Cubitus Varus and Cubitus Valgus – Deformity, Evaluation and Treatment

Cubitus varus and cubitus valgus are coronal plane deformities of the elbow characterised by abnormal alteration of the physiological carrying angle. Although they are often described as primarily cosmetic deformities, clinically significant cases may produce instability, altered elbow mechanics, nerve dysfunction, secondary fractures and functional disability.

Cubitus varus refers to a decrease or reversal of the normal valgus carrying angle, producing a gunstock deformity. It is most commonly a sequela of malunited supracondylar humerus fracture in childhood.

Cubitus valgus refers to an excessive valgus carrying angle. It classically occurs following nonunion or malunion of a lateral condyle fracture of the humerus and may eventually cause tardy ulnar nerve palsy.

The carrying angle is the angle formed between the longitudinal axis of the arm and forearm when the elbow is fully extended and the forearm is supinated.

The normal elbow demonstrates physiological valgus. The exact value varies with age, sex, skeletal morphology and measurement technique.

• Children generally have a smaller carrying angle than adults.
• Females may demonstrate slightly greater physiological valgus on average.
• Comparison with the contralateral normal elbow is often more clinically useful than relying on a single numerical cutoff.

Always compare both elbows clinically and radiographically when evaluating a post-traumatic elbow deformity.

Cubitus varus is one of the most recognised late deformities following a paediatric supracondylar humerus fracture. The deformity is usually caused by malunion rather than growth arrest.

Although the visible abnormality is in the coronal plane, cubitus varus is frequently a three-dimensional deformity consisting of:

• Varus angulation.
• Internal rotation.
• Extension deformity.

The severity of each component varies between patients.

The commonest cause is malunion of a displaced supracondylar humerus fracture sustained during childhood.

• Inadequate reduction of supracondylar humerus fracture.
• Loss of reduction during conservative or operative treatment.
• Medial column collapse.
• Unrecognised rotational malalignment.
• Rarely, asymmetric physeal disturbance.
• Less commonly, malunion after distal humeral fractures from other causes.

In most cases, cubitus varus results from the distal humeral fragment healing in varus, extension and internal rotation.

Because most distal humeral growth occurs relatively slowly compared with other paediatric physes, substantial angular remodelling cannot be reliably expected, especially in the coronal plane.

Cubitus varus after supracondylar fracture is predominantly a malunion problem, not a growth-arrest problem.

Corrective surgery should therefore not focus solely on the visible coronal angulation when a significant rotational or sagittal component is present.

• Visible gunstock deformity when the elbow is extended.
• Reduced or reversed carrying angle.
• Often preserved elbow flexion-extension.
• Possible hyperextension.
• Internal rotation deformity may be clinically demonstrable.
• Cosmetic concern is a frequent presenting complaint.
• Late posterolateral rotatory instability may occur in some patients.
• Occasional pain or functional limitation.

Cubitus varus was historically regarded mainly as a cosmetic problem. Long-term studies have demonstrated that abnormal elbow mechanics may predispose to several functional problems.

• Posterolateral rotatory instability.
• Lateral collateral ligament complex dysfunction.
• Tardy ulnar neuropathy in selected cases.
• Snapping triceps.
• Altered triceps mechanics.
• Increased susceptibility to lateral condyle fractures in children.
• Cosmetic dissatisfaction.

Evaluation should determine both the severity and the three-dimensional character of the deformity.

Clinical Examination

• Inspect both elbows in full extension.
• Measure and compare carrying angles.
• Assess elbow flexion-extension range.
• Assess forearm rotation.
• Look for hyperextension.
• Evaluate axial rotation of the arm.
• Assess elbow stability.
• Perform neurovascular examination.
• Assess the patient's cosmetic and functional concerns.

Standard anteroposterior and lateral radiographs of the elbow are usually obtained. Comparative radiographs of the opposite elbow may be helpful when planning correction.

Measurements may include:

• Humerus-elbow-wrist angle.
• Carrying angle.
• Baumann angle in paediatric deformity assessment.
• Anterior humeral line and sagittal alignment.
• Rotational assessment using clinical examination and, selectively, advanced imaging.

CT with three-dimensional reconstruction may be useful in severe multiplanar deformities or complex revision surgery but is not mandatory in every case.

Mild asymptomatic deformity may be observed. Operative correction is considered when deformity is clinically significant.

• Significant cosmetic deformity.
• Progressive functional limitation.
• Elbow instability.
• Neurological symptoms.
• Symptomatic snapping triceps.
• Marked multiplanar deformity.

