Traumatic knee dislocations are rare injuries that require careful evaluation and management. According to the document, knee dislocations often result from high-energy injuries like motor vehicle collisions or falls. A thorough examination is needed to assess vascular and neurological status. Imaging can identify associated fractures. While some stable injuries may be treated non-operatively, unstable injuries or those with ligament disruption typically require surgical reconstruction. Complications may include neurovascular injuries, infections, and long-term issues like osteoarthritis. Early surgical intervention within 3 weeks of injury may lead to better outcomes compared to delayed treatment.

1. Traumatic Knee
Dislocations
Evaluation, Management, and Surgical
Treatment
James R. Lachman, Saqib Rehman,Paul S. Pipitone
Orthop Clin N Am - (2015)
PRESENTED BY:
DHRUV GOEL

2. INTRODUCTION
• Incidences :< 0.02% of all musculoskeletal injuries.
• This number is most likely an underestimate caused by spontaneous
reductions and missed diagnosis.
• Most knee dislocations are the result of high-energy mechanisms .
• Careful history and physical examination in a systematic approach will
aid in identifying patients at risk for this injury.

3. MECHANISM
• M:F=2.5 :1
• High-energy mechanism, the most common:
• motor vehicle collision (up to 50%).
• sports injuries (up to 33%)
• simple falls(up to 12%)
• fourth subset, designated ultralow energy, has been recently described.

4. Classification:
The first description of a knee dislocation : closed versus open
Incidence : open knee dislocations varies between sources from 15% to
>35%

6. LATERAL DISLOCATION
ANTEROLATERAL DISLOCATION

8. V
C
N
III L ACL / PCL / LCL+PLC MCL intact
IV ACL / PCL / MCL / LCL+PLC
III M ACL / PCL / MCL LCL+PLC intact
Schenck 1992
II
arterial injury
nerve injury
fracture dislocation
Anatomic Classification of Knee Dislocations
I single cruciate + collateral
ACL + collateral
PCL + collateral
ACL / PCL collaterals intact

9. EVALUATION
Acute Assessment
Initial evaluation
PRIMARY SURVEY
ATLS support protocol
SECONDARY SURVEY
careful evaluation of the
neurologic and vascular status of the
affected limb

10. • In patients with a spontaneously reduced knee dislocation, identifying
those at risk for vascular or soft tissue compromise is much more
difficult.
• Subtle signs of bruising or swelling surrounding the knee may suggest
capsular disruption.

11. Vascular Examination
• The incidence ranges in the literature from less than 5% up to 65%.
• Historically,high-energy mechanisms resulting in a hyperextension
moment were thought to be more likely to cause vascular compromise.
• Recent review of available literature did not demonstrate an association
between direction of dislocation and vascular insult.

12. • A standard examination includes palpating dorsalis pedis and posterior
tibial pulses bilaterally and assessing for any asymmetry.
• In the absence of any asymmetry, further assessment is not necessary.
• Bilateral ankle-brachial-indices (ABI) evaluations in the initial
assessment is critical.
• cutoff <0.9, the sensitivity of ABI in detecting vascular injury requiring
surgical intervention approaches 100%.

13. Routine Angiogram
• concept of a routine angiogram for all suspected knee dislocations has been
the matter of debate.
Currently,
Angiography
(routine computed tomographic angiography [CTA] or magnetic resonance
angiography [MRA] )
is recommended for patients demonstrating insufficient perfusion or any
asymmetry in physical examination

14. • Green and Allen described the importance of timely identification of vascular
injury.
• Of the patients who were identified with vascular compromise,
those treated surgically within 8 hours had a significantly
lower amputation rate (11%) than those treated after 8 hours (86%)

15. Vascular Anatomy
• Popliteal artery at risk for being
tethered
• Adductor hiatus
• Soleus arch
• If blood flow through popliteal artery
disrupted :blood supply is inadequate
distally

18. Neurologic Examination
• The physical examination should include a detailed neurologic examination
including
Sensory examination:
Sensation in the
Tibial
Deep peroneal
Superficial peroneal
distributions to light touch, pinprick,
and temperature if available
Motor examination
including
flexor and extensor hallucis longus,
tibialis anterior
gastrocnemius
is important to establish the baseline
function

19. • The incidence of nerve injury : 4.5% to 40.0%.
• Most commonly, the common peroneal is the injured nerve, though
isolated tibial nerve palsy has been reported.
• The fibular neck tethers the CPN proximally, and the fibrous arches of the
intermuscular septum tethers distally.
• Contrary to intuition, the reported incidence of nerve injury in ultralow-
energy knee dislocations is higher (44.4%) than the incidence in the
higher-energy trauma patients.

20. Intraoperative photograph showing near-complete disruption of the common
peroneal nerve at the popliteal hiatus after knee dislocation

21. RADIOGRAPHIC EVALUATION
Immediate
• After confirmation of limb perfusion and before physical examination
of ligamentous integrity, standard views of the knee are obtained
immediately after reduction.
• Associated fracture has a reported incidence ranging from 10% to
20%.
• Fibular head (arcuate fracture), tibial spine, and lateral tibial condyle
(Segond fracture)avulsions are common.

22. Medial joint space widening Classic arcuate fragment Segond fracture

23. Secondary
• After the limb is reduced, vascular injury is ruled out and grossly
unstable knees are stabilized advanced imaging is appropriate.
• Computed tomography (CT), MRI, or both may be appropriate

24. EXAMINATION OF KNEE STABILITY
Clues to ligament injury in a spontaneously reduced knee dislocation are
• any asymmetry in the joint space
• minor subluxations in any direction
• Segond fractures.
• Examination of ligamentous integrity is often limited secondary to patient
discomfort.
• Intra-articular injection of lidocaine after aspiration of any hemarthrosis
can aid in patient comfort.

