Return to sport after anterior cruciate ligament reconstruction in
professional soccer players
S. Zaffagninia, A. Grassia, G.M. Marcheggiani Mucciolia,⁎, K. Tsapralisb, M. Riccib, L. Bragonzonia,
S. Della Villab, M. Marcaccia
aII Clinica Ortopedica e Laboratorio di Biomeccanica ed Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, Italy
bIsokinetic FIFA Medical Centre of Excellence, Bologna, Italy
a b s t r a c ta r t i c l ei n f o
Received 19 September 2013
Received in revised form 12 January 2014
Accepted 3 February 2014
Anterior cruciate ligament
Professional soccer players
Background: To investigate time to return to sport and rate of professional sport activity in a homogenous
group of competitive soccer players 4 years after anterior cruciate ligament (ACL) reconstruction and
Methods: Twenty-one male professional soccer players (mean age 22.9 ± 5.4 years) underwent non-anatomical
double-bundle autologous hamstring ACL reconstruction and followed the same rehabilitative protocol. Clinical
evaluation wasperformedpreoperativelyandat3,6 and 12-monthfollow-up.Data regarding return to trainand
official match, sport activity, complications and revision surgeries were collected at 4-year follow-up.
Results: Laxity test (KT-2000) and total KOOS mean score resulted in a significant improvement from the
preoperative status to the 12-month follow-up (p b 0.0001). The KOOS mean value showed a significant
progressive improvement from the preoperative status to 6-month follow-up (p = 0.0010) as well, while
values collected at 6 and 12-month follow-up were comparable (p = 0.2349). Returned to official matches
186 ± 53 days after surgery. After 12 months, 95% came back to the same activity level performed before injury.
Four years after ACL reconstruction, 15 patients (71%) were still playing competitive soccer. One patient (5%)
underwent ACL failure and subsequent revision.
Conclusions: The ACL reconstruction with the presented technique followed by patient-tailored rehabilitation,
allowed 95% and 62% professional male soccer players to return to the same sport activity 1 year and 4 years
after surgery respectively. However, 71% were still able to play competitive soccer at final follow-up. Clinical
scores were restored after 6 months.
Level of evidence: IV, case series.
© 2014 Elsevier B.V. All rights reserved.
The time to return to play and the ability to continue sport activity
with time are two important outcomes after anterior cruciate ligament
(ACL) reconstruction, especially in young sportsmen. Nevertheless no
consensus is available regarding the optimal rehabilitation length 
when considering the outcomes related to single sports. In 2011 a
systematic review by Warner et al. , evaluating sport-specific
outcomesafterACL reconstruction, reportedonlythreestudiespresent-
ing the results in soccer players [4–6]. The authors concluded that
“identifying sport-specific differences in ACL reconstruction outcomes
in athletes could lead to more effective rehabilitation programs for all
these athletes after surgery” and it will “provide orthopedic surgeons
the ability to accurately inform patients about what they should plan
to expect after surgery in terms of performance level and timing of re-
turn to sport” , thus underlying the need for further sport specific
studies. Furthermore, different interpretations have been attributed to
the “return to sport” outcome, ranging from return to perform sport-
specific gestures, restore pre-injury activity level, return to train or re-
turn to official match. Often, the precise definition is not even reported.
The main objective of this study was to report the time to return to
sport after ACL reconstruction in a homogenous group of competitive
football players treated with the same surgical technique and rehabilita-
tive programme and the rate of sport activity four years after the surgery.
The Knee 21 (2014) 731–735
⁎ Corresponding author at: Clinica Ortopedica e Traumatologica II — Lab. di Biomeccanica,
E-mail address: firstname.lastname@example.org (G.M. Marcheggiani Muccioli).
0968-0160/© 2014 Elsevier B.V. All rights reserved.
Contents lists available at ScienceDirect
2. Material and method
ing inclusion criteria were enrolled in the study:
• ACL lesion; and
• male professional soccer player,involved in competitive sport activity
more than 4 days per week on regular bases and attending the main
divisions of Italian Soccer League.
