Optimal Flexion for the Femoral Component in TKR: A Study of Angle Between Mechanical Axis and Distal Anatomic Intramedullary Axis Using 3D Reconstructed CT Scans in 407 Osteoarthritic Knees Studied in India

Shah, Manish R; Patel, Jil P; Patel, Chirag

doi:10.1007/s43465-020-00106-6

Cited by 2 publications

(2 citation statements)

References 19 publications

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“…The amount of distal femoral resection needed to restore the original joint line was determined. The degree of femoral component flexion was set to 2° to avoid anterior femoral notching [4, 19, 24]. The size of the femoral component was determined with reference to the native anteroposterior length of the lateral femoral condyle.…”

Section: Methodsmentioning

confidence: 99%

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle

Song

Lee

Bae³

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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PurposeTo analyze the incidence of intraoperative mid‐flexion laxity using continuous flexion‐arc gap assessment, risk factors for mid‐flexion laxity, and clinical results in navigation‐assisted total knee arthroplasty (TKA). MethodsNinety posterior‐stabilized TKAs were performed under navigation guidance for patients with degenerative arthritis and varus deformity. Intraoperatively, the gap between the trial femoral component and insert was evaluated in the navigation system with continuous flexion‐arc gap assessment. Each medial and lateral gap at flexion (90°) and extension (0°) were made to be less than 3 mm. Mid‐flexion laxity was determined when the gap in the flexion range between 15° and 60° was 3 mm or more. The proportion of knees with mid‐flexion laxity was investigated. The factors affecting mid‐flexion laxity were identified in terms of demographics, preoperative convergence angle, and change in joint line height and posterior femoral offset. The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index were evaluated. ResultsThere were 31 cases (34.4%) of lateral mid‐flexion laxity (average peak mid‐flexion gap = 3.7 mm). The other 59 cases did not show mid‐flexion laxity. The preoperative convergence angle was the only significant factor affecting lateral mid‐flexion laxity (odds ratio = 1.466, p = 0.002). There were no significant differences in the clinical results between the groups with and without mid‐flexion laxity. ConclusionsThe continuous flexion‐arc gap assessment was useful in evaluating mid‐flexion laxity using navigation‐assisted TKA. The preoperative convergence angle, reflecting soft‐tissue laxity, can be a practical and simple radiographic finding for predicting lateral mid‐flexion laxity. Level of evidenceIV.

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Section: Methodsmentioning

confidence: 99%

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle

Song

Lee

Bae³

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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“…Optimal positioning of the femoral component in the sagittal plane has not yet been defined [ 13 , 14 ]. Surgeons using navigation, for sagittal positioning of femoral component, continue to make the distal femoral cut perpendicular to SMX [ 8 , 9 ], although studies have shown that this can increase the risk of notching in navigated TKA [ 6 , 12 ]. The present study intends to determine, by opting to place the femoral component perpendicular to DCX rather than perpendicular to SMX, if one can reduce the incidence and depth of notching in navigated TKA.…”

Section: Discussionmentioning

confidence: 99%

Notching is less, if femoral component sagittal positioning is planned perpendicular to distal femur anterior cortex axis, in navigated TKA

Kanna¹,

Ravichandran²,

Shetty

2021

Knee Surg & Relat Res

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Purpose In navigated TKA, the risk of notching is high if femoral component sagittal positioning is planned perpendicular to the sagittal mechanical axis of femur (SMX). We intended to determine if, by opting to place the femoral component perpendicular to distal femur anterior cortex axis (DCX), notching can be reduced in navigated TKA. Methods We studied 171 patients who underwent simultaneous bilateral computer-assisted TKA. Femoral component sagittal positioning was planned perpendicular to SMX in one knee (Femur Anterior Bowing Registration Disabled, i.e. FBRD group) and perpendicular to DCX in the opposite knee (Femur Anterior Bowing Registration Enabled, i.e. FBRE group). Incidence and depth of notching were recorded in both groups. For FBRE knees, distal anterior cortex angle (DCA), which is the angle between SMX and DCX, was calculated by the computer. Results Incidence and mean depth of notching was less (p = 0.0007 and 0.009) in FBRE versus FBRD group, i.e. 7% versus 19.9% and 0.98 mm versus 1.53 mm, respectively. Notching was very high (61.8%) in FBRD limbs when the anterior bowing was severe (DCA > 3°) in the contralateral (FBRE) limbs. Conclusion Notching was less when femoral component sagittal positioning was planned perpendicular to DCX, in navigated TKA. Level of evidence Therapeutic level II.

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Optimal Flexion for the Femoral Component in TKR: A Study of Angle Between Mechanical Axis and Distal Anatomic Intramedullary Axis Using 3D Reconstructed CT Scans in 407 Osteoarthritic Knees Studied in India

Cited by 2 publications

References 19 publications

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle

Mid-flexion laxity could be identified with continuous flexion-arc gap assessment in patients with a large preoperative convergence angle

Notching is less, if femoral component sagittal positioning is planned perpendicular to distal femur anterior cortex axis, in navigated TKA

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