The Knee Joint Prosthesis

Question 1

What are the main components in the knee ?

Answer 1

Bones, Menisci, ligaments and muscles.

Question 2

What are the four main bones composing the knee ?

Answer 2

The patulla, the tibia, the femur and the fibula.

Question 3

What is the menisci ?

Answer 3

It a structure made of fibrocaetilage and it form joint sockets, it counteract the pressure load between the bones.

Question 4

Cite the principal ligaments and their role.

Answer 4

Lig patellae, lig collaterale tibiale and lig collaterak fibulare. The transerve ligament. The anterior and posterior cruciate that avoid displacement of tibia and femur. Together they connect bones to bones.

Question 5

Site the main extensors muscles the knee.

Answer 5

The rectus femoris, vastus mediale, vastus intermedius, vastus lateralis.

Question 6

Site the main flexors around the knee.

Answer 6

The semitendinosus, the semembranosus and the biceps femoris.

Question 7

What is the role of the patella ?

Answer 7

It slidedon the femur as the knee move, it basically is in charge of the force transmission from the femur to the tibia in addition to protect and stabilise the knee joint.

Question 8

Why is the knee joint really prone to chronic degenerative diseases?

Answer 8

longests bones, little coverage with soft part, no optimal fit of joint bodies, high loads in everyday life.

Question 9

What is the most common cause of chronic knee pain ?

Answer 9

The Osteoarthritis.

Question 10

What is the main problem of osteoarthritis ?

Answer 10

The cartilage is injured and the joint capsule (= Synovial membrane, fibrous membrane) is thickened. The joint space is narrowing. The surrounding bones are also injured.

Question 11

Site the three different types of knee arthroplasty ?

Answer 11

Unicompartmental ( opposing joint surfaces of the femur and tibia)- bicompartmental opposing joint on the femur and tibia) and theecompartmental (with patellar resurfacing)

Question 12

What is the most widely used components for femoral and tibia components ?

Answer 12

Titanium (or titanium alloy) and cobalt-chromium alloy.

Question 13

What is the tibial and patellar components ?

Answer 13

Polyethylene?

Question 14

What is the material for uncemented implants?

Answer 14

Uncemented (in tantalum or hydroxyapatite)

Question 15

How can the implants can be fixed ?

Answer 15

With cement (space between prothesis and skeleton is sealed)
Cement kess (through press fit)
Hybrid (cementless femur and cemented tibia).

Question 16

On what depends the decision of the material ?

Answer 16

Age, allergies, cost and the patients and the doctors decides together depending on previous success).

Question 17

What are the factors influencing successful knee replacement ?

Answer 17

Implant positioning, limb alignement ans soft tissue balancing.

Question 18

Site the different solution available to increase the success rate of knee injuries.

Answer 18

Sensor system from orthosensor, sensor system on research level, surgery aid sensor from orthalign that are three tupe of sensor assisted knee replacement.

Question 19

What is the principle of intelligent intro-operative systel for knee replacement surgery ?

Answer 19

it replaces standars plastic tibial trial spacer block. it is used to optimize implant placement but it is only used during the operation and it doesn’t allow post op monitoring.

Question 20

What was the principle of the force measuring knee implant publication in 2014 ?

Answer 20

It was aimed for post operative measurements. It measures the forces for different angles. In this publication it has only be tested with robotic knee.

Question 21

What is the aim of the sensor-assisted knee replacement ?

Answer 21

This is a hand held navigation device that calculates angles and aids the surgeon (for unicompartmental knwee replacement).

Question 22

What is the aim of the intelligent knee implant ? (future project).

Answer 22

It is supposed to be a post operative device to monitor the implant with a remote. It take many measurement (implant position, material wear, osteolysis, heat, synovial viscosity….). It can be used for individual rehabilitation and prevention of long term pain.

measurement; pressure, chemical, temperature, joint movement (hall snesors), accelerometers, fluidic sensors.