Differentials
Iliotibial band syndrome
SIGNS / SYMPTOMS
Lateral pain.
Tenderness on palpation of the iliotibial band 2 to 3 cm superior to the lateral joint line.
INVESTIGATIONS
Clinical differentiation usually suffices.
Plica syndrome
SIGNS / SYMPTOMS
Medial pain.
Tenderness and a palpable band along the medial edge of the patella.
INVESTIGATIONS
MRI with contrast or arthroscopy for definitive diagnosis.
Synovial plicae appear as bands of low signal intensity within the high-signal-intensity joint fluid.[51]
Patellar tendonitis/tendinopathy
SIGNS / SYMPTOMS
Inferior pain.
Tenderness of the inferior pole and patellar tendon.
INVESTIGATIONS
Clinical differentiation usually suffices.
Patellar fat pad inflammation
SIGNS / SYMPTOMS
Inferior pain.
Tenderness and swelling deep to the patellar tendon.
Pain is aggravated by knee extension.
INVESTIGATIONS
Clinical differentiation usually suffices.
Patellofemoral osteoarthritis
SIGNS / SYMPTOMS
Deep retropatellar pain.
Tenderness and swelling on undersurface of patella.
INVESTIGATIONS
Radiographic findings can show joint-space narrowing, subchondral sclerosis, and osteophyte formation, which are all consistent with osteoarthritis.
Quadriceps tendonitis/tendinopathy
SIGNS / SYMPTOMS
Superior pain.
Tenderness of the superior pole and quadriceps tendon.
INVESTIGATIONS
Clinical differentiation usually suffices.
Chondromalacia patellae/osteochondral defect
SIGNS / SYMPTOMS
Anterior pain.
In this condition there is softening of the patellar articular cartilage. It occurs in a subset of patients who present with anterior knee pain.
INVESTIGATIONS
MRI or arthroscopy is performed for definitive diagnosis.
Arthroscopic findings may show softening, blistering, fibrillation, or full-thickness ulceration of cartilage.
MRI may show decreased signal areas of patellar cartilage on T1-weighted sequences or osteochondral defect.
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