Radiolucent lines below the tibial component of a total knee replacement (TKR) - a comparison between single- and two-stage cementation techniques

Early non-progressive horizontal radiolucent lines (RLLs) (< 2 mm) under the tibial component following cemented total knee replacement (TKR) are considered to result from poor cement injection into cancellous bone. These RLLs may facilitate the entry of joint fluid and wear debris into the interface, which may proceed to ballooning osteolysis. There is currently no consensus on the preferred cementing technique (single- versus two-stage cementation) in TKR. We have prospectively analysed postoperative radiographs in 50 consecutive TKRs to compare the RLLs following single- (25 TKRs) and two-stage (25 TKRs) cementation techniques. Of the TKR radiographs studied, 26 (52%) had RLLs; nine (36%) of these were single-stage TKRs, and 17 (68%) were two-stage TKRs. This study demonstrates that single-stage cementing may be superior to the two-stage technique in terms of avoiding RLLs in immediate postoperative TKRs.