Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model

Objective: The purpose of this radiological study was to assess the posterior laxity of a single model of a total knee arthroplasty design (TKA) having a medially constrained (MC) or a Posterior-Stabilized (PS) polyethylene insert using a well-documented stress x-ray. To the authors knowledge, this...

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Main Authors: Leonardo Stramazzo, Nicolo’ Bassi, Stefano Ghirardelli, Tommaso Amoroso, Leonardo Osti, Pier Francesco Indelli
Format: Article
Language:English
Published: SAGE Publishing 2022-12-01
Series:Journal of Orthopaedics, Trauma and Rehabilitation
Online Access:https://doi.org/10.1177/2210491720978988
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author Leonardo Stramazzo
Nicolo’ Bassi
Stefano Ghirardelli
Tommaso Amoroso
Leonardo Osti
Pier Francesco Indelli
author_facet Leonardo Stramazzo
Nicolo’ Bassi
Stefano Ghirardelli
Tommaso Amoroso
Leonardo Osti
Pier Francesco Indelli
author_sort Leonardo Stramazzo
collection DOAJ
description Objective: The purpose of this radiological study was to assess the posterior laxity of a single model of a total knee arthroplasty design (TKA) having a medially constrained (MC) or a Posterior-Stabilized (PS) polyethylene insert using a well-documented stress x-ray. To the authors knowledge, this is the first report evaluating MC TKA outcomes according to the “kneeling view.” Materials and Methods: Sixty patients with non-traumatic primary knee osteoarthritis undergoing TKA were first matched by age, sex, BMI and diagnosis and then divided in two groups: group A (37 knees) received a MC TKA and group B (23 knees) a PS implant made by the same manufacturer. In all cases the posterior cruciate ligament (PCL) was resected. All patients underwent the same postoperative “kneeling view” and were also clinically evaluated according to the Knee Society Score (KSS) and Oxford Knee Score (OKS). Radiographic measurements were taken by tracing a line along the posterior cortex of the tibia and then measuring the perpendicular distance to a point marked at the posterior corner of Blumensaat’s line. Results: At 12 months minimum FU, no statistically significant differences were found between the two groups in all the clinical scores. There was a statistically significant difference on kneeling view values between the two groups (P = 0.0002): the mean value in the MC group was −1.97 ± 3.8 mm while was −5.6 ± 3.1 mm in the PS group. In both groups, the average position of the posterior cortex of the tibia was anterior to the posterior corner of Blumensaat’s line, showing absence of instability in flexion. Conclusion: This study highlighted that the PCL removal, accompanied by a precise surgical technique, did not increase the instability in flexion in two groups of patients having the same TKA design but polyethylene inserts characterized by different levels of constraint.
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spelling doaj-art-e9ec22e9317f4bae81e7fc493d2cc38b2025-08-20T01:57:35ZengSAGE PublishingJournal of Orthopaedics, Trauma and Rehabilitation2210-49252022-12-012910.1177/2210491720978988Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single modelLeonardo Stramazzo0Nicolo’ Bassi1Stefano Ghirardelli2Tommaso Amoroso3Leonardo Osti4Pier Francesco Indelli5 Universita degli Studi di Palermo, Palermo, Sicilia, Italy Universita degli Studi di Palermo, Palermo, Sicilia, Italy Stanford University, School of Medicine, Stanford, CA, USA Universita degli Studi di Palermo, Palermo, Sicilia, Italy Universita degli Studi di Palermo, Palermo, Sicilia, Italy Stanford University, School of Medicine, Stanford, CA, USAObjective: The purpose of this radiological study was to assess the posterior laxity of a single model of a total knee arthroplasty design (TKA) having a medially constrained (MC) or a Posterior-Stabilized (PS) polyethylene insert using a well-documented stress x-ray. To the authors knowledge, this is the first report evaluating MC TKA outcomes according to the “kneeling view.” Materials and Methods: Sixty patients with non-traumatic primary knee osteoarthritis undergoing TKA were first matched by age, sex, BMI and diagnosis and then divided in two groups: group A (37 knees) received a MC TKA and group B (23 knees) a PS implant made by the same manufacturer. In all cases the posterior cruciate ligament (PCL) was resected. All patients underwent the same postoperative “kneeling view” and were also clinically evaluated according to the Knee Society Score (KSS) and Oxford Knee Score (OKS). Radiographic measurements were taken by tracing a line along the posterior cortex of the tibia and then measuring the perpendicular distance to a point marked at the posterior corner of Blumensaat’s line. Results: At 12 months minimum FU, no statistically significant differences were found between the two groups in all the clinical scores. There was a statistically significant difference on kneeling view values between the two groups (P = 0.0002): the mean value in the MC group was −1.97 ± 3.8 mm while was −5.6 ± 3.1 mm in the PS group. In both groups, the average position of the posterior cortex of the tibia was anterior to the posterior corner of Blumensaat’s line, showing absence of instability in flexion. Conclusion: This study highlighted that the PCL removal, accompanied by a precise surgical technique, did not increase the instability in flexion in two groups of patients having the same TKA design but polyethylene inserts characterized by different levels of constraint.https://doi.org/10.1177/2210491720978988
spellingShingle Leonardo Stramazzo
Nicolo’ Bassi
Stefano Ghirardelli
Tommaso Amoroso
Leonardo Osti
Pier Francesco Indelli
Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
Journal of Orthopaedics, Trauma and Rehabilitation
title Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
title_full Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
title_fullStr Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
title_full_unstemmed Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
title_short Posterior stability in posterior-stabilized vs medially congruent total knee replacement: A radiological comparison of two polyethylene designs in a single model
title_sort posterior stability in posterior stabilized vs medially congruent total knee replacement a radiological comparison of two polyethylene designs in a single model
url https://doi.org/10.1177/2210491720978988
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