Leaving Residual Varus Alignment After Total Knee Arthroplasty Does Not Improve Patient Outcomes

Meneghini, R. Michael; Grant, Tanner W.; Ishmael, Marshall K.; Ziemba-Davis, Mary

doi:10.1016/j.arth.2017.02.064

Cited by 31 publications

(38 citation statements)

References 49 publications

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“…[17][18][19] The main finding of this study was that patients with TKA due to varus osteoarthritis who were corrected into their "natural" alignment with a remaining slight varus have superior functional results compared with patients with a neutral alignment postoperatively. This result is in contrast to the findings reported by Meneghini et al 15 who performed a retrospective cohort analysis of 176 cases of TKA with preoperatively varus deformity. A total of 116 patients were corrected to neutral alignment and 45 patients had a residual varus, whereas 15 patients were overcorrected to valgus alignment.…”

Section: Discussioncontrasting

confidence: 99%

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Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

Schiffner

Wild

Regenbrecht³

et al. 2018

J Knee Surg

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Total knee arthroplasty (TKA) is a very successful procedure. The alignment in TKA has been identified as being of importance to prevent early implant failure and patient dissatisfaction. Our hypothesis was that patients with a preoperative varus deformation remaining in a slight varus alignment as their natural alignment after TKA will have superior clinical results compared with patients who are restored in neutral alignment. A total of 115 patients were corrected from varus to neutral (varus-neutral) and in 33 patients a preoperative varus alignment was kept in varus (varus). Standardized preoperative and postoperative full-length hip-knee-ankle radiographs under full weight-bearing conditions were performed in all patients. The patients' knees were categorized preoperatively and postoperatively based on the angle between mechanical femoral axis and mechanical tibial axis. Knees with alignment between ± 3 degrees were categorized as neutrally aligned, whereas alignment within ≤ -3 degrees was categorized as varus. The Knee Injury Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score were determined retrospectively. The varus group scored significantly better in total KOOS ( < 0.05) compared with the varus-neutral group. Also, a trend was visible in the Oxford Knee Score but this was not significant ( > 0.05). This trend was even more evident in varus knees which were slightly undercorrected. The results support the assumption that leaving a residual varus alignment after TKA leads to better functional outcomes in TKA for patients with preoperative varus osteoarthritis.

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Section: Discussioncontrasting

confidence: 99%

“…Restoring a neutral alignment is the current gold standard. 15,16 However, this has been discussed controversially in the literature. 9 Several authors postulated that a persisting varus alignment after TKA yields a risk of failure of TKA and patients' dissatisfaction.…”

Section: Discussionmentioning

confidence: 99%

Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

Schiffner

Wild

Regenbrecht³

et al. 2018

J Knee Surg

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“…When forces were measured after cementing the implant and choosing the insert thickness they reported an average tibial force of 112 AE 46 lb which is five times greater than those of the native knee. 18 A tibial compartment force that results in 13 lbs of tensile force in the ligamentous complex places the force-elongation curve in a region of high stiffness which indicates imbalance and over-tensioning of the knee. 19 Therefore, the intraoperative use of an instrumented tibial insert provides the surgeon with real-time feedback to lower compartment forces by fine-tuning implant positions and releasing ligaments which minimizes the risk of stiffness, tibial component overload, and insert wear.…”

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confidence: 99%

A Total Knee Arthroplasty Is Stiffer When the Intraoperative Tibial Force Is Greater than the Native Knee

