Clinical and radiographic results for the Richards Modular Hip System prosthesis in total hip arthroplasty: average 10-year follow-up.

The clinical results of total hip arthroplasty using the Richards Modular Hip System prosthesis were evaluated in 41 patients (44 joints). The mean Harris hip score improved from 42 points before surgery to 82 after 1 year, 85 at 5 years, and 79 at the final examination. The average polyethylene wear rate was 0.09 +/- 0.07 mm/y. Forty joints (90.9%) achieved press fit in either of the proximal or the distal stem portion, and only 4 joints (9.1%) failed to achieve press fit in both the proximal and distal stem portions. Although the 10-year survival of the stem was 94.5% and no revisions of the stem were performed, osteolysis was found at high frequency at a distal stem. The high incidence of osteolysis has been the limiting factor in the long-term success of Richards Modular Hip System. Achievement of good canal fill in both the proximal and distal stem portions did not contribute to the good long-term result of the stem.

Reliability and validity of the Japanese Orthopaedic Association hip score.

BACKGROUND: The Japanese Orthopaedic Association (JOA) hip score has been widely used in Japan as a method to assess hip joint diseases. The JOA hip score consists of four subcategories: pain (Pain), range of motion (ROM), ability to walk (Gait), and activities of daily life (ADL). We present the first report to verify the reliability and validity of the JOA hip score. METHODS: A total of 123 patients with osteoarthritis of a unilateral hip and 29 patients with osteonecrosis of a unilateral hip were investigated. The JOA hip score was recorded by orthopedic surgeons in their offices. On the same day, each patient answered a Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) (Japanese version 1.2) by himself or herself. The SF-36 survey measures eight subscales. The internal-consistency reliability of the JOA hip score was evaluated by Cronbach's coefficient alpha. The validity of the JOA hip score was tested by Spearman's correlation coefficients between the four subcategories of the JOA hip score and the eight SF-36 subscales. RESULTS: When patients with osteoarthritis with conservative treatment were assessed by the JOA hip score, Cronbach's coefficient alpha was 0.70, demonstrating internal-consistency reliability. However, when the JOA hip score was used for other groups, Cronbach's coefficient alpha was <0.70, demonstrating the lack of internal-consistency reliability. Significant correlations were observed between Pain and bodily pain (r = 0.63), between Gait and physical functioning (PF) (r = 0.70), and between ADL and PF (r = 0.81), but not in any other combinations. CONCLUSIONS: We found that the JOA hip score is a reliable system only for patients with osteoarthritis of the hip with conservative treatment. The JOA hip score is a scaling system with convergent and discriminant validity for the assessment of physical function and pain.

ABCB1 C3435T and G2677T/A polymorphism decreased the risk for steroid-induced osteonecrosis of the femoral head after kidney transplantation.

Advances in transplantation technology have brought about great benefits to patients suffering from organ failure, but the problem still remains of complications induced by steroids used for post-transplant immunosuppression. Among the side-effects caused by steroids, non-traumatic osteonecrosis of the femoral head (ONF) constitutes a serious problem. The same protocol for steroid administration induces ONF in some patients, but not in others, indicating the presence of individual difference in steroid sensitivity. We hypothesized that this difference might be mediated by the drug-transport protein, P-glycoprotein (P-gp), and investigated the relationship between single nucleotide polymorphisms in the multidrug resistance gene 1 (ABCB1, MDR1) encoding P-gp and ONF. Subjects comprised 136 patients receiving kidney transplantation. Thirty patients developed post-transplant ONF. Genomic DNA was extracted from peripheral blood, and genotypes of ABCB1 C3435T (exon 26) and G2677T/A (exon 21) were determined by direct sequencing. Multivariate analyses based on clinical information were performed to determine the relationship between ABCB1 genotypes and ONF. The dose/concentration (D/C) ratios of tacrolimus were also determined to estimate the activity of P-gp in patients with different genotypes of ABCB1 C3435T (CC, CT, TT), and in those who did and did not develop ONF. The ABCB1 3435TT genotype showed a significantly lower incidence of ONF (adjusted odds ratio = 0.10, P = 0.034). The D/C ratio in the 3435TT genotype was significantly higher than that in the 3435CC genotype. The D/C ratio in patients developing ONF was significantly higher than in those patients who did not develop ONF. The results suggest increased activity of P-gp in patients with the 3435TT genotype and in those who did not develop ONF. The ABCB1 2677 homozygous variant type also showed a lower incidence of ONF (adjusted odds ratio = 0.26, P = 0.056). The 3435T and 3435C alleles were in linkage disequilibrium with the 2677T and the 2677G alleles, respectively, in the study population. An assessment of C3435T and G2677T/A polymorphisms preceding steroid treatment could be useful for predicting the resistance to ONF development.

