Knee dislocations are uncommon and occur with a reported incidence of less than 0.02%
of
all orthopaedic injuries. These injuries are defined by complete disruption of the
integrity of the tibiofemoral articulation.
27
They are challenging injuries to manage and are associated with the risk of
potentially devastating immediate and short-term complications, including popliteal
artery injuries, common peroneal nerve injuries, acute compartment syndrome, and deep
venous thrombosis, and controversy still exists regarding their optimal treatment.
19,35,39
Despite the severity of these injuries, a recent systematic review has
demonstrated that some level of sport participation is possible after multiligament
knee
injuries (MLKIs) for more than half of patients, but returning to preinjury levels
of
sport after surgical treatment is low, at just 22% to 33%.
11,12,16
Bilateral knee dislocations occur even less frequently than unilateral injuries, and
the
literature contains sporadic case reports only.
2,10,18,24,26,30,36
In view of the guarded prognosis of unilateral knee dislocations with respect to
returning to preinjury levels of sport, it could be assumed that the results after
bilateral knee dislocations would be considerably less favorable. To our knowledge,
successful return to preinjury levels of sport in an elite athlete after bilateral
knee
dislocations has not previously been reported.
Case Presentation
Patient consent was obtained for this case report. A 25-year-old world-class downhill
skier sustained bilateral knee dislocations after a fall at a speed of approximately
120 km/h during an international competition in January 2017. He fell as he was
making a curve and collided against the track protection fence. He was transported
to a local hospital, where computed tomography angiography was performed to exclude
arterial injuries. Both knee dislocations were reduced approximately 1 hour after
the accident. No neurological deficit was detected on physical examination. Plain
magnetic resonance imaging (Figures
1 and 2) was
performed, and applying the classification described by Schenck,
33
the right knee was attributed a KD-V grade, which consists in
multiligamentous injury with periarticular fracture, and the left knee was
attributed a KD-IV grade, with an injury of ACL, PCL, LCL, and MCL.
Figure 1.
Magnetic resonance imaging of the right knee showing a (A) medial meniscal
avulsion (solid arrow), and fracture of the lateral tibial plateau (dashed
arrow); (B) complete rupture of the medial collateral ligament/posterior
oblique ligament (star) and proximal tibiofibular dislocation (circle); (C)
bicruciate rupture (dashed circle); and (D) fracture of the lateral tibial
plateau (dashed arrow).
Figure 2.
Magnetic resonance imaging of the left knee demonstrating a complete medial
collateral ligament/posterior oblique ligament tear (star), bucket-handle
tear of the medial meniscus (circle), and bicruciate rupture (dashed
circle).
A summary of injuries is provided in Table 1. The patient had undergone anterior
cruciate ligament (ACL) reconstruction of his right knee 2 years previously. After
immobilization with extension splinting, the patient was transferred to our
institution for definitive management by an experienced orthopaedic team with
surgeons specializing in sport-related injuries of the knee.
TABLE 1
Summary of Injuries Sustained by Each Knee
a
Right knee: Schenck grade KD-V
– Bicruciate rupture
– Complete MCL + POL rupture
– Avulsion of the posterior root of the lateral
meniscus with complete avulsion of both roots of the
medial meniscus
– Fracture of the lateral tibial plateau and proximal
tibiofibular dislocation
Left knee: Schenck grade KD-IV
– Bicruciate rupture
– Complete MCL + POL rupture
– Avulsion of the vastus medialis, medial
gastrocnemius, and posterior root of the medial
meniscus
– Lesion of the lateral collateral ligament, biceps
femoris, popliteus tendon, and posterolateral
corner
– Bucket-handle tear of the medial meniscus
– Longitudinal tear of the posterior horn of the
lateral meniscus
a
MCL, medial collateral ligament; POL, posterior oblique
ligament; KD-V grade, which consists in multiligamentous injury with
periarticular fracture; KD-IV grade, with an injury of ACL, PCL, LCL,
and MCL.
