A
Cruciate-retaining (CR) knees with an asymmetric patellar dome
B
Mobile-bearing unicompartmental knee systems
C
Medial pivot total knee designs
D
Posterior-stabilized (PS) knees with a high intercondylar box
Explanation:Correct Option: D. Patellar clunk syndrome occurs when a fibrosynovial nodule forms at the superior pole of the patella. During active extension from a flexed position, this nodule catches in the intercondylar box of a posterior-stabilized (PS) femoral component, releasing with a palpable and audible 'clunk'. (Ref: Hozack et al., Clin Orthop Relat Res, 1989)