Vascularized Medial Femoral Condyle Autografts for Osteochondral Lesions of the Talus: A Preliminary Prospective Randomized Controlled Trial.

Talar osteochondral lesions (OCLs) lead to progressive stages of talar destruction. Core decompression with cancellous bone grafting (CBG) is a common treatment for Berndt and Harty stages II and III. However, in a subset of patients, talar revascularization may fail. Surgical angiogenesis using vascularized medial femoral condyle (MFC) autografts may improve on these outcomes. These 2 treatment strategies were directly compared via a prospective preliminary randomized trial including 20 participants with talar core decompression followed by either cancellous (CBG group, n = 10) or vascularized MFC (MFC group, n = 10) bone grafting. Outcome analysis was performed with visual analog scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Lower Extremity Functional Scale (LEFS), and contrast-enhanced magnetic resonance imaging (MRI) scans. At 12 months of follow-up, the mean VAS score was reduced from 6.6 ± 2.5 preoperatively to 4 ± 1.9 in the CBG group and from 5.2 ± 2.9 preoperatively to 1 ± 1.1 in the MFC group (p < .001). The LEFS improved from 53.4 ± 13.1 to 62.6 ± 16.2 CBG and from 53 ± 9.3 to 72.4 ± 7.4 MFC (p = .114). AOFAS improved from 71 ± 12.1 to 84.1 ± 12.5 in CBG and from 70.5 ± 7.4 to 95.1 ± 4.8 in MFC (p = .019). The MRI scans in the CBG group demonstrated 9 partial malperfusions and 1 hypervascularized bone graft, whereas the MFC group had 8 well-vascularized grafts incorporated into the talus and 1 partial malperfusion. Vascularized MFC autografts provide superior pain relief along with improvement of physical function in patients with talar OCL stage II and III compared with CBG. To confirm these promising results, further multicenter randomized controlled trials are required.

Vascular Supply to the Femoral Head in Patients With Healed Slipped Capital Femoral Epiphysis.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is one of the most common hip disorders. The vascularity of the lateral epiphyseal vessels supplying the femoral head in patients with healed SCFE has not been well defined. The purpose of this study was to characterize the location and number of lateral epiphyseal vessels in young adults with healed SCFE. METHODS: This was a retrospective study of 17 patients (18 hips) with a diagnosis of SCFE and a matched control group of 17 patients (17 hips) with developmental dysplasia of the hip. All patients underwent high-resolution contrast-enhanced magnetic resonance imaging to visualize the path of the medial femoral circumflex artery and the lateral epiphyseal arterial branches supplying the femoral head. RESULTS: There were 5 unstable SCFEs and 13 stable SCFEs with an average slip angle of 31 degrees. (All patients had been treated with in situ pinning and screw removal). Average age at time of magnetic resonance imaging was 24.5 years (range, 15 to 34 y). The lateral epiphyseal vessels reliably inserted on the posterior-superior aspect of the femoral neck from the superior-anterior to the superior-posterior position in both the SCFE and control groups. An average of 2 (±0.8) retinacular vessels were identified in the SCFE group compared with 5.2 (±0.7) retinacular vessels in the control group (P<0.001). CONCLUSIONS: In healed SCFE, the lateral epiphyseal vessels reliably insert in the same anatomic region as patients with hip dysplasia; however, the overall number of vessels is significantly lower.

Revascularization of the necrotic femoral head after traumatic open anterior hip dislocation in a child: a case report.

INTRODUCTION: Avascular necrosis of the femoral capital epiphysis is the most serious complication after traumatic dislocation of the hip in children. This case report discusses the localization and revascularization of the necrotic femoral head following rarely experienced traumatic open anterior hip dislocation in children. CASE PRESENTATION: Our patient was an 11-year-old Japanese boy who had open anterior hip dislocation sustained in a traffic accident. Reduction of the hip joint was performed in an emergency operation, and he was evaluated using serial gadolinium-enhanced magnetic resonance imaging. T1-weighted magnetic resonance images showed two bands with low signal intensity in the femoral capital epiphysis on coronal and oblique axial planes, indicating the existence of avascular osteonecrosis of the femoral head. We observed gadolinium enhancement in the central region of the epiphysis, where the area between the two bands with low signal intensity was located. Serial assessment with enhanced magnetic resonance images during a non-weight-bearing period of 1.5 years after injury showed revascularization starting from the central region and converging toward the peripheral region. Although the patient had leg-length discrepancy due to the early epiphyseal closure, non-weight-bearing treatment for the avascular osteonecrosis of the femoral head achieved a favorable outcome without any hip joint dysfunction, pain, or sign of secondary osteoarthritic change within 4.5 years after injury. CONCLUSION: We confirmed the revascularization process of the necrotic lesion in the femoral capital epiphysis in an 11-year-old boy using serial gadolinium-enhanced magnetic resonance imaging. Conservative non-weight-bearing treatment achieved a favorable outcome.

