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.
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