Erratum to 'Unicondylar Knee Arthroplasty Following a Patellectomy' [Arthroplasty Today 6 (2020) 48-51].

[This corrects the article DOI: 10.1016/j.artd.2019.10.005.].

Unicondylar knee arthroplasty following a patellectomy.

We present a case of a 59-year-old woman with a history of a right-sided patellectomy. She presented with right-sided anteromedial osteoarthritis. A unicondylar knee arthroplasty was performed. In the literature, we found only a few similar cases, with varying results. The woman in this case showed excellent postoperative clinical results. We concluded that a patellectomy may not be a contraindication for unicondylar knee arthroplasty in patients with isolated medial compartment osteoarthritis.

Desmoid tumors display a strong immune infiltration at the tumor margins and no PD-L1-driven immune suppression.

Desmoid tumors (DTs) are local aggressive neoplasms, whose therapeutic approach has remained so far unsolved and in many instances controversial. Nowadays, immunotherapy appears to play a leading role in the treatment of various tumor types. Characterization of the tumor immune microenvironment (TME) and immune checkpoints can possibly help identify new immunotherapeutic targets for DTs. We performed immunohistochemistry (IHC) on 33 formalin-fixed paraffin-embedded (FFPE) tissue sections from DT samples to characterize the TME and the immune checkpoint expression profile. We stained for CD3, CD4, CD8, CD20, FoxP3, CD45RO, CD56, CD68, NKp46, granzyme B, CD27, CD70, PD1 and PD-L1. We investigated the expression of the markers in the tumoral stroma, as well as at the periphery of the tumor. We found that most of the tumors showed organization of lymphocytes into lymphoid aggregates at the periphery of the tumor, strongly resembling tertiary lymphoid organs (TLOs). The tumor expressed a significant number of memory T cells, both at the periphery and in the tumoral stroma. In the lymphoid aggregates, we also recognized a significant proportion of regulatory T cells. The immune checkpoint ligand PD-L1 was negative on the tumor cells in almost all samples. On the other hand, PD1 was partially expressed in lymphocytes at the periphery of the tumor. To conclude, we are the first to show that DTs display a strong immune infiltration at the tumor margins, with formation of lymphoid aggregates. Moreover, we demonstrated that there is no PD-L1-driven immune suppression present in the tumor cells.