1. 
   
2. In addition to wear debris generated a! the articular surfaces, backsid wear of modular libial polyethylene inserts has been 'implicated .; another source of debris (l^;ig. 24) (52).
4. 
6. Fig. (24) The backside surfaces of two retrieved specimens, a: This iiL'u:.-t (cightv-foiir months in situ) lias four distinct po/yct/iy'ene protrusions (arrows) with wear-through on tin: medial edge, b: This insert (cightv-two mouths in situ) shows wear predominantly on the medial side with polyethylene also protruding over the peripheral medial edge (53).
8. With backside wear, debris can access the periprosthetic interface
10. through screw-holes (72).
12. 2-Polyethylene thickness:
14. Thicker polyethylene provide more cushioning and lower stresses in the polyethylene than do thinner ones (72),.
16. On the basis of retrieval analyses and biomechariical studies of total knee components, a minimum thickness between 6 and \Z mm has been recommended in order to minimize stresses in the polyethylene (76).
18.  
20. 3-Soft tissue stability:
21. Ligament iaxity following a knee arthroplasty may lead to. subluxation of the joint and exacerbate wear, particularly when a flat tibial insert has been used (7).