Ten Flaws of Systematic Mechanical Alignment Total Knee Arthroplasty

Beckers, Gautier; Meneghini, R. Michael; Hirschmann, Michael T.; Kostretzis, Lazaros; Kiss, Marc-Olivier; Vendittoli, Pascal-André

doi:10.1016/j.arth.2023.11.023

Cited by 9 publications

(7 citation statements)

References 67 publications

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“…In mechanical alignment (MA), historically considered the gold standard in total knee arthroplasty (TKA) for decades, the objective was to align all knees to a straight leg axis with a horizontal joint line, although only 15% of natural knees exhibit these characteristics [15]. Hirschmann et al [12] could further show that a huge variability of patient-specific bony phenotypes exists, and most of them would be altered if mechanically aligned [2]. Changing individual bony anatomy into one standard anatomy is considered a relevant factor for limited patient satisfaction after TKA [4,19].…”

Section: Introductionmentioning

confidence: 99%

Tibia‐first, gap‐balanced patient‐specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities

Graichen,

Avram,

Strauch

et al. 2024

Knee surg. sports traumatol. arthrosc.

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PurposeThe present study focuses on testing the capability of a restricted tibia‐first, gap‐balanced patient‐specific alignment technique (PSA) to restore bony morphology and phenotypes.MethodsThree‐hundred and sixty‐seven patients were treated with navigated total knee arthroplasty and tibia‐first gap‐balanced PSA technique. Boundaries for medial proximal tibial angle were 86°–92°, mechanical lateral distal femoral angle 86°–92°, and hip–knee–ankle angle 175°–183°. Knees were classified by coronal plane alignment of the knee (CPAK), with subsequent analyses comparing pre‐ and postoperative distributions. Phenotype classification within CPAK groups assessed pre‐ and postoperative distributions.ResultsPreoperatively, the largest CPAK group was type II (30.8%), followed by type I (20.5%) and type V (17.8%). Postoperatively, type II remained the largest group (39%), followed by type V (30%). All groups with varus/valgus deformities (I, III, IV and VI) became smaller. While in straight legs (II, IV), the CPAK was restored in more than 70%–75%, in varus groups (I, IV) in 40%–50% and in valgus (III and VI) in 5%–18%. The joint line obliquity remained the same in the majority of knees (straight >75%; varus 63%–80%; valgus VI 95%), with the exception of CPAK III (40%). The phenotype analysis showed for straight legs a phenotype restoration of 85%, for varus 94% and for valgus 37%. Joint line convergence angle was reduced significantly in all groups from 1.8°–4.3° preoperatively to 0.6°–1.2° postoperatively.ConclusionPSA restores bony phenotypes and joint line obliquity in the majority of straight and varus knees, while most of the valgus and extreme varus knees are normalised.Level of EvidenceLevel III, retrospective cohort study.

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Section: Introductionmentioning

confidence: 99%

Tibia‐first, gap‐balanced patient‐specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities

Graichen,

Avram,

Strauch

et al. 2024

Knee surg. sports traumatol. arthrosc.

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“…MA fails to account for the significant variability in constitutional lower limb alignment [ 3 , 7 , 17 ]. The utilisation of a general‐purpose, single‐target alignment strategy for all patients (despite historically imperfect outcomes, advances in implant design and understandings of knee motion) is being challenged [ 2 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

Conventionally instrumented inverse kinematic alignment for total knee arthroplasty: How is it done?

