**Author details**

tures, dislocation, infection or osteolysis. Also, the few patients suffering from "squeaking" hips have, in the majority of cases, had no need for revision surgery. These are, therefore, excellent results, but Lee *et al* (2010) [44] did suggest that these small risks should be a con‐ cern to surgeons and that patients should also be made aware of these before surgery. In ad‐ dition to this, they mentioned that longer-term follow-up is needed to assess the effects of

As these artificial hip joints have been found to perform well in the younger patient (45 to 55 years), some surgeons have chosen to replace the diseased joints of even younger patients

A case study was reported by Capello and Feinberg (2009) [88] where ceramic-on-ceramic joints were implanted in a 13 year-old child with bilateral end-stage arthritis of the hip. Seven and eight years post-operatively the patient had no pain, no limp, and was able to walk long distances. The radiographs showed no implant loosening, osteolysis or wear. This is a very en‐ couraging result, however, it was stated that the patient is still very young (20 years of age at

Other studies on younger patients have not had as good results as those reported by Capello though. Nizard *et al* (2008) [89] reported on ceramic-on-ceramic hips that had been implant‐ ed in a group of 101 patients (132 hips) younger than 30 years old (mean age: 23.4 years, range: 13 – 30 years). These joints were implanted from 1977 to 2004 and, because of this, different implant designs and modes of fixation were used. Of these 132 joints, 17 were re‐ vised for aseptic loosening leading to a survivorship of 82.1% at 10 years and 72.4% at 15 years. These survivorship rates are quite low and may create cause for concern. It was, how‐ ever, found that the higher rate of failures of joints replaced for treatment of slipped capital epiphysis or trauma influenced the survivorships greatly. Also, these artificial hip joints were implanted over a period of 26.5 years, during which time the ceramic materials have been improved and the fixation methods have changed. It is hoped that ceramic of the new generation with improved prosthesis design and mode of fixation will perform better and

From the results reported here it is clear that ceramic-on-ceramic hip joints have good tribolog‐ ical results: low friction, good lubrication and very low wear *in vitro* and *in vivo*. In addition to this, ceramic particles are biologically inert. Also, the fracture risk is relatively low. With good implant positioning these joints have the potential to perform incredibly well. These bearings, therefore, deserve to be high on the list for both primary and revision implants, especially for

the time of report) and, therefore, the need for revision surgery will be more than likely.

these small risks on the prosthesis performance.

550 Advances in Biomaterials Science and Biomedical Applications

**4. The younger patient**

with this material combination.

provide improved longer-term results.

**5. Overview**

Susan C. Scholes and Thomas J. Joyce

\*Address all correspondence to: susan.scholes@newcastle.ac.uk

School of Mechanical and Systems Engineering, Newcastle University, Newcastle-upon-Tyne, UK
