A 34-year-old male patient presented with right-sided posteromedial knee pain following an attempted tackle during a soccer match. MRI revealed that the semitendinosus (ST) tendon had completely avulsed from its distal insertion site. The patient was initially managed conservatively but eventually required surgery due to ongoing posteromedial knee pain. Surgical management was achieved through tenodesis of ST to gracilis. Postsurgery, the posteromedial knee pain had been alleviated, and following physiotherapy the patient regained a good range of motion.

This report presents the case of a 57-year-old male patient who underwent a total knee arthroplasty (TKA) using an uncemented Triathlon system and subsequently went on to develop a prosthetic joint infection (PJI) with eventual polyethylene insert dislocation. This report presents the clinical, radiological and surgical findings of the insert dislocation on the background of PJI and explores this rare complication of TKA by providing a summary of the literature on this topic.