Posterior dislocation after posterior stabilization TKA.

Posterior dislocation after primary total knee arthroplasty is a rare but serious complication. The authors described an 85-year-old man receiving bilateral total knee arthroplasty, which achieved good flexion arc immediately. Posterior dislocation occurred on right knee one month after operation, which was treated by close reduction and casting. Dislocation recurred in combination with infection. The mechanism of dislocation was checked under vision when performing open reduction and debridement. The tibial spine escaped from femoral cam in slight flexion and external rotation due to flexion laxity and biceps tethering. On the way to pursuit higher flexion angle, which is beyond the ordinary daily demand, excessive soft tissue release and bone resection seems to b e compromised. Flexion instability alsooccurs out of purpose, accompanied with increased risk of dislocation.