Extract
Anterior cruciate ligament rupture is the most common knee ligament injury.
Of the grafts that are used for anterior cruciate ligament reconstruction,
bone-patellar tendon-bone is still the most common because of its initial
fixation stability and its ultimate tensile strength and elastic modulus,
which are superior to those of other graft sources. Hamstring tendon grafts
recently have demonstrated functional results equivalent to those of
bone-patellar tendon-bone grafts. While most recent studies have failed to
demonstrate significant differences between the two types of grafts, many
authors have reported on their strengths and
weaknesses1-12.
While there has been a trend toward better stability in association with
bone-patellar tendon-bone grafts, postoperative complications, including
anterior knee pain and patellofemoral problems, have been reported
frequently13-20.
Knee-extension deficits have been reported to occur more frequently in
association with bone-patellar tendon-bone grafts as compared with hamstring
tendon
grafts1,7.
Graft laxity and tunnel enlargement have been reported in association with
hamstring tendon grafts, and some authors have found persistent muscular
deficits in knee flexion and internal rotation strength after treatment with
hamstring tendon
grafts5,21.
Anterior cruciate ligament rupture is the most common knee ligament injury.
Of the grafts that are used for anterior cruciate ligament reconstruction,
bone-patellar tendon-bone is still the most common because of its initial
fixation stability and its ultimate tensile strength and elastic modulus,
which are superior to those of other graft sources. Hamstring tendon grafts
recently have demonstrated functional results equivalent to those of
bone-patellar tendon-bone grafts. While most recent studies have failed to
demonstrate significant differences between the two types of grafts, many
authors have reported on their strengths and
weaknesses1-12.
While there has been a trend toward better stability in association with
bone-patellar tendon-bone grafts, postoperative complications, including
anterior knee pain and patellofemoral problems, have been reported
frequently13-20.
Knee-extension deficits have been reported to occur more frequently in
association with bone-patellar tendon-bone grafts as compared with hamstring
tendon
grafts1,7.
Graft laxity and tunnel enlargement have been reported in association with
hamstring tendon grafts, and some authors have found persistent muscular
deficits in knee flexion and internal rotation strength after treatment with
hamstring tendon
grafts5,21.
In 2004, we reported the early results for a series of patients undergoing
anterior cruciate ligament reconstruction with use of a quadriceps tendon
autograft22. The
central quadriceps tendon-patellar bone autograft has been proposed as a
reasonable source of anterior cruciate ligament graft by some authors as it
offers adequate mechanical strength and easier rehabilitation, while some
postoperative complications can be
avoided23-28.
The anatomy and mechanical properties of the quadriceps tendon were well
described in a series of studies by Stäubli et
al.27,29-31.
The cross-sectional area of the quadriceps tendon was almost twice that of the
patellar tendon, the mean initial length of the quadriceps tendon was
approximately 20 mm longer than that of the patellar tendon, and ultimate
strains for the two types of grafts were equivalent. The ultimate tensile
stress value and Young's modulus of the quadriceps tendon were approximately
50% of those of the patellar tendon. The quadriceps tendon demonstrated an
equivalent ultimate load to failure, 1 mm more of ultimate displacement, and
70% stiffness when compared with the patellar tendon. Overall, these
mechanical properties are sufficient for substitution of the native anterior
cruciate ligament. In addition, the quadriceps tendon is composed of several
individual layers, which are readily separated to form two strands if the
whole layer is harvested. Of concern, however, is that the quadriceps tendon
is considered by many to be essential for quadriceps muscle strength and its
postoperative rehabilitation.
The purpose of the present study was to comprehensively evaluate anterior
cruciate ligament reconstruction with use of a quadriceps tendon autograft,
including the clinical outcome in terms of graft stability, the functional
results, donor-site morbidity along with its morphologic changes on magnetic
resonance imaging, and second-look arthroscopic findings with ultrastructural
evaluation of the graft.
Patients
From February 1999 to December 2004, 350 patients underwent anterior
cruciate ligament reconstruction with use of an autologous central quadriceps
tendon-patellar bone graft. The present study includes 247 patients who had
been followed for more than twenty-four months. All procedures were primary
reconstructions of the anterior cruciate ligament for the treatment of
symptomatic acute or chronic injuries with or without meniscal injury.
Eighty-two patients who were followed for less than two years, fifteen
patients who had inadequate records or who refused to take part in the study
and were lost to follow-up, and six patients who had had previous surgery or a
concomitant posterior cruciate or posterolateral corner reconstruction were
excluded from the study. Seven knees (2.8%) were revised and were considered
to have had a failure and were not otherwise considered in the overall study
results. Demographic data, concomitant injuries, and the mechanisms of injury
are described in Tables I and
II.
The study was approved by the institutional review board at Seoul National
University College of Medicine/Seoul National University Hospital, and all
patients who were included in the study gave informed consent to
participate.
Surgical Technique and Postoperative Course
All arthroscopic anterior cruciate ligament reconstructions were performed
with use of a central quadriceps tendon-patellar bone
autograft22.
