Histologic examination of tissues adjacent to a joint prosthesis may show a number of changes that can be described in a semiquantitative manner.
Parameters:
(1) histiocytes with phagocytosed material
(2) necrosis (total diameter in mm)
(3) globules of polymethylmethacrylate
(4) histiocytes containing metal particles (as wear product from metal-on-metal prosthesis)
(5) plastic particles (as wear product with plastic liner)
(6) bone chips
(7) neutrophils
(8) lymphocytes
|
Histiocytes |
Term |
|
none or isolated histiocytes |
none |
|
occasional histiocytes showing phagocytosed particles, some may be perivascular |
few |
|
numerous macrophages containing phagocytosed particles |
many |
|
histiocytes loaded with particles with foreign body giant cells |
abundant |
|
histiocytes overloaded with particles and diffuse foreign body granulomas |
excessive |
|
Necrosis |
Term |
|
none |
0 |
|
1 to 2 mm per slide |
1+ |
|
3 to 9 mm per slide |
2+ |
|
>= 10 mm |
3+ |
|
Methacrylate Globules per LPF (4 x objective) |
Term |
|
none |
0 |
|
1 to 3 |
1+ |
|
4 to 6 |
2+ |
|
> 7 |
3+ |
|
Bone Chips per LPF (4x objective) |
Term |
|
none |
0 |
|
1 to 5 |
1+ |
|
6 to 10 |
2+ |
|
> 10 |
3+ |
|
Histiocytes with Metal Particles |
Term |
|
none |
none |
|
slate blue with few particles |
few |
|
isolated black specks in cytoplasm |
dusty |
|
diffuse black cytoplasmic debris |
jet black |
where:
• The fibrous tissue around a metal-to-metal prosthesis may be grossly black in color.
|
Neutrophils (40x objective) |
Term |
|
0 |
none |
|
1 to 4 |
low grade inflammation |
|
5 |
high grade inflammation |
|
Lymphocytes (40x objective) |
Perivascular Lymphoid Aggregates (4x objective) |
Term |
|
<= 10 |
none |
none |
|
11 to 30 |
1 or 2 |
few |
|
31 to 50 |
3 to 6 |
many |
|
51 to 100 |
7 to 10 |
abundant |
|
> 100 |
> 10 |
excessive |
Specialty: Surgery, orthopedic
