Degenerative Ankle: Fusion vs.
Arthroplasty
|
|
|
A)
Post-traumatic arthritis B) Following tibiotalar arthrodesis (fusion) |
Definition:
o Loss of tibiotalar joint
space, destruction or degeneration of cartilage
Etiology of Arthritis:
o
Posttraumatic
o
Chronic degenerative, idiopathic
(osteoarthritis)
o
Inflammatory (rheumatoid)
o
Septic (infection)
o
Metabolic (gout)
Symptoms:
o Pain with weight-bearing
o Progressive and significant
decrease in activity due to pain
Physical Exam:
o Decreased ankle dorsiflexion
and plantarflexion (eversion and inversion are subtalar joint motions)
Radiographic findings:
o Joint space narrowing
o Subchondral sclerosis
o Osteophytes (spurs)
o Subchondral cysts
Surgical Treatment Options:
o Ankle Arthrodesis (fusion)
|
|
|
|
Post-op
radiographs of ankle arthrodesis with distal fibula as biological plate |
Motion
following ankle (tibiotalar) fusion:
Radiographs above demonstrate that dorsiflexion (DF) and plantarflexion
(PF) motion in the subtalar and transverse tarsal joints is preserved
and frequently increases to compensate for the lost tibiotalar motion |
- Ankle
Arthroplasty (replacement)
Principles of
arthrodesis:
- Appose
broad, cancellous, bony surfaces
- Stabilize
fusion with rigid fixation (eg screws)
- Correct
alignment of foot
Goals of
arthrodesis:
- Eliminate
joint pain
- Create
stable, plantigrade foot
Ankle Arthroplasty:
- Replaces
ankle joint with metal prosthesis
- Two main
designs
- Two-component
fixed-bearing design
- Three-component
mobile-bearing design
- Ankle
arthroplasty not widely perfomed due to first generation failures in the
1970’s
- Ankle
soft tissues are thin, easily compromised by previous trauma, surgery,
disease, or steroid use
- Delayed
wound healing in up to 40% of patients
- Deep
infection rates between 3-5%
- New generation
prostheses claim improved implant survival
- Not yet
FDA approved
|
|
|
