Abstract
Background: The evaluation and management of knee dislocations
remain variable and controversial. The purpose of this study was to describe
our method of surgical treatment of knee dislocations with use of a
standardized protocol and to report the clinical results.
Methods: Forty-seven consecutive patients presented with an occult
(reduced) or grossly dislocated knee. Fourteen of these patients were not
included in this series because of confounding variables: four had an open
knee dislocation, five had vascular injury requiring repair, three were
treated with external fixation, and two had associated injury. The remaining
thirty-three patients underwent surgical treatment for the knee dislocation
with our standard approach. Anatomical repair and/or replacement was performed
with fresh-frozen allograft tissue. Thirty-one of the thirty-three patients
returned for subjective and objective evaluation with use of four different
knee rating scales at a minimum of twenty-four months after the operation.
Results: Nineteen of the thirty-one patients were treated acutely
(less than three weeks after the injury) and twelve, chronically. The mean
Lysholm score was 91 points for the acutely reconstructed knees and 80 points
for the chronically reconstructed knees. The Knee Outcome Survey Activities of
Daily Living scores averaged 91 points for the acutely reconstructed knees and
84 points for the chronically reconstructed knees. The Knee Outcome Survey
Sports Activity scores averaged 89 points for the acutely reconstructed knees
and 69 points for the chronically reconstructed knees. According to the Meyers
ratings, twenty-three patients had an excellent or good score and eight had a
fair or poor score. Sixteen of the nineteen acutely reconstructed knees and
seven of the twelve chronically reconstructed knees were given an excellent or
a good Meyers score. The average loss of extension was 1°, and the average
loss of flexion was 12°. There was no difference in the range of motion
between the acutely and chronically treated patients. Four acutely
reconstructed knees required manipulation because of loss of flexion. Laxity
tests demonstrated consistently improved stability in all patients, with more
predictable results in the acutely treated patients.
Conclusions: Surgical treatment of the knee dislocations in our
series provided satisfactory subjective and objective outcomes at two to six
years postoperatively. The patients who were treated acutely had higher
subjective scores and better objective restoration of knee stability than did
patients treated three weeks or more after the injury. Nearly all patients
were able to perform daily activities with few problems. However, the ability
of patients to return to high-demand sports and strenuous manual labor was
less predictable.
Level of Evidence: Therapeutic study, Level III-2
(retrospective cohort study). See Instructions to Authors for a complete
description of levels of evidence.
Traumatic dislocation of the knee involves damage to multiple soft-tissue
stabilizing structures. Although there have been reports of isolated injuries
of the anterior or posterior cruciate ligament in the setting of a
dislocation1-3,
most often both cruciate ligaments are completely disrupted. In addition to
cruciate ligament injury, knee dislocation usually results in injury to either
the medial or the lateral capsular structures, resulting in combined
instability patterns. Articular and meniscal cartilage injuries, associated
osseous fractwures, and injuries to the neurovascular structures often add
more complexity to the evaluation and management of these dislocations.
Historically, loss of motion, chronic instability, and poor functional results
have been common outcomes for patients who sustain these complex
injuries4-8.
Strategies for the management of knee dislocation have been varied and
controversial9-11.
Because immobilization has generally resulted in poor
outcomes6,12,
most experienced surgeons have preferred surgical
treatment5,7,8,13-18.
Surgical management remains controversial, especially with regard to timing,
which structures to repair and/or reconstruct, and graft selection. Many
experienced knee surgeons have advocated that all associated ligamentous,
capsular, and meniscal injuries be treated with anatomical restoration (with
repair and/or
replacement)11,15,16,18-22.
Their philosophy has been that addressing only a portion of the injury in
these severely injured and unstable knees will lead to residual
laxity11,20-23.
Generally speaking, primary repair of the cruciate ligaments has fallen out of
favor unless there is an osseous
avulsion11,20-22,24,25.
Anatomical replacement with allograft or autograft tissue is the technique
preferred by most
surgeons11,20-22.
With respect to the timing of surgery, recommendations have ranged from
immobilization followed by delayed
surgery20,24
to surgical treatment within three weeks after the
injury4,5,7,11,18,21,22.
Finally, recommendations for postoperative rehabilitation have ranged from an
immediate range of
motion11,21,22,24,25
to immobilization for three to six weeks
postoperatively8,20.
The controversy over the management of these complex injuries is in large
part due to inconsistent treatment protocols, small and poorly defined patient
populations, and a variety of surgical techniques. The purpose of this study
was to evaluate the clinical outcomes of surgical treatment of knee
dislocation with use of a standard treatment protocol that included surgical
treatment within three weeks when possible, addressing all injured ligaments,
and an early protected postoperative range of motion. Our hypothesis was that
good or excellent results can be achieved with use of this standardized
surgical approach and postoperative protocol and that surgical treatment
within the first three weeks leads to better clinical outcomes than does
treatment after three weeks.
Patients
Forty-seven consecutive patients with either obvious or occult (reduced)
traumatic knee dislocation were evaluated at the University of Pittsburgh
Medical Center between 1990 and 1995. Obvious knee dislocations were those
that required reduction. Occult knee dislocations spontaneously reduced and
were defined by the presence of injuries to both cruciate ligaments, as
previously described by
Schenck26 and
Wascher et
al.27.
We retrospectively reviewed the records of all patients with a closed knee
dislocation that had been treated with our standard protocol. Of the
forty-seven patients with a dislocation, fourteen were excluded because of
confounding variables that necessitated alteration of our standard protocol.
These patients included four with open dislocation, five with vascular injury
requiring emergent vascular surgery, three treated with external fixation, and
two with associated injury (severe closed head injury and contralateral
below-the-knee amputation) that affected their treatment. The remaining
thirty-three patients underwent standard preoperative evaluation, surgical
management, and postoperative rehabilitation.
