Introduction
Recent years have brought significant improvements in anterior cruciate
ligament (ACL) reconstruction, allowing surgeons to better address the
specific needs of each patient.
As I outlined in my last
column, decisions about how to approach an ACL injury depend on the patient's
age, size, and plans for continuing sports. These factors also affect
the choice of graft materials, whether to use platelet-rich plasma, and
the approach to rehabilitation, which are discussed here.
Choice of Autograft Graft Material
The choice of graft material presents a complex challenge. First, there's
the choice between autograft and allograft. Second, there's the choice
of tendons to be harvested for grafting. Each has some advantages and
potential disadvantages.
In autograft materials, the choices are patellar tendon, hamstring tendon
(the semitendinosus and gracilis muscles), or quadriceps tendon.
Autologous patellar tendon is extremely durable and has been used for the
past 30 years as the gold standard for ACL reconstruction in athletes.
The downside is that harvesting this tendon can cause anterior knee pain
and a higher incidence of osteoarthritis. I use it in my most competitive
athletes who put the greatest stress on the joint.
Using autologous hamstring tendon avoids anterior knee pain. And these
tendons are easier to harvest. On the downside, many athletes never quite
get back to full strength after this important tendon is harvested. And
the injury to the hamstring can cause an imbalance of strength in the
joint, increasing the risk for reinjury, especially in females.
Autologous quadriceps tendon has become more popular in the past 2-3 years
because it's a thicker tendon; you don't get anterior knee pain
from harvesting it, and it doesn't seem to have to the failure rate
associated with hamstring tendon. It's also fairly easy to harvest.
So it has many of the advantages without the disadvantages.
The obvious advantage of allografts is that they come from cadavers, so
harvesting the graft doesn't injure the donor. Allografts may come
from a patellar tendon, hamstring tendon, quadriceps tendon, or tendons
of the foot. Historically, allografts used in ACL reconstruction have
failed at a higher rate than autografts. The biggest factor has been radiation
for sterilization, which weakens the graft. Washes, detergents, and vacuum
techniques can effectively sterilize the graft without compromising its strength.[1,2]
Considerations for Allograft Material
My choice of allograft graft material varies from one patient to another.
First, because I want to match the width of the donor graft to the anatomy
of the patient, I look for age matches, when possible.
In younger athletes, a key question is whether the growth plates are wide
open. If they are within an inch of cessation of growth, we can treat
the athletes as adults. But in youngsters who have wide-open growth plates,
we want to stay away from those plates. We can tunnel above or below the
growth plates. Or we can do an iliotibial band procedure where we don't
make tunnels through the bones at all.[3,4]
Then I consider the patient and the sport. For example, a 275-lb offensive
lineman needs the biggest tissue patellar tendon or quadriceps tendon
I can get because of the pivoting force exerted on that knee.
On the other hand, a high school athlete who is a hurdler or sprinter needs
to use the muscles around the joint to optimal effect, so I don't
want to take any of the patient's own tissues. For this athlete, I
might consider an allograft.
For a 50-year-old skier, I would probably also use an allograft. Once a
patient gets above 30 years of age, I figure I'll pay a big price
in stiffness and soreness for any tissue I harvest from the patient. It's
like robbing Peter to pay Paul.
By contrast, in a 13-year-old gymnast, whose growth plates are open, I
wouldn't want to use a graft that has bone on either side. This would
create a bar at the growth plate, stopping the growth. So I might use
hamstring autograft, which is just soft tissue, or a similar soft tissue
allograft.
In short, in situations where there is more concern about the graft failing,
I might use an autograft, but in situations where there is more concern
about pain and stiffness, I might go with an allograft. However, because
other factors—such as a patient's age and sport—come into
play as well, every case is different. As a result, the surgeon's
strategy will vary from one patient to another.
Use of Platelet-Rich Plasma
The next consideration is the use of biologics—specifically, platelet-rich
plasma. The graft is dead when it goes in. It has to ligamentize and regenerate
to provide the support the joint will need. Stem cells gradually inhabit
the tissue, regenerating collagen, blood vessels, and other components
of a living tendon. In essence, the graft is a scaffold. Preliminary clinical
trials have suggested that applying platelet-rich plasma during the reconstructive
surgery can enhance this regeneration.[5]
If I had my druthers, I would use platelet-rich plasma in every ACL reconstruction
because I believe it offers significant advantages. But few if any health
plans cover its use, so I currently only use it in the most challenging
situations.
In the future, we may be able to do even better. Martha Murray, MD, an
orthopedic surgeon at Children's Hospital of Boston, has successfully
repaired ACL injuries in animals using a collagen matrix to attach the
ends of the torn ACL rather than removing the torn ACL and replacing it
with a graft. Her research suggests that this approach results in an equally
strong joint with less risk for osteoarthritis.[6] I'm looking forward to the results of clinical trials for such biologic
augmentation opportunities.
