The document discusses the importance of understanding normal limb alignment and joint orientation in the treatment of skeletal deformities. It outlines methods for assessing both mechanical and anatomic axes of bones, as well as joint center points and orientation lines for various joints in the body. Furthermore, it describes the angles and distances relevant to joint orientation and alignment, emphasizing the need to analyze these parameters through radiographic imaging.

1. NORMAL LIMB
ALIGNMENT AND JOINT
ORIENTATION
Prepared by: Supervised by:
Dr. Abdullah K. Ghafour Dr. Hamid Ahmed Jaff
3rd year IBFMS trainee

2. Introduction
 The treatment of skeletal deformity is the
heart of our specialty. Indeed, the very
name of our specialty, ORTHOPAEDICS,
was coined by Nicholas Andry in 1741 as
a word derived from two Greek words,
orthos (meaning straight) and paedis
(meaning child) to indicate his goal "to
teach the different methods of preventing
and correcting deformities of children" .
(from Mercer Rang's Anthology of Orthopaedics,
1966)

3. Introduction
 [ It is not hard to learn, but it does take some effort and
practice. The method is mercifully low-tech: the only
tools required are a pencil, ruler, and goniometer.]
DROR PALEY MD,FRCSC

4. Introduction
 The exact anatomy of the bones and joints is of great
importance to the clinician when examining the limbs
and to the surgeon when operating on the bones and
joints.
 To understand deformities of the extremities, it is
important to first understand and establish the
parameters and limits of normal alignment.
 Each long bone has a mechanical and an anatomic axis
 both frontal and sagittal planes axis lines are applicable
to any longitudinal projection of a bone.
 The corresponding radiographic projections are the
anteroposterior (AP) and lateral (LAT) views,
respectively.

5. Mechanical axis
 It is defined as the straight line connecting the joint
center points of the proximal and distal joints.
 The mechanical axis is always a straight line, whether in
the frontal or sagittal plane.

6. Anatomic axis
 The anatomic axis of a bone is the mid-diaphyseal line.
 The anatomic axis line may be straight in the frontal
plane but curved in the sagittal plane, as in the femur.

7. Joint Center Points
 It is the point of any joint which the mechanical axis
passes through in frontal plane.
 For the hip, the joint center point is the center of the
circular femoral head.
Mose circles goniometer

8. Joint Center Points
 the center of the knee joint is approximately the same
using these points:
 The ankle joint center point is the same using these
points:

9. Joint Orientation Lines
 line which represent the orientation of a joint in a
particular plane or projection.
 At the ankle, the joint orientation line in the frontal plane
is drawn across the flat subchondral line of the tibial
plafond. In the sagittal plane the line is drawn across the
distal tips of both lips of the tibia.
frontal plane sagittal plane

10. Joint Orientation Lines
 The frontal plane knee joint line of the proximal tibia is
drawn across the subchondral line of the two tibial
plateaus.
 In the sagittal plane, the proximal joint line of the tibia is
drawn along the flat subchondral line of the plateaus
frontal plane sagittal plane

11. Joint Orientation Lines
 The frontal plane knee joint orientation line of the distal
femur is drawn as a line tangential to the most distal
points on the convexity of the two femoral condyles
 In the sagittal plane, the distal femoral joint orientation
line drawn as a straight line connecting the two points
where the femoral condyles meet the metaphysis of the
femur.
frontal plane sagittal plane

12. Joint Orientation Lines
 A line from the proximal tip of the greater trochanter to
the center of the femoral head represents the hip joint
orientation line of the hip joint in the frontal plane.
 Alternatively, the mid-diaphyseal line of the femoral
neck can represent the orientation of the hip joint.
hip joint orientation line

13. Joint Orientation Angles
 The angle formed between the joint line and either the
mechanical or anatomic axis. each axis line and joint
orientation line intersection forms two angles. Either
angle could be named with this nomenclature.
 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]).

14. Joint Orientation Angles
 Therefore, 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.
 Similarly, the anatomic LDFA (aLDFA) is the lateral
angle formed between the anatomic axis of the femur
and the knee joint line of the femur in the frontal plane.

15. Joint Orientation Angles
frontal plane-mechanical frontal plane-anatomical sagittal plane-anatomical

16. Joint Orientation Angles
 The angle formed between joint
orientation lines on opposite sides
of the same joint is called the joint
line convergence angle (JLCA)
 In the knee and ankle joints, these
lines are normally parallel.

17. Joint Orientation Angles
 In the frontal plane, the
distance between the
intersection of the anatomic
axis line with the joint center
point is called the anatomic
axis to joint center distance
(aJCD)
 the anatomic axis: joint
center ratio (aJCR) is the
ratio of the aJCD and the
total width of the joint.

18. Joint Orientation Angles
 In the sagittal plane, the
distance between the point of
intersection of the anatomic
axis line with the joint line and
the anterior edge of the joint is
called the anatomic axis to
joint edge distance (aJED).
 The anatomic axis: joint edge
ratio (aJER) is the ratio
between the aJED and the
total width of the joint.

19. Alignment and Orientation
 In the frontal plane, the
line passing from the
center of the femoral head
to the center of the ankle
plafond is called the
mechanical axis of the
lower limb.
 There are two
considerations when
evaluating the frontal
plane of the lower
extremity: joint alignment
and joint orientation.

20. Alignment and Orientation
 Alignment refers to the
collinearity of the hip, knee,
and ankle
 Orientation refers to the
position of each articular
surface relative to the axes of
the individual limb segments
(tibia and femur)
 Alignment and orientation are
best judged using long
standing AP radiographs of the
entire lower extremity on a

21.  malalignment occurs when
the center of the joint does
not lie close to mechanical
axis line.
 The distance between the
mechanical axis line and the
center of the knee in the
frontal plane is the MAD.
 The MAD is described as
either medial (varus) or
lateral (valgus) MADs.
Alignment and Orientation

22. Alignment and Orientation
 Mechanical tibiofemoral angle
(1.3 ± 2° varus ) or anatomical
(tibiofemoral angle (6° ± 2°
valgus) also can be use for
evaluating knee joint
alignment

23. Alignment and Orientation
 hip joint orientation can be evaluated by using the
neck shaft angle (MNSA)125°-131°. Or lateral
proximal femoral angle (LPFA) 89.9° ± 5.2°
frontal plane

24.  In knee joint mechanical lateral distal femoral angle
(mLDFA = 87.8°±1.6° valgus) is used for evaluating
distal femoral knee joint orientation in the frontal plane.
 To consider the proximal tibial joint orientation in the
frontal plane mechanical medical proximal tibial angle
(MPTA = 87.2°±1.5° varus)
Alignment and Orientation
frontal plane

25.  In the sagittal plane (PDFA
= 83.1±3.6°) is used for
evaluating distal femoral
knee joint orientation. And
(PPTA = 80.4± 1.6°) for
evaluating proximal tibial
knee joint orientation
Alignment and Orientation
sagittal plane

26. Alignment and Orientation
 The normal frontal plane joint line orientation of the
ankle is slight valgus using (LDTA = 88.6 ± 3.8°) and the
normal sagittal plane joint line orientation of the ankle
has anterior tilt of the distal tibia using ( ADTA = 79.8±
1.6°)
frontal plane sagittal plane

27. ?
THANK