Tibial plateau fractures

transcript

By Yasser Alwabli

• Anatomy• Mechanism of injury• Classification• Diagnosis (History, Physical

examination and Imaging)• Management• Complications

Objectives

• The tibial plateau is the proximal end of the tibia including the metaphyseal and epiphyseal regions as well as the articular surfaces made up of hyaline cartilage.

• AO defines tibial plateau as the metaphysis to a distal distance equal to the width of the proximal tibia at the joint line.

Anatomy

Distinction between medial and lateral condyles• Medial:o Slightly concave shapeo Larger in both width and length.

o Cartilage thickness ~ 3 mm• Lateral:o Convex o 2-3 mm superior (proximal) to

the medial.o Cartilage thickness ~ 4 mm

• Medial proximal tibial angle (MPTA) 85 – 90.

• Posterior slope ~ 9 degrees (Posterior proximal tibial angle)

• Both plateaus covered with hyaline cartilage.

• ITB to Gerdy’s tubercle

• Patellar tendon to anterior tibial tubercle

• Pes Anserine tendons (S, G, ST) to AM tibia ~ 7 cm below joint line

Muscle attachments

• Lateral meniscus– semicircular– covers 50 % of the plateau– Attached to PCL via

ligaments• Humphry (anterior)• Wrisberg (posterior)

– No attachment to LCL• Medial meniscus

– C-shaped– Thick posteriorly, so

promoting posterior stabilization.

– intimately attached to MCL

Menisci

• Four subdivisions: ACL, PCL, PM and PL corner ligament complexes.

• ACL:o Two bundles: AM tight

in flexion, PL tight in extension.

o Prevents anterior translation

o From PM corner of lateral femoral condyle to anterior tibial intercondylar area.

• PCL:o Two bundles: AL

tight in flexion, PM tight in extension.

o Prevents posterior translation

o From antermedial femoral condyle to posterior sulcus of tibia

Ligaments

• PM corner:o MCL and oblique popliteal

ligamento Prevents valgus instability

and PM translation of tibiao MCL:

o From medial femoral epicondyle

o Superficial and deep components

oDeep to medial mensicus

o Superficial to distal plateau

o PL corner:o Arcuate ligamento Popliteuso Posterolateral capsuleo Lateral collateral

ligamento Popliteofibular

ligamento Lateral head of

gastrocnemiius

Ligaments

• Common peroneal nerve:– The common

peroneal nerve courses around the neck of the fibula distal to the proximal tibia-fibula joint before it divides into its superficial and deep branches

• Popliteal artery – The trifurcation of

the popliteal artery into the anterior tibial, posterior tibial, and peroneal arteries occurs posteromedially in the proximal tibia.

Neurovascular structures

1. Force directed medially (valgus deformity) or laterally (varus deformity) or both.

2. Axial compressive force.3. Both axial force and force from the side.

Mechanism of injury

• Shatzker classification– Six types

• AO\OTA– Three types

Classification

• Type I:

o Split-wedge fracture of lateral plateau without any joint depression or impaction

o In young patientso Lateral meniscal

pathology may be present

Schatzker classification

• Type II:

o Split fracture of the lateral tibial condyle with associated impaction or depression of the articular surface

o Greater energy than type 1

o Commonly in fourth decade of life

• Type III:

o Pure depression of the lateral articular surface only.

oCommon in elderly

• Type IV:

o Split fracture of medial plateau with associated comminution of intracondylar eminence or medial plateau articular surface.

• Type V:

o This is a total articular fracture in the configuration of an inverted “Y,” with both plateaus separated from each other and from the distal tibia. The nonarticular intercondylar eminence region remains largely intact.

• Type VI:

o Tibial Plateau Fx with Metaphyseal - Diaphyseal Separation

AO/OTA Classification

• Type A - Extraarticular• Type B - Partial Articular• Type C - Intra-articular and Metaphyseal

Posterior shear fracture• Pure posterior

fracture fragments• Does not fit into

Schatzker’s classification, may be bicondylar, or a knee dislocation variant.

• Needs posterior approach

• Usually cruciate ligament avulsions.

