Diagnosis and Management of the Stiff Total Knee Arthroplasty.

The stiff total knee arthroplasty (TKA) remains a major driver of dissatisfaction after primary implantation. Persisting myofibroblasts and a transforming growth factor-beta (TGF-β)-driven scar matrix underlies painful limitations in flexion/extension, either independent of or in addition to mechanical problems. A pragmatic diagnostic pathway includes structured history and examination, conventional radiographs, mandatory exclusion of periprosthetic joint infection, and targeted three-dimensional computed tomography (3D-CT) and single-photon emission computed tomography (SPECT-CT) for malposition/overstuffing; metal artifact reduction sequence MRI (MARS-MRI) supports soft-tissue-predominant pathology. Management is time-critical: early multimodal, opioid-sparing analgesia, strict oedema control, and pain-adapted physiotherapy; if flexion remains < 90-95° by week 6-8, manipulation under anaesthesia (MUA) (ideally ≤ 12 weeks) with immediate remobilization is indicated. Persistent adhesions are treated arthroscopically or openly; mechanical causes or failure warrant revision, including rotating-hinge strategies in selected cases. Early risk stratification, a stepwise algorithm, and tightly controlled rehabilitation stabilize range-of-motion gains and reduce reinterventions, although patient-reported outcomes may remain limited.