The Complex Process of Rehabilitation
The time it takes an athlete to go from the operating room to fully returning
to his or her sport depends on the surgeon's readiness to check off
a list of improved functions.
Early on, I look at simple measures of strength and range of motion. But
when the patient gets between 4 and 6 months from the procedure, my concern
is about regaining his or her functions on the field or court. For example,
basketball players have to dribble the ball and run in four directions—forward,
to both sides, and backward.
At 90 days, basketball players must do the box drill. They have to go to
the side of the court and jog down. When they get to the back of the court,
they jog to the left, and when they hit the other side of the court, they
go backward, then side-shuttle right. They then repeat the process in
the other direction. We also have them do layups from both sides.
For soccer players, we set up cones at 10 and 40 yards, and for 20 minutes,
they run in a box shape similar to that of basketball players. Each time
they run this drill, we ask them to do it a little bit faster.
At the fifth and sixth month after ACL surgery, we start adding other soccer
players back into the patient's recuperative training so that the
patient can do some noncontact practice with them. Then, as the patient
continues to improve, he or she can begin practice against opposing players.
We use similar routines for athletes in other sports.
Just about every athlete who undergoes ACL surgery is able to run within
90 days. The severity of the injury does not seem to correlate with the
time to return to play.
Many variables affect the success of rehabilitation; among them, the patient's
motivation, the surgeon's knowledge and skill, surgical variables
during the procedure, the expertise of the physical therapist, the expertise
of the athletic trainer—and whether the patient even has the benefit
of a professional trainer.
Even though most athletes are able to play sports after an ACL injury,
not all will return to the same level of competition they reached before
their injury. Moreover, athletes with ACL injuries have at least a 10-fold
increased rate of reinjury to either knee.[7] Thus, we must identify biomechanical susceptibility, loss of control,
and weaknesses.
I always consider prevention of reinjury to be my highest priority. So
I include as part of the injured athlete's rehabilitation programs
such as, in the case of soccer players, Prevent Injury and Enhance Performance (PEP)[8] and Fédération Internationale de Football Association (FIFA) 11+.[9]
Athletes playing for those teams that can provide the best possible rehabilitation
treatment will have the highest return-to-play probability. For a high
school athlete in an impoverished school, the odds of returning to play
may be a lot lower because he or she probably won't have access to
a sports medicine specialist and a physical trainer.
In my practice, I try to mitigate these disadvantages by overseeing all
aspects of rehabilitation until the athlete has fully recovered and is
ready to go back to the field. But it's impossible for an individual
surgeon to overcome all of the disparities of our healthcare system. For
that reason, I think that we'll continue to see a lot of variability
in which athletes return to play for a long time to come.
References
1.Rappé M, Horodyski M, Meister K, Indelicato PA. Nonirradiated
versus irradiated Achilles allograft: in vivo failure comparison. Am J
Sports Med. 2007;35:1653-1658.
Abstract
2.Tejwani SG, Chen J, Funahashi TT, Love R, Maletis GB. Revision risk after
allograft anterior cruciate ligament reconstruction: association with
graft processing techniques, patient characteristics, and graft type.
Am J Sports Med. 2015;43:2696-2705.
3.Kocher MS, Garg S, Micheli LJ. Physeal sparing reconstruction of the
anterior cruciate ligament in skeletally immature prepubescent children
and adolescents. J Bone Joint Surg Am. 2005;87:2371-2379.
Abstract
4.Al-Hadithy N, Dodds AL, Akhtar KS, Gupte CM. Current concepts of the
management of anterior cruciate ligament injuries in children. Bone Joint
J. 2013;95-B:1562-1569.
5.Vogrin M, Rupreht M, Crnjac A, Dinevski D, Krajnc Z, Recnik G. The effect
of platelet-derived growth factors on knee stability after anterior cruciate
ligament reconstruction: a prospective randomized clinical study. Wien
Klin Wochenschr. 2010;122(Suppl 2):91-95.
Abstract
6.Vavken P, Murray MM. The potential for primary repair of the ACL. Sports
Med Arthrosc. 2011;19:44-49.
Abstract
7.Paterno MV. Incidence and predictors of second anterior cruciate ligament
injury after primary reconstruction and return to sport. J Athl Train.
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8.Santa Monica Sports Medicine Foundation. Pep Program. 2016.
http://smsmf.org/smsf-programs/pep-program Accessed January 14, 2016.
9.FIFA 11+. What is FIFA 11+? 2011.
http://f-marc.com/11plus/home/ Accessed January 14, 2016.
Medscape Orthopedics © 2016 WebMD, LLC
Any views expressed above are the author's own and do not necessarily
reflect the views of WebMD or Medscape.
Cite this article: Mandelbaum on Grafts, Biologics, and Rehab in ACL Repair.
Medscape. Jan 21, 2016.