Arthroscopic examinations were first performed to confirm ligament rupture,
and all meniscal resections or repairs were completed before the anterior
cruciate ligament reconstruction. The ipsilateral central quadriceps tendon
was harvested by excising a trapezoidal bone block (measuring 10 mm wide, 20
to 25 mm long, and 7 mm thick) from the base of the patella and a strip of
quadriceps tendon (measuring 10 mm wide, 6 to 8 mm thick, and 6 to 7 cm long)
in continuity with the patellar bone block with use of a 10-mm Graft Harvester
(Parasmillie; Linvatec, Largo, Florida) and Metzenbaum scissors. Superficial
layers of the cut surface of the tendon were closed transversely with number-1
Vicryl sutures. The bone defect was not grafted. The patellar bone block was
perforated, and two 2-0 PDS sutures were passed through it. The tendinous
portion of the graft was secured with two number-5 Ethibond sutures (Ethicon,
Somerville, New Jersey) with use of Krackow-type sutures, with an extension of
approximately 30 mm. While the graft was prepared on the back table, tibial
and femoral tunnels were created. For the tibial tunnel, a guide-pin was
inserted into the point halfway between the medial collateral ligament and the
tibial tubercle at an angle of 55° from the plane of the tibial plateau
with use of a tibial drill-guide (Acufex, Andover, Massachusetts) aimed at the
posterior half of the anterior cruciate ligament footprint. In the sagittal
plane, the angle of the drill-guide was set at 30° to 40°. A
10-mm-diameter tibial tunnel was drilled. A 7.0-mm offset femoral drill-guide
(Acufex) was located between the 10 and 11 o'clock positions for the right
knee, and a 10-mm femoral tunnel was drilled through the tibial tunnel. The
depth of the femoral tunnel was determined by the length of the bone block of
the harvested graft. Notch-plasty was performed to visualize the femoral
tunnel and to prevent graft impingement, if necessary. The graft was then
passed through the tunnels, and a metal interference screw (Linvatec),
measuring 7 × 25 mm in most cases, was used to fix the bone block on the
femoral side. The knee was then cycled fifteen to twenty times through a full
range of motion with the graft under manual tension, and the graft was
observed for impingement. If impingement occurred and the graft was felt to
stretch, a more extensive notchplasty was performed. The tendinous portion on
the tibial side was fixed with a bioabsorbable screw (BioScrew; Linvatec)
measuring 9 or 10 mm in diameter and 25 mm in length. It was augmented by
tying sutures over the bicortical screw, which was inserted 1 cm inferior to
the tibial tunnel halfway between the tibial tubercle and the superficial
medial collateral ligament toward the posterolateral corner of the tibia.
Continuous passive motion was started within three days and was continued
for one to two days while the patient was hospitalized. Full hyperextension
was obtained in one week, and full flexion was obtained in six weeks. Kinetic
exercises and weight-bearing were progressed as tolerated, and a
motion-controlled brace was worn for two weeks (set at 0° to 90°) and
then for an additional four weeks (set at 0° to full flexion). Full
activity, including strenuous sports, was permitted at six months
postoperatively when recovery of quadriceps muscle strength was confirmed.
Clinical Evaluations and Radiographic Assessments
Patients were seen and evaluated at six weeks, at three-month intervals
until twelve months (at three, six, nine, and twelve months), and at six-month
intervals after twelve months (at eighteen, twenty-four, thirty, and
thirty-six months) postoperatively. Range-of-motion testing, the Lachman test,
the anterior drawer test, and the pivot-shift test were performed. The
side-to-side difference in anterior translation between the injured knee and
the contralateral, normal knee was measured with use of a KT-1000 arthrometer
(MEDmetric, San Diego, California). Quadriceps muscle strength was assessed
with use of a Cybex II isokinetic testing device (Cybex, New York, NY). The
percentage of the mean peak torque at a velocity of 60°/s and 180°/s
in the involved limb as compared with the un-involved limb was calculated. The
modified Lysholm knee score and the International Knee Documentation Committee
(IKDC) score were calculated. Postoperative anterior knee pain was assessed
with use of the Shelbourne and Trumper
questionnaire20.
The congruence angle was checked on the Merchant view to identify patellar
subluxation, and the Insall-Salvati ratio was calculated to evaluate the
postoperative patellar height changes.
Magnetic Resonance Imaging: Graft and Donor-Site Change
Fifty-nine patients volunteered to undergo postoperative magnetic resonance
imaging scans. Thirty-three preoperative and ninety-eight postoperative scans
were available for review. The postoperative scans were grouped according to
the interval between the operation and the follow-up date. Thirty-six magnetic
resonance imaging studies were performed at three to six months
postoperatively, twenty-six were made at seven to twelve months, fourteen were
made at thirteen to eighteen months, seven were made at nineteen to
twenty-four months, eight were made at twenty-five to thirty months, and seven
were made at or after thirty-one months.
