Hallux Valgus Flashcards
What is hallux valgus
A deformity of the first MTPJ
Colloqually called a bunion.
Epidemiology
One of the most common foot problems in adults
Prevalence of around 35% in those aged 65 or more
More common in women
During the gait cycle the digits should remain parallel to the long axis of the foot.
What makes this possible?
A balance of static stabilisers (bones and ligaments) and dynamic stabilisers (muscles and tendons).
Why is the 1st MTPJ most susceptible to valgus angulation?
It is unstable as it heavily relies on the stabilising structures of the foot.
This means that if a static or a dynamic stabiliser becomes disrupted the 1st MPTJ is most susceptible to deformity.
What happens to the big toe when the intrinsic stabilisers loses their control?
The extrinsic tendons become a deforming force leading to medial drift of the metatarsal head.
Risk factors
Female
Connective tissue disorder
Hypermobility syndromes
Flat foot
High heels
Narrow-fitting footwear
Clinical features
Painful medial prominence aggravated by walking, weight-bearing activities or wearing narrow toed shoes.
Examination findings
Medial deviation of 1st MTPJ + lateral deviation +/- rotation of the hallux with associated joint subluxation.
Inflammation and skin breakdown can be present
The foot should be assessed in both a non-weightbearing position and a weightbearing position.
Assess active and passive range of motion + crepitus to check for cartilage breakdown.
There might be contracture of extensor hallucis longus in longstanding joint subluxation and there might also be excessive keratosis on the foot.
Dx
Gout
SA
Hallux rigidus
OA
RA
Ix
Main investigation is X-ray and often useful to assess the degree of lateral deviation and signs of joint subuxation as well.
What confirms a diagnosis of hallux valgus?
Lateral deviation is measured as the angle between the first metatarsal and the first proximal phalanx.
Any angle greater than 15 degrees confirms diagnosis.
Severity of hallux valgus
Mild = 15-20 degrees
Moderate = 21-39 degrees
Severe = >40 degrees
Conservative management
Sufficient analgesia
Adjusting footwear to prevent deformity and further deterioration and preventing skin irritation.
If the patient has flat feet -> Orthosis
Physio for stretching and gait re-education
If a patient is severly impacted by the condition surgical interventions can be done.
There are a variety of procedures.
Chevron procedure
Scarf procedure
Lapidus procedure
Keller procedure
Explain Chevron
V-shaped osteotomy of distal first metatarsal.
This allows the first metatarsal to be shifted laterally back into normal alignment.
This is then fixed by pins and screws.
Used in mild deformities
Explain Scarf procedure
Longitudinal osteotomy within the shaft of first metatarsal.
Distal portion is moved laterally and fixed with two screws.
Used in moderate to severe disease
Explain Lapidus procedure
Base of first metatarsal and medial cuneiform are fused.
Often useful if there is an underlying tarsometatarsal joint hypermobility
Explain Keller procedure
Incision made over 1st MTPJ and joint capsule is opened to expose the joint.
Joint surfaces are removed for a space to be left that is stabilised by suturing of the surrounding tissues and subsequent scar tissue.
Common when there is severe MTPJ arthritis
Surgical complications
Wound infection
Delayed healing
Nerve injury
Osteomyelitis
Complications
Avascular necrosis
Non-union displacement
Reduced range of motion
Prognosis is variable
