Cartilage Repair Knee Surgery
Restoring damaged cartilage in the knee to relieve pain and improve joint movement
Cartilage repair surgery, also known as articular cartilage restoration, is a procedure designed to restore the smooth surface of the knee joint when the cartilage has been damaged. The articular cartilage is the shiny white tissue that covers the ends of the bones where they meet in the knee. This cartilage plays a vital role in helping the joint move smoothly and pain-free. Damage to this cartilage can occur gradually through wear and tear or more suddenly due to injury. Over time, if left untreated, this damage can worsen and lead to a condition called osteoarthritis.
Cartilage repair surgery aims to encourage the growth of new cartilage tissue, reduce pain, and improve joint function. It is typically more successful in younger, active individuals with a single area of cartilage damage. Patients with more widespread joint wear may be better suited to other treatment options.
The type of cartilage repair surgery recommended will depend on several factors, including the size and location of the damaged area, your age, activity level, and overall joint health. The next section outlines the different surgical techniques available to restore cartilage in the knee.
MICROFRACTURE CARTILAGE REPAIR
A cartilage repair technique that stimulates new tissue growth in areas of joint damage
Microfracture is a technique that can be used to treat an articular cartilage injury or defect that exposes bone. This minimally invasive procedure encourages your body’s natural healing process to generate new cartilage, which can reduce pain and improve mobility. Microfracture is often recommended for patients with small, localised cartilage damage, such as those caused by injury or early-stage osteoarthritis. Unlike procedures that involve grafting or implanting new tissue, microfracture works by stimulating your body to create new cartilage within the damaged area.
Cleaning the Damaged Area
Dr Martin begins by gently clearing away any loose or damaged cartilage. This step, called debridement, prepares the surface for cartilage regeneration.Stimulating the Healing Response
Next, using a fine surgical instrument, Dr Martin creates a series of tiny holes, known as microfractures, in the bone just beneath the damaged cartilage. These small openings allow blood and bone marrow to enter the area.Formation of a Healing Clot
The released bone marrow contains stem cells and growth factors, which form a clot over the treated area. This clot serves as the foundation for new cartilage to develop.Development of New Cartilage
Over time, the clot matures into fibrocartilage. While this type of cartilage is not identical to the original (hyaline) cartilage, it can help cushion the joint and improve knee function.
Microfracture surgery may be a suitable option for patients with small, well-defined areas of cartilage damage. When performed at the right time, it can help improve knee symptoms and delay further joint degeneration.
Some of the key benefits may include:
Minimally invasive approach
Because the procedure is done arthroscopically, it requires only small incisions. This often means less pain after surgery and a shorter recovery time compared to more invasive techniques.Stimulates the body’s natural healing response
Microfracture encourages your own body to produce new cartilage using stem cells from the bone marrow. This makes it a straightforward treatment option for appropriate patients.May help delay more extensive surgery
By treating cartilage damage early, microfracture may reduce symptoms and slow the progression of osteoarthritis—potentially postponing the need for joint replacement.Improved movement and reduced pain
Many patients experience better knee function, with less pain and improved ability to perform everyday tasks.
While microfracture can be an effective treatment for small areas of cartilage damage, it’s important to understand its limitations. Not all patients are suitable candidates, and the results can vary depending on the size and location of the injury, as well as your age, activity level, and overall joint health.
Some of the limitations include:
Not suitable for large or widespread cartilage damage
Microfracture is most effective for smaller, isolated defects. It is generally not recommended for patients with advanced arthritis or multiple areas of damage within the knee joint.New cartilage is not identical to the original
The procedure promotes the growth of fibrocartilage, which is less durable and resilient than the original hyaline cartilage. Over time, this fibrocartilage may wear down more quickly, especially in active individuals.Results may diminish over time
While many patients experience initial improvement in symptoms, the long-term outcomes can vary. In some cases, pain or stiffness may gradually return, particularly with ongoing high-impact activity.Rehabilitation is essential and can be lengthy
A strict post-operative rehabilitation program is necessary to protect the new cartilage and support healing. This may involve using crutches for several weeks, limiting weight-bearing, and gradually increasing activity over time.
