Sex differences in reference values of hip acetabular measurements using computed tomography in Japanese adults and the effect of aging on the measurement parameters.

BACKGROUND: It is very important to understand the acetabular morphology of the normal hip joint to assist in diagnosis and surgical planning of hip disorders. The purpose of the present study was to obtain gender-based reference values for the acetabular measurements of a normal hip using computed tomography data and investigate the effect of aging on the measurement values. METHODS: We measured acetabular parameters (center-edge angle, Sharp angle, vertical center anterior angle, acetabular anteversion) on computed tomography corrected for changing the obliquity, rotation, and tilt of the pelvis. We performed measurements in 245 patients (490 joints; 120 men [240 joints] and 125 women [250 joints]). The mean age was 64.7 ± 14.3 (31-88) years for men and 63.2 ± 15.2 (30-88) years for women. RESULTS: In men and women, the mean center-edge angle was 31.8° ± 6.4° and 30.6° ± 6.5°, the mean Sharp angle was 38.6° ± 3.2° and 40.6° ± 3.8°, the mean vertical center anterior angle was 44.3° ± 7.9° and 40.0° ± 8.5°, and the mean acetabular anteversion angle was 14.3° ± 5.2° and 18.8° ± 5.4°, respectively. All differences were statistically significant. The center-edge angle increased with age in women; however, such an effect was not observed in men. The other measurements showed a similar trend, such as larger vertical center anterior angle and smaller Sharp and acetabular anteversion angles, with aging in both men and women. CONCLUSIONS: We used computed tomography data to quantitatively assess the coverage and shape of the acetabulum in adult Japanese subjects and obtain the estimated reference ranges by gender. The results also proved that the measurements changed with aging in both sexes. These facts must be taken into account during the diagnosis of hip disease and planning of surgery.

Supplying osteogenesis to dead bone using an osteogenic matrix cell sheet.

PURPOSE: To evaluate whether osteogenic matrix cell sheets can supply osteogenesis to dead bone. METHODS: Femur bone fragments (5 mm in length) were obtained from Fisher 344 rats and irradiated by a single exposure of 60 Gy to produce bones that were no longer viable. Osteogenic matrix cell sheets were created from rat bone marrow-derived stromal cells (BMSCs). After wrapping the dead bone with an osteogenic matrix cell sheet, it was subcutaneously transplanted into the back of a rat and harvested after 4 weeks. Bone formation around the dead bone was evaluated by X-ray imaging and histology. Alkaline phosphatase (ALP) and osteocalcin (OC) mRNA expression levels were measured to confirm osteogenesis of the transplanted bone. The contribution of donor cells to bone formation was assessed using the Sry gene and PKH26. RESULTS: After the cell sheet was transplanted together with dead bone, X-ray images showed abundant calcification around the dead bone. In contrast, no newly formed bone was seen in samples that were transplanted without the cell sheet. Histological sections also showed newly formed bone around dead bone in samples transplanted with the cell sheet, whereas many empty lacunae and no newly formed bone were observed in samples transplanted without the cell sheet. ALP and OC mRNA expression levels were significantly higher in dead bones transplanted with cell sheets than in those without a cell sheet (P < 0.01). Sry gene expression and cells derived from cell sheets labeled with PKH26 were detected in samples transplanted with a cell sheet, indicating survival of donor cells after transplantation. CONCLUSION: Our study indicates that osteogenic matrix cell sheet transplantation can supply osteogenesis to dead bone.

Osteogenesis of cryopreserved osteogenic matrix cell sheets.