Preoperative Evaluation
In addition to a detailed history and physical examination, the initial
evaluation included standard radiographs and magnetic resonance imaging
studies of all patients. We defined acute surgical treatment as that performed
within the first three weeks after the injury and chronic treatment as that
carried out any time
thereafter14. Of
the thirty-five patients who presented with an acute dislocation, thirty-two
were evaluated with arteriograms, and six of those studies were positive. Five
of the six patients underwent emergent vascular surgery and were not included
in this study. The sixth patient had an intimal tear of the popliteal artery
and was included in the study.
Patients with a chronic dislocation were referred to the senior author
(C.D.H.). They were seen in the office, where the medical history was obtained
and physical examination and imaging studies were performed. Patients with
major arthritic changes noted on 45° posteroanterior flexion
weight-bearing, lateral, or Merchant radiographs were excluded from the study.
In addition, patients with a varus thrust on examination and/or malalignment
on long-cassette radiographs were excluded, as they were managed
differently.
Surgical Management
Surgical management was based on preoperative data, findings of the
examination under anesthesia, and arthroscopic findings. After anesthesia was
induced, the patient was positioned supine on the operating table, and an
examination under anesthesia was performed with use of the contralateral knee
as the control. A sandbag and lateral post were positioned to hold the knee
and hip at 90° of flexion. This setup also enabled us to move the knee
through a full range of motion throughout the examination and operation. A
Foley catheter was inserted, and distal pulses were checked with Doppler
ultrasound. A tourniquet on the proximal part of the thigh was utilized for
all patients.
The grade of ligament injury was determined during the examination under
anesthesia. These data were critical to surgical management. All grades were
determined in comparison with that of the uninvolved knee. Grade-1+ laxity is
a 3 to 5-mm side-to-side difference; grade-2+, 6 to 10-mm; and grade-3+,
>10 mm. By definition, a partial ligament injury is categorized as grade 1+
or 2+ and a complete tear, as grade 3+. The anterior cruciate ligament was
examined at 30° of flexion. The posterior cruciate ligament was examined
at 90° of flexion with use of the medial tibial step-off as a guide. Varus
laxity and valgus laxity were evaluated at 0° and 30° of flexion.
Gross opening at 0° with varus or valgus stress is consistent with a
complete collateral (grade-3+) ligament injury.
After sterile preparation and draping, proposed incisions were marked and
the tourniquet was inflated. The cruciate ligaments were addressed first, with
the goal of completing the majority of the cruciate ligament surgery within
the first two hours so that the tourniquet could be released for the
collateral ligament surgery. Gravity flow was used instead of an arthroscopic
pump to minimize fluid extravasation into the leg. The thigh and calf were
palpated prior to and throughout the procedure. If increased pressure was
noted, the arthroscopic procedure was discontinued and the operation was
completed with use of an open technique.
In our standard treatment protocol, avulsed ligaments and tears of the
medial collateral ligament were directly repaired, whereas complete tears of
the cruciate and lateral collateral ligaments were reconstructed with
fresh-frozen allograft tissue (LifeNet, Virginia Beach, Virginia). Remaining
injuries to the posterolateral structures were addressed by direct repair
and/or allograft replacement. Peripheral meniscal tears and capsular avulsions
were directly repaired. Central or irreparable meniscal tears were
débrided to a stable rim, with preservation of as much of the meniscus
as possible.
Skin incisions were determined by the pattern of injury. Midline incisions
were not used because of the potential for skin slough over the patella and
the limited access that they provide to the collateral structures. In all
knees, either a medial or a lateral curvilinear incision, as described by
Hughston and
Jacobson28 and by
Müller13, was
utilized for exposure of the collateral and capsular structures.
For combined (anterior and posterior) cruciate injuries with an associated
posterolateral corner injury, we used a medially based incision for the
cruciate replacement and a lateral curvilinear incision centered over the
Gerdy tubercle and the lateral tibial condyle for the posterolateral corner
(Fig. 1). The incisions were
separated by at least a 10-cm skin bridge over the patella. For injuries of
the anterior cruciate, posterior cruciate, and medial collateral ligaments, we
began with arthroscopy-assisted preparation of the tunnels for the anterior
and posterior cruciate ligaments. The medial collateral ligament was then
repaired through a medial curvilinear incision
(Fig. 2).
After viewing the medial and lateral compartments to look for meniscal and
articular cartilage lesions, we began the cruciate ligament surgery by
identifying the tibial attachment of the anterior and posterior cruciate
ligaments arthroscopically. The details of anterior and posterior cruciate
ligament replacement have been described in previous
reports29-32.
The femoral tunnel for the posterior cruciate ligament was placed to reproduce
the anterolateral component of the native
ligament32,33.
The tibial tunnel for the posterior cruciate ligament was approximated with a
Kirschner wire with use of an arthroscopic posterior cruciate ligament guide
(Linvatec, Largo, Florida). An anterior cruciate ligament tibial tunnel guide
(Linvatec) was used to place a Kirschner wire through the central portion of
the anterior cruciate ligament footprint, with the wire exiting 2 to 3 cm
proximal to the posterior cruciate ligament guide wire on the medial tibial
cortex. Intraoperative radiographs were made to check the positions of the
guide wires prior to drilling (Fig. 1,
f). The tibial tunnel for the posterior cruciate ligament
was drilled 10 to 11 mm under direct arthroscopic control. The tibial tunnel
for the anterior cruciate ligament was then drilled 10 to 11 mm. The femoral
tunnel for the posterior cruciate ligament was drilled with an outside-in
technique, through a 3-cm medial parapatellar
incision32. The
femoral tunnel for the anterior cruciate ligament was drilled with use of an
endoscopic
technique30. On a
separate table, fresh-frozen irradiated allografts were prepared after thawing
for twenty minutes. A 10 to 11-mm Achilles tendon graft was prepared for the
posterior cruciate ligament, and a 10 to 11-mm patellar tendon graft was
prepared for the anterior cruciate ligament. The Achilles tendon (i.e., the
posterior cruciate replacement) was passed from the femur to the tibia, and
the calcaneal bone plug was secured in the femoral tunnel with use of a 7 or
9-mm interference screw (Linvatec) at the femur. The patellar tendon graft
(the anterior cruciate replacement) was passed from the tibia to the femur and
secured on the femoral side with a 7 × 25-mm interference screw. The
tibial sides of both grafts were left free, and the collateral ligaments were
then addressed. At this point, the tourniquet was deflated, the peripheral
pulses were checked by palpation or Doppler ultrasound, and the collateral
ligament surgery was performed.