Exclusion criteria were:
• posterior cruciate ligament (PCL) lesion;
• grade III medial collateral ligament (MCL) lesion;
• lateral collateral ligament (LCL) lesion;
• unstable contralateral knee;
• systemic or local infection; and
• lower limb malalignment requiring surgery.
Among the overall 29 patients, 21 were considered eligible for this
study. All of them underwent ACL reconstruction by two senior sur-
geons (X.X. and X.X.) and subsequently started a patient-specific reha-
bilitation protocol at the same center.
2.1. Surgical technique
ACL reconstruction was performed in all patients according to the
non-anatomical double-bundle technique described by Marcacci et al.
, withmodificationsintroduced by Zaffagniniet al. . Thetechnique
is well described in the publications cited above, what follows is a brief
summary of the most important surgical steps.
Autologous semitendinosus and gracilis tendons(ST/G) from the ip-
silateral limb were harvested maintaining tibial insertion.
One single tibial tunnel was performed starting close to the MCL
with an exit point on the posteromedial aspect of the native ACL
footprint. One femoral tunnel was performed from the medial portal
with the knee flexed to approximately 120°, from anatomical postero-
lateral bundle insertion, directed above the end of the lateral femoral
epicondyle, 5 mm from the “over-the-top” position. After a lateral
incision, the tendons were passed “over-the-top”, than from outside in
the femoral tunnel and back again in the tibial tunnel to obtain a
and the anteromedial and posterolateral bundle fixed at 90° and 15°
with metal staples.
2.2. Rehabilitation protocol
No brace was used. After the first clinical examination after surgery,
performed approximately at week one, patients started gym and pool
sessions, aimed to improve pain, swelling, range of motion (ROM),
proprioception, strength and aerobic fitness. Early sport-specific exer-
cises designed for football players were performed as well.
The final phases of rehabilitation were performed on a soccer
trainer. This phase is referred as “on-field rehabilitation” (OFR) . OFR
was allowed if the patient presented no knee laxity, no giving-way
episodes during previous phases, minimal pain, minimal effusion, com-
plete ROM, isokinetic maximal peak torque deficit b20% between limbs
Details of previous and concurrent procedures are presented as number of patients and
Contralalteral ACL reconstruction
Ipsilateral partial medial meniscectomy
Ipsilateral partial lateral meniscectomy
Medial meniscus suture
Lateral meniscus suture
Statistical analysis of differences of the clinical scores along the various follow-up
Clinical outcome scores
3 M FU
3 M FU to
6 M FU
6 M FU to
12 M FU
12 M FU
Total KOOS score
All values are expressed as mean ± standard deviation. Significance is set at P b 0.05. PO,
pre-operative; 3M, 3 months; 6M, 6 months; 12M, 12 months
Fig. 1. The curve reports the KOOS values along the different follow-up evaluations.
Details of demographics, return to activity and follow-up are presented as mean ±
standard deviation and range. Details of rehabilitation sessions are presented as median
and interquartile range.
Demographic, rehabilitative and follow-up details
Age at surgery (years)
Age at final follow-up (years)
Final follow-up (month)
Knee involved (Right/Left)
Time from injury to surgery (days)
Time from surgery to rehabilitation (days)
Time from surgery to on-field training
Time from on-field training to training
with team (days)
Time from surgery to first
official match (days)
11 (52%)/10 (48%)
N. gym sessions
N. pool sessions
N. on-field sessions
N. total sessions
S. Zaffagnini et al. / The Knee 21 (2014) 731–735
measured with isokinetic dynamometers (Genu3 Easytech, Florence,
Italy) and the ability to run on the treadmill at 8 km/h for more than
10 min . Each OFR session lasted 90 min, 2 to 5 days a week; the pro-
gression of each type of exercises followed principles of strength train-
ing, conditioning and increased functional demand with respect to
musculoskeletal and neuromechanical components involved in the
OFR for football players was divided in five phases, and the progres-
sion occurred only when exercises of each phase were comfortable,
coordinated, tolerable, and without swelling or decreased ROM.
