AJSM PreView, published on February 11, 2014 as doi:10.1177/0363546513519951
Effects of Prior Knee Surgery
on Subsequent Injury, Imaging,
and Surgery in NCAA Collegiate Athletes
Caitlin M. Rugg,* MS, Dean Wang,* MD, Pamela Sulzicki,y MS, ATC, and Sharon L. Hame,*z MD
Investigation performed at the Department of Orthopaedic Surgery,
David Geffen School of Medicine at UCLA, Los Angeles, California, USA
Background: High school and professional athletes with a history of orthopaedic surgery have decreased career lengths and are
at a greater risk for reinjury compared with their peers. It is unknown whether the same risk applies to intercollegiate athletes.
Purpose: To determine the effect of prior knee surgery in National Collegiate Athletic Association (NCAA) Division I athletes in the
United States.
Study Design: Cohort study; Level of evidence, 3.
Methods: Division I athletes who began participation in collegiate athletics at a single institution from fall 2003 to spring 2008
were identified. Athletes with a history of orthopaedic surgery were identified through preparticipation evaluation forms. Data
on the number of seasons and games played, number of days missed, diagnostic imaging, athletic injuries sustained, and surgical
operations during college were collected through medical records and the Sports Injury Monitoring System (SIMS).
Results: During the 5-year study period, 456 athletes completed preparticipation evaluation forms. Of these, 104 athletes (22.8%)
had a history of orthopaedic surgery (Ortho group). Forty-eight (10.5% of all athletes) had a history of knee surgery (Knee group),
16 (3.5%) had a history of anterior cruciate ligament reconstruction (ACL group), and 28 (6.1%) had a history of multiple surgeries
(Multiple group). Days missed per season due to any injury and due to knee injury were increased for all surgical groups compared
with controls (P \ .016). The rate of knee injury and knee surgery while in college was significantly increased for all surgery
groups. Athletes in the Knee and ACL groups were 6.8- and 19.6-fold more likely to sustain a knee injury and 14.4- and
892.9-fold more likely to undergo a knee surgery during their collegiate careers compared with controls (P \ .001). The number
of MRIs per season were 0.83 for the Knee group (P \ .001), 1.29 for the ACL (P = .009), and 0.97 for the Multiple group (P \ .001),
compared with 0.37 for controls. Average career length and percentage of games played were not significantly different between
any of the surgery groups compared with controls.
Conclusion: Athletes who had a history of knee surgery before participation in collegiate athletics miss more days due to injury,
have increased rates of knee injury and knee surgery, and require more MRIs during their collegiate careers than their peers.
Keywords: knee; surgery; collegiate; anterior cruciate ligament; athlete; imaging; prior injury; sports; return
Knee injuries are among the most common injuries sustained by high school and collegiate athletes and can
have devastating results for individual athletes and the
team.8-10,12,22,24 In the 2005-2006 and 2006-2007 school
years, knee injuries made up 15.2% of all high school
sports-related injuries.9 Football, women’s soccer, and
women’s gymnastics had the highest risk of knee injury
in high school sports.24 In addition, Rechel et al20 reported
that approximately half of all high school sports injuries
that require orthopaedic surgery involved the knee. Most
of these were complete ligament tears that medically disqualified athletes for the season.
In recent years, an increasing number of collegiate athletes are entering college with a history of anterior cruciate
ligament (ACL) tears, while more collegiate athletes are
experiencing ACL tears.8,12 These athletes may have
remaining functional deficits after surgery, which may predispose them to injuries when they enter college.10,11,16
Reinjury and contralateral injury after knee surgery are
concerns for players and coaches alike. It has been demonstrated that patients with a history of ACL injury are at
z
Address correspondence to Sharon L. Hame, MD, Department of
Orthopaedic Surgery, David Geffen School of Medicine at UCLA, CHS
76-119, 10833 LeConte Avenue, Los Angeles, CA 90095-6902, USA
(e-mail: shame@mednet.ucla.edu).
*Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
y
Athletic Department, University of California–Los Angeles, Los
Angeles, California, USA.
The authors declared that they have no conflicts of interest in the
authorship and publication of this contribution.