Injuries of the Anterior and Posterior Cruciate Ligaments and
Posterolateral Corner (Nine Knees)
For combined injuries of the anterior and posterior cruciate ligaments and
posterolateral corner, a 12 to 18-cm lateral curvilinear incision was centered
over the lateral epicondyle (Fig. 1,
e)13,28.
The course of the peroneal nerve around the fibular neck was identified, but
the nerve was not dissected unless peroneal nerve injury had been documented
preoperatively. When such an injury had been documented, the extent of the
damage was noted, and we released the nerve as it passed around the fibular
neck in three patients.
Each of the structures of the posterolateral corner was then systematically
evaluated. Lateral repairs and replacements were performed with the knee in
30° of flexion. Peripheral tears of the lateral meniscus were repaired
with use of nonabsorbable sutures, and capsular avulsions were repaired with
suture anchors. Osseous avulsion of the lateral collateral ligament or the
popliteus was directly repaired. More commonly, the injury of the lateral
collateral ligament was a midsubstance lesion requiring replacement, which was
done with an Achilles tendon allograft. A 7 to 8-mm bone plug was placed into
the fibular head and was secured with a metal interference screw. The
allograft was secured to the lateral femoral epicondyle with suture anchors,
and the native lateral collateral ligament was then repaired to the graft.
If there was increased posterolateral rotation on examination with the
patient under anesthesia, then the popliteus and its various attachments were
addressed. Great care was taken to identify the location of the injury (femur,
midsubstance, or tibia). If a femoral avulsion of the popliteus tendon was
noted, direct repair was performed. If a midsubstance injury had occurred,
reconstruction was performed with a hamstring tendon autograft in conjunction
with a primary repair. The reconstruction is designed to reproduce the
popliteal fibular
ligament34. A 6 to
7-mm tunnel was created in the proximal part of the fibula. The hamstring
graft was doubled over and taken through the fibular head tunnel. The graft
was then passed underneath the lateral collateral ligament and was placed into
a closed-end tunnel (7 mm in diameter) at the femoral attachment of the
popliteus tendon. The femoral attachment was then tied over a plastic button
on the medial femoral cortex. The final fixation of the lateral structures was
performed with the knee flexed to 30°. The popliteofibular ligament was
secured with a bioabsorbable screw in the fibular head. If the surgery
addressed both the lateral collateral ligament and the popliteofibular
ligament, the lateral collateral ligament was reconstructed and was secured
into a tunnel in the proximal part of the fibula as described above. The
popliteofibular graft was secured proximally, as described; passed deep to the
lateral collateral ligament graft; and brought from posterior to anterior
through a soft-tissue tunnel created at the biceps tendon insertion.
During this stage of the surgery, a bolster of sterile towels or drapes was
placed behind the tibia to maintain reduction. After the replacement or repair
of the collateral ligaments was completed, the knee was flexed to 90° and
the medial tibial step-off was palpated to reproduce the anatomy of the
uninvolved knee (usually 1 cm). The graft used for replacement of the
posterior cruciate ligament was tensioned and was fixed to the tibia with a
soft-tissue washer and screw (Linvatec). The knee was brought into full
extension, and the tibial side of the anterior cruciate ligament graft was
secured with a 7 × 25-mm interference screw (Linvatec)
(Fig. 1, g). Finally,
the incisions were irrigated and hemostasis was obtained. A drain was not
utilized. The knee was braced in full extension to minimize posteriorly
directed forces on the tibia from gravity and the hamstring muscles.
Injuries of the Anterior Cruciate, Posterior Cruciate, and Medial
Collateral Ligaments (Fifteen Knees)
For combined injuries of the anterior cruciate, posterior cruciate, and
medial collateral ligaments in which the medial collateral ligament injury was
grade 3+ with valgus stress in full extension, combined cruciate ligament
surgery with repair of the medial collateral ligament was performed. If the
knee did not exhibit a grade-3+ injury of the medial collateral ligament in
full extension, we did not repair the medial side and addressed only the
cruciate ligaments. (Four grade-2+ injuries of the medial collateral ligament
were not repaired.) After arthroscopic evaluation, tunnels were placed for the
cruciate ligaments prior to the medial-side repair. For repairs of the medial
collateral ligament, a single medial curvilinear incision was made beginning
at the level of the vastus medialis and was continued over the medial femoral
epicondyle to the anteromedial aspect of the tibia
(Fig. 2, f). This
allowed exposure of the medial collateral ligament and medial joint line.
Repair was performed with a series of nonabsorbable sutures and suture
anchors. Avulsions of the medial collateral ligament were reattached with
suture anchors, whereas midsubstance tears were primarily repaired with
nonabsorbable sutures. Access to the intercondylar notch was easily obtained
through the same incision. The anterior and posterior cruciate ligaments were
assessed and were replaced with use of arthroscopically assisted techniques
without fluid. In the three chronically injured knees with an injury of the
medial collateral ligament, the area of the injury (tibia, midsubstance, or
femur) was identified, and repair or reconstruction was focused in this area.
