Medial rather than lateral knee instability correlates with inferior patient satisfaction and knee function after total knee arthroplasty

doi:10.1016/j.knee.2017.09.004

The Knee

Volume 24, Issue 6, December 2017, Pages 1478-1484

https://doi.org/10.1016/j.knee.2017.09.004 Get rights and content

Abstract

Background

It is commonly thought that balanced medial and lateral tibiofemoral joint gaps are essential, but the effect of joint laxity on clinical outcome after total knee arthroplasty (TKA) is unclear. It was hypothesised that medial joint laxity correlates with inferior patient satisfaction and knee function, although lateral joint laxity is allowed to a certain degree in TKA.

Methods

This study included 50 knees that underwent primary TKA. Knee laxity was measured with postoperative stress radiographs in flexion and extension, and patient satisfaction and knee function were evaluated by the 2011 Knee Society Knee Scoring System.

Results

In a comparison of medially tight and medially loose knees in flexion, the scores for satisfaction, symptoms, standard activity, and advanced activity were significantly better in medially tight than in medially loose knees (satisfaction: 29.8, 22.2; symptoms: 20.3, 15.9; standard activities: 24.2, 19.1; and advanced activities: 15.3, 8.7, in the tight and loose knees, respectively). Neither lateral joint laxity during knee flexion nor medial joint laxity during knee extension was associated with a poor postoperative clinical outcome, whereas lateral joint laxity and the standard activity score in extension had a moderate positive correlation.

Conclusions

Knees with medial joint laxity during flexion resulted in an inferior postoperative outcome, and lateral joint laxity did not influence patient satisfaction or function. Care should be taken to maintain medial joint stability during the TKA procedure.

Introduction

Many pre- and postoperative factors can affect patient satisfaction and knee function after total knee arthroplasty (TKA) [1], [2], [3], [4]. Ligament balancing is one of the key surgical elements used to improve postoperative knee function [5], [6]. It is commonly thought that balanced medial and lateral gaps are essential, and that imbalanced gaps lead to malfunction and failure [7], [8].

In contrast, a magnetic resonance imaging (MRI) analysis showed that in normal knees at 90° of flexion the lateral joint gap was larger than the medial joint gap [9]. Another study also reported that the lateral extension gap was slightly more lax compared with the medial extension gap in a radiographic analysis [10]. In addition, recent studies showed that intraoperative lateral joint laxity at 90° knee flexion was an important factor affecting postoperative knee flexion angle after TKA [11], because lateral joint laxity from mid-to-deep knee flexion played an important role in determining internal tibial rotation against the femoral component [12]. Achieving good range of motion certainly has a great clinical impact on patient satisfaction after TKA [13], [14], but the question arises whether successful TKA is possible using unequal medial and lateral joint gaps. Few studies have evaluated in detail the effect on patient symptoms of medial–lateral knee stability during knee flexion, and achieving the relevant amount of soft tissue balancing in TKA is clinically beneficial for predicting postoperative patient satisfaction.

In this study, it was hypothesised that medial joint laxity would be associated with lower patient satisfaction, more severe symptoms, and reduced functional activities as measured with the 2011 Knee Society Knee Scoring System (2011 KS), though lateral joint laxity would be permissible to a certain degree in TKA.

Section snippets

Participants

Three-hundred and forty-three primary TKAs were performed with the Bi-Surface knee system (Kyocera Medical, Osaka, Japan) at our institute between June 2003 and October 2011 [15]. This retrospective case series analysed 50 knees in 41 patients who made regular clinic visits from November 2012 to December 2013 and who agreed to participate in this study.

The exclusion criteria included knees with either valgus deformity or severe bony defects requiring bone grafting or augmentation. Of the 57

Results

Postoperative 2011 KS scores showed that the mean satisfaction score (out of 40) was 25.5 (SD 10.5; range six to 40), the symptoms score (25) was 18.0 (SD 6.9; range 0–25), the expectations score (15) was 9.0 (SD 2.8; range three to 15), the walking and standing score (30) was 20.8 (SD 7.9; range two to 30), the standard activities score (30) was 21.5 (SD 7.1; range 0–30), and the advanced activities score (25) was 11.7 (SD 6.6; range 0–25).

The mean postoperative knee extension and flexion

Discussion

The present findings demonstrate that medial joint laxity is related to inferior satisfaction and knee function as determined by 2011 KS scores after TKA. Medial stability is very important in TKA because the medial collateral ligament (MCL) is a secondary restraint to anterior instability [23]. Since almost all post-TKA knees lack an anterior cruciate ligament (ACL), medial joint laxity coupled with the absence of the ACL increases dynamic instability, reducing postoperative knee function. The

Conclusions

Knees with medial joint laxity in flexion resulted in an inferior postoperative outcome, and lateral joint laxity did not affect patient satisfaction or knee function. It is proposed that to improve patient satisfaction and knee function, care should be taken to maintain medial stability during TKA.

Conflict of interest

The authors declare that they have no conflicts of interest.