Russell,

Keyes,

Hirschmann

et al. 2024

J. exp. orthop.

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PurposeFor primary total knee arthroplasty (TKA), there is an increasing trend towards patient‐specific alignment strategies such as kinematic alignment (KA) and inverse kinematic alignment (iKA), which by restoring native joint mechanics may yield higher patient satisfaction rates. Second, the most recent Australian joint registry report describes favourable revision rates for conventionally instrumented TKA compared to technology‐assisted techniques such as those using navigation, robotics or custom‐cutting blocks. The aim of this technique article is to describe in detail a surgical technique for TKA that: (1) utilises the principles of iKA and (2) uses conventionally instrumented guided resections thereby avoiding the use of navigation, robotics or custom blocks.MethodsA TKA technique is described, whereby inverse kinematic principles are utilised and patient‐specific alignment is achieved. Additionally, the patellofemoral compartment of the knee is restored to the native patellofemoral joint line. The sequenced technical note provided may be utilised for cemented or cementless components; cruciate retaining or sacrificing designs and for fixed or rotating platforms.ResultsAn uncomplicated, robust and reproducible technique for TKA is described.DiscussionKnee arthroplasty surgeons may wish to harness the emerging benefits of both a conventionally instrumented technique and a patient‐specific alignment strategy.Level of EvidenceLevel V.

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“…Coronal alignment in total knee arthroplasty (TKA) has been the main focus of knee arthroplasty surgeons since the commercial beginnings of knee arthroplasty [9,18]. Placing the implants parallel to the ground, mechanical alignment (MA) is arguably still the 'gold standard' due to a long track record of good and predictable outcomes [2,8]. Kinematic alignment (KA) has challenged this philosophy, where implants are oriented according to the patient anatomy in three kinematic axes [15].…”

Section: Introductionmentioning

confidence: 99%

The effect of different alignment strategies on trochlear orientation after total knee arthroplasty

Klasan,

Anelli‐Monti,

Putnis

et al. 2024

Knee surg. sports traumatol. arthrosc.

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PurposeWhen planning and delivering total knee arthroplasty (TKA), there are multiple coronal alignment strategies such as functional alignment (FA), kinematic alignment (KA), mechanical and adjusted mechanical alignment (MA, aMA). Recent three‐dimensional and robotic‐assisted surgery (RAS) studies have demonstrated that KA potentially better restores the trochlear anatomy than MA. The purpose of this study was to compare the restoration of the native trochlear orientation in patients undergoing RAS TKA using four different alignment strategies. It was hypothesised that FA would result in the lowest number of outliers.MethodsThis is a prospective study of 200 patients undergoing RAS‐TKA with a single implant. All patients were analysed for MA and KA prebalancing, and 157 patients received aMA and 43 patients FA with intraoperative balancing. Preoperative transverse computed tomography scans were used to determine the posterior condylar axis (PCA), lateral trochlear inclination (LTI) angle, sulcus angle (SA) and anterior trochlear line (ATL) angle. Implant measurements were obtained using a photographic analysis. Intraoperative software data combined with implant data and preoperative measurements were used to calculate the differences. Outliers were defined as ≥3° of alteration. Trochlea dysplasia was defined as LTI < 12°.ResultsNative transepicondylar PCA had a median of 2°, LTI 18°, SA 137°, ATL 4°. LTI outliers were observed in 47%–60% of cases, with KA < FA < aMA < MA. For ATL, the range of outliers was 40.5%–85%, KA < FA < aMA < MA. SA produced 81% of outliers. Of all median angle values, only LTI when using KA was not significantly altered compared to the native knee.ConclusionThere is a significant alteration of trochlear orientation after TKA, regardless of the alignment strategy used. KA produced the lowest, but a substantial, number of outliers. The uniform design of implants causes the surgeon to compromise on balance in flexion versus trochlear position. The clinical relevance of this compromise requires further clinical investigations.Level of EvidenceLevel II, prospective cohort study.

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Ten Flaws of Systematic Mechanical Alignment Total Knee Arthroplasty

Cited by 9 publications

References 67 publications

Tibia‐first, gap‐balanced patient‐specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities

Tibia‐first, gap‐balanced patient‐specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities

Conventionally instrumented inverse kinematic alignment for total knee arthroplasty: How is it done?

The effect of different alignment strategies on trochlear orientation after total knee arthroplasty

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