The magnetic resonance imaging and arthroscopic examination were extremely
helpful in identifying the location of the injury of the medial collateral
ligament. If the meniscus separated from the femur, we identified a
femoralside injury, and if it separated from the tibia, we diagnosed a
tibial-side injury. If reconstruction was needed in addition to the repair, a
semitendinosus autograft or an Achilles tendon allograft was placed
anatomically in the femoral and tibial attachments. The repair or replacement
was performed with the knee in 30° of flexion. The knee was flexed and
extended during the operation to ensure that the repair or replacement did not
overconstrain knee motion, which would lead to either stiffness or,
eventually, to residual laxity. The cruciate ligaments were then fixed on the
tibial side, and the knee was braced in full extension.
In general, the patients were observed overnight in the hospital and
discharged home on the following day. Prophylaxis against deep venous
thrombosis was given to high-risk patients.
Rehabilitation
A previously described postoperative program for knees with multiple
ligament injuries was utilized (Fig.
3)35.
To protect the healing structures, the limb was placed in a postoperative
brace that was locked in full extension for the first four weeks. Immediately
after surgery, emphasis was placed on restoring full passive extension
symmetrical to that of the uninvolved knee and restoring quadriceps function
so that the patient could perform a straight-leg raise without a quadriceps
lag. The exception to this was that passive knee extension was restricted to
zero and hyperextension was avoided for those who had had a repair or
replacement of the posterolateral corner. Exercises immediately after surgery
included passive knee extension and isometric quadriceps exercises with the
knee in full extension. Electrical stimulation that was sufficient to produce
a strong quadriceps contraction and/or electromyographic biofeedback was used
as necessary to enhance quadriceps function.
Passive flexion exercises, with use of an anteriorly directed force on the
proximal part of the tibia, were initiated two weeks after surgery. Active
contraction of the hamstrings to flex the knee was avoided for the first six
weeks, and motion during this period was limited to 90° of flexion. After
six weeks, passive and active-assisted range-of-motion and/or stretching
exercises were initiated to increase knee flexion. Use of the rehabilitation
brace was discontinued after six weeks if 90° to 100° of knee flexion
had been achieved. Knee flexion symmetrical to that of the uninvolved knee was
expected within twelve weeks. If the patient had <90° of flexion after
eight to twelve weeks, manipulation was performed with the patient under
anesthesia.
Quadriceps exercises were progressed to include limited-arc open-chain
knee-extension exercises in the midrange from 75° to 60° of flexion,
which corresponds to the quadriceps-neutral
angle36, as
tolerated after four weeks. Open-chain hamstring exercises were avoided for at
least three months. Closed-chain exercises were initiated four to six weeks
after surgery. Exercises that impart a valgus stress on the knee (i.e., hip
adduction exercises) were avoided for patients who had had a repair or
replacement of the medial collateral ligament, and exercises that impart a
varus stress on the knee (i.e., hip abduction exercises) were avoided for
those who had had a repair or replacement of the lateral collateral ligament
or posterolateral corner.
Immediately after surgery, the patient was limited to partial
weight-bearing with the brace locked in full extension. After four to six
weeks, the brace was unlocked for controlled gait training, and the patient
progressed to weight-bearing as tolerated. Use of crutches was discontinued
six to eight weeks after surgery, when the patient had minimal swelling in the
knee, full active and passive knee extension, and 100° of knee flexion and
was able to walk without a bent-knee gait. Once the patient was fully
weight-bearing, balance and proprioception exercises were initiated, beginning
with standing on the involved limb on a stable surface with the eyes open.
Balance and proprioception exercises were gradually progressed to include the
use of unstable surfaces such as foam mats and uniaxial and multiaxial balance
boards. Patients who performed sedentary work usually returned to work within
two weeks, but those who performed strenuous manual work did not return to
work until six to nine months. Individuals were allowed to return to
low-impact aerobic activities, such as walking, swimming, and bicycling, eight
to twelve weeks after surgery. They were allowed to run at six months provided
that they had at least 80% quadriceps strength compared with that of the
uninvolved knee. Return to sports activities requiring sudden changes in
direction and pivoting was delayed for nine to twelve months.
Follow-up Evaluation
Thirty-one of the thirty-three patients were evaluated more than two years
following surgery (see Appendix). Clinical evaluation included completion of a
series of self-administered questionnaires that allowed calculation of the
Lysholm, Meyers, and Knee Outcome Survey scores. Meyers functional scores have
been reported specifically for patients with knee dislocation and have been
utilized in studies by several
authors4,7,18,22,27.
The ratings were determined as proposed by Meyers and
Harvey18 and Meyers
et al.4. An
excellent rating indicates symptom-free return to work or to the preinjury
level of activity with a stable knee. A good rating indicates slight pain and
instability that does not preclude the patient's return to the preinjury
occupation or activity level. A fair rating indicates difficulty with stairs
or running causing the patient to avoid those activities. A poor rating
indicates marked limitation of activities of daily living or an inability to
work because of marked pain or instability.
The Knee Outcome Survey was developed at the University of Pittsburgh as a
patient-reported measure of symptoms and functional limitations for patients
with a variety of knee disorders, including ligamentous and meniscal
injuries37. The
Knee Outcome Survey consists of two scales: the Activities of Daily Living
Scale and the Sports Activity Scale. The Activities of Daily Living Scale
measures symptoms and functional limitations during activities of daily
living. The score ranges from 0 to 100 points, with 100 points indicating an
absence of symptoms and functional limitations during activities of daily
living. The Activities of Daily Living Scale has been shown to be a reliable,
valid, and responsive measure of symptoms and functional limitations during
activities of daily living in individuals with a variety of knee
injuries37. The
Sports Activity Scale measures symptoms and functional limitations experienced
during sports activities. The Sports Activity Scale score ranges from 0 to 100
points, with 100 points representing the absence of symptoms and functional
limitations during sports
activities38. The
scores on the Sports Activity Scale in our study are noteworthy since the
majority of our patients sustained the dislocation during sports activity.
