**1. Introduction**

458 Recent Advances in Arthroplasty

Trampuz, A.; Piper, K.E.; Jacobson, M.J.; Hanssen, A.D.; Unni, K.K.; Osmon, D.R.;

Tunney, M.M.; Patrick, S.; Gorman, S.P.; Nixon, J.R.; Anderson, N.; Davis, R.I.; Hanna, D. &

Tunney, M.M.; Patrick, S.; Curran, M.D.; Ramage, G.; Hanna, D.; Nixon, J.R.; Gorman, S.P.;

Virolainen, P.; Lähteenmäki, H.; Hiltunen, A.; Sipola, E.; Meurman, O. & Nelimarkka, O.

Williams, J.L.; Norman, P. & Stockley, I. (2004). The value of hip aspiration versus tissue

*Arthroplasty,* Vol. 19, No. 5, (August 2004), pp. 582-586, ISSN 0883-5403 Zimmerli, W.; Trampuz, A. & Ochsner, P.E. (2004). Prosthetic-joint infections. *New England Journal of Medicine,* Vol. 351, No. 16, (October 2004), pp. 1645-1654, ISSN 1533-4406

Vol. 80, No. 4, (July 1998), pp. 568-572, ISSN 0301-620X

1999), pp. 3281-3290, ISSN 0095-1137

4406

1457-4969

Mandrekar, J.N.; Cockerill, F.R.; Steckelberg, J.M.; Greenleaf, J.F. & Patel, R. (2007). Sonication of removed hip and knee prostheses for diagnosis of infection. *New England Journal of Medicine,* Vol. 357, No. 7, (August 2007), pp. 654-663, ISSN 1533-

Ramage, G. (1998). Improved detection of infection in hip replacements. A currently underestimated problem. *Journal of Bone and Joint Surgery. British Volume,*

Davis, R.I. & Anderson, N. (1999). Detection of prosthetic hip infection at revision arthroplasty by immunofluorescence microscopy and PCR amplification of the bacterial 16S rRNA gene. *Journal of Clinical Microbiology,* Vol. 37, No. 10, (October

(2002). The reliability of diagnosis of infection during revision arthroplasties. *Scandinavian Journal of Surgery,* Vol. 91, No. 2, (August 2002), pp. 178-181, ISSN

biopsy in diagnosing infection before exchange hip arthroplasty surgery. *Journal of* 

Prosthetic joints improve the quality of life, but they may fail, necessitating revision or resection arthroplasty. The numbers of primary total hip and total knee arthroplasties have been increasing over the past decade, with nearly 800,000 such procedures performed in the United States in 2006 (Fig.1A)[1],with numbers projected to rise to 572,000 by 2030 and are expected to undergo a continuing rise, especially in light of an aging population[2]. Procedures to replace the shoulder, elbow, wrist, ankle, temporomandibular, metacarpophalangeal and interphalangeal joints are less commonly performed. The growth in the number of prosthetic joint replacement procedures provides new opportunities for infections to take hold.

The classification of the arthroplasty associated infection may distinguishes two major types―septic arthritis and osteomyelitis, which both involve the inflammatory destruction of joint and bone. The incidence of septic arthritis is between 2 and 10 in 100,000 in the general populace but may be as high as 30–70 per 100,000 in rheumatoid arthritis sufferers or recipients of prosthetic joints [3-5] and is more common in children than adults, and in males rather than females [6]. Haematogenous osteomyelitis most frequently effects children and the elderly [7]. In children, the incidence is typically between 1 in 5000 and 1 in 10,000 [8]. It has been argued that the incidence of haematogenous osteomyelitis is decreasing with an annual fall in childhood cases of 0.185 per 100,000 people recorded in Glasgow, Scotland between 1970 and 1997 [8-10]. Conversely, osteomyelitis resulting from direct infection is reportedly on the increase[10,11]. Local spread of infection from contiguous tissue to bone or direct infection can occur at any age, with foreign body implants a substantial risk factor [7]. Infection, although uncommon, is the most serious complication, occurring in 0.8 to 1.9% of knee arthroplasties[12-14] and 0.3 to 1.7% of hip arthroplasties[14-16]. The frequency of infection is increasing as the number of primary arthroplasties increases (Fig. 1B)[17]. These
