Biomechanics of Quadrilateral socket

Biomechanics of Quadrilateral socket

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  BANGLADESH HEALTH PROFESSIONSINSTITUTE BHPI-CRP School of Prosthetics and Orthotics Biomechanics of Quadrilateral Socket Shishir Chandra Bin Intern PO (01)
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  Content  Objective  Introduction Quadrilateral socket  Quadrilateral socket shape  Quadrilateral socket wall  Biomechanical principles of Quadrilateral socket  Summary
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  Objective To know aboutQuadrilateral socket To know about the socket wall To know about Quadrilateral socket biomechanics
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  Introduction Clinicians have 2types of prosthetic sockets for patients with a transfemoral amputation : 1. Quadrilateral socket introduced in the 1950s 2. Ischial containment socket introduced in the 1980s For many years , the quadrilateral socket was acceptable to clinicians and patients alike . But QL socket has some disadvantage , and that’s why Nowadays IRC socket has become more popular .
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  Quadrilateral socket  Quadrilateralsocket refers to socket shape viewed in transverse plane .  Quad = four  Four walls are  Medial  Anterior  Lateral  Posterior
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  Quadrilateral socket shape
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  Quadrilateral socket wall Quadrilateral socket has four walls . Four walls are  Medial wall  Anterior wall  Lateral wall  Posterior wall
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  Quadrilateral socket biomechanics Quadrilateralsocket biomechanics :  Total contact  Firmness and softness of tissue  The effect of sloped surfaces on stump/socket pressures  High anterior wall  Stabilization of the femur and pelvis  Initial flexion of the socket
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  Quadrilateral socket biomechanics Totalcontact :  Good blood circulation(prevent oedema)  Increased surface area(reduced pressure)  Improved proprioception(easy to control prosthesis)
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  Quadrilateral socket biomechanics Firmnessand softness of tissue:  Contracted large muscles are related to firm tissue (need relief )  Femoral triangle and lateral surface is soft tissue area(increase pressure over these areas)
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  Quadrilateral socket biomechanics Theeffect of sloped surface on stump:  The best supporting surface to take weight is a horizo ntal surface  The TF stump does not tolerate end bearing  Weight is distributed proximally at the Ischial Tuberosi ty area
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  Quadrilateral socket biomechanics Highanterior wall:  Ischial tuberosity tends to slide forward (For this posterior counter force needed )  Pelvis also rotates anteriorly  That’s why anterior wall is made 5 cm higher than posterior wall
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  Quadrilateral socket biomechanics Stabilizationof the femur and pelvis:  Pressure applied laterally during casting and rectificati on( to resist abduction of femur )  This adduction of femur stabilise the pelvis to drop on the afected side  This reduces lateral trunk bending
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  Quadrilateral socket biomechanics Initialflexion of the socket :  Gluteus maximus and hamstrings more effect in generating hip extension forces  Helps to maintain the ischial tuberosity on its seat  It improves the gait of the amputee to reduce lumber lordosis at heel off.
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  Summary Quadrilateral socket has6 biomechanical principles . Among them 1st three are main principles to make a proper TF socket . Quadrilateral socket walls have functions to work the socket properly . If any wall does not work properly then there will be problem with the function of the prosthesis .