Cubitus Varus is called when the forearm has deviated inwards with respect to the arm at the elbow resulting in medial angulation in full extension.
Any reduction in physiological valgus is called cubitus varus (Even cubitus rectus is cubitus varus)
Normal Values: 8°-15°
Higher in females
Lower in males
Causes:
- Progressive Varus
- Congenital (Progressive)
- Mal-united lateral condyle fracture ( Progressive if due to hyperemia and overgrowth)
- Static Varus
- Supracondylar fracture malunited
- Trochlear osteonecrosis
- Malunited intercondylar fractures
- Malunited medial condyle fractures
Why is supracondylar fracture so common?
- Thin bone
- Olecranon impinges at the fossa with leverage and delivers point stress
- Lax soft tissue: amount for possible hyperextension
- Bone actively undergoing modeling at the site during 6 – 10 years of age
- A large number of actively growing physis in the vicinity account for increased vascularity in the region and resultant relative hyperemia
- Periosteal attachment to olecranon fossa (result in constant trans-condylar failure), the capsule is tight anteriorly and hinges tip against the fossa
Displacements in Cubital Varus
- Medial displacement
- Medial tilt
- Internal rotation
- Posterior displacement
- Posterior tilt
- Proximal migration
Complications following Supracondylar fracture
Early Complications
- Compartment syndrome
- Nerve Injury
- Vascular Injury
- Volkmann’s Ischemic Contracture
Late Complications
- Malunion
- Myositic ossificans
- Cubitus varus
- Cubitus valgus
- Tardy ulnar nerve palsy
- Chronic nerve entrapment in healed callus (METEV’S SIGH= Median nerve gets entrapped in fracture callus)
Puckering: Button holing of the fragment through anterior muscles particularly brachialis
Nerve Injury in supracondylar fracture according to displacement
| Posterior-medial type | Radial nerve |
| Postero-lateral type | Median nerve |
| Flexion type | Ulnar nerve |
Adequacy of reduction
Coronal plane: True AP view of the elbow is evaluated and compared with the normal side for Baumann’s angle and intact olecranon fossa
Change in 5° of Baumann’s angle -> 2° cubitus varus with malunion
Other is
- Homero-Ulnar-wrist alignment
- Metaphyseal diaphyseal angle
For rotational alignment
- Deformation in teardrop
- Anterior humeral line must transect capitullum
Gun – stock deformity
Associated deformities with cubitus varus
- Internal rotation
- Extension of distal fragment (Can get corrected with time)
- Shortening
- Medial shift
Difference between Supracondylar fracture and lateral condyle fracture
| Contents | Lateral condyle fracture | Supracondylar fractures |
|---|---|---|
| 3-point relationship | Disturbed | Maintained |
| Arm length | Normal | May be reduced |
| Thickening of supra-condylar ridges | Lateral only | Both sides |
| Instability | To varus stress | None |
| Fixed flexion deformity | Present | Absent |
| Movements | Restriction of rotation or flexion/extension is often seen | None ofter decrease ER in the shoulder due to bony deformity at the elbow |
| Hyperextension | Restricted | Seen |
| Complications | Delayed by months to years | Usually immediate and neurovascular |
| Long term | Arthrosis common | Very rare |
Treatment
French Osteotomy (Modified)
- Lateral Closing wedge osteotomy
| French Osteotomy | Modified French Osteotomy |
|---|---|
| Posterior longitudinal approach | Postero-lateral incision |
| Detach the lateral half of the tricep | The whole tricep detached |
| Ulnar nerve- exposed | Not explained |
| Medial periosteal hinge | Medial periosteal and bony hinge |
Rotational Correction:
- The proximal lateral screw is posterior to the coronal plane
- Distal -> Slightly anterior= Distal slightly anterior = Leads to external rotation of distal fragment after wires are tightened
Other Osteotomy Names:
- Dome osteotomy
- Oblique osteotomy with derotation
- Three-dimensional osteotomy
- Step cut osteotomy
- Medial opening wedge osteotomy with bone graft
Osteotomy is done at least 1 year following fracture (adequate duration for remodeling of bone and tissue equilibrium to gain)
No functional benefits after osteotomy only cosmetic
Complications:
- Stiffness
- Nerve Injury
- Under-correction
- Non-union
- Lazy- S- deformity
Pseudo cubitus varus deformity
Lateral condyle fracture: lateral spur formation, due to lateral elevation of periosteum by displaced fragment. No real change in angle but lateral prominence produces the appearance of cubitus varus
See also: Cubitus Valgus
See also: The Unstable Elbow
