Total knee replacement in triple deformity with posterior subluxation of the knee joint.

Dislocation or subluxation following total knee arthroplasty has been extensively reported, but vice versa that is total knee replacement for subluxed or dislocated knee has not been published. Triple deformity of knee that is flexion, external rotation, valgus at knee associated with posterior subluxation of tibia occurs in rheumatoid arthritis, advanced tubercular arthritis and neglected posttraumatic residual dislocated knee. A 50 year old female with seropositive rheumatoid arthritis had the above disabling deformity in left lower limb and varus with medial tibial thrust in the other. Bilateral total knee arthroplasty was planned. Conservative method of reduction of left knee posterior subluxation preoperatively by 90-90 skeletal traction failed; hence patient was subjected to a staged bilateral total knee replacement using an innovative technique. The most difficult and determining initial surgical step of knee replacement in such dislocated/subluxed knee is reduction of posterior subluxation and gaining flexion at knee, as only after gaining flexion and reducing dislocated tibia, will we be able to do knee arthroplasty in triple deformity of knee. These knees are grossly unstable as most of the capsule-ligamentous structures are attritioned/non-existent. So, a fine balance of bone cuts and soft-tissue release needs to be done in a sequential manner to fine tune valgus and posterior subluxation correction without jeoparadising neurovascular structures. After 3 years of knee arthroplasty the patient has painless, stable knee with good range of motion and is able to do all her activities, of living in a hilly terrain.