Comparison of Total Knee Arthroplasty With Highly Congruent Anterior-stabilized Bearings versus a Cruciate-retaining Design

Abstract

Background The use of a highly conforming, anteriorstabilized bearing has been associated with clinical success in a limited number of studies. Questions/purposes We compared Knee Society scores, radiographic results, complication rates, and revision rates with the use of anterior-stabilized bearings compared with cruciate-retaining (CR) bearings. Methods A series of 382 patients with 468 primary total knee arthroplasties (TKAs) between 2003 and 2008 with minimum 2-year followup were reviewed. Anterior-stabilized bearings comprised 49% (n = 228) of the sample and CR bearings consisted of 51% (n = 240). The decision to use an anterior-stabilized bearing was based on integrity of the posterior cruciate ligament (PCL) intraoperatively or after sacrifice of the PCL to achieve soft tissue balance. The tibial and femoral component designs were the same regardless of bearing choice. Outcomes were measured with Knee Society scores, complications, revision TKA, and survival.Radiographs were analyzed for component alignment and evidence of loosening. Results There was no difference in Knee Society knee scores, radiographic alignment, component loosening, manipulation rate, major complications, or time to revision for patients between the two groups. However, the CR group had significantly more revisions than the anteriorstabilized group (21 CR [1.5%] versus seven anteriorstabilized [4.6%], p = 0.03) at a minimum followup of 5 months (mean, 42 months; range, 5-181 months). Conclusions The use of a highly congruent anteriorstabilized bearing for PCL substitution has comparable clinical and radiographic results to traditional CR TKA. These results suggest that this approach is an effective method to achieve stability without the PCL in primary TKA. Level of Evidence Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Outcomes of Posterior-Stabilized Compared with Cruciate-Retaining Total Knee Arthroplasty

“…Even though a statistically significant difference in ROM between PS and CR groups was detected, both the underreporting of results and the difference in follow-up times may influence our results. For example, there were differences in the definition of postoperative, most reporting at 2 years 5,8,19,23,28,30,32,33,36,38,40,42,43,45 and some at 5 years. 2,3,9,14,17 Also, it is difficult to know at what time assessment was undertaken postoperatively for those who did not clarify their methods of follow-up.…”

“…Complications were reported in only 17 of the 37 studies (45.9%). 3,[5][6][7]14,19,20,22,28,30,32,33,[35][36][37]44,45 There was an overall complication rate of 3.9% (213 complications in 5,407 knees). The meta-analysis 3,6,20,22,29,35,45 showed that no statistical difference was found between the two procedures (95% CI, 0.78-2.31; p ¼ 0.29).…”

Higher Frequency of Reoperation With a New Bicruciate-retaining Total Knee Arthroplasty

“…The remainder was performed with anterior-stabilizing or more constrained designs. Indications for performing a more constrained design were based on the integrity of the posterior cruciate ligament (PCL), severe deformity, or ligamentous deficiencies as we have previously described [19]. Only the CR TKAs were used as the control group in an effort to minimize confounding variables.…”

Partial versus Intact Posterior Cruciate Ligament‐retaining Total Knee Arthroplasty: A Comparative Study of Early Clinical Outcomes

“…The precise role of the posterior cruciate ligament (PCL) in CR TKA is unclear; however, most researchers believe that retaining the PCL greatly increases dynamic knee stability and retains femoral rollback during flexion and extension of the knee. Unlike with posterior stabilized TKA, the difficulty associated with performing CR TKA is how to achieve optimal PCL strain when balancing knee flexion and extension.…”