Fracture incidence and fracture-related mortality decreased with decreases in population mobility during the early days of the COVID-19 pandemic: an epidemiological study.

INTRODUCTION: We investigated the impact of coronavirus disease 2019 (COVID-19) social distancing measures on fracture incidence and fracture-related mortality, as well as associations with population mobility. METHODS: In total, 47 186 fractures were analysed across 43 public hospitals from 22 November 2016 to 26 March 2020. Considering the smartphone penetration of 91.5% in the study population, population mobility was quantified using Apple Inc's Mobility Trends Report, an index of internet location services usage volume. Fracture incidences were compared between the first 62 days of social distancing measures and corresponding preceding epochs. Primary outcomes were associations between fracture incidence and population mobility, quantified by incidence rate ratios (IRRs). Secondary outcomes included fracture-related mortality rate (death within 30 days of fracture) and associations between emergency orthopaedic healthcare demand and population mobility. RESULTS: Overall, 1748 fewer fractures than projected were observed during the first 62 days of COVID-19 social distancing (fracture incidence: 321.9 vs 459.1 per 100 000 person-years, P<0.001); the relative risk was 0.690, compared with mean incidences during the same period in the previous 3 years. Population mobility exhibited significant associations with fracture incidence (IRR=1.0055, P<0.001), fracture-related emergency department attendances (IRR=1.0076, P<0.001), hospital admissions (IRR=1.0054, P<0.001), and subsequent surgery (IRR=1.0041, P<0.001). Fracture-related mortality decreased from 4.70 (in prior years) to 3.22 deaths per 100 000 person-years during the COVID-19 social distancing period (P<0.001). CONCLUSION: Fracture incidence and fracture-related mortality decreased during the early days of the COVID-19 pandemic; they demonstrated significant temporal associations with daily population mobility, presumably as a collateral effect of social distancing measures.

Tuberculosis of the spine with severe angular kyphosis: mean 34-year post-operative follow-up shows that prevention is better than salvage.

AIMS: To address the natural history of severe post-tuberculous (TB) kyphosis, with focus upon the long-term neurological outcome, occurrence of restrictive lung disease, and the effect on life expectancy. PATIENTS AND METHODS: This is a retrospective clinical review of prospectively collected imaging data based at a single institute. A total of 24 patients of Southern Chinese origin who presented with spinal TB with a mean of 113° of kyphosis (65° to 159°) who fulfilled inclusion criteria were reviewed. Plain radiographs were used to assess the degree of spinal deformity. Myelography, CT and MRI were used when available to assess the integrity of the spinal cord and canal. Patient demographics, age of onset of spinal TB and interventions, types of surgical procedure, intra- and post-operative complications, and neurological status were assessed. RESULTS: All except one of the 24 patients were treated with anti-TB chemotherapy when they were first diagnosed with spinal TB. They subsequently received surgery either for neurological deterioration, or deformity correction in later life. The mean follow-up was 34 years (11 to 59) since these surgical interventions. Some 16 patients (66.7%) suffered from late neurological deterioration at a mean of 26 years (8 to 49) after the initial drug treatment. The causes of neurological deterioration were healed disease in nine patients (56.2%), re-activation in six patients (37.5%) and adjacent level spinal stenosis in one patient (6.3%). The result of surgery was worse in healed disease. Eight patients without neurological deterioration received surgery to correct the kyphosis. The mean correction ranged from 97° to 72°. Three patients who were clinically quiescent with no neurological deterioration were found to have active TB of the spine. Solid fusion was achieved in all cases and no patient suffered from neurological deterioration after 42 years of follow-up. On final follow-up, six patients were noted to have deceased (age range: 47 years to 75 years). CONCLUSION: Our study presents one of the longest assessments of spinal TB with severe kyphosis. Severe post-TB kyphosis may lead to significant health problems many years following the initial drug treatment. Early surgical correction of the kyphosis, solid fusion and regular surveillance may avoid late complications. Paraplegia, restrictive lung disease and early onset kyphosis might relate to early death. Clinically quiescent disease does not mean cure. Cite this article: Bone Joint J 2017;99-B:1381-8.

The use of the distal radius and ulna classification for the prediction of growth: peak growth spurt and growth cessation.