All patients underwent a physical examination that included evaluation of
the range of motion and stability. The range of motion of both knees was
measured with use of a standard goniometric technique, and the loss of flexion
and extension relative to the uninvolved side was calculated. Stability was
determined manually and with the KT-1000 arthrometer (MEDmetric, San Diego,
California). The examination with the KT-1000 arthrometer was performed with
the knee at the quadriceps-neutral angle to determine corrected anterior and
posterior
translation36,39.
A thorough manual examination of the ligaments was performed by one of the
authors, and the results were graded according to the guidelines of the
International Knee Documentation Committee
(IKDC)40. When the
Lachman and anterior and posterior drawer tests were performed, care was taken
to ensure a normal tibiofemoral step-off prior to application of stress to the
tibia. Varus and valgus stability were determined at 30° of knee flexion.
The final overall IKDC rating was calculated according to the guidelines
described by Hefti et
al.40. The overall
final IKDC rating is based on group ratings for function, symptoms, range of
motion, and laxity. Each group rating is based on the two or more items that
are rated as normal, nearly normal, abnormal, or severely abnormal. The worst
rating for any item within a group determines the group rating, and the worst
group rating determines the overall final rating. Thus, the worst rating for
any particular item determines the overall final rating.
Data Analysis
Descriptive statistics, including means and standard deviations for
continuous variables and frequency counts for nominal and ordinal level
variables, were calculated. Independent t tests were performed for continuous
variables and chisquare tests were performed for nominal and ordinal level
variables to determine the significance of differences between patients
treated with acute replacement (less than three weeks after the injury) and
those treated with chronic replacement (more than three weeks after the
injury).
Thirty-one of thirty-three patients were available for evaluation at a mean
of forty-four months (range, two to six years) following surgery (see
Appendix). The mean age of these patients at the time of surgery was 28.4
years (range, sixteen to fifty-one years). Seventeen patients were injured
during sports activity; four, in an automobile accident; four, in a motorcycle
accident; four, in a work-related accident; and two, in a fall. Nineteen
patients underwent surgery less than three weeks (average, twelve days; range,
five to twenty-one days) after the injury. Twelve patients underwent surgery
more than three weeks (average, 6.5 months; range, five weeks to twenty-two
months) after the injury.
Injury patterns were variable and were determined by magnetic resonance
imaging, examination with the patient under anesthesia, and arthroscopy.
Fifteen of the nineteen patients with an acute injury underwent replacement of
both the anterior and the posterior cruciate ligament with fresh-frozen
allografts. One patient had a grade-2+ injury of the anterior cruciate
ligament that was not reconstructed, and two patients (Cases 10 and 18; see
Appendix) had a grade-2+ injury of the posterior cruciate ligament that was
not reconstructed. The other cruciate ligament was replaced in all three
patients. One patient had a peel-off injury of the posterior cruciate ligament
that was repaired primarily as well an injury of the anterior cruciate
ligament that was reconstructed with an allograft.
Of the nineteen patients who underwent acute treatment, ten had combined
injuries of the anterior cruciate, posterior cruciate, and medial collateral
ligaments with no lateral injury. Eight of those ten patients had repair of a
grade-3+ injury of the medial collateral ligament, and two did not undergo
repair of a grade-2+ injury. Seven of the nineteen patients had injuries of
the anterior cruciate ligament, posterior cruciate ligament, and
posterolateral corner. Five of the seven underwent allograft reconstruction of
the lateral collateral ligament with repair of posterolateral corner
structures. One patient had repair of an avulsion injury that included the
lateral collateral ligament and the biceps femoris insertion onto the fibular
head. One patient had an intact lateral collateral ligament and posterolateral
corner, but the anterolateral capsule and iliotibial band were avulsed and
were repaired. The remaining two acutely treated patients had sustained a
low-velocity knee dislocation. One of these patients had grade-3+ injuries of
the anterior and posterior cruciate ligaments but only grade-1+ injuries of
the medial collateral and lateral collateral ligaments. The other patient
sustained grade-3+ injuries of the anterior and posterior cruciate ligaments
and the medial collateral ligament with a grade-1+ injury of the
posterolateral corner that did not require surgical treatment.
The laxity patterns in the patients undergoing delayed surgery were
determined with intraoperative physical examination at the time of ligament
replacement. Eleven of the twelve patients with a chronic injury underwent
fresh-frozen allograft replacement of the anterior and posterior cruciate
ligaments. One seventeen-year-old patient underwent a primary repair of an
avulsion injury of the anterior cruciate ligament and an allograft replacement
of the posterior cruciate ligament one month after injury. Five patients who
underwent chronic treatment had injuries of the anterior cruciate, posterior
cruciate, and medial collateral ligaments. Three of the five patients had
grade-3+ laxity of the medial collateral ligament requiring repair. Two of the
five had grade-2+ laxity of the medial collateral ligament, and the anterior
and posterior cruciate ligaments were replaced without repair of the medial
collateral ligament. Two patients who underwent chronic treatment had grade-3+
injuries of the anterior and posterior cruciate ligament and laxity of the
posterolateral corner. The lateral collateral ligament was reconstructed with
fresh-frozen allograft in each of these patients. Five chronically treated
patients had isolated laxity of the anterior and posterior cruciate ligaments
without substantial varus or valgus laxity; no medial or lateral surgery was
performed in these patients.
Four patients had an injury of the common peroneal nerve. Three of these
injuries were transient, and one was permanent. One of the patients with
transient symptoms had paresthesias over the dorsum of the foot without motor
weakness on examination. The subjective paresthesias decreased over the ten
days prior to surgery. Since the symptoms were decreasing and the patient only
had minor varus laxity on examination under anesthesia, a lateral approach was
not thought to be necessary and the nerve was not explored. In the other three
patients, the nerve was identified and released as it passed the fibula. Two
patients with transient symptoms had decreased sensation over the dorsum of
the foot with weak ankle and toe dorsiflexion. Intraoperatively, both patients
were noted to have focal hemorrhage and swelling of the nerve. Gradual return
to full motor and sensory function occurred over approximately two months
postoperatively. The only patient who had a complete nerve deficit had had a
complete motor and sensory deficit at the time of presentation (Case 11; see
Appendix). This patient had an osseous avulsion of both the lateral collateral
ligament and the biceps femoris from the fibular head. The nerve was in
continuity, although gross swelling and hemorrhage were present over several
centimeters surrounding the proximal part of the fibula. The patient never
regained function and underwent a tendon transfer approximately nine months
following knee surgery.
