Seneki Kobayashi

Poor bone quality or hip structure as risk factors affecting survival of total-hip arthroplasty

BACKGROUND The principal long-term complication after total hip arthroplasty (THA) has been aseptic fixation failure. Many hip prostheses and operative techniques have been developed to improve outcomes, but few measures have been taken to cope with poor bone quality or hip structure. We assessed risk factors for aseptic fixation failure after THA. METHODS We assessed, by multivariate analysis, survival of 405 primary Charnley THAs to identify risk factors for aseptic fixation failures. We also investigated risk factors for development of rapid polyethylene wear (penetration depth of the femoral head into the socket polyethylene > or = 2 mm/year) FINDINGS In the entire series of 405 THAs, with use of radiographic fixation failure or revision for a loose socket as the endpoint, development of rapid polyethylene wear and the preoperative diagnosis of atrophic osteoarthrosis (defined by scarce osteophyte formation) were identified as risk factors for socket loosening (p < or = 0.02). A medullary canal with an unfavourable geometry (a stovepipe canal, Nobles canal-flare index < 3.0) was the only risk factor for femoral fixation failure (p < or = 6.7x10(3)). The only variable related to development of rapid polyethylene wear was the type of steel used in the femoral prosthesis--Ortron 90 prostheses significantly lowered the rate of development of rapid wear from 12.7% to 0.4%. In the 248 THAs in which these femoral prostheses were used, socket survival was affected only by the preoperative diagnosis of atrophic osteoarthrosis (for radiographic fixation failure and revision, p=4.0x10(-5) and p=0.042, respectively). INTERPRETATION In THA, the critical risk factors are poor bone quality, which manifests as atrophic osteoarthrosis, for socket survival and poor bone structure for femoral-prosthesis survival. To ensure longer durability of THAs, these factors should be assessed further and efforts, especially biological initiatives, should be made to resolve them.

Phosphodiesterase inhibitors, pentoxifylline and rolipram, increase bone mass mainly by promoting bone formation in normal mice

The administration of either Pentoxifylline (PTX), a methylxanthine derivative and an inhibitor of cyclic AMP (c-AMP) phosphodiesterases (PDEs), or Rolipram, an inhibitor specific to type-4 PDE (PDE4) in normal mice, significantly increased both cortical and cancellous bone mass. Vertebrae and tibiae from mice treated with PTX or Rolipram were analyzed by means of bone densitometry and histomorphometry. The results revealed that both PTX and Rolipram increased bone mass in normal mice mainly through the acceleration of bone formation. These findings suggest that both PTX and Rolipram can enhance physiological bone formation and thereby increase bone mass in normal mice. The possibility that these agents may be of value for the treatment of osteoporosis is discussed.

Factors affecting aseptic failure of fixation after primary Charnley total hip arthroplasty. Multivariate survival analysis.

Multivariate survival analysis with use of the Cox proportional-hazards model was applied to a consecutive series of 293 primary Charnley total hip arthroplasties performed on 246 patients. The purpose of the analysis was to identify risk factors for, and to quantitate their effects on, aseptic failure of fixation. The duration of follow-up ranged from one month to twenty-three years (average, thirteen years). The end point of survival was defined as radiographic evidence of failure of fixation or as a revision operation. Failure of fixation of the acetabular component was defined as complete demarcation or migration. Failure of the femoral component was defined as progression of at least one of five postoperative signs (subsidence, demarcation of the cement, separation of the component from the cement, fracture of the cement, and endosteal cavitation) or as the occurrence of at least two of these signs. Twenty-four specific items of data for each acetabular component and thirty specific items for each femoral component formed the sets of variables for the analysis. With use of radiographic evidence of failure as the end point, the sixteen-year rates of survival (with 95 per cent confidence interval) were 83.6 ± 5.6 per cent for the acetabular components and 90.9 ± 4.1 per cent for the femoral components. With use of revision as the end point, the sixteen-year rates of survival were 92.3 ± 4.0 per cent and 95.6 ± 3.2 per cent, respectively. The most important risk factor affecting radiographic loosening of the acetabular component was rapid wear of the polyethylene (0.2 millimeter or more annually), followed by the classification of the osteoarthrosis (as hypertrophic, normotrophic, or atrophic) according to the extent of osteophyte formation. The sockets in the hips that had hypertrophic osteoarthrosis survived longer than those in the other two groups. Survival of the acetabular component as determined on the basis of revision was affected only by rapid wear of the polyethylene. Survival of the femoral component, with either radiographic failure of fixation or revision as the end point, was affected by an unfavorable geometry of the medullary canal (a so-called stovepipe canal or a large canal). Patients who have rapid wear of the polyethylene, little osteophyte formation, or an unfavorable geometry of the canal should be followed carefully. These risk factors warrant additional evaluation.

