Knee arthroplasty/replacement

UHMWPE was introduced for knee arthroplasty at the same place, and at around the same time, as it was introduced for hip replacement. As we have seen in Chapter 4, John Charnley introduced UHMWPE for hip arthroplasty... 

Examples of knee arthroplasty during the 1960s. (A) Walldius hinged knee replacement (B) the Shiers, Walldius, and Guepar hinged knee replacements, superimposed over the anatomy of the knee (reprinted with permission from Walker RS. 1977. Human joints and their artificial replacements. Springfield, IL CC Thomas Publisher) (C) Macintosh tibial plateau and (D) McKeever tibial plateau. 

Ranawat C.S., H.A. Rose, and W.J. Bryan. 1984. Replacement of the patello-femoral joint with the total condylar knee arthroplasty. Int Orthop 8 61-65. 

Although knee arthroplasty enjoys a remarkable clinical track record, problems with wear and fatigue damage of UHMWPE continue to limit the longevity of both unicondylar and bicondylar knee replacement components. Unlike in the hip, where radiographic techniques have been developed to quantify in vivo wear rates, there currently exist no standard and widely accepted techniques for tracking the clinical performance of UHMWPE in patients with knee replacement. Thus, today the most effective way to evaluate the in vivo performance of UHMWPE continues to be the analysis of retrieved components from revision surgery or from autopsy donations. 

This chapter contains four main sections covering TKA and, where applicable, UKA. The first section reviews the biomechanical considerations of knee arthroplasty that distinguish it from hip replacement. The second section describes the survivorship of TKA and UKA, and outlines measures of clinical performance for UHMWPE in knee arthroplasty. The third section is devoted to wear and osteolysis in TKA. In the final section of this chapter, alternatives to metal-on-conventional UHMWPE articulation for knee arttiroplasty are described. 

Despite its successful track record, wear and damage of the UHMWPE insert compromises the longevity of knee arthroplasty. Osteolysis, a rare occurrence with all-UHMWPE tibial components, has been documented with increasing frequency in modular knee replacements. Clearly, improved wear behavior of the UHMWPE insert would be advantageous from the perspective of reducing the risk of osteolysis and aseptic loosening. 

A 75-year-old woman xmderwent elective total knee arthroplasty xmder general anaesthesia in combination with peripheral nerve blockade. Due to postoperative pain she received nefopam (80mg/24h). One day later she complained of sharp ocular pain and fuzzy vision. As first suspicion was keratitis, she received eye drops. However, a few hours later, she also complained of headache, which was recognized as migraine with ocular aura. At the same time, nefopam was stopped and replaced by tramadol 100 mg. Both tiie head ache and eye pain improved, but did not completely resolve and were discovered six days after surgery to be due to acute angle closure glaucoma [50 ]. 

One of the greatest concerns about the use of PE in joint replacement bearing surfaces is the wear of the material and the effect the wear debris has on the surrounding tissues. For many years, it has been demonstrated that this wear debris leads to osteolysis and loosening of the prosthetic components [21, 25]. Wear of the polyethylene or loosening of the implants, which may be related to wear debris, remains a common reason for revision surgery after total hip [26, 27] or total knee arthroplasty [28]. 

UHMWPE has been used in knee replacements since the late 1960s, when Frank Gunston developed a cemented implant design at Wrightington Hospital [5, 6]. This early knee replacement resurfaced the individual condyles of the femur and the tibia. Total knee arthroplasty (TKA), which replaces the articulation between the femur and tibia, as well as between the femur and the patella, was developed in the 1970s, primarily at surgical centers in North America. The basic anatomical landmarks and implant features of a typical total knee replacement are illustrated in Figure 7.1. 

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