The American Journal of Sports Medicine, Vol. XX, No. X
DOI: 10.1177/0363546513519951
Ó 2014 The Author(s)
1
2
Rugg et al
increased risk of subsequent ACL rupture on both the
reconstructed and contralateral sides.2,7,17,21,23 Bourke
et al2 reported a 14% and 23% risk of tearing either ACL
after 5 and 15 years, respectively, after reconstruction
with an autologous graft. Female sex and return to high
activity may also predispose an athlete to rerupture.7,17,23
Similarly, an increasing number of collegiate athletes are
entering college with a history of meniscal tears. While
young athletes have improved outcomes in meniscal repairs
compared with older patients, reoperation rates are still
substantial.13,18,25 In a meta-analysis, 3.9% of partial meniscectomies and 20.7% of arthroscopic meniscal repairs
required reoperation within 10 years of the index surgery.18
Currently, little is known about the effects of knee surgery
in high school athletes and how it may affect their collegiate
athletic careers. Thus, the goal of this study was to determine
the athletic and medical outcomes in National Collegiate
Athletic Association (NCAA) Division I athletes with a history
of knee surgery at a single institution in the United States.
MATERIALS AND METHODS
Institutional review board approval for this study was
obtained. Athletes who underwent their initial preparticipation evaluation (PPE) and who began participation in
10 sports from fall 2003 to spring 2008 at our institution
were eligible for the study. Five men’s teams (football,
baseball, volleyball, basketball, and soccer) and 5 women’s
teams (softball, gymnastics, volleyball, basketball, and soccer) were included in the study. Eligible athletes were
identified using the institution sports archives and athletic
training room records. All athletes underwent their first
PPE before collegiate athletic participation by licensed
physicians, and surgical histories, including any orthopaedic surgery, were identified. Returning athletes during the
study period were not included in the study.
Sport played, seasons played, and games played were elicited from the sports archives. Data on injury type and days
missed due to injury were recorded from the Sports Injury
Monitoring System (SIMS; FlanTech, Inc, Iowa City, Iowa,
USA). In this system, athletic trainers recorded any medical
concern as an injury if it was managed for more than 10
days and/or resulted in restriction in activity. Medical
records and SIMS data were cross-referenced for diagnostic
imaging and surgeries performed during college. Redshirt
athletes, who are limited to less than 30% of competitions,
were included for complete practice exposure data.
Athletes were classified into different groups for comparison. The control group consisted of all athletes without
a history of orthopaedic surgery before first collegiate PPE,
whereas those athletes with an orthopaedic surgery before
first collegiate PPE made up the orthopaedic surgery
cohort (Ortho group). Within this group, subgroups of athletes with a history of any knee surgery (Knee group), ACL
reconstruction (ACL group), and multiple orthopaedic surgeries (Multiple group) were identified. Athletes could be
classified into 2 or more groups if they fulfilled the criteria.
Statistical analyses were performed with GraphPad Prism
5 (GraphPad Software, La Jolla, California, USA). Two-
The American Journal of Sports Medicine
tailed t tests and Mann-Whitney U tests were used to compare injury groups to control for parametric and nonparametric
distributions,
respectively.
Time-dependent
analyses were completed using the Kaplan-Meier method,
and curves were compared using the log-rank test. Dates of
the entering PPE were used as the starting dates, and the
last days of collegiate careers were censored if an athlete
did not sustain a knee injury or undergo a knee surgery
in college. Hazard ratios were calculated when comparing
injury group survival curves to that of the Control. Significance was predefined at P \ .05.
RESULTS
Demographic Data
From fall 2003 to spring 2008, there were 456 athletes from
10 sports at our institution who underwent an initial PPE
by a licensed physician (Table 1). Of these, 104 athletes
(22.8%) had a history of orthopaedic surgery, which constituted 25.8% of female and 21.3% of male athletes. The
sports with the highest percentage of incoming athletes
with a history of orthopaedic surgery were women’s gymnastics (59.3%), women’s soccer (29.4%), men’s soccer
(26.2%), and baseball (24.1%) (Figure 1). The sport with
the smallest percentage of athletes with surgery history
was softball (3.6%). Among the athletes with a history of
orthopaedic surgery, 48 (10.5% of all athletes) had a history
of knee surgery (Knee group). Sixteen (3.5%) had history of
ACL reconstruction (ACL group), and 28 (6.1%) had a history of multiple surgeries (Multiple group). Sports with the
highest percentage of incoming athletes with a history of
knee surgery were gymnastics (29.6%), women’s soccer
(21.6%), and women’s volleyball (14.3%). Other previous
surgeries involved the wrist and hand (16.3% of the Ortho
group), foot and ankle (16.3%), elbow (12.5%), and shoulder
(10.6%).
Participation Data: Seasons Played,
Games Played, and Days Missed
Average overall career length across all sports was 2.84
seasons. Average career length for controls was 2.86 seasons, compared with 2.50 seasons for the Knee cohort,
2.38 seasons for the ACL cohort, and 2.42 seasons for the
Multiple cohort. Although there was a trend toward
decreased career length in the surgery groups and specifically the Knee group (P = .059 vs controls), these were not
statistically significant (Table 2). In addition, there were
no differences in career length between men and women.
