Outcomes are Better With a Medial-Stabilized vs a Posterior-Stabilized Total Knee Implanted With Kinematic Alignment

Scott, David F.; Gray, Celeste G

doi:10.1016/j.arth.2022.02.059

Cited by 25 publications

(32 citation statements)

References 65 publications

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“…Our results suggest that this was not true for the implants used in the present study; despite the MS design having greater conformity than the PS design, the range of motion was similar (mean flexion, 127.3°compared with 128.8°, respectively; p = 0.73). In the parent study 38 , with 200 randomized patients, mean flexion at 2 years was greater in the implant group with greater conformity: 132°in the MS group and 124°in the PS group (p < 0.0001), and the single instance of aseptic loosening occurred in the lower-conformity PS group. While there may be concern that greater articular conformity leads to increased interface shear stresses that could affect the longevity of fixation, perhaps a knee implant with sagittal constraint coupled with unconstrained rotation, as with this MS implant, mitigates interface shear stresses 69 .…”

Section: Discussionmentioning

confidence: 90%

“…The study was conducted between January 2016 and November 2018, and all participants provided informed consent. The participants were randomly selected from a prospective, randomized trial 38 (the "parent study") comparing a PS implant and an MS implant (Medacta GMK PS or Sphere; Medacta International), and additional inclusion/exclusion criteria (developed to identify optimally functioning, stable TKA implants with excellent range of motion) were utilized. All subjects in the parent study (n = 200) were screened to identify those who had undergone the procedure in the last 1 to 2 years.…”

Section: Patient Selectionmentioning

confidence: 99%

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Mid-Flexion, Anteroposterior Stability of Total Knee Replacement Implanted with Kinematic Alignment

Scott

Hellie

2022

Journal of Bone and Joint Surgery

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UpdateThis article was updated on January 4, 2023, because of a previous error, which was discovered after the preliminary version of the article was posted online. On page 16, in Figure 5, the x-axis that had read “P<0.0086” now reads “KSS Pain (p=0.02),” and the value for the MS group that had read “48.9” now reads “48.8.”This article was updated on January 6, 2022, because of a previous error. On page 13, in the section entitled “Results,” the sentence that had read “However, when only the subset of female subjects was considered, the MS group demonstrated significantly less anteroposterior laxity in 90° of flexion than the MS group (2.3 versus 5.4 mm; p = 0.008).” now reads “However, when only the subset of female subjects was considered, the MS group demonstrated significantly less anteroposterior laxity in 90° of flexion than the PS group (2.3 versus 5.4 mm; p = 0.008).”Background:Stability in mid-flexion is important for satisfactory clinical outcomes following total knee arthroplasty (TKA). The purpose of the present study was to compare the anteroposterior stability of knees that had been treated with a posterior-stabilized (PS) device or a medial-stabilized (MS) device. We hypothesized that mid-flexion laxity would be greater in the PS group and that clinical outcome scores would be better for the group with lower laxity.Methods:Sixty-three patients who had been randomly selected from a larger randomized, prospective, blinded clinical trial underwent primary TKA with either a PS implant (n = 30) or an MS implant (n = 33). Range of motion, the Knee Society Score (KSS), and the Forgotten Joint Score (FJS) were collected, and anteroposterior laxity with the knee in 45° and 90° of flexion was evaluated with stress radiographs.Results:In 45° of flexion, the MS group demonstrated significantly less total anteroposterior displacement than the PS group (mean, 3.6 versus 16.5 mm; p ≤ 0.0001). In 90° of flexion, the total anteroposterior displacement was not significantly different for the 2 groups when both male and female patients were included (mean, 3.9 versus 5.9; p = 0.07). However, when only the subset of female subjects was considered, the MS group demonstrated significantly less anteroposterior laxity in 90° of flexion than the PS group (2.3 versus 5.4 mm; p = 0.008). The groups did not differ significantly in terms of preoperative age, body mass index, sex distribution, FJS, KSS, or range of motion, and they also did not differ in terms of postoperative FJS or range of motion. However, all 33 patients in the MS group returned to sports as indicated in question 12 of the FJS, compared with 19 subjects in the PS group (p = 0.0001). The postoperative KSS Pain, Pain/Motion, and Function scores were all significantly higher in the MS group than the PS; specifically, the mean KSS Pain score was 48.8 in the MS group, compared with 44.8 in the PS group (p = 0.02); the mean KSS Pain/Motion score was 98.4 in the MS group, compared with 89.5 in the PS group (p < 0.0001); and the mean KSS Function score was 95.5 in ...

