Basic most important tips and tricks for treatment of the non-infected unhappy total knee arthroplasty - what to do?
Background: Approximately 10% to 30% of patients experience persistent pain or dissatisfaction following primary total knee arthroplasty (TKA), with global registries reporting revision rates between 3% and 12%. Common failure modes include aseptic loosening, infection, instability, and malalignment. Addressing these complications requires a systematic approach to differentiate between intra-articular and extra-articular etiologies.
Objective: This article delineates a standardized diagnostic algorithm and therapeutic framework for the management of the painful or failing TKA, emphasizing the "puzzle concept" to correlate clinical symptoms with objective pathological findings.
Key Points: A comprehensive diagnostic work-up is essential, incorporating detailed medical history to identify specific pain patterns, such as instability-related lancinating pain or patellofemoral-related pain during stair descent. Radiographic evaluation must include weight-bearing, patellar skyline, and whole-leg views to assess component positioning and mechanical axes. Advanced imaging, specifically combined SPECT/CT, provides integrated mechanical, structural, and biological data for precise component measurement in three planes. Differential diagnoses should consider periprosthetic joint infection, metal hypersensitivity, and nerve entrapment, such as the infrapatellar branch of the saphenous nerve. Surgical intervention is reserved for cases with a confirmed mechanical or biological cause. Revision strategies utilize zonal fixation across the joint, metaphyseal, and diaphyseal regions, often requiring increased prosthetic constraint ranging from posterior-stabilized to hinged designs.
Conclusion: Successful revision TKA depends on the precise identification of failure modes through a standardized multidisciplinary algorithm. Surgical intervention should only be pursued when objective diagnostic findings align with patient symptoms and expectations.