Vascularized Fibula Epiphysis Transfer for Pediatric Extremity Reconstruction: A Systematic Review and Meta-analysis.

BACKGROUND: Vascularized fibula epiphysis transfer for pediatric extremity reconstruction intends to preserve growth potential. However, few cases are reported, and outcomes are poorly characterized. METHODS: Systematic review was performed through a MEDLINE search using keywords "pediatric" or "epiphyseal" and "vascularized fibula." Patients were divided into upper extremity or lower extremity groups. Functional and growth outcomes were assessed, and indications, pedicle, complications, and need for secondary surgery were recorded. RESULTS: Twenty publications with 62 patients were included. Mean age was 5.9 years, and mean follow-up was 5.8 years. Indications included sarcoma (60%), congenital deformity (21%), trauma (13%), and infection (6%). Anterior tibial pedicle was most common (63%) and was associated with significantly improved growth outcomes compared with the peroneal pedicle (23%; P < 0.001). Fifty-three patients underwent upper extremity reconstruction, with the most common complication being fracture (35%) and most common secondary surgery flap salvage (7%). Among upper extremity patients, full function was achieved in 25% and impaired function in 75%. Full growth was observed in 63% of patients, partial growth in 31%, and no growth in 4%. Nine patients underwent lower extremity reconstruction, with the most common complication being fracture (22%) and most common secondary surgery derotational osteotomy (22%). Among lower extremity patients, full function was achieved in 44% and impaired function in 56%. Full growth was observed in 56% of patients, partial growth in 22%, and no growth in 22%. CONCLUSIONS: Vascularized fibula epiphysis transfer can accomplish full long-term growth and function. However, complications, revision surgery, and chronic impairment are common.

A simple, precocious, and reliable way to assess future clinical outcome in children with Perthes disease and mild femoral head involvement: correlation between MRI with diffusion-weighted and dynamic gadolinium-enhanced subtraction and Catterall and Herring classifications.

BACKGROUND: In children older than 5 years with a mild form of Legg-Calvé-Perthes disease, the outcome is difficult to predict. In this study, we retrospectively correlated gadolinium-enhanced subtracted (DGS) and diffusion (DWI) MRI findings to the radiographic assessment according to the Catterall and Herring et al. classifications and to the final score according to Stulberg et al.: the aim was to identify a precocious, simple, and objective criterion to differentiate between forms evolving favourably and forms requiring an early surgical treatment in order to avoid femoral head deformity and subsequent osteoarthritis. METHODS: Twelve boys with unilateral mild femoral head involvement (Catterall grade 2 or grade 3) underwent DSG and DWI MR during the early phase of the disease. The absence of enhancement of the external pillar on DSG MRI and the presence of metaphyseal hyperintensity on DWI were considered to be the signs of poor outcome. These findings were correlated with the Catterall and Herring et al. classifications at the initial sclerotic stage and early fragmentation phase and with the Stulberg et al. classifications at least 5 years after the onset of the disease. RESULTS: DSG MRI findings correctly discriminated three out of four patients with a good outcome but underestimated two out of eight patients with a poor outcome. DWI findings correlated with the Catterall and Herring et al. classifications in 12 out of 12 cases. In only one case, DWI findings did not correlate with the Stulberg et al. classification. CONCLUSION: DWI MR provides an objective and accurate prognostic criterion that is relatively easy to recognise. DGS MR findings are less accurate, thus underestimating the gravity of the disease in one-fourth of the patients with a poor outcome.

Restoration of Blood Flow to the Proximal Femoral Epiphysis in Unstable Slipped Capital Femoral Epiphysis by Modified Dunn Procedure: A Preliminary Angiographic and Intracranial Pressure Monitoring Study.

