To The Editor:
I read with great interest the article entitled “Copeland Surface
Replacement Arthroplasty of the Shoulder in Rheumatoid Arthritis”(2004;
86:512-518) by Levy et al. The long- term results of the Total Articular
Replacement Arthroplasty (TARA) corroborate the authors’ findings. The
TARA prosthesis with its characteristic curved stem was developed and
commonly used as a femoral head surfacing prosthesis starting in 1952.1,2
The humeral prosthesis had a shorter stem and was first used in 1957 by
the innovator Charles O. Townley of Port Huron, MI.
Since neither polyethylene nor polymethylmethacrylate was readily
available the prosthesis was used as a press fit hemiarthroplasty.
Starting in 1960 polyurethane was occasionally used to resurface the
glenoid and if the humeral fixation was in doubt polyurethane was used as
cement. More than 100 humeral TARA prostheses were implanted with a
follow-up interval as long as 33 years.
When a hemiarthroplasty was performed the glenoid was prepared, just
as the authors report for the Copeland prosthesis, by drilling to
encourage fibrous tissue in growth. The implant, therefore, functions as
an articular barrier assisting the formation of a self lubricating, soft,
mobile, pseudobiological fibrous joint. In the cases where polyurethane
was used it fragmented and ultimately disappeared radiographically. The
joint then functioned as a hemiarthroplasty. There was neither apparent adverse
reaction to polyurethane debris in patients nor were adverse changes found at necropsy in dogs.
Many of the patients also had hip arthritis and received a TARA hip
prosthesis. The size of the humeral and femoral surfacing prosthesis was
the same. A ceramic resurfacing prosthesis became available in 1995. Like
resurfacing operations for the hip, the technique of resurfacing
arthroplasty of the shoulder is demanding and critical to the long-term
success of the procedure.
James W. Pritchett, MD
1101 Madison #400
Seattle, WA 98104
JimP@PacMed.org
206 505 1043
1. Freeman M: Total surface hip arthroplasty. Clin Orthop 134:2-4,
1978.
2. Townley CO: Hemi and total articular replacement arthroplasty of
the hip with a
fixed femoral cup. Orthop Clin North Amer 13:869-894, 1982.
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