Four stem fractures in a 12-year follow-up study of 9,135 patients with Exeter hip stems at seven teaching facilities in Japan.

BACKGROUND: Although excellent long-term results have been reported for the Exeter stem, stem fracture is recognized as a rare complication. However, there have been no reports on the incidence and risk factors for stem fractures based on detailed population information. This study aimed to clarify the incidence of Exeter hip stem fracture based on detailed population information from seven Exeter stem teaching centers in Japan and to examine the risk factors for stem fracture. METHODS: A total of 8,499 primary total hip arthroplasties (THA) and 636 revision hip arthroplasties (revisions) performed at seven Exeter teaching hospitals between 1999 and 2021 were included and retrospectively investigated based on medical records. RESULTS: Stem fractures were identified in two primary THA (fracture rate: 0.02%) and two revision THA (fracture rate: 0.21%) cases. The stem length was ≤125 mm in three out of these four cases. Revision and 30 stem were the risk factors for stem fractures. Weight and body mass index (BMI) were not significantly associated with the occurrence of stem fractures. CONCLUSIONS: In Western countries, the incidence of Exeter stem fractures is reportedly 0.017-0.15% for primary THA and 0.99-1.21% for revision THA. In this study, the incidence of primary THA was 0.02%, which is similar to the lowest reported rate, whereas the incidence of revision THA was 0.21%, which is lower than that reported in previous studies. Revision surgery had the same risk factors as those reported in the West-namely, stem length ≤125 mm (except for the 30 stem) and BMI, which were not risk factors in Japanese patients.

Decennial trends in hip fractures over 20 years in Yamagata Prefecture, Japan.

BACKGROUND: Hip fracture is among the most common injuries in elderly people. We aimed to investigate the decennial trends in hip fractures in patients ≥65 years of age. METHODS: A questionnaire was distributed to all hospitals with a Department of Orthopaedic Surgery in Yamagata Prefecture to collect data on hip fractures occurring in 1996, 2006 and 2016. RESULTS: The response rate was 100%. The total numbers of hip fractures in 1996, 2006 and 2016 were 665, 1169 and 1,728, respectively (crude incidence: 258, 373 and 494 per 100,000 person-year, respectively). Injuries frequently occurred in the early morning and daytime morning in 1996. In contrast, they frequently occurred in activity times (e.g., morning and afternoon) in 2006 and 2016. Among the patients, 80-90% were injured by simple falls, and 70-80% were injured indoors. The incidence of trochanteric fractures was approximately 1.8-1.9 times greater than incidence of neck fractures in all years. Especially, trochanteric fractures in females of ≥90 years of age markedly increased. The rate of surgical treatment was the same in 1996 and 2006, but was lower in 2016. In 1996, the percentage of independent walkers at discharge and 1 year later was almost the same. In 2006 and 2016, the rate of independent walkers was low at discharge, but increased 1 year later. The rate of discharge to home decreased gradually. The combined percentage of patients discharged to home and to rehabilitation institutions in 2006 and the percentage of patients who entered the regional referral clinical pathway in 2016 were both approximately 70%, with no marked changes observed. CONCLUSIONS: Hip fractures, especially trochanteric fractures in super-aged females, increased. Discharge to home decreased, and the use of the regional referral clinical pathway was widespread. Ambulation ability was reduced at discharge, but improved after 1 year.

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.

BACKGROUND: The 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. METHODS: With 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. RESULTS: The 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. CONCLUSIONS: This 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.

Antibiotics-impregnated cement spacers in the first step of two-stage revision for infected totally replaced hip joints: report of ten trial cases.

