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The Results of Surgical Repair of Acute Tears
of the Posterior Cruciate Ligament
JOHN POURNARAS,
M.D., AND PANP. SYMEONIDES,
M.D.
In 20 patients, the torn posterior cruciate ligament
(PCL) was repaired without reinforcement within
two weeks after injury. Fourteen patients had a
midsubstance tear, and in six the ligament was
avulsed from the femur without bone. There were
11 isolated and nine combined injuries. The followup period ranged from two to 10.5 years. Postoperatively, all had posterior instability graded from
1 + to 2+. Nevertheless, the subjective results
were good in 15 patients, fair in five, and poor in
none. Posterior instability did not produce significant functional impairment of the knee for a considerable number of years. Suture alone cannot restore the PCL and is not strong enough to withstand the applied forces on the knee.
The significance of the posterior cruciate
ligament (PCL) in the stability of the knee
and the necessity for surgical repair of its
tears are still controversial. There are reports
in the literature based on clinical and biomechanic studies in which the PCL is considered
a prime stabilizer of the
Furthermore, it has been stated that posterior instability will often lead to the development of articular cartilage changes.*
On the contrary, Dandy and Pusey3 questioned the importance of the PCL for good
function of the knee. In addition, in experimental work in dogs it was found that sectioning the PCL produced fewer changes in
From the Orthopaedic Department, Aristotelian University of Thessaloniki, G. Papanikolaou Hospital, Thessaloniki, Greece.
Reprint requests to John Pournaras, M.D., Orthopaedic Department, Aristotelian University of Thessaloniki,
54006 Thessaloniki, Greece.
Received: July 3 I , 1989.
the joint, e.g.,meniscal tears, osteophyte formation, or articular cartilage changes, than
did sectioning of the anterior cruciate ligament (ACL)." Because there is a direct relationship between the amount of change and
the degree of instability, it was concluded that
in dogs, at least, the PCL was less important
than the ACL in the stability of the knee.
It should also be mentioned that in reported cases of PCL rupture, the subjective
and objective results after surgical repair are
not equally good. Thus in the series of Hughston et aL6 of 20 cases with acute tears of the
PCL, the subjective results were good in 18
(90%) and the objective results were good in
I3 (65%).Moore and Larson' also found that
of 18 surgically repaired cases of PCL tears
with or without dynamic reinforcement, 15
(83%)had residual instability; however, in 14
(77.7%)the functional result was excellent or
good. From these reports it is obvious that
there is a disparity between the presence of
postsurgical posterior instability and the
function of the knee. It is also assumed that
surgical treatment of acute tears of the PCL is
not always successful. The latter does not apply to the avulsion injuries from the tibia
with bone.
The purpose of this paper is to present the
results of surgical repair in 20 cases with
acute rupture of the PCL.
MATERIALS AND METHODS
Twenty patients with an acute PCL rupture
were surgically treated during the last 10.5 years.
In 14 patients, the ligament had a midsubstance
103
104
Pournaras and Syrneonides
tear and in six it was avulsed without bone from its
femoral attachment. Avulsion injuries of the ligament with a piece of bone from the tibia were excluded from this study.
Seventeen of the patients were men and three
were women, ranging in age from 18 to 41 years
(average, 26 years).
The causes of the knee injuries were traffic accidents in 12 (most involving a motorcycle), falls
from a height to the ground in five, and sports
injuries in three (long jump in two and skiing
in one).
It was difficult for the patients to describe precisely the exact position ofthe knee at the moment
of injury, particularly for those involved in motorcycle accidents. However, forcible posterior displacement of the tibia in a flexed knee with or
without rotation was the most common mechanism of injury. In one patient only, the rupture
was the result of a hyperextension injury of the
knee.
In 1 1 patients, the injury of the PCL was isolated. In four it was combined with a tear of the
medial collateral ligament, in three with a tear of
the lateral collateral ligament and the posterola-
Clinical Orthopaedics
and Related Research
teral corner, in one with rupture ofthe medial collateral ligament and ACL, and in another one with
injury to the ACL.
In all knees a positive posterior drawer test or
sag of the tibia of from 2 t to 3+ was present with
the knee in 90" flexion. This sag could also be
demonstrated roentgenographically (Figs. 1 and
2). A mild to moderate degree of effusion of the
knee existed in all patients. In the cases in which
the tear of the PCL was combined with a tear of
the medial or lateral structures, there was a positive abduction or adduction test in extension.
