LIBRO DE OBSEQUIO SORPRESA 1 BREAST CANCER

8
Histological Diagnosis of Implant-Associated Pathologies
. . Fig. 5 SLIM type IV. Neo-synovial membrane shows loss of lining cell layer, focal hemorrhage, and florid
reactive fibrovascular proliferation (H&E, ×200)
2.7 Prosthesis-Associated Arthrofibrosis (Type V)
Prosthesis-associated arthrofibrosis is clinically associated with a reduced range of motion
and/or painful restriction of the range of motion with the knee joint predominantly affected.
The prevalence of arthrofibrosis after knee arthroplasty has been reported to be as high as
5–10% [11], [12] and its pathogenesis is still not well understood. Attention is increasingly
shifting to the histological, biochemical, and molecular processes underlying arthro fibrosis
rather than the previous descriptive model of “adhesions.” The cellular and cytokine-based
pathogenesis model can offer alternative new therapeutic options in the future, either for
prevention or for local control of this complication [13].
Prosthesis-associated arthrofibrosis consists of a pronounced peri-implant or intraarticular
fibrous reaction after surgery. The extent of the fibroblastic reaction with ensuing
fibrosis of the periprosthetic tissue is variable. The histological diagnosis involves a classification
into three grades (mild, moderate, marked) that is based on the density of
the fibroblasts (. Fig. 6). A correlation between the grading system and the number of
β-catenin-positive fibroblasts per high-power field (HPF) at ×400 magnification has
been reported with a threshold of ≥ 20 β-catenin-positive fibroblasts per HPF providing
a diagnostic sensitivity of 72% and a specificity of 87% [14]. Synovial fibroblasts in arthrofibrosis
have also been recently found expressing high fibroblast/myofibroblast transition
and xylosyltransferase-I, alpha-SMA protein, collagen type III-alpha-1, and ACTA2
mRNA [13].