Acta chirurgiae orthopaedicae
et traumatologiae Čechoslovaca

Acta Chir Orthop Traumatol Cech. 2022; 89(5):344-348 | DOI: 10.55095/achot2022/055

The Association between Constitutional Knee Alignment and the Horizontal Orientation of the Ankle Joint LineOriginal papers

C. KONRADS^1,2,*, S. DÖBELE², A. EIS², U. STÖCKLE³, S. S. AHMAD^2,4

¹ Department of Orthopaedic Surgery, University of Tübingen, Tübingen, Germany

² Department of Trauma and Reconstructive Surgery, BG Klinik, University of Tübingen, Tübingen, Germany

³ Center for Musculoskeletal Surgery, Charité - University Medical Center Berlin, Berlin, Germany

⁴ Department of Orthopaedic Surgery, Hannover Medical School, Hannover, Germany

PURPOSE OF THE STUDY:
To characterize constitutional frontal alignment of the ankle in genua vara, valga, and norma.

MATERIAL AND METHODS:
Long-leg standing radiographs of 589 patients presenting between 2011 and 2020 for knee-complaints because of any reason were chosen from our database. Cases with fractures or history of bony-realignment-surgeries were excluded. The Hip-Knee-Ankle angle (HKA), the mechanical Lateral Distal Tibia Angle (mLDTA), and the Tibia-Plafond-Horizontal-Orientation angle (TPHA) were measured in 354 patients. For this study, neutral frontal alignment of the leg was defined as HKA between -3.0° and +4.0°. HKA-values 4.0° were defined as genua vara. According to these cutoffs, data was categorized into the following three patient groups: genua vara (n=157), genua norma (n=106), genua valga (n=91). For each group, the ankle alignment in the frontal plane was compared to the HKA. Finally, the three groups were compared to each other.

RESULTS:
In the varus-group, the HKA-value was 6.9°±2.4°, the TPHA-value was 4.7°±3.5°, and the mLDTA-value was 87.4°±4.8°. In the neutral-group, the HKA-value was 1.8°±2.0°, the TPHA-value was 2.5°±2.9°, and the mLDTA-value was 87.2°±4.6°. In the valgus-group, the HKA-value was -6.0°±2.7°, the TPHA-value was -0.2°±4.7°, and the mLDTA-value was 85.0°±4.7°.

DISCUSSION:
The frontal alignment of the ankle joint line depends on the overall frontal alignment of the leg. The TPHA correlates with varus or valgus alignment of the knee, but the mLDTA does not. In patients with valgus-aligned long-leg axis, the TPHA demonstrated less valgus alignment than in patients with varus-aligned long-leg axis. This knowledge is especially useful when planning osteotomies for correction of lower extremity malalignment.

CONCLUSIONS:
During the planning process of osteotomies around the knee, the TPHA should be appreciated because it correlates with the constitutional knee alignment.

Keywords: valgus, varus, frontal alignment, coronal alignment, osteotomy

Published: October 15, 2022  Show citation