Chondral knee injuries have different manifestations and presentation modes. The symptoms and treatments depend on the size thereof, the location, the functional demands, the presence of chondral loose bodies, the thickness of the lesion, the limb alignment, the evolution time and the accompanying lesions.
The classic treatment techniques like debridement, abrasion or microperforating allow for treating small to medium-sized injuries or lesions presenting little symptomology. However, restoration techniques, where an attempt is made to coat the defect with cartilaginous tissue, are used on advanced lesions. While the focus should be fully customized, the two techniques most frequently performed by Dr. Gelber differ depending on whether the injury is only of articular cartilage or, on the other hand, the injury also compromises the underlying bone layer (osteochondral injury).
Chondral injury
Chondral lesions involving the full thickness of the cartilage normally need to be treated with a replacement or regeneration technique. Numerous treatments based on growth factors or supplements that promise regeneration are currently advocated. However, it has never been shown that this is a reality and instead their use in these cases has little basis in scientific knowledge. A recently developed technique which has demonstrated very favorable results is to associate a refinement of the so-called microfracture (i.e. nanofractures) with a chitosan gel.
The microfracture procedure involves making small channels in the subchondral bone to allow progenitor cells from the bone marrow of the patient access to the area of injury. They later help generate fibrocartilage that fills the chondral defect. However these cells are normally diluted in the area to regenerate due to their lack of containment. A refinement of the microfracture, which generated 3mm diameter channels, has been developed. The new technique, called nanofractures, makes channels of only 1mm in diameter, thereby allowing for increased accuracy and efficiency. To prevent progenitor cells being diluted, the technique is combined with the in situ administration of a scaffold. Together, they generate a clot with a particularly suitable microenvironment for stem cells to grow in and regenerate the cartilage. While no technique has been shown so far to perfectly regenerate the complex structure of the original cartilage, this one has shown encouraging clinical and histological results. Finally, Dr. Gelber is the only surgeon in Catalonia who perform fresh cartilage transplantation, avoiding the need for a knee prosthesis surgery in young patients. You might see some of his surgical procedures in the video section.
Osteochondral injury
When injuries affect not only the entire thickness of the cartilage but also the underlying bone, a technique that only regenerates the cartilaginous layer will fail in its attempt to recover normal knee function. Again, treatment depends on the size and location of the injury. However, Dr. Gelber prefers the transfer of the patient’s own osteochondral cylinders (autologous), the technique known as mosaicplasty. In cases where the lesion is too large, it may be necessary to source a tissue bank for the graft. Currently Dr. Gelber is the only surgeon in Catalonia to perform transplantation of fresh cartilage from young donors. It is the only alternative for severe and large lesions of the articular cartilage that actually restores the complex cartilaginous tissue.
Osteochondritis dissecans
Osteochondritis dissecans of the knee (OCD) is a disease caused by a temporary reduction of blood supply to the knee bone. It occurs most frequently in adolescents and generates pain due to the detachment of a fragment of cartilage and its underlying bone. However, the fragment is often only partially detached and can give a false sense of normalcy in the arthroscopic examination.
OCD symptoms include pain, swelling, limited movement and occasional knee lock ups due to detached osteochondral fragments within the joint.
The treatment of OCD mainly depends on two factors:
- The stage of the injury: In degrees 1 or 2, wherein the lesion is still not detached, the ability to cure with conservative treatment is greater than if the fragment is already partially or completely separated from its original site.
- The skeletal maturity of patient: in postpubertal patients, where growth plates are in an advanced stage of closure, the capacity for spontaneous healing or with the aid of conservative treatment greatly diminishes.
The surgical treatment of OCD is done arthroscopically in most cases. The treatment options depend on the size and course of the disease:
- Resection of loose osteochondral fragments: performed all at once in very limited situations. It is usually performed in conjunction with other more complex techniques.
- Fixation: It is the ideal situation for arthroscopic treatment. It is performed when the lesion is partially or completely detached. In many situations, although the injury appears to be in place, the fragment shows to be unstable when it is touched and pushed with arthroscopic instrumentation. In these cases, the diseased bone beneath the previously separated cartilage is eliminated. The bony defect is then filled with very small amounts of bone removed from the same knee to finally close the defect with healthy cartilage and fix with 1 or 2 screws. These screws are removed at about 2 months after placement. Although immobilization is not necessary during this period, weightbearing is not allowed.
- Reconstruction of the injury: In advanced cases of OCD in which the detached osteochondral fragment is not viable or in chondral defects for other causes, it is necessary to use the patient’s own osteochondral cylinders (mosaicplasty) to fill the defect arthroscopically in the vast majority of cases.