n., plural: valguses
Definition: Outwardly turned bone
Table of Contents
Valgus means “outwardly turned bone”. ‘Valgus’ refers to anatomical bone deformity wherein a part of the bone turns at an abnormal outwardly angle from the sagittal plane of the body or away from the center of the body. Depending upon the part of the body involved, e.g., it can be valgus knee (involves knee joint and is a lower leg deformity), cubitus valgus (involves arm), hallux valgus (involves the big toe), etc.
In a valgus deformity, the distal end of the bone turns in the lateral direction or outer direction. The term ‘valgus’ is often confused with a closely related term ‘varus’. The term ‘var’ refers to anatomical bone deformity wherein a part of the bone turns at an abnormal angle, towards the center of the body.
Bone tissue remodeling and contraction or elongation of the soft tissue results in valgus deformity. Thus, both ‘valgus’ and ‘varus’ the abnormal angulation of the bone, which may either occur in the shaft of the bone or at the joints.
Depending upon the angulation of the distal part of the bone, it could be either valgus or varus. When the distal part of the bone is predominantly bending laterally, then the condition is valgus, while, in the case when the distal part of the bone is largely bending medially, then the condition is varus.
Accordingly, the joints in the valgus would be bending medially as the distal bone is pointing more laterally while in the varus, the joints would be in a lateral position as the distal part of the bone would be pointing or joint medially. This can be easily understood diagrammatically represented in Figure 1.
A mnemonic to remember the difference between Valgus and Varus- Valgus contains the letter ‘L’ in which ‘L’ateral deviation occurs.
Valgus vs Varus
Based on the above discussion we can now differentiate between Valgus and Varus bone abnormalities. (Table 1)
Table 1: Valgus vs Varus Bone Abnormalities
|Bone deformity wherein the distal part of the bone abnormally bends outward or laterally.
|Bone deformity wherein the distal part of the bone abnormally bends inwards in the medial direction.
|In physical examination, a valgus knee abnormality looks like the letter ‘X’
|In physical examination, a varus knee abnormality looks like the letter ‘O’
|Valgus knees are also referred to as ‘Knocked Knees’
|Varus knees are referred to as ‘Bow legs’
|In the case of valgus knees, when both the lower limb or legs are placed together, the knees will touch each other while the ankles remain apart.
|In the case of varus knees, when both legs are placed together, the knees remain wide apart while the ankles touch each other.
|The load-bearing axis of the body shifts laterally, i.e. outside or away from the center of the body resulting in more pressure toward the lateral knee compartment
|The load-bearing axis shifts towards the inner side resulting in stress or pressure on the medial knee compartment
|Herein, the lateral meniscus is affected
|Herein, the medial meniscus is affected
The term “valgus” is the deformity involving oblique displacement of part of a limb away from the midline. Valgus is an anatomical bone deformity wherein a part of the bone bends laterally away from the center of the body. It is a medical term used to refer to the outward angulation of the distal segment of a bone or joint. It should not be confused with the other related term varus, which pertains to the inward deviation of the distal bone towards the midline. An example of valgus deformities is pes valgus, which is an eversion of the foot at the talocalcaneal or subtalar joint. It is usually combined with a breaking down of the plantar arch. Another example is valgus knees where knees bend laterally. Hallux valgus big toe bends outward causing a bunion. Outwardly pointing bone is a valgus deformity.
Etymology: Latin valgus (bent outward).
Types of Valgus Deformity
The proximal part of the bone is used as a reference point and the angle of deformity is with reference to the angle in the normal condition which may or may not be zero. The knee alignment is measured with the help of the valgus angle or Q angle (Figure 2). Depending upon the knee angle of deformity (also referred to as valgus angle or Q angle), the valgus deformity can be of three types:
- Type I– wherein the axial deviation ranges between 6º-10º i.e, valgus angle equal to or less than 10º. This is seen in almost 80% of the cases and can be corrected passively by lateral soft tissue contracture without elongating the medial collateral ligament.
- Type II– wherein the axial deviation ranges between 10º-20º. This is seen in almost 15% of the cases. This deformity can be corrected by lateral soft tissue contracture and elongating the medial collateral ligament.
