Condylar constrained and rotating hinged implants in revision knee arthroplasty show similar survivorship and clinical outcome: a systematic review and meta-analysis

Purpose In revision total knee arthroplasty (TKA) ligament instability and bone defects might require more constraint implants such as a condylar constrained knee (CCK) or rotating hinged knee (RHK). When both implants are suitable, the choice remains controversial. The purpose of this systematic review and meta-analysis was to compare the survivorship and clinical outcome between CCK and RHK in revision TKA. Methods Systematic literature research was performed. Studies analysing the clinical outcome and/or survivorship of CCK and/or RHK in revision TKA were included. Clinical outcomes included the Knee Society Score, both clinical (KSCS) and functional (KSFS), range of motion (ROM) and reoperations. Survival was defined as the time free from removal or revision of the femoral and/or tibial component. Results A total of 40 articles analysing 4.555 knees were included. Survival did not differ between RHK and CCK implants ( p = 0.6058), with, respectively, 91.6% and 89.8% survival after 5 years. Postoperative KSCS and KSFS were, respectively, 79.2 (SD 10.7) and 61.1 (SD 21.8) for the CCK group. Similar scores were noted for the RHK group with a KSCS of 80.2 (SD 14.1) and KSFS of 58.5 (SD 17.3). Postoperative ROM was similar for CCK (105.3°, SD 17.1°) and RHK patients (104.1°, SD 16.9°). Conclusion This meta-analysis revealed that both survivorship and clinical outcome are similar for CCK and RHK patients for whom both designs are technically suitable and indicated. Level of evidence IV.