The decision to operate should incorporate patient age, deformity magnitude, symptoms and expectations rather than radiographic angle alone.

Corrective osteotomy is usually performed in the distal humeral metaphysis, close to the centre of deformity.

The objectives are to:

• Restore physiological valgus.
• Correct extension or flexion abnormality where necessary.
• Correct significant rotational deformity.
• Preserve limb length where possible.
• Obtain stable fixation permitting union.
• Avoid excessive prominence or lateral condylar translation.

Lateral closing-wedge osteotomy is one of the classic and most widely used procedures for cubitus varus correction.

A laterally based wedge of bone is removed from the distal humerus and the osteotomy is closed, converting the varus alignment into physiological valgus.

Advantages

• Relatively simple technique.
• Broad osteotomy surfaces.
• Predictable coronal correction.
• Well-established procedure.

Potential Problems

• Lateral condylar prominence.
• Loss of correction.
• Residual rotational deformity.
• Limb shortening.
• Cosmetically unacceptable lateral translation.

A technically correct coronal correction may still produce a poor cosmetic result if lateral condylar prominence is not considered.

Dome osteotomy uses a curved osteotomy allowing the distal fragment to rotate around the centre of the curve.

Advantages

• Allows angular correction without removing a large wedge of bone.
• Minimal shortening.
• Large bony contact surface.
• May reduce lateral condylar prominence.

The technique requires accurate planning and may be technically more demanding than a simple closing-wedge osteotomy.

Step-cut osteotomy is designed to provide inherent rotational stability through interlocking osteotomy surfaces.

Potential advantages include:

• Large area of bony contact.
• Improved rotational control.
• Potentially stable fixation.
• Correction of more than one deformity component when appropriately planned.

In patients with substantial varus, internal rotation and extension deformity, a simple two-dimensional wedge correction may leave clinically relevant residual deformity.

Three-dimensional osteotomy planning aims to correct all major components simultaneously. Computer-assisted planning, patient-specific cutting guides and three-dimensional printed models can be useful in complex deformities.

Fixation depends on patient age, osteotomy design, bone quality and surgeon preference.

• Crossed or divergent K-wires in younger children.
• Plate-and-screw fixation in older children and adults.
• Locking plates in selected situations requiring greater angular stability.

Stable fixation reduces the risk of loss of correction and facilitates controlled mobilisation when appropriate.

• Loss of correction.
• Overcorrection into excessive valgus.
• Residual varus.
• Lateral condylar prominence.
• Nonunion or delayed union.
• Hardware prominence.
• Elbow stiffness.
• Nerve injury.
• Infection.
• Residual rotational deformity.

Cubitus valgus is an excessive lateral angulation of the forearm relative to the arm when the elbow is extended and the forearm supinated.

The classic acquired cause in childhood is a neglected or inadequately treated lateral condyle fracture of the humerus. Lateral condylar nonunion, growth disturbance and progressive deformity can alter the carrying angle and stretch the ulnar nerve over time.

• Nonunion of lateral condyle fracture of the humerus.
• Malunion of lateral condyle fracture.
• Physeal disturbance involving the distal humerus.
• Post-traumatic lateral column growth disturbance.
• Congenital or developmental deformity in selected disorders.
• Malunion following distal humeral fracture.

A displaced lateral condyle fracture may fail to unite if untreated or inadequately stabilised. Progressive deformity may develop because of abnormal distal humeral growth and altered elbow mechanics.

The resulting excessive valgus places the ulnar nerve under chronic traction as it passes behind the medial epicondyle.

Years after the original childhood fracture, the patient may present with symptoms of ulnar neuropathy. This delayed neurological complication is classically known as tardy ulnar nerve palsy.

• Excessive carrying angle.
• Visible lateral deviation of the forearm.
• History of childhood lateral condyle injury may be present.
• Possible elbow instability.
• Pain or fatigue around the elbow.
• Ulnar nerve paraesthesia.
• Numbness of the little finger and ulnar half of ring finger.
• Intrinsic hand weakness in advanced neuropathy.

Tardy ulnar nerve palsy is a delayed ulnar neuropathy occurring years after an elbow injury or deformity. Cubitus valgus is one of the classic causes.

Progressive valgus causes repeated traction and irritation of the ulnar nerve around the medial epicondyle.

Symptoms

• Paresthesia in the ulnar digits.
• Reduced grip strength.
• Intrinsic muscle weakness.
• Difficulty with fine motor activities.
• Clawing in advanced disease.

