Unresolved Osgood-Schlatter disease

Clinical History

A 28-year-old semiprofessional basketball player presented with anterior knee pain, mostly during sports activities.
The history included Osgood Schlatter disease at the age of sixteen, with a constant non debilitating pain at the insertion site of the patellar ligament.
Clinical examination revealed focal swelling and mild tenderness in the anterior proximal tibia.

Imaging Findings

MR imaging of the knee joint was performed with a standard protocol.
The sagittal PD-w MR image (Fig. 1), shows ossicle formation within the distal patellar tendon, following an old avulsion injury. The sagittal fat suppressed PD-w MR image (Fig. 2a), shows oedema within the bone marrow of the avulsed ossicle and reactive focal bone marrow oedema at the subcortical proximal tibia. A high signal intensity area in the anterior and lateral subarticular tibia (Fig. 2b) can be seen, in keeping with stress reaction.

Discussion

A. Osgood-Schlatter is a traction apophysitis of the tibial tuberosity, prevalent in young teenagers that participate in sports involving mainly jumping [1, 2]. Repetitive quadriceps contractions cause traction on the secondary ossification centre of the tibial tuberosity, leading to avulsion of the early ossification centre and the fibrocartilage of the distal tibial tuberosity physis [3].

B. Clinical symptoms include anterior knee pain exacerbated by sports activity. Clincal findings include local swelling and tenderness to palpation. Pain may be provoked with knee joint passive flexion or extension against resistance. Both knees may be involved in 20%-30% of cases [2, 3]. The diagnosis is usually clinical and the disease is self limited. Imaging is required in cases where conservative treatment fails and the symptoms persist. In addition, in adult high level athletes, imaging may disclose another coexistent pathology.

C. Lateral plain radiographs show fragmentation of the tibial tubercle and/or soft tissue swelling [1]. However, in early stages the findings may not be conclusive. In cases where radiographs show no abnormalities, MR imaging may show oedema in the tibial tubercle and around the patellar tendon insertion, as well as retropatellar bursitis [3]. In unresolved cases, MR imaging may show avulsed ossicles within the tendon as well as other causes of pain, such as stress reaction, which was observed herein [3]. Ultrasound shows ossification centre fragmentation, thickening of the patellar tendon insertion and infrapatellar oedema.

D. The disease typically resolves with skeletal maturity. It is conservatively treated with limitation to non-painful activities, icing and NSAID prescription. In the adult life, the patients may be free of symptoms, except perhaps for pain when kneeling and for complaints of a prominent tibial tubercle [1, 3]. The impact of imaging is important in treatment planning regarding persisting symptoms in adolescents or investigation of coexistent pathology in adult athletes. In unresolved cases, surgical removal of intratendinous ossicles is an option [3]. The procedure may be carried out arthroscopically, with excellent results [4, 5].
In our case treatment included local injections of analgesics, rest from training for 3 weeks (weight bearing protection for 1 week) and a 3 week rehabilitation programme focusing on the the extensor mechanism.
 The clinical outcome was very good with elimination of pain and a remaining anterior knee irritation without any downgrading of sports performance.

E. In athletes with unresolved Osgood Schlatter disease, MRI may disclose the coexistence of other injuries, such as a stress reaction.

Differential Diagnosis List

Final Diagnosis

Unresolved Osgood-Schlatter disease.

URL:	https://www.eurorad.org/case/12408
DOI:	10.1594/EURORAD/CASE.12408
ISSN:	1563-4086