A comparative study of flat surface design and medial pivot design in posterior cruciate-retaining total knee arthroplasty: a matched pair cohort study of two years

Abstract

BackgroundComponent design is one of the contributory factors affecting the postoperative flexion angle. The purpose of this study was to compare short-term outcomes of flat surface and medial pivot designs in posterior cruciate-retaining (CR) total knee arthroplasty (TKA).MethodsA retrospective, case-control, and observational cohort study consisted of matched-pairs of the flat surface design (Hi-Tech Knee II) and the medial pivot design (FINE Knee) in CR-TKA with a two-year follow-up period.ResultsHi-Tech Knee II and FINE knee groups each included 7 males and 38 females. Surgical time was significantly shorter in the FINE Knee group than in the Hi-Tech Knee II group (104.8 min versus 154.9 min, p = 0.001). Estimated total blood loss was significantly lower in the FINE Knee group than in the Hi-Tech Knee II group (654 ml versus 1158 ml, p = 0.001). The postoperative flexion angle was significantly better in the FINE Knee group than in the Hi-Tech Knee II group (119.3 degrees versus 112.5 degrees), and was positively correlated with the preoperative flexion angle. Postoperative Knee Society scores were significantly better in the FINE Knee group than in the Hi-Tech Knee II group (93.0 points versus 85.0 points, p = 0.001), especially for postoperative pain relief (46.0 points versus 39.0 points out of 50, p = 0.001). Complications were not observed in either group over a two-year follow-up period.ConclusionThe short-term outcome of the medial pivot design used in CR-TKA was more favorable than the flat surface design, especially for surgical time, estimated total blood loss, postoperative flexion angle, and knee pain.Electronic supplementary materialThe online version of this article (10.1186/s12891-018-2138-z) contains supplementary material, which is available to authorized users.

Lateral Shift of the Femoral Condyle After Total Knee Arthroplasty: Simulation Using 2d-templates of the Medial Pivot Design on Knee Radiographs of Young Japanese Patients

“…Uvehammer et al demonstrated that the Hospital for Special Surgery knee score and the patients' opinion based on their preoperative expectations were not very different [20]. On the other hand, a two-year matched pair cohort study demonstrated that the clinical outcomes of the medial pivot design used in CR-TKA were more favorable than those of the at surface design [21]. It is di cult to draw conclusions about which is better, but the absence of signi cant differences in clinical scores shown by Uvehammer et al suggests that even the at surface allows medial pivot motion when appropriate ligament balances are achieved.…”

“…Those are concerns in TKA with the medial pivot design. Clinical studies comparing at vs. concave inserts have been made and reported [20,21]. Uvehammer et al demonstrated that the Hospital for Special Surgery knee score and the patients' opinion based on their preoperative expectations were not very different [20].…”

Early Outcomes of Medial Pivot Total Knee Arthroplasty Compared to Posterior-Stabilized Design: A Randomized Controlled Trial

“…As far as MP total knee arthroplasty is concerned, there are limited studies comparing its outcomes with those of other implant designs (Table 3). 5,13,[18][19][20][21][22][23][24][25] To date, there is only one randomized study by Hossain et al, 5) which has compared outcomes of an MP knee to a fixed-bearing multi-radius PS implant. There are three other randomized controlled trials (RCTs), which have compared an MP design to a mobile PS knee: an ultra-congruent rotating platform knee in studies by Kim et al 18) and Kim et al 19) and a single radius knee in a study by Benjamin et al 20) There are a few more matched pair studies and case series, which have looked at outcomes of the MP design.…”

Clinical radiographic outcomes and survivorship of medial pivot design total knee arthroplasty: a systematic review of the literature

“…Eight studies [19,23,27,35,39,41,43,48] Minor (< 2 mm) and non-progressive femoral radiolucent lines were found in 146 (7.5%) knees on the femoral side and in 175 (9.0%) cases on the tibial side. Major or progressive femoral RLL were reported in 11 (0.5%) cases.…”