On-going knee examinations were performed at the beginning of
rehabilitation and every 2 to 4 weeks during the whole rehabilitative
period, in order to detect knee malfunctions and monitor the prog-
ression through rehabilitative protocol.
2.3. Follow-up evaluation
ation, with bilateral antero-posterior weight-bearing and a lateral view
in 30° of flexion of the involved knee. A pre-operative MRI was per-
formed to evaluate ligaments, menisci and cartilage status.
Clinical objective evaluation was performed preoperatively and
12 months after surgery by two independent orthopedic surgeons
who did not take part in the surgery, using the objective a KT-2000™
arthrometer (MedMetric, San Diego, CA, USA) for laxity measurements.
Patients were clinically evaluated preoperatively and at 3, 6 and
12 monthsafter surgery by means of the Knee injury and Osteoarthritis
Outcome Score (KOOS). This is a patient-reported subjective outcome
scale, with different subscales: pain, symptoms, function in daily living
(ADL), function in sport and recreation (Sport\Rec) and knee-related
quality of life (QOL).
Four years after the ACL reconstruction all patients were reviewed,
and data regarding sport activity, new injuries and revision surgeries
were collected. Particularly, all the patients were questioned if they
were still able to play soccer, and in case of negative response, the
causes were investigated.
Regarding rehabilitative protocol, number of sessions performed in
gym,pool and play-field was recorded. The total length of rehabilitative
rehabilitative sessions and return to training with the own team. The
gap between surgery and the beginning of rehabilitation was recorded
as well. The time to return to on-field training, to training with team
and to official match was collected starting from surgery.
2.4. Statistical analysis
The statistical analysis was performed using Analyse-it-2.00
(Analyse-it Software, Ldt, Leeds, UK). Statistical comparison between
the preoperative and follow-up parametric scores was performed
using paired Student's t-test, while unpaired Student's t-test was used
to compare parametric variables between subgroups. The population
study was tested for normal distribution before t-test was applied.
Differences between multiple scores were performed using the 1-way
ANOVA test. Correlation analysis was performed using Spearman test.
The life table survival analysis was used to evaluate cumulative rates
of returning to on field rehabilitation, train, and official match. The
level of significance was set at p b 0.05. Results are expressed using
mean values ± standard deviation (SD) for parametric values and
median ± interquartile range (IQR) for non-parametric values.
Approval of the study was obtained from the institutional review
board. Informed consent complied with European Union laws and was
signed by the patient before enrolment.
All patients (100%) were available for on-going clinical evaluations and at the 4-year
follow-up. The mean age at time of surgery was 22.9 ± 5.4 (Table 1). Four patients
(19%) had a history of medial or lateral partial meniscectomy on the interested knee
and three (15%) of contralateral ACL reconstruction, while 12 patients (57%) underwent
at least one concurrent procedure combined to ACL reconstruction (Table 2).
The side-to-side difference in manual maximum displacement test performed with a
KT-2000™ arthrometer revealed a significant difference between the pre-operative and
the 12-month follow-up status (7.4 ± 0.9 mm vs. 1.4 ± 1.9 mm; p b 0.0001).
The total KOOS scores resulted in a significant improvement from the preoperative
status to the 12-months follow-up (Table 3). The mean value showed a progressive im-
provement from the preoperative status to 3 months (p = 0.0003) and from 3 to
6 months (p = 0.0010) as well, whilethe valuescollected at 6 and 12 monthswere com-
parable (p = 0.2349) (Fig. 1). Therefore the KOOS score reached the plateau level since
pared to the other subscales, although at 3, 6 and 12 month follow-up evaluations they
were similar (Fig. 2), thus showing a higher improvement. No significant differences in
Fig. 2. The curves report the trend of the various KOOS subscales at different follow-up
evaluations. Means ± standard deviations are reported as well.
The return to activity endpoints from 2 to 8 months are reported as 0 to 1 ratio and confidence interval.