Dr Martin will discuss these factors with you in detail and help determine whether microfracture or another form of cartilage restoration is most appropriate based on your specific needs and long-term goals.
Recovery after microfracture surgery is a gradual process that plays a critical role in the long-term success of the procedure. Following surgery, Dr Sam Martin will provide a personalised rehabilitation plan tailored to your specific needs and the extent of your cartilage damage.
- Weight-bearing and crutches: You will likely need to use crutches for several weeks to avoid placing weight on the treated area while it heals. This helps protect the developing cartilage and gives it the best chance to grow properly.
- Physiotherapy: A structured physiotherapy program will begin shortly after surgery. Early rehabilitation focuses on restoring range of motion and preventing stiffness. As healing progresses, exercises are introduced to build strength and improve joint stability.
- Activity restrictions: High-impact activities such as running or jumping should be avoided for several months. Returning to sports or demanding physical work too early may disrupt the formation of new cartilage. Dr Martin will guide you on when it is safe to gradually resume more intensive activities.
- Follow-up care: Regular follow-up appointments will be scheduled to monitor your progress and make any necessary adjustments to your recovery plan.
While individual recovery times vary, most patients return to low-impact activities within 3 to 4 months, with full recovery taking up to 9 to 12 months. The success of microfracture surgery depends not only on the procedure itself but also on careful adherence to the rehabilitation plan.
KNEE CHONDROPLASTY
A keyhole procedure designed to smooth worn cartilage and relieve knee discomfort
Knee chondroplasty is a surgical procedure used to smooth damaged cartilage in the knee joint. It is often recommended when there is early cartilage wear or softening, but not enough damage to require more extensive surgery such as cartilage restoration or knee replacement. Dr Sam Martin may suggest chondroplasty if you’re experiencing knee pain, swelling, or mechanical symptoms such as clicking or catching that do not improve with non-surgical treatments.
Knee chondroplasty involves removing loose or damaged pieces of articular cartilage from the knee joint to reduce friction and irritation. The goal of the procedure is to create a smoother joint surface, which may help relieve pain, improve mobility, and slow the progression of further joint degeneration.
It is typically performed using a minimally invasive technique called arthroscopy, which allows Dr Martin to access and treat the inside of your knee through small incisions using specialised instruments and a small camera.
Dr Martin may recommend knee chondroplasty if:
You have mild to moderate cartilage damage (chondromalacia)
Conservative treatments such as physiotherapy, activity modification, or injections have not provided sufficient relief
You experience ongoing knee pain, swelling, or mechanical symptoms
You are not yet a candidate for more advanced procedures like cartilage grafting or joint replacement
Arthroscopic chondroplasty treatment is completed with arthroscopy, inserting thin surgical instruments in small incisions around your knee. The arthroscope sends the image to a television monitor. On the monitor, Dr Martin can see the structures of the knee in much greater detail. Once everything is ready to go, fluid is pumped in to expand the joint, which gives Dr Martin a clear view, as well as room to work. Dr Martin inserts small surgical tools to carefully remove damaged cartilage and any loose tissue. After the knee repair, excess fluid is drained, the instruments are removed, and the incisions are closed. As the knee heals, new “scar tissue” cartilage grows over the bare spot to replace the missing cartilage.
During the chondroplasty, Dr Martin trims and smooths roughened arthritic joint surfaces. He may find lesions on the cartilage that are atypical for the age of the patient. If this is the case, Dr Martin can take a cartilage sample from a non-contact surface during the arthroscopic knee surgery to save for up to seven years for a MACI procedure if needed.
Recovery after chondroplasty is generally quicker than more invasive knee surgeries, but it is still important to follow your post-operative plan closely. Most patients return to work and low-impact activities within 2–6 weeks, depending on the extent of the procedure and the physical demands of their lifestyle.
Key elements of recovery include:
Weight-bearing: You may be allowed to bear weight on the leg immediately or after a short period, depending on your case.
Physiotherapy: A personalised physiotherapy program will be prescribed to improve strength, flexibility, and function.
Pain management: Mild discomfort is common in the early stages and is usually well managed with oral pain relief.
Activity modification: High-impact sports and activities should be avoided for several weeks to allow the knee to heal.
Dr Martin will guide you through each stage of recovery and advise you on when it’s safe to return to your normal activities.
