By Dr. Tal David, Synergy Orthopedic Medical Specialists
Tearing your ACL can be a stressful experience. A patient with an ACL tear often has several decisions to make; Do I do surgery or not? When is the best time to do surgery? And what are my graft options?
I’d like to provide you with some preliminary information that can help you decide which graft may be your best choice. Hopefully this will provide you with some talking points which you can then review with your surgeon.
When an ACL tears, it typically cannot be repaired. An ACL graft is the tissue that we use to reconstruct the torn native ACL. This tissue must come from somewhere, and therefore a surgeon can discuss with you which graft option and graft source is most appropriate for you. Generally speaking, there are two sources for an ACL graft; an allograft is donor or cadaveric graft or tissue that comes from a tissue bank. An auto graft is tissue that comes from the patient’s own body. There are 3 common sources of autograph tissue; patellar tendon, hamstring tendon and quadriceps tendon. The quadriceps tendon is a relatively new graft option and long- term outcome data is unavailable at this time. Comparatively, we have 20+ year data with patellar tendon and hamstring autograph.
So, let’s compare the three most common graft options on which we have decades of outcome data. Patients undergoing ACL surgery typically have 4 common questions; When can I come off my crutches? When can I be expected to return to my activities of daily living? When will I be independent from a brace? When can I return to unrestricted sports?
This table shows you the basic timeline for each of the 3 most common graft options that we’ve discussed. When coming off crutches, patients typically take somewhere between 1 and 2 weeks. A patient with a patellar tendon autograph can take a little bit more time coming off crutches because the front of the knee is a little bit more sore as compared to the hamstring option or the allograft option. Most patients will stay on crutches for somewhere between 1 and 2 weeks primarily for comfort. Return to activities of daily living often occurs somewhere between 4 and 6 weeks depending on the graft option. Whereas the patellar tendon autograph may be able to return to normal living activities a little bit faster, the hamstring can sometimes take up to 6 weeks.
Being independent from your brace requires some in-growth or incorporation of the graft; that is the time it takes for your body to grow into the graft much like a tree root taking in the soil. Being independent from your brace will require some incorporation. Incorporation is how long it takes for your knee to grow into the graph that’s placed at the time of surgery. The faster this happens, the faster you can get out of your brace.
Incorporation occurs slightly faster with a patellar tendon autograft and therefore you can often be free of your brace somewhere between 2 and 3 months from surgery. Incorporation takes a little longer with the soft tissue graft like a hamstring, so often we recommend using the brace for the first 3-4 months following hamstring autograph reconstruction. Incorporation takes the longest amount of time with an allograft which is a cadaveric tissue because there are no living cells in that tissue. As a result, your knee has to grow into the tissue and this will often require using the brace to protect the knee for approximately 4 months.
Much like coming out of your brace, returning to unrestricted sports requires the incorporation and the maturity of the graft in terms of its in- growth. This occurs fastest with the patellar tendon and as a result most professional athletes who can risk losing one season but not more will undergo a patella tendon autograph, and can then be expected to return to unrestricted sports around 8 months.
Hamstring autograph incorporation takes approximately 10 months, and therefore we typically restrict patients from returning to their sports for that period of time. The longest incorporation takes place with an allograft, and therefore we typically do not recommend returning to your unrestricted sport until 1 year from the time of your surgery.
So what are the drawbacks of these graft options? Well, as you can imagine, when we have to take tissue from one place and transplant it to another, the donor tissue or the area where the tissue came from can be weak for a period of time and can have some issues.
Taking tissue from your patellar tendon can lead to anterior knee pain with kneeling or squatting or bending. This can occur for up to 18 months following surgery. When we harvest the portion of the hamstring tendon, we often see hamstring weakness for up to 6 months. And with an allograft certainly in young patients, we’ve seen higher re-rupture rates, and so allograft options are really not advised for people under the age of 20.
I hope this helps you understand your graft options a little better. Obviously, you should discuss these with your surgeon and together make a plan that best fits your needs.
I’m Dr. Tal David. Good luck with your surgery!