Magnetic resonance images were acquired with use of three imaging machines:
a 1.0-T Magnetom Expert (Siemens, Erlangen, Germany), a 1.5-T Genesis Signa
(GE, Milwaukee, Wisconsin), and a 1.5-T Magnetom Vision Plus (Siemens). With
use of a knee-dedicated coil, sagittal, coronal, and oblique axial images of
T1, T2-weighted spin-echo, and fat-saturated proton-density fast-spin-echo
sequences were acquired. The quadriceps femoris tendon donor area was scanned
in addition to the grafted tendon. The signal intensity of the donor site was
measured as follows. The region of interest, with a diameter of 4 mm
(corresponding to 67 pixels) was defined with use of viewing software (mview;
Infinitt, Seoul, Korea) on the Picture Archiving and Communication System
(Infinitt). The signal intensity of the donor site was measured at the
quadriceps tendon donor area, and the ratio of the intensity of the donor site
to that of the hamstring or the gastrocnemius muscle in the same image was
calculated (Fig. 1,
A). Measurements were made at 1 cm from the base
of the patella, which was arbitrarily determined to normalize measurements.
The thickness of the donor sites and enhancements was also measured
(Fig. 1, B). To assess
graft signal intensity, the intra-articular portion of the anterior cruciate
ligament graft between the femoral and tibial tunnels on the sagittal image
was divided into thirds (proximal, middle, and distal), the region of interest
was defined for each third, and the signal intensity was measured
(Fig.
2)32.
Second-Look Arthroscopy: Biopsy and Transmission Electron Microscopic
Evaluation
Thirty-seven patients from the original cohort underwent second-look
arthroscopy at a mean of twenty-one months (range, six to sixty-four months)
after anterior cruciate ligament reconstruction. A biopsy specimen measuring
approximately 1 × 1 × 1 mm in size was obtained from the middle
third of the reconstructed anterior cruciate ligament in each patient with use
of a basket punch (ACUFEX; Smith and Nephew, Andover, Massachusetts). For use
as controls at time zero, biopsy specimens from the quadriceps tendon graft
from five patients were obtained when the graft was harvested at the time of
anterior cruciate ligament reconstruction. The median age of the patients in
the experimental group was twenty-nine years (range, nineteen to forty-four
years), and the median age of the five patients in the control group was
thirty years (range, twenty to forty-four years). Specimens were immediately
fixed in 2% glutaraldehyde and 0.5% paraformaldehyde in 0.1-M cacodylate
buffer containing 10-mM CaCl2 at a pH of 7.4. They were rinsed at 4°C in
0.1-M cacodylate buffer containing 3-mM CaCl2 at a pH of 7.4, postfixed in 1%
osmium tetroxide for two hours, dehydrated in a series of graded ethanol
washes followed by a xylene wash, and embedded in EPON. Ultra-thin sections
(500 to 600 Å) were cut and contrasted with uranyl acetate followed by
lead citrate. Transversely cut sections were examined with use of a JEM-100CX
transmission electron microscope (JEOL, Tokyo, Japan). The fibril diameter was
measured on printed copies (×75,000), was grouped into one of five size
classes (0 to 30, 31 to 60, 61 to 90, 91 to 120, and >120 nm), and was
presented as the percentage of fibrils (the ratio of the number of fibrils in
each class to the total number of fibrils) and total per area (the sum per
area of fibrils in each class). Three printed copies were analyzed for each
patient sample with use of image-analyzing software (Image-Pro Plus v. 4.5;
Media Cybernetics, Bethesda, Maryland)
(Fig. 3).
Statistical Analysis
All magnetic resonance imaging measurements were performed in triplicate on
a single image, and the mean value of these three measurements was used to
calculate the mean for all images. The intraobserver and interobserver
reliabilities of the measurements of the magnetic resonance images and the
electron microscopic assessments were confirmed. Related data from the
preoperative and postoperative periods were compared with use of the Wilcoxon
signed-rank test, and independent interval data were compared with use of the
Mann-Whitney U test. Significant differences for the magnetic resonance
imaging data were determined by means of one-way analysis of variance with
post hoc tests. The level of significance was set at p = 0.05. The
percentage of fibrils and the total per area on the electron microscopic
pictures were analyzed with use of the chi-square test to reveal a difference
in the size-class distribution between the time-points.
Range of Motion, Clinical Evaluation and Instrumented Testing of the
Ligament, and Lysholm and IKDC Scores
The range of knee motion did not change postoperatively (mean, 137.3°
preoperatively compared with 137.5° postoperatively). Two hundred and
thirty-four patients (97.5%) had an extension deficit of <3°, and 235
patients (97.9%) had a lack of flexion of <5° at the time of the latest
follow-up. Two hundred and twenty-seven patients (94.6%) demonstrated grade-0
or 1 laxity on the anterior drawer test, the Lachman test, or the pivot-shift
test. KT-1000 arthrometric analysis demonstrated significant improvement in
side-to-side differences on manual maximum testing (p < 0.001), with a mean
(and standard deviation) of 2.4 ± 1.7 mm at the time of the latest
follow-up, at which time eleven knees showed laxity of >5 mm
(Table III). The mean modified
Lysholm score33
improved significantly from 71 to 90 at the time of the latest follow-up (p
< 0.001). Two hundred and twelve patients (88.3%) graded the knee as normal
or nearly normal, and 211 patients could participate in strenuous or moderate
activities postoperatively. Overall, 209 patients (87.0%) had either a grade-A
or a grade-B score on the IKDC form at the time of the latest follow-up.