BACKGROUND: Periprosthetic infection is one of the serious complications after total hip arthroplasty (THA). This study analyzed the perioperative and postoperative status of patients who underwent antibiotics-impregnated cement spacer technique in the first step of the two-stage revision. METHODS: Ten joints of the nine patients (mean age, 65 years; seven women, two men) received two-stage revision as a result of infection that appeared after primary THAs in seven joints, aseptic revision in one, and recurrent type in two. An antibiotics-impregnated cement spacer made by a mold system was applied in the femoral side of all joints. An acetabular spacer was made by hand using a cup gauge in eight joints with extensive tissue loss. RESULTS: The change of leg length after the first stage was -2.2 mm, and range of hip flexion was 72 degrees on average, respectively. Patients could walk with crutches after the first stage, except one patient with simultaneous infections of both hips and one with fracture of the cement spacer. One fracture of femoral cement spacer, and one dislocation of femoral spacer accompanied by fracture of acetabular cement spacer and curable recurrent infection, were found. In all cases of the second-stage procedure, the acetabular side was reconstructed with allogeneic bone graft with cross plate and that of the femur was by impaction bone grafting method. In the latest follow-up, reconstructed implants were stable. Seven patients could walk without any supportive devices and two could walk with the support of a T-cane. CONCLUSIONS: An antibiotics-impregnated cement spacer in the first step of the two-stage revision was effective not only to compensate tissue loss after removal of the implants and to minimize discrepancy of leg length, but also to contribute to improvement of perioperative and postoperative daily activities of the patient's life as well as treatment of the infection.

Cement removal and bone bed preparation of the femoral medullary canal assisted by flexible endoscope in total hip revision arthroplasty.

PURPOSE: The flexible endoscope was applied to cemented femoral medullary canal to obtain better visual field and assist surgical procedures in total hip revision arthroplasty. METHODS: Fifteen cases of failed cemented total hip joints were analyzed. Efficacy of cement removal was assessed, combined with degree of implant loosening and bone defect, postoperative radiographic findings, and perioperative status of the patients and complications. Status of the bone bed between bone and cement and that of bone grafting were also evaluated. RESULTS: The cement mantle was efficiently extractable in all cases under good exposure and with maintenance of efficient working space. Endoscopic time for cement removal was dependent on the status of the cement-bone interface and bone defect. Rigid and less loosened interfaces, as well as cases of minimal bone defect, required a longer time. However, it was effective to confirm the status of the bone bed during the procedure. Occult foreign-body reaction was detectable in three cases of unloosened interface under endoscopic inspection. Impaction bone grafting was performed in eight cases. The scope was also helpful to confirm the status of a grafted bone bed. Three fractures occurred, of which two cases revealed minor cement leakage and one required additional osteosynthesis with extensive approach. JOA Hip Score was improved, and the implants were stable at latest follow-up. Dislocation was found in two cases. Neither thromboembolic events nor infection was found. CONCLUSIONS: Cement removal in the femoral medullar canal was effectively performed not only in the cases of loose interface but also those of rigid and less-loosened interface under flexible endoscopic inspection. The scope could support cement removal in femoral revisions under good exposure and maintenance of working space, as well as confirmation of bone bed state. Although one case required an additional approach, application of the flexible endoscope has potential merit to contribute to less invasive total hip revision arthroplasty, possibly combined with other refined devices of cement extraction.

Inherited risk factors for deep venous thrombosis following total hip arthroplasty in Japanese patients: matched control study.

BACKGROUND: Inherited predisposing risk factors for deep venous thrombosis (DVT) have been clearly identified in Caucasians, but there are fewer reports evaluating these factors in the Japanese. This study was undertaken to assess the predisposing risk factors for DVT following elective total hip arthroplasty (THA) in Japanese patients. METHODS: We studied 60 patients who underwent THA. The study group consisted of 30 patients who developed DVT diagnosed by duplex sonography examination; the 30 patients who did not develop DVT served as a control group. They were matched in age, sex distribution, diagnosis (osteoarthritis secondary to dysplastic hip), and operation side(s) (bilateral or unilateral). Protein C, protein S, antithrombin III, and plasminogen activities and the plasma homocysteine level were measured. Three polymorphisms were screened for the factor V Leiden polymorphism, the factor II G20210A polymorphism, and the methylene tetrahydrofolate reductase C677T polymorphism. RESULTS: Plasma protein C activity was 82.39% +/- 14.24% in the DVT patients and 88.76% +/- 23.27% in the controls. Plasma protein C activity was significantly reduced in the study group, whereas other serologic and genetic analyses revealed no significant differences. CONCLUSIONS: Three genetic risk factors established in Caucasian patients are not valuable for evaluating DVT risk in Japanese patients. Reduced protein C activity may be a risk factor for DVT after THA.