A Medial Congruent Polyethylene Offers Satisfactory Early Outcomes and Patient Satisfaction in Total Knee Arthroplasty

Abstract

Background Although a successful operation, almost 20% of patients are dissatisfied with total knee arthroplasty (TKA). The purpose of this retrospective cohort study was to see if a medial congruent (MC) polyethylene would offer satisfactory early outcomes and patient satisfaction after TKA. Methods We reviewed prospectively collected data on 327 TKAs using multiple bearings within the same implant system. Ninety-six received an MC bearing, 70 received a cruciate-retaining (CR) bearing, and 161 received a posterior-stabilized (PS) bearing. We evaluated the visual analog scale pain scores and range of motion (ROM) at 2 weeks, 6 weeks, 3 months, and 1 year; Patient-Reported Outcomes Measurement Information System (PROMIS-10) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 3 months and 1 year; and Forgotten Joint Score (FJS-12) at 1 year. Results All groups had similar KOOS and PROMIS-10 scores. MC knees had lower visual analog scale scores than PS knees at all time points ( P < .05) and a higher ROM than PS at 2 weeks (98.6 vs 93.7, P = .002). MC knees had a significantly higher FJS-12 than CR knees (71.6 vs 58.7, P = .02). More MC knees were “very satisfied” than CR (92.6% vs 81.5%, P = .04). Fewer MC knees were “not at all satisfied” than CR (1.2% vs 9.2%, P = .04). There were similar satisfaction ratings with MC and PS. Conclusions An MC bearing provided similar or improved early pain, ROM, KOOS, PROMIS-10, FJS-12, and patient satisfaction as compared with standard bearings in TKA.

Medially congruent total knee arthroplasty in valgus knee deformities yields satisfactory outcomes: a multicenter, international study

“…Interestingly, classic, medial pivot TKA designs showed favorable outcomes, reaching a 98.8% survivorship at 17 years [24]. The current authors recently reported no statistically significant clinical differences between posterior‐stabilized and medially congruent (MC) modern TKA designs; however, interestingly, MC knees showed better range of motion [10, 18]. Following these promising results, in 2016 the current authors started to use the MC design in Type‐II Ranawat deformities with the goal of reproducing a kinematically more medially dominated loading condition by correcting the preoperative malalignment and by obtaining an accurate, intraoperative ligament balance.…”

Native knee kinematics is not reproduced after sensor guided cruciates substituting total knee arthroplasty

“…The recent use of polyethylene designs alternative to the classic PS designs, especially medially constrained, has recently increased with the hope of reproducing normal knee kinematics and to mimic the physiologic medial pivoting pattern with posterolateral femoral roll-back in flexion [ 14 ], This “kinematic advantage” was hoped to translate into improved knee proprioception by the patient. Despite successful clinical outcomes, greater patient satisfaction, and higher forgotten joint scores (FJSs) when compared to traditional PS designs, the kinematic patterns of these designs failed to be similar to those of normal knees [ 16 , 18 , 23 , 37 , 41 ].…”

PCL retention demonstrates better functional scores and gait patterns in total knee arthroplasty using a medial congruent insert—a prospective study

“…Normal knee kinematics demonstrate rotating and pivoting action with minimal translation in the medial compartment and greater translation in the lateral compartment [17] resulting in a more constrained medial and less constrained lateral compartment. This allows for a combination of rolling and translational movement [8]. In deep lexion the medial femoral condyle maintains articulation with the posterior part of the medial tibial plateau, demonstrating an element of medial tibial rotation [14].…”

“…The MC insert with a medial “ball and socket” design provides medial conformity, anterior constraint and stability while allowing rotational freedom in the lateral compartment. These features attempt to approximate normal knee biomechanics [8, 18]. The improved articular geometry reduces polyethylene wear by minimizing contact force concentration and condylar lift‐off [19, 25].…”