Knee chondroplasty may offer several benefits for selected patients:
Minimally invasive, low-risk procedure
Reduced knee pain and swelling
Improved joint function and mobility
Shorter recovery time compared to more complex surgeries
May delay or reduce the need for future joint replacement
While knee chondroplasty can improve symptoms, it does not regenerate cartilage or cure arthritis. The procedure is most effective for small or localised cartilage damage and may be less beneficial in advanced osteoarthritis.
In some cases, further treatment may be needed in the future if symptoms return or progress. Dr Martin will discuss your individual outlook based on your joint condition and lifestyle goals.
If you’re experiencing knee pain or have been diagnosed with cartilage damage, book a consultation with Dr Sam Martin to discuss whether knee chondroplasty may be suitable for you. He will provide a thorough assessment and personalised treatment plan to help you return to the activities you enjoy.
AUTOLOGOUS CHONDROCYTE IMPLANTATION (ACI)
Personalised cartilage regeneration for the knee
Autologous Chondrocyte Implantation (ACI) is an advanced surgical procedure designed to treat cartilage damage in the knee using your own cells. This two-stage treatment involves harvesting healthy cartilage cells (chondrocytes), growing them in a specialised lab, and then re-implanting them into the damaged area. ACI may be considered when cartilage damage is too extensive for simpler treatments like microfracture or chondroplasty but where joint replacement is not yet required.
Dr Martin offers ACI as part of his commitment to providing modern joint preservation techniques tailored to younger, active patients with localised cartilage defects.
Cartilage has limited ability to heal on its own. ACI is a regenerative technique that uses your body’s own cartilage cells to restore a smooth, functional joint surface. It is especially beneficial for patients with a single, well-defined area of damage in the knee, often caused by previous injury.
The procedure takes place in two stages:
Stage One – Cartilage cell collection:
Dr Martin uses keyhole (arthroscopic) surgery to remove a small sample of healthy cartilage from a non-weightbearing part of your knee. This sample is sent to a laboratory where the chondrocytes are isolated and grown over several weeks to increase their number.Stage Two – Cell implantation:
Once enough chondrocytes have grown, a second operation is performed to implant the cells into the area of damaged cartilage. The new cells are inserted beneath a membrane (or using a matrix, depending on the technique used) to keep them in place and encourage them to integrate with the surrounding tissue.
Over time, the implanted cells produce new cartilage-like tissue, helping to rebuild the joint surface and relieve symptoms.
ACI is typically recommended for:
Patients under 50 with a single cartilage defect (often from injury)
Areas of full-thickness cartilage loss (down to the bone)
Knee pain and swelling that has not responded to non-surgical treatment
Patients who wish to maintain an active lifestyle and avoid joint replacement for as long as possible
ACI is not usually suitable for people with widespread arthritis or multiple cartilage defects.
Recovery after ACI is longer than some other cartilage procedures, but careful rehabilitation is crucial to achieving the best results. Dr Martin and your physiotherapist will guide you through a structured rehabilitation program.
Key aspects of recovery include:
Hospital stay: Most patients stay in hospital for 1–2 nights following cell implantation.
Initial rest period: Limited weight-bearing for the first few weeks, often using crutches.
Physiotherapy: A gradual, tailored program focusing on range of motion, strength, and joint control begins soon after surgery.
Return to activity: Light daily activities may resume within 6–8 weeks, but full return to sport or high-impact exercise may take 9–12 months.
Adherence to your rehabilitation program is essential to protect the new cartilage and support long-term success.
For eligible patients, ACI may offer significant long-term advantages:
Uses your own cartilage cells to repair the knee
Aims to regenerate durable cartilage-like tissue
Can reduce knee pain and improve function
May delay or avoid the need for joint replacement
Helps preserve natural joint mechanics and mobility
While ACI is a promising technique, it may not be suitable for everyone. Potential limitations include:
Requires two surgeries and longer rehabilitation
Success depends on patient selection, rehabilitation, and cartilage quality
Best suited for isolated cartilage defects in otherwise healthy knees
Less effective for patients with advanced arthritis or multiple areas of damage
OSTEOCHONDRAL AUTOGRAFT TRANSPLANTATION (OATS)
A surgical technique that transplants healthy cartilage to repair localised knee joint problems
Osteochondral Autograft Transplantation, commonly known as OATS, is a surgical procedure used to repair focal cartilage injuries in the knee. This technique involves transplanting healthy cartilage and bone (a small cylindrical graft) from a non-weightbearing area of your own knee into the damaged area.
