Deforming Force in Lower Limb Fracture Fix

Deforming Force in Lower Limb Fracture

Presented by: Ahmad Tho Tuching

Supervisor :Dr. Jainal Arifin Sp.OT

DEPARTMENT OF ORTHOPEDIC AND TRAUMATOLOGY

FACULTY OF MEDICINE

HASANUDDIN UNIVERSITY

MAKASSAR

2012

DefinitionDeformation=a change in the shape or size of

an objectForce=An applied workDeforming Force=a change in the shape or

size of an object due to an applied force how that can make structural failure in lower

limb of the human.

Deforming force can be a result of tensile (pulling) forces, compressive (pushing) forces, shear, bending or torsion (twisting).

It can be as a result of applied Internal force or External Force

Internal Force:Related Atachment of Structures to the Bone. Ex: Muscle

External Force: Applied force outside of the body. (Mechanism of Trauma)

Lower Limb Fracture can involve structures as follow:

-Pelvis - Femoral Shaft -Calcaneus-Acetabulum - Distal Femur -Talus-Femoral Head - Patella -

Metatarsal-Femoral Neck - Tibial Plateau -

Phalanges-Intertrochanter - Tibial Fibula shaft-Subtrochanter - Ankle

Pelvic Structure Ilustration

Medial View

LateralView

PelvisA Unstable injury is defined as one that can’t with

stand normal physiologic forces without abnormal deformation

AP Force and Lateral ForceAP Force: External Rotated of hemipelvisLateral Force: Most Common Type and depend on

location of applied forceExternal rotation abduction force: This is common in

motorcycle accidents. Force application occurs through the femoral shafts

and head when the leg is externally rotated and abducted.

This tends to tear the hemipelvis from the sacrum

AcetabulumMainly caused high energy blunt traumaPattern determined by force vector and

position of femoral head at impactER and Abducted Hip causes anterior column

injuryIR causes Posterior Column InjuryHip Flexion: Posterior wall to inferior positionDecrease degree of the hip flexion tends to

involve superior portion of posterior wall

Femoral HeadMost femoral head fractures are secondary to MVA

with axial load transmission proximally through the femur.

If the thigh is neutral or adducted, a posterior hip dislocation with or without a femoral head fracture may result.

These fractures may be the result of avulsion by the ligamentum teres or cleavage by the posterior acetabular edge.

In anterior dislocations, impacted femoral head fractures may occur because of a direct blow from the acetabular margin.

Femoral NeckLow-energy trauma: In Elderly

Direct: A fall onto the greater trochanter (valgus impaction) or forced ER of the LE impinges an osteoporotic neck onto the posterior lip of the acetabulum (resulting in posterior comminution).

Indirect: Muscle forces overwhelm the strength of the femoral neck.

High-energy trauma: MVA or fall from significant Height

Cyclical loading-stress fractures: These are seen in athletes, military recruits, ballet dancers; patients with osteoporosis and osteopenia are at particular risk.

Intertrochanter the region between the greater and lesser trochanters of

the proximal femurDeforming muscle forces will usually produce shortening,

external rotation, and varus position at the fracture.Abductors tend to displace the greater trochanter

laterally and proximally.The iliopsoas displaces the lesser trochanter medially

and proximally.The hip flexors, extensors, and adductors pull the distal

fragment proximally.

SubtrochanterArea between the lesser trochanter and a

point 5 cm distal to the lesser trochanterAbduction by gluteusFlexion of hip by iliopsoasER by short eksternal rotatorsPulled the distal fragment into varus

and proximally bi adductorsOn PE is found Shortened and Rotated of LE

Femoral shaftOrthopaedic EmergencyThe femoral shaft is subjected to major muscular

deforming forcesAbductors (gluteus medius and minimus): abduct the

proximal femurIliopsoas: It flexes and externally rotates the proximal

fragmentAdductors: They span most shaft fractures and exert a

strong axial and varus load to the bone by traction on the distal fragment.

