11 – Adult foot deformities + static disorders of the foot

Basics of adult foot deformities

Most common foot conditions
- Forefoot
  - Hallux valgus
  - Hallux rigidus
  - Metatarsalgia
  - Morton neuroma
  - Tailors bunion
- Flatfoot
- Hindfoot
  - Ankle joint osteoarthritis
  - Subtalar joint osteoarthritis
  - Heel spur
  - Plantar fasciitis
  - Haglund’s heel
  - Achilles tendon problems

3. Flat foot (pes planovalgus)

Flat foot = pes planus = pes planovalgus
Flat foot occurs due to flattening of one or more of the arches of the foot
- Due to muscle insufficiency or failing capsules and ligaments
Flat foot can occur in children and in adults
The arches of the feet develop a while after birth – flatfoot in newborns is normal
Etiology
- Increased bodyweight
- Being forced to stand early as a baby (too early walking age)
- Standing all day at work
- Bad shoes
- Old age
Types of flat foot
- Pes transversoplanus – flat transverse arch
- Pes planus – flat longitudinal arch
Clinical features
- In children
  - Pain in muscles of the thigh and calf after activity
  - Due to the muscles actively working to correct the flatfoot
- In adults
  - Pain in the area of the flat arch during activity
  - In adults the muscles have given up trying to correct the flatfoot
- Heel valgus
- Pes transversoplanus -> wide forefoot
- When tip-toeing a non-fixed flatfoot will gain back the arch
Prevention
- Don’t let your child walk too early (before 1 year)
- Preventative muscle exercises
- Tickle baby feet
- Prevent obesity
Treatment
- Conservative
  - Heel wedge – corrects heel valgus
  - Arch support
    - Arch support is not treatment – they will cause do the job of the muscles, causing them to get weaker
    - Arch support can prevent pain but does not treat the underlying flatfoot
- Surgical: Calcaneo-stop procedure
  - A screw is drilled into the calcaneus
  - The screw causes discomfort to the patient -> this forces the patient to use their muscles to correct their foot
Complications:
- Pes planus fixatus (= fixed flatfoot)
  - Due to tarsal coalition (fusion of tarsal bones), which occurs secondary to untreated flatfoot or as a developmental malformation
  - When tip-toeing a fixed flatfoot will not gain back the arch
  - Tarsal coalitions can be resected surgically
- Hallux valgus
- Bunion
- Hammertoe
- Osteoarthritis

9. Hallux valgus, mallet finger, digitus V. varus, bunion

Etiology
- Genetics
- Shoe wear
- Anatomical variations
Pathology
- Valgus deformity of big toe
- Flexor tendons are dislocated laterally
- Extensor tendon slips down
Diagnosis
- X-ray
- Hallux valgus angle (HVA) > 15 degrees
  - Angle between the long axis of the first metatarsal and the long axis of the first phalanx
- Intermetatarsal angle (IMA) > 9 degrees
  - Angle between first and second metatarsal
- Distal metatarsal articular angle (DMAA) > 10 degrees
- Dislocation of sesamoid bone
Stages
- Light
  - HVA 15 – 30 degrees
  - IMA 9 – 13 degrees
- Moderate
  - HVA 30 – 40 degrees
  - IMA 13 – 20 degrees
- Severe
  - HVA > 40 degrees
  - IMA > 20 degrees
Treatment
- Conservative treatment
  - Not very effective
  - Involves using hallux valgus splints
- Surgical treatment
  - Preoperative
    - Antibiotic prophylaxis
    - 350 mmHg tourniquet to prevent bleeding
  - Operative techniques
    - Lateral release
      - The adductor tendon and lateral capsule are cut (released)
    - Distal chevron metatarsal osteotomy (DCMO)
      - A wedge-shaped part of the first metatarsal is slipped laterally and then fixed in the correct position
    - Scarf osteotomy
    - Lapidus operation
      - Involves osteodesis of medial cuneiform and first metatarsal bone
      - Used for severe deformities
- Postoperative management
  - RICE
  - LMWH
  - Lymph drainage
  - Special shoe wear which prevents weightbearing on the forefoot
    - Worn for 4 – 6 weeks
  - Later – orthopaedic insoles