OATS is most often recommended for active patients with a single, well-defined area of damage, especially when the defect is too deep for procedures like microfracture or chondroplasty but not yet severe enough to require joint replacement. Dr Martin offers this technique as part of a range of joint-preserving treatments designed to relieve pain, restore function, and delay more invasive procedures.
The OATS procedure uses small plugs of healthy cartilage and underlying bone (called osteochondral grafts) taken from low-load areas of your knee joint. These plugs are carefully shaped and transplanted into the area of damaged cartilage, effectively “filling in” the defect with living, structurally sound tissue.
The goal of OATS is to:
Replace damaged cartilage and bone with healthy, load-bearing tissue
Restore the smooth surface of the joint
Improve knee stability, function, and reduce pain
The graft integrates over time and helps recreate the natural biomechanics of the knee, making OATS an excellent option for suitable younger or active patients.
Dr Martin may recommend OATS if:
You have a full-thickness cartilage defect (down to the bone) in one area of the knee
The affected area is small to medium in size (typically less than 2–3 cm)
You are under 50 years of age and physically active
You have persistent pain or mechanical symptoms (e.g. locking, catching) that haven’t improved with non-surgical treatment
OATS may not be appropriate for patients with widespread arthritis, multiple cartilage defects, or underlying inflammatory conditions.
OATS is typically performed under general anaesthesia and may be done arthroscopically or through a small open incision, depending on the location and size of the defect.
The procedure involves:
Harvesting the graft: Healthy cartilage and bone plugs are taken from a non-weightbearing area of the knee.
Preparing the defect site: The damaged cartilage is removed, and the site is prepared to accept the graft.
Transplantation: The graft(s) are precisely placed into the defect and press-fit into place, restoring the natural joint surface.
Dr Martin takes care to minimise disruption to other parts of the knee and ensure accurate alignment for optimal healing and function.
Recovery from OATS surgery involves a structured rehabilitation plan to promote healing and restore knee movement.
Typical recovery pathway:
Hospital stay: Usually 1–2 nights
Weight-bearing: Crutches may be required for 4–6 weeks, depending on graft location and size
Physiotherapy: Begins shortly after surgery to restore range of motion and strengthen the muscles around the knee
Return to activity: Low-impact activities may resume around 3 months; return to full sport or high-demand activities often occurs around 6–9 months
Dr Martin will monitor your recovery closely and adjust your rehabilitation plan as needed.
OATS offers a range of benefits for appropriately selected patients:
Restores healthy cartilage and bone using your own tissue
Can provide durable, long-lasting pain relief
Preserves knee structure and function
Reduces the risk of joint degeneration in the damaged area
Avoids the need for joint replacement in younger patients
Like all surgical procedures, OATS has its limitations:
Best suited for smaller cartilage defects in otherwise healthy joints
Requires harvesting tissue from another part of the knee, which may cause localised discomfort
Recovery time may be longer than with simpler procedures like chondroplasty
Success depends on surgical technique, rehabilitation, and patient-specific factors
Dr Martin will carefully assess your knee and discuss whether OATS or another treatment option is most suitable for your condition and lifestyle.
OSTEOCHONDRAL ALLOGRAFT TRANSPLANTATION (OCA)
Surgery designed to restore large cartilage defects
Osteochondral Allograft Transplantation (OCA) is an advanced surgical procedure designed to treat larger, more complex cartilage defects in the knee. This technique involves the transplantation of cartilage and underlying bone tissue from a deceased donor to replace damaged cartilage that lines the ends of bones in a joint. It is particularly useful for patients with large, focal cartilage defects, offering a durable solution to restore knee function and reduce pain.
While OCA is an effective method to repair cartilage injuries, it’s essential to understand the procedure’s complexities and the factors involved in its success. Dr Sam Martin works closely with patients to assess their suitability for osteochondral allograft transplantation, ensuring optimal outcomes for those with extensive cartilage damage.
