Focal defect of the cartilage
Defect of the articular cartilage due to any inflammation, injury or trauma causing partial or full thickness cartilage defect in a well defined focal area.
For focal necrosis of the cartilage and the underlying bone see the section for focal osteochondral necrosis (OCD).
These changes in the articular cartilage usually develop as a result of a major trauma and may affect almost any joint in the body. The most frequently involved sites are the knee, the hip the ankle and the elbow.
We are not sure about the exact mechanism of the injury. Supposedly torsion along with intensive axial load play important role in the development of the defect which involves either the cartilage only (chondral defect) or both the cartilage and the underlying bone (osteochondral defetct).
Susceptibility
In certain contact sports (e.g. handball, soccer, etc.), and in the presence of any instability in the joint (e.g. torn cruciate ligament) one has fairly higher chance for focal chondral injury.
Complaints
The joint usually swells up following the index injury, and may take a quite long time before it goes down (weeks or even months), and occasionally reoccurs. Non steroidal anti inflammatory drugs usually have only limited effect on the pain. Normal function of the joint would not return. Patients often complaint of temporary locking of the joint.
Usual protocol for examination:
· Assessment of the axis of the extremities
· Checking stability, range of motion
· Assessing retro patellar sensitivity
· Measuring muscle strength of the limb
· Checking for any hypersensitivity
· Taking x-ray if appropriate
· Magnetic resonance imaging (MRI) offers the best diagnostic value and very helpful for follow up as well.
Options for treatment
Rest, ice, compression and elevation of the joint is the first step in the treatment. Nonsteroid anti-inflammatory drugs and dietary supplements are recommended. If severe effusion and loose body is present arthroscopic removal and treatment of the damage may be necessary. Arthroscopy is also useful for the assessment of the cartilage lesion as the extent of the affected area and its relation to other lesions (mirror or kissing lesions) is crucial in the decision for treatment option. Similar chondral defects in adolescent and adult patients have a lot worse expectation for spontaneous healing than the young ones. The usually applied cartilage repair methods would be (depending mostly on the size of the lesion): microfracture, mosaicplasty, cartilage cell implantation or large allograft implantation.
Rehabilitation: once the pain is tolerable and the swelling disappeared gradual return to the physical activity is advised. Supervision of a physiotherapist is favorable. If surgery is necessary the postoperative rehabilitation must be conducted by specialist physiotherapist to regain full function of the joint.
