Topic 11: Joint and Corset

Preferred location of the mechanical knee joint with respect to the anatomical knee

• 2 1/4" proximal to MPT

• At socket midline

• Upper joints should have a five degree anterior tilt so stops do not hit at full extension

• Joints should be parallel to thigh

• Contour joints as closely to socket as possible

• Drill holes distally and fasten to socket. This will allow for additional forward tilt of joints if necessary to prevent stops from hitting. Glass tape rest of joint.

• Contour and attach one joint, then the second

When sitting the limb should be

• lifted up out of the socket by 1/2” so it is not forced down onto the socket

• pushed forward by 1/4” so the limb is not pressed into the popliteal region, creating uncomfortable pressure

corset fit during standing/sitting

• Just proximal to the patella to aid in suspension

• 1” clearance between distal posterior aspect of the corset relative to the socket while sitting at 90 degrees

• Joints should move forward (anteriorly) on femur 1/2". This is equivalent to the residual limb coming up out of the socket once the corset is attached.

• Joints should move distally on femur 1/4" - 1/2". This is equivalent to the residual limb moving forward

Back Check Strap

• Prevents joints from making forceful contact

  • Minimizes joint wear

  • Minimizes joint noise

• Make with leather and parachute cord