Cryopreservation of tissue engineered bone (TEB), whilst maintaining its osteogenic ability, is imperative for large-scale clinical application. We previously reported a novel cell transplantation method, in which bone-marrow-derived mesenchymal stem cells (BMSCs) were cultured to confluence and differentiated down the osteogenic lineage to form osteogenic matrix cell sheets (OMCS). OMCS have high alkaline phosphatase (ALP) activity and osteocalcin (OC) contents and can be easily used for producing TEB. The aim of the present study was to investigate whether TEB produced by cryopreserved OMCS maintains sufficient osteogenic potential in vivo. OMCS were prepared and divided into three groups according to storage period of cryopreservation (fresh (no cryopreservation), 4 week and 12 week cryopreservation groups). OMCS were cryopreserved by storage in freezing medium (Cell Banker 1®) at -80 °C. Cryopreserved OMCSs were rapidly thawed at room temperature and wrapped around Hydroxyapatite (HA) scaffolds prior to implantation into subcutaneous sites in rats, to determine their in vivo bone-forming capability. The constructs were harvested 4 weeks after transplantation and examined histologically and biochemically. Histological analysis of the constructs showed extensive bone formation in the HA pores with high ALP activity and OC content detected in the cryopreservation groups. The present study clearly indicates that cryopreserved/thawed OMCS are still capable of producing mineralized matrix on scaffolds, resulting in bone formation. This cryopreservation technique could be applied for hard tissue reconstruction to ease the cell preparation method prior to time of use.

A pilot project for the Japan arthroplasty register.

BACKGROUND: National arthroplasty registers are valuable tools for reporting on an updated epidemiologic survey of arthroplasties and for evaluating the performance of implants and operative procedures through the early identification of failure risk factors. More than ten registers have been launched globally, but no national register has been reported in Asia. METHODS: In February 2006, a pilot project of the Japan Arthroplasty Register (JAR) for total hip arthroplasty (THA) and total knee arthroplasty/unicompartmental knee arthroplasty (TKA/UKA) was launched by the Japanese Orthopaedic Association (JOA). Data obtained include information about patients, primary and revision arthroplasty operative procedures, and implants and materials used. The JAR office accumulated and processed all data and reports annually. RESULTS: Up to May 2011, 83 of 130 hospitals nominated by the JOA (64 %) participated in the JAR pilot project. From 2006 to 2011, 33,080 data collection forms were submitted; 17,534 for THA and 17,269 for TKA/UKA. A brief summary of the annual report of the JAR is available from The Japanese Society for Replacement Arthroplasty web site at http://jsra.info/ . CONCLUSION: A national arthroplasty register is a useful tool for evaluating the outcomes of interventions and the materials used in arthroplasties and for providing rapid feedback to practitioners and patients about any failure of THA and TKA/UKA. As the first national arthroplasty register in Asia, the JAR will help guide the development of registers of arthroplasty characteristics specific to Asian populations.

Secretory osteocalcin as a nondestructive osteogenic marker of tissue-engineered bone.

BACKGROUND AND PURPOSE: The constructs of mesenchymal stem cells and ceramics form bone tissue after implantation. Therefore, the constructs can include cultured bone (tissue-engineered bone) as bone grafts. However, the selection of constructs, prior to implantation, with high osteogenic potential is still difficult. We used a rat model to measure the secretory osteocalcin level in culture medium to verify that monitoring osteocalcin levels enables the selection of constructs with high osteogenic potential. METHODS: We prepared constructs of rat hydroxyapatite/cells and used different cell passages of P-1 and P-3 as well as different cell numbers: 1 × 10(5) and 1 × 10(6) cells/ml suspension. These constructs were cultured for 14 days under osteoinductive or nonosteoinductive conditions and implanted subcutaneously in the recipient rat. Secretory osteocalcin in the culture medium was measured using an enzyme-linked immunosorbent assay system during the culture period until day 14, and the osteocalcin content of the harvested construct at 4 weeks was also measured. RESULTS AND CONCLUSION: All constructs except the hydroxyapatite/P-3 construct showed abundant bone formation by histology and both high secretory osteocalcin level in the medium and high osteocalcin content after implantation. Our study revealed that secretory osteocalcin level in vitro was related to osteocalcin content in vivo. The study clearly showed that measuring secretory osteocalcin is a nondestructive method of assessing the osteogenic potential of tissue-engineered bone. One can choose tissue-engineered bone with high osteogenic potential by integrating secretory osteocalcin measurement into the process of bone-tissue regeneration.

In vivo osteogenic capability of human mesenchymal cells cultured on hydroxyapatite and on beta-tricalcium phosphate.

