Articular Cartilage Injuries

How Articular Cartilage Works In The Knee

Articular cartilage is a smooth, low-friction surface that covers the ends of the femur, tibia, and the back of the patella. It allows the joint to move freely, share load efficiently, and absorb shock during walking, running, and pivoting.

Cartilage has:

• Very little direct blood supply
• Limited capacity to repair once damaged
• A key role in distributing pressure over a wider area

When knee cartilage is injured, the underlying bone can become exposed to higher forces. Over time, this may contribute to symptoms such as pain during weight-bearing activities and swelling after use.

How Articular Cartilage Injuries Happen

Cartilage injuries can develop after a single event or gradually over many years.

Acute Traumatic Injury

A sudden twist, awkward landing, or direct blow may lead to articular cartilage injuries, including a localised cartilage defect in the knee. These incidents often occur during sports or unexpected accidents. In some cases, a piece of cartilage may partially lift (a flap lesion) or break away (a loose body) within the joint.

Repetitive Load and Early Degenerative Change

Repeating high-load activities, particularly in the presence of subtle alignment differences or past injuries, may gradually wear down parts of the articular surface. This can contribute to early degenerative change in focused areas, even when the rest of the joint still appears relatively healthy.

Cartilage Injury Associated With Other Conditions

Articular cartilage damage often occurs together with:

• Meniscal tears
• Ligament injuries such as ACL tears
• Previous fractures that extend into the joint
• Patellar instability or recurrent dislocations

Understanding the broader pattern is important, as treating cartilage alone without addressing underlying mechanics may limit long-term benefit.

Common Sites and Patterns of Cartilage Damage

Cartilage injuries can vary in size, depth, and location. These factors influence symptoms and potential treatment options.

Focal Defects

A focal defect is a clearly defined area where cartilage has been damaged while surrounding tissue remains relatively normal. These may occur on:

• The weight-bearing surfaces of the femur or tibia
• The groove where the patella tracks
• The back of the patella itself

Chondral Flaps and Loose Bodies

Sometimes, cartilage partially lifts from the bone, forming a flap that can move with joint motion. In other situations, a piece of cartilage or cartilage-and-bone may detach completely and become a loose body within the joint. This can cause catching, locking, or sudden, sharp pain.

More Widespread Degenerative Change

Broader thinning or roughening of the cartilage surface across a compartment of the knee may signal developing osteoarthritis. In these situations, cartilage injury is part of a more global joint process rather than a single isolated defect.

Typical Symptoms Of Articular Cartilage Injuries

Symptoms vary depending on lesion size, depth, and location, as well as your activity level. While these features cannot confirm a diagnosis on their own, they provide important clues during assessment.

Knee cartilage symptoms related to articular cartilage injuries might include:

• Pain with load-bearing, especially stairs, hills, squats, or longer walks
• Swelling that recurs after activity
• A feeling of catching, locking, or something interfering with smooth movement
• Localised tenderness around the joint line or behind the kneecap
• Reduced confidence in the knee during sport or rapid changes of direction

Some people experience pain mainly with impact or twisting, while routine daily activities remain manageable. Others find that even simple tasks, such as getting up from a chair, can be uncomfortable when cartilage damage is more extensive.

How Articular Cartilage Injuries Are Assessed

Assessment focuses on understanding not just the cartilage defect, but also how the rest of the knee is functioning.

Clinical History And Examination

Your surgeon will ask about:

• How and when your symptoms began
• Any particular injury event
• Activities that worsen or relieve discomfort
• Past injuries, surgery, and medical history

Examination typically includes:

• Observing swelling, muscle bulk, and alignment
• Assessing the range of motion and patellar tracking
• Checking for tenderness in specific regions
• Evaluating ligament stability and meniscal signs

Imaging Investigations

Depending on your symptoms and examination findings, imaging may include:

• X-rays, to assess joint space, bone alignment, and any degenerative changes
• MRI, to visualise cartilage thickness, defects, bone bruising, menisci, and ligaments
• CT scans, in more complex cases or when planning certain procedures

These investigations help determine whether your cartilage injury is focal and potentially repairable, or part of a more widespread joint change that may require a different treatment approach.

Non-Surgical Management Of Cartilage Symptoms

Not all articular cartilage injuries require surgery. Non-surgical knee cartilage treatment may help manage symptoms and support joint function in people with articular cartilage injuries, particularly in smaller or less advanced lesions.

