osteochondral

Osteochondral is an anatomical and medical term derived from osteo- (bone) and chondral (cartilage). It generally refers to structures or pathologies that involve both articular cartilage and the underlying subchondral bone, particularly at joint surfaces where the cartilage meets bone.

Anatomy and function: The osteochondral unit comprises articular cartilage, the tidemark where calcified cartilage begins, and the subchondral bone beneath. This interface distributes load and provides a resilient surface for joint movement. Growth and remodeling of this unit are coordinated through endochondral ossification during development and lifelong mechanical loading.

Pathology: Osteochondral defects or lesions describe focal damage to both cartilage and adjacent subchondral bone. Causes include acute trauma, repetitive microtrauma, avascular necrosis, or developmental conditions such as osteochondritis dissecans. Clinically, patients often present with joint pain, swelling, and sometimes mechanical symptoms like catching or locking.

Diagnosis and imaging: Evaluation combines clinical examination with imaging. Magnetic resonance imaging (MRI) is the preferred modality for assessing cartilage integrity, bone involvement, and lesion stability; computed tomography (CT) offers detailed views of subchondral bone and fracture lines.

Treatment and prognosis: Management depends on defect size, location, patient age, and lesion stability. Nonoperative approaches include activity modification and physical therapy. Surgical options aim to restore the osteochondral unit and may include microfracture, osteochondral autograft transfer (OATS) or allograft transplantation, autologous chondrocyte implantation, fixation of loose fragments, or biological scaffolds. Prognosis varies; smaller lesions in younger patients often respond well to cartilage-sparing procedures, while larger defects may require grafting or advanced reconstruction. Ongoing research explores tissue engineering and regenerative strategies to recreate hyaline-like cartilage with durable, integrated bone.