BACKGROUND: The major complication of unstable slipped capital femoral epiphysis (SCFE) is avascular necrosis (AVN) of the femoral head. The purpose of this study was to document by angiography the preoperative and postoperative perfusion to the proximal femoral epiphysis following an unstable SCFE. A specific aim was to determine whether blood flow could be restored. A secondary aim was to determine the efficacy of an intracranial pressure (ICP) monitor to assess blood flow within the femoral head intraoperatively. METHODS: Nine patients with an unstable SCFE underwent superselective angiogram of the medial circumflex femoral artery preoperatively, followed by operative fixation with an open reduction using a modified Dunn approach. Femoral head blood flow was evaluated with an ICP monitor. Angiography was repeated postoperatively. Patients were followed radiographically to assess for AVN. RESULTS: Follow-up averaged 22 months. Six patients did not have arterial flow to the femoral head on the preoperative angiogram. Flow was restored postoperatively on angiogram in 4 of the 6 patients. Two patients developed AVN. One had no flow to the femoral head preoperatively or postoperatively on angiogram and complete tearing of the periosteum was noted. In 1 patient, there was no ICP waveform after the initial reduction. After removing more callous and repeating reduction, the waveform returned. Of the 2 patients with AVN, 1 had an ICP waveform after reduction. CONCLUSIONS: This study documents that some patients with unstable SCFE present with reduced femoral head blood supply due to SCFE. It also demonstrates blood flow restoration in 4 patients by angiogram and 5 by ICP monitor after surgical treatment. No patient immediately lost blood flow due to surgery. ICP monitor is a safe intraoperative tool for real-time assessment of femoral head blood flow during open reduction of unstable SCFE. Presence of flow by ICP is not a guarantee that AVN will not develop, but absence of flow was predictive of AVN. LEVEL OF EVIDENCE: Therapeutic level I-prognostic. See Instructions for Authors for a complete description of levels of evidence.

Increased diffusion and decreased perfusion in epiphyses of femoral heads detected via intravoxel incoherent motion after closed reduction in children with developmental dysplasia of the hip.

Background Patients with developmental dysplasia of the hip (DDH) may have decreased blood supply to the femoral heads. Finding a non-invasive method to evaluate whether the femoral heads in patients with DDH are ischemic is paramount for orthopedic surgeons. Purpose To identify whether parameters reflecting perfusion and diffusion in intravoxel incoherent motion (IVIM) sequences can be used to assess ischemia in femoral heads in patients with DDH after closed reduction. Material and Methods Twenty-eight patients with DDH who had undergone closed reduction were enrolled. IVIM data were acquired using a 3-T magnetic resonance scanner, regions of interest were placed on the epiphyses; ADCslow, ADCfast, f, and ADCfast×f were measured. A Mann-Whitney U test was performed to compare ADCslow, ADCfast, f, and ADCfast×f between the lesion and control sides. Receiver operating characteristic curves were generated with respective cut-off values. The lesion sides were classified based on the International Hip Dysplasia Institute (IHDI) classification. ADCslow, ADCfast, f, and ADCfast×f were compared among the groups. Results ADCslow was higher and ADCfast, f, and ADCfast×f were lower on the lesion sides ( P = 0.000-0.002). The optimal cut-off value for ADCfast×f, ADCfast, ADCslow, and f were 0.030, 0.626, 0.000251, and 0.636, respectively. Higher IHDI classification scores on the lesion side were associated with lower ADCfast, f, and ADCfast×f, and higher ADCslow values. Conclusion IVIM is a promising method to investigate the perfusion and diffusion of epiphyses of femoral heads.

Epiphyseal Arterial Network and Inferior Retinacular Artery Seem Critical to Femoral Head Perfusion in Adults With Femoral Neck Fractures.