Options may include:

• Activity modification to reduce impact and twisting loads
• Physiotherapy to improve strength, neuromuscular control, and movement patterns
• Weight management, when appropriate, to reduce joint load
• Simple pain relief or anti-inflammatory medication as advised by your GP
• Bracing or taping strategies in selected cases to support alignment or patellar tracking

Injections, such as corticosteroids or viscosupplementation, may sometimes be considered to help manage pain in specific scenarios. Any injection therapy should be discussed with your treating doctor so that potential benefits and limitations are clear.

Non-surgical management often plays a role before and after any surgical intervention, and for some people, it remains the main form of ongoing care.

Surgical Options That May Be Considered

Knee cartilage surgery may be considered when symptoms persist despite non-surgical care, or if imaging confirms a structural problem that is unlikely to settle on its own, such as a significant cartilage flap or loose fragment. Any decision is individualised and depends on your cartilage pattern, age, activity requirements, and broader joint health. Possible procedures include:

Arthroscopic Assessment And Debridement

Arthroscopy is a minimally invasive technique that allows direct inspection of cartilage surfaces. In some cases, smoothing frayed edges or removing unstable fragments may help reduce catching and irritation.

Cartilage Repair Or Restoration Techniques

For selected focal defects, your surgeon may discuss:

• Microfracture, which aims to stimulate new repair tissue by creating small channels into the underlying bone
• Osteochondral graft techniques, which move or transplant cartilage-and-bone plugs to fill a focal defect
• Other cartilage restoration procedures, where available and appropriate

Each technique has specific indications, benefits, and limitations. Outcomes may vary depending on lesion size, location, patient factors, and adherence to rehabilitation.

Addressing Alignment Or Associated Issues

When cartilage damage is linked to altered load distribution or instability, additional procedures may be considered, such as:

• Realignment surgery (osteotomy) to shift the weight-bearing away from a damaged area
• Ligament reconstruction to improve joint stability
• Meniscal repair or preservation strategies

In more advanced or widespread cartilage loss that has progressed to significant arthritis, partial knee replacement or total knee replacement may be discussed. At participating hospitals, Dr Negus can offer robotic-assisted knee replacement using robotic systems such as Mako and VELYS.

These technologies aim to assist with implant positioning and soft-tissue balancing, as part of the overall surgical plan. In Dr Negus’s practice, there is no additional surgeon fee for robotic knee surgery at participating hospitals, although overall costs still vary depending on your hospital, insurer, and level of cover.

Rehabilitation, Recovery, And Longer-Term Outlook

Rehabilitation is a key component of managing articular cartilage injuries, whether you pursue non-surgical or surgical treatment.

A typical recovery pathway may involve:

• Gradual reduction of swelling and restoration of range of motion
• Progressive strengthening of quadriceps, hamstrings, gluteal, and calf muscles
• Balance and neuromuscular training to improve joint control
• Careful reintroduction of impact and twisting activities, when appropriate

Timeframes vary depending on the type of injury and any procedure performed. Your surgeon and physiotherapist can help set realistic expectations and milestones suited to your situation. Results may differ from person to person and will depend on multiple factors, including the size and location of the lesion, your general health, and how closely rehabilitation guidance is followed.

When To Seek Review For Cartilage-Related Knee Symptoms

It may be helpful to seek specialist review if you experience:

• Recurrent swelling or stiffness after activity
• Localised pain that persists despite rest and simple measures
• Catching, locking, or a sensation that something is interfering with smooth movement
• Ongoing discomfort with stairs, squats, or impact exercise
• Uncertainty about imaging findings or previous treatment advice

An orthopaedic knee surgeon in Sydney, such as Dr Jonathan Negus, can help clarify whether articular cartilage injury is contributing to your symptoms and discuss suitable management options.

Next Steps

Articular cartilage injuries can be complex to understand, especially when symptoms overlap with meniscal, ligament, or early arthritic changes. A careful assessment can help identify the structures involved and guide a treatment plan that balances symptom relief, joint preservation, and your activity goals.

If you are concerned about possible cartilage damage in your knee and would like to understand your options, you can arrange a consultation with Dr Jonathan Negus for an individual assessment and balanced discussion of non-surgical and surgical pathways.

This information is intended as a general guide and may not apply to every situation. Assessment and treatment recommendations vary depending on individual circumstances. Please speak with a qualified health professional for advice specific to your condition.