Patellar chondromalacia is a condition commonly seen in adolescents or young adults, with a higher prevalence in females, though there is no significant gender difference among athletes. The cartilage surface of the patella becomes rough, softened, fibrotic, fragmented, and may even detach. The exact cause remains unclear, but it is definitely associated with overuse and chronic strain of the knee joint.

bubble_chart Pathological Changes

The lesion center is located on the medial surface and medial aspect of the patella (there is an independent small articular surface on the inner edge of the medial surface of the patella, separated from the medial surface by a linear ridge). In the initial stage [first stage], the lesion begins in the deep and middle layers of the cartilage, with the collagen bundles contracting in a fascicular pattern, but without invading the cartilage surface. Therefore, the surface appears normal, but palpation reveals a sensation of the cartilage being undermined. If the lesion progresses further and involves the cartilage surface, fragmentation and detachment occur.

bubble_chart Clinical Manifestations

Dull pain behind the patella and on the medial side of the knee is the most common symptom, which worsens after exertion or when going up and down stairs. Sometimes, there is effusion in the knee joint. If the patella is pressed medially against the patellar cartilage surface, tenderness may be present, and there is also a distinct tender point anterior to the medial femoral condyle. During knee flexion and extension, the examiner's hand may detect crepitus beneath the patella. The condition fluctuates in severity and can persist for many years. X-rays often show no abnormalities.

In the early stages of the lesion, knee joint activity should be reduced, and protection with bandages or lightweight braces is recommended. If symptoms persist for several months without relief and affect work or daily life, surgery should be considered. There are many surgical methods, all with significant failure rates. A common approach involves removing the affected cartilage down to the subchondral bone and drilling holes to improve blood supply. However, some advocate for flattening the prominent medial femoral condyle, medial displacement of the patellar tendon insertion, release of the lateral expansion of the quadriceps, and smoothing the prominent patellar articular surface.