Cartilage is a tough, flexible connective tissue found throughout the body, notably in the joints, nose, and ears. This smooth, rubbery material serves as a shock absorber and provides a low-friction surface for bones to glide over each other. The simple answer to whether torn cartilage heals on its own is generally no; this tissue has a poor capacity for self-repair, often requiring medical intervention to restore joint function.
Why Cartilage Struggles to Repair Itself
The limited healing potential of cartilage lies in its unique biological structure. Articular cartilage is entirely avascular, meaning it contains no direct blood vessels. Blood vessels deliver healing components, such as inflammatory cells and growth factors, to an injury site.
Since cartilage lacks a blood supply, its cells, called chondrocytes, must receive nourishment and oxygen via diffusion from the surrounding synovial fluid. This slow diffusion process is adequate for maintenance but inadequate for mounting a rapid repair response after a significant injury. Cartilage is also aneural, lacking nerve endings, which can lead to delayed pain signaling. Furthermore, it is hypocellular, containing a sparse population of chondrocytes specialized for maintaining the existing matrix rather than rapidly synthesizing new tissue to fill a defect.
Distinguishing Types of Cartilage Tears
The potential for a torn piece of cartilage to heal depends on the specific tissue damaged and the location of the injury. Articular cartilage, the smooth hyaline cartilage on the ends of bones, has virtually no ability to heal if the tear is confined to the tissue itself. These partial-thickness tears do not reach the underlying bone, isolating the chondrocytes from any healing response.
Meniscal and labral cartilage, which is fibrocartilage found in structures like the knee meniscus, has a different prognosis determined by its blood supply. The meniscus is divided into zones based on its vascularity, known as the “Zone Concept.” Tears in the outer third, the “red zone,” have a rich blood supply and the greatest chance of healing, sometimes naturally or with surgical repair.
Conversely, tears in the inner third, or the “white zone,” have no blood supply and cannot heal spontaneously. A full-thickness tear that penetrates the subchondral bone will bleed, drawing in blood and mesenchymal stem cells from the bone marrow. This process forms a scar-like tissue called fibrocartilage, which is functionally inferior and less durable than the original hyaline cartilage.
Non-Surgical Management of Cartilage Injuries
For smaller, stable tears, conservative approaches focus on managing symptoms and stabilizing the joint. Initial care involves rest, ice, compression, and elevation (RICE), alongside physical therapy to strengthen surrounding muscles. Non-steroidal anti-inflammatory drugs (NSAIDs) are also used to mitigate pain and swelling. Injections are often used as an adjunct to provide symptomatic relief or promote a healing environment.
Types of Injections
Corticosteroid injections deliver potent anti-inflammatory medication directly into the joint space, offering rapid but typically short-lived pain relief. Hyaluronic acid injections, known as viscosupplementation, aim to restore the lubricating and shock-absorbing properties of the joint fluid, providing relief that can last for several months. Platelet-Rich Plasma (PRP) therapy involves injecting a concentration of the patient’s own platelets into the joint. These platelets release growth factors that stimulate tissue growth and modulate inflammation, though the long-term efficacy is still under study.
Surgical Options for Repair and Restoration
When conservative treatments fail or the tear is significant, surgical intervention is necessary to restore joint mechanics and prevent further damage. For meniscal tears in the vascularized “red zone,” meniscal repair involves stitching the torn pieces back together to preserve the tissue’s cushioning function. If the tear is in the avascular “white zone” or is too complex, a partial meniscectomy may be performed, removing only the unstable, damaged tissue.
For articular cartilage defects, a common initial procedure is microfracture, which exploits the body’s natural healing response. The surgeon creates small holes in the underlying subchondral bone, causing blood and bone marrow cells to leak into the defect area. This influx of cells forms a clot that eventually differentiates into fibrocartilage, a less durable repair tissue that fills the defect.
More advanced techniques aim to restore the native hyaline cartilage surface:
- The Osteochondral Autograft Transfer System (OATS), or mosaicplasty, is a single-stage procedure where plugs of healthy bone and hyaline cartilage are harvested from a non-weight-bearing area of the joint and transplanted into the damaged area.
- Cell-based procedures, such as Matrix-Induced Autologous Chondrocyte Implantation (MACI), are two-stage surgeries that involve harvesting a small sample of the patient’s healthy chondrocytes, culturing and multiplying them in a laboratory, and then implanting them onto a collagen membrane to fill the defect.