arthroplasty
Aseptic Loosening of Total Hip Arthroplasty
advanced
6 min
20 marks
6 questions
Clinical Scenario
A 72-year-old male presents with progressive left groin and thigh pain 12 years after uncemented THA for osteoarthritis. Pain is activity-related with start-up pain and is now limiting walking to 100m. He denies fevers or systemic symptoms. CRP is 3 mg/L (normal). Radiographs show extensive osteolysis around both components.
AP pelvis radiograph showing left THA with progressive radiolucent lines around acetabular component (DeLee-Charnley zones 1-3), cup migration superolaterally, and femoral subsidence with cement mantle fracture. Gruen zone involvement visible.
Source: Metallosis after Exchange of the Femoral Head and Liner following Ceramic Acetabular Liner Dissociation • PMC5014961 • CC-BY
Questions
Question 1 (3 marks)
Describe the radiographic zones used to assess THA loosening and their clinical significance.
Question 2 (4 marks)
This patient has significant acetabular bone loss. Describe the Paprosky acetabular classification and how it guides reconstruction.
Question 3 (4 marks)
The femoral stem is loose with proximal bone loss. Describe the Paprosky femoral classification and reconstruction options.
Question 4 (3 marks)
What are the indications and technique for Extended Trochanteric Osteotomy (ETO)?
Question 5 (3 marks)
What factors determine the choice between cemented and uncemented revision components?
Question 6 (3 marks)
What preoperative planning is essential for complex revision THA?
Exam Day Cheat Sheet
Must Mention
- •EXCLUDE INFECTION before any aseptic revision
- •Paprosky classification guides reconstruction choice
- •Aim for 50-70% host bone contact for ingrowth
- •ETO for removal of well-fixed stems or cemented stems
- •CT essential for bone stock assessment
- •Have backup options available
Common Pitfalls
- •Revising without excluding infection
- •Underestimating bone loss on X-ray
- •Not having backup implant options
- •Inadequate preoperative planning
- •Missing pelvic discontinuity