Similar outcome after retention or sacrifice of the posterior cruciate ligament in total knee arthroplasty

Abstract

Background and purpose: To retain or to sacrifice the posterior cruciate ligament (PCL) in total knee arthroplasty (TKA) remains a matter of discussion. In this systematic review, we wanted to find differences in functional and clinical outcome between the 2 methods.

Methods: We conducted a systematic review and meta-analysis including all randomized controlled trials (RCTs) and quasi-RCTs that have compared PCL retention with PCL sacrifice in TKA with a minimum of 1-year follow-up. Primary outcome was range of motion. Secondary outcomes were knee pain and clinical scoring systems that were preferably validated. Quality of evidence was graded using the GRADE approach. All outcomes available for data pooling were used for meta-analysis.

Results: 20 studies involving 1,877 patients and 2,347 knees were included. In meta-analysis, the postoperative flexion angle had a mean difference of 2 degrees (95% CI: 0.23-4.0; p = 0.03) and the KSS functional score was 2.4 points higher in favor of PCL sacrifice (95% CI: 0.41-4.3; p = 0.02). There were no statistically significant differences regarding other measured clinical outcomes such as WOMAC, KSS pain, clinical and overall score, HSS score, SF-12, radiolucencies, femoro-tibial angle, and tibial slope. The quality of the studies varied considerably. Risk of bias in most studies was unclear; 5 were judged to have a low risk of bias and 5 to have a high risk of bias.

Interpretation: We found no clinically relevant differences between retention and sacrifice of the PCL in TKA, in terms of functional and clinical outcomes. The quality of the studies ranged from moderate to low. Based on the current evidence, no recommendation can be made as to whether to retain or to sacrifice the PCL.

Figure 1.

Flow chart of study selection showing the process of article selection and the reasons for articles being excluded.

Figure 2.

Forest plots from meta-analysis. A. Knee flexion from all PCL-sacrificing and PCL-retaining TKAs. Shows homogeneous results favoring PCL sacrifice with 2.1 degrees better flexion angle. B. Knee flexion from PCL-retaining TKA design versus posterior-stabilized TKA design. Shows homogeneous results favoring PCL sacrifice, with 2.8-degrees better flexion angle. C. Knee Society functional score from all PCL-sacrificing and PCL retaining TKAs. Shows homogeneous results favoring PCL sacrifice, with 2.4 more points in mean difference. D. WOMAC score from all PCL-sacrificing and PCL-retaining TKAs. Shows homogeneous results without any significant differences (0.78 points favoring PCL retention).