Young Kyun Woo

Oncogenic osteomalacia associated with soft tissue chondromyxoid fibroma

Oncogenic osteomalacia is a rarely described clinical entity characterized by hypophosphatemia, phosphaturia, and a low concentration of 1,25-dihydroxyvitamin D(3). It is most often associated with benign mesenchymal tumor and can be cured with surgical removal of the tumor. In this paper, we present a case of oncogenic osteomalacia caused by chondromyxoid fibroma in the soft tissue of the sole of the foot in a 56-year-old woman.

Average 10.1-year follow-up of cementless total knee arthroplasty in patients with rheumatoid arthritis

BACKGROUND Total knee arthroplasty (TKA) using a cemented technique has been recommended in patients with rheumatoid arthritis owing to the initial stability of the fixation and long-term durability of the components; however, similar long-term follow-up results have been reported in patients who have undergone cementless TKA. The purpose of this study was to evaluate the radiologic and clinical outcomes of cementless TKA in patients with rheumatoid arthritis. METHODS We enrolled patients undergoing cementless TKA from March 1990 to February 2000. Clinical and radiologic evaluations were performed using the Knee Society clinical rating system and radiographic evaluation and scoring system. RESULTS We included the cases of 112 patients who underwent 179 cementless TKA procedures in our analysis. Their mean age was 62.3 years, and the mean follow-up period was 10.1 years. The final survival rate was 0.968 at the 15.5-year follow-up. Regarding radiologic results after surgery, the mean total valgus angle was 6.7°, the mean femoral flexion angle was 97.5° and the mean tibial angle was 89.2° on the anteroposterior radiographs. On the lateral films, the mean femoral flexion angle was 1.6° and the mean tibial angle was 89.2°. At the last follow-up, the mean total valgus angle was 6.5°, the mean femoral flexion angle was 97.4° and the mean tibial angle was 89.1°, as seen on the anteroposterior view. On the lateral views, the mean femoral flexion angle was 1.4° and the mean tibial angle was 89.0°. Regarding the clinical outcome, the mean knee score and function score on the Knee Society clinical rating system were also enhanced from 47.5 and 43.6, respectively, before the operation to 91.2 and 82.3, respectively, at the last follow-up. CONCLUSION On radiologic and clinical follow-up of cementless TKA for patients with rheumatoid arthritis, there were no serious complications, and the results of the operation were satisfactory with improvement in range of motion and clinical symptoms.

Long-term clinical and radiological outcomes of hybrid total knee arthroplasty

OBJECTIVES The purpose of this study was to evaluate the clinical effectiveness and radiological results of hybrid total knee arthroplasty (TKA). METHODS This study recruited 105 patients (169 cases) who underwent hybrid TKA for osteoarthritis and rheumatoid arthritis from 1999 to 2002. Maxim (Biomet Inc., Warsaw, IN, USA) prosthesis was used, and average follow-up was 8.6 years. Radiologically, femorotibial angle was measured in a standing anteroposterior (AP) view, and a femoral flexion angle and a tibial angle were measured using the Knee Society roentgenographic evaluation and scoring system. Radiolucent lines were detected at the last follow-up. Clinically, range of joint motion and the Knee Society clinical rating system scores were evaluated. RESULTS The femorotibial angle was improved from varus 4.5° to 6.4° at the last follow-up. The femoral flexion in an AP view at the postoperative and last follow-up was 96.5° and 95.7°, respectively, and the tibial angle was 89.1° and 88.7°, respectively. In lateral view, the femoral flexion was 2.6° and 2.7°, respectively, and the tibial angle was 88.4° and 87.8°, respectively. Total scores of radiolucencies were 4 points or less in all cases, and the average width was 1.1 mm. Flexion contracture was improved from 10.0° to 3.5°, and further flexion was increased from 110.5° to 130.4°. Knee score and function score were also enhanced from 47.6 and 46.8 preoperatively to 89.7 and 88.4 after the operation, respectively. CONCLUSION Hybrid technique for TKA can be effective clinically and radiologically on longterm follow-up.

Arthroplasty of the hip in patients with aplastic anemia.

Background: Patients with aplastic anemia are now living longer and therefore are at increased risk for the development of osteonecrosis of the hip. However, studies on the results of arthroplasty for the treatment of osteoarthritis of the hip in patients with aplastic anemia are lacking. Methods: Twenty-six primary hip prostheses (one bipolar prosthesis fixed with cement, two bipolar prostheses fixed without cement, three hybrid total hip prostheses, and twenty total hip prostheses fixed without cement) were implanted, between March 1990 and May 1992, in nineteen patients who had been diagnosed with aplastic anemia. A specific prospective protocol was followed for the perioperative transfusion of platelets and blood. Twenty-five hips were replaced because of osteonecrosis of the femoral head, and one was replaced because of a femoral neck fracture. The patients were followed prospectively, with preoperative and serial postoperative Harris hip ratings as well as radiographs, for a minimum of six years or until death. Results: No patient had excessive perioperative bleeding or a postoperative infection. After a mean duration of follow-up of seventy-nine months (range, seventy-two to ninety-five months), two patients had died with the original implant in place. No patients were lost to follow-up. The mean Harris hip score was 55 points (range, 42 to 68 points) preoperatively and 87 points (range, 56 to 95 points) at the time of the latest follow-up. At the time of this writing, no hip had been revised. One patient with a bipolar prosthesis had radiographic evidence of femoral loosening and will probably require revision. A second patient had some medial protrusion of a bipolar prosthesis, with mild symptoms. All of the acetabular components that had been fixed without cement and all of the other femoral components appeared to be stable on radiographs after a minimum of seventy-two months of follow-up. Conclusions: Total hip arthroplasty can be performed safely in patients with aplastic anemia. In the present intermediate-term study, the durability of implant fixation was maintained and the clinical results demonstrated a sustained increase in function of the hip.