All patients were operated on within the first
two weeks after injury. The midsubstance tears
were repaired with an end-to-end suture using silk
No. 1 (Ethicon, Somerville, New Jersey). A technique similar to the Bunnel method of suturing
tendons was used, i.e., one suture was passed
through the proximal part and the other through
the distal portion of the torn ligament. The two
sutures were tightened together until good approximation is achieved. No other structures were used
to reinforce this suture.
In the avulsion injuries from the femur without
bone, two tunnels were opened from the medial
FIG. I A and 1 B. Preoperative lateral roentgenograms of (A) the normal left knee and (B) the right knee
with the PCL tear. The posterior displacement of the tibia (posterior sag) is evident.
Number 267
June. 1991
Acute PCL Tears
105
FIG.2A and 2B. Lateral roentgenograms from another patient with a PCL tear. (A) The posterior sag of
the tibia (right knee) is clearly shown compared to the (B) normal left knee.
side ofthe medial femoral condyle directed toward
the lateral side in the intercondylar notch at the
point where the PCL is normally attached. A No. I
silk stitch attached to the end of the avulsed ligament was passed through these tunnels and tightened.
In 12 cases, the posterior approach described by
ODonoghue" was used. Care was taken to restore
the posterior capsule, which was significantlytraumatized in three cases. In six patients, the suture of
the torn ligament was performed through the same
medial or lateral approach that was used for repairing the medial or lateral structures. In the remaining two cases in which the ligament was
avulsed from the femur, it was reattached through
an anteromedial approach.
At the end of the operation, a Steinmann pin
was inserted through the upper end ofthe tibia and
incorporated in an above-knee plaster-of-paris
cast applied with the knee in 20" flexion. The
Steinmann pin was used to prevent posterior displacement of the tibia in the plaster, reducing the
stress on the sutured ligament. The plaster was removed after six to eight weeks, following which the
rehabilitation program commenced.
RESULTS
The patients were followed for two to 10.5
years (average, five years). All patients re-
turned to their previous normal daily activities and were able t o participate in recreational sports. None of the operated patients
took part in competitive sports either before
or after surgical intervention. They had no
pain after their usual activities. No episodes
of locking were reported. Five patients complained of occasional mild swelling after prolonged activity. Two had a feeling of knee
instability. In both of these patients, there
was a combined tear of the ACL that had not
been repaired. The subjective results following the criteria of Hughston el aL6 could be
graded as good in I5 patients and fair in five.
No patient had a poor subjective result. Even
in the two patients with a feeling of instability, the result was evaluated as fair when the
other parameters were taken into consideration. Four of the six patients with avulsion
of the ligament from its femoral attachment
had good results.
Objectively, all 20 patients had a positive
posterior drawer sign of 1+ to 2+, which was
manifested with posterior sag of the tibia.
None had restriction of knee movement of
106
Pournaras and Symeonides
more than 10”-15”. In five patients, there
was a mild effusion of the knee. No medial or
lateral instability was detected in the patients
with repaired rupture of the medial or lateral
structures. Muscle power of the quadriceps
was restored in all patients after prolonged
physiotherapy. Slight crepitus was palpable
in two. In one patient who had an unrepaired
combined tear of the ACL, this crepitus was
present one year after the operation. If the
objective results in these patients are evaluated with the criteria put forth by Hughston
et a/.,6 taking particularly into consideration
posterior instability, there were 12 fair and
eight poor results. In no patient could the objective result be graded as good because in
this category the posterior drawer test should
be negative.
DISCUSSION
The number of patients diagnosed with
rupture of the PCL has significantly increased over the last 20 years. This is because
of the increased number of traffic accidents,
particularly those of motorcyclists, the increased participation of people in competitive or recreational sports, and the improved
knowledge concerning the diagnosis of posterior instability of the knee.
The mechanism of injury is not always
clearly described, particularly for patients involved in traffic accidents who cannot remember the exact position of the knee at the
moment of the accident. Trickey” proposed
three mechanisms that could produce a tear
ofthe PCL: (1) an anteroposterior forceat the
front of the flexed knee (only the PCL is
usually injured); (2) hyperextension of the
knee, that will produce a tear of the ACL as
well; and (3) a posteriorly directed rotatory
injury which will also produce a tear of the
collateral ligament or the posterior corners of
the capsule. The first and third of the abovementioned mechanisms were the most common in the patients described in this report.
