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Histological features of pseudotumor-like tissues from metal-on-metal hips.

Campbell P, Ebramzadeh E, Nelson S, Takamura K, De Smet K, Amstutz HC - Clin. Orthop. Relat. Res. (2010)

Bottom Line: A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization.Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction.Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes.

View Article: PubMed Central - PubMed

Affiliation: J Vernon Luck Sr MD Orthopaedic Research Center, Orthopaedic Hospital/UCLA, 2400 S Flower Street, Los Angeles, CA 90007, USA. campbell@laoh.ucla.edu

ABSTRACT

Background: Pseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity.

Questions/purposes: We therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes.

Methods: Tissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups.

Results: The tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group.

Conclusions: Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes.

Clinical relevance: Painful hips with periprosthetic masses may be caused by high wear, but if this can be ruled out, metal hypersensitivity should be considered.

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Related in: MedlinePlus

An enlarged fluid-filled bursa excised from the hip of a male patient during revision surgery for acetabular malpositioning 13 months after metal-on-metal hip resurfacing arthroplasty is shown. There is light gray discoloration and the wear measurement of the explanted component showed an annual femoral wear rate of 12.8 μm.
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Fig1: An enlarged fluid-filled bursa excised from the hip of a male patient during revision surgery for acetabular malpositioning 13 months after metal-on-metal hip resurfacing arthroplasty is shown. There is light gray discoloration and the wear measurement of the explanted component showed an annual femoral wear rate of 12.8 μm.

Mentions: Twenty-two of the tissue samples submitted were large, smooth-walled sacs, and some of the tissues were clearly metal-stained (Fig. 1). All of the tissues were fixed in 10% formalin immediately after removal. They were weighed, measured, photographed, and their gross appearance was noted. From two to five tissue samples from several sites, especially if there were variations in color or texture of the specimen, were embedded in paraffin blocks for routine sectioning and staining with hematoxylin and eosin. Three of us (PC, SN, KT) examined at least six tissue specimens per case semiquantitatively for lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles using the method of Doorn et al. [11], i.e., where a zero to 3 plus score is given as features of interest become more numerous in a high power 40× microscopic field of view. This type of method reportedly has an interobserver agreement level of 0.91 [3].Fig. 1


Histological features of pseudotumor-like tissues from metal-on-metal hips.

Campbell P, Ebramzadeh E, Nelson S, Takamura K, De Smet K, Amstutz HC - Clin. Orthop. Relat. Res. (2010)

An enlarged fluid-filled bursa excised from the hip of a male patient during revision surgery for acetabular malpositioning 13 months after metal-on-metal hip resurfacing arthroplasty is shown. There is light gray discoloration and the wear measurement of the explanted component showed an annual femoral wear rate of 12.8 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2914255&req=5

Fig1: An enlarged fluid-filled bursa excised from the hip of a male patient during revision surgery for acetabular malpositioning 13 months after metal-on-metal hip resurfacing arthroplasty is shown. There is light gray discoloration and the wear measurement of the explanted component showed an annual femoral wear rate of 12.8 μm.
Mentions: Twenty-two of the tissue samples submitted were large, smooth-walled sacs, and some of the tissues were clearly metal-stained (Fig. 1). All of the tissues were fixed in 10% formalin immediately after removal. They were weighed, measured, photographed, and their gross appearance was noted. From two to five tissue samples from several sites, especially if there were variations in color or texture of the specimen, were embedded in paraffin blocks for routine sectioning and staining with hematoxylin and eosin. Three of us (PC, SN, KT) examined at least six tissue specimens per case semiquantitatively for lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles using the method of Doorn et al. [11], i.e., where a zero to 3 plus score is given as features of interest become more numerous in a high power 40× microscopic field of view. This type of method reportedly has an interobserver agreement level of 0.91 [3].Fig. 1

Bottom Line: A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization.Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction.Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes.

View Article: PubMed Central - PubMed

Affiliation: J Vernon Luck Sr MD Orthopaedic Research Center, Orthopaedic Hospital/UCLA, 2400 S Flower Street, Los Angeles, CA 90007, USA. campbell@laoh.ucla.edu

ABSTRACT

Background: Pseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity.

Questions/purposes: We therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes.

Methods: Tissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups.

Results: The tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group.

Conclusions: Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes.

Clinical relevance: Painful hips with periprosthetic masses may be caused by high wear, but if this can be ruled out, metal hypersensitivity should be considered.

Show MeSH
Related in: MedlinePlus