Synopsis
Triage a painful hip or knee replacement into immediate mechanical emergency, infection and gradual failure pathways; use comparison imaging and disciplined sampling, and avoid revision without a specific diagnosis.
- For sudden deformity or loss of function, record neurovascular status and obtain AP and orthogonal radiographs before and after reduction; do not repeatedly manipulate a possible fracture.
- A first hip dislocation is reduced promptly with adequate sedation or anaesthesia, then assessed for fracture, component position, cause and stability; recurrent episodes need revision expertise.
- A painful replacement is not automatically loose or infected. Build a timeline of surgery, wound, pain-free interval, trauma, bacteraemia, antibiotics, mechanical symptoms and systemic features.
Key red flags
A shortened deformed limb, sudden inability to move after hip replacement or an abnormal radiograph indicates dislocation or fracture and requires urgent orthopaedic management.
Investigation priorities
Confirm dislocation, fracture and component position.
Management branches
Dislocation, fracture or abrupt component failure produces deformity or inability to load.
- Document distal neurovascular status, provide analgesia, protect the limb and obtain urgent full implant radiographs.
- Reduce a confirmed dislocation promptly with adequate relaxation and orthopaedic support; avoid force when fracture is possible.
Pain, drainage, sinus, effusion or systemic illness makes prosthetic infection plausible.
Key medicines
Analgesia and procedural sedation for dislocationGive titrated intravenous analgesia and procedural sedation or general anaesthesia under the emergency department and anaesthetic protocol, with continuous monitoring and personnel able to manage airway and fracture complications; no fixed drug combination replaces patient-specific assessment.
Empirical parenteral therapy for septic prosthetic-joint infectionAfter urgent blood cultures, give the full adult sepsis and prosthetic-joint-infection protocol regimen immediately; obtain deep samples at emergency drainage and narrow to organism, renal function and the selected implant operation.