Clinical Results
Clinical results were determined with an extensive questionnaire and
physical examination (see Appendix). The mean Lysholm score (and standard
deviation) was 87 ± 12.7 points (range, 50 to 100 points) for the
series as a whole, 91 ± 7.0 points (range, 72 to 100 points) for the
nineteen patients who underwent acute surgery, and 80 ± 16.9 points
(range, 50 to 100 points) for the twelve patients who underwent surgery more
than three weeks after injury. This difference between the acute and chronic
groups approached significance (two-tailed significance, p = 0.07, assuming
unequal variances).
The average Knee Outcome Survey Activities of Daily Living score for all
patients was 89 points (range, 64 to 99 points) in the series as a whole. The
score averaged 91 ± 6.4 points (range, 73 to 99 points) for the acutely
treated patients and 84 ± 11.8 points (range, 64 to 99 points) for the
patients who underwent chronic treatment. This difference approached
significance (two-tailed significance, p = 0.07, assuming unequal variances).
The average score on the Sports Activities Scale was 82 points (range, 0 to
100 points) in the entire series. The patients in the acute group had an
average score of 89 ± 10.3 points (range, 60 to 100 points), and those
in the chronic group had an average score of 69 ± 27.9 points (range, 0
to 100 points). This difference was significant (two tailed significance, p =
0.04, assuming unequal variances).
There were ten excellent, thirteen good, five fair, and three poor results
according to the Meyers functional rating. Of the nineteen patients in the
acute group, sixteen received an excellent or good rating and three received a
fair rating. Of the twelve patients in the chronic group, seven received an
excellent or good rating, two received a fair rating, and three received a
poor rating. The difference in the Meyers ratings between the acute and
chronic groups approached significance (p = 0.14).
All patients underwent a follow-up physical examination to determine the
range of motion and ligamentous stability (see Appendix). The total arc of
motion was similar between those who had undergone acute treatment (mean,
128° ± 10°; range, 115° to 145°) and those who had
undergone chronic treatment (mean, 129° ± 15°; range, 104°
to 144°). Flexion loss was calculated by subtracting the flexion of the
involved knee from that of the uninvolved knee, whereas extension loss was the
difference from anatomic zero as dictated by the 1993 IKDC
guidelines40. The
average extension loss was 1° ± 2° (range, 0° to 5°).
The thirteen patients with a slight flexion contracture had an average loss of
extension of 3°, and only one patient had a flexion contracture of
>5°. This patient had a 9° flexion contracture for the injured
knee; however, the patient also had an idiopathic 10° flexion contracture
of the contralateral, "normal" knee. Flexion loss was more
pronounced, with an average loss of 12° ± 9° (range, 0° to
33°). Fourteen patients lost between 5° and 15° of flexion, five
patients lost between 16° and 25° of flexion, and three patients lost
>25° of flexion. The patients in the acute group had an average loss of
13° ± 8° (range, 0° to 33°), and the patients in the
chronic group had an average loss of 10° ± 9° (range, 0° to
32°). The difference in the range of motion between the patients who
underwent acute treatment and those who underwent chronic reconstruction was
not significant.
On examination of the knee, all patients had a firm end point during the
Lachman test. Fifteen patients had a negative result of the Lachman test (0 to
2 mm of increased anterior tibial translation), and sixteen had 1+ laxity (3
to 5 mm of increased anterior tibial translation). All patients also had a
firm end point on the posterior drawer test. Twenty-two patients had 1+ laxity
(3 to 5 mm of increased posterior tibial translation), and nine patients had
2+ laxity (6 to 10 mm of increased posterior tibial translation). No patient
had a grade-3+ posterior drawer. Only three of the patients in the acute group
had 2+ laxity on posterior drawer testing, whereas six in the chronic group
had 2+ laxity. This difference was significant (two-sided p = 0.04).
Varus stress testing at 30° revealed 1+ laxity (3 to 5 mm of increased
laxity compared with that of the uninvolved knee) in nine patients and 2+
laxity (6 to 10 mm of increased laxity) in two patients. All other patients
had <3 mm of increased laxity. Varus laxity was 2+ in two patients who had
undergone replacement of the lateral collateral ligament.
Valgus stress testing at 30° revealed 1+ laxity (3 to 5-mm increase
compared with that of the uninvolved knee) in five patients and 2+ laxity (6
to 10-mm increase) in four patients. All other patients had <3 mm of
increased laxity compared with that of the uninvolved knee. Only one acutely
treated patient had 2+ laxity. At the time of examination under anesthesia,
this patient had had only mild valgus instability and the medial collateral
ligament was treated nonoperatively. The other three patients with 2+ valgus
laxity at the time followup had been treated chronically. Two of these three
had undergone repair of the medial collateral ligament because of grade-3+
laxity; one was treated five weeks after the injury and the other was treated
seven months after the injury. The remaining patient with chronic 2+ valgus
laxity had not had a repair of the medial collateral ligament.
KT-1000 data were obtained for twenty-five of the thirty-one patients and
demonstrated a mean corrected side-to-side difference in anterior translation
of 0.1 mm (range, —4 to 2.5 mm) and a mean corrected side-to-side
difference in posterior translation of 2.6 mm (range, —1 to 7 mm). The
mean corrected side-to-side difference in anterior tibial translation was
<3 mm for fourteen of the twenty-five patients and was >5 mm for three.