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Section: Discussionmentioning

confidence: 90%

Section: Patient Selectionmentioning

confidence: 99%

Mid-Flexion, Anteroposterior Stability of Total Knee Replacement Implanted with Kinematic Alignment

Scott

Hellie

2022

Journal of Bone and Joint Surgery

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“…Regarding the MC bearing, a meta-analysis ( 47 ) reported similar WOMAC and KSS, but improved forgotten joint scores with the MC bearing, and clinical studies have shown improved pain, satisfaction, and ROM with the MC compared to posterior stabilized components ( 48 , 49 ). Of particular importance to the Personalized Alignment technique, a recent study reported better 2-year ROM (8°), KSS pain scores (8 points), and forgotten joint scores (10 points) when performing KA with a medial-stabilized compared to a posterior stabilized component ( 50 ). Preliminary data from a single surgeon study also suggests better Knee Injury and Osteoarthritis Outcome Scores (KOOS) for quality of life and forgotten joint scores at 1-year follow-up with a medial-stabilized component compared to a cruciate retaining design ( 51 ) with rKA, while a greater incidence of tibial implant loosening and lower survival have been reported when a posterior stabilized component was used in rKA ( 52 ).…”

Section: Expected Outcomesmentioning

confidence: 99%

Personalized alignment™ for total knee arthroplasty using the ROSA® Knee and Persona® knee systems: Surgical technique

2023

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Total knee arthroplasty (TKA) procedures are expected to increase up to 565% in the United States over the next 3 decades. TKAs were traditionally performed with neutral mechanical alignments that provided equal medial and lateral gaps in extension and flexion to reduce implant wear but were less successful at restoring native knee function and associated with high patient dissatisfaction. Kinematic alignment (KA) restores native anatomy and minimizes soft tissue release; however, KAs that recreate severe deformities and/or biomechanically inferior alignments result in significant increases in implant stress and risk of aseptic loosening. Restricted kinematic alignment (rKA) recreates pre-arthritic anatomy within a range of acceptable alignment boundaries, and improved patient clinical scores and faster recoveries have been reported with rKA techniques. Personalized Alignment™ is an evolution of rKA that relies heavily upon robotic assistance to reliably recreate patient anatomy, native soft tissue laxity, and accurate component placement to improve patients' clinical outcomes. The purpose of this surgical technique report is to describe the Personalized Alignment TKA method using the ROSA® Knee System and Persona® The Personalized Knee® implants. Herein we provide specific procedures for pre-operative planning, anatomical landmarking and evaluation, intra-operative planning and adjustment of resections and cuts, cut validation and soft tissue evaluation with robotic-assisted personalized TKA.

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“…Since the late 1990s, there has been a growing interest in closely mimicking the physiological medial-pivoting movement and the rollback of the lateral femoral condyle of the native knee, which, when combined, determine the internal axial rotation of the tibia relative to the femur during flexion [ 1 , 2 , 3 , 4 ]. Randomized trials and kinematic studies report clinical and biomechanical improvements using the medial-pivot design relative to low-congruent posterior cruciate ligament (PCL) retaining (CR), posterior-substituting (PS), and ultracongruent (UC) designs [ 5 , 6 , 7 , 8 ]. However, the consequences of adding different levels of congruency to the lateral insert are less clear, especially when there is excessive tension in the PCL that can overconstrain the flexion space which is detected by anterior lift-off of the trial insert from the tibial baseplate at 90° flexion [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

A TKA Insert with A Lateral Flat Articular Surface Maximizes External and Internal Tibial Orientations without Anterior Lift-Off Relative to Low- and Ultracongruent Surfaces

Nedopil

Howell

Hull

2022

JPM

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Background: In total knee arthroplasty (TKA), inserts can have different levels of medial and lateral congruency determined by the acuteness of the upslopes of the anterior and posterior articular surfaces. The present study evaluated an insert with different levels of lateral congruency and a medial ball-in-socket congruency to test the hypothesis that a lateral flat (F) insert maximizes external tibial orientation at extension and internal orientation at 90° flexion and lowers the incidence of anterior lift-off relative to low-congruent (LC) and ultracongruent (UC) lateral inserts. Methods: Two surgeons treated 23 patients with unrestricted caliper-verified kinematic alignment (KA) and posterior cruciate ligament (PCL) retention. They randomly trialed inserts with a medial radial dial that functioned as a built-in goniometer by measuring the tibial orientation relative to a sagittal line on the femoral trial component. Anterior lift-off of the insert from the baseplate indicated PCL tightness. Results: The F insert’s mean of 9° of external tibial orientation was higher than that of the LC (5°, p < 0.0001) and UC inserts (2°, p < 0.0001). The −13° of internal tibial orientation at 90° flexion was higher than that of the LC (−9°, p < 0.0001) and UC inserts (−7°, p < 0.0001). The 0% incidence of anterior lift-off was less than that of the LC (26%) and UC inserts (57%) (p < 0.0001). Conclusions: Surgeons and implant manufacturers should know that adding congruency to the lateral articular surface limits external tibial orientation in extension and internal tibial orientation at 90° flexion and overtightens the PCL. These rotational limitations and flexion space tightness can adversely affect patellofemoral tracking and knee flexion.

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Outcomes are Better With a Medial-Stabilized vs a Posterior-Stabilized Total Knee Implanted With Kinematic Alignment

Cited by 25 publications

References 65 publications

Mid-Flexion, Anteroposterior Stability of Total Knee Replacement Implanted with Kinematic Alignment

Mid-Flexion, Anteroposterior Stability of Total Knee Replacement Implanted with Kinematic Alignment

Personalized alignment™ for total knee arthroplasty using the ROSA® Knee and Persona® knee systems: Surgical technique

A TKA Insert with A Lateral Flat Articular Surface Maximizes External and Internal Tibial Orientations without Anterior Lift-Off Relative to Low- and Ultracongruent Surfaces

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