Total Hip Arthroplasty with Bulk Femoral Head Autograft for Acetabular Reconstruction in Developmental Dysplasia of the Hip

Background: 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.Methods: 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.Results: 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.Conclusions: 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.Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Comparative Study of Total Hip Arthroplasty Between Younger and Older Patients

Ten- to 20-year (average, 14 years) results of primary Charnley low friction arthroplasties performed in patients 50 years of age or younger (55 sockets and 53 femoral prostheses) were compared with those in patients older than 50 years (273 sockets and 273 femoral prostheses). The incidence of radiologic loosening of the socket, including revision cases, was higher in the younger (29.1%) than in the older patients (14.3%). The revision rate for aseptic loosening of the socket was higher in the younger (20%) than in the older group (4%). This poor performance of the socket may be attributable to the higher incidences of rheumatoid diseases and accelerated polyethylene wear in the younger patients. In contrast, only 3.8% of the femoral prostheses were radiologically loose, and none of them were revised in the younger patients. These figures were comparable with those in the older patients. Quality or structure of bone available for implant fixation may be important for the durability of the arthroplasty. It was considered inferior on the acetabular side and better on the femoral side in the younger patients than in the older. Continued use of the cemented Charnley femoral prostheses can be justified in young patients, although further research is required for the socket problem.

Arthroscopic reduction and fixation of a completely displaced fracture of the intercondylar eminence of the tibia

A simple method of arthroscopic reduction and fixation of a fracture of the intercondylar eminence of the tibia is described. A 23-year-old man with a completely displaced (Type IIIB) fracture was treated with arthroscopy. A satisfactory reduction was achieved by releasing the medial meniscus, which was entrapped in the fracture site. Link dynamic staples (W. Link, Hamburg, Germany) were used to firmly fix the fracture when the guide tube came downward from the medial mid-patellar portal. The secure fixation of the fragment and the prevention of the need for an arthrotomy facilitated early functional rehabilitation. One year after surgery the patient had a stable, painless joint with a full range of motion. The described method is technically straight-forward and can provide secure fixation of a bone fragment. The Link staples are useful in the fixation of a displaced fracture of the intercondylar eminence of the tibia.

Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ): a patient-based evaluation tool for hip-joint disease. The Subcommittee on Hip Disease Evaluation of the Clinical Outcome Committee of the Japanese Orthopaedic Association

BackgroundThe Japanese Orthopaedic Association Hip Score is widely used in Japan, but this tool is designed to reflect the viewpoint of health-care providers rather than that of patients. In gauging the effect of medical therapies in addition to clinical results, it is necessary to assess quality of life (QOL) from the viewpoint of patients. However, there is no tool evaluating QOL for Japanese patients with hip-joint disease.MethodsWith the aim of more accurately classifying QOL for Japanese patients with hip-joint disease, we prepared a questionnaire with 58 items for the survey derived from 464 opinions obtained from approximately 100 Japanese patients with hip-joint disease and previously devised evaluation criteria. In the survey, we collected information on 501 cases, and 402 were subjected to factor analysis. From this, we formulated three categories—movement, mental, and pain—each comprising 7 items, for a total of 21 items to be used as evaluation criteria for hip-joint function.ResultsThe Cronbach’s α coefficients for the three categories were 0.93, 0.93, and 0.95, respectively, indicating the high reliability of the evaluation criteria. The 21 items included some related to the Asian lifestyle, such as use of a Japanese-style toilet and rising from the floor, which are not included in other evaluation tools.ConclusionsThis self-administered questionnaire may become a useful tool in the evaluation of not only Japanese patients, but also of members of other ethnic groups who engage in deep flexion of the hip joint during daily activities.

Sequential changes in periprosthetic bone mineral density following total hip arthroplasty: a 3-year follow-up

Abstract 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.

Factors influencing survivorship of the femoral component after primary low-friction hip arthroplasty

Two hundred sixty-seven consecutive primary low-friction arthroplasties, followed for 5-18 years after surgery, were studied to assess the factors influencing survivorship of the femoral component, using the Kaplan-Meier method. The end point of survivorship was defined radiographically in two ways: incipient failure (subsidence of the femoral component of > or = 2 mm) and definite failure (progressive change of position). Twenty-two femoral components developed incipient failure, and twelve of these advanced to definite failure. A canal filling ratio of the stem of > or = 75%, cement extent distal to the stem tip of > or = 1 cm, use of an intramedullary bone plug, and an exaggerated valgus alignment of the stem correlated positively with survivorship of the femoral component. Calcar resorption and atrophy of the femoral cortex after surgery were associated with aseptic loosening of the femoral component.

Long term bone remodeling around the Charnley femoral prostheses

Femoral bone remodeling after total hip replacement was studied by following patients who received 326 Charnley femoral prostheses for 10 to 20 years (mean, 13.3 years). The radiographic state of bone remodeling was visually assessed and measured with a digitizer. Demineralization that started proximally and then progressed distally caused cortical thinning, which correlated with widening of the intramedullary canal, not with changes that developed in the periosteal width, and occurred in the medial femoral neck, around the proximal half of the stem, and around the distal half in 87%, 33%, and 10%, respectively. Cortical thinning around the distal half of the stem was always accompanied by proximal thinning, and extensive cortical thinning (both proximal and distal) correlated with both lower clinical scores and radiologic loosening of the femoral prosthesis. A low canal flare index of Noble, a large canal width, and a patient age of 60 years or more were risk factors for extensive cortical thinning. Accelerated polyethylene wear was related to resorption of the medial femoral neck but not to cortical thinning or radiological loosening. Cortical thickening occurred only around the distal half of the stem in 29%. These findings establish a basis for the performance of cemented femoral prostheses, and allow comparison of bone remodeling when evaluating other femoral prostheses.