Athletes in the control group played an average of 57.4%
of games, while those in the Knee group played 54.4% of
games (P = .385). Female athletes with a history of knee
surgery played 53.2% of games compared with 59.8% for
female athlete controls. However, this difference was not
significant.
Athletes in the control group missed an average of 34
days per season due to any injury. In contrast, those in
the Knee and ACL groups missed 99 days (P \ .001) and
Vol. XX, No. X, XXXX
Effects of Prior Knee Surgery in NCAA Collegiate Athletes
3
TABLE 1
Demographics of NCAA Athletes With Prior Orthopaedic Surgery by Sporta
Prior Surgery Type, No. (%)
No. of Eligible
Athletes
Men’s sports
Football
Baseball
Soccer
Volleyball
Basketball
Women’s sports
Soccer
Softball
Volleyball
Gymnastics
Basketball
Athletes With Prior
Orthopaedic Surgery, No. (%)
301
142
58
42
34
25
155
51
28
28
27
21
64
27
14
11
8
4
40
15
1
6
16
2
(21.3)
(19.0)
(24.1)
(26.2)
(23.5)
(16.0)
(25.8)
(29.4)
(3.6)
(21.4)
(59.3)
(9.5)
Knee
Surgery
24
12
2
4
4
2
24
11
0
4
8
1
(8.0)
(8.5)
(3.4)
(9.5)
(11.8)
(8.0)
(15.5)
(21.6)
(0)
(14.3)
(29.6)
(4.8)
ACL
Reconstruction
6 (2.0)
2 (1.4)
0 (0)
2 (4.8)
2 (5.9)
0 (0)
10 (6.5)
4 (7.8)
0 (0)
2 (7.1)
3 (11.0)
1 (4.8)
Multiple
Surgeries
16
7
4
1
3
1
12
3
0
3
6
0
(5.3)
(4.9)
(6.9)
(2.4)
(8.8)
(4.0)
(7.7)
(5.9)
(0)
(10.7)
(22.2)
(0)
a
ACL, anterior cruciate ligament; NCAA, National Collegiate Athletics Association.
Figure 1. Percentage of incoming collegiate athletes with
a history of single (black) or multiple (gray) orthopaedic surgeries, by sport. Number of athletes per sport is listed in
parentheses. M, men’s; W, women’s.
Figure 2. Days missed per season due to any injury (black)
or knee injury (gray). Error bars represent standard error of
the mean. ACL, anterior cruciate ligament. *P \ .05 and
#
P \ .01 vs respective controls.
TABLE 2
Career Length of NCAA Athletes With a History of
Orthopaedic Surgery vs Controlsa
average of 7 days due to a knee injury per season, whereas
athletes in the Knee, ACL, and Multiple groups missed 45,
70, and 11 days, respectively, due to a knee injury (P \
.001 for all groups vs control). Figure 2 also shows days
missed for athletes with a history of any orthopaedic surgery for comparison. Knee injuries made up nearly half
of total days missed for the Knee and ACL groups. There
were no differences in days missed due to any injury or
knee injury between men and women.
Group
Control
Orthopaedic surgery
Knee surgery
ACL reconstruction
Multiple surgeries
Career Length,
Seasons, Mean 6 SD
2.86
2.79
2.50
2.38
2.42
6
6
6
6
6
1.20
1.20
1.22
1.36
1.26
P Value
(vs Control)
.62
.06
.12
.13
a
ACL, anterior cruciate ligament; NCAA, National Collegiate
Athletics Association; SD, standard deviation.
Survival Analysis: Rate of Knee Injury
and Knee Surgery
121 days (P = .016) per season, respectively, due to any
injury (Figure 2). Athletes in the control group missed an
Athletes in the Knee group had a 6.8-fold increased rate of
at least 1 knee injury compared with controls (95% confidence interval [CI], 3.73-12.43; P \ .001) (Figure 3A).
4
Rugg et al
The American Journal of Sports Medicine
Figure 3. Kaplan-Meier survival analysis of athletes who (A) sustained a knee injury or (B) underwent a knee surgery during their
collegiate careers. ACL, anterior cruciate ligament. *P \ .01 vs control.
Figure 4. Average number of (A) knee surgeries and (B) magnetic resonance images (MRIs) per season. Error bars represent
standard error of the mean. ACL, anterior cruciate ligament. *P \ .05 vs respective controls.