Osteochondral allograft transplantation is a method of treating cartilage injuries that expose the underlying bone. In this procedure, a section of living tissue, which contains both cartilage and bone, is taken from a donor and shaped to precisely fit the defect in the patient’s knee joint. The transplanted tissue is referred to as an allograft.
The cartilage in the allograft remains viable and can integrate into the damaged joint if the tissue is “fresh” (i.e., not frozen or exposed to radiation). The procedure helps resurface damaged cartilage and restore the joint’s function, preventing further damage to the bone and reducing the risk of developing osteoarthritis.
Dr Martin may recommend osteochondral allograft transplantation for patients with the following conditions:
Large or complex cartilage lesions: Especially when the damage is larger than 1 cm or the defect involves both cartilage and underlying bone.
Osteonecrosis (bone death): Where the bone and cartilage are compromised, leading to potential joint collapse.
Failed previous treatments: Such as failed microfracture or autologous chondrocyte implantation (ACI).
Osteochondritis dissecans: A condition where a fragment of cartilage and bone becomes loose within the joint.
Joint reconstruction after a fracture: When cartilage and bone restoration is needed after traumatic injury.
Osteochondral allograft transplantation is often ideal for young, active individuals who have significant cartilage loss but have not yet developed widespread osteoarthritis.
This procedure is usually performed under general or spinal anaesthesia. An incision is made to expose the joint defect, and the following steps are taken:
Defect preparation: The damaged cartilage and underlying bone are removed, creating a stable bed for the graft.
Allograft preparation: A fresh osteochondral allograft is carefully selected from a tissue bank, sterilised, and tested for disease transmission. It is trimmed to match the size and shape of the prepared defect.
Graft insertion: The allograft is gently press-fit into the defect. Depending on the case, metallic screws and pins may be used to stabilise the graft.
Incision closure: The incision is closed, and a dressing is applied to the joint.
The success of the procedure depends heavily on the precision of the graft matching the defect and how well the graft integrates with the existing bone and cartilage.
After osteochondral allograft transplantation, patients will undergo a structured recovery process to promote healing and prevent complications:
Post-surgery bracing: A knee brace may be applied for the first 2 weeks to protect the graft site.
Weight-bearing restrictions: Crutches will be used to limit weight-bearing for 6–8 weeks.
Rehabilitation: Early movement is encouraged to restore range of motion. Physiotherapy will be gradually introduced over 8–12 weeks to strengthen the knee muscles and improve function.
Return to activity: Full return to activities may take 6–12 months, depending on the extent of the graft and the patient’s healing progress.
Dr Martin will guide you through every stage of your recovery to ensure the best possible outcomes.
OCA offers significant benefits for patients with large cartilage defects, including:
Restoration of both bone and cartilage: The allograft helps restore both the cartilage and the underlying bone, providing a comprehensive solution for joint damage.
Durable long-term results: Successful transplantation can provide long-lasting relief from pain and improved function, with some patients experiencing benefits for 10 years or more.
Prevention of arthritis progression: By replacing damaged cartilage, OCA helps delay the onset of osteoarthritis, potentially avoiding the need for knee replacement.
No need for a second donor site: Unlike autograft procedures, where tissue is taken from another part of your own body, OCA avoids creating additional defects.
While osteochondral allograft transplantation can be a highly effective procedure, it does have some limitations:
Risk of immune response: Although the allograft tissue is immune-privileged, there remains a small risk of immune-mediated rejection, particularly if the graft is not properly matched.
Availability of fresh grafts: Fresh allografts with the necessary cartilage thickness can sometimes be difficult to obtain, which may delay surgery.
Longer recovery time: The recovery process for osteochondral allograft transplantation is longer than that of simpler cartilage repair procedures, with a longer wait for full function.
Not a cure for arthritis: While the procedure can improve function and reduce pain, it is not a cure for generalized arthritis, and some patients may still require joint replacement in the future.
Osteochondral allograft transplantation can be a life-changing treatment for patients with significant cartilage damage in the knee.
So, if you have a large cartilage defect or have not responded to other treatments, contact Dr Martin’s clinic to discuss whether osteochondral allograft transplantation could help restore your knee function and alleviate pain.
