Subsidence Pattern of Charnley Cemented Femoral Revisions with Impacted Morcelised Bone After a Follow-up of Two to Twelve Years

We quantified the subsidence in 56 of 59 consecutive Charnley femoral revisions with impacted morcelised bone, after 57 months of follow-up (range 48–144). Subsidence was measured on AP radiographs obtained at regular intervals. Subsidence was analysed together with the development of radiographic loosening or need for re-revision subsidence. During the first two years it was compared with that of 50 Charnley primary arthroplasties. In forty-five revisions no subsidence was detected, and 11 had subsided an average of 6 millimeters (range 2–20). Among 52 successful revisions, 45 had no subsidence detected and 7 subsided less than 5 millimeters (average 2.42; range 2–4). All 4 failed revisions subsided (average: 12 millimeters; range 2–20). The difference between successful and failed revisions was significant (p=0.009). At 2 years of follow-up, 9 revisions and 2 primary arthroplasties had subsidence detected (p=0.14). Subsidence detected after the second year was observed in all failed revisions and in only one successful. Subsidence in successful Charnley revisions is restricted to less than 5 millimeters and occurs during the first two postoperative years. The different subsidence pattern between revision and primary arthroplasties suggests that limited subsidence of the grafts occurs, predominantly during the first two years.