The remaining eight patients had 3 to 5 mm of increased anterior tibial
translation compared with that on the uninvolved side. The mean corrected
side-to-side difference in posterior tibial translation was <3 mm for
fifteen of the twenty-five patients and was >5 mm for three. The remaining
seven patients had a 3 to 5 mm of increased corrected posterior tibial
translation compared with that on the uninvolved side.
The final overall IKDC rating was nearly normal for eleven knees, abnormal
for twelve, and severely abnormal for eight. No knee received a normal overall
IKDC rating. Ten of the eleven knees that received a nearly normal overall
IKDC score had been treated acutely. Only one nearly normal knee had been
treated chronically. Equal numbers of severely abnormal knees were found in
the acute and chronic groups, but the percentages of the total were 21% and
33%, respectively. Of the knees with a severely abnormal overall IKDC rating,
five received this rating because of activity-related symptoms and three
received it because of flexion loss.
Complications included postoperative stiffness in four patients (Cases 4,
7, 13, and 14; see Appendix), all of whom had undergone acute reconstruction.
All four knees were treated with manipulation with the patient under
anesthesia. Three of the four knees were manipulated because of loss of
flexion, and one (Case 14) underwent arthroscopic lysis of adhesions at the
time of manipulation because of loss of extension. Of these four patients, one
(Case 14) had a contralateral grade-I open tibial fracture with a compartment
syndrome that required acute release at the time of presentation. As a result,
this patient did not receive adequate physical therapy after the initial
reconstruction. The time from the initial surgery to the manipulation for
these four patients was nine, eleven, nine, and thirty weeks (mean, 14.8
weeks). Manipulation increased the total arc of motion by an average of
51° (range, 25° to 90°) at the time of manipulation and by an
average of 55° (range, 28° to 106°) at the time of final
follow-up. Two patients had residual flexion contractures of 5° and
9°, and all patients had flexion of =115°.
Our goal in this study was to review the results of our protocol for
surgical and postoperative management of knee dislocations. We found that
allograft reconstruction provides a good functional result in the majority of
patients. Subjective functional results were acceptable for patients who
underwent the ligament surgery within the first three weeks after the injury.
The scores on all three rating scales used in the evaluation showed this
trend. Most patients had only slight symptoms and functional limitations
during activities of daily living. Many patients were able to return to sports
activities, although many had subjective symptoms and functional limitations.
Patients who underwent surgery within the first three weeks after injury
tended to have higher subjective scores. However, only the difference in the
score on the Sports Activity Scale of the Knee Outcome Survey reached
significance (p = 0.04).
Objectively, both the acutely and the chronically treated patients obtained
a good range of motion. On examination, most knees were stable. Residual
laxity of the posterior cruciate ligament was more common in the chronically
treated patients. In addition, residual valgus laxity was more prevalent in
the patients who underwent delayed repair of the medial collateral ligament.
These findings are consistent with those of other studies on the surgical
treatment of dislocated
knees12,22.
Clinically, however, the majority of patients did not report instability
unless they attempted strenuous manual labor or sports activities requiring
aggressive changes in direction or pivoting. In summary, our standard
management for knee dislocation seems to provide good structural and
functional results for the majority of patients.
Shelbourne et al. reported their experience with the management of
low-velocity knee dislocations in a series of twenty-one patients who had been
treated with several different nonoperative and operative
approaches24. They
recommended replacement of the posterior cruciate ligament with a patellar
tendon autograft along with repair of the medial collateral ligament and
lateral structures, whereas tears of the anterior cruciate ligament were not
treated. In addition, they recommended delaying ligament replacement when the
medial structures were involved (and the lateral side was normal) until the
patient obtained >90° of flexion, nearly full extension, and good
strength. They reported satisfactory results in nine patients treated in this
manner and believed that the arthrofibrosis potentially associated with
concurrent replacement of the anterior cruciate ligament or acute repair of
the medial collateral ligament could be avoided. Across all treatment groups,
the patients had an average extension loss of 3° and flexion loss of
15°. This range of motion was comparable with that in our series. Only 19%
of the patients were able to return to their preoperative level of athletic
competition.
Yeh et al.25
also reported on isolated replacement of the posterior cruciate ligament after
knee dislocation. Repairs of the collateral ligaments, capsule, and meniscus
were performed "as necessary." All replacements were performed
within twenty-five days after the injury. Yeh et al. reported good subjective
and functional results, with a mean Lysholm score of 84 points and mean
flexion of 129.6°. However, three of their twenty-three patients required
arthroscopic lysis of adhesions.
Shapiro and
Freedman22 reported
satisfactory functional results in six of seven patients evaluated at an
average of four years following treatment of a knee dislocation with allograft
replacement of the anterior and posterior cruciate ligaments. Other injured
structures were treated with primary repair, and the operations were performed
at an average of ten days after the injury. The mean flexion was 118°, and
three patients had a flexion contracture of =5°. The mean Lysholm score
was 75 points, and there were three excellent results, three good results, and
one fair result according to the Meyers rating. Four of the seven patients
required manipulation under anesthesia and/or arthroscopic lysis of adhesions
because of arthrofibrosis.
Fanelli et al.20
reported successful cruciate ligament replacement with either patellar tendon
autografts or fresh-frozen allografts in twenty patients who had sustained a
knee dislocation. Ten patients underwent the surgery acutely, and ten patients
underwent delayed replacement. In contrast to our findings, they did not note
differences between the acutely and chronically treated groups with the
ligament-rating scales that they used. These authors therefore recommended
that replacement for the treatment of injuries of the anterior cruciate
ligament, posterior cruciate ligament, and posterolateral corner be delayed
for at least two to three weeks and replacement for the treatment of injuries
of the anterior cruciate, posterior cruciate, and medial collateral ligaments
be delayed for six weeks to allow healing in a brace. The postoperative
Lysholm scores averaged 91.3 points in their series.