Single-stage surgery was performed on each knee to manage all reconstructions and
repairs. Because of the tibial fracture and the fibular head dislocation, the right
knee was addressed first, at 9 days after the fall, and the left knee was operated
on at 2 weeks after the fall.
In both knees, the surgical procedure commenced with arthroscopic evaluation and
repair of meniscal injuries using a low pump pressure to minimize the risk of
compartment syndrome. The tourniquet time for both knees was less than 1 hour
because it was only applied for the duration of meniscal surgery and the subsequent
lateral approach for safe exploration and identification of the peroneal nerve. In
view of the need to reconstruct multiple structures, a complete fresh-frozen
extensor mechanism allograft (Figure 3) was used to provide sufficient graft material
for each knee.
Table 2 provides
details of the ligament reconstruction performed, graft type, and fixation type.
Figure 3.
All grafts were obtained from a fresh-frozen single extensor mechanism
allograft for each knee.
TABLE 2
Graft Types Obtained From a Single Extensor Mechanism Allograft for Each Knee
and Type of Fixation Used for Each Reconstruction
a
Reconstruction Performed
Graft
Fixation
Right knee
ACL
BPTB allograft
Bone-screw
PCL
QT allograft
Bone-screw
MCL/POL
Single strip of allograft
Screw
Left knee
ACL
BPTB allograft
Bone-screw
PCL
QT allograft
Bone-screw
MCL/POL
Single strip of allograft
Screw
LCL/PLC
Single strip of allograft
Screw
a
ACL, anterior cruciate ligament; BPTB, bone–patellar
tendon–bone; LCL, lateral collateral ligament; MCL, medial collateral
ligament; PCL, posterior cruciate ligament; PLC, posterolateral corner;
POL, posterior oblique ligament; QT, quadriceps tendon.
With respect to the right knee, the lateral tibial plateau fracture and the proximal
tibiofibular dislocation were reduced and fixed with 4.5- and 3.5-mm metallic screws
(Figure 4). The medial
meniscal roots were reinserted through 2 bony tunnels, and the posterior root of the
lateral meniscus was appropriately repaired. The medial collateral ligament and
posteromedial corner were reconstructed with a single strip of allograft (Figure 5).
21
Using an all-inside bicruciate ligament reconstruction technique, the ACL and
posterior cruciate ligament (PCL) were reconstructed. The ACL graft was tensioned
and fixed before fixing the PCL in full extension, ensuring neutral anteroposterior
positioning of the tibia under the femur. The PCL was then tensioned with the knee
at 90° of flexion while applying anterior translation to the tibia to reduce the
posterior drawer without any risk of overcorrection.
23,37
Figure 4.
Postoperative radiographs of the right knee showing the reduction and
fixation of a lateral tibial plateau fracture and proximal tibiofibular
dislocation with 3.5-mm metallic screws and washers.
Figure 5.
The medial collateral ligament and posteromedial corner were reconstructed as
described by Lind et al
21
with the modification of an allograft rather than a semitendinosus
autograft. SM, semimembranosus tendon.
With respect to the left knee, the vastus medialis and medial gastrocnemius were
reinserted in their appropriate sites. The bucket-handle tear of the medial meniscus
and the posterior horn of the lateral meniscus were repaired with all-inside repair.
The posterolateral corner (PLC) was reconstructed using the modified LaPrade
technique of Versailles
25
(Figure 6), which
ensured anatomic reconstruction of the 3 main PLC stabilizers (PLC, popliteus
tendon, and lateral collateral ligament) to restore posterolateral stability of the
knee. For ligament reconstructions (ACL, PCL, medial collateral ligament, and
posterior oblique ligament), the same surgical techniques described for the
contralateral side were performed. Surgery lasted 4.0 hours for the right knee and
3.3 hours for the left knee, performed 1 week apart.
Figure 6.
