Tibial condyle fractures

Anatomy and biomechanical role

The medial and lateral menisci (meniscus medialis et lateralis) lie directly on the articular surface of the tibia. They are wedge-shaped fibrocartilage structures: up to 5 mm thick at the capsule, tapering gradually toward the center of the joint.

The main task of these structures is to adapt incongruent surfaces. The rounded femoral condyle rests on the flat tibial plateau, and the menisci significantly increase their contact area. According to the laws of physics, an increase in area leads to a decrease in pressure on the cartilage. Furthermore, being more elastic than hyaline cartilage, they act as effective shock absorbers.

Their stabilizing function (the "chock block" effect) is essential. The posterior horns of the menisci prevent displacement of the articular surfaces. Meanwhile, the medial meniscus is rigidly fixed to the tibia by deep fibers of the collateral ligament, making it less mobile and more prone to tears. The lateral meniscus, by contrast, has greater mobility and is separated from the capsule by the popliteus tendon.

Mechanisms of injury and classification

Injuries to the cartilaginous cushions of the joint are divided into acute traumatic and degenerative.

• Acute tears are typical for young individuals and athletes (especially in soccer or basketball). The classic mechanism is a sudden twisting of the lower leg with a flexed knee and a fixed foot.
• Degenerative tears occur in individuals over 40, are often asymptomatic, and require differentiation from osteoarthritis.

Depending on the direction of the tear line, several types are distinguished:

1. Radial — extending from the free edge to the periphery.
2. Horizontal (cleavage) — the line runs within the tissue, parallel to the tibial plateau.
3. Longitudinal — vertical tears running parallel to the capsule.
4. Bucket-handle tear — a variant of an extensive longitudinal injury where the detached central fragment displaces into the intercondylar notch while remaining attached to the anterior and posterior horns.

Clinical presentation and diagnostics

Cartilage tissue itself lacks pain receptors. Pain during injury arises from tension and irritation of the richly innervated capsule and synovial membrane.

Patients complain of localized tenderness strictly along the joint line (this is the most specific physical test). If the displaced fragment shifts, it can cause mechanical symptoms: clicking, a catching sensation, or even true joint locking (inability to fully extend the knee the last 20 degrees). Effusion is frequently observed.

MRI is recognized as the gold standard for imaging. A true tear on tomograms appears as a high-signal zone that definitively reaches the articular surface (femoral or tibial). If the signal alteration is confined within the cartilage, it indicates degeneration.

Important rule for ordering an MRI: the study is justified only if its result can alter the management strategy. For acute injuries in young patients, the threshold for ordering is low (it is crucial not to miss the window for repair). In elderly patients with suspected degeneration, MRI is rarely ordered, after first performing weight-bearing radiography to rule out osteoarthritis.

Principles of treatment

Strategy depends on the type of tear, blood supply zone, and symptom severity. Blood vessels are present only in the periphery (the "red zone"), so only injuries near the capsule have a chance of healing. The central "white zone" lacks regenerative potential.

• Conservative management: rest, NSAIDs, and physical therapy. Applicable for degenerative lesions or small, stable tears without locking.
• Emergency surgery: indicated for pronounced joint locking when a displaced fragment hinders movement.
• Arthroscopy: the priority method. Whenever possible, meniscus repair (suture) is performed. If the zone lacks blood supply, a partial resection (meniscectomy) is carried out. It has been historically proven (Fairbank changes) that complete meniscus removal leads to rapid development of arthrosis.
• Transplantation: allograft transplantation is used in young patients with a totally removed meniscus, before cartilage degeneration develops.

What else to study on this topic

• Assessment of ligamentous apparatus (ACL) integrity in trauma
• Specific clinical tests for joint line pathology
• Differential diagnosis with osteochondral lesions
• Weight-bearing radiography to rule out osteoarthritis
• Fairbank changes and long-term consequences of total meniscectomy

Other topics in the "Specialized Adult Traumatology" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.