Relationship between postrenal transplant osteonecrosis of the femoral head and gene polymorphisms related to the coagulation and fibrinolytic systems in Japanese subjects.

BACKGROUND: Nontraumatic osteonecrosis of the femoral head (ONFH) is one of the complications that may occur after renal transplantation. We investigated the relationship between the incidence of ONFH and polymorphisms in the genes for plasminogen activator inhibitor (PAI)-1, which is one of the major regulatory proteins of the fibrinolytic system, and 5,10-methylenetetrahydrofolate reductase (MTHFR), which is associated with the plasma levels of homocysteine in Japanese subjects. METHODS: Thirty-one patients with postrenal transplant ONFH and 106 patients without ONFH were selected. Genotypes of PAI-1 4G/5G and MTHFR C677T were determined by direct sequencing of genomic DNA. In addition, plasma PAI-1 antigen (Ag) levels and plasma total homocysteine (tHcy) levels at the steady state were measured. The relationships between the incidence of ONFH and these genotypes, as well as plasma levels of the gene products, were investigated. RESULTS: Plasma PAI-1 Ag levels were the highest in patients with the 4G/4G genotype, and plasma tHcy levels were the highest in patients with TT genotypes of MTHFR C677T. However, the relationship between the incidence of ONFHH and PAI-1 4G/5G or MTHFR C677T was not observed. The relationship between the incidence of ONFH and plasma levels of PAI-1 Ag or tHcy was not observed. CONCLUSIONS: Genotypes of PAI-1 4G/5G and MTHFR C677T or plasma concentrations of PAI-1 Ag and tHcy had no effect on the incidence of ONFH in Japanese subjects, unlike the results of studies performed in white subjects. The effect of genetic background on the pathologic conditions that developed in patients with postrenal transplant ONFH may differ according to race.

Coverage of the femoral head by the acetabular labrum in dysplastic hips: quantitative analysis with radial MR imaging.

Hip dysplasia is an important cause of osteoarthrosis of the hip, especially in Japanese. Recently, the role of the acetabular labrum in hip diseases has attracted the attention of researchers, but the condition of the labrum in the dysplastic hips has not been described. We used radial MRI to measure the degree of coverage of the femoral head by the acetabulum and the labrum, corresponding to 7 positions on the acetabular rim at every 15 degrees from anterosuperior 45 degrees via midsuperior to posterosuperior 45 degrees. 38 Japanese patients (51 hips) with dysplasia, and 11 healthy controls 122 hips) were studied. In the dysplastic hips, the labrum was larger than in the controls. We found no correlation between the coverage of the acetabulum in the anterosuperior positions and the size of the labrum among the dysplastic hips.

Initial change in transient osteoporosis of the hip on magnetic resonance images: a case report.

We report the case of a 29-year-old Japanese man with transient osteoporosis of the left hip (TOH) following contralateral TOH, paying special attention to the initial changes on MRI. MR images showed no abnormal findings 6 weeks before the clinical manifestation, but the images just after the onset depicted a linear abnormality equivalent to a subchondral insufficiency fracture. Both radiological findings and clinical symptoms disappeared completely without any surgical intervention within 10 months.

Effect of heat stimulation on viability and proteoglycan metabolism of cultured chondrocytes: preliminary report.