Furthermore, athletes in the ACL and Multiple groups had
a 19.6-fold (95% CI, 6.32-60.83) and 3.8-fold (95% CI, 1.847.66) increased rate of knee injury, respectively, compared
with controls (P \ .001).
The Knee group had a 14.4-fold (95% CI, 5.2-39.7)
increased rate of knee surgery compared with the control
group (P \ .001). Rate of knee surgery was also increased
for ACL athletes (892.9-fold; 95% CI, 112.4-7097.2) and
Multiple athletes (26.7-fold; 95% CI, 7.3-97.3) compared
with control athletes (P \ .001). Knee surgeries made up
83.3% and 92.3% of all orthopaedic surgeries received by
Knee and ACL athletes, respectively, compared with
34.4% in control athletes. Of note, there were no differences in the likelihood of knee injury or knee surgery
between male and female athletes during college.
Surgeries and Diagnostic Imaging per Season
Control athletes averaged 0.03 knee surgeries per athletic
season (Figure 4A). In contrast, athletes in the Knee, ACL,
and Multiple groups averaged 0.17, 0.24, and 0.21 knee
surgeries per season, respectively (P \ .001 for all groups
vs controls). Figure 4A also shows the number of knee surgeries for the Ortho group for comparison.
Control athletes averaged 0.37 magnetic resonance
images (MRIs) per season (Figure 4B). In contrast, athletes
in the Knee, ACL, and Multiple groups averaged 0.83, 1.29,
and 0.97 MRIs per season, respectively (P \ .001, .009, and
\.001 for Knee, ACL, and Multiple vs controls, respectively). Figure 4B also shows the MRIs performed for the
Ortho group for comparison. Control athletes averaged
1.04 radiographs per season, while Multiple athletes
required 1.51 radiographs per season (P = .044). There
was no significant difference between the Knee or ACL
groups versus controls for radiographs per season.
DISCUSSION
While past studies have examined outcomes of athletes
with a history of knee surgery entering high school and
professional sports, no study to date has reported on similar outcomes in NCAA Division I collegiate athletes. These
data are valuable to coaches, athletic trainers, physicians,
athletes, and parents both at the high school and collegiate
levels. Special challenges are present for Division I collegiate athletes. For many of the players, training intensity
of collegiate athletics is greatly increased compared with
high school athletics. Number and intensity of workouts
increase, along with the introduction of added demands
of college life. Given the paucity of literature regarding
the outcomes of Division I athletes with a history of knee
Vol. XX, No. X, XXXX
Effects of Prior Knee Surgery in NCAA Collegiate Athletes
5
surgery, this study examined the epidemiology of incoming
athletes at a single institution as well as their rate of
injury, rate of surgery, and other related medical outcomes
during their collegiate careers.
Among matriculating athletes during the 5-year period,
23% entered college with a history of an orthopaedic surgery. A tenth of incoming athletes had a history of knee
surgery, making the knee the most common previously
operated joint. This is consistent with rates reported in
studies of incoming professional athletes.3 Interestingly,
only 3.5% of athletes had a history of an ACL tear (2.0%
and 6.5% of male and female athletes, respectively).
Many who sustain an ACL tear in high school may have
been unable to pursue a Division I athletics career. This
phenomenon was demonstrated in a study by the Multicenter Orthopaedic Outcomes Network (MOON) group,15 in
which less than half of high school football athletes sustaining ACL reconstruction were able to return to their
previous level of athletic participation. Other factors that
may reduce the number of athletes with ACL injuries pursuing Division I athletics are the increased demand of collegiate athletics or less aggressive recruiting from college
coaches because of an athlete’s injury history. Presently,
the attitudes of college coaches with respect to injury history have not been studied.
In the current study, women’s gymnastics and women’s
soccer had the highest percentage of athletes with knee
surgery before college. Knee injury rates in high school
athletics have been found to be highest in football, women’s
soccer, and women’s gymnastics.24 In this study, 8.5% of
football athletes had a history of knee surgery, although
surgery type was not available. Comparably, at the professional level, 10.3% of football athletes enter the National
Football League (NFL) Combine with a history of meniscectomy, 8.2% have a history of knee arthroscopy, and
5.9% have a history of ACL reconstruction.
While there was a trend toward decreased career length
in the surgery groups, these trends were not significant.
Previously injured collegiate football athletes who participated in the NFL Combine had a reduced likelihood of
being drafted and a reduced longevity in the league.4 In
particular, players with a history of meniscectomy had
decreased longevity from 7.0 seasons to 5.6 seasons compared with matched controls. Furthermore, those who
had combined ACL/meniscus surgery had decreased longevity from 6.1 seasons to 4.0 seasons compared with
matched controls. Nevertheless, different positions in football have different physical stresses and requirements, and
thus the risk of an injury and its subsequent effects may be
position dependent.1,6,22 Of note, athlete attrition over 4
years was greater than 50% for all groups in this study,
including controls. While the present study was unable to
ascertain the cause of individual athlete attrition, medical
disqualification, personal reasons, transition to a professional career, or transfer to another university are common
reasons for discontinuing participation for athletes.