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The anterior positions of the medial and lateral femoral condyles at mid-flexion and maximum flexion had negative impacts on PROMs. Soft tissue conditions should be carefully managed to achieve medial knee joint stability, which can improve PROMs.
Comparison of knee kinematics and ligament forces in single and multi-radius cruciate-retaining total knee arthroplasty: A computer simulation study
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These suggest that abrupt changes in the medial collateral ligament force influence anterior sliding of the femur, and that the single-radius design is a reasonable choice for prevention of mid-flexion instability.
Laxity, Balance, and Alignment of a Simulated Kinematic Alignment Total Knee Arthroplasty
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We used data from 382 robot-assisted TKA performed with a digital joint tensioner to simulate TKA with a pure resurfacing KA technique for both femur and tibia. All knees had the posterior cruciate ligament retained. Knees were subdivided into 4 groups based on preoperative coronal alignment: valgus, neutral, varus, and high varus. Medial and lateral laxity in extension and flexion, balance in extension and flexion, and coronal plane alignment were compared between groups using analysis of variance testing.
In simulated pure resurfacing KA TKA across a range of preoperative coronal plane deformities, only 11%-31% of knees would have mediolateral extension ligament balance within ±1 mm, and 20%-41% would have a medial flexion gap that is looser than the lateral flexion gap. Over 45% of knees would have coronal hip-knee-ankle angle >3 degrees from mechanical neutral.
In simulations of pure resurfacing KA TKA, there was wide variability in the resulting laxity and alignment outcomes. Most knees had alignment and balance outcomes outside of normally accepted ranges. Techniques that deviate from pure resurfacing in order to achieve balance appear favorable.
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Although bicruciate stabilized total knee arthroplasty (BCS-TKA) is expected to provide kinematics similar to those of the normal knee, there are limited data available for comparison of the kinematics of the knee after BCS-TKA with those of the normal knee. The purpose of this study was to confirm whether the knee after BCS-TKA are the same as those of the native knee.
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Tibiofemoral lift-off and resulting laxity following total knee arthroplasty: Frequency in a series of 906 continuous cases and functional consequences at 4 years’ follow-up in a case-control study
2022, Revue de Chirurgie Orthopedique et Traumatologique
L’instabilité fémoro-tibiale est une cause de reprise précoce des arthroplasties de genou. Elle peut être la conséquence d’une laxité fémoro-tibiale notamment dans le plan frontal avec une décoaptation fémoro-tibiale. Les radiographies standards postopératoires avec une décoaptation (lift-off) fémoro-tibiale peuvent-elles faire craindre une laxité ou une possible instabilité ? À notre connaissance, cette relation n’a jamais été testée. Aussi nous avons mené une étude rétrospective pour évaluer : (1) la fréquence du lift-off sur les radiographies postopératoires, (2) la relation entre lift-off et laxité à court terme, (3) les conséquences fonctionnelles.
Le lift-off postopératoire est un événement rare et prédictif d’une laxité.
Nous avons mené une étude rétrospective, monocentrique sur les radiographies postopératoires entre 2014 et 2016 des patients opérés d’une arthroplastie totale de genou de première intention. Nous avons évalué 906 patients et le lift-off a été défini par un angle fémoro-tibial supérieur ou égal à 3° en postopératoire immédiat (J0) en décharge et sans contrainte. Une analyse fonctionnelle a été menée sur les 17 patients avec un lift-off qui avaient été opérés la première année (2014) afin d’avoir un recul suffisant. Ils ont été comparés à 34 patients appariés opérés la même année, en incluant au hasard au sein des patients sans lift-off avec un ratio 2 pour 1 soit 34 patients. Les données préopératoires et opératoires ont été recueillies à partir du dossier informatique de chaque patient. Les patients ont été évalués à 4 ans postopératoire et évalués par un score subjectif Oxford-48, un score objectif HSS, un score IKS et une évaluation de la satisfaction globale du patient et analyse radiologique avec cliché en stress. Les cas de lift-off observés en 2014 (n = 17) ont été appariés avec un groupe contrôle constitué rétrospectivement sur l’année 2014.
La fréquence de l’événement, « lift-off » était de 63/906 soit 7 % et de fréquence régulière sur 3 ans (2014 à 2016) : en 2014, 7,1 % (19/269), en 2015, 6,2 % (22/354) et en 2016, 7,8 % (22/283). L’analyse fonctionnelle n’a pas mis en évidence de différence significative entre les deux groupes (17 avec lift-off versus 34 sans lift-off) pour le genre, l’âge, l’indice de masse corporelle, la déformation selon l’angle HKA préopératoire. Pour l’étude fonctionnelle au recul de 4 ans (12–49 mois), les genoux avec lift-off postopératoire étaient plus laxes (p = 0,002), et notamment pour la laxité en stress en varus (p = 0,009). Il n’a pas été mis en évidence d’autre différence significative.
Le lift-off postopératoire immédiat des prothèses de genou est un événement, qui n’est pas rare, avec 7 % de fréquence dans notre étude. Même s’il témoigne d’une laxité, du compartiment concerné, il n’y a pas été mis en évidence de conséquence fonctionnelle au recul observé, mais une observation à plus long terme est nécessaire pour valider ce résultat.
III, étude cas témoin.

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¹: These authors contributed equally to this article.

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Medial rather than lateral knee instability correlates with inferior patient satisfaction and knee function after total knee arthroplasty

Abstract

Background

Methods

Results

Conclusions

Introduction

Section snippets

Participants

Results

Discussion

Conclusions

Conflict of interest

J Arthroplasty

J Arthroplasty

J Arthroplasty

J Orthop Sci

J Arthroplasty

J Arthroplasty

J Orthop Sci

J Arthroplasty

J Arthroplasty

J Orthop Sci

J Arthroplasty

What are the factors of residual pain after uncomplicated TKA?

Knee Surg Sports Traumatol Arthrosc

Patient satisfaction after total knee arthroplasty: who is satisfied and who is not?

Clin Orthop Relat Res