Evidence map›Paper›PMID 33517740›Full record

Trial reportThe bone & joint journal2021

Coronal Plane Alignment of the Knee (CPAK) classification.

Samuel J MacDessi, William Griffiths-Jones, Ian A Harris, Johan Bellemans, Darren B Chen

Erratum issued 2 registry-linked trialsOpen access · hybridAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in The bone & joint journal, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. It is linked to 2 registered trials, which are not on this map. Cited by 331 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
331citing papers in PubMed, 5 pooled it
64.6field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT06726993 nanot yet recruitingnot on this mapstarted 2025, after this paper: background citation

Comparison of Restricted Kinematic Alignment Versus Unrestricted Kinematic Alignment in Primary Total Knee Arthroplasty:- Randomized Controlled Trial

TypeinterventionalSponsorAssiut UniversityRan2025 to 2027Enrolled80ConditionsOsteoarthritis (OA) of the Knee, Total Knee AnthroplastyArmsTotal knee arthroplasty
NCT07574775 nacompletednot on this mapstarted 2025, after this paper: background citation

Is It Possible to Obtain Reliable MPTA and LDFA Values Using Imageless Navigation in Total Knee Arthroplasty? Comparison Between Preoperative CT Scan Measurements and Intraoperative Bone Morphing Before and After Articular Cartilage Removal.

TypeinterventionalSponsorGroupe Hospitalier Diaconesses Croix Saint-SimonRan2025 to 2025Enrolled50ConditionsArthroplasty, Bone Morphing, Knee OsteoarthritisArmsNon-image-based Computer-Assisted Navigation with Bone Morphing
3 · Its place in the literature

Who cites it

331 citing papers in PubMed, 5 syntheses or guidelines pooled it, 570 citations in OpenAlex.

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271 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors at 4 institutions in 3 countries.

Samuel J MacDessiCPAK Research Group, Sydney, Australia.ORCID https://orcid.org/0000-0002-1578-7614
William Griffiths-JonesCPAK Research Group, Sydney, Australia.
Ian A HarrisOrthopaedic Surgery, University of New South Wales, South Western Sydney Clinical School, Liverpool, NSW, Australia.
Johan BellemansCPAK Research Group, Sydney, Australia.
Darren B ChenCPAK Research Group, Sydney, Australia.
UNSW Sydney · AUHasselt University · BENorth Devon District Hospital · GBSt George Hospital · AU

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

aimsA comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA).

methodsA radiological analysis of 500 healthy and 500 osteoarthritic (OA) knees was used to assess the applicability of the CPAK classification. CPAK comprises nine phenotypes based on the arithmetic HKA (aHKA) that estimates constitutional limb alignment and joint line obliquity (JLO). Intraoperative balance was compared within each phenotype in a cohort of 138 computer-assisted TKAs randomized to KA or MA. Primary outcomes included descriptive analyses of healthy and OA groups per CPAK type, and comparison of balance at 10° of flexion within each type. Secondary outcomes assessed balance at 45° and 90° and bone recuts required to achieve final knee balance within each CPAK type.

resultsThere was similar frequency distribution between healthy and arthritic groups across all CPAK types. The most common categories were Type II (39.2% healthy vs 32.2% OA), Type I (26.4% healthy vs 19.4% OA) and Type V (15.4% healthy vs 14.6% OA). CPAK Types VII, VIII, and IX were rare in both populations. Across all CPAK types, a greater proportion of KA TKAs achieved optimal balance compared to MA. This effect was largest, and statistically significant, in CPAK Types I (100% KA vs 15% MA; p < 0.001), Type II (78% KA vs 46% MA; p = 0.018). and Type IV (89% KA vs 0% MA; p < 0.001).

conclusionCPAK is a pragmatic, comprehensive classification for coronal knee alignment, based on constitutional alignment and JLO, that can be used in healthy and arthritic knees. CPAK identifies which knee phenotypes may benefit most from KA when optimization of soft tissue balance is prioritized. Further, it will allow for consistency of reporting in future studies. Cite this article:

Indexed as

Arthroplasty, Replacement, KneeAdultAgedAged, 80 and overBiomechanical PhenomenaBone MalalignmentCase-Control StudiesFemaleHumansKnee JointMaleMiddle AgedOsteoarthritis, KneePerioperative CarePostural BalanceProspective StudiesArithmetic HKAConstitutional alignmentCoronal Plane Alignment Knee classificationCPAKJoint line obliquityKinematic alignmentKnee alignment

Identifiers

PMID33517740
PMCPMC7954147
OpenAlexW3126587127

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.