Complications
Seven knees (2.9%) were revised and were considered to have had a failure
and were not otherwise included in the overall study results. Four knees were
revised because of a traumatic rupture, and three were revised because of
graft failure with symptomatic instability without a history of a distinct new
injury. In one patient, an undisplaced longitudinal patellar fracture occurred
five months after reconstruction as the result of a fall and direct impact
with the ground. The fracture was treated nonoperatively, and the patient had
no functional deficit at the time of the latest follow-up. Two intraoperative
un-displaced patellar fractures were treated with internal fixation with 4.0
cannulated screws. These fractures did not influence the postoperative
rehabilitation schedule. Arthrolysis was performed because of postoperative
stiffness in two knees.
Donor-Site Morbidity
Donor-site tenderness was assessed separately by means of palpation, and
moderate harvest-site tenderness was observed in one patient. The anterior
knee pain questionnaire revealed that >90% of the patients were able to
participate in most activities, including sports, work, stair-climbing, and
long periods of sitting and kneeling, without moderate or severe
patellofemoral pain (see Appendix). Peak extension torque, measured with a
Cybex II isokinetic testing device, was 68.3% and 77.2% of that on the
contralateral side at 60°/s and 180°/s, respectively, prior to
reconstruction. These values diminished to 58.6% and 64.7% at six months
postoperatively and recovered to 79.0% and 81.9% after one year, 81.8% and
88.4% after two years, and 85.1% and 91.2% after three years.
Congruence Angle, Insall-Salvati Ratio, and Donor-Site Changes on
Magnetic Resonance Imaging
At the time of the latest follow-up, the patellar position showed no
significant change from the preoperative position in terms of the congruence
angle (mean, —7.9° preoperatively as compared with —7.4°
at the time of the latest follow-up) or the Insall-Salvati ratio (mean, 1.0
both preoperatively and at the time of the latest follow-up). On magnetic
resonance imaging, the thickness of the quadriceps tendon donor site was
increased at three to six months after reconstruction and then decreased
slowly over time to converge close to the preoperative value
(Fig. 4, A).
Its thickness was significantly greater from three to twenty-four months (p
= 0.05). The signal intensity of the quadriceps tendon donor site was
increased significantly in comparison with that of the hamstring muscle on
proton-density and T1-weighted images at three to six months postoperatively
(p = 0.05) and then decreased (Fig. 4,
B). At three to six months, the signal intensity
on T2-weighted images was increased, but the difference was not significant.
At thirteen to twenty-four months, the signal intensity on T2-weighted images
was significantly lower than the preoperative values (p = 0.019).
Morphological changes were observed on serial magnetic resonance images
(Fig. 5). Images acquired after
the infusion of contrast media (n = 13) showed enhancement of the donor site
at six months, but this enhancement was absent during the late postoperative
period.
Magnetic Resonance Imaging Findings, Second-Look Arthroscopy, and
Collagen Fibril Population of the Reconstructed Anterior Cruciate Ligament
Graft
The signal intensity of the graft was shown to vary over time
(Fig. 6). No significant
difference was found between time-points or between the proximal, middle, and
distal portions of the graft. We could not identify a correlation between the
signal intensity of the graft and the time from surgery or anterior laxity as
measured with the KT-1000 arthrometer. On second-look arthroscopy, most of the
transplanted grafts demonstrated continuity with good synovial coverage
(Fig. 7). Evaluation revealed
that thirty-two grafts were taut, four were mildly lax, and one was lax. The
lax graft was rated as a failure and was revised. There was no correlation
between the tension in the graft and the length of time since the procedure,
but the tension seen at the time of arthroscopy was well correlated with the
result of the Lachman test (p = 0.001) and with anterior laxity as measured
with the KT-1000 device (p = 0.025).
All collagen biopsy specimens were found to have regularly oriented
collagen fibrils on transmission electron microscopy. The density and size
distribution of the fibrils varied. Twenty-eight (76%) of the thirty-seven
specimens showed a bimodal pattern of fibrils composed of small and
large-diameter fibrils (Fig. 8,
A). The remaining nine specimens (24%) were
composed of mostly small-diameter fibrils
(Fig. 8, B).
Image analysis revealed that the five control quadriceps tendon specimens
harvested at the time of anterior cruciate ligament reconstruction displayed a
heterogeneous distribution. Large-diameter fibrils (>90 nm) occupied 18.2%
of the total number of fibrils and 49.3% of the total fibril area. The
proportion of the number and the area of the large-diameter fibrils were
decreased at the time of follow-up, ranging from 11% to 27% for number and
from 30% to 48% for area (Fig.