The posterior drawer sign or posterior sag
of the tibia is often considered the most reli-
Clinical Orthopaedics
and Related Research
able sign in diagnosing tears of the PCL, either isolated or combined. Some investigators state that it is always positive in acute
tears of this ligament or in chronic posterior
i n ~ t a b i l i t y . ~ , ~In
, ~ ,1980,
’’
Hughston et a/.,6
believed that the posterior drawer sign was
not a reliable test for acute ruptures. They
found it positive in only 30% of their cases of
acute tear of the PCL, all associated with rupture of the medial or lateral collateral ligament. They considered a more reliable sign to
be the abduction or adduction test with the
knee in extension and the anterior drawer
sign with the tibia in internal rotation. In all
patients reported here there was a positive
posterior drawer sign of 2+ to 3+- with the
tibia in neutral position. In one half of the
patients, the posterior displacement decreased when the tibia was held in internal
rotation. Clancy et a/.’ attributes this to the
presence of Humphry’s or Wrisberg’s ligament. These ligaments are tightened when
the tibia is internally rotated, preventing posterior displacement of the tibia.
It is interesting to note that all these patients had a positive posterior drawer sign despite the repair of the PCL and the insertion
of a Steinmann pin in the upper tibia to prevent posterior displacement until the ligament was healed. It seems that sutures alone
are not strong enough to resist the forces applied on the repaired PCL, which ultimately
fails and cannot provide static stability.
It has been previously reported that patients with posterior instability after a repaired or unrepaired tear of the PCL retain
good function of the k r ~ e e .Even
~ . ~ Hughston
el a/.,6who strongly support the view that the
PCL is a main stabilizer, found that in their
seven patients with poor or fair objective results, the subjective result was good in six. In
six of the seven there was a positive drawer
sign or unreducible posterior subluxation
rated 1 + to 2+. In all patients of this report,
the subjective results were good or fair. On
the contrary, objectively, the results were evaluated fair or poor. It should be pointed out
again that none of these patients was partici-
Number 267
June, 1991
Acute PCL Tears
pating in competitive athletic activities.
From the aforementioned, one may conclude that a failed PCL repair does not lead to
significant functional impairment in everyday activities, probably because it produces
single-plane and not rotatory instability.
REFERENCES
1. Butler, D. L., Noyes, F. R., and Grood, E. S.: Liga-
2.
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5.
mentous restraints to anterior-posterior drawer in
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Joint Surg. 62A:259, 1980.
Clancy, W. G., Shelbourne, K. D., Zoellner, G. B.,
Keene, J. S., Reider, B., and Rosenberg, T. D.:
Treatment of knee joint instability secondary to rupture of the posterior cruciate ligament: Report of a
new procedure. J. Bone Joint Surg. 65A:310, 1983.
Dandy, D. J., and Pusey, R. J.: The long-term results
of unrepaired tears of the posterior cruciate ligament. J. Bone Joint Surg. 648:92, 1982.
Fowler, P. J.: The classification and early diagnosis
of knee joint instability. Clin. Orthop. 147:15, 1980.
Hughston, J. C., Andrews, J. R., Gross, M. J., and
Moschi. A,: Classification of knee ligament instabili-
107
ties. Part I: The medial compartment and cruciate
ligaments. J. Bone Joint Surg. 58A: 159, 1976.
6. Hughston, J . C., Bowden, J. A,, Andrews, J. A,, and
Nonvood, L. A,: Acute tears ofthe posterior cruciate
ligament: Results of operative treatment. J. Bone
Joint Surg. 62A:438, 1980.
7. Kennedy, J. C., Hawkins, R. J., Willis, R. B., and
Danylchuk, K. D.: Tension studies of human knee
ligaments: Yield point, ultimate failure, and disruption of the cruciate and tibia1 collateral ligaments. J.
Bone Joint Surg. 58A:350, 1976.
8. Marshall, T. L., and Rubin, R. M.: Knee ligament
injuries: A diagnostic and therapeutic approach.
Orthop. Clin. North Am. 8:641, 1977.
9. Moore, H. A., and Larson, R. L.: Posterior cruciate
ligament injuries: Results of early surgical repair.
Am. J. Sports Med. 8:68, 1980.
10. O’Donoghue, D. H.: Surgical treatment of injuries
to the knee. Clin. Orthop. 18: 1 1, 1960.
11. Pournaras, J., Symeonides, P. P., and Karkavelas,
G.: The significance of the posterior cruciate ligament in the stability of the knee: An experimental
study in dogs. J. Bone Joint Surg. 65B:204, 1983.
12. Trickey, E. L.: Injuries to the posterior cruciate ligament: Diagnosis and treatment of early injuries and
reconstruction of late instability. Clin. Orthop.
147:76, 1980.
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