ACL Reconstruction: Allograft vs. Autograft

ACL Reconstruction:  Allograft vs. Autograft

By Erik Bassett, DPT

Recently, we posted a blog titled “Everyday People Rehabbing Major Knee Injuries with AZOPT.”  In this two part series, we focused on the rehab following a major tear in the ligaments of the knee.  In this scenario, AZOPT patient Josh had a surgical procedure known as an auto graft to repair the tears.  Many people wrote us wondering what exactly an autograft procedure is. 

First, just to refresh the memory, the ACL (anterior cruciate ligament) and PCL (posterior cruciate ligament) are inside the knee joint connecting the femur (thigh bone) to the tibia (large bone of the lower leg). The ACL and PCL form an “X” inside the knee that stabilizes the knee against front-to-back and back-to-front forces.  ACL tears occur approximately 200,000 times each year in America, of which nearly half require reconstruction.

There are two types of reconstructive surgeries to repair an ACL - allograft and autograft.  An allograft is a tendon used from something other than the individual patient, usually a cadaver.  An autograft is tendon used from the individual, usually the hamstring or patellar tendon.   What is the difference between the two types of reconstructive options, and is one better or worse than the other?  There are positives and negatives to each type of reconstructive surgery.

This year, The American Journal of Sports Medicine performed a meta-analysis, the best form of research, reviewing many articles on the subject written between 1999 and 2012[1].  According to the study, patients who received an autograft scored higher on a scale that rates common complaints of the knee.  Further, they report positive outcomes on a subjective report and positive results with a single leg hop test.  Comparatively, patients receiving an allograft report a positive return to pre-injury activity level along with a positive subjective report.  They also report positive results with a pivot shift and decreased anterior knee pain.  However, patients with an allograft procedure had a 3-fold increase in re-rupture rates compared to autografts.    

In March of 2011 I experienced a major ACL tear that required reconstruction.  I chose to have an allograft performed mainly due to the shortened length of recovery time.  With an allograft, there is a decreased recovery time due to smaller amounts of cutting other structures like the patellar and hamstring tendons.  While the recovery time is less with an allograft, after 12 months of rehabilitation both types of grafts result in equal knee range of motion, strength, and activity level if proper rehabilitation occurs.  To this day I am able to perform each and every activity the same as before my ACL reconstruction.  Occasionally, I experience only minimal pain after activity and mild aches during cooler weather. 

Rehabilitation is key to any ACL reconstruction.  Physical therapy is performed after an ACL reconstruction to enable the knee to recover in a timely manner.  Initial treatment following ACL reconstruction includes increasing range of motion both in flexion and extension, mild strengthening of knee and hip musculature, pain and swelling reduction using modalities, and soft tissue mobilization to increase tissue extensibility.   Crutches and a locked knee brace are typically used for the first 3 or 4 weeks.  As rehabilitation progresses, an increased amount of strengthening occurs.  It is important to strengthen the surrounding muscles to help support the ACL graft.

If you have ruptured your ACL and require a reconstruction, speak with your physician.  Generally, they will refer you to a surgeon for a consultation.  The surgeon will speak to you regarding the option for an allograft or an autograft.  Now that you know the difference between the two you can impress the surgeon with your knowledge.  Choose which type would be most beneficial for you in the long run.  When the operation is complete, call AZOPT to begin the rehabilitation process.  Good luck and happy recovery!

[1] American Journal of Sports Medicine. 2013 Apr 12. Bone-Patellar Tendon-Bone Autograft Versus Allograft in Outcomes of Anterior Cruciate Ligament Reconstruction: A Meta-analysis of 5182 Patients. Kraeutler MJ, Bravman JT, McCarty EC.