KNEE

A medium to long-term follow-up of ACL reconstructionusing double gracilis and semitendinosus grafts

Andrea Ferretti • Edoardo Monaco •

Silvio Giannetti • Ludovico Caperna •

David Luzon • Fabio Conteduca

Received: 23 July 2009 / Accepted: 17 June 2010 / Published online: 3 July 2010

� Springer-Verlag 2010

Abstract This paper reports the results of our approach to

ACL tears and knee laxity, based on 30 years of experience

in ACL reconstruction with hamstrings and founded on the

following cornerstones: the use of doubled semitendinosus

and gracilis as a free graft; the use of an out-in technique for

femoral drilling and of very strong and stiff fixation devices;

the careful examination and repair or reconstruction of the

lateral compartment in selected patients; and the use of

unaggressive rehabilitation. We prospectively evaluated a

series of 100 consecutive patients who underwent ACL

reconstruction between 2001 and 2002. A clinical and

radiological follow-up was performed at a minimum of

6 years. After 6 years, the International Knee Documenta-

tion Committee score demonstrated good-to-excellent

results (A and B) in 98% of patients. However, arthrometric

results using the KT-1000 demonstrated that 6/80 patients

(7.5%) had [5 mm manual maximum side-to-side differ-

ence. The median Tegner activity score was 5 (range 1–9);

the median Lysholm score was 96 (range 81–100); and the

median subjective IKDC score was 94 (range 66–100). We

reported 6/80 failures as revealed by a 2? or 3? pivot-shift

test result and/or KT-1000 side-to-side difference of more

than 5 mm. The IKDC score revealed excellent results in all

women who underwent extra-articular tenodesis. Radio-

graphic evaluation demonstrated early signs of osteoarthritis

in 9% of patients.

Keywords Anterior cruciate ligament (ACL)

reconstruction � Extra-articular tenodesis � Hamstrings �Tunnel widening

Introduction

Anterior cruciate ligament (ACL) reconstruction is one of the

most frequently performed operations in orthopedic surgery.

Patellar tendon and hamstring tendons are the most com-

monly used graft choice for most surgeons—both options are

reliable and report comparable clinical and functional out-

comes with satisfactory mid- and long-term results in 80% to

more than 90% of patients [4]. The major benefit of using a

hamstring tendon graft is decreased donor-site morbidity, in

particular, there is less anterior knee pain and kneeling dis-

comfort thus resulting in fewer potential damages to the

extensor mechanism (extensor weakness, extension loss)

compared to bone-patellar bone-tendon grafts [4].

Our approach to ACL reconstruction is based on the fol-

lowing cornerstones: the use of doubled semitendinosus and

gracilis tendons dissected as free grafts; the use of very

strong and stiff, quite anatomical, devices implanted using an

out-in technique for femoral drilling; careful examination

and repair or reconstruction of the lateral compartment in

selected patients (severe rotatory laxity with a 3? pivot-shift

test result, revisions, high-risk athletes); and the use of

unaggressive rehabilitation with an extension brace for

2 weeks postoperatively. This initial precaution does not

affect the following steps of the rehabilitation, which

advances quickly with return to competitive sport in about

4–6 months.

The aim of this study was to prospectively evaluate our

present surgical technique to treat ACL tears and knee

laxity at 6 years follow-up in a series of 100 consecutive

A. Ferretti � E. Monaco � S. Giannetti � L. Caperna �D. Luzon � F. Conteduca

Department of Orthopaedics and Traumatology, Kirk Kilgour

Sports Injury Center, II School of Medicine, Sant’Andrea

Hospital, Sapienza University of Rome, Rome, Italy

E. Monaco (&)

Via D. di Buoninsegna 22, 00142 Rome, Italy

e-mail: edoardo.monaco@tin.it

123

Knee Surg Sports Traumatol Arthrosc (2011) 19:473–478

DOI 10.1007/s00167-010-1206-1

patients, operated by the same senior surgeon (A.F.) just

after the commercial availability of new fixation devices.

Clinical and radiographic results—especially the degree of

degenerative changes and bone tunnel widening—were

specifically evaluated and correlated with the functional

and stability status of the patients.