9). The relative distribution of the fibril classes was not
different between time-points, and the average diameter of the collagen
fibrils did not correlate with anterior laxity as demonstrated with KT-1000
testing. Although nine specimens (24%) showed a unimodal pattern of
small-diameter fibrils and the fibrils in the three small-diameter classes (0
to 30, 31 to 60, and 61 to 90 nm) were dominant in most images, >11% of the
total fibrils belonged to the large-diameter classes and these large-diameter
fibrils occupied >30% of the total fibril area until sixty-four months.
The present study was conducted to evaluate the clinical and functional
results of reconstruction of the anterior cruciate ligament with use of a
quadriceps tendon autograft. The results regarding graft stability and
postoperative complications related to the donor site were encouraging.
Patellofemoral pain is one of the most frequent problems after anterior
cruciate ligament reconstruction. Mechanical disturbances such as a limited
range of motion, infrapatellar contracture, arthrofibrosis, and patellar
tendon shortening have been reported to cause morbidity, although the pain is
probably
multifactorial14-17,20,34,35.
With regard to anterior knee pain, the quadriceps tendon autograft showed
results comparable with those seen in association with anterior cruciate
ligament reconstructions involving the use of a hamstring tendon
autograft10,36,37.
The reduced pain was possibly due to minimal disturbance of the patellar
position and the infrapatellar fat pad. During the course of the present
study, we did not observe major compromise in, or any sign of mechanical
disturbance of, the extensor mechanism. Moderate donor-site irritation was
seen in only one patient.
The assessment of quadriceps muscle power showed a mean of 82% recovery at
two years and 85% recovery at three years. These results are not inferior to
the variable results of previous studies involving other
autografts4,34,
and there have been reports in the literature that have shown satisfactory
recovery of quadriceps muscle strength after anterior cruciate ligament
reconstruction with use of a quadriceps tendon
autograft23,38.
Some of our subjects had <80% recovery after one year, perhaps because of
the rehabilitation program or their activity level.
Numerous reports on the donor site assessing not only the secondary
symptoms but also the morphological changes following reconstruction with
bone-patellar tendon-bone or hamstring autografts are now
available10,39-46.
In the present study, digitized magnetic resonance images of the quadriceps
tendon donor sites demonstrated considerable morphological change. The
thickness of the quadriceps tendon donor site increased at three to six months
after surgery and then decreased. Its signal was also hyperintense between
three to six months postoperatively, and T2-weighted images showed a decrease
at thirteen to twenty-four months. These findings can be explained as the
proliferation of scar tissue in the donor defect followed by remodeling of the
scar into more mature fibrous tissue, which eventually becomes tendon-like in
structure.
A difference exists between patellar tendon donor sites and the quadriceps
tendon donor site as the superficial layers of the latter are closed
transversely, thereby forming a closed space for repair tissue to be organized
between the sutured layer anteriorly and the vastus intermedius posteriorly.
Even if the vastus intermedius layer is inadvertently harvested, water-tight
closure of the tendon donor site is still possible with additional suture of
the most posterior layer of the thick quadriceps tendon. This secure repair
and subsequent tissue regeneration may be why the patients had no complaints
in this area.
With regard to the graft, the principal finding of the electron microscopic
study was that 76% of quadriceps tendon grafts maintained their original
bimodal pattern, which consisted of larger and smaller-diameter fibrils for as
long as sixty-four months postoperatively. Although we could not identify an
association between the distribution pattern of the collagen fibrils and the
amount of anterior translation measured with the arthrometer or with the
magnetic resonance imaging signal, this finding may indicate the mechanical
superiority of the quadriceps tendon, which could be further elucidated
through biomechanical testing. Mature adult tendon or ligament has a bimodal
distribution of collagen fibrils, which is quite similar among various
anatomical
structures47, and
it has been assumed that large-diameter fibrils are responsible for their
high-tensile properties because of their high density of intermolecular
collagen
cross-links48,49.
Also, several studies have correlated the loss of larger fibrils with ligament
failure50,51.
Shino et al. reported that anterior cruciate allografts consisted
predominantly of small-diameter collagen fibers (30 to 80 nm), which resulted
in a unimodal pattern in the collagen fibril profile twelve months after
reconstruction52.
Autologous patellar tendon demonstrated a similar pattern of transformation in
one animal
study53.
One limitation of the present study was the lack of histologic evaluation
of the donor site and the graft. Another limitation was that serial magnetic
resonance scans were not acquired for the same patients at different
time-points.
In conclusion, anterior cruciate ligament reconstruction with a central
quadriceps tendon-bone autograft typically resulted in a stable and functional
knee with little morbidity. Quadriceps muscle recovery was encouraging, and a
magnetic resonance imaging study showed changes in signal intensity and
thickness at the donor site, indicating postoperative remodeling of the
quadriceps tendon. On electron microscopy, almost three-quarters of the grafts
showed a bimodal fibrillar pattern, which is similar to that of the native
anterior cruciate ligament. We believe that the autologous quadriceps
tendon-bone construct is an excellent option for anterior cruciate ligament
reconstruction.
