Aseptic loosening of a cemented total hip replacement is characterised by radiolucent lines at the cement-bone interface. The zone of the acetabular component most relevant to early loosening according to the DeLee and Charnley classification is:
- A Zone II (medial dome) ✓
- B Zone I (superolateral)
- C Zone III (inferolateral)
- D All zones are equally significant
Correct answer: A. Zone II (medial dome)
Explanation
The DeLee and Charnley classification divides the acetabulum into three zones: Zone I (superolateral), Zone II (medial), and Zone III (inferior/inferomedial). Radiolucency in Zone II (the medial dome) is particularly significant because it implies loss of support at the weight-bearing dome, which is associated with rapid progression to clinical loosening. Isolated Zone I or III radiolucency may be benign, but medial dome lucency indicates impending failure.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.