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Part of Deformity Correction Of Lower Limb Bones
Type Medical knowledge page
Keywords Orthopedic Surgery, Complex Bone Deformity, Lower-limb, Surgical Training, Surgical Simulation, X-ray planning, 3D Printing, Cloud software
SDG Sustainable Development Goals SDG03 Good health and well-being
Authors Amit Dinanath Maurya
OpenSurgiSim
Published 2021
License CC-BY-SA-4.0
Affiliations AlgoSurg Inc
Mangal Anand Hospital (Mumbai)
Global Surgical Training Challenge
Language English (en)
Impact Number of views to this page. Views by admins and bots are not counted. Multiple views during the same session are counted as one. 116

The joint lines in the frontal and sagittal planes have a characteristic or well-defined orientation to the mechanical and anatomic axes. This is defined as Joint Orientation Angles.

The name of each angle specifies whether it is measured relative to a mechanical (m) or an anatomic (a) axis. The angle may be measured medial (M), lateral (L), anterior (A), or posterior (P) to the axis line. The angle may refer to the proximal (P) or distal (D) joint orientation angle of a bone (femur [F] or tibia [T]).

The schematic drawings of the nomenclature of the mechanical and anatomical frontal and sagittal joint angles and their normal ranges are described in the below figures (Fig. 5a, 5b and 5c)

Video Summary[edit | edit source]

Annotations:
  • 26:50 LPFA
  • 27:44 mLDFA
  • 28:20 JLCA
  • 30:15 MPTA
  • 30:30 LDTA
  • 31:00 MPFA
  • 31:32 MNSA
  • 32:00 aLDFA

Mechanical joint angles[edit | edit source]

Fig. 5a. Diagram of mechanical joint angles, with nomenclature and normal ranges.

The mechanical lateral distal femoral angle (mLDFA) is the lateral angle formed between the mechanical axis line of the femur and the knee joint line of the femur in the frontal plane.

The lateral proximal femoral angle (LPFA) is the lateral angle formed between the mechanical axis line of the femur and the proximal joint line of the femur in the frontal plane

The medial proximal tibial angle (MPTA) is the medial angle formed between the mechanical axis or anatomic axis line of the tibia and the knee joint line of the tibia in the frontal plane.

The lateral distal tibial angle (LDTA) is the lateral angle formed between the mechanical axis or anatomic axis line of the tibia and the distal joint line of the tibia in the frontal plane.

The joint line convergence angle (JLCA) is the angle formed between the femoral distal joint line and tibial proximal joint line in the frontal plane

Anatomical frontal angles[edit | edit source]

Fig. 5b. Diagram of anatomical frontal joint angles, with nomenclature and normal ranges.

The anatomic lateral distal femoral angle (aLDFA) is the lateral angle formed between the anatomical axis line of the femur and the knee joint line of the femur in the frontal plane.

The medial proximal femoral angle (MPFA) is the medial angle formed between the anatomical axis line of the femur and the proximal joint line of the femur in the frontal plane.

The medial neck shaft angle (MNSA) is the medial angle formed between the anatomical axis line of the proximal femur and the neck axis of the femur in the frontal plane.

Anatomical sagittal angles[edit | edit source]

Fig. 5c. Diagram of anatomical sagittal joint angles, with nomenclature and normal ranges.

The posterior distal femoral angle (PDFA) is the posterior angle formed between the anatomical axis line of the distal femur and the distal joint line of the femur in the sagittal plane.

The posterior proximal tibial angle (PPTA) is the posterior angle between the anatomic axis of the tibia and the proximal  joint line of the tibia in the sagittal plane

The anterior distal tibial angle (ADTA) is the anterior angle between the anatomic axis of the tibia and the distal joint line of the tibia in the sagittal plane.