Percentage of games played was not statistically significant between surgical groups (Knee, ACL, and Multiple)
and controls, despite the substantial increase in injury
and surgery rates for the former. One plausible
explanation is the delay of surgeries until after the season,
allowing athletes requiring surgeries during college to participate at a level comparable with healthy athletes. A 7%
decrease in percentage games played for female athletes
with a history of knee surgery compared with control athletes was observed; while this was not significant, future
studies should investigate the role of sex in participation
after a surgery. A study of NFL athletes demonstrated
decreased games played for athletes who had had a meniscectomy or a combined meniscectomy/ACL reconstruction
but not for those who had received isolated ACL reconstruction.5 In this study, athletes who had a prior meniscectomy before entering college could not be ascertained.
The rate of knee injury during college was statistically
increased for all surgery groups compared with controls,
which is consistent with studies in high school athletes
and athletes sustaining ACL tears.7,10,17 DuRant et al8
demonstrated that knee injuries were more likely to occur
in athletes who had a history of knee injury or knee surgery. In this study, the Knee and ACL groups were 6.8fold and 19.6-fold more likely to sustain a knee injury
than were controls. Fewer than 20% of the ACL group completed 4 years of participation without sustaining a knee
injury. Serious injury is a predictor for worse quality of
life in collegiate athletes,14 and while the present study
looked at all minor and serious injuries, quality of life
may be a consideration as previously injured athletes are
looking forward to collegiate athletics. The risk of knee
surgery was increased for all surgical groups compared
with controls. However, analysis of athletes with a history
of non–knee-related orthopaedic surgery showed no difference in the risk of surgery compared with controls. Thus, it
appears that within the group of athletes with a history of
surgery, those with a history of knee surgery (and especially ACL reconstruction) truly have an elevated risk of
surgery. This is consistent with a study of high school athletes that showed joint-specific risks were related to prior
injury on that joint.8
Athletes with a history of surgery required more MRIs
and surgeries during college. The ACL group required 3
times as many MRIs per season compared with controls,
the majority of which were for the knee. In addition, both
ACL and Knee groups required more surgeries per season
compared with controls. Within the Ortho group, the risk
of surgery was not different from controls if the athlete
had not had a prior knee surgery. This suggests that the
Knee athletes within the Ortho group may have been contributing to the trends in increased medical intervention
that were observed.
Cost to the university is a significant concern for the
athletic department and the university. The current study
reveals significant increases in medical imaging and surgical intervention for athletes with a history of orthopaedic
surgery. It is also likely that these athletes require more
attention and therapy from the athletic trainers, physical
therapists, and sports psychologists. Interestingly, most
treatments received by collegiate athletes may be due to
non–time loss injuries, which were not included in the current analysis.19 Therefore, this study may not have captured the full effect that athletes with a surgery history
6
Rugg et al
have on treatment cost. In addition, athletes on scholarship who become medically disqualified due to orthopaedic
injury should be considered, since the university may be
responsible for their scholarship and medical treatment
throughout the athlete’s 4 years even if the athlete is not
participating.
There are a number of limitations to the current study.
The research was performed at a single institution, reducing the generalizability to the entire NCAA population. In
addition, this was a retrospective analysis of preexisting
data, and thus no causality can be determined. Data for
games played were available only for 86% of athletes.
The Sports Injury Monitoring System may not capture
every single event, but it is highly likely that major injuries to the knee and surgeries would be included. Of
note, redshirt years for an athlete were included in the
injury and surgery risk analysis; however, these athletes
participated in fewer competitions and thus may have
been at a decreased overall risk of injury. Research has
shown that risk of injury is 3-fold higher during competition than during practices in collegiate athletics, and risk
is even higher for contact sports such as football and soccer.9,20,22 Nevertheless, redshirt years were included for
complete exposure (including practices) and injury data.
Despite these limitations, this study demonstrated a significantly increased rate of knee injury and surgery during
a collegiate athletic career given a prior history of knee
surgery in a large cohort of Division I athletes. Moreover,
these athletes tend to miss more days due to injury compared with other athletes, although differences in career
length and games played were not significant. Future
work will include a cost-benefit analysis and prospective
data collection to more precisely examine any differences
between sex, sport, and surgery type.
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