Appeal No. 2002-2198 Page 5
Application No. 09/408,409
the bone preparation. Thus, wear debris is substantially prevented from migrating
toward the interfaces between the implant components and their associated bone
tissues. Accordingly, wear debris promoted osteolysis and its resulting trauma, pain
and potential for implant loosening is reduced. The capsule 82 further operates to
substantially prevent metal and cement debris 84, remaining at the interfaces between
the components and their associated bones, from migrating into the capsule and
toward the articulating surfaces of the components.
Kwong states (column 6, lines 35-50) that this is in marked contrast to the prior
art prosthetic hip joint assembly shown in Figure 5, which shows the formation of a
normal capsule 85 of fibrous tissue. Since the prior art acetabular and femoral
components lack the surface treatments of Kwong's invention, the fibrous tissue tends
to attach within the boundary of the bone preparation circumscribing the acetabular
component and the femoral component. Consequently, any wear debris 86 from the
bearing insert can easily migrate toward the preparation boundary into the interfaces
between the implants and adjacent bone producing osteolysis and eventual implant
loosening. Moreover, metal and cement debris 88, remaining at the interfaces between
the components and their associated bones, can easily migrate into the capsule and
toward the articulating surfaces of the components and cause premature bearing wear
and additional wear debris.
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