a male-to-female ratio of 3:1, probably because a greater number of boys participate in sports.

Age predilection

OSD usually is seen in the adolescent years, after a patient has undergone a rapid growth spurt the previous year.

Girls who are affected are typically aged 10-11 years but can range from age 8-12 years.

Boys who are affected are typically aged 13-14 years but can range from age 12-15 years.

The prognosis in Osgood-Schlatter disease (OSD) is excellent. OSD usually resolves by the time the patient is aged 18 years, when the tibial tubercle apophysis ossifies. In approximately 10% of patients, however, the symptoms continue unabated into adulthood despite all conservative measures.^[6] This may be from residual enlargement of the tuberosity or from ossicle formation in the patellar tendon.

The likelihood for long-term sequelae increases in severe cases, in cases in which treatment is not sought, or in cases in which the patient demonstrates poor compliance with the physician's recommendations.

In the study by Krause et al, 90% of patients treated with conservative care were relieved of all of their symptoms approximately 1 year following symptom onset.^[2]

In some cases, however, discomfort may persist for 2-3 years until the tibial growth plate closes.

Inform patients about activities that aggravate Osgood-Schlatter disease and about the self-limiting nature of the condition. For patient education information, see the Foot, Ankle, Knee, and Hip Center, the Arthritis Center, and the Osteoporosis and Bone Health Center, as well as Knee Pain.