Table 1.

Main causes of knee prosthesis instability (KPI)

Ligament imbalance

Component disalignment

Component failure

Implant design

Mediolateral instability

Bone loss from over resection of the distal femur

Bone loss from femoral or tibial component loosening

Soft tissue laxity of the medial and lateral collateral ligaments

Connective tissue disorders (rheumatoid arthritis or Ehlers–Danlos syndrome)

Inaccurate femoral or tibial bone resection

Collateral ligament imbalance (under release, over release, or traumatic disruption)