The posterolateral corner (PLC) was reconstructed using the modified LaPrade
technique of Versailles,
25
which ensured anatomic reconstruction of the 3 main PLC stabilizers
(PLC, popliteus tendon, and lateral collateral ligament) to restore
posterolateral stability of the knee. Graft fixation was performed with a
single interference screw and a suture.
Postoperatively, the patient remained in an open cast for 45 days without
weightbearing but was immediately stimulated to focus on quadriceps isometric
contraction, with flexion between 0° and 30°. At 6 weeks postoperatively, removal
of
the screw from the tibiofibular joint was performed with manipulation under
anesthesia. The stability of the knees was evaluated and considered to be very good.
Partial weightbearing was allowed after 6 weeks and full weightbearing at 10 weeks.
Nine months after progressive strengthening and proprioception training as well as
management of the psychological aspects of rehabilitation, under the supervision of
the physical therapy team, athletic trainer, and ski federation psychologist, the
patient performed the K-STARTS test, reaching a score of 90.
4
Ten months after the accident, he was able to return to skiing; 666 days
after the accident, and after intensive training, he was asymptomatic and able to
return to the Alpine Ski World Cup, referring to his knees as ‘practically normal’
(Figure 7). The physical
examination findings at 2-year follow-up are demonstrated in the Supplementary
Video.
Figure 7.
(A) Partial weightbearing was allowed after 6 weeks and full weightbearing at
10 weeks. (B) The patient is shown 9 months after surgery performing the
K-STARTS test and reaching a score of 90. (C) Twenty months after the
accident, and after intensive training, the athlete was asymptomatic and
returned to the Alpine Ski World Cup without complaints, referring to his
knees as ‘practically normal.’
Discussion
This case report demonstrates that return to elite sport is possible after the
surgical management of bilateral knee dislocations. This is an important message
because, according to the systematic review published by Everhart et al,
12
the rate of return to preinjury levels of sport in competitive/elite athletes
after the surgical management of unilateral MLKIs is very low (22%-33%). Bilateral
knee dislocations occur much less frequently than unilateral MLKIs, and thus,
similar case series reporting return-to-sport data after this more severe injury
pattern are not available in the literature.
1,3,5
However, it would be logical to expect inferior outcomes when compared with
unilateral knee dislocations. This case report is therefore important in
demonstrating that return to elite sport is possible after bilateral knee
dislocations, and it is also useful to highlight some of the concepts that we
consider important in achieving optimal outcomes after MLKIs.
Hirschmann et al
16
have identified that timing of surgery significantly influences long-term
outcomes. Patients treated more than 40 days after an injury had to give up
professional sport more frequently than patients treated earlier. In their series
of
24 unilateral multiligament knee reconstructions performed between 1983 and 2006,
they reported that surgery was performed as early as possible after the injury but
only when soft tissue swelling had resolved and range of motion had been regained
to
minimize the risk of arthrofibrosis. Twelve patients were operated on within the
first week, 5 within 2 to 3 weeks, and 7 after 3 weeks. Despite this approach, they
reported that at a median follow-up of 8 years (range, 1-23 years), 38% of patients
had a flexion deficit and 25% an extension deficit. Our approach differed in that
surgery was deferred until the patient was able to demonstrate good quadriceps
activation. The interval between injury and the first surgical procedure was only
9
days because of the strong emphasis on frequent isometric quadriceps activation
exercises, which were commenced shortly after the dislocations were reduced in the
emergency department. Stiffness is a well-recognized and important complication
after knee dislocations treated with multiligament reconstruction.
15,22,28,34,40
To minimize the recognized risk of long-term stiffness,
9
both knees underwent planned manipulation under anesthesia as well as removal
of the screw from the tibiofibular joint at 6 weeks postoperatively. This procedure
consisted of improving range of motion by the progressive application of increasing
passive loads to increase the flexion-extension arc via the rupture of
intra-articular adhesions and scar tissue.
