Midflexion Instability in Primary Total Knee Arthroplasty

Nagle, Matthew; Glynn, Aaron

doi:10.1055/s-0039-1678537

Cited by 14 publications

(11 citation statements)

References 63 publications

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“…Martin and Whiteside 1 defined mid-flexion instability following total knee arthroplasty (TKA) as instability between 0° and 90° in the absence of instability in full extension or in 90° of flexion. Mid-flexion stability is believed to be an important factor influencing successful clinical outcomes following TKA 2-10 .…”

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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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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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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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“…Their study was unable to demonstrate a significant difference between the two implants, but Hino et al found a greater degree of varus–valgus laxity between 10° and 90° of flexion with posterior stabilised TKRs compared to CR TKRs [ 52 , 53 ]. Long-term outcome studies have not diagnosed mid-flexion instability in both posterior stabilised TKRs and CR TKRs with multi-radius components, though this should be interpreted with caution, as it may well result from under-recognition of mid-flexion instability ( 39 , 42 , 51 – 54 ). Overall, there is a need for further clinical studies into femoral component design or implants and mid-flexion instability to be able to make any reliable conclusions.…”

Section: Methodsmentioning

confidence: 99%

Management of instability after primary total knee arthroplasty: an evidence-based review

et al. 2021

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Background Instability is one of the most common reasons for revision after a total knee replacement. It accounts for 17.4% of all single-stage revision procedures performed in the UK National Joint Registry. Through a careful patient evaluation, physical assessment and review of investigations one can identify the likely type of instability. Aims To critically examine the different types of instability, their presentation and evidence-based management options. Method A comprehensive literature search was conducted to identify articles relevant to the aetiology and management of instability in total knee replacements. Results Instability should be categorised as isolated or global and then, as flexion, mid-flexion, extension or recurvatum types. By identifying the aetiology of instability one can correctly restore balance and stability. Conclusion With careful judgement and meticulous surgical planning, instability can be addressed and revision surgery can provide patients with successful outcomes.

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“…However, postoperative knee instability is not well defined clinically, and the boundaries between stable and unstable TKA knees is still poorly understood. This lack of understanding is likely due to the multitude of factors that are associated knee instability, including inadequate soft tissue balancing (1,2), loss of ligamentous integrity (3), and improper component sizing (3,4).…”

Section: Introductionmentioning

confidence: 99%

Comparable in vivo joint kinematics between self-reported stable and unstable knees after TKA can be explained by muscular adaptation strategies: a retrospective observational study

Rao

Horn

Meister

et al. 2022

Preprint

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Background:Postoperative knee instability is one of the major reasons accounting for unsatisfactory outcomes, as well as a major failure mechanism leading to total knee arthroplasty (TKA) revision. Nevertheless, subjective knee instability is not well defined clinically, plausibly because the relationships between instability and implant kinematics during functional activities of daily living remain unclear. Although muscles play a critical role in supporting the dynamic stability of the knee joint, the influence of joint instability on muscle synergy patterns is poorly understood. Therefore, this study aimed to understand the impact of self-reported joint instability on tibiofemoral kinematics and muscle synergy patterns after TKA during functional gait activities of daily living.Methods:Tibiofemoral kinematics and muscle synergy patterns were examined during level walking, downhill walking, and stair descent in eight self-reported unstable knees after TKA (3M:5F, 68.9±8.3 years, BMI 26.1±3.2 kg/m2, 31.9±20.4 months postoperatively), and compared against ten stable TKA knees (7M:3F, 62.6±6.8 years, 33.9±8.5 months postoperatively, BMI 29.4±4.8 kg/m2). For each knee joint, clinical assessments of postoperative outcome were performed, while joint kinematics were evaluated using moving video-fluoroscopy, and muscle synergy patterns were recorded using electromyography.Results:Our results reveal that average condylar A-P translations, rotations, as well as their ranges of motion were comparable between stable and unstable groups. However, the unstable group exhibited more heterogeneous muscle synergy patterns and prolonged activation of knee flexors compared to the stable group. In addition, subjects who reported instability events during measurement showed distinct, subject-specific tibiofemoral kinematic patterns in the early/mid-swing phase of gait.Conclusions:Our findings suggest that accurate movement analysis is sensitive for detecting acute instability events, but might be less robust in identifying general joint instability. Conversely, muscle synergy patterns seem to be able to identify muscular adaptation associated with underlying chronic knee instability.Funding:This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

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Midflexion Instability in Primary Total Knee Arthroplasty

Cited by 14 publications

References 63 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

Management of instability after primary total knee arthroplasty: an evidence-based review

Comparable in vivo joint kinematics between self-reported stable and unstable knees after TKA can be explained by muscular adaptation strategies: a retrospective observational study

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