BACKGROUND: A better understanding of the blood supply of the femoral head is essential to guide therapeutic strategies for patients with femoral neck fractures. However, because of the limitations of conventional techniques, the precise distribution and characteristics of intraosseous arteries of the femoral head are not well displayed. QUESTIONS/PURPOSES: To explore the characteristics and interconnections of the intraosseous vessel system between different areas of the femoral head and the possible blood supply compensatory mechanism after femoral neck fracture. METHODS: The three-dimensional (3-D) structures of the intraosseous blood supply in 30 uninjured normal human femoral heads were reconstructed using angiography methods and microCT scans. The data were imported in the AMIRA® and MIMICS® software programs to reconstruct and quantify the extra- and intraosseous arteries (diameter, length). In a separate experiment, we evaluated the residual blood supply of femoral heads in 27 patients with femoral neck fractures before surgery by analyzing digital subtraction angiography data; during the study period, this was performed on all patients in whom hip-preserving surgery was planned, rather than arthroplasty. The number of affected and unaffected subjects included in the three groups (superior, inferior, and anterior retinacular arteries) with different types of fractures (Garden Types I-IV) were recorded and analyzed (Fisher's exact test) to reflect the affected degrees of these three groups of retinacular arteries in patients after femoral neck fractures. RESULTS: The main results of our cadaver study were: (1) the main blood supply sources of the femoral head were connected by three main network structures as a whole, and the epiphyseal arterial network is the most widely distributed and the primary network structure in the femoral head; (2) the main stems of the epiphyseal arteries which were located on the periphery of the intraosseous vascular system have fewer anastomoses than the network located in the central region; (3) compared with the round ligament artery and anterior retinacular artery, the inferior retinacular artery has a relatively large caliber. Digital subtraction angiography of the 27 patients with hip fractures indicated that the inferior retinacular arterial system had a high likelihood of being unaffected after femoral neck fracture (100% [14 of 14] in nondisplaced fractures and 60% [six of 10] in Garden Type III fractures). CONCLUSIONS: The epiphyseal arterial network and inferior retinacular arterial system appear to be two important structures for maintaining the femoral head blood supply after femoral neck fracture. Increased efforts to protect these key structures during surgery, such as drilling and placing internal implants closer to the central region of the femoral head, might be helpful to reduce the effect of iatrogenic injury of the intraosseous vascular system. CLINICAL RELEVANCE: 3-D anatomic evidence of intraosseous arterial distribution of the femoral head and the high frequency with which the inferior retinacular arteries remained patent after femoral neck fracture lead us to consider the necessity of drilling and placing internal implants closer to the central region of the femoral head during surgery. Future controlled studies might evaluate this proposition.

Skeletal immaturity, rostral sparing, and disparate hip morphologies as biomechanical causes for Legg-Calvé-Perthes' disease.

Legg-Calvé-Perthes' (Perthes') disease is a developmental disease of the hip joint that may result in numerous short and long term problems. The etiology of the disease remains largely unknown, but the mechanism is believed to be vascular and/or biomechanical in nature. There are several anatomical characteristics that tend to be prevalent in children with Perthes' disease, namely: skeletal immaturity, reduced height, and rostral sparing. We present an overview of the literature, summarizing the current understanding of the pathogenesis, particularly related to how the formation of the vasculature to the femoral epiphysis places children aged 5-8 at a higher risk for Perthes' disease, how skeletal immaturity and rostral sparing could increase the probability of developing Perthes' disease, and how animal models have aided our understanding of the disease. In doing so, we also explore why Perthes' disease is correlated to latitude, with populations at higher latitudes having higher incidence rates than populations closer to the Equator. Finally, we present five hypotheses detailing how Perthes' disease could have a biomechanical cause. Clin. Anat. 29:759-772, 2016. © 2016 Wiley Periodicals, Inc.

Vascularized proximal fibula epiphyseal transfer for distal radius reconstruction in children: A systematic review.

