Obesity is a risk factor for knee arthritis. Total knee arthroplasty is the definitive surgical treatment of this disease. Therefore, a high percentage of subjects treated are overweight. Since 2000 in the Emilia-Romagna Region the Register of Orthopedic Prosthetic Implantology, RIPO, has recorded data of all the primary and revision operations performed on the knee; height and weight of patients at the time of surgery have also been recorded.

Osteolytic lesions due to wear debris are the major long-term problem associated with total hip replacement1. To avoid wear debris, hard-bearing-surface total hip prostheses with improved tribological properties have been introduced into surgical practice. Ceramic surfaces have had some promising long-term results2, and modern metal-backed alumina cups have been associated with very good clinical results3-5. Alumina has excellent tribological properties and a very high Young's modulus that leads to very good compression strength, but it has poor bending strength: it has no way to deform6. This means that ceramic can break without warning. Under normal physiologic conditions, modern ceramics never reach their fatigue limit, so ceramic head fractures are rare (a rate of 0.004%7 in one study). In contrast, ceramic liner fractures are not well recognized, and their frequency could be underestimated (Fig. 1). In addition, it is difficult to identify patients who are at risk because liner fractures can be due to multiple causes: dislocation, impingement, malpositioning, and microseparation8,9. Fig. 1 A ceramic liner fracture. The diagnosis is often difficult to make on the basis of standard radiographs. A fragment of ceramic is visible near the calcar (arrow). The liner was found to be fractured (arrow) at revision surgery. While many efforts have been made to improve the ceramic manufacturing process and the surgical technique for inserting ceramic components10, little has been reported regarding the early diagnosis of ceramic fracture. When a ceramic fracture involves the liner and is the consequence of repeated microtrauma, the diagnosis is rarely made early, except when ceramic fragments are visible on radiographs. Moreover, decision-making regarding revision surgery after a ceramic-on-ceramic prosthesis has failed is difficult: the ceramic fragments that have spread into the periarticular space are abrasive and …

Revision of a total hip arthroplasty due to fracture of a ceramic component is rare. The fracture rate of ceramic components has been reported to be between 0.004%1 and 0.05%2 for femoral heads and between 0.013%2 and 1.1%3 for acetabular liners. Nevertheless, this problem is occurring more frequently because of the increasing use of ceramic total hip replacements. Revision arthroplasty performed because of a fractured ceramic component carries a high risk of failure: the fragments of the failed component are sharp and harder than metal; if left in the articular space, these fragments would act as an abrasive paste, and the use of a metal head against a polyethylene liner in the revision arthroplasty would quickly lead to catastrophic wear and failure of these new total hip implants4-6 (Fig. 1). Thus, revision arthroplasty performed because of a fractured ceramic component is difficult and the failure rate has been reported to be as high as 31%6. Fig. 1 Early failure of a revision arthroplasty performed because of fracture of a ceramic femoral head. The aims of the present study were to evaluate the outcome of revision total hip arthroplasty performed specifically to treat fracture of a ceramic component, to identify technical factors affecting the outcome, to propose some tips and tricks to make the process of revising a total hip arthroplasty for this reason easier, and to suggest guidelines for the treatment of a ceramic component fracture. From 1990 to 2009, 8022 primary ceramic hip prostheses were implanted at our institute; 3275 (40.8%) were in men and 4747 (59.2%) were in women. Additional patient demographic information is given in Table I. Kaplan-Meier curves with revision for ceramic fracture as the end point were computed to evaluate the rate of ceramic fracture. The analysis …