25. Anatomy – 4 groups of ligaments
• ACL
• PCL
• MCL, posteromedial capsule
• LCL & PLC (popliteofibular
ligament, popliteus, capsule, ITB,
biceps femoris)

27. Knee Examination
• Special Tests (ligaments)
• Valgus and Varus Stress Tests
(MCL/LCL)
• Lachman’s & Anterior Drawer
(ACL)
• Posterior Drawer & Posterior Sag
Test (PCL)
• Postero-lateral corner

28. MCL Stability
Apply Valgus
or Medial
Stress
AT 30°
FLEXION
LCL Stability
Apply Varus
or Lateral
Stress

29. Test of ACL
At 90° Flexion
At 30° Flexion
(more sensitive)

30. Posterior Sag
Posterior Drawer

31. • The Lachman test and anterior drawer :ACL rupture.
• Varus/Valgus stressing : MCL/LCL compromise.
• Posterior sag :PCL disruption
• are the most reliable maneuvers in the acute setting.
• The most common ligament injury pattern is both cruciates and the medial
ligament complex .
• The posterolateral corner (PLC) is second most common.
• In addition, reports of tendon injury (patella, popliteus, and biceps femoris)
are present.

32. • Intraoperative photographs demonstrating varus and valgus stress
examination and fluoroscopic images:

33. Reduction Technique
After palpation of the surface anatomy, gentle in-line traction
attempting to bring the knee into extension is enough to reduce a
dislocated knee.
• No manual pressure be used to aid in any direction,especially in the
popliteal fossa, to avoid iatrogenic neurovascular injury.
• DIMPLE SIGN: closed reduction will be unsuccessful.

34. SKIN DIMPLING
DIMPLE SIGN
Buttonhole of medial femoral
condyle through soft tissues
(capsule, MCL, retinaculum,
vastus medialis)

35. Closed Reduction Maneuver
POSITION of DISLOCATION
(Tibia relative to Femur)
•Anterior
• Traction & elevation of distal femur
•Posterior
• Traction & extension of proximal tibia
•Lateral / Medial
• Traction & correctional translation
•Rotational
• Traction & correctional derotation

36. • Once the knee is reduced, repeat neurolovascular examination.
• With any vascular compromise or asymmetry in ABI(< 0.9), surgical
exploration is warranted.

37. TREATMENT
Nonoperative Versus Operative Treatment
• Management of knee dislocations is a topic of hot debate.
• Direct ligament repair versus ligament reconstruction
• use of autograft versus allograft tissue for reconstruction
• arthroscopic versus open treatment
• and timing of treatment are all areas of controversy

38. Early Treatment
Arterial injuries
• Arterial injuries require immediate exploration and vascular surgery
consultation.
• Reexamination is an important mechanism to prevent a missed
arterial injury.
• An evolving ischemia, changing pulse examination, or change in ABI
measurements can all be detected if routine reexamination is part of
standard treatment

39. Ligament injuries
• Determination of ligamentous injury in the emergency room will
govern the next step.
Postreduction knee
UNSTABLE
Temporizing knee-spanning
external fixator may be placed to
provide stability
and allow soft tissues to calm
down
STABLE
Placement into a knee
immobilizer is recommended
instead of circumferential
splinting or casting

40. SURGICAL TECHNIQUE
Acute Surgical Intervention
• Acute ligament reconstruction (earlier than 3 weeks), should be done
as an open procedure because of the capsular disruption precluding
arthroscopic assistance.
• If the PLC is involved, a lateral curvilinear incision is used.
• Access to the cruciates and MCL : a midline skin incision with medial
para-patellar arthrotomy.
• Posteromedial corner :Posteromedial approach

41. Sequence of Ligament Reconstruction
• Cruciate ligament reconstruction typically precedes PLC reconstruction
• PCL ACL COLLATERAL LIGAMENTS
PLC RECONSTRUCTION

42. Delayed Surgical Intervention
Arthroscopy is a preferred method
• Direct repair of the collaterals is no longer possible and
reconstruction with autograft or allograft is necessary.

43. Postoperative Complications
• Neurovascular injury
• tourniquet problems
• wound problems
• compartment syndrome
• complex regional pain syndrome
• knee stiffness
• persistent laxity
• osteonecrosis
• posttraumatic osteoarthritis
• Deep vein thrombosis

44. Outcomes
• Levy and colleagues conducted a systematic review that supports early
operative intervention defined as within 3 weeks compared with delayed
intervention
• Higher-energy injuries were shown to have inferior outcomes to lower-
energy mechanisms
• Lower-energy injuries were correlated with an increased incidence of
neurological injuries
• The incidence of posttraumatic osteoarthritis has been reported as high as
87%

45. Key points
• Knee dislocation is a relatively uncommon but often missed diagnosis
leading to significant morbidity.
• Serial examination of a suspected knee dislocation is essential in the
prevention of missed arterial injury.
• Currently, angiography is recommended for patients demonstrating
insufficient perfusion or any asymmetry in physical examination.

46. • Clinicians must be aware of the existence of an irreducible knee
dislocation.
• Use caution during reduction and cognizant of signs (dimple sign,
excessive force required for reduction, joint asymmetry after
reduction attempt).

47. THANK YOU