The aim of the current study was to examine in vitro osteogenic capability and in vivo bone formation of mesenchymal stromal cells (MSCs) on two kinds of calcium phosphate ceramics. MSCs derived from human bone marrow were seeded on either hydroxyapatite (HA) ceramic or beta-tricalcium phosphate (beta-TCP) ceramic and then cultured in a medium supplemented with a donor's serum, vitamin C, beta-glycerophosphate, and dexamethasone. The culture revealed the expression of alkaline phosphatase activity, indicating the osteogenic differentiation of the MSCs on the ceramics (fabrication of tissue-engineered construct). The constructs were then implanted subcutaneously into nude rats for 8 weeks. New bone formation was observed in both types of ceramics, and human-specific Alu sequence was detected by in situ hybridization analysis. Quantitative microcomputed tomography showed that the volume of the new bone in the HA ceramic was greater than that in the beta-TCP ceramic in six of seven cases. These results suggest that human MSCs cultured on ceramics could retain their osteogenic capability even after ectopic implantation and provide a rationale for the use of tissue-engineered constructs derived from a patient's MSCs and calcium phosphate ceramics in bone tissue regeneration.

Differences in highly cross-linked polyethylene wear between zirconia and cobalt-chromium femoral heads in Japanese patients: a prospective, randomized study.

The purpose of this study was to compare highly cross-linked polyethylene wear between the zirconia head and the cobalt-chromium head in Japanese patients. A prospective, randomized study was performed to evaluate the outcomes in 32 hips that had zirconia heads and in 30 hips that had cobalt-chromium heads. The mean follow-up periods of both groups were same (5 years). There were no significant differences between the zirconia head and the cobalt-chromium head in the mean polyethylene linear wear per year and the mean volumetric polyethylene wear per year in the steady phase. This study indicates that zirconia head offers no benefits over metal head in terms of wear reduction at 5 years in Japanese patients who have lightweight and thin polyethylene liners.

Computed tomography-based custom-made stem for dysplastic hips in Japanese patients.

We investigated 55 hips of 53 patients with dysplastic hips. Individual computed tomography data were used in the manufacturing of cementless custom-made stems made of Ti-6Al-4V. The proximal one third was coated using porous coating covered with hydroxyapatite coating. The average age at surgery was 60 years and the average follow-up was 7 years. Five patients (9%) complained of postoperative thigh pain. According to Engh's radiologic classification system, there was bone-ingrown fixation in all hips. The cortical index and canal flare index were lower, and stem diameter was greater in the 11 hips (20%) with severe stress shielding than in the remaining 44 hips. Although the results obtained with this custom-made stem system for dysplastic hips were excellent, stress shielding is still an issue.

Inorganic antimicrobial coating for titanium alloy and its effect on bacteria.

BACKGROUND: For orthopedic implants, infection is a serious problem. Therefore, we considered an implant with antimicrobial ability can prevent infection. We tried to coat a titanium alloy surface with Novaron, a commercially available inorganic antimicrobial. The purpose of this study was to analyze the differences among the surfaces of materials coated using different processing pressures of the working gas and analysis of the antimicrobial activity. METHODS: One of the inorganic antimicrobials Novaron (grade VZ 600) was applied to titanium alloy (Ti6Al4V) plates. This antimicrobial has limited heat resistance, so we used cold spray technology to coat the titanium alloy with it. The principle of cold spray technology is spraying a powder in a high-velocity gas jet, accelerated by adiabatic expansion, against a substrate. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) were used to analyze the differences among the surfaces of materials coated using different processing pressures of the working gas. The Japanese Industrial Standard (JIS) method (JIS Z2801: 2000) was used to analyze the antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Antimicrobial activity was analyzed only for the sample coated at 3.0 MPa. RESULTS: The SEM and EDS results indicated that when the pressure of the working gas was increased, the antimicrobial coated the titanium adequately. This material showed good effects against S. aureus and P. aeruginosa and some effect for K. pneumoniae. CONCLUSIONS: Antimicrobial implants represent a preventive method against infection. There is a possibility of using them not only for clean operations but also for operations with suspected bacterial contamination, such as fixation of slight compound fractures.

Treatment of intraosseous ganglia and bone cysts of the carpal bones with injectable calcium phosphate bone cement.

