Femoral and tibial insert downsizing increases the laxity envelope in TKA

Mueller, John Kyle P.; Wentorf, Fred A.; Moore, Richard E.

doi:10.1007/s00167-014-3339-0

Cited by 23 publications

(22 citation statements)

References 37 publications

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“…The loads applied in this study were similar to other in vitro TKA studies, yielding similar laxities [2, 24]. Saeki et al [31] found that under 35 N AP force, 10 Nm VV, and 1.5 Nm IE torques, MCL release increased laxity in cruciate-retaining TKA knees throughout flexion.…”

Section: Discussionsupporting

confidence: 81%

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty

Athwal

Daou

Inderhaug

et al. 2016

Knee Surg Sports Traumatol Arthrosc

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PurposeThe aim of this study was to quantify the medial soft tissue contributions to stability following constrained condylar (CC) total knee arthroplasty (TKA) and determine whether a medial reconstruction could restore stability to a soft tissue-deficient, CC-TKA knee.MethodsEight cadaveric knees were mounted in a robotic system and tested at 0°, 30°, 60°, and 90° of flexion with ±50 N anterior–posterior force, ±8 Nm varus–valgus, and ±5 Nm internal–external torque. The deep and superficial medial collateral ligaments (dMCL, sMCL) and posteromedial capsule (PMC) were transected and their relative contributions to stabilising the applied loads were quantified. After complete medial soft tissue transection, a reconstruction using a semitendinosus tendon graft was performed, and the effect on kinematic behaviour under equivocal conditions was measured.ResultsIn the CC-TKA knee, the sMCL was the major medial restraint in anterior drawer, internal–external, and valgus rotation. No significant differences were found between the rotational laxities of the reconstructed knee to the pre-deficient state for the arc of motion examined. The relative contribution of the reconstruction was higher in valgus rotation at 60° than the sMCL; otherwise, the contribution of the reconstruction was similar to that of the sMCL.ConclusionThere is contention whether a CC-TKA can function with medial deficiency or more constraint is required. This work has shown that a CC-TKA may not provide enough stability with an absent sMCL. However, in such cases, combining the CC-TKA with a medial soft tissue reconstruction may be considered as an alternative to a hinged implant.

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Section: Discussionsupporting

confidence: 81%

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty

Athwal

Daou

Inderhaug

et al. 2016

Knee Surg Sports Traumatol Arthrosc

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“…Fifth, the limits of passive motion would vary if a different tare load value was selected. Previous studies of in vitro knee laxity have applied compressive loads ranging from 20 N to 925 N . Increasing the compressive load decreases laxities in all degrees of freedom and decreases the contribution of the soft tissue restraints to stability .…”

Section: Discussionmentioning

confidence: 99%

“…After preconditioning, the limits of passive motion for I‐E, V‐V, A‐P, and C‐D were determined over a range of flexion angles from 0° to 120° in 15° increments using the prescribed loads listed above. A 45 N compressive tare load was applied throughout testing to simulate the passive compression across the joint that is generated by the muscles crossing the knee . First, the knee was moved to a randomly selected flexion angle.…”

Section: Methodsmentioning

confidence: 99%

“…A 45 N compressive tare load was applied throughout testing to simulate the passive compression across the joint that is generated by the muscles crossing the knee. 22 First, the knee was moved to a randomly selected flexion angle. Second, for a randomly selected degree of freedom, the prescribed positive load was applied followed by the prescribed negative load; both resulting positions were recorded.…”

Section: Measurement Of the Limits Of Passive Motionmentioning

confidence: 99%

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The limits of passive motion are variable between and unrelated within normal tibiofemoral joints