A table presenting the questionnaire on anterior knee pain is available
with the electronic versions of this article, on our web site at
(go to
the article citation and click on "Supplementary Material") and on
our quarterly CD-ROM (call our subscription department, at 781-449-9780, to
order the CD-ROM). ?
Aglietti P, Buzzi R, Zaccherotti G, De
Biase P. Patellar tendon versus doubled semitendinosus and gracilis tendons
for anterior cruciate ligament reconstruction. Am J Sports Med.
1994;22:
211-8.22211
1994
[PubMed][CrossRef]
Aglietti P, Giron F, Buzzi R, Biddau F,
Sasso F. Anterior cruciate ligament reconstruction: bone-patellar tendon-bone
compared with double semitendinosus and gracilis tendon grafts. A prospective,
randomized clinical trial. J Bone Joint Surg Am.
2004;86:
2143-55.862143
2004
[PubMed]
Aune AK, Holm I, Risberg MA, Jensen HK,
Steen H. Four-strand hamstring tendon autograft compared with patellar
tendon-bone autograft for anterior cruciate ligament reconstruction. A
randomized study with two-year follow-up. Am J Sports Med.
2001;29:
722-8.29722
2001
[PubMed]
Beynnon BD, Johnson RJ, Fleming BC,
Kannus P, Kaplan M, Samani J, Renström P. Anterior cruciate ligament
replacement: comparison of bone-patellar tendon-bone grafts with two-strand
hamstring grafts. A prospective, randomized study. J Bone Joint Surg
Am. 2002;84:
1503-13.841503
2002
Eriksson K, Anderberg P, Hamberg P,
Löfgren AC, Bredenberg M, Westman I, Wredmark T. A comparison of
quadruple semitendinosus and patellar tendon grafts in reconstruction of the
anterior cruciate ligament. J Bone Joint Surg Br.
2001;83:
348-54.83348
2001
[PubMed][CrossRef]
Feller JA, Webster KE. A randomized
comparison of patellar tendon and hamstring tendon anterior cruciate ligament
reconstruction. Am J Sports Med.
2003;31:
564-73.31564
2003
[PubMed]
Freedman KB, D'Amato MJ, Nedeff DD, Kaz
A, Bach BR. Arthroscopic anterior cruciate ligament reconstruction: a
metaanalysis comparing patellar tendon and hamstring tendon autografts.
Am J Sports Med. 2003;31:
2-11.312
2003
[PubMed]
Jansson KA, Linko E, Sandelin J,
Harilainen A. A prospective randomized study of patellar versus hamstring
tendon autografts for anterior cruciate ligament reconstruction. Am J
Sports Med. 2003;31:
12-8.3112
2003
O'Neill DB. Arthroscopically assisted
reconstruction of the anterior cruciate ligament. A prospective randomized
analysis of three techniques. J Bone Joint Surg Am.
1996;78:
803-13.78803
1996
[PubMed]
Scranton PE, Bagenstose JE, Lantz BA,
Friedman MJ, Khalfayan EE, Auld MK. Quadruple hamstring anterior cruciate
ligament reconstruction: a multicenter study. Arthroscopy.
2002;18:
715-24.18715
2002
[PubMed][CrossRef]
Shaieb MD, Kan DM, Chang SK, Marumoto
JM, Richardson AB. A prospective randomized comparison of patellar tendon
versus semitendinosus and gracilis tendon autografts for anterior cruciate
ligament reconstruction. Am J Sports Med.
2002;30:
214-20.30214
2002
[PubMed]
Yunes M, Richmond JC, Engels EA,
Pinczewski LA. Patellar versus hamstring tendons in anterior cruciate ligament
reconstruction: a meta-analysis. Arthroscopy.
2001;17:
248-57.17248
2001
[PubMed][CrossRef]
Bonamo JJ, Krinick RM, Sporn AA. Rupture
of the patellar ligament after use of its central third for anterior cruciate
reconstruction. A report of two cases. J Bone Joint Surg Am.
1984;66:
1294-7.661294
1984
[PubMed]
Kartus J, Magnusson L, Stener S,
Brandsson S, Eriksson BI, Karlsson J. Complications following arthroscopic
anterior cruciate ligament reconstruction. A 2-5-year follow-up of 604
patients with special emphasis on anterior knee pain. Knee Surg Sports
Traumatol Arthrosc. 1999;7:
2-8.72
1999
[CrossRef]
Kartus J, Movin T, Karlsson J.
Donor-site morbidity and anterior knee problems after anterior cruciate
ligament reconstruction using autografts. Arthroscopy.
2001;17:
971-80.17971
2001
[PubMed][CrossRef]
Kartus J, Stener S, Lindahl S,
Engström B, Eriksson BI, Karlsson J. Factors affecting donor-site
morbidity after anterior cruciate ligament reconstruction using bone-patellar
tendon-bone autografts. Knee Surg Sports Traumatol Arthrosc.
