Will There Ever Be a “Real” Replacement for Knee Cartilage?

Orthopaedic & Spine Center
image of Dr. Boyd Haynes

Boyd W. Haynes III, MD

Often touted as the Holy Grail of Orthopaedic research, the search for an affordable and realistic knee cartilage replacement continues to this day.  Although many products on the market today claim to “replace” or “regenerate” cartilage, none has been proven to do what is promised.  In this article, we will examine the different options that claim to repair or replace cartilage and help you to separate the hype from the facts.

No product on the market today will replace or re-grow hyaline cartilage.  Period.  Anyone or anything that offers to do this is just selling you snake oil.  Medical technology has not advanced to the point that we can offer viable cartilage replacement to the general public.  Many drug and biomedical firms are fervently researching this problem, knowing that the company who discovers a true cartilage replacement will have laid the proverbial golden egg and their product will be sought-after by millions worldwide.

Human stem cells show the most potential for helping humans to regrow cartilage. Although there are many advances being made, the jury is still out on whether stem cells can grow new tissue when implanted on healthy, viable cartilage within the human knee joint.  Maybe we will see a breakthrough in the next ten years in which stem cell implantation will become a routine part of care for arthritis, but we aren’t there yet.

Are there products on the market that can help to ease the pain of bone-on-bone arthritis and help to “lubricate” the joint, making the lack of good cartilage more bearable?  Yes, there are some products that can offer some benefit and even surgical procedures that can help re-cover small areas of the joint.  One procedure, called Carticel, uses lab-grown cartilage, generated by autologous donation of cells.  This procedure is done mostly in young people and is indicated for a more focal loss of cartilage, versus a loss of a great amount of cartilage.  It is time consuming and quite expensive.

For older persons, the OATS (Osteo-articular Transfer System) procedure can be of help.  In this procedure, cartilage is transplanted from a healthy area of the patient’s knee to another less-healthy area that lacks an adequate covering of cartilage.  However, there are many drawbacks to this procedure, including its potential to permanently damage cartilage donor sites and its inability to cover large defects in the joint.

The surgeon could also perform the “Microfracture” technique to help regrow “Hyaline-like” cartilage, which is not as durable as the original hyaline cartilage.  As mentioned previously, we currently have no reproducible was to make hyaline cartilage.

There are many injectable joint “lubricants” on the market today and these offer temporary relief for persons with arthritis of the knee.  Some of the better-known brands are Hyalgen, Supartz and Synvisc.  These lubricants are administered in a series of three, four or five injections into the knee over a period of weeks.  The drawback to use of these injectables is that the medication cannot be administered at once but must be given in smaller doses which are spaced-out over time (one injection per week).   Many persons do not enjoy having multiple injections into their knee joint, so a single injection alternative is now available which unfortunately, doesn’t seem to have the same effectiveness as the series of injections.

Steroid injections into the knee joint are also used frequently to quiet inflammation and to relieve pain.   A disadvantage to having steroid injections is that they can only be administered several times a year and may cause more joint damage if administered too often.  These injections do not provide any “lubrication” effect, but only act to quell swelling and the inflammatory process inside the knee joint.