Return to sport activity after ACL reconstruction
Time From surgeryto on-field rehabilitationFrom surgery to training with teamFrom surgery to first match
RatioCI (95%) RatioCI (95%)Ratio CI (95%)
Mean value (days)
S. Zaffagnini et al. / The Knee 21 (2014) 731–735
clinical scores were found between patients with isolated or combined ACL reconstruc-
tion, or between patients with intact or deficient meniscus.
After 12 months from the ACL reconstruction, all patients except one (95%) returned
to the same professional sporting level performed before injury. This patient was able to
return to play competitive soccer, but in a lower division.
Regarding the details of rehabilitative protocol, the mean duration was 157 ±
49 days, and the mean number of rehabilitative sessions was 73 (56–109). Return to offi-
cial match was recorded 186 ± 53 days after surgery. The ratio was 0.048 at 4 months,
0.190 at 5 months, 0.429 at 6 months and 0.619 at 7 months. Regarding return to train
with team, at 6 months most of the patients (rate 0.762) achieved the goal yet
(Table4).Theprogress ofthe returntotrainandofficialmatchappearsto show aprogres-
sive and similar trend, while return OFR appears to show a quicker trend (Fig. 3).
Regarding revision surgery, one year and a half after the ACL reconstruction one
patient(5%) experienced a new ACL lesionwhen heincurreda non-traumaticknee sprain
that occurred during a soccer match. The patient underwent ACL revision with Achilles
tendon allograft and successfully returned to play after 8 months.
At the final review four years after ACL reconstruction, 15 patients (71%) were still
playing competitive soccer, 13 (62%) at the same pre-injury professional division, and
two (9%) in a lower division compared to the pre-injury status, due to issues not related
to kneeperformance. Ofthe six patients that abandoned their soccer career, the mainrea-
sonwas relatednot toknee statusbutto personal issues (Table5).Furthermore the ageat
final follow-up of retired athletes were significantly higher compared to active players
(30.4 ± 7.2 vs 25.5 ± 4.0; p = 0.0311). Despite this, all the retired players were still
involved in non-contact light sport activities (jogging, swimming and gym) at the final
In the present study the outcomes of a homogenous group of male
professional soccer players, who underwent ACL reconstruction with
the same technique and rehabilitative protocol, are presented using a
validated clinical score and precise definition of “return to sport”.
Regarding the latter outcome, a 2011 meta-analysis of Arden et al.
 reported 7.3 (range 2–24) months as the mean time needed to
return to sport in general population, even though different end-points
were used. Few studies evaluated this outcome specifically in soccer
players. Data regarding 55 male soccer players extrapolated from the
Multicenter Orthopaedic Outcomes Network (MOON) database, mainly
treated with BPTB autograft, reported a mean time to return to play of
10.2 ± 7.3 months, although the outcome was not clearly defined. In
a retrospective report of 36 Professional First Italian Division players
who underwent ACL reconstruction using different surgical techniques,
the mean time to return to official match was 231 ± 134 (range
77–791) days . The analysis of UEFA elite male soccer players
showed a mean time to return to official match of 224 ± 75 days for
43 European players and 252 ± 80 days for 20 Swedish players .
The latter study reported also the “return to train” outcome, which
was respectively 201 ± 68 and 203 ± 70 days for the two groups. The
present study, reporting a mean return to train of 169 ± 49 days and
a mean return to official match of 186 ± 52 days, seemed to show a
slightly shorter recovery compared to sport-specific case series. This
finding is also strengthened by the evidence of full recovery of the
KOOS at 6 months follow-up yet. Furthermore return to official match
is reported already between the 3rd and 4th month in several athletes,
with almost 43% reachingthetarget at the6th month,compared to 24%
and 32% for European and Swedish players respectively. This finding
could be explained by the athlete-tailored rehabilitation program,
combined to an effective double-bundle surgical technique [8,12]. In
the soccer players' case series [6,11,13] the impact of single or double-
bundle techniques was not evaluated, while, regarding graft choice, no
difference was reported between the hamstrings and BPTB. Regarding
the rehabilitative program, the presented method based on functional
goals instead of temporal criteria, allows the player to progress to the
rehabilitation phases on the basis of individual responses, leading to
different times in the achievement of final goals and with a different
number of sessions . Furthermore the on-field-rehabilitation
designed with sport-specific gestures is presumed to facilitate the
reduction of fear of relapse, which has been reported to be a not
negligible issue after ACL reconstruction . These features could
have contributed to faster recovery compared to the other case series;
nevertheless, it should be taken into account that return to match
could be influenced by several non-medical factors, e.g. coach selection,
off-season holidays or transfer.