1997;5:
222-8.5222
1997
[PubMed][CrossRef]
Kleipool AE, van Loon T, Marti RK. Pain
after use of the central third of the patellar tendon for cruciate ligament
reconstruction. 33 patients followed 2-3 years. Acta Orthop
Scand. 1994;65:
62-6.6562
1994
[CrossRef]
Mickelsen PL, Morgan SJ, Johnson WA,
Ferrari JD. Patellar tendon rupture 3 years after anterior cruciate ligament
reconstruction with a central one third bone-patellar tendon-bone graft.
Arthroscopy. 2001;17:
648-52.17648
2001
[PubMed][CrossRef]
Muellner T, Kaltenbrunner W, Nikolic A,
Mittlboeck M, Schabus R, Vécsei V. Shortening of the patellar tendon
after anterior cruciate ligament reconstruction. Arthroscopy.
1998;14:
592-6.14592
1998
[PubMed][CrossRef]
Shelbourne KD, Trumper RV. Preventing
anterior knee pain after anterior cruciate ligament reconstruction. Am
J Sports Med. 1997;25:
41-7.2541
1997
[CrossRef]
Nakamura N, Horibe S, Sasaki S,
Kitaguchi T, Tagami M, Mitsuoka T, Toritsuka Y, Hamada M, Shino K. Evaluation
of active knee flexion and hamstring strength after anterior cruciate ligament
reconstruction using hamstring tendons. Arthroscopy.
2002;18:
598-602.18598
2002
[PubMed][CrossRef]
Lee S, Seong SC, Jo H, Park YK, Lee MC.
Outcome of anterior cruciate ligament reconstruction using quadriceps tendon
autograft. Arthroscopy.
2004;20:
795-802.20795
2004
[PubMed]
Chen CH, Chen WJ, Shih CH. Arthroscopic
anterior cruciate ligament reconstruction with quadriceps tendon-patellar bone
autograft. J Trauma. 1999;
46: 678-82.46678
1999
[PubMed][CrossRef]
Fulkerson JP, Langeland R. An
alternative cruciate reconstruction graft: the central quadriceps tendon.
Arthroscopy. 1995;11:
252-4.11252
1995
[PubMed][CrossRef]
Harris NL, Smith DA, Lamoreaux L,
Purnell M. Central quadriceps tendon for anterior cruciate ligament
reconstruction. Part I: morphometric and biomechanical evaluation. Am J
Sports Med. 1997;25:
23-8.2523
1997
[CrossRef]
Stäubli HU. Arthroscopically
assisted ACL reconstruction using autologous quadriceps tendon. In: Jakob RP,
Stäubli HU, editors. The knee and the cruciate ligaments.
Berlin: Springer; 1992. p
443-51.443
1992
Stäubli HU, Jakob RP. Central
quadriceps tendon for anterior cruciate ligament reconstruction. Part I:
morphometric and biochemical evaluation. Am J Sports Med.
1997;25:
725-7.25725
1997
[PubMed]
Blauth W. Die zweizugelige Ersatzplastik
des vorderen Kreuzbandes aus der quadricepssehne. [2-strip substitution-plasty
of the anterior cruciate ligament with the quadriceps tendon].
Unfallheilkunde. 1984;87:
45-51. German.8745
1984
[PubMed]
Schatzmann L, Brunner P, Stäubli
HU. Effect of cyclic preconditioning on the tensile properties of human
quadriceps tendons and patellar ligaments. Knee Surg Sports Traumatol
Arthrosc. 1998;6 Suppl 1:
S56-61.6S56
1998
[CrossRef]
Stäubli HU, Bollmann C, Kreutz R,
Becker W, Rauschning W. Quantification of intact quadriceps tendon, quadriceps
tendon insertion, and suprapatellar fat pad: MR arthrography, anatomy, and
cryosections in the sagittal plane. AJR Am J Roentgenol.
1999;173:
691-8.173691
1999
[PubMed]
Stäubli HU, Schatzmann L, Brunner
P, Rincón L, Nolte LP. Quadriceps tendon and patellar ligament:
cryosectional anatomy and structural properties in young adults. Knee
Surg Sports Traumatol Arthrosc.
1996;4:
100-10.4100
1996
[CrossRef]
Howell SM, Clark JA, Farley TE. Serial
magnetic resonance study assessing the effects of impingement on the MR image
of the patellar tendon graft. Arthroscopy.
1992;8:
350-8.8350
1992
[PubMed][CrossRef]
Tegner Y, Lysholm J. Rating systems in
the evaluation of knee ligament injuries. Clin Orthop Relat
Res. 1985;198:
43-9.19843
1985
Rosenberg TD, Franklin JL, Baldwin GN,
Nelson KA. Extensor mechanism function after patellar tendon graft harvest for
anterior cruciate ligament reconstruction. Am J Sports Med.
1992;20:
519-6.20519
1992
[PubMed][CrossRef]
Spicer DD, Blagg SE, Unwin AJ, Allum RL.
Anterior knee symptoms after four-strand hamstring tendon anterior cruciate
ligament reconstruction. Knee Surg Sports Traumatol Arthrosc.
