Revision Knee Replacement
Painful knee arthroplasty
Painful knee arthroplasty presents a major diagnostic challenge. In certain cases even a careful history-taking, meticulous clinical examination and numerous investigations may not help in reaching a diagnosis. Infection is particularly difficult to diagnose. To date there is no single preoperative investigation that can reliably diagnose an infection. Our inability to diagnose subclinical infection before revision surgery is still a major concern.
Possible causes of painful knee arthroplasty
● Aseptic loosening
● Patellar pain or dislocation
● Extensor mechanism rupture
● Incompetent medial collateral ligament
● Periprosthetic fracture
● Implant breakage
● Complex regional pain syndrome
● Hip or spine pathology (referred pain)
● Unexplained pain (1/300)
Date of index operation, postoperative pain relief/problems, wound leak, wound infection (and need for antibiotics), pain at rest, mechanical pain, stair climbing and descent, any injuries, medical problems, especially diabetes and rheumatoid arthritis.
Limp, walking aid, leg alignment, patellar alignment/tracking/ tenderness, inflammation, effusion, quadriceps tone, CRPS (RSD) signs, joint tenderness localized/generalized, ROM active/passive, laxity in sagittal/coronal plane and finally assess the hip, spine and foot.
Plain weight-bearing x-ray, bloods (including WCC, ESR and CRP – IL-6 (expensive) in specialist units), bone scan (not helpful until at least year after the index procedure), white cell-labelled bone scan, knee aspiration, fluoroscopic alignment check, CT scan to check rotation and long leg films to assess the overall alignment. SPECT bone scan and SPECT-CT has also been a novel imaging option to de