Noyes and
Barber-Westin21
reviewed the results in eleven patients who had undergone mostly allograft
replacement of the cruciate ligaments, lateral collateral ligament, and
posterolateral corner structures. Seven patients were treated acutely and four
patients were treated chronically. Notably, the patients who had undergone
delayed reconstruction had lower overall ratings and more subjective
difficulties with sports activities than did the patients treated acutely.
Wascher et al.11
reported on thirteen patients who had undergone allograft replacement of the
anterior and posterior cruciate ligaments. Nine patients had an acute injury,
and four had a chronic injury. Wascher et al. also noted better results after
early reconstructions than after late reconstructions. Mild residual laxity of
the posterior cruciate ligament was common, as it was in our series. The
Meyers score was excellent or good for eleven of their patients, the Lysholm
scores averaged 88 points, and the IKDC overall rating was nearly normal for
six knees, abnormal for five knees, and grossly abnormal for one knee. IKDC
scores were not available for one patient. Two patients required postoperative
manipulation and arthroscopic lysis of adhesions because of
arthrofibrosis.
Our results are comparable with those in other series of patients who had
undergone allograft reconstruction of the cruciate ligaments following knee
dislocation11,41-43.
On the basis of these results, we advocate early combined replacement of both
cruciate ligaments and repair or replacement for complete collateral or
capsular injuries. A review of the literature revealed that several surgeons
have advocated delayed intervention in patients who have a complete injury of
the medial collateral
ligament20,24.
We performed early primary repair of medial collateral ligaments with complete
injuries. The timing of surgery, and specifically acute reconstruction of the
anterior cruciate and medial collateral ligaments in the setting of knee
dislocation, did not seem to increase the rate of arthrofibrosis in our
series.
We favor the use of allograft rather than autograft for patients with a
knee dislocation to avoid the additional surgical morbidity and increased
surgical time associated with harvesting of the graft. In our series of
thirty-one patients who had a total of sixty allograft cruciate
reconstructions, there was only one graft failure that required a reoperation
(Case 16; see Appendix).
The relationship between range-of-motion measurements and laxity and the
resulting functional limitations and disability is not a direct
one44. From the
patients' perspective, functional limitations and disability are of utmost
importance. Thus, we believe that the primary outcome measure for clinical
research, including this study, should be the patients' perception of their
functional limitations and disability. Measures such as range of motion and
laxity should be considered to be secondary outcome measures. As a result, we
chose to use several measures that focus on the patients' perception of their
function and disability, including the Lysholm Knee Scale, the Meyers rating
scale, and the Activities of Daily Living and Sports Activities Scales of the
Knee Outcome Survey. The average Lysholm score for our patients, 87 points,
was comparable with that in other
reports11,20,22,25,
despite a large percentage of chronically treated patients in our series. The
Meyers ratings for our patients were similar to those reported by others as
well11,22.
Seventy-four percent received an excellent or good rating, which implies that
the majority of our patients were able to return to work or to their previous
level of activity with no or minimal pain and instability. As indicated by the
Knee Outcome Survey, the patients had fewer symptoms and functional
limitations during activities of daily living than they did during sports.
On the basis of the results of this study, we have made several changes in
our surgical management of these complex injuries. We no longer use a
tourniquet because the combined tourniquet time exceeded two hours in
twenty-six of the thirty-one patients. We have found that arthroscopic
visibility and identification of collateral and capsular structures can be
achieved without use of a tourniquet. Also, we no longer use an arthroscopic
leg-holder because we found it to be too confining for assessment of range of
motion and stability.
On the basis of our arthroscopic findings of various patterns of posterior
cruciate ligament injury, we have been more selective about preserving the
remaining components (anterolateral, posteromedial, or meniscofemoral) if they
are intact32. In
this series of patients, if the posterior cruciate ligament was replaced, we
removed all remaining components with an anterolateral single-bundle
procedure. We now identify and preserve any intact components and replace only
what is torn. We are most likely to do this in knees with an acute
dislocation, in which the meniscofemoral ligaments are usually intact and the
posteromedial component is occasionally still present.
Finally, since 2000, we have been performing double-bundle posterior
cruciate ligament replacement with use of an Achilles tendon allograft for the
anterolateral bundle and a semitendinosus autograft for the posteromedial
bundle in knees with a chronically deficient anterior cruciate ligament,
posterior cruciate ligament, and posterolateral corner. This change was based
on the results of our biomechanical studies and this retrospective
review45,46.
The overall IKDC rating for each knee was determined according to
guidelines described by Hefti et
al.40. According to
the IKDC knee-ligament-rating scale, no knee was normal, eleven were nearly
normal, twelve were abnormal, and eight were severely abnormal. Many times,
the overall IKDC score did not provide an accurate representation of the
patients' perception of the outcome, as evidenced by the fact that some
patients with an abnormal or severely abnormal overall IKDC rating had high
Lysholm, Knee Outcome Survey, and Meyers scores. Additional evidence of the
validity of the IKDC guidelines for patients with multiple ligament injuries
of the knee is necessary.
This study demonstrated that anatomic allograft reconstruction to treat all
associated knee injuries yields good functional results in patients with a
knee dislocation. However, our study was limited by the number of patients and
the heterogeneity of injuries, which is inherent to a series of patients with
knee dislocation.
In summary, replacement or repair to treat multiple ligament injuries
following traumatic knee dislocation provided satisfactory subjective
functional results, range of motion, and stability in the majority of the
patients in this series. Patients who underwent surgery within the first three
weeks after injury tended to have better subjective functional ratings and
better restoration of ligamentous stability. Although the majority of patients
had little difficulty with activities of daily living, the ability of patients
to return to high-demand sports and strenuous manual labor is less
predictable. Patients treated for chronic instability after knee dislocation
may have more functional limitations than those who are treated acutely. It is
important to discuss these issues with patients preoperatively so that their
expectations are realistic.
Tables showing data on all patients and the results of the follow-up
evaluation are 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).
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