2000;8:
286-9.8286
2000
[PubMed][CrossRef]
Corry IS, Webb JM, Clingeleffer AJ,
Pinczewski LA. Arthroscopic reconstruction of the anterior cruciate ligament.
A comparison of patellar tendon autograft and four-strand hamstring tendon
autograft. Am J Sports Med.
1999;27:
444-54.27444
1999
[PubMed]
Feller JA, Webster KE, Gavin B. Early
post-operative morbidity following anterior cruciate ligament reconstruction:
patellar tendon versus hamstring graft. Knee Surg Sports Traumatol
Arthrosc. 2001;9:
260-6.9260
2001
[CrossRef]
Chen CH, Chen WJ, Shih CH. Arthroscopic
reconstruction of the posterior cruciate ligament: a comparison of quadriceps
tendon autograft and quadruple hamstring tendon graft.
Arthroscopy. 2002;18:
603-12.18603
2002
[PubMed][CrossRef]
Berg EE. Intrinsic healing of a patellar
tendon donor site defect after anterior cruciate ligament reconstruction.
Clin Orthop Relat Res.
1992;278:
160-3.278160
1992
[PubMed]
Coupens SD, Yates CK, Sheldon C, Ward C.
Magnetic resonance imaging evaluation of the patellar tendon after use of its
central one-third for anterior cruciate ligament reconstruction. Am J
Sports Med. 1992;20:
332-5.20332
1992
[CrossRef]
Kartus J, Movin T, Papadogiannakis N,
Christensen LR, Lindahl S, Karlsson J. A radiographic and histologic
evaluation of the patellar tendon after harvesting its central third.
Am J Sports Med. 2000;28:
218-26.28218
2000
[PubMed]
Liu SH, Hang DW, Gentili A, Finerman GA.
MRI and morphology of the insertion of the patellar tendon after graft
harvesting. J Bone Joint Surg Br. 1996;
78: 823-6.78823
1996
[PubMed]
Nixon RG, SeGall GK, Sax SL, Cain TE,
Tullos HS. Reconstitution of the patellar tendon donor site after graft
harvest. Clin Orthop Relat Res. 1995;
317: 162-71.317162
1995
[PubMed]
Eriksson K, Larsson H, Wredmark T,
Hamberg P. Semitendinosus tendon regeneration after harvesting for ACL
reconstruction. A prospective MRI study. Knee Surg Sports Traumatol
Arthrosc. 1999;7:
220-5. Erratum in: Knee Surg Sports Traumatol
Arthrosc. 2001;9:54-5.7220
1999
[CrossRef]
Papandrea P, Vulpiani MC, Ferretti A,
Conteduca F. Regeneration of the semi-tendinosus tendon harvested for anterior
cruciate ligament reconstruction. Evaluation using ultrasonography. Am
J Sports Med. 2000;28:
556-61.28556
2000
Rispoli DM, Sanders TG, Miller MD,
Morrison WB. Magnetic resonance imaging at different time periods following
hamstring harvest for anterior cruciate ligament reconstruction.
Arthroscopy. 2001;17:
2-8.172
2001
[PubMed][CrossRef]
Baek GH, Carlin GJ, Vogrin TM, Woo SL,
Harner CD. Quantitative analysis of collagen fibrils of human cruciate and
meniscofemoral ligaments. Clin Orthop Relat Res.
1998;357:
205-11.357205
1998
[PubMed][CrossRef]
Parry DA, Barnes GR, Craig AS. A
comparison of the size distribution of collagen fibrils in connective tissues
as a function of age and a possible relation between fibril size distribution
and mechanical properties. Proc R Soc Lond B Biol Sci.
1978;203:
305-21.203305
1978
[PubMed][CrossRef]
Shadwick RE. Elastic energy storage in
tendons: mechanical differences related to function and age. J Appl
Physiol. 1990;68:
1033-40.681033
1990
[CrossRef]
Józsa L, Bálint BJ,
Réffy A, Demel Z. Fine structural alterations of collagen fibers in
degenerative tendinopathy. Arch Orthop Trauma Surg.
1984; 103:
47-51.10347
1984
[PubMed][CrossRef]
Magnusson SP, Qvortrup K, Larsen JO,
Rosager S, Hanson P, Aagaard P, Krogsgaard M, Kjaer M. Collagen fibril size
and crimp morphology in ruptured and intact Achilles tendons. Matrix
Biol. 2002;21:
369-77.21369
2002
[CrossRef]
Shino K, Oakes BW, Horibe S, Nakata K,
Nakamura N. Collagen fibril populations in human anterior cruciate ligament
allografts. Electron microscopic analysis. Am J Sports Med.
1995;23:
203-9.23203
1995
[PubMed][CrossRef]
Moeller HD, Bosch U, Decker B. Collagen
fibril diameter distribution in patellar tendon autografts after posterior
cruciate ligament reconstruction in sheep: changes over time. J
Anat. 1995;187:
161-7.187161
1995