Severe Quadriceps Heterotopic Ossification after Knee Revision Arthroplasty in a 42-Year-Old Suffering from Rheumatoid Arthritis: A Case Report

Background: Heterotopic Ossification (HO) of the knee is most commonly formed anteriorly to the distal femoral shaft in the quadriceps expansion. Although the incidence of severe HO with large dimensions affecting the knee and resulting in severe consequences is extremely rare, these cases are extremely difficult to prevent and have severe clinical limitations for the patient. Aim: The purpose of this study was to present and explore HO formation after Total Knee Arthroplasty (TKA). Conclusions: It is crucial to perform a stratification of patients for the risk of HO formation after TKA and to gain a better understanding of the fundamental role of post-operative treatments. In severe HO, surgery should be considered following appropriate investigations and should only be considered when the HO has fully matured. In comparison to Total Hip Arthroplasty (THA), HO formation after TKA is less frequent and underexplored. Therefore, further studies are required. This case report can represent a protocol for the treatment of clinically relevant HO in the knee after TKA.