Heterotopic ossification within an arthroscopic portal after uneventful partial meniscectomy.

We report the case of a 44-year-old man who underwent a partial medial meniscectomy for a meniscal tear whose postoperative course was complicated by the development of heterotopic ossification (HO) within the medial arthroscopic portal. Following a routine initial procedure, the patient presented with ongoing pain and a palpable, painful lump around the previous medial arthroscopy portal. Plain radiographs and MRI were suggestive of a bony structure within the soft tissues. Histopathological examination at repeat arthroscopy confirmed osseous tissue consistent with HO. Recovery after the second procedure was rapid and resulted in normal knee function and complete pain relief. HO within an arthroscopy portal is a rare complication following arthroscopic partial meniscectomy in the knee and has not previously been described in the literature.