Thermotherapy has been applied to various joint diseases and injuries, but its direct effects on articular cartilage have remained unclear. The present study examined the effects on cell viability and metabolism by using the chondrocyte-like cell line HCS-2/8. The temperatures and durations of heat stimulation were 39 degrees, 41 degrees, 43 degrees, and 45 degrees C for 15 or 30 min. After heat stimulation of 41 degrees C or lower for 15 or 30 min, cell viability increased and proteoglycan metabolism was accelerated, whereas after stimulation at 43 degrees C or higher for 30 min the viability and metabolism decreased. These results indicate that appropriate heat stimulation positively affects cell viability and the proteoglycan metabolism of articular cartilage, whereas too much heat stimulation produces negative effects. Clinical efficacy is therefore determined by the overall thermal dose. When the appropriate combination of temperature and duration is found, thermotherapy for diseases and injury of articular cartilage can be highly useful in clinical practice.

Predictive value of magnetic resonance imaging in avascular necrosis following talar fractures.

Ischemic bone necrosis following talar fractures is a problematic complication and its early diagnosis is important. Patients with Hawkins Type II and III talar fractures received internal fixation using titanium alloy screws, and chronological bone changes were observed with Magnetic Resonance Imaging (MRI). With the Type II patient, Hawkins' sign was radiographically confirmed 2 months after the surgery. Furthermore, there were no changes of MR images for 2 years and a good clinical outcome was obtained. However, in the Type III patient, Hawkins' sign was negative and MRI revealed a low signal-intensity band on the talus 2 months after the surgery and then necrosis was radiographically confirmed; pain appeared 10 months later. These 2 cases suggest that MRI is a useful means for detecting bone necrosis with talar fractures in the early post-operative period.

Risk factors for nontraumatic osteonecrosis of the femoral head after renal transplantation.

We investigated risk factors for osteonecrosis of the femoral head (ONF) in renal transplant recipients, who are susceptible to the disease. Among 287 renal transplant recipients, 18 ONF patients with enough data were included, and 18 age- and sex-matched recipients without ONF were nominated as reference cases. Risk factors were analyzed using a conditional logistic regression method. There were no differences between the ONF patients and the reference cases regarding the types of immunosuppressant or the donor (living or cadaveric, father or mother, matching blood type and human leukocyte antigens). The daily oral steroid dosage (prednisolone 25.0 mg/day or more) and blood urea nitrogen level 2 months after transplantation were the only factors with relevance to the occurrence of ONF. We propose that oral steroid dosages should be low or reduced after renal transplantation, and acute rejection should be controlled with pulsed therapy.

Minimum 10-year radiographic follow-up of a cementless acetabular component for primary total hip arthroplasty with a bulk autograft.

We radiographically investigated 36 hips in 34 patients with osteoarthritis of the hip who had undergone total hip arthroplasty. Their mean age was 59.2 years (range 36-79 years), and the mean follow-up period was 11.2 years (range 10-14 years). The long-term outcome and the chronological changes in the bulk autograft were examined. The acetabular component of the prosthesis was a Lord-type threaded cup with a smooth surface. At follow-up, bone absorption was minor in 17 joints, moderate in 11, and major in 8. The hips with graft coverage of >==20% (group A) had a significantly higher loosening rate than hips with coverage of <<20% (group B) ( P << 0.05). The cup position changed markedly in group A. Our findings indicate that graft coverage should be less than 20% when a bulk graft is used together with a smooth-surfaced cementless cup.

Genetic analysis of steroid-induced osteonecrosis of the femoral head.

With advanced organ transplantation technology, steroid-induced osteonecrosis of the femoral head (ONF) is one of the most troublesome complications. Steroid sensitivity varies among individuals, and the involvement of polymorphism of various genes relating to steroid metabolism is suggested. The present study investigated the relation between single nucleotide polymorphism (SNP) on the DNA sequence of cytochrome p(450) and ONF development. The subjects were 80 renal transplant patients. Genome DNA was obtained from the peripheral blood, and SNP analyses for CYP3A4, CYP2D6, and CYP2C19 were conducted using various methods: direct sequencing, polymerase chain reaction restriction fragment length polymorphism, and DNA Chip. The relation between ONF development and SNP was statistically analyzed. It is useful if the generating risk judged according to SNPs to prevention of steroid-induced ONF is possible. This time, SNPs, which are clearly related to ONF, were not accepted, although the possibility that SNP related to steroid metabolism is involved in ONF development is important. We think that it is necessary to examine this area more closely.