Shoulder replacement procedure

Shoulder replacement, although done much less frequently than hip and knee replacement, is the third most prevalent joint replacement procedure worldwide. Current shoulder replacement systems rely on ultra-high molecular weight polyetiiylene (UHMWPE) components for motion and load bearing. Because of this critical role, the performance of UHMWPE components can determine the overall performance of the replacement system. 

The number of shoulder arthroplasty procedures done yearly has grown from an estimated 5000 per year in the United States between 1990 and 1992 (Wirth and Rockwood, Jr. 1996) to around 15,000 per year between 2002 and 2003 (Jackson 2003). Of these, a substantial portion are hemiarthroplasties. The prevalence of hemiarthroplasties as a percentage of the total number of replacements ranges from 14% (Edwards et al. 2002) in a multicenter study of OA, to 65% in a study of fracture repair (Boileau et al. 2001), to 87% in the Swedish shoulder arthroplasty register started in 1999 (Rahme, Jacobsen, and Salomonsson 2(X)1). Dr. Charles Neer, II, the pioneer of tiie procedure, estimates that overall, aroimd 20% of shoulder replacements are hemiarthroplasties (2003). 

The modern era of shoulder replacement was ushered in by Dr. Charles Neer, II. In 1953, in response to the relatively poor results of humeral head resection for patients with proximal humeral fractures. Dr. Neer implanted a vital-hum humeral component of his own design in a hemiarthroplasty procedure (Figure 9.4). In 1955, he reported on his first series of 12 pahents treated in this way. 

In spite of these issues, shoulder replacement with UHMWPE remains a successful procedure bringing lasting pain relief and restoration of function to tens of thousands of patients worldwide every year. 

Following the same procedure, the kinetic constants have been determined for very different electrochemical conditions. When n-WSe2 electrodes are compared in contact with different redox systems it is, for example, found9 that no PMC peak is measured in the presence of 0.1 M KI, but a clear peak occurs in presence of 0.1 M K4[Fe(CN)6], which is known to be a less efficient electron donor for this electrode in liquid junction solar cells. When K4[Fe(CN)6] is replaced by K3[Fe(CN)6], its oxidized form, a large shoulder is found, indicating that minority carriers cannot react efficiently at the semiconductor/electrolyte junction (Fig. 31). 

Eight procedures were dental, and 26 were orthopedic (17 of the latter were classified as major). Seventeen procedures were performed using continuous infusion (Table 3.8). Major procedures included total joint replacements total prostheses and endoprostheses and arthrodeses of the hip, knee, ankle, or shoulder. 

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