Knee Cartilage Restoration and Repair
There are currently five major options available for surgical knee restoration.
Microfracture consists of arthroscopically creating small holes in the knee joint articular surfaces where full-thickness cartilage defects exist. The purpose of the procedure is to allow pluripotential marrow cells to get into the joint to regenerate a new fibrocartilaginous coating. The procedure is short and performed on an outpatient basis. It is necessary to use crutches for ambulation for six to eight weeks after the procedure. Only 35 lbs. of weight may be borne on the affected extremity during this time. Our in house results show that at least 75% of patients are substantially improved.
2. High Tibial Osteotomy (HTO)
High tibial osteotomy consists of cutting the tibia and straightening it. This procedure usually necessitates an overnight hospital stay. Pins are inserted in the knee and an external fixation device is worn for 2-3 months. After this time the pins are removed. The idea is to shift weight away from the diseased medial compartment and onto the more normal lateral compartment. The decrease in pressure results in cartilage regeneration in and of itself in many patients. However, HTO is combined with microfracture in most cases to provide even greater cartilage regeneration. We are conducting a biomechanical study of this combined procedure at the world-renowned Gait Analysis Laboratory at Rush University Medical Center, which has shown promising results so far. The procedure is effective in most patients for a period of at least several years. In some patients benefits may last over ten years.
High tibial osteotomy is a good option for patients under 60 years of age. It becomes even more attractive for progressively younger patients because it “burns no bridges”; it can be converted to a knee replacement if it fails. High tibial osteotomy is more durable than a replacement and permits a wider range of work and recreational activities, without fear of damaging or wearing out a knee replacement.
3. Meniscal Allograft Transplantation (MAT)
For persons who have much or most of their meniscus removed, a new meniscus from a cadaver can be implanted to provide cushioning. There is no clinical rejection because the tissue is not living. Success rates are in the 85% range. Patients go home on the same day or after an overnight stay and are weight-bearing immediately. Full return to function occurs at six months. We believe that this procedure can help slow the progression of arthritis. It can be combined with other procedures as needed.
This is an excellent option for patients under age 60 whose knees fit the other criteria.
4. Autologous Chondrocyte Implantation (ACI)
The coating in joints that allows them to glide freely and painlessly is hyaline articular cartilage. When defects develop in it, bone is exposed and pain results. These holes can now be filled by taking a tiny biopsy from the knee of the patient’s own articular cartilage. It is flown to the Genzyme biosurgery lab in Boston and grown in tissue culture. It is then flown back and implanted in the knee under a biologic patch. The cells take root and grow. Patients must be touch-down weight bearing for six weeks and then partial weight bearing for six weeks. After this time they may walk normally. Complete healing takes nine to twelve months. The procedure is FDA approved, reimbursed by all major insurance carriers, and success rates are in the 85-90% range.
This is an excellent option for suitable patients. Excellent results have been achieved in patients as old as 55 and as young as 15.
5. Osteochondral Allograft Transplantation (OCA)
A fresh living donor composite allograft of bone and cartilage can be implanted into a defect in the knee. These grafts are usually used for defects that have both deficient bone and cartilage but can be used in cases where a cartilage defect alone exists. The donor cells live on in the recipient, there is no clinical rejection, no drugs need be taken and good results are reported at ten and even fifteen years after surgery.
Go to our OCA page to learn more .
See These Published Papers for Additional Information:
Magnetic Resonance Imaging Measurement of the Contralateral Normal Meniscus Is a More Accurate Method of Determining Meniscal Allograft Size Than Radiographic Measurement of the Recipient Tibial Plateau. Prodromos, et al, 2007.