- Prevalence and cost of the
injury – over 250,000 in the US alone at average cost of $25,000 to
$50,000, this is a $5B health care cost annually
- Time on the disabled list –
due to the injury, surgery and rehabilitation, it is one of the injuries
that results in the largest amount of time on the DL for players
- Impact on future performance
– although percentage of players that return to play is debatable, the
percentage that return at the previous level of play is ~40%.
- Impact on future joint
health – studies show 79% have osteoarthritis in 12 years and 20% have
second ACL injury in 2 years.
When discussing ACL injuries, it is important to consider
the mechanism of injury. For our purposes,
we will classify these as:
- Contact ACL Injury – ACL injury
that results from contact with another player or object
- Non-contact ACL injury –
where there is no contact with another player. These account for the majority of ACL
injuries and are the ones targeted by most ACL Injury Prevention programs.
It is the non-contact ACL injuries that plague most
sports. Although we know what the
intrinsic and extrinsic factors are that lead to the primary non-contact ACL
injuries and have various programs developed to address, there has only been a
1.5% reduction in injury rates over the last 5 years. So developing a better understanding is
important to preventing. Knowing that
those who have had an ACL reconstruction (ACLR) are at risk for a 2nd
ACL injury, it is important to identifying factors which put them at risk for a
second injury so that this risk can also be minimized. Identifying the pre-injury and post-injury
risk factors will aid us in development of interventions and programs to better
address.
In the September issue of the American Journal of Sports Medicine, the authors of the study
entitled Risk Factors for Recurrent Anterior Cruciate Ligament Reconstruction: A
Population Study in Ontario, Canada, With 5 Year Follow Up, attempted
to identify some of those risk factors.
Methods: Using the Ontario Administrative Health Care
Database and the Registered Persons Database, the authors were able to identify
all primary elective ACLR procedures performed in Ontario from July 2003 to
March 2008. This included a total of
12,967 ACLR procedures with patients aged 15 to 60 years of age. Using these same databases, revisions and
contralateral ACLR were sought until January 2012. Comparisons were done for patient factors
(age, sex, comorbidity, etc), provider factors (surgeon volume, academic
hospital status, etc) and surgical factors (allograft vs. autographft, fixation
type, etc).
Results: For the 12,967 ACLR performed, these had a
mean follow-up of 5.2 years. For all the
subjects included in the study, the revision rate was 2.6% and the rate of the
primary contralateral ACLR was 4.6%.
ACLR performed at an academic hospital and the use of allograft
significantly increased the risk of revision of the ACLR. Younger age was the only patient factor that
increased risk for contralateral ACLR.
Discussion: The numbers reported in this study are much
lower than previous studies looking at ACL revisions or risk for 2nd
ACL injury. In an effort to determine
which is more relevant to our patients and our setting in the US, we must
consider all the factors. Considering
the design of the study, there may be several reasons for these lower reported
numbers.
- Health Care Delivery
System: This study was performed in
Ontario, Canada and hence could account for the variance in US published
studies vs. Canadian. So, does this
mean that ACLR procedures there have better long term outcomes than the US
or is it a result of the health care delivery model? In Canada, there is a substantial
waiting period between the onset of the injury and the actual surgery
itself (up to several months). This
waiting period may result in some choosing to opt out of having surgery,
which may impact. This is also
insurance driven data base.
Therefore, any athlete that chooses to self-pay for this surgery is
not included in this data.
- Age of Participants: This study also includes individuals up
to 60 years of age whereas most of the studies in the US use a much
younger population. In this study,
over 45% of the subjects were over the age of 30. Although you would think this would add
to more revisions, the opposite is true.
Since younger individuals are more likely to return to sport and more
aggressive sports, if ½ of your study population is not returning to sport
and at less risk then this would skew your data.
- Database driven
information: Since this is database
driven, there is no outcome information included so we have no idea what
the outcome is. Without this information,
we have no idea of what the activity level is with these patients post
ACLR. Were they able to return to
their prior level of activity or where they limited in their ability? Are those in the US more likely to have
revision due to the fact that they return to a higher level of
activity? This study also only
looks at ACLR. What about patients
who had surgery down the line for meniscal tears, OA, etc that all
resulted from the primary ACLR? These
questions are unknown.
So in considering this study, we must consider all these
factors. Based on the above, what does
this tell us clinically? We do know that
our patients are at greater risk for second ACLR if:
- They are younger – hence why
it is important to ensure we are incorporating injury prevention
techniques to address “root cause” of the primary ACL injury
- If they have surgery at an
academic institution – several studies correlate outcomes to frequency or
number of ACLR performed by the surgeon.
Therefore the more a surgeon has done, typically correlates to
improved outcome.
- Use of allograph can lead
to higher risk of 2nd ACLR
Considering previously posted articles, you should also
determine the “root cause” for the non-contact ACL injury and address the
psychology of the injury as well.
References:
Wasserstein D, Khoshbin A, Dwyer T, Chahal J, Gandhi R,
Mahomed N, Harris D. “Risk Factors for
Recurrent Anterior Cruciate Ligament Reconstruction: A Population Study in
Ontario, Canada, With 5 Year Follow Up”.
Am j sport med. 41:2000-2107. 2013.
Brophy, R; Schmitz, L; Wright, R; Dunn, W; Parker, R;
Andrish, J; McCarty, E; Spindler, K.
“Return to Play and Future ACL Injury Risk After ACL Reconstruction in
Soccer Athletes From a Multicenter Orthopaedic Outcomes Network (MOON)
Group”. Am j sports med. 40:2517-2522, 2012.
Holm, I; Oiestad, B; Risberg, M; Gunderson, R; Aune, A. “No Difference in Prevalence of
Osteoarthritis or Function After Open Versus Endoscopic Technique for Anterior
Cruciate Ligament Reconstruction: 12 Year Follow-up Report of Randomized
Controlled Trial”. Am j sports med. 40:2492-2498, 2012
McCullough, K; Phelps, K; Spindler, K; Matava, M; Dunn, W;
Parker, R; Reinke, E. “Return to High
School – and College-Level Football After Anterior Cruciate Ligament
Reconstruction: A Multicenter Orthopaedic Outcomes Network (MOON) Cohort
Study. Am j sports med. 40:2523-2529, 2012
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