Seneki Kobayashi

The 2006 version of the guideline for prophylaxis and treatment of osteoporosis recommends vitamin K(VK)supplementation in the state of its deficiency. As VK(2) gained grade B in all aspects in the guideline, single use of the drug is limited. VK(2) may be used concurrently with other drugs in the treatment of osteoporosis. In this paper, the results of our concurrent use of two of vitamin D(3), VK(2), and EHDP are summarized, and the combined therapy including VK(2) will be reviewed.

Patients with idiopathic osteonecrosis of the femoral head (ION) are relatively younger (usually in their 30s to 50s) than those with osteoarthrosis (OA) , and usually have higher activity levels. When the necrotic area is large, or when advanced OA has developed, hemiarthroplasty or total hip arthroplasty (THA) are considered. When indicating these implant surgeries, age and life style of patients should be considered in selecting type of surgery and implant. In our previous study, THA was superior in durability to hemiarthroplasty in the entire series of ION patients and in the patients with stage 2 or 3 ION (without secondary OA) . As implants used for these surgeries have been improved, we are currently monitoring these implant surgeries with special interest in their durability.

Excessive polyethylene wear is recognized as one of the most important factors affecting the durability of total knee arthroplasty; however, bearing surface wear is a multifactorial problem. The purpose of this study was to identify factors for polyethylene wear and failure in primary posterior cruciate-retaining (PCR) total knee arthroplasty (TKA) in two disparate cohorts (American and Japanese). Seventy-three total knee arthroplasty operations were performed on 48 Japanese patients, and 76 on 63 American patients with noninflammatory arthritides. All patients were evaluated clinically and radiographically using a total joint arthroplasty database. Age, weight, diagnosis, Knee Society patient category, prosthesis size, insert thickness, alignment, polyethylene wear, osteolysis, Knee Society knee score, Knee Society pain score, and radiographic and clinical survivorship were evaluated. Seventy-three Japanese TKAs were followed for a mean of 6.6 years (range, 2.0-10.6). Three (4.1%) Japanese patients required revision. Seventy-six American TKAs were followed for a mean of 9 years (range, 2-10.2). Two (2.6%) American patients required revision. The American patients were significantly older, heavier, male predominant, and required larger size implants. The Japanese patients were significantly more female predominant and had a significantly less postoperative arc of motion. Knee Society knee and pain scores, survivorship, average total polyethylene wear, and annual wear rates were not different among the two cohorts. PCR TKA had similar survivorship in disparate cohorts of Japanese and American total knee arthroplasty patients despite smaller stature patients in the Japanese cohort. Cultural, gender-specific, and morphologic differences need to be considered for knee implant design. However, survivorship and polyethylene wear rates appear to be independent of these factors in disparate populations.

The long-term results of total hip arthroplasty performed with cement and use of a bulk autograft for acetabular reconstruction in patients with developmental dysplasia of the hip have varied considerably. We evaluated the results of total hip arthroplasties performed with acetabular bulk autograft to identify the factors that influence the results of this procedure. Acetabular roof defects secondary to developmental dysplasia of the hip were reconstructed with a bulk femoral head autograft at the time of total hip arthroplasties performed with use of the Charnley technique and prosthesis. Thirty-seven hips in thirty patients (mean age at the time of the operation, fifty-seven years) were followed for ten to twenty-six years (mean, nineteen years). The Crowe classification of hip subluxation or dislocation was Group II for sixteen hips, Group III for seventeen, and Group IV for four. Coverage of the socket by the graft ranged from 5% to 49% (mean, 33%). Twenty-nine sockets were located within the true acetabulum, and eight were placed more proximally. At the time of the latest follow-up, all of the patients had an excellent clinical result, all of the grafts had united, and no hip had radiographic evidence of failure of the fixation. We found that total hip arthroplasty performed with cement and use of a bulk autograft to reconstruct an acetabulum with severe bone deficiency secondary to developmental dysplasia of the hip can provide long-term success in patients forty-eight years of age and older when coverage of the socket by the graft does not exceed 50%. When it is not possible to achieve >50% coverage of the socket by the ilium at the level of the true acetabulum, more proximal placement of the socket to obtain adequate coverage is recommended.

Bulk autograft to identify the factors that influence the results of this procedure....

We sequentially measured the periprosthetic bone mineral density (BMD) of the femur after cementless total hip arthroplasty, using dual-energy X-ray absorptiometry, over a 3-year period. The periprosthetic bone was divided into three regions (proximo-medial, middle, and distal to the prosthetic stem). After the insertion of a fully porous coated stem in 21 patients, the BMD was measured within 3 weeks, and 6, 12, 24, and 36 months after surgery. At 6 months, all zones showed a decrease in BMD relative to the BMD within 3 weeks, but subsequently the BMD was unchanged. The lower the BMD within 3 weeks of surgery, or the lower the body weight, the higher the percent loss of BMD at 6 months.

Total hip arthroplasty can be performed successfully using cement or cementless technology. Cemented femoral stems can achieve enduring long-term suvivorship as long as meticulous surgical technique is utilized and patient selection is appropriate. Cemented acetabular components should only be utilized in patients with less than 10 years of remaining life expectancy. Critical risk factors for cemented total hip arthroplasty include atrophic osteoarthrtis on the acetabular side and unfavorable femoral geometry for the femoral stem such as "the stove-pipe" canal. Rapid polyethylene wear and osteolysis are rarely seen in contemporary cemented total hip arthroplasty performed with a smooth, tapered, collarless femoral stem with a highly polished head and a well-designed acetabular component.