Liver transplantation has improved the survival of patients with end stage liver disease. This improvement is mainly due to the advancement in patient selection, preoperative and postoperative care, surgical technique and immunosuppressive drugs1). Cyclosporine A is a potent inhibitor of cytotoic T-cells, and its use has increased the success of organ transplantation. Despite these advances, prednisone is still an important agent and osteonecrosis is a serious complication in this group of patients. The incidence of osteonecrosis was variously reported, from 2% to 8.2% after liver transplantation. One long-term study found no liver recipients developing osteonecrosis. Another study revealed a 1% incidence of osteonecrosis in a liver transplant population2). As the rates of success of organ transplantation continue to increase, more patients who have a liver transplant will become candidates for joint replacement due to osteonecrosis. However, there are only two reports in English literature about total hip arthroplasty (THA) for osteonecrosis of the femoral head following liver transplantation, and especially, there has not been such a report in Asian countries3,4). The authors report two patients with liver transplantation, who underwent total hip arthroplasty. The patients were informed that the data from the cases would be submitted for publication, and gave them consent.

Annually more than 5,000 liver transplantations are performed in the United States. The overall long-term survival has apparently improved despite coexisting morbidities, old age and high BMI of the operated patients, higher degree of HLA mismatch and long waiting time5). In Korea, 2,345 orthotopic liver transplantations were performed in 24 institutes form March 1988 to December 2004. One year survival after liver transplantation, deceased donor liver transplantation was 62%, and living donor was 80% in 1998, but the survival has improved to 76% in deceased donor liver transplantation and 83% in living donor liver transplantation6). In the literature review, we find that there are a few studies which reported on the prevalence of osteonecrosis of the femoral head and results of total hip arthroplasty following liver transplantation (Table 1). Papagelopoulos et al.7) reported that 23 (8.1%) of 285 liver transplant recipients developed symptomatic osteonecrosis of the femoral head following liver transplantation, and only 5 patients required total hip arthroplasty. There were no serious complication of THA. Taillandier et al.1) reported a 1 case of THA which was done for osteonecrosis of the femoral head. Levitsky et al.8) reported 3 cases of THA following liver transplantation, and there were no complication. Lieberman et al.9) reported that 4 (2%) of 203 patients were diagnosed with osteonecrosis of the hip after that surgery and there was no patients who required total hip arthroplasty, and these authors noted that this condition was rare and would not require MRI screening. Tannenbacum et al.3) reported that 4 cases of total hip arthroplasty for degenerative osteoarthritis of the hip joint following liver transplantation and 1 case of them required revision arthroplasty because of aseptic loosening.

Aseptic necrosis of the femoral head is also disabling complication of renal transplantation. Although its incidence has markedly decreased during the last decades as a result of the lowered steroid dosage secondary to the introduction of cyclosporine in immunosuppressive regimens, it still occurs in 4.5% of renal transplantation recipients10).

Management of osteonecrosis of the femoral head following solid organ transplantation procedures is based on the stage of the disease. Treatment regimens for osteonecrosis of the femoral head include nonsurgical management, arthrodesis, bone grafting and muscle pedicled bone graft, rotational osteotomy and total hip arthroplasty. As the success rate of solid organ transplantation continues to rise, more patients will be expected to become a candidate to joint replacement surgery. However, concerns still exist regarding the vulnerability of these patients to certain complications such as postoperative infection due to chronic immunosuppression and mechanical implant failure due to poor bone quality.

The immunosuppressive medication should be given at the scheduled times and no dose should be withheld. In a case of sepsis, a decrease in the immunosuppressive regimen is recommended. In patients who are stable after surgery, daily levels of cyclosporine and tacrolimus and liver function tests are unnecessary. It is sufficient to control the immunosuppressive medication level after surgery and to repeat in patients with variation greater than 25% of the baseline.

Corticosteroids are considered as first line armamentarium in the post-transplant immunosuppression. The introduction of azathioprin, which is a purin synthesis inhibitor, and cyclosporin A, which is a potent cytotoxic T-cells inhibitor, in early 1980s minimized the need for high corticosteroid doses and improved the overall graft survival and reducing the rejection rate. Further advancement was achieved by the discovery and the use of agents such as Tacrolimus which inhibits T-lymphocyte signal transduction and interleukin-2 transcription, and Sirolimus which inhibits the response to interleukin-2 thereby blocking the activation of T- and B-cells. In our cases, first case patent has been administrated 2.5 mg of tacrolimus and 3,000 mg of mycophenolate mofetil per day as immunosuppressive agents and second case patient has been administrated 15 mg of prednisolone per day as immunosuppressive agents.

Hamburg et al.4) reports that the bone mass decreases following liver transplantation, especially in the first 3 months, and with an accompanying high fracture rate in the first 6 months. This accelerated bone loss occurring in the early period after transplantation depends on several factors : initial high-dose steroid therapy, malnutrition, immobilization, and cyclosporine therapy. However, vertebral bone marrow density is gradually restored to normal within 2 or 3 years after liver transplantation, resulting in normalization of hepatic function. The transplanted liver can be taken to be the most important factor in the improvement of bone marrow density, a general catabolic state having been replaced by an anabolic state by successful liver transplantation.

These patients have traditionally been approached with great hesitancy because of their compromised immune status and poor bone stock secondary to the use of prednisone. However, total joint arthroplasty of the hip to date has been safe and effective in the management of symptomatic osteonecrosis in liver transplant recipients5). Despites the theoretical risks of high infection rates and inferior bone quality associated with joint arthroplasties in solid organ transplant recipients, good to excellent results of knee, shoulder and ankle replacements performed in patients with renal, hepatic, cardiac or lung transplantation have been reported. Although there was no infection in our cases, Papagelopoulos et al.7) reported 1 case of wound infection after THA in liver transplantation patients. It seems that special perioperative preparations is not necessary for wound infection, but there are still risk of wound infection in liver transplantation patients exist, so much caution for these complications are needed. Antibiotics and thrombosis prophylaxis would be given as in standard arthroplasty operations. The relatively young age of patients should be considered when choosing the type of implants and the method of fixation. Levitsky et al.8) performed a retrospective analysis on 203 liver transplant recipients who had joint arthroplasty at a single teaching institution between 1986 and 2002, and the authors concluded that joint arthroplasties may be safely and successfully performed in liver transplant recipients. These patients are certainly at increased risk for anesthesia, but with proper management and careful monitoring using the standard patient anesthesia protocol, the risk of anesthesia can be reduced to reasonable levels.

Increased numbers of liver transplantations and improved patient longevity are likely to cause a sustained increase in the incidence of osteonecrosis of the femoral head. Hence the number of relatively young patients for total hip arthroplasty will increase. This is a rare report where mini-2-incision total hip arthroplasty was done for osteonecrosis of the femoral head following liver transplantation in an Asian patient.