The Importance of Plasma Sprayed Hydroxyapatite Coating on Titanium Plasma Spray in the Osseointegration of Total Ankle

Arthroplasty Implants

Robert Flavin, MD, Mark Steeves, MD, Alastair Younger, MD

Department of Foot & Ankle Surgery, St Paul’s Hospital, Vancouver, Canada

The Importance of Plasma Sprayed Hydroxyapatite Coating on Titanium

Plasma Spray in the Osseointegration of Total Ankle Arthroplasty Implants

Robert Flavin

My Disclosure is in the Final AOFAS Program Book, I have no potential

conflicts with this presentation

Introduction

Predicted 4-8.5 million North Americans will be afflicted by Ankle Arthritis by 2020

Ankle Arthritis is a major disability similar to Hip Arthritis

Ankle Arthrodesis remains the Gold Standard of care

Increasing patient preference for Total Ankle Arthroplasty

Introduction Many Implants with Many Differences

Implant Geometry, Surface Coating, 2 or 3 component designs (fixed or mobile)

Mode of Bonding: Ingrowth Osseointegration Principle Mode of Failure: Aseptic Loosening Our Instituition has used implants of two

ingrowth coating surface types CoCr Alloy with porous coated sintered titanium

beads without Hydroxyapatite (HA) CoCr alloy with porous coated surface with plasma

sprayed titanium with HA

Hypothesis The revision rates for Cobalt Chrome Alloy TAA

stemmed prostheses may be higher without Hydroxyapatite coating.

Therefore the objectives of this study were to analyze two separate total ankle arthroplasty designs with regards to; revision rates, loose components diagnosed both clinically and

radiologically by SPECT-CT, the description of implant ingrowth material on

explantation at the time of revision surgery symptomatic Impingement rates.

Materials & Methods Retrospective Analysis 2 Different Total Ankle Arthroplasty

Mobility (Dupuy International, Leeds, UK) Hintegra (Newdeal SA, Lyon, France)

33 Mobility TAA performed 37 Hintegra TAA performed Standardized Postoperative protocol Parameters collected from Medical Records Coronal and Sagittal tibial implant angles of

implantation measured on 6 week weight bearing Radiographs

Results TAA type Mobility TAA Hintegra TAA

Age (p=0.51)

63.9 Years (SD 9.9) 62.2 Years (SD 10.8)

Gender (p=0.58)

13 (43%) ♂ 17 (57%) ♀ 11 (31%) ♂ 24 (69%) ♀

Weight (p=0.617)

75.2 Kg (SD 15) 77 Kg (SD 14.6)

Rheumatoid Arthritis

10 (31.2%) 10 (28%)

Osteoarthritis 11 (34.4%) 14 (39%)

Posttraumatic Arthritis

11 (34.4%) 13 (33%)

(p=0.8081)

Results Revision & Impingement Rates

0123456789

10Ti

bial

Com

pone

nt

Tala

rC

ompo

nent

Tibi

alC

ompo

nent

Tala

rC

ompo

nent

Loosening on SPECT-CT

Requiring Revision ImpingementPain

No.

of p

atie

nts

HintegraMobility

Discussion The question of optimum implant geometry and surface

coating has not been debated in the literature to the best of our knowledge.

The literature shows clinical results of revision similar to our study but the studies are small case series or from the designer. All studies describe a “steep learning curve” phenomenon.

Geometrical analysis would show the anterior cortical window and the absence of HA as the potential attributing factors to failure to osseointegrate

References Glazebrook, M; Daniels, T; Younger, A, et al.: Comparison of health-related

quality of life between patients with end-stage ankle and hip arthrosis. J Bone Joint Surg Am. 90: 499-505. 2008 90/3/499

Hintermann, B; Valderrabano, V; Dereymaeker, G; Dick, W: The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Relat Res. 57-68. 2004

Pagenstert, GI; Barg, A; Leumann, AG, et al.: SPECT-CT imaging in degenerative joint disease of the foot and ankle. J Bone Joint Surg Br. 91: 1191-1196. 2009

Rippstein, PF; Huber, M; Coetzee, JC; Naal, FD: Total ankle replacement with use of a new three-component implant. J Bone Joint Surg Am. 93: 1426-1435. 2011

Rothman, RH; Hozack, WJ; Ranawat, A; Moriarty, L: Hydroxyapatite-coated femoral stems. A matched-pair analysis of coated and uncoated implants. J Bone Joint Surg Am. 78: 319-324. 1996

Wood, PL; Karski, MT; Watmough, P: Total ankle replacement: the results of 100 mobility total ankle replacements. J Bone Joint Surg Br. 92: 958-962. 2010