Management of instability after primary total knee arthroplasty: an evidence-based review

Background Instability is one of the most common reasons for revision after a total knee replacement. It accounts for 17.4% of all single-stage revision procedures performed in the UK National Joint Registry. Through a careful patient evaluation, physical assessment and review of investigations one can identify the likely type of instability. Aims To critically examine the different types of instability, their presentation and evidence-based management options. Method A comprehensive literature search was conducted to identify articles relevant to the aetiology and management of instability in total knee replacements. Results Instability should be categorised as isolated or global and then, as flexion, mid-flexion, extension or recurvatum types. By identifying the aetiology of instability one can correctly restore balance and stability. Conclusion With careful judgement and meticulous surgical planning, instability can be addressed and revision surgery can provide patients with successful outcomes.