Cartilage Lesions: What’s the Hype?

Courtesy: Grant Garcia MD, Seattle

Introduction

• A live educational program featured an expert orthopedic surgeon specializing in sports medicine and shoulder surgery.
• The speaker has extensive experience in sports medicine, surgical innovation, and orthopedic research, with more than 80 peer-reviewed publications.
• Professional activities include clinical practice, research collaboration with orthopedic companies, product development, regulatory testing, and surgical education.
• Experience also includes service as assistant team physician for professional sports teams in the United States.

Background of Cartilage Transplantation

• Cartilage injury refers to damage to articular cartilage within synovial joints.
• Common causes include trauma and degenerative joint conditions.
• Typical symptoms include:
  • Pain
  • Swelling
  • Restricted joint movement
  • Catching or locking sensation in the joint

Structure and Function of Articular Cartilage

• Articular cartilage is composed of chondrocytes embedded in an extracellular matrix.
• Its primary functions are:
  • Providing a smooth surface for joint movement
  • Acting as a shock absorber within the joint
• Cartilage has very limited capacity for self-repair, which makes treatment of cartilage injuries challenging.

Concept of Cartilage Transplantation

• Cartilage transplantation involves implanting cartilage tissue obtained from a donor into a damaged joint surface.
• The goal is to restore the articular surface and improve joint function.
• This procedure is most commonly considered in young and physically active patients.

Principles of Cartilage Preservation

• Successful cartilage preservation requires careful patient selection and patience.
• Cartilage procedures are technically demanding and have success rates of approximately 70–80%, which is lower than procedures such as ligament reconstruction.
• Many patients require combined procedures, rather than a single isolated surgery.

Associated Procedures Often Required

Cartilage restoration surgery may need to be combined with other procedures, including:

• Anterior cruciate ligament reconstruction or revision
• High tibial osteotomy
• Meniscus transplantation
• Tibial tubercle osteotomy
• Distal femoral osteotomy
• Medial patellofemoral ligament reconstruction
• Other alignment or stabilization procedures

Decision Making: Surgery Versus Biological Treatment

Several factors influence treatment planning:

• Patient age
• Physiological age compared with chronological age
• Level of symptoms
• Desired activity level
• Patient willingness to undergo a prolonged rehabilitation period
• Tolerance for potential complications or imperfect outcomes

Rehabilitation and recovery can take 1–2 years depending on the procedure.

Situations Where Treatment May Not Be Required

• Not every cartilage lesion requires surgical treatment.
• Some patients with cartilage defects may remain stable without intervention.
• In certain cases, cartilage lesions discovered during ligament surgery do not require additional treatment.

Evidence Regarding Microfracture

• Studies comparing microfracture with simple debridement in patients undergoing ligament surgery showed:
  • Patients treated with microfracture had worse functional and pain scores.
  • Debridement alone did not negatively affect outcomes.
• Therefore, routine microfracture for cartilage lesions is becoming less common.

Patient Selection for Cartilage Treatment

Treatment decisions should be based primarily on clinical symptoms rather than imaging findings.

Important symptoms include:

• Persistent swelling
• Joint pain
• Locking or catching sensations

Additional considerations:

• Secondary damage to the meniscus
• Early changes in surrounding bone or cartilage
• Risk of progression to osteoarthritis

Diagnostic Arthroscopy

• Many surgeons perform diagnostic arthroscopy before definitive cartilage restoration surgery.
• Benefits include:
  • Direct visualization of the defect
  • Identification of additional joint problems
  • Improved surgical planning
  • Better patient counseling regarding treatment options

Reasons for Performing Cartilage Repair

Evidence suggests that untreated cartilage defects may lead to:

• Worse clinical outcomes over time
• Increased progression of osteoarthritis

Cartilage repair may slow the progression of joint degeneration, even though it does not eliminate the risk entirely.

Treatment Algorithm for Cartilage Lesions

Management options vary depending on defect size and severity.

Common approaches include:

Minor lesions

• Debridement
• Chondroplasty

Small focal defects

• Autologous cartilage grafts
• Bio-cartilage techniques

Moderate defects

• Matrix-associated chondrocyte implantation

Large defects or those involving bone

• Osteochondral allograft transplantation
• Combined procedures with meniscus transplantation

Comprehensive Knee Evaluation

Successful cartilage restoration requires assessment of several factors:

• Patient history and physical examination
• Imaging findings
• Limb alignment
• Ligament stability
• Meniscus integrity

Ignoring any of these elements can lead to failure of cartilage surgery.

Common Challenges in Cartilage Surgery

Factors that make cartilage restoration difficult include:

• Limited training opportunities in high-volume centers
• Time-consuming evaluation and patient counseling
• Requirement for multiple staged procedures
• Complex postoperative rehabilitation

Patients with multiple previous knee surgeries often have less favorable outcomes.

Cartilage Graft Procurement

Key steps in obtaining cartilage grafts include:

• Tissue retrieval from donors within approximately 24 hours
• Sterile processing and laboratory testing
• Screening for infectious diseases
• Viability testing of cartilage cells

The graft is typically implanted within 28 days to maintain optimal chondrocyte viability.

Graft Matching

• Magnetic resonance imaging is commonly used to match donor cartilage to the recipient joint.
• Specialized software helps identify the most appropriate graft size and contour.
• Certain areas of the knee, such as the trochlea, are more difficult to match accurately.

Surgical Technique Overview

Typical steps in osteochondral graft implantation include:

• Preparing the defect by removing damaged cartilage
• Creating a cylindrical recipient socket in the bone
• Harvesting and shaping the donor cartilage plug
• Matching graft orientation carefully
• Press-fitting the graft into the prepared defect
• Ensuring the surface is flush with surrounding cartilage

Special Considerations for Patellofemoral Lesions

Patellofemoral cartilage defects may require additional procedures such as:

• Tibial tubercle osteotomy
• Realignment surgery
• Correction of patellar instability

These procedures help optimize the mechanical environment of the joint.

Outcomes of Cartilage Transplantation

Return to Athletic Activity

Studies have reported:

• Approximately 88% return to sport
• Around 79% return to previous level of activity
• Average return to sports around 9–10 months

Better outcomes are generally observed in:

• Younger patients
• Patients with shorter duration of symptoms

Long-Term Results

Research has demonstrated:

• Patient satisfaction rates exceeding 90%
• Graft survival rates around 91% at 5 years
• Approximately 89% survival at 10 years

These outcomes are considered favorable for patients with otherwise progressive cartilage damage.

Additional Surgeries

Patients undergoing cartilage transplantation may require further procedures over time due to:

• Graft complications
• Joint degeneration
• Associated ligament or alignment issues

For some individuals, cartilage restoration becomes part of long-term joint management.

Return to Competitive Sports

Studies in competitive athletes show:

• About 77% return to sport
• Some athletes stop competing due to career progression or fear of reinjury rather than surgical failure.
• Psychological readiness plays an important role in return to play.

Comparison of Cartilage Repair Techniques

Systematic reviews comparing different cartilage procedures show:

• Osteochondral autograft transplantation: approximately 93% return to sport
• Osteochondral allograft transplantation: about 88%
• Autologous chondrocyte implantation: about 82%
• Microfracture: around 58%

Because of lower success rates, microfracture is now used less frequently.

General Patient Characteristics

Large reviews of cartilage transplant procedures report:

• Average patient age around 37 years
• Common causes include:
  • Post-traumatic cartilage injury
  • Osteochondritis dissecans
  • Idiopathic cartilage degeneration