This article documents the outcome of treatment of intraosseous ganglia and simple bone cysts of the carpal bones by curettage and injectable calcium phosphate bone cement (CPC) grafting. The patients consisted of five men and three women. One had a cystic lesion in the scaphoid, one in the hamate, and five in the lunate. Curettage of the lesions was performed, and CPC was injected into the cavity. Five patients were diagnosed with a ganglion and three with a simple bone cyst. Among the five patients with wrist pain, the pain disappeared completely in four. Radiographs showed apparent partial absorption of CPC in four patients and no absorption in other four. There were no recurrence of tumours and no other complications were encountered. We conclude that calcium phosphate bone cement is a useful material for repairing bone defect after curettage of an intraosseous ganglion or bone cyst of a carpal bone.

[Regenerative medicine for bone and joint].

There are the methods made various regenerative tissue from embryonic stem cell and tissue stem cell for regenerative medicine. We have performed the basic studies to product the regenerative bone and cartilage with mesenchymal stem cell included in bone marrow. Based on the results, we have cultured patient's bone marrow in cell processing center after approval of our ethic committee and placed the regenerative bone and cartilage on scaffolds and total prostheses. These materials were replaced on lesions of bone and joint diseases by cartilaginous damage, osteoarthritis, bone tumor and congenital anomaly. The follow-up periods are not so long, because they were started from 2001. The good results of them without rejection and infection have been obtained for the present.

Disease-specific expression patterns of proteases in synovial tissues.

UNLABELLED: To assess whether protease expression patterns can be discriminated according to matrix degradation mechanisms in aseptic prosthesis loosening (APL), rheumatoid arthritis (RA), and osteoarthritis (OA), we immunohistochemically examined the expressions of matrix metalloproteinase-1 and cathepsins B, D, and L in periprosthetic synovial-like interface tissues from 32 patients with failed prosthetic hips, from 29 RA-patients with hip synovial membranes, and from 35 patients with primary OA. Numerical values, calculated for the positivity of each protease, were used to rank the staining patterns, and a multivariate analysis was carried out to examine the discriminant probabilities. As a result of stepwise linear discriminant analyses, the three groups were successfully discriminated with probabilities of 100%, 62.1%, and 77.1%, respectively. Cathepsin L was significantly related to the discrimination of APL from RA and primary OA. Disease-specific protease activation pathways might exist, and cathepsin L can be a key enzyme for APL pathogenesis. LEVEL OF EVIDENCE: Prognostic study, level III (retrospective study).

Indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head.

BACKGROUND: The present study aimed to determine the indications for free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. METHODS: Seventy-one hips (60 patients) were clinically followed for a minimum of 3 years. Average follow-up period was 7 years. Etiologies were alcohol abuse in 31 hips, steroid use in 27, idiopathic in 7 and trauma in 6. Preoperative staging of the necrotic lesion was done using the Steinberg's classification system. The outcomes of free vascularized fibular grafting were determined clinically using the Harris hip-scoring system, radiographically by determining progression, and survivorship by lack of conversion to total hip replacement. RESULTS: The average preoperative Harris hip score was 56 points and the average score at the latest follow-up examination was 78 points. Forty-seven hips (67%) were clinically rated good to excellent, 4 hips (6%) were rated fair, and 20 hips (28%) were rated poor. Thirty-six hips (51%) did not show radiographic progression while 35 hips (49%) did, and with an overall survivorship of 83% at 7 years. Steroid-induced osteonecrosis was significantly associated with poor scores and survival rate (68%). Preoperative collapse was significantly associated with poor scores, radiographic progression and poor survival rate (72%). A large extent of osteonecrosis greater than 300 degrees was significantly associated with poor scores, radiographic progression and poor survival rate (67%). There was no relationship between the distance from the tip of the grafted fibula to the subchondral bone of the femoral head and postoperative radiographic progression. CONCLUSION: In conclusion, small osteonecrosis (less than 300 degrees of the femoral head) without preoperative collapse (Steinberg's stages I and II) is the major indication for free vascularized fibular grafting. Steroid-induced osteonecrosis is a relative contraindication. Large osteonecrosis (greater than 300 degrees) with severe preoperative collapse (greater than 3 mm) is a major contraindication. Hips with 2 negative factors such as severe preoperative collapse and a large extent of osteonecrosis, require hip replacements.

Modifying oxygen tension affects bone marrow stromal cell osteogenesis for regenerative medicine.

