Changes in the lateral pillar classification in Perthes' disease.

The purpose of this study was to examine the correlation between the changes in the lateral pillar grades and the factors influencing such changes. We reviewed 102 patients with Perthes' disease. Changes were observed in 32 (31%) hips. The percentage of the changes in each treatment group showed significant differences. Patients with extensive involvement showed significantly more changes. There was no difference in the age at the onset. We recommend that treatment methods be used that more effectively relieve the mechanical force on the capital femoral epiphysis for patients with extensive involvement regardless of the age at the onset.

The minimally invasive plate osteosynthesis (MIPO) technique with a locking compression plate for femoral lengthening.

A minimally invasive plate osteosynthesis technique using a locking compression plate (LCP) has been used widely in trauma cases. Its advantages are that the MIPO technique does not interfere with the fracture site and thus provides improved biological healing, and that the LCP has excellent angular stability. Its use in bone lengthening, however, has not been established. In such cases, it is desirable to shorten the external skeletal fixation period as much as possible. Here, the MIPO technique using an LCP was applied to femoral distraction osteogenesis in an attempt to shorten the external skeletal fixation period. For femoral lengthening, the MIPO technique was performed in 2 stages. Orthofix external fixators (Orthofix, England) were used to insert screws from the anterolateral side rather than from the lateral side of the femur for bone lengthening. When sufficient callus formation was detected postoperatively at the site of bone lengthening, and the absence of infection was ensured, limb draping was performed, including a whole external fixator, and then the MIPO technique was applied with an LCP.In 3 cases (5 limbs), the average duration of external skeletal fixation was 134 days, the average external-fixation index was 24 days/cm, and the average consolidation index was 22 days/cm. The MIPO technique using an LCP made it possible to shorten the external skeletal fixation-wearing period in femoral lengthening.

Promotion of bone regeneration by CCN2 incorporated into gelatin hydrogel.

CCN family protein 2/connective tissue growth factor (CCN2/CTGF) is a unique molecule that promotes the entire endochondral ossification process and regeneration of damaged articular cartilage. Also, CCN2 has been shown to enhance the adhesion and migration of bone marrow stromal cells as well as the growth and differentiation of osteoblasts; hence, its utility in bone regeneration has been suggested. Here, we evaluated the effect of CCN2 on the regeneration of an intractable bone defect in a rat model. First, we prepared two recombinant CCN2s of different origins, and the one showing the stronger effect on osteoblasts in vitro was selected for further evaluation, based on the result of an in vitro bioassay. Next, to obtain a sustained effect, the recombinant CCN2 was incorporated into gelatin hydrogel that enabled the gradual release of the factor. Evaluation in vivo indicated that CCN2 continued to be released at least for up to 14 days after its incorporation. Application of the gelatin hydrogel-CCN2 complex, together with a collagen scaffold to the bone defect prepared in a rat femur resulted in remarkable induction of osteoblastic mineralization markers within 2 weeks. Finally, distinct enhancement of bone regeneration was observed 3 weeks after the application of the complex. These results confirm the utility of CCN2 in the regeneration of intractable bone defects in vivo when the factor is incorporated into gelatin hydrogel.

Assessment of head wear more than ten years after total hip arthroplasty: 22-mm zirconia vs. metal heads.

The present retrospective study assessed radiographs to determine socket wear in total hip arthroplasty (THA) with 22-mm zirconia or COP (Cobalt-Chrome alloy rich in Cobalt and Phosphorous) heads, and in cemented stems at more than 10 years after operation. Sockets of ultra high molecular weight polyethylene were used in each of two THA groups (13 hips each) in a clinical trial in our hospital between 1989 and 1990. Three observers carried out masked assessments of the radiographs. Upon final examination, there was no remarkable loosening in the zirconia or COP group, and no case had required revision surgery as of 2005. There was a statistically significant difference between the 2 groups in average annual linear wear, at 0.093 mm/year and 0.046 mm/year in the zirconia and COP groups, respectively. Volume wear and average annual volume wear were also significantly greater in the zirconia group despite its superior mechanical strength and toughness in vitro. Our present findings do not confirm early expectations of lower wear in long-term results of 22-mm zirconia femoral heads used in THA.

Expression of neurotrophins and their receptors tropomyosin-related kinases (Trk) under tension-stress during distraction osteogenesis.