AIMS: We report the use of the distal radius and ulna (DRU) classification for the prediction of peak growth (PG) and growth cessation (GC) in 777 patients with idiopathic scoliosis. We compare this classification with other commonly used parameters of maturity. PATIENTS AND METHODS: The following data were extracted from the patients' records and radiographs: chronological age, body height (BH), arm span (AS), date of menarche, Risser sign, DRU grade and status of the phalangeal and metacarpal physes. The mean rates of growth were recorded according to each parameter of maturity. PG was defined as the summit of the curve and GC as the plateau in deceleration of growth. The rates of growth at PG and GC were used for analysis using receiver operating characteristic (ROC) curves to determine the strength and cutoff values of the parameters of growth. RESULTS: The most specific grades for PG using the DRU classification were radial grade 6 and ulnar grade 5, and for GC were radial grade 9 and ulnar grade 7. The DRU classification spanned both PG and GC, enabling better prediction of these clinically relevant stages than other methods. The rate of PG (≥ 0.7 cm/month) and GC (≤ 0.15 cm/month) was the same for girls and boys, in BH and AS measurements. CONCLUSION: This is the first study to note that the DRU classification can predict both PG and GC, providing evidence that it may aid the management of patients with idiopathic scoliosis. Cite this article: Bone Joint J 2016;98-B:1689-96.

Classification of Schmorl's nodes of the lumbar spine and association with disc degeneration: a large-scale population-based MRI study.

OBJECTIVE: Schmorl's nodes (SN) are highly associated with lumbar disc degeneration (DD). However, SN present with different morphologies/topographies that may be associated with varying degrees of DD. This study proposed a classification of SN to determine their morphological/topographical prevalence and association with the severity of DD. METHODS: Sagittal T2-weighted MRIs were assessed to identify SN and additional imaging findings from L1-S1 in 2,449 individuals. SN characteristics were classified by six criteria: disc level; endplate involvement; shape; size; location of endplate zone; and the presence of marrow changes. Hierarchical clustering was performed to identify distinct SN characteristics with endplate patterns. RESULTS: Good to excellent observer classification reliability was noted. SN most commonly presented at the L1 and L2 disc levels, and entailed one-third of the endplate, predominantly the middle zone. Round shape (39.2%) was the most common SN shape. Four specific SN and endplate linkage patterns were identified. 8.3% of identified SN (n = 960) were "Atypical SN". Multivariable regression showed that "Typical SN" and "Atypical SN", depending on levels, were associated with an adjusted 2- to 4-fold and a 5- to 13-fold higher risk of increased severity of DD, respectively (p < 0.05). CONCLUSIONS: This is the first large-scale magnetic resonance imaging (MRI) study to propose a novel SN classification. Specific SN-types were identified, which were associated with more severe DD. This study further broadens our understanding of the role of SN and degrees of DD, further expanding on the SN phenotyping that can be internationally adopted for utility assessment.

Matrix metalloproteinase 12 is an indicator of intervertebral disc degeneration co-expressed with fibrotic markers.

OBJECTIVE: Recent evidence suggests a role of fibrogenesis in intervertebral disc (IVD) degeneration. We aim to explore if fibrotic genes may serve as IVD degeneration indicators, and if their expression is associated with myofibroblast activity. DESIGN: Transcriptional expression of fibrosis markers (COL1A1, COL3A1, FN1, HSP47, MMP12, RASAL1) were analyzed in degenerated (D) and non-degenerated (ND) human nucleus pulposus (NP) and annulus fibrosus (AF) cells, along with traditional (SOX9, ACAN) and newly established degeneration markers (CDH2, KRT19, KRT18, FBLN1, MGP, and COMP). Protein expression was investigated by immunohistochemistry in human IVDs, and in rodent IVDs undergoing natural ageing or puncture-induced degeneration. Co-expression with myofibroblast markers was examined by double staining on human and rat specimens. Disc degeneration severity and extent of fibrosis were determined by histological scoring and picrosirius red staining respectively. RESULTS: Human D-NP showed more intensive staining for picrosirius red than ND-NP. Among the genes examined, D-NP showed significantly higher MMP12 expression along with lower KRT19 expression. Protein expression analysis revealed increased MMP12(+) cells in human D-IVD. Histological scoring indicated mild degeneration in the punctured rat discs and discs of ageing mouse. Higher MMP12 positivity was found in peripheral NP and AF of the degenerative rat discs and in NP of the aged mice. In addition, human D-NP and D-AF showed increased α-SMA(+) cells, indicating enhanced myofibroblast activity. MMP12 was found co-expressed with α-SMA, FSP1 and FAP-α in human and rat degenerative IVDs. CONCLUSIONS: Our study suggests that in addition to a reduced KRT19 expression, an increased expression of MMP12, a profibrotic mediator, is characteristic of disc degenerative changes. Co-expression study indicates an association of the increased MMP12 positivity with myofibroblast activity in degenerated IVDs. Overall, our findings implicate an impact of MMP12 in disc cell homeostasis. The precise role of MMP12 in IVD degeneration warrants further investigation.