Materials and methods

Between 2002 and 2003, one hundred consecutive

patients who underwent an ACL reconstruction using a

hamstring tendon autograft were selected for this pro-

spective study and re-evaluated at a minimum of 6 years

postoperatively. Exclusion criteria were severe cartilage

damage (grade 3 or 4 according to the Outerbridge clas-

sification [29]), additional procedures to the cartilage

(autologous chondrocyte transplantation, microfractures,

etc.), open physes and surgery on the involved knee prior

to the injury.

An arthroscopically assisted two-incision technique

using doubled semitendinosus and gracilis tendon auto-

grafts was performed. A cortical fixation to the bone was

achieved on the femur using the SWING BRIDGE device

(Citieffe, Bologna, Italy) and on the tibia using the

EVOLGATE device (Citieffe, Bologna, Italy) [11]. A tight

fit of the graft in the bone tunnel was aimed for in all

patients. Among professional athletes with severe knee

laxity having a 2? or 3? pivot-shift test result, extra-

articular reconstruction was also performed (Coker Arnold

modification of the McIntosh technique [26]).

The postoperative rehabilitation was standardized for all

patients: the involved knee was placed in a full extension

brace for 2 weeks postoperatively with weight-bearing on

crutches as tolerated. Following the 2 weeks, progressive

range-of-motion exercises were encouraged. At 6 weeks

postoperatively, full weight-bearing without crutches and

without brace was permitted. From 2 to 4 months postop-

eratively, a muscle-strengthening program was prescribed

and between 4 and 6 months postoperatively, a gradual

return to specific athletic training was encouraged.

A 6-year follow-up examination was performed by the

same observer (S.G.) who was not involved in the initial

surgery.

The activity level was assessed using the Tegner activity

score [32]. In evaluating the functional status, the Lysholm

score [32] was used, whereas in evaluating the clinical

outcome, the International Knee Documentation Commit-

tee rating system (IKDC) [16] was used.

Patients underwent a standardized bilateral knee exam-

ination. Stability testing was performed using the Lachman

test, the pivot-shift test and the KT-1000 arthrometer

(Medmetric, San Diego, USA).

Weight-bearing comparative radiographs (A-P with

extended knee and lateral view) were obtained and evalu-

ated using Fairbank signs [9], Kellgren scores [21] and the

IKDC grading system [16].

Tunnel enlargement was determined with the method

described by L’Insalata et al. [23]. These measurements

were performed by a single examiner using a digital

calliper and a dedicated digital radiology software

(Centricity Imaging PACS/AW Suite, GE Healthcare IT).

The ratio between this average value and the intraopera-

tively determined tunnel diameter, according to medical

record, was used to assess the tunnel widening.

The Student t-test and analysis of variance (ANOVA)

were used to analyze the data for the patients in this series.

For power analysis, the alpha error was fixed at 5%

(confidence interval 95%) and the level of significance was

P \ 0.05. Statistical evaluation was performed using SPSS

for Microsoft Windows 7.0 (SPSS, Inc., Chicago, IL).

Results

At final follow-up, eight patients (8%) were lost to follow-up

and eighty patients (80%) returned for an evaluation that

included a thorough medical history and physical examina-

tion, a radiographic examination and a KT-1000 arthrometric

test. Eleven patients (11%) were evaluated using only the

rating scales obtained via telephone interview. One patient

was excluded after having suffered a serious accident that

occurred during the follow-up period; eventually, a full

recovery and return to the competitive level achieved before

injury was achieved.

At time of surgery, there were 68 men and 23 women

with a median age of 35 years (range 21–58). The median

follow-up time was 6 years (range 60–65 months).

The mean time between trauma and surgery was 7 days

(min 2, max 14) in the acute patients (25/100 patients) and

4 months (min 2, max 5) in the chronic patients (75/100

patients). A partial medial meniscectomy was performed in

11 patients, a partial lateral meniscectomy in 20 patients

and a partial medial and lateral meniscectomy in 7 patients.

Repair of the medial meniscus was performed in 4 patients.

