Evidence map›Paper›PMID 41392281›Full record

ArticleArthroplasty (London, England)2025

Beyond valgus stress radiography: arithmetic HKA angle (aHKA) as a superior predictor of limb alignment after UKA.

Naoki Nakano, Masanori Tsubosaka, Tomoyuki Kamenaga, Yuichi Kuroda, Kazunari Ishida, Shinya Hayashi, Ryosuke Kuroda, Tomoyuki Matsumoto

Abstract read
In one paragraph

Article in Arthroplasty (London, England), 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

8 authors.

Naoki NakanoDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan. gnaokix1981@gmail.com.
Masanori TsubosakaDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
Tomoyuki KamenagaDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
Yuichi KurodaDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
Kazunari IshidaDepartment of Orthopaedic Surgery, Kobe Kaisei Hospital, 3-11-15, Shinoharakita-Machi, Nada-Ku, Kobe, Hyogo, 657-0068, Japan.
Shinya HayashiDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
Ryosuke KurodaDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.
Tomoyuki MatsumotoDepartment of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, Hyogo, 650-0017, Japan.

Funding

Takeda Science Foundation 2022
6 · The paper itself

Abstract

purposeAccurate prediction of postoperative coronal alignment is essential for successful outcomes following medial unicompartmental knee arthroplasty (UKA). Traditionally, valgus stress femorotibial angle (FTA) has been used to estimate the correctability of varus deformity; however, its reliability is limited by dependence on soft tissue behavior and examiner technique. In contrast, the arithmetic hip-knee-ankle angle (aHKA), calculated from bony anatomy, offers an objective and reproducible measure of constitutional limb alignment. While early studies suggest aHKA correlates well with postoperative alignment, direct comparison with valgus stress FTA has been lacking. This study aimed to compare the predictive accuracy of aHKA and valgus stress FTA for postoperative alignment and alignment correction (ΔHKA) in medial UKA.

methodsThis retrospective study included 125 knees undergoing medial fixed-bearing UKA. Preoperative aHKA was calculated from long-leg radiographs, and valgus stress FTA was measured using a Telos arthrometer. Postoperative hip-knee-ankle angle (HKA) was obtained from standardized radiographs. Correlation analyses were performed between postoperative HKA and both aHKA and 360°-valgus stress FTA. Similarly, correlations were assessed between ΔHKA and (aHKA-preoperative HKA) as well as (360°-valgus stress FTA-preoperative HKA). Fisher's Z-test was used to assess differences in correlation strengths.

resultsPostoperative HKA showed stronger correlation with aHKA (R

conclusionaHKA demonstrated superior predictive accuracy for both postoperative alignment and alignment correction compared to valgus stress FTA. As a bone-based and examiner-independent parameter, aHKA is a valuable tool for preoperative planning in medial UKA and may reduce the need for stress radiography. Video Abstract.

Indexed as

Arithmetic hip-knee-ankle angleCoronal alignmentFemorotibial angleUnicompartmental knee arthroplastyValgus stress radiograph

Identifiers

PMID41392281
PMCPMC12703935

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