PURPOSE: Reconstruction of the distal radius in children is cumbersome, requiring simultaneous restoration of joint function and axial growth. Vascularized proximal fibular epiphyseal transfers (VFET) have been popularized over non-vascularized transfers and prosthesis. This systematic review aims to evaluate the effectiveness of VFET and its associated complications. METHODS: Electronic database of PubMed MEDLINE was searched between 1970 and 2014. Studies reporting VFET for distal radius reconstruction in children (<15 years old) with clear reporting of technique (vascular pedicle) and objective outcome measures were included. Outcomes of interest were rate of graft growth, bone union and complications. A one-way Analysis of Variance (ANOVA) test was used to compare growth rates between pedicle types. RESULTS: Fourteen studies met the inclusion criteria, representing 25 patients. Pedicles used were anterior tibial (44%), peroneal (16%), or bi-pedicled (40%) anastomosed in antegrade (64%) or reverse flow (36%) fashion. Among all pedicle types, best results were achieved using anterior tibial artery with reversed flow, yielding average growth rate of 0.83 cm/year (P = 0.01). Recipient complications included four premature epiphyseal plate closures, a flap loss, and six wrist radial deviations. Donor complications included six common peroneal nerve palsies (five temporary, a permanent), and a talocalcaneal instability. Overall complication rates between pedicle types were comparable (P = 0.062). CONCLUSION: VFET may be a surgical option capable of restoring joint function and axial growth potential in select patients. The reverse flow technique based on the anterior tibial artery may result in superior outcomes. However, the overall complication rate is high and permanent peroneal nerve palsy may result. LEVEL OF EVIDENCE: IV © 2015 Wiley Periodicals, Inc. Microsurgery 36:705-711, 2016.

Lateral Femoral Condyle Flap: An Alternative Source of Vascularized Bone From the Distal Femur.

PURPOSE: To elucidate the vascular anatomy of the superolateral geniculate artery (SLGA) and its supply to the periosteum of the lateral femoral condyle (LFC) and to provide guidelines for flap design and describe an illustrative case. METHODS: Thirty-one fresh cadaveric limbs were dissected. The vascular anatomy of the SLGA and its distal branches to skin, muscle, and periosteum were identified. Fluoroscopic images were taken during continuous perfusion of a radiopaque contrast dye into the SLGA. Intra-arterial injections of latex rubber were performed in 12 cadaver limbs. The vascular territory was traced from the SLGA to its distal branches, and surrounding soft tissues were dissected. RESULTS: The SLGA originated from the popliteal artery 4.9 ± 1.2 cm (range, 2.8-7 cm) from the knee joint and its pedicle diameter was 1.8 ± 0.5 mm (range, 1-3 mm). SGLA pedicle-specific fluoroscopic angiography demonstrated a dense filigree of vessels over the lateral distal femur. Arterial latex injections confirmed that the SLGA supplied the periosteum of the LFC and distal femur shaft. The proximal-most extent of periosteal perfusion was 11.7 ± 2.1 cm (range, 9.3-14.1 cm) from the knee joint. The average pedicle length of LFC osteoperiosteal flaps was 4.8 ± 0.9 cm (range, 3.5-6.3 cm). CONCLUSIONS: The LFC flap consistently demonstrated almost 12 cm of femur length perfusion based on the SLGA pedicle. The anatomy of this flap enables chimeric designs combining soft tissue, bone, and cartilage. CLINICAL RELEVANCE: The vascularized LFC flap is an option for reconstruction of osseous defects of the upper extremity.

Ischemic necrosis of the femoral head: an experimental rabbit model.

To describe the morphology of the proximal femoral epiphysis in a rabbit model from the ischemic insult to the end of the revascularization process. Ischemia of the femoral head was induced in 32 rabbits at the 8th day of life, by sectioning the joint capsule and the ligamentum teres and dislocating the femoral head. Rabbits were sacrificed at 4, 8, 12, 18, 21, 26, 34, and 48 days after surgery and femoral heads were observed histologically. During the first days following the ischemic injury, large areas underwent necrotic changes. Both epiphyseal and physeal cartilage were thicker than normal and less trabecular bone formation was evident. Bone marrow was also diffusely necrotic within the secondary center of ossification. After day 12th, reparative process started with formation of extensive areas of fibrocartilage and several secondary centers of ossifications. At that stage femoral head deformity was already evident. In the following days the secondary centers of ossification cohalesced and epiphyseal and physeal cartilage resumed a normal appearance, but the femur showed a permanent deformity. In newborn rabbits, the ischemic injury to the femoral head blocked the ossification of the epiphyseal and physeal cartilage associated to necrotic bone marrow within the secondary center of ossification of the femoral head as well as to extensive areas of necrosis of epiphyseal and physeal cartilage. Extensive areas of fibrocartilage and small newly formed ossification centers within the femoral epiphysis were the results of the revascularization process, and femoral head deformity became stable afterward.

Slipped capital femoral epiphysis: how to evaluate with a review and update of treatment.

