Tuesday, October 25, 2016
ACL Reconstruction Graft Choice in Young Athletes
Anterior cruciate ligament (ACL) injuries currently require a reconstruction for active individuals desiring to return to activities that involve planting, cutting, turning, twisting or jumping. A reconstruction simply means a replacement of the ACL since repair currently does not work (see this link for exciting news regarding ACL repair). As part of the reconstruction a graft must be chosen and used. There are several options available, but young athletes and their families need to be careful in their graft decision process. Certain graft choices may not be the best for younger patients.
Broadly, there are two categories of graft: 1.) allograft (cadaver) and 2.) autograft (patient’s own tissue). There are advantages and disadvantages for both types. Allograft offers the advantage of no need to obtain a graft from the patient which may mean less pain and a quicker recovery. Unfortunately, the disadvantages include risk of disease transmission (HIV and Hepatitis 1/1,000,000), slower graft incorporation and a higher rerupture/failure rate. In an important study by the Multi-center Orthopaedic Outcomes Network (MOON) Group that we participated in at Washington University as an original MOON Group site cadaver grafts were noted to have a 4 times higher failure rate vs. autografts for patients of the same age and activity level. For example a 16 year old female high school team sport athlete has an ~5% ACL autograft failure rate in the first 2 years after surgery and ~20% failure rate over the same time period for an allograft. Read the study here: (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445196/) Obviously, that is a rate of failure unacceptable for young athletes. Conversely, in a patient over the age of 40 the failure rate remains 4 times higher, but at 2% vs. 0.5% the relative risk is very close and allograft may be a reasonable choice for an older adult patient.
This has been confirmed also in the revision (redo) ACL reconstruction setting with a 2.78 times higher failure rate for allografts noted by a study performed by the Washington University coordinated MARS Group. Read the study here: (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4447184/ )
There are 2 types of autografts commonly used: hamstring or patellar tendon. Both have advantages
and disadvantages. Hamstring grafts have a lower risk of kneeling pain, but less strong initial fixation and typically are ~1mm looser once healing is complete. Patellar tendon grafts have stronger initial fixation, heal a little tighter, but have a higher risk of kneeling pain. Data from Europe suggest the hamstring grafts may have a slightly higher (0.5—1.0%) risk of rupture, but this has not been duplicated in the US in similar studies. I typically recommend patients let their surgeons use the graft with which they are most comfortable. The small differences in the grafts typically do not matter clinically.