Examination

• Sensory examination in the ulnar nerve distribution.
• Interosseous muscle power.
• Froment sign.
• Wartenberg sign.
• Tinel sign over the cubital tunnel.
• Assessment for intrinsic muscle wasting.

• Standing or standard AP elbow radiograph with full extension where feasible.
• Lateral elbow radiograph.
• Comparison with the opposite side.
• Assessment for lateral condyle nonunion or malunion.
• Evaluation of the joint surface and degenerative changes.
• Nerve conduction studies when significant ulnar neuropathy is suspected.
• CT may assist in complex nonunion or deformity planning.

Treatment depends on the cause of deformity, patient age, symptoms, neurological involvement and condition of the lateral condyle.

Mild asymptomatic deformity may require observation. Surgery is considered when there is significant deformity, progressive symptoms, instability or ulnar neuropathy.

Surgical treatment may involve:

• Corrective distal humeral osteotomy.
• Management of lateral condyle nonunion where appropriate.
• Ulnar nerve decompression or anterior transposition in selected patients.
• Combined deformity correction and nerve procedure where required.

In a symptomatic patient with substantial valgus deformity, a distal humeral corrective osteotomy may be performed to restore a more physiological carrying angle.

Depending on the deformity, techniques include:

• Medial closing-wedge osteotomy.
• Opening-wedge osteotomy.
• Dome osteotomy.
• Multiplanar corrective osteotomy.

The chosen technique should correct the deformity while maintaining stability and avoiding neurovascular injury.

Management of longstanding lateral condyle nonunion is controversial and must be individualised. Important considerations include:

• Age of the patient.
• Duration of nonunion.
• Size and viability of the fragment.
• Articular congruity.
• Amount of displacement.
• Presence of valgus deformity.
• Ulnar nerve symptoms.
• Secondary degenerative changes.

In selected younger patients, fixation of a viable nonunion with bone grafting may be considered. In longstanding adult deformity, treatment may focus primarily on deformity correction and ulnar nerve management rather than attempting anatomical restoration of a chronically displaced fragment.

Patients with symptomatic tardy ulnar neuropathy require careful neurological assessment.

Surgical options may include:

• In-situ decompression in selected compression neuropathies.
• Anterior subcutaneous transposition.
• Anterior intramuscular or submuscular transposition in selected cases.

In cubitus valgus, anterior transposition may reduce the chronic traction placed on the nerve by moving it anterior to the axis of elbow motion.

• Cubitus varus is the classic late deformity after malunited supracondylar humerus fracture.
• Cubitus varus is usually caused by malunion rather than physeal arrest.
• Cubitus varus is often a three-dimensional deformity involving varus, internal rotation and extension.
• The classic cosmetic appearance of cubitus varus is called a gunstock deformity.
• Cubitus varus may predispose to posterolateral rotatory instability and is therefore not always purely cosmetic.
• Lateral closing-wedge osteotomy is a classic treatment for cubitus varus.
• Lateral condylar prominence is an important cosmetic complication after closing-wedge correction.
• Dome osteotomy can reduce shortening and lateral translation compared with a simple closing wedge.
• Cubitus valgus classically follows nonunion of a lateral condyle fracture.
• The classic neurological complication of cubitus valgus is tardy ulnar nerve palsy.
• Tardy ulnar neuropathy develops due to chronic stretching and irritation of the ulnar nerve around the medial epicondyle.
• Symptomatic cubitus valgus may require corrective osteotomy with or without an ulnar nerve procedure.
• Always compare deformity with the opposite elbow before planning correction.
• Surgical planning should consider coronal, sagittal and rotational deformity rather than the carrying angle alone.

Cubitus varus and valgus should be approached as post-traumatic elbow deformities rather than purely abnormalities of the carrying angle.

1. Identify the direction of deformity: varus or excessive valgus.
2. Determine the cause: supracondylar malunion for varus and lateral condyle pathology for valgus are the classic associations.
3. Assess the entire deformity: coronal, sagittal and rotational components.
4. Look for complications: instability in cubitus varus and ulnar neuropathy in cubitus valgus.
5. Observe mild asymptomatic deformity: surgery is not required purely because an abnormal radiographic angle exists.
6. Plan corrective osteotomy carefully: restore alignment while minimising shortening, prominence and neurovascular complications.
7. Address associated pathology: especially lateral condyle nonunion and ulnar nerve dysfunction in cubitus valgus.

Cubitus varus: think supracondylar malunion and three-dimensional deformity. Cubitus valgus: think lateral condyle nonunion and tardy ulnar nerve palsy.