In 23 of 100 patients, an extra-articular reconstruction was

performed with the above-mentioned technique.

The results of the Tegner score, Lysholm score and

subjective IKDC evaluation are summarized in Table 1.

A statistically significant difference was found com-

paring pre and postoperative functional scores (P = 0.001

for Tegner, Lysholm and IKDC).

No differences were detected for Lysholm and IKDC

activity scores comparing acute and chronic cases (n.s.),

while a significantly better result was found in acute cases

with respect to the Tegner score (P = 0.04). There were no

474 Knee Surg Sports Traumatol Arthrosc (2011) 19:473–478

123

differences in functional scores between patients with and

without meniscectomy at the time of surgery (n.s.). No

differences in functional scores were also found concerning

the use of the extra-articular reconstruction (n.s.) and

comparing male and female patients (n.s.).

At the preoperative arthrometric evaluation, the mean

KT-1000 arthrometer manual maximum side-to-side dif-

ference was 9 mm (range 6–12 mm).

At 6-year follow-up, instrumental laxity testing showed

a mean KT-1000 arthrometer manual maximum side-

to-side difference of 2.5 mm [range 0–8 mm (Table 2)].

No differences were detected for arthrometric results

comparing acute and chronic cases (n.s.) and comparing

patients with or without meniscectomy and patients with or

without extra-articular reconstruction (n.s.).

Results of the Lachman test, pivot-shift test and objec-

tive IKDC evaluation are summarized in Table 3.

No statistically significant differences were detected in

clinical results comparing acute and chronic cases (n.s.)

and comparing patients with or without meniscectomy and

extra-articular reconstruction (n.s.). However, better clini-

cal results were found in men with respect to female

patients (P = 0.01).

There were no intra- or postoperative complications

during the inpatient period. In no cases were revisions or

other surgeries performed during the follow-up period.

The results of radiographic evaluation are summarized

in Table 4.

Upon X-ray evaluation, a trend toward increased inci-

dence of joint degeneration was found in meniscectomized

knees (n.s.), while no correlation was found between acute

and chronic cases in patients with or without extra-articular

reconstruction (n.s.).

We found that the mean tunnel widening was 0.4 mm

(4.3% with a range of 0–2.2 mm) on the femoral side and

1.5 mm (16.9% with a range of 0–4 mm) on the tibial side. We

found tunnel widening on the femoral side in 12% of patients

and on the tibial side in 24% of patients. However, in only one

case did the tunnel diameter exceed 25% of the original size.

Although tunnel widening was detected in this study, patients

with femoral and tibial tunnel widening did not show worse

outcomes, neither concerning functional scores (Lysholm,

IKDC) nor concerning stability (KT-1000).

Discussion

In previous studies, tensile strength of Swing Bridge and

Evolgate fixation devices was demonstrated to be stronger

Table 1 Pre and postoperative results of the activity score and of the

functional results

Preoperative Final follow-up (6 years)

Lysholm 57 (40–68) 96 (81–100) P \ 0.05

Tegner 3 (1–5) 5 (1–9) P \ 0.05

IKDC subjective evaluation 58 (40–70) 94 (66–100) P \ 0.05

Table 2 Arthrometric results using the KT-1000 at 6-year follow-up

(manual maximum side-to-side difference)

KT-1000 (manual maximum side-to-side difference)

\3 mm 3–5 mm [5 mm

58/80 (72.5%) 16/80 (20%) 6/80 (7.5%)

Table 3 Pre and postoperative results of laxity test (values are

expressed in percentage of patients)

Preoperative (%) Final follow-up

(6 years) (%)

IKDC objective evaluation

Group A 0 72

Group B 0 27

Group C 30 1

Group D 70 0

Lachmann

- 0 87

? 100 13

Pivot-shift

- 0 72

? 4 27

?? 20 1

??? 76 0

Table 4 Results of radiographic evaluation (values are expressed in

percentage of patients)

6-year follow-up

IKDC score

Group A 86%

Group B 14%

Group C 0

Group D 0

Fairbank classification

Grade I 60%

Grade II 31%

Grade III 9%

Grade IV 0

Kellgren classification

Grade I 89%

Grade II 11%

Grade III 0

Grade IV 0

Mean tunnel widening

Femoral side 0.4 (0–2.2 mm)

Tibial side 1.5 (0–4 mm)

Knee Surg Sports Traumatol Arthrosc (2011) 19:473–478 475

123

and stiffer compared to other commercially available

devices [10–12, 24].