The localization and expression of neurotrophins and their receptors during distraction osteogenesis was investigated in 72 male rat femurs (11 weeks old) to further clarify the concurrence of cellular and molecular events of new bone formation. After osteotomy, a 7-day lag phase was followed by distraction at the rate of 0.25 mm/12 h for 21 days (distraction phase), and a 7-day consolidation phase. The localization of neurotrophins (NGF, BDNF and NT-3) and their receptors tropomyosinrelated kinases (TRKA, TRKB and TRKC) by immunostaining showed positive staining in bone forming cells in each stage, although the presence and staining intensity varied by cell type and phase. The expressions of NGF, BDNF and NT-3 by real-time polymerase chain reaction (real-time PCR) showed that the peak of the mRNA expression of NGF occurred 10 days after distraction. NT-3 increased during bone extension, but decreased when distraction stopped. In contrast, BDNF continued to increase gradually throughout the distraction and consolidation phases. These findings suggest that neurotrophins and their receptors may play different roles in endochondral and intramembranous ossification in distraction osteogenesis. The tension stress caused by distraction may stimulate the expression of neurotrophins and their receptors, and promote osteogenesis.

Lateral and posterior pillar grade changes during the treatment of Perthes disease in older patients using skin traction and range of motion exercises.

INTRODUCTION: The lateral pillar (LP) grade changes detected during treatment periods have received a lot of attention recently. Lappin et al. reported LP collapses in 92 of 275 (33%) patients during the treatment, but did not provide information for comparing treatment methods and age of onset of the disease. The purpose of this study was to review radiological changes in LP grade in older patients with Perthes disease during 20 months of treatment with skin traction and ROM exercises. We have also reported any grade changes in the posterior pillar (PP) classification. MATERIAL AND METHODS: Twenty-one patients with unilateral disease who were 9 years or older at the onset of symptoms had been followed until skeletal maturity. RESULTS: Out of 21 older patients with Perthes disease, our study had two (9.5%) who experienced LP collapse and two (9.5%) who experienced PP collapse during the first 20 months of treatment. The average time from onset to hospitalization in hips, initially classified as LP group C and PP group C, was significantly longer than in LP and PP groups A and B. The LP collapse in two hips and PP collapse in two hips occurred during months 4-8 of treatment. On the other hand, of the patients allowed to ambulate with the Pogo stick orthosis from months 8 to 12 and without a brace from months 10 to 15, none had a collapse of their LPs or PPs during these periods. CONCLUSION: Lappin et al. reported that 92 of 275 patients (33%) who were managed conservatively in several hospitals experienced LP collapse during their treatment periods. Our results suggest that older patients with this disease treated with skin traction and ROM exercises rarely suffer a LP collapse, as compared with the Lappin et al. report.

Expression of connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24 (CTGF/Hcs24/CCN2) during distraction osteogenesis.

To investigate the localization and expression of connective tissue growth factor/hypertrophic chondrocyte-specific gene product 24/CCN family member 2 (CTGF/Hcs24/CCN2) during distraction osteogenesis in the rat femur, we studied a total of 54 male rats (11 weeks old). We performed osteotomy in the midshaft of the right femur. After 7 days (lag phase), distraction was started, at the rate of 0.25 mm/12 h for 21 days (distraction phase) by using a small external fixator, and this was followed by a 7-day consolidation phase. Localization and expression of CTGF/Hcs24 during distraction osteogenesis in the femur were examined by immunostaining, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR). Immunostaining showed the localization of CTGF/Hcs24 in various cells located in the bone-forming area around the osteotomy site. During the distraction phase, in situ hybridization showed that CTGF/Hcs24 mRNA was expressed not only in hypertrophic chondrocytes and osteoblasts but also in fibroblast-like cells and mesenchymal cells at sites of end-ochondral ossification, and not only in osteoblasts but also in pre-osteoblasts and fibroblast-like cells at sites of intramembranous ossification. RT-PCR showed higher level expression of CTGF/Hcs24 mRNA in the distracted group than in the nondistracted group. These results revealed an elevated pattern of CTGF/Hcs24 mRNA expression during distraction osteogenesis, and suggest that CTGF/Hcs24 may play some roles in the endochondral and intramembranous ossification processes that occur during distraction osteogenesis.