Slipped capital femoral epiphysis (SCFE) involves displacement of the proximal femoral metaphysis relative to a fixed epiphysis, usually during a period of rapid growth and unique physeal susceptibility. Patients have characteristic clinical, histologic, and radiologic features. Several clinical signs and medical diagnoses should prompt radiologic and laboratory workup. Limp or hip or knee pain in a patient 10 to 16 years old should include SCFE in the differential. If confirmed, appropriate treatment involves proximal femoral physeal stabilization and/or realignment. The optimal surgical treatment of severe SCFE and its late sequela remain an evolving and controversial subject.

Palmitoyl acyltransferase, Zdhhc13, facilitates bone mass acquisition by regulating postnatal epiphyseal development and endochondral ossification: a mouse model.

ZDHHC13 is a member of DHHC-containing palmitoyl acyltransferases (PATs) family of enzymes. It functions by post-translationally adding 16-carbon palmitate to proteins through a thioester linkage. We have previously shown that mice carrying a recessive Zdhhc13 nonsense mutation causing a Zdhcc13 deficiency develop alopecia, amyloidosis and osteoporosis. Our goal was to investigate the pathogenic mechanism of osteoporosis in the context of this mutation in mice. Body size, skeletal structure and trabecular bone were similar in Zdhhc13 WT and mutant mice at birth. Growth retardation and delayed secondary ossification center formation were first observed at day 10 and at 4 weeks of age, disorganization in growth plate structure and osteoporosis became evident in mutant mice. Serial microCT from 4-20 week-olds revealed that Zdhhc13 mutant mice had reduced bone mineral density. Through co-immunoprecipitation and acyl-biotin exchange, MT1-MMP was identified as a direct substrate of ZDHHC13. In cells, reduction of MT1-MMP palmitoylation affected its subcellular distribution and was associated with decreased VEGF and osteocalcin expression in chondrocytes and osteoblasts. In Zdhhc13 mutant mice epiphysis where MT1-MMP was under palmitoylated, VEGF in hypertrophic chondrocytes and osteocalcin at the cartilage-bone interface were reduced based on immunohistochemical analyses. Our results suggest that Zdhhc13 is a novel regulator of postnatal skeletal development and bone mass acquisition. To our knowledge, these are the first data to suggest that ZDHHC13-mediated MT1-MMP palmitoylation is a key modulator of bone homeostasis. These data may provide novel insights into the role of palmitoylation in the pathogenesis of human osteoporosis.

Primary epiphyseal arteriopathy in a mouse model of steroid-induced osteonecrosis.

Patients undergoing glucocorticoid therapy for a variety of disorders, including autoimmune diseases and hematological malignancies, are at risk of developing osteonecrosis. Despite extensive research in both patients and animal models, the underlying pathogenesis remains unclear. Proposed inciting mechanisms include intravascular thrombotic occlusion, marrow fat hypertrophy, osteocyte and/or endothelial cell apoptosis, hypercoagulability, and vasoconstriction of specific arteries and arterioles supplying bone. Our laboratory has developed a model of steroid-induced osteonecrosis in BALBcJ mice which reflects clinically relevant exposures to glucocorticoids in which treated mice develop osteonecrosis of the distal femoral epiphysis when administered 4 to 8 mg/L dexamethasone in drinking water for 6 weeks. We identified lesions in arterioles supplying this area, with the mildest occurring in knees without any evidence of osteonecrosis. However, arteriopathy was more common among mice that did versus did not develop osteonecrosis (P < 0.0001); in mice with osteonecrosis, the associated vessels showed transmural necrosis and thickening of the vessel wall progressing to the point of luminal obstruction. In the most severe cases of osteonecrosis, end-stage lesions consisted of fully occluded vessels with marrow and bone necrosis involving the entire epiphysis. We propose that a primary arteriopathy is the initiating event in the genesis of steroid-induced osteonecrosis and provides a basis for future investigation of this disease process.

Does dynamic immobilization reduce chondrocyte apoptosis and disturbance to the femoral head perfusion?