Roth

Hull

Howell

2015

Journal Orthopaedic Research

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Patient-to-patient differences should be accounted for in both clinical evaluations and computational models of knee laxity. Accordingly, the objectives were to determine how variable the laxities are between knees by determining the range of the internal-external (I-E), varus-valgus (V-V), anterior-posterior (A-P), and compression-distraction (C-D) limits of passive motion, and how related the laxities are within a knee by determining whether these limits are correlated with one another. The limits in I-E (AE 3 Nm), V-V (AE 5 Nm), A-P (AE 45 N), and C-D (AE 100 N) were measured in 10 normal human cadaveric knees at 0˚to 120˚flexion in 15i ncrements using a six degree-of-freedom load application system. The ranges from 15˚to 120˚flexion of the I-E limits were greater than 3.6˚, of the A-P limits were greater than 1.8 mm, and of the varus limits were greater than 1.4˚. The ranges from 30˚to 120f exion of the distraction limits were greater than 2.0 mm. Twenty-four of the 28 pair-wise comparisons between the limits had a correlation coefficient less than 0.65. These results demonstrate that a patient-specific approach, including all degrees of freedom of interest, is necessary during clinical evaluations of laxity and when creating and validating computational models of the tibiofemoral joint. Keywords: limits of passive motion; patient-specific modeling; laxity; knee It is important to characterize the patient-to-patient differences in the laxities of the tibiofemoral joint of the normal human knee in various degrees of freedom. The laxities of the normal human knee are often used both as a benchmark by orthopedic surgeons when evaluating laxities before, during, and after surgical interventions (e.g., total knee arthroplasty) 1 and as a gold standard by researchers when validating computational models of the tibiofemoral joint.2,3 Passive kinematics of the tibiofemoral joint are guided by the interaction between the soft tissue restraints and the articular geometry. However, the restraints from both the soft tissues and articular geometry are different between individuals. 4 Because the laxities are a measure of the function of the soft tissue restraints and the articular geometry, abnormal laxities indicate abnormal function. Therefore, it is critical to characterize the patientto-patient differences in the laxities so they may be accounted for during clinical evaluations of laxity and when creating computational models of the knee to study the behavior of the soft tissue restraints.There are two types of patient-to-patient differences that are of interest with regards to the laxities of the tibiofemoral joint. The first is the variability of the laxities between knees. If there is a wide variability as characterized by a wide range of the laxities, then a patient-specific approach would be necessary both during clinical evaluations of laxity and when creating computational models of the knee to study the behavior of the soft tissue restraints. The second is the relationship between the laxity in one ...

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“…Another recently highlighted reason as cause of midflexion instability is component downsizing: a 2-mm downsizing on the femoral component and a 1-mm downsizing on the tibial component had an equivalent increase in laxity in mid-flexion [12]. Mid-flexion instability surgical treatments, at the time of TKA revision, usually include increasing the femoral condylar offset, proximalization of the joint line, and decreasing of the posterior tibial slope.…”

Section: Flexion/extension Gap Mismatchmentioning

confidence: 98%

Level of constraint in revision knee arthroplasty

Indelli

Giori

Maloney

2015

Curr Rev Musculoskelet Med

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Revision total knee arthroplasty (TKA) in the setting of major bone deficiency and/or soft tissue laxity might require increasing levels of constraint to restore knee stability. However, increasing the level of constraint not always correlates with mid-to-long-term satisfactory results. Recently, modular components as tantalum cones and titanium sleeves have been introduced to the market with the goal of obtaining better fixation where bone deficiency is an issue; theoretically, satisfactory meta-diaphyseal fixation can reduce the mechanical stress at the level of the joint line, reducing the need for high levels of constraint. This article reviews the recent literature on the surgical management of the unstable TKA with the goal to propose a modern surgical algorithm for adult reconstruction surgeons.

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Femoral and tibial insert downsizing increases the laxity envelope in TKA

Cited by 23 publications

References 37 publications

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty

An in vitro analysis of medial structures and a medial soft tissue reconstruction in a constrained condylar total knee arthroplasty

The limits of passive motion are variable between and unrelated within normal tibiofemoral joints

Level of constraint in revision knee arthroplasty

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