Fibrotic-like changes in degenerate human intervertebral discs revealed by quantitative proteomic analysis.

OBJECTIVE: Intervertebral disc degeneration (IDD) can lead to symptomatic conditions including sciatica and back pain. The purpose of this study is to understand the extracellular matrix (ECM) changes in disc biology through comparative proteomic analysis of degenerated and non-degenerated human intervertebral disc (IVD) tissues of different ages. DESIGN: Seven non-degenerated (11-46 years of age) and seven degenerated (16-53 years of age) annulus fibrosus (AF) and nucleus pulposus (NP) samples were used. Proteins were extracted using guanidine hydrochloride, separated from large proteoglycans (PGs) by caesium chloride (CsCl) density gradient ultracentrifugation, and identified using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). For quantitative comparison, proteins were labeled with iTRAQ reagents. Collagen fibrils in the NP were assessed using scanning electron microscopy (SEM). RESULTS: In the AF, quantitative analysis revealed increased levels of HTRA1, COMP and CILP in degeneration when compared with samples from older individuals. Fibronectin showed increment with age and degeneration. In the NP, more CILP and CILP2 were present in degenerated samples of younger individuals. Reduced protein solubility was observed in degenerated and older non-degenerated samples correlated with an accumulation of type I collagen in the insoluble fibers. Characterization of collagen fibrils in the NP revealed smaller mean fibril diameters and decreased porosity in the degenerated samples. CONCLUSIONS: Our study identified distinct matrix changes associated with aging and degeneration in the intervertebral discs (IVDs). The nature of the ECM changes, together with observed decreased in solubility and changes in fibril diameter is consistent with a fibrotic-like environment.

An alternative to a randomised control design for assessing the efficacy and effectiveness of bracing in adolescent idiopathic scoliosis.

Randomised controlled trials (RCTs) that assessed the efficacy of bracing for adolescent idiopathic scoliosis have suffered from small sample sizes, low compliance and lack of willingness to participate. The aim of this study was to assess the feasibility of a comprehensive cohort study for evaluating both the efficacy and the effectiveness of bracing in patients with adolescent idiopathic scoliosis. Patients with curves at greater risk of progression were invited to join a randomised controlled trial. Those who declined were given the option to remain in the study and to choose whether they wished to be braced or observed. Of 87 eligible patients (5 boys and 63 girls) identified over one year, 68 (78%) with mean age of 12.5 years (10 to 15) consented to participate, with a mean follow-up of 168 weeks (0 to 290). Of these, 19 (28%) accepted randomisation. Of those who declined randomisation, 18 (37%) chose a brace. Patients who were more satisfied with their image were more likely to choose bracing (Odds Ratio 4.1; 95% confidence interval 1.1 to 15.0; p = 0.035). This comprehensive cohort study design facilitates the assessment of both efficacy and effectiveness of bracing in patients with adolescent idiopathic scoliosis, which is not feasible in a conventional randomised controlled trial.

Enrichment of committed human nucleus pulposus cells expressing chondroitin sulfate proteoglycans under alginate encapsulation.

OBJECTIVE: Intervertebral disc (IVD) degeneration is associated with a malfunction of the nucleus pulposus (NP). Alginate culturing provides a favorable microenvironment for the phenotypic maintenance of chondrocyte-like NP cells. However, NP cells are recently evidenced to present heterogeneous populations, including progenitors, fibroblastic cells and primitive NP cells. The aim of this study is to profile the phenotypic changes of distinct human NP cells populations and describe the dynamic expression of chondroitin sulfate glycosaminoglycans (CS-GