Abstract
Introduction: Early non progressive horizontal RLLs (< 2mm) under the tibial component following cemented TKR have been noted to be due to poor cement injection into cancellous bone. They may facilitate the entry of joint fluid and wear debris into the interface, which may proceed to ballooning osteolysis. At present, there is no consensus on the preferred cementing technique (single mix versus dual mix cementation) in TKR.
Purposes of the study: To assess RLLs in immediate postoperative radiographs in cemented TKRs at the cement-bone and cement-implant interface.
To compare the RLLs following single mix and dual mix cementation techniques.
Study Design: Prospective, consecutive radiographic analysis.
Material and Methods: 53 consecutive cemented TKRs in 39 patients (12: 27, F: M) with mean age of 72.5 years (range 50–90 y) who were operated on between 2001 to 2004 by the senior author (NMG). 27 had single mix and 26 had double mix cementation. Immediate postoperative radiographic assessment (AP and LAT standing view) was blinded for single mix versus dual mix cementation. All the radiographs were independently assessed by two of the authors for the presence of RLLs using the zonal pattern of the Knee Society scoring system. We have evaluated the RLLs in the cement-implant interface in a similar manner as described for the bone-cement interface.
Results: Most common TKR used was the Maxim (31) followed by the PFC (9). 29(54.7%) TKRs had RLLs (11in single mix : 18 in dual mix). There were more RLLs at the Cement-implant interface (29), than the bone-cement interface (10). In AP view, Zones 1(medial) and 4 (lateral) were the common sites for RLLs in both groups (< 2mm). In Lateral view, Zone 1 (Anterior) followed by Zone 2 (Posterior) were the common sites of RLLs (< 2mm). In AP view, there was no significant difference in the number of RLLs (Zone 4) between the two groups. The total number of RLLs in all zones (Zone 1–4) was significantly low in the single mix group (p< 0.05). There was no difference between the two groups in the lateral view.
Conclusions: Single mix cementation technique reduces the incidence of RLLs in the immediate postoperative radiographs following cemented TKRs.
Honorary Secretary – Mr Roger Smith. Correspondence should be addressed to BASK at the Royal College of Surgeons, 35 - 43 Lincoln’s Inn Fields, London WC2A 3PN
References:
Smith S, Naima VSN, Freeman MAR; The Natural History of Tibial Radiolucent Lines in a Proximally Cemented Stemmed Total Knee Arthroplasty. J. Arthroplasty, 14(1),3–9, 1999. Google Scholar