- Type III– wherein the axial deviation is >20º. This is seen in 5% of the cases. In such cases, lateral structures are tight and have non-functional medial stabilizers.
Three types or grades of valgus deformity are shown in Figure 3.
Here it is important to note that the higher the angle of deformity is, the higher the instability that needs to be corrected.
Knee Arthritis with Valgus Knee
Some of the major causes of valgus knees are:
- Genetic predisposition
- Developmental anomaly
- Injury or fracture of the tibial plateau during childhood
- Infection that resulted in abnormal bone growth
- The metabolic disease of bone
- Deficiency of Vitamin D or extreme vitamin deficiency resulting in rickets
- Knee arthritis
Thus, knee osteoarthritis is one of the major factors resulting in the valgus knee. This condition is characterized by extreme knee pain and instability. Valgus knee is also referred as genu valgum. Knee arthritis with the valgus knee is a condition wherein the valgus angle or Q angle is > 10º.
This condition is a surgical challenge that needs to be corrected during total knee arthroplasty (TKA) [also known as total knee replacement] and is seen in almost 10% of the patients that undergo TKA.
Patients with knee arthritis along with severe valgus deformity are at higher risk of loss of joint space and damage of lateral cartilage at the joints.
Continuous bone tissue remodeling and soft tissue elongation/contraction in knee arthritis results in valgus knee deformity in such patients.
Some of the major bone tissue remodelings include the erosion of lateral cartilage, hypoplasia of lateral femoral condyle and metaphyseal femur, and remodeling of the tibial plateau.
The lateral collateral ligament, popliteus tendon, hamstring tendons, posterolateral capsule, iliotibial band, and lateral head of the gastrocnemius are some of the soft tissues that undergo either contraction or elongation resulting in valgus knees. Valgus knee in osteoarthritis results in misalignment of the knee laterally.
Treatment of knee arthritis with valgus knee involves physical therapy for strengthening knee and hip muscles & proper alignment, using a resistance band. Although, in a majority of cases, valgus deformity in arthritis is corrected by knee bone joint surgery or knee replacement. Prior to surgery, the extent of valgus alignment deformity is measured by estimating the hip-knee-ankle angle.
Some examples of valgus deformities are:
Table 2: Examples of Valgus Deformities
|Valgus knee or genu valgum or knock knee
|The distal part of the tibia is laterally bending or pointing
Figure 4: Valgus knees. Image Credit: Mark.
|Big toe bending outward and pointing towards the second toe, which results in bunion formation
Figure 5: Hallux valgus. Image Credit: Whitney Lowe.
|The forearm bends outward, away from the body
Figure 6: Cubitus valgus. Image Credit: Elite Defence Academy.
|Heel turning outward
Figure 7: Talipes valgus. Image Credit: MedicoApps.
|Turning the foot inside out at the subtalar joint results in a flat foot
Figure 8: Comparative image of the normal foot and Flat foot or Pes valgus. Image Credit: Boyner clinic.
|Femur turns outward at an angle >140º
Figure 9: Coxa valga. Image Credit: Mobile Physiotherapy Clinic.
|Radial club deformity of hand at the wrist
|A genetic deformity wherein wrist bones don’t develop properly
Watch this vid about valgus:
Knock knees or valgus knees are commonly seen in infants/toddlers/pre-schoolers. Axial deformity in children is prominent till the age of 3 years however by the age of 7-8 years it resolves on its own. Also, it is more common in girls as compared to boys.
Take the Vagus – Biology Quiz!
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- Mullaji, A., Bhoskar, R., Singh, A., & Haidermota, M. (2022). Valgus arthritic knees can be classified into nine phenotypes. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 30(9), 2895–2904. https://doi.org/10.1007/s00167-021-06796-1
- Suardi, C., Stimolo, D., Zanna, L., Carulli, C., Fabrizio, M., Civinini, R., & Innocenti, M. (2022). Varus morphology and its surgical implication in osteoarthritic knee and total knee arthroplasty. Journal of orthopaedic surgery and research, 17(1), 299. https://doi.org/10.1186/s13018-022-03184-4
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