The other primary outcome of ACL reconstruction is the rate of
return to sport at short–medium term. The same meta-analysis of
Arden et al.  reported a pooled return to sport rate of 82%, while
63% at pre-injury level; furthermore only 44% returned to competitive
sport. This meta-analysis however evaluated general population, with
different sports, activity level, demographic characteristics, and
follow-up. In particular higher return to sport rates are found in the
studies withlessthana 2-year follow-up, suggestingthat while athletes
initially return to higher-level sport participation postoperatively, this
participation is not maintained in the long term.
Similar trend, but with different rates was described for soccer
, 76% and 38% at 1 and 7.2 years respectively in the MOON database
, and 26% at 7 years in the Roos et al. report . In the present
study the rates of return to soccer were 100% and 71% at 1 year and
4 years respectively; the rates decreased to 95% and 62% if the return
to professional soccer level is considered . The rate is more similar to
the high-motivated elite European players, rather than the heteroge-
neous soccer players of the MOON cohort. Considering the athletes
that abandoned their sport career, it is noteworthy how in the present
study the main reasons were personal issues, aging and other medical
cision to stop sport activity. In fact only one patient abandoned soccer
termining career abandonment probably due to the impossibility of
maintaining or improving the prospective of a prolific soccer career.
Nevertheless, all the retired players were still involved in non-contact
light sport activities (jogging, swimming and gym). Regarding graft rup-
ture and revision surgery, thereported 3% rate in the MOON cohort does
not differ substantially from the 5% reported in the present study .
Fig. 3. The trend of return to activity endpoint rates are reported along various time
Details of sport activity at 4-year follow-up are presented as number of patients and
Sport activity at 4-year follow-up
Still playing soccer
Supended soccer activity
Problems related to the involved knee
Other physical problems
Career end (due to age)
S. Zaffagnini et al. / The Knee 21 (2014) 731–735
When considering the patients' characteristics, the age at surgery of Download full-text
the present study (22.9 years) does not differ substantially from what
was reported by other authors (22.9–26.2 years)  and the KOOS
values were similar to those reported in the Scandinavian ACL Registry
 at pre-operative status but higher at 1 year, probably due to the
high level sport practice with respect to the Scandinavian ACL Registry.
Globally, the outcomes at short–mid term obtained with the
presented original technique are encouraging, despite the high rate of
previous or concurrent meniscectomies, that is a well known risk factor
for bad outcomes and knee osteoarthritis .
This study has several limitations. Primarily the sample size is small,
although the other series reported similar number of patients, and the
ity to continue sport activity. Secondly, the high percentage of previous
or concurrentmeniscectomies could have biased theresults, but in clin-
ical practice coupled ACL and meniscal lesions, particularly in high im-
pact sports athletes, are a very common event so the presented case
series is more resembling to sports athlete population. Lastly, the lack
of radiographic control does not allow detecting eventual osteoarthritis
degeneration, and 4 years could not probably be sufficient to produce
degenerative changes is such young population.
The ACL reconstruction with non-anatomical double-bundle
hamstring technique, combined with a patient-tailored target-based
rehabilitation, allowed 95% and 62% of professional male soccer players
to return to thesame professional sport activity 1 year and 4 years after
surgery respectively. However, overall, 71% were still able to play
competitive soccer at any level at final follow-up. The clinical scores
were restored to pre-injury status since 6 months, while return to
play in official match was reported 186 ± 52 days after surgery. Failure
one patient (5%).