2018

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We hypothesized that a total knee arthroplasty (TKA) with an intraoperative tibial force greater than the tibial force of the native knee has signs of stiffness as measured by loss of extension and flexion, and anterior translation of the tibia. Intraoperative forces in the medial and lateral tibial compartments were measured during passive motion in 71 patients treated with calipered kinematically aligned TKA. Maximum extension, flexion, and the anterior–posterior position of the tibia with respect to the distal femur at 90 degrees of flexion were measured. Measurements were repeated after exchanging to a 2 mm thicker insert. The sum of the average of the medial and lateral compartment forces at 0, 45, and 90 degrees of flexion represented the tibial force through a 90-degree motion arc. For the implanted insert, the tibial force averaged 28 ± 17 lb, which is comparable to the 20 ± 7 lb reported for the native knee. At 6 months, patients reported an average 40 point Oxford Knee and 15 point Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score. For the 2 mm thicker insert, the tibial force averaged 50 ± 28 lb. A 30 lb tibial force greater than native generated a 3-degree loss of extension, a 3-degree loss of flexion, and 3-mm anterior translation of the tibia. Because a TKA with a tibial force greater than native has signs of stiffness, a strategy for lowering this risk is to match the tibial force of the native knee when balancing a TKA as this restored high function.

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“…споры о допустимости сохранения остаточного варусного отклонения оси после Тэкс не утихают. одни авторы настаивают на необходимости полной коррекции деформации [3,[6][7][8][9][10][11], другие опровергают ее, демонстрируя отсутствие различий в результатах Тэкс у пациентов с полной…”

Section: Introductionunclassified

Residual Deformity After Bilateral Knee Arthroplasty: Impact on Short Term Outcomes

Зиновьев

Паськов

Sergeev

et al. 2018

Traumatology and Orthopedics of Russia

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Purpose— to evaluate the impact of frontal positioning of prosthesis components after bilateral Tka on short term functional outcomes. Material and Methods. The authors performed a retrospective analysis of teleroentgenograms of 466 patients after bilateral Tka with initial varus deformity. Functional and roentgenological outcomes were evaluated at average in 16,4±2,9 months postoperatively. Mean preoperative varus deformity was 10° (from 5 to 25°), initial angle between the anatomical and mechanical femoral axis (FVa) was 6,7±2° (from 3 to 12°). The neutral axis of both lower limbs (Hka = 180±0,5°) was obtained in 99 (21,2%) out of 466 patients. Residual deformity in one of the limbs above 3° with the neutral alignment of the contralateral limb was observed in 44 (9,4%) patients, bilateral residual deformity – in 32 (6,9%) patients. Other 291 patients demonstrated the deviation from mechanical axis in the range from 1 to 3° (±0,5°). all patients were divided into three groups: first group consisted of 10 patients with neutral axis of one limb and varus deformity of the other limb above 3°; second group — 10 patients with bilateral residual varus deformity above 3°; third group — 12 patients with neutral axis of both limbs (Hka = 180°). The angle of residual deformity averaged 3,7° (from 3,2 to 5,1°).Results.No statistically significant differences between the groups were observed for dynamometric parameters and SF-36 scores, as well as for functional kSS scores (p>0,05). However, the authors reported in patients of the first group a stance phase on the side of residual varus deformity longer at 15% (p<0,05) and transfer phase shorter at 17% (p<0,05) as compared to contralateral limb (with neutral alignment, Hka = 180°), which is indicative of load asymmetry and can have a negative impact at a later stage.Conclusion. Symmetrical residual varus deformity of lower limbs in the rage of 3,2–5,1° has no negative impact of short term clinical and functional outcomes of Tka. Muscular function and gait properties in patients with neutral axis of the lower limbs and in patients with symmetrical residual varus deformity after Tka were similar 16,4±2,9 months postoperatively.

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Leaving Residual Varus Alignment After Total Knee Arthroplasty Does Not Improve Patient Outcomes

Abstract: Findings fail to support the notion that leaving varus knees in residual varus will improve outcomes and pain. Caution is advised when leaving limbs in residual varus after TKA.

Cited by 31 publications

References 49 publications

Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

A Total Knee Arthroplasty Is Stiffer When the Intraoperative Tibial Force Is Greater than the Native Knee

Residual Deformity After Bilateral Knee Arthroplasty: Impact on Short Term Outcomes

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