Ankle Arthritis - Foot & Ankle

Introduction

Defined as osteoarthritis of the tibiotalar joint
Epidemiology
- less common than OA of knee and hip
Pathophysiology
- causes include
  - post-traumatic arthritis
    - most common etiology, accounting for greater than 2/3 of all ankle arthritis
  - primary osteoarthritis
    - accounts for less than 10% of all ankle arthritis
  - other etiologies include rheumatoid arthritis, osteonecrosis, neuropathic, septic, gout, and hemophiliac
- pathoanatomy
  - nonanatomic fracture healing alters the joint contact forces of the ankle and changes the load bearing mechanics of the ankle joint
  - loss of cartilage on the talar body and tibial plafond results in joint space narrowing, subchondral sclerosis and eburnation

Anatomy

Osteology
- a ginglymus joint that includes the tibia, talus, and fibula
- talar dome is biconcave with a central sulcus
Range of motion
- ankle dorsiflexion: 20 degrees
- ankle plantar flexion: 50 degrees

Classification

Takakura Classification
Stage I	Early sclerosis and osteophyte formation, no joint space narrowing
Stage II	Narrowing of medial joint space (no subchondral bone contact)
Stage IIIA	Obliteration of joint space at the medial malleolus, with subchondral bone contact
Stage IIIB	Obliteration of joint space over roof of talar dome, with subchondral bone contact
Stage IV	Obliteration of joint space with complete bone contact

Presentation

Symptoms
- pain with weight bearing
- loss of motion
Physical exam
- joint effusion
- pain with ROM testing, loss of ROM compared to the contralateral side
- angular deformity may be present depending on the history of trauma

Imaging

Radiographs
- recommended views
  - weight bearing AP, lateral, and obliques
- radiographic findings include
  - loss of joint space
  - subchondral sclerosis and cysts
  - eburnation
  - possible angular deformity

Treatment

Nonoperative
- activity modification, bracing to immobilize the ankle, and NSAIDS
  - indications
    - indicated as first line of treatment in mild disease
    - single rocker sole shoe modification can improve gait and pain symptoms
    - Arizona brace (gauntlet ankle brace)
Operative
- surgical management
  - indications
    - indicated upon failure of conservative treatment in a patient with radiographic evidence of ankle arthritis

Surgical Techniques

Ankle debridement with anterior tibial/dorsal talar exostectomy
- indications
  - mild disease with pain during push off
Distraction arthroplasty
- controversial
- ideal candidate younger than 45 yrs with post-traumatic arthritis
- indications
  - well-preserved ankle ROM
  - moderate to severe arthritis
  - congruent tibiotalar surface
  - also for partial AVN talus
Supramalleolar osteotomy
- indications
  - near-normal ROM
  - minimal talar-tilt or varus heel alignment
  - medially focused ankle arthritis
    - stage 2 or 3a according to the Takakura-Tanaka classification for varus-type osteoarthritis
Arthrodesis
- indications
  - posttraumatic or inflammatory arthritis, malalignment (with osteotomy)
- outcomes
  - reliable relief of pain and return to activities of daily living
- complications
  - long term studies demonstrate subtalar arthrosis
    - 50% of patients demonstrated subtalar arthrosis 10 years following ankle arthrodesis in one study
  - Risk factors for nonunion include smoking, adjacent joint fusion, history of failed previous arthrodesis, and avascular necrosis
  - revision arthrodesis union rates are 85% or greater
Arthroplasty
- indications
  - patient selection is crucial
    - indications
      - posttraumatic or inflammatory arthritis, elderly patient
    - contraindications
      - uncorrectable deformity, severe osteoporosis, talus osteonecrosis, charcot joint, ankle instability, obesity, and young laborers increase the risk of failure and revision
- techniques
  - new generation arthroplasty minimizes bony resection, retains soft tissue stabilizers, and relies on anatomic balancing
- outcomes
  - recent 5-10 year outcome studies demonstrate up to 90% good to excellent clinical results, long-term studies are still pending on the newest generation of ankle arthroplasty
  - increased gait speed and stride length
- complications
  - syndesmosis nonunion
  - include wound infection, deep infection, and osteolysis