Intercondylar eminence fracture

• Injury to collateral ligaments occur in 7% to 43%

• ACL rupture up to 23 %• Meniscal injuries up to 50 % (in split type,

may be incarcerated)• Any widening of the femoral-tibial

articulation greater than 10° upon stress examination indicates ligamentous insufficiency

Associated injury

• History :• Age• Comorbidities• Patient activity level, employment, recreational …• Mechanism of injury• Direction of force

• Physical examination:• ATLS• Open wounds, deformity, swelling, instability, crepitus• Test of compartment syndrome• Vascular assessment; API and ABI• Distal pulses• Assessment and monitoring of soft tissue swelling

Diagnosis

• Plain X-Ray:• Supine AP and lateral view for all patients• Internal and external oblique view• Obtain contralateral AP and Lateral (compare)• Tibial plateau view: AP with knee extended and beam

directed 15 degrees caudally

• CT scan:• increases the diagnostic accuracy• indicated in cases of articular depression• shown to increase the interobserver and intraobserver

agreement on classification in tibial plateau fractures• excellent adjuncts in the preoperative planning

Radiology

• MRI:• alternative to CT scan or arthroscopy• osseous as well as the soft tissue components

of the injury• cost prohibitive for use in standard situations

• Duplex US and Arteriography:– To evaluate associated arterial injury.

Radiology

• Non-operative management:– Indicated for non-displaced or minimally

displaced fractures• Method:

– Protected weight bearing and early range-of-knee motion in a hinged fracture brace.

– Isometric quadriceps exercises and progressive passive, active-assisted, and active range-of-knee motion exercises.

– Partial-weight bearing (30-40 Ib) for 8 to 12 weeks with progression to full weight bearing.

Management

• Indications:– Accepted range of articular depression varies

from < 2 mm to 1 cm– Instability > 10 degrees of nearly extended

knee compared to the contralateral side– Open fractures– Associated compartment syndrome– Associated vascular injury

Operative treatment

• Goals of treatment:– reconstruction of the articular surface– re-establishment of tibial alignment

• Treatment involves reducing and buttressing of elevated articular segments with bone graft

• Soft tissue reconstruction including menisci and ligaments

• Spanning external fixator as a temporizing measure in patients with high-energy injuries or significant soft tissue injury.

• Arthroscopy

Principles of management

• Plates and screws, screws alone or external fixation. (The choice of implant is related to the fracture patterns, degree of displacement, and familiarity of the surgeon).– Plates and screws:

• Functions: buttressing against shear forces or neutralize rotational forces

• Thinner plate• Percutaneous plating• Double plating

– Screws alone:• Simple split fractures, or depressed that are

elevated percutaneously

Implant options

• External fixation:– Advantages of external fixation include

• minimal soft tissue dissection • ability to alter frame stiffness and thus control

compression across comminuted fracture fragments.• can be dynamized during fracture healing, which

may help if delayed or nonunion occurs in the metaphyseal regions.

• provides excellent stability in cases where there is severe soft tissue or bony defect.

• allows for correction if there is a malalignment or deformity.

– spanning external fixators

Implant options

• Type I:– Closed reduction then stabilized cancellous lag

screws with washers to gain compression.• Type II:

– OR and elevation of depressed fragment– Bone graft is placed to support the elevated

fragments– Screws are placed across the reduced split

fracture fragments in lag mode

Operative treatment

• Type III:– elevation through cortical fenestrations– supported with subchondral screws and bone

• Type IV:– requires a medial buttress plate to counteract

the shear forces acting on the medial plateau– lag screws alone are not sufficient to stabilize

these fractures

Operative treatment

• Type V:– locking plates, laterally placed plates with

screws that lock to the plate creating a fixed angle construct provide enough stability to counteract forces seen by the medial tibial plateau.

Operative treatment

Operative treatment• Type VI:

– Following articular reconstruction, the articular segment has historically been stabilized to the tibial shaft using a single plate, double plates, a single plate and a contralateral two-pin external fixator, or a thin-wire fixator. If the fracture is transverse, a single plate will suffice. Oblique fracture lines exiting the opposite cortex require a second plate or external fixator to resist shearing forces.

• Early:– most commonly is infection (3 – 38 %)

• Superficial• Deep

– Thromboembolic complication (DVT, PE)• Late:

– Painful hardware– Loss of fixation– Posttraumatic arthritis– malunion

Complications

Tibial plateau fractures

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