Fatigue failure of the femoral component of a total knee arthroplasty: a case report and review of the literature

Introduction: Reports of fatigue failure of the femoral component of a total knee arthroplasty (TKA) is scanty in the literature. As a result, there are no clearly defined risk factors to aid us in predicting fatigue failure of an implant. Furthermore, these patients may present with non-specific knee pain, which may or may not be well tolerated, depending on the stability of the implant. We report a case of fatigue failure of a poorly cemented femoral component of a TKA in a 72-year-old female, approximately seven years after the initial surgery. Case report: A 72-year-old female presented to our tertiary level arthroplasty unit with new-onset knee pain approximately seven years after undergoing a TKA at our unit. She reported hearing a crack six months earlier, while standing up from a seated position. She had initially presented to her local clinic, but the pathology was missed. She received revision surgery at our institution and was doing well at early follow-up. Discussion: We reviewed the literature on fatigue failure of femoral components in TKA in an attempt to define risk factors. We also summarised all cases of femoral component fatigue failure in the English literature. Conclusion: Although femoral component fatigue failure in TKA is rare, the majority of cases have attributed the failure to poor surgical technique. Despite this, certain implants have been failing more often than others, and proposed mechanisms for this exist. Orthopaedic surgeons need to be aware of which implant designs are prone to failure, as well as how meticulous surgical technique can reduce the chances of fatigue failure. Level of evidence: Level 5