AIM: To establish a hypoxic environment for promoting osteogenesis in rat marrow stromal cells (MSCs) using osteogenic matrix cell sheets (OMCSs). METHODS: Rat MSCs were cultured in osteogenic media under one of four varying oxygen conditions: Normoxia (21% O2) for 14 d (NN), normoxia for 7 d followed by hypoxia (5% O2) for 7 d (NH), hypoxia for 7 d followed by normoxia for 7 d (HN), or hypoxia for 14 d (HH). Osteogenesis was evaluated by observing changes in cell morphology and calcium deposition, and by measuring osteocalcin secretion (ELISA) and calcium content. In vivo syngeneic transplantation using OMCSs and ß-tricalcium phosphate discs, preconditioned under NN or HN conditions, was also evaluated by histology, calcium content measurements, and real-time quantitative PCR. RESULTS: In the NN and HN groups, differentiated, cuboidal-shaped cells were readily observed, along with calcium deposits. In the HN group, the levels of secreted osteocalcin increased rapidly from day 10 as compared with the other groups, and plateaued at day 12 (P < 0.05). At day 14, the HN group showed the highest amount of calcium deposition. In vivo, the HN group showed histologically prominent new bone formation, increased calcium deposition, and higher collagen type I messenger RNA expression as compared with the NN group. CONCLUSION: The results of this study indicate that modifying oxygen tension is an effective method to enhance the osteogenic ability of MSCs used for OMCSs.

Bone regeneration with osteogenic matrix cell sheet and tricalcium phosphate: An experimental study in sheep.

AIM: To determine the effects of a cell sheet created from sheep bone marrow and tricalcium phosphate (TCP) on osteogenesis. METHODS: Bone marrow cells were harvested from a sheep and cultured in a minimal essential medium (MEM) containing ascorbic acid phosphate (AscP) and dexamethasone (Dex). After 2 wk, the formed osteogenic matrix cell sheet was lifted from the culture dish using a scraper. Additionally, harvested bone marrow cells were cultured in MEM only as a negative control group, and in MEM with AscP, Dex, and ß-glycerophosphate as a positive control group. For in vitro evaluation, we measured the alkaline phosphatase (ALP) activity and osteocalcin (OC) content in the media of the cultured cells from each group. For in vivo analysis, a porous TCP ceramic was used as a scaffold. We prepared an experimental group comprising TCP scaffolds wrapped with the osteogenic matrix cell sheets and a control group consisting of the TCP scaffold only. The constructs were implanted subcutaneously into athymic rats and the cell donor sheep, and bone formation was confirmed by histology after 4 wk. RESULTS: In the in vitro part, the mean ALP activity was 0.39 ± 0.03 mg/well in the negative control group, 0.67 ± 0.04 mg/well in the sheet group, and 0.65 ± 0.07 mg/well in the positive control group. The mean OC levels were 1.46 ± 0.33 ng/well in the negative control group, 3.92 ± 0.16 ng/well in the sheet group, and 4.4 ± 0.47 ng/well in the positive control group, respectively. The ALP activity and OC levels were significantly higher in the cell sheet and positive control groups than in the negative control group (P < 0.05). There was no significant difference in ALP activity or OC levels between the cell sheet group and the positive control group (P > 0.05). TCP constructs wrapped with cell sheets prior to implantation showed bone formation, in contrast to TCP scaffolds alone, which exhibited poor bone formation when implanted, in the subcutaneous layer both in athymic rats and in the sheep. CONCLUSION: This technique for preparing highly osteoinductive TCP may promote regeneration in large bone defects.

Early bone in-growth ability of alumina ceramic implants loaded with tissue-engineered bone.

To enhance early bonding of an alumina ceramic implant to bone, we evaluated a method of seeding the implant surface with bone marrow mesenchymal cells that differentiated to osteoblasts and bone matrix prior to implantation. The usefulness of the method was evaluated in Japanese white rabbits. In our study, an alumina ceramic test piece loaded with differentiated osteoblasts and bone matrix by a tissue engineering technique was implanted into rabbit bones. Three weeks after the procedure, evaluation of mechanical bonding and histological examination were performed. Histological examination of the noncell-loaded implant surfaces showed no bone infiltration into the implant gap. However, the cell-loaded implant surfaces exhibited new bone infiltration into the implant gap with mechanical bonding. In the mechanical test, the average failure load was 0.60 kgf for the noncell-loaded side and 1.49 kgf for the cell-loaded side. Preculturing mesenchymal cells on the surface of the alumina ceramic prior to implantation increased the debonding strength by two and half times. The present findings indicate early bonding between the implant and bone three weeks after the procedure.

