A 20 year old patient presented with right knee pain. MRI exam was performed and the findings are presented.
A 20 year old basketball player with history of recurrent anterior right knee pain was referred to the Imaging Diagnostic Center by his GP. The patient had no history of prior medical problems and clinical examination revealed focal tenderness to palpation of the inferior patella region. MRI was performed.
On T2 weighted image (Fig 1) the proximal portion of the patellar tendon was thickened with focal lesion of high signal intensity (Fig 2a,b). On PD fat saturated images (Fig 3) the posterior margin of tendon was poorly defined at level of thickening.
In this case, MR imaging demonstrated a marked thickening of proximal patellar tendon and a focus of abnormal signal intensity in and around it. These features are characteristic of chronic patellar tendinosis or jumper’s knee.
Jumper’s knee is a debilitating condition characterised by activity related pain and/or soreness at the patellar tendon insertion into the patella. The aetiology and pathogenesis are not clearly known and is considered to be the result of tendinous microteans of the patellan tendon fibers due to repetitive microtrauma that can lead to tendon degeneration. Basketball and volleyball players as well as runners and cyclists are the most frequently affected group of athletes; in general, activities that demand violent contraction of the quadriceps musculature and overuse of the knee extensor mechanism are the main cause of this condition.
Although other sites of involvement have been described, the infrapatellar region if the segment of the patellar tendon that is most frequently affected. Diagnosis of the condition is commonly based on clinical examination and symptoms include anterior knee pain, usually localized to the patellar insertion of the patellar tendon. Further imaging studies are required when the diagnosis remains unclear after a thorough history and physical examination, in the case of recalcitrant pain despite adequate conservative therapy, or for preoperative evaluation. In addition, imaging is used in exclusion of further pathological conditions such as patellofemoral anthrosis, chondromalacia, and infrapatellar plica syndrome which may be difficult to distinguish clinically from patellar tendinosis. Imaging procedures include musculoskeletal ultrasound, CT and MRI examinations. Although US is an operator-depended technique and CT ability to evaluate tendon conditions is limited, these methods are capable to demonstrate the tendon’s thickness.
MRI is the modality of choice for the examination of musculoskeletal components, including tendons. It provides information on anatomical definition of the musculoskeletal system giving an excellent soft tissue contrast. In addition the method is useful for evaluating other bony and ligamentous structures around the knee. On MRI the patellar tendon appears homogeneously low in signal intensity. On condition of jumper’s knee the tendon appears thickened with a focal lesion of higher signal intensity posterior to the proximal portion of the tendon. Typically the thickness of the patellar tendon decreases from its proximal to its distal extent, us in our case.
The majority of patients with jumper’s knee responds to conservative therapy and may be followed up clinically. Some patients may benefit from surgery and the role of the radiologist is critical in determining the exact position and the extent of the tendon changes.
Patellar tendinosis (jumper’s knee)
1. MRI shows marked thickening of the proximal patellar tendon in the right knee, with a localized increase in signal intensity posteriorly.
2. The patellar tendon thickness gradually tapers from the proximal to the distal end, which is consistent with normal anatomical characteristics; however, abnormal thickening and signal changes are observed in the proximal region.
3. There is no significant extensive effusion in the surrounding soft tissue, and no obvious signs of fracture or rupture of other ligament structures.
Based on the patient’s age (20-year-old male), activity-related anterior knee pain, and the imaging findings, the following diagnoses are considered:
Considering the patient’s youth, potential sports history (if applicable), clinical symptoms (pain primarily during jumping or running), and the imaging findings indicating marked thickening and localized high signal in the proximal patellar tendon, the most likely diagnosis is “Patellar Tendinitis (Jumper’s Knee)”, i.e., chronic patellar tendon pathology.
Based on the above diagnosis, treatment and rehabilitation can be divided into the following phases:
Once symptoms have subsided, gradually resume functional training. The following recommendations apply:
If conservative treatment is ineffective, and symptoms persist for a prolonged period severely affecting athletic function, surgical intervention may be considered. Surgery aims to remove diseased tendon tissue and promote repair and restoration of patellar tendon integrity.
Disclaimer:
This report is a reference analysis based on the existing imaging data and clinical information. It does not replace an in-person consultation or the professional opinion of a physician. If you have further questions or if your condition changes, it is recommended to seek prompt evaluation and treatment by an orthopedic or sports medicine specialist.
Patellar tendinosis (jumper’s knee)