The purpose of this study is to investigate whether the dynamic hip immobilization is more favourable for lessening ischemic injury to the immature femoral head than a static immobilization. 152 Japanese white rabbits were divided into four groups randomly, and the hips were immobilized into "human" position (group A), "frog leg" position (group B) and "dynamic frog leg" position (group C). Group D was used as control. Ten rabbits in each group were killed, and the hip specimens were harvested at 1, 2, and 3 weeks after immobilization. Bcl-2/Bax expression balance and chondrocytes apoptosis were analyzed. The remaining eight rabbits in each group were used to measure the blood supply of capital femoral epiphysis by selective vascular perfusion with Indian ink. The Bcl-2/Bax expression ratio in group C was significantly increased than that in group A and B (p<0.001), while that was not significantly different from control group (p=0.0592). At three weeks after immobilization, the average apoptotic ratio was 36.7%, 45.8%, and 26.7% in group A, B and C, respectively (p<0.01). There was no significant difference between group C and normal control (p=0.0597). The perfusion ratio was 0.03±0.03, 0.03±0.02, and 0.08±0.03 in group A, B and C respectively, and 0.12±0.04 in control group (p<0.05). Thus, the dynamic immobilization model exhibited a relatively less chondrocytes apoptosis and disturbance to the femoral head perfusion than other immobilizations in vivo, which therefore may be useful for reducing avascular necrosis following the treatment of developmental dysplasia of the hip.

Growth potential of different zones of the growth plate-an experimental study in rabbits.

Despite clinical efforts to treat growth disturbances only little is known about the growth potential of the different zones of the growth plate. The aim of this study was to investigate the growth potential of different zones of the growth plate. A total of 20 New Zealand White rabbits were used for this experiment. The right and left ulna of each animal were used resulting in a total of 40 ulnae. Animals were assigned into five groups. In groups I and II resection of the metaphyseal (n = 12) or the epiphyseal (n = 6) segment of the growth plate was performed. In group III resection of the growth plate and re-implantation was performed (n = 6). In group IV the growth plate was resected and re-implanted after a 180° rotation (n = 6). Animals in group V served as controls. Histologic and radiologic examinations were performed to evaluate the growth process at 1, 2, 4, and 12 weeks following surgery. In group I, III, and IV temporary growth disturbance which was compensated within a short time was observed. Resection of the epiphyseal part resulted in growth arrest of the distal ulna in combination with normal growth of the radius which led to and valgus deformity of the limb. The results of this study indicate the importance of the reserve zone for the functioning of the growth plate.

Difference in intraosseous blood vessel volume and number in osteoporotic model mice induced by spinal cord injury and sciatic nerve resection.

In the present study, we examined intraosseous blood vessel parameters of the tibial metaphysis in mice using microcomputed tomography (µCT) to investigate the relationship between post-nerve-injury osteoporosis and local intraosseous blood vessel volume and number. Mice were randomly divided into groups receiving spinal cord injury (SCI), sciatic nerve resection group (NX), or intact controls (30 mice/group). Four weeks after surgery, mice were perfused with silicone and the distribution of intraosseous blood vessels analyzed by µCT. The bone density, µCT microstructure, biomechanical properties, and the immunohistochemical and biochemical indicators of angiogenesis were also measured. The SCI group showed significantly reduced tibial metaphysis bone density, µCT bone microstructure, tibial biomechanical properties, indicators of angiogenesis, and intraosseous blood vessel parameters compared to the NX group. Furthermore, the spinal cord-injured mice exhibited significantly decreased intraosseous blood vessel volume and number during the development of osteoporosis. In conclusion, these data suggest that decreased intraosseous blood vessel volume and number may play an important role in the development of post-nerve-injury osteoporosis.

Adolescent slipped capital femoral epiphysis treated by a modified Dunn osteotomy with surgical hip dislocation.

Between June 2001 and November 2008 a modified Dunn osteotomy with a surgical hip dislocation was performed in 30 hips in 28 patients with slipped capital femoral epiphysis. Complications and clinical and radiological outcomes after a mean follow-up of 3.8 years (1.0 to 8.5) were documented. Subjective outcome was assessed using the Harris hip score and the Western Ontario and McMaster Universities osteoarthritis index questionnaire. Anatomical or near-anatomical reduction was achieved in all cases. The epiphysis in one hip showed no perfusion intra-operatively and developed avascular necrosis. There was an excellent outcome in 28 hips. Failure of the implants with a need for revision surgery occurred in four hips. Anatomical reduction can be achieved by this technique, with a low risk of avascular necrosis. Cautious follow-up is necessary in order to avoid implant failure.