Promotion of Osteogenesis and Angiogenesis in Vascularized Tissue-Engineered Bone Using Osteogenic Matrix Cell Sheets.

BACKGROUND: The regeneration of large, poorly vascularized bone defects remains a significant challenge. Although vascularized bone grafts promote osteogenesis, the required tissue harvesting causes problematic donor-site morbidity. Artificial bone substitutes are promising alternatives for regenerative medicine applications, but the incorporation of suitable cells and/or growth factors is necessary for their successful clinical application. The inclusion of vascular bundles can further enhance the bone-forming capability of bone substitutes by promoting tissue neovascularization. Little is known about how neovascularization occurs and how new bone extends within vascularized tissue-engineered bone, because no previous studies have used tissue-engineered bone to treat large, poorly vascularized defects. METHODS: In this study, the authors developed a novel vascularized tissue-engineered bone scaffold composed of osteogenic matrix cell sheets wrapped around vascular bundles within ß-tricalcium phosphate ceramics. RESULTS: Four weeks after subcutaneous transplantation in rats, making use of the femoral vascular bundle, vascularized tissue-engineered bone demonstrated more angiogenesis and higher osteogenic potential than the controls. After vascularized tissue-engineered bone implantation, abundant vascularization and new bone formation were observed radially from the vascular bundle, with increased mRNA expression of alkaline phosphatase, bone morphogenetic protein-2, osteocalcin, and vascular endothelial growth factor-A. CONCLUSION: This novel method for preparing vascularized tissue-engineered bone scaffolds may promote the regeneration of large bone defects, particularly where vascularization has been compromised.

Maxillofacial bone regeneration with osteogenic matrix cell sheets: An experimental study in rats.

OBJECTIVE: Regeneration of maxillofacial bone defects, characterized by relatively small but complicated shapes, poses a significant clinical challenge. Osteogenic matrix cell sheets (OMCSs) have osteogenic ability and good shaping properties and may be ideal graft materials. Here, we assessed whether implantation of OMCSs could be used to repair maxillofacial bone defects. DESIGN: We adopted a rat mandibular symphysis model. The rat mandible is formed by a paired bone and the central portion consisting of fibrous tissue. There is no bone tissue at the site; accordingly, this site was interpreted as a physiological bone gap and was used for evaluation. Rat bone marrow cells were cultured in medium containing dexamethasone and ascorbic acid phosphate to create OMCSs. The OMCSs were implanted into the rat mandibular symphysis without a scaffold. Microcomputed tomography and histological analyses were conducted after 2, 4, and 8 weeks. RESULTS: Two weeks after implantation, microcomputed tomography images and histological sections showed some sparse granular calcification tissue within the bone gap at the mandibular symphysis. At 4 weeks, the calcification tissue spread, and the gap of the mandibles were continued. At 8 weeks, this continuous new bone tissue was matured. The experimental group showed abundant new bone tissue in the group with OMCS implantation, but not in the group with sham implantation. CONCLUSIONS: Our present results indicated that use of OMCSs may be an optimal approach towards achieving maxillofacial regeneration.

Nontraumatic tibial polyethylene insert cone fracture in mobile-bearing posterior-stabilized total knee arthroplasty.

A 72-year-old male patient underwent mobile-bearing posterior-stabilized total knee arthroplasty for osteoarthritis. He experienced a nontraumatic polyethylene tibial insert cone fracture 27 months after surgery. Scanning electron microscopy of the fracture surface of the tibial insert cone suggested progress of ductile breaking from the posterior toward the anterior of the cone due to repeated longitudinal bending stress, leading to fatigue breaking at the anterior side of the cone, followed by the tibial insert cone fracture at the anterior side of the cone, resulting in fracture at the base of the cone. This analysis shows the risk of tibial insert cone fracture due to longitudinal stress in mobile-bearing posterior-stabilized total knee arthroplasty in which an insert is designed to highly conform to the femoral component.