Ankle Arthroplasty: Can the Ankle Joint be Replaced ? Arash Aminian MD

Anatomy Biomechanics History Current Designs Indications Results Cases Overview Anatomy Biomechanics History Current Designs Indications Results Cases

Anatomy Talar Bony Anatomy 60% cartilage Blood supply Deltoid Artery of the sinus tarsi Artery of the tarsal canal

Anatomy Distal Tibial Anatomy

Anatomy: Stability Ankle ligaments Articular geometry Stormont et al AJSM 1985 13: 295. Ankle ligament sectioning study: Articular surface 30% rotational stability

Lateral Ankle Ligaments Anatomy: Ligaments Lateral Ankle Ligaments

Anatomy: Ligaments Deltoid (abduction/ER) Syndesmosis Anterior and Posterior Tibia-Fibula Interosseous Transverse T-F

Anatomy: Motion Multi-axial Motion DF EV Foot, IR Tibia PF IN Foot, ER Tibia Normal Motion DF 13-33 PF 23-56 Walking DF/PF 10/10-15 degrees

Biomechanics: Bone Support Subchondral bone of distal tibia modulous of elasticity 300-450 MPa Removal of: Subchondral bone lower compressive resistance by 30-50% 1 cm of bone by 70-90%

Biomechanics Vertical load 5.2 x BW during normal gait GR forces 3D Compressive Shear Torsional Micromotion (0.15 mm) prevents ingrowth CORR 1977 127:189-196.

History: Questions Restore Anatomy Which Surfaces to replace Fixation Poly size (4-6mm Hip, 6-8mm Knee, Ankle?)

History: Classification Fixation: Cemented, Uncemented Number of components: 2/3 Constraint: Constrained/Semi/Non Congruity/Conformity Component shape: Anatomic/Non-anatomic Bearing: Fixed/Mobile

History: 1970s First Generation Poorly designed instruments: mal-position Soft tissue balancing not addressed Bone cement for fixation Excessive bone removal Non-anatomically shaped implants Soft tissue envelope

History: 30 year Follow-up

Ankle Arthritis: Comparison of Health-Related Quality of Life Between Patients with End-Stage Ankle and Hip Arthrosis. Glazebrook et al. J Bone Joint Surg Am.2008; 90: 499-505. SF 36 scores cohort 136 ankle arthrosis/130 hip arthrosis Ankle arthrosis: worse mental component summary, role-physical score, general health score

Why Total Ankles: Ankle Fusion Nonunion rate 5-10% Gait: Difficulty with climbing stairs, walking on uneven grounds (Decreases DF 50%/ PF 70%) Adjacent joint arthritis: 23 year F/U 95% hindfoot arthrosis (JBJS B 85:994) 12-44 year F/U 91% subtalar; 57% TN arthrosis (JBJS A Caster et al 83: 219)

History: Second Generation Constraint: Resistance of the implant to degrees of freedom (shear stresses). Decreasing constraint minimizes shear stress forces at the bone-implant interface Congruity/Conformity: Radii of curvatures of the implant and poly-wear

Current Designs Agility (1984) Hintegra TNK Inbone (2005) STAR (2009) Salto-Tolaris (1997/2006) Buechel-Pappas

Ideal Design Small bone resection Anatomic (physiologic motion/balance ligaments) Unconstrained Porous surface (ingrowth within 3D spaces) with HA (early fixation) Large prosthesis (prevent subsidence) Motion DF/PF 10/20 degrees Poly 8 mm (increase durability) Poly conforming (decrease contact stresses: prevent loosening)

Indications and Considerations: Age Primary/Secondary Arthritis Deformity Good bone stock Normal neuro-vascular exam Motion Ankle Stability Low physical demand

Relative Contra-Indications: AVN Severe osteoperosis/penia IDDM Demanding work/sport activities Weight? Previous Infection?

Absolute Contra-Indications Deformity greater than 10 degrees Ligamentous Instability (lateral/medial) Poor soft-tissue envelope Neurovascular compromise Acute infection Joint hypermobility

Salto-Tolaris TAA FDA Approval 2008 2 component design Instrumentation Resection level Uncemented Anatomic

Results: Literature Review Intermediate and Long-Term Outcomes of Total Ankle Arthroplasty and Ankle Arthrodesis. A systematic review of the Literature. Haddad et al. J Bone Joint Surg Am.2007; 89: 1899-1905 TAA: 5 year survival 78% 10 year survival 77% Revision rate of 7%: Loosening or subsidence

Results: How successful are TAA Residual pain is common (27-60%) Superficial wound complications (0-14.7%) Deep wound complications (0-4.6%) Overall failure rate 10% at 5 years Gougoulias et al. CORR 2010 Jan:468(1): 199-208

Results: Survivorship 7-11 years for Salto TAA 85 patients (87 TAA): mean follow-up 8.9 years (6.8-11 years) Survival rate 65% with any reoperation, 85% with revision as an end point Causes of reoperation: Bone cysts (11) Fracture of the polyethylene (5) Pain (3) Bonnon M et al. CORR 2010 Jul 1

Complications: Evidence Based Classification of Complications in Total Ankle Arthroplasty Glazebrook et al Foot and Ankle Int 2009 Oct30(10): 945-9. Deep infection Aseptic loosening Implant failure Subsidence Fractures (intra-op/post-operative) Wound healing problems

TAA vs Ankle Fusion ? Preference-based Quality of Life of End-stage Ankle arthritis with Arthroplasty or Arthrodesis Slobogean et al. Foot and Ankle Int 2010 July 31(7): 563-6. Prospective study 107 patients with TAA /Arthrodesis: At one year follow-up SF-36 score TAA (0.73), Arthrodesis (0.73)

Outcome Measures 82 patients, average follow-up 60 months JBJS Am. 2012 Jan 4;94(1):43-8. Intermediate to long-term outcomes of the STAR Total Ankle Replacement: the patient perspective. 82 patients, average follow-up 60 months The most compelling finding of the present study involved the marked improvement in terms of the self-reported measures of impairments, quality of life, pain, and function.

Acta Orthop. 2011 Dec;82(6):655-9. 10-year survival of total ankle arthroplasties: a report on 780 cases from the Swedish Ankle Register. Of the 780 prostheses implanted since 1993, 168 (22%) had been revised by June 15, 2010. The overall survival rate fell from 0.81 (95% CI: 0.79-0.83) at 5 years to 0.69 (95% CI: 0.67-0.71) at 10 years. . Outcome Measures

Outcome Measures Foot Ankle Int. 2011 Aug;32(8):740-5. Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries. These were STAR Ankle, Büchel-Pappas, Hintegra, Mobility, Agility, and Ramses Total Ankle Arthroplasty. The revision rate was used as the main outcome parameter. Irrespective of the implant, the average revision rate to be expected according to the registry data available is 21.8% after 5 years, and 43.5% after 10 years.

74 year old female with long standing ankle pain Salto prosthesis 74 year old female with long standing ankle pain

Case 1 Year Follow-Up

Case 3 Year Follow-Up

Case: 3 Year Follow-up

Case: 3 Year Follow-up

Inbone prosthesis

Inbone prosthesis

STAR

STAR

Don’t Underestimate a Good ankle Fusion