Conflict of interest
The authors declare no personal or financial conflict of interests
during the study execution and manuscript preparation.
The authors are grateful to Costanza Musiani, MD and Giada Lullini,
MD for their support.
 van Grinsven S, van Cingel RE, Holla CJ, van Loon CJ. Evidence-based rehabilitation
following anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol
 Della Villa S, Boldrini L, Ricci M, Danelon F, Snyder-Mackler L, Nanni G, et al. Clinical
outcomes and return-to-sports participation of 50 soccer players after anterior cru-
ciate ligament reconstruction through a sport-specific rehabilitation protocol. Sports
 Warner SJ, Smith MV, Wright RW, Matava MJ, Brophy RH. Sport-specific outcomes
after anterior cruciate ligament reconstruction. Arthroscopy 2011;27:1129–34.
 Roos H, Ornell M, Gardsell P, Lohmander LS, Lindstrand A. Soccer after anterior
cruciate ligament injury—an incompatible combination? A national survey of
incidence and risk factors and a 7-year follow-up of 310 players. Acta Orthop
 von Porat A, Roos EM, Roos H. High prevalence of osteoarthritis 14 years after an
anterior cruciate ligament tear in male soccer players: a study of radiographic and
patient relevant outcomes. Ann Rheum Dis 2004;63:269–73.
 Walden M, Hagglund M, Magnusson H, Ekstrand J. Anterior cruciate ligament injury
in elite football: a prospective three-cohort study. Knee Surg Sports Traumatol
 Marcacci M, Molgora AP, Zaffagnini S, Vascellari A, Iacono F, Presti ML. Anatomic
double-bundle anterior cruciate ligament reconstruction with hamstrings. Arthros-
 Zaffagnini S, Bruni D, Marcheggiani Muccioli GM, Bonanzinga T, Lopomo N, Bignozzi
S, et al. Single-bundle patellar tendon versus non-anatomical double-bundle
hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum
follow-up. Knee Surg Sports Traumatol Arthrosc 2011;19:390–7.
 Roi GS, Creta D, Nanni G, Marcacci M, Zaffagnini S, Snyder-Mackler L. Return to offi-
cial Italian First Division soccer games within 90 days after anterior cruciate liga-
ment reconstruction: a case report. J Orthop Sports Phys Ther 2005;35:61–6.
 Ardern CL, Webster KE, Taylor NF, Feller JA. Return to sport following anterior
cruciate ligament reconstruction surgery: a systematic review and meta-analysis
of the state of play. Br J Sports Med 2011;45:596–606.
 Roi GS, Nanni G Tencone F. Time to return to professional soccer matches after ACL
reconstruction. Sport Sci Health 2006;1:142–5.
 Zaffagnini S, Bruni D, Russo A, Takazawa Y, Lo Presti M, Giordano G, et al. ST/G ACL
reconstruction: double strand plus extra-articular sling vs double bundle, random-
ized study at 3-year follow-up. Scand J Med Sci Sports 2008;18:573–81.
 Brophy RH, Schmitz L, Wright RW, Dunn WR, Parker RD, Andrish JT, et al. Return to
play and future ACL injury risk after ACL reconstruction in soccer athletes from the
Multicenter Orthopaedic Outcomes Network (MOON) group. Am J Sports Med
 Kvist J, Ek A, Sporrstedt K, Good L. Fear of re-injury: a hindrance for returning to
sports after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol
 Granan LP, Forssblad M, Lind M, Engebretsen L. The Scandinavian ACL registries
2004–2007: baseline epidemiology. Acta Orthop 2009;80:563–7.
 Roos H, Lindberg H, Gardsell P, Lohmander LS, Wingstrand H. The prevalence of
gonarthrosis and its relation to meniscectomy in former soccer players. Am J Sports
S. Zaffagnini et al. / The Knee 21 (2014) 731–735