Toe deformity with PIP flexion + DIP extension + neutral MTP
Most commonly affects 2nd and the other lesser toes
Etiology
- Poorly fitting shoes
- Polyneuropathy
- Rheumatoid arthritis
- Trauma
Treatment: remove head of proximal phalanx

Bunion is an exostosis on the side of the foot
Most commonly on the medial side, in connection with hallux valgus
Treatment: bunionectomy (removal of the exostosis)

Tailor’s bunion (= bunionette)
- = digitus V. varus (varus of the fifth digit)
- Prominence on lateral side of foot (fifth metatarsal joint)
- Treatment: Scarf-like osteotomy

Mallet finger occurs due to trauma to extensor digitorum tendon
Due to trauma of the finger in extended position, which causes sudden forced flexion
- Often occurs when trying to catch a ball, so it’s also called baseball finger
Often occurs in fingers 3, 4 and 5
Can cause fracture or subluxation
Treatment
- Conservative
  - Extension splinting of DIP joint
- Surgical
  - In severe cases

32. Sterile necrosis of the foot bones

Osteonecrosis, also called avascular necrosis, refers to ischaemic necrosis of bone caused by impaired blood supply. It may affect any part of the bone but most commonly the knee and femoral head. It's most common in children and adolescents.

See also osteonecrosis of the foot and osteonecrosis of the hip, both of which most commonly occur in children.

Etiology

In children
- Idiopathic
- Overuse
In adults
- Alcoholism
- Chronic steroid treatment
- Radiotherapy
- Trauma
- Sickle cell disease

Pathology

There is ischaemia of bone which leads to necrosis. In children the condition mostly resolves spontaneously, as the bone can still repair itself. In adults the condition is generally irreversible, as bone can no longer repair itself as well.

Osteonecrosis in children and adolescents

Osgood-Schlatter disease
- Avascular necrosis of the tibial tuberosity (the insertion of the quadriceps)
- Occurs in adolescents, male > female
- A characteristic lump forms on the tibia
- Related to overuse
Perthes disease
- Avascular necrosis of the femoral head
- Occurs in children, male > female
- Idiopathic
Kohler disease
- Avascular necrosis of the navicular bone of the foot
- Occurs in children, male > female
- Idiopathic
- Rare
- Presents with pain on dorsal and medial surface of foot
- It’s self-limiting, so conservative treatment with NSAIDs and immobilization is the only treatment
  - No role for surgery
Osteonecrosis of the 2nd metatarsal head (Freiberg disease)
- In adolescents (13 – 18)
- Girls > boys
- Presents with pain on forefoot
- Treatment
  - Conservative
    - NSAIDs
    - Immobilization
  - Surgery
    - Rarely needed (only in severe disease)
    - Osteotomy/arthrotomy
Sever disease
- Osteonecrosis of calcaneal apophysis (the tuberosity of the calcaneus), also called calcaneal apophysitis
- Often occurs in young athletes (8 – 12)
- Pain in the area of the calcaneal apophysis
- It’s self-limiting, so conservative treatment with NSAIDs and immobilization is the only treatment
  - A soft heel pad decreases the pressure on the calcaneus
  - No role for surgery

Osteonecrosis in adults

Avascular necrosis of the hip
- Osteonecrosis of the hip, also called femoral head necrosis, is the most common localisation of osteonecrosis. The femoral head is the most frequent area of osteonecrosis probably due to the intricate blood supply.
- Occurs in middle-aged, male > female
- A common indication for total hip replacement
- Etiology
  - Idiopathic (Perthes disease)
  - Trauma
    - Femoral head fracture
  - Chronic steroid
  - Alcoholism
  - Radiation
- Clinical features
  - Insidious onset of pain
  - Affects both hips most of the time
- Diagnosis: MRI
- Treatment
  - Conservative
    - Bisphosphonates
    - Exercise
  - Surgery
Ahlback disease
- Avascular necrosis of the medial femoral condyle
- Occurs in elderly, female > male

Clinical features

Pain
- Usually of insidious onset
- Exacerbated by use
Loss of function (in late stages)

Diagnosis and evaluation

Imaging

MRI is the main imaging modality in the evaluation of osteonecrosis.

Management

Treatment depends on localization, extent, and age. In children the treatment is generally conservative with RICE and NSAIDs. In adults the management may be conservative or surgical depending on the area and etiology.