Gastrocnemius: flexes the distal fragment.Fascia lata: It acts as a tension band by resisting the

medial angulating forces of the adductors.

Deforming muscle forces on the femur; abductors (A), iliopsoas (B), adductors (C), and gastrocnemius origin (D). The medial angulating forces are resisted by the fascia lata (E). Potential sites of vascular injury after fracture are at the adductor hiatus and the perforating vessels of the profunda femoris.

Distal Femur The distal femur includes both the supracondylar and condylar regionsThe supracondylar area of the femur is the zone between the femoral condyles and the junction of the metaphysis with the femoral shaft.

Deforming forces from muscular attachments cause characteristic displacement patterns:

Gastrocnemius: This flexes the distal fragment, causing posterior displacement and angulation.

Quadriceps and hamstrings: They exert proximal traction, resulting in shortening of the lower extremity.

Patella The largest sesamoid bone in the bodyThe quadriceps tendon inserts on the superior pole and the

patellar ligament originates from the inferior pole of the patellaThe medial and lateral extensor retinacula are strong longitudinal

expansions of the quadriceps and insert directly onto the tibia.The most common MOI is secondary to forcible quadriceps

contraction while the knee is in a semiflexed position. The intrinsic strength of the patella is exceeded by the pull of the

musculotendinous and ligamentous structuresTransverse fracture Pattern

Possibility inferior pole CommunitionThe degree of displacement of the fragments suggests the degree

of retinacular disruption.Then Active knee extension is usually lost.

Tibial Plateau The tibial plateau is composed of the articular surfaces of the

medial and lateral tibial plateaus, on which are the cartilaginous menisci.

Medial articulate surface is stronger than lateral side Fractures of the tibial plateau are caused by a varus or valgus

force combined with axial loading (a pure valgus force is more likely to rupture the ligaments).

The momentary varus angulation may be severe enough to cause a rupture of the lateral collateral ligament and a traction injury of the peroneal nerve.

Schatzker Classification

Tibia Fibula Shaft Related to subcutaneous position, the tibia is more

commonly fracturedMOI:

A twisting force causes a spiral fracture of both leg bones at different levels; an angulatory force produces transverse or short oblique fractures, usually at the same level.

Indirect injury is usually low energy; with a spiral or long oblique fracture one of the bone fragments may pierce the skin from within.

Direct injury crushes or splits the skin over the fracture; this is usually a high-energy injury and the most common cause is a motorcycle accident.

AnkleThe ankle is a complex hinge joint composed

of articulations among the fibula, tibia, and talus in close association with a complex ligamentous system

CalcaneusMost Tarsal fracturesIntraartikular and ekstraartikular type

MetatarsalMOI

Direct: This most commonly occurs when a heavy object is dropped on the forefoot.

Twisting: This occurs with body torque when the toes are fixed, such as when a person catches the toes in a narrow opening with continued ambulation.

Avulsion: This occurs particularly at the base of the fifth metatarsal.

Stress fractures: These occur especially at the necks of the second and third metatarsals and the proximal fifth metatarsal.

PhalangesThe first and fifth digits are in especially

vulnerable positions for injuryA direct blow such as a heavy object dropped

onto the foot Transverse FractureA stubbing injury is the result of axial

loadingSpiral or Oblique Fracture

ReferencesAnonymous. Deformation (Engineering). 2012

[cited 2012 Sept 22]. Available from: http://www.wikipedia/Deformation_(engineering).htm

Koval KJ, Zuckerman JD. Handbook of Fractures. 3thed. Newyork: Lippincott Williams and Wilkins;2007.

Solomon L, Warwick D, Nayagam S. Apley’s System of Orthopaedics and Fractures. 9thed. London: Hodder Arnold;2010.

Thompson JC. Netter’s CONCISE ORTHOPAEDIC ANATOMY. 2nd ed. New York: Elsevier;2010.