Hirschmann et al
16
also reported that persistent pain (42%) and instability (25%) were
additional frequent causes of failure to return to sport after the surgical
management of unilateral knee dislocations in elite athletes. The pathophysiology
of
both pain and instability in this setting is multifactorial, but consideration must
be given to graft choice and the avoidance of donor site morbidity. In the current
case, there was clearly an insufficient available autograft to complete all
reconstructions, and for that reason, the use of an allograft was mandated. However,
to prevent additional trauma to the knees, the use of an autograft was completely
avoided by using a single fresh-frozen (nonirradiated) extensor mechanism allograft
(per knee) to provide sufficient graft material for all reconstructions. It should
be recognized that the use of a fresh-frozen allograft in ligament reconstruction
is
still controversial, and both autografts and allografts have their advantages and
disadvantages.
6,7,29,31
However, it is useful to note that Tian et al
38
reported that comparable objective and subjective clinical results can be
achieved with the use of a fresh-frozen hamstring tendon allograft compared with an
autograft in ACL reconstruction and also that Grassi et al,
14
in a recent meta-analysis, showed similar outcomes for autografts and
allografts when irradiated grafts were excluded.
In general terms, another important consideration is that the literature clearly
demonstrates a strongly positive relationship between increasing annual surgical
volume and improved patient outcomes across a wide variety of surgical procedures.
Although this type of study does not exist for MLKIs, Schairer et al
32
reported that annual volume was a significant determinant of reoperation
rates after ACL reconstruction. Specifically, they reported a 29% decreased risk of
subsequent ipsilateral knee surgery for ACL reconstruction by surgeons performing
more than 35 cases per year.
32
Clearly, multiligament reconstruction is a considerably more complex surgical
procedure, and although a minimal annual volume is not defined, it seems logical
that this type of surgery is performed by high-volume centers only to achieve the
best possible outcomes. The senior author (B.S.-C.) of this case report has an
annual volume of ACL reconstruction of more than 650 cases and a multiligament
reconstruction annual volume of more than 30 cases per year.
Technically, the procedure of multiligament reconstruction and meniscal repair after
knee dislocations is very demanding. The gold standard remains a 2-stage procedure.
20
However, recent studies have shown evidence of benefits when a single-stage
procedure is performed.
8
Anatomy remains the key to success.
13
More than isolated classic reconstruction, anatomic repair of fresh soft
tissue, and protection with augmentation using an allograft is our philosophy. We
do
not recommend extensive debridement of the remnant tissue but mostly repair and
augmentation. With this philosophy in mind, some teams have even proposed early
repair using suture augmentation with promising results.
17
A further consideration, highlighted by previous authors, is that athletes and their
relatives, managers, and coaches often lack necessary understanding of the severity
of the injury and expect return to sport within 4 to 6 months after knee dislocations.
16
In our case, the athlete was able to return to his chosen sport 10 months
after his accident and to a competitive level after 20 months. Appropriate
expectations must be held to avoid complications associated with premature return
to
sport, and this also involves giving consideration to the severity of injury and
psychological factors.
41
In the case of our athlete, psychological follow-up and the K-STARTS test
(ACL-RSI) were used to allow the athlete to return to sport in a safer manner.
Conclusion
It is our opinion that important considerations for achieving optimal outcomes after
the surgical management of knee dislocations include a multidisciplinary approach
by
a specialist team, with an emphasis on early postinjury quadriceps activation
exercises, minimal delay between the injury and surgery, the experience level and
annual volume of the surgeon, avoidance of donor site morbidity, consideration of
planned manipulation at 6 weeks postoperatively, and realistic expectations of the
timing of return to sport. This case report demonstrates that return to elite sport
is possible after the surgical management of bilateral knee dislocations.
A Video Supplement for this article is available at http://journals.sagepub.com/doi/suppl/10.1177/2325967119845017