These technical improvements in fixation devices

allowed us to achieve a very stable knee at final follow-up

with a KT-1000 side-to-side difference of less than 5 mm

in more than 90% of patients. The efficacy of this tech-

nique is validated also by the low incidence of symptoms.

All patients in this series were satisfied with the operation

and no patients complained of pain or instability even

during strenuous sports activities. Moreover, even though

the devices used are both made of a titanium alloy and are

impacted on the cortical bone, no complications such as

ileotibial band friction syndrome and pain on the tibial side

have been reported. Also, in no patient has device removal

been needed.

The correct positioning of the graft is an important

factor in successful ACL reconstruction. In this series, a

standard tibial guide was used and positioned at 65�degrees with the probe of the guide placed at 7 mm in front

of the PCL. For the femoral tunnel placement, some

authors suggest the use of trans-tibial or anteromedial

portal access. We prefer the out-in technique that allows

the surgeon to orient the femoral tunnel in a more posterior

and anatomical position almost over the top position,

independently from the tibial tunnel position [31]. Con-

sidering the functional results, we believe that using a two-

incision out-in technique is quite safe with just an increased

minimal morbidity or in the case of extra-articular recon-

struction, not increased morbidity because the same second

incision is needed for the lateral plasty.

The first aim of the radiographic study was to determine

tunnel widening. Tunnel widening has been considered as a

major concern in ACL reconstructions with hamstring

tendon grafts [6, 18, 23]. We detected a femoral tunnel

widening in only 12% of patients using a suspension device

such as the Swing Bridge and in 24% of patients at the

tibial side, using an anatomical device such as the

Evolgate, with only one case exceeding 25% of the original

size. Based on these data, we assume that tunnel enlarge-

ment could be limited by using very strong and stiff

devices as previously demonstrated by Iorio et al. in a CT

study [19].

Moreover, many authors hypothesized that aggressive

rehabilitation protocols may be a potential factor for bone

tunnel enlargement, especially in reconstructions per-

formed with hamstring autografts [2, 14, 33]. Although the

use of the devices seem to strongly reduce the micro-

movements of the tendons inside the tunnels, thus pro-

moting Sharpey’s fibers formation, we use an unaggressive

rehabilitation utilizing a full extension brace for 2 weeks

postoperatively in order to better promote the biological

fixation. This rehabilitation protocol does not interfere with

the following steps of the rehabilitation and with the return

to sports activities in 4–6 months postoperatively. The

concept of enhanced integration of the graft into the tunnel

is indirectly confirmed by the fact that a very limited tunnel

enlargement was observed at 6-year follow-up.

However, no correlation was revealed between tunnel

widening and activity level, functional results and KT-1000

results. Therefore, our findings were generally in accor-

dance with literature [2, 5].

The development of osteoarthritis after ACL reconstruc-

tion is reported for all types of reconstructions. Explanations

are difficult (overconstrained grafts, nonanatomical proce-

dures, overuse in stable knees, meniscal lesions and personal

experience of the surgeon). Reports of joint space narrowing

in literature range from 12 to 78% [17].

Nine percent of patients reported grade III degeneration

according to Fairbank signs; only 14% of patients were in

group B according to the Kellgren scores; and all patients

were graded as A or B (normal or nearly normal) using

IKDC. In agreement with previous studies [14], we

detected a trend toward degeneration in patients with

medial meniscectomy (n.s.). No joint degeneration was

observed in chronic patients compared to acute patients nor

in patients without extra-articular reconstruction compared

to those with (n.s.).

Several anatomical and biomechanical studies demon-

strated the strict relationship between ACL and the cap-

sular lateral ligaments in controlling the rotatory stability

of the knee; and that in ACL tears, injuries of these liga-

ments often occur [20, 22]. The degree of involvement of

the lateral capsular ligaments could explain the difference

in rotatory laxity found in ACL tears, currently evaluated

by a pivot-shift ranging from 1? to 3?.

Recently, several authors have reconsidered the role of

lateral tears and reconstructions in rotatory instabilities and

often perform extra-articular reconstructions in association

with the intra-articular reconstructions [1, 25, 27]. The role

and effectiveness of a lateral extra-articular procedure

performed in association with ACL reconstruction has not

been defined [30]. While some authors have expressed

belief that postoperative stability cannot be improved by

any additional procedure [3], others have reported better

results when an extra-articular iliotibial band tenodesis was

performed in association with an intra-articular ACL

reconstruction, especially if a semitendinosus and gracilis

graft was used [15, 34]. In vitro analysis performed by

Engebretsen et al. [8] has shown that the extra-articular

plasty, when used in combination with intra-articular

reconstruction, reduces the stress to the graft by approxi-

mately 43%. Moreover, some biomechanical in vitro

studies [26, 28] demonstrate that the extra-articular

reconstruction reduces the internal rotation of the tibia with

less risk of pivoting. More recently, the role of the extra-

articular reconstruction in reducing the internal rotation of

476 Knee Surg Sports Traumatol Arthrosc (2011) 19:473–478

123

the tibia has also been demonstrated in vivo with computer-

assisted surgery [28].

A modified MacIntosh lateral tenodesis [26] was used to

treat severe chronic rotatory laxity (3? pivot-shift test) in 23

patients committed to professional sports activities; at fol-

low-up, all of these patients were graded as normal or nearly

normal, with and without evidence of degenerative changes

when compared to patients treated with an intra-articular

reconstruction alone. Moreover, considering as biome-

chanical reconstruction failure a 2? or 3? pivot-shift test

and/or a KT-1000 side-to-side difference of more than

5 mm, we observed 6 cases of failure (3 men and 3 women).

All of these 6 patients were operated without the extra-

articular tenodesis. The highly satisfactory results obtained

in this series show that, from a clinical point of view, a

combination of intra and extra-articular procedures for ACL

reconstruction is a valid option and seems to confirm the

role of the procedure to restore rotator stability of the knee

also at long-term follow-up, especially in severe rotatory

instabilities.

In the last few years, the use of an accelerated rehabil-

itation program after ACL reconstruction has become

widely accepted. However, it is well known that secure

tendon-to-bone healing requires at least 12 weeks. There-

fore, accelerated rehabilitation and the related micromotion

of the graft in the tunnels could compromise the bone-

tendon interface, resulting in poor biological fixation

[7, 33]. When hamstring grafts are used, even when strong

and stiff fixation devices are utilized, we believe that a

slower rehabilitation program such as the one employed in

the present study should be suggested. However, despite

the initial unaggressive regimen used in this series, almost

all patients, 77 of 92 (83.7%) could return to their

pre-operative sport level and activity within 6 months

postoperatively.

The limitation of this study is that there is no control

group. However, the strength is in reporting clinical,

functional and radiological results at a long-term follow-up

for a series of 100 consecutive patients operated by the

same senior surgeon.

An 8% loss to follow-up allows a representative

outcome evaluation. Clinical evaluation revealed good-

to-excellent subjective results at IKDC in 79/80 patients

(group A and B) with a stable knee joint and a side-to-side

difference at KT-1000 of less than 5 mm in 74/80 patients

(92.5%).

In agreement with previously published studies, we

found worst objective results at IKDC evaluation

(P = 0.01) and a trend toward worst arthrometric results

(n.s.) in women. However, the IKDC score revealed

excellent results (group A) in all women who underwent

extra-articular tenodesis.

Conclusion

In conclusion, we still consider the hamstrings an excellent

graft for ACL reconstruction. However, in light of the

findings shown in this paper, we introduced a new har-

vesting technique for the semitendinosus [13], preserving

as much of its distal insertion as possible, thus preventing

internal rotation strength deficit and extending indication

for the lateral tenodesis to the moderate rotator laxity

(pivot-shift 2?), especially in women.

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