What are Chondral Injuries?
Chondral knee injuries refer to damage to the articular cartilage that covers the ends of the bones within the knee joint. This smooth cartilage surface allows the knee to move freely and absorb forces during walking, running, and sporting activities. Cartilage injuries can range from small areas of softening or surface damage to larger defects where cartilage becomes partially or completely detached from the underlying bone. Because cartilage has a limited ability to heal on its own, untreated chondral injuries can lead to ongoing pain, swelling, mechanical symptoms, and potentially the development of early osteoarthritis.
Causes
Chondral injuries may occur following an acute traumatic event or develop gradually over time due to repetitive loading and degeneration. Common causes include twisting injuries, sporting trauma, patellar dislocations, ligament injuries such as ACL tears, or direct impact to the knee. In some cases, cartilage damage develops as a result of chronic wear and tear, joint malalignment, instability, or previous injury. High-impact sports and activities involving pivoting, jumping, or sudden changes in direction can increase the risk of cartilage injury.
Symptoms
Patients with chondral knee injuries commonly experience :
- Pain : during weight-bearing activities, when squatting, when using stairs, during sport or physical activity.
- Swelling : that worsens after activity.
- Stiffness
- Mechanical : catching, locking and grinding sensations inthe knee
- Ongoing pain (in larger cartilage defects)
- Unstable : feeling in the knee (in larger cartilage defects)
- Difficulty returning to normal activity levels (in larger cartilage defects)
Diagnosis
Diagnosis begins with a detailed history and clinical examination of the knee. Your surgeon will assess swelling, joint line tenderness, range of motion, ligament stability, and the presence of mechanical symptoms such as locking or catching. Because cartilage injuries may occur alongside other knee injuries, careful assessment is required to identify associated ligament, meniscal, or patello-femoral problems. In some cases, chondral injuries are difficult to detect on examination alone and require imaging studies or arthroscopy for confirmation.
Imaging
Imaging studies are important in assessing the extent and location of cartilage damage. Standard X-rays may be performed initially to evaluate overall joint alignment, bone structure, and signs of arthritis, although cartilage itself is not visible on plain X-rays. MRI scans are the most useful imaging modality for assessing chondral injuries, as they can demonstrate cartilage defects, swelling within the bone, loose fragments, and associated injuries to ligaments or menisci. In certain cases, CT scans or diagnostic arthroscopy may also be used to further assess the joint and guide treatment planning.
Treatment
Conservative (non-operative)
Conservative treatment may be appropriate for smaller or less symptomatic cartilage injuries. Non-operative management typically includes physiotherapy to improve strength, joint control, and flexibility, as well as activity modification to reduce excessive joint loading. Anti-inflammatory medications, weight management, bracing, and injection therapies may also help relieve symptoms. Rehabilitation aims to reduce pain, improve knee function, and protect the remaining cartilage from further damage. Some patients are able to return to normal daily activities and lower-impact exercise without surgery.
Surgical Treatment
Surgical treatment may be recommended for patients with larger cartilage defects, ongoing pain, mechanical symptoms, or failure of conservative management. The type of surgery depends on the size, location, and severity of the injury, as well as the patient’s age and activity level. Procedures may include arthroscopic removal of loose cartilage fragments, cartilage repair techniques, microfracture surgery, cartilage grafting, or cartilage transplantation procedures designed to restore the joint surface. In some cases, associated problems such as ligament instability, malalignment, or meniscal injury may also need to be addressed to improve outcomes. Rehabilitation following cartilage surgery is often prolonged and carefully structured to allow healing while gradually restoring strength.
Recovery
Recovery after arthroscopic removal of loose cartilage fragments is usually quick, with early weight-bearing, a short rehabilitation period, and return to normal activities within a few weeks. In contrast, cartilage repair procedures such as microfracture surgery require a longer recovery, including restricted weight-bearing for several weeks and gradual rehabilitation, with return to sport typically taking 4 to 6 months. More complex treatments like cartilage grafting or transplantation involve the longest recovery, often requiring 9 to 18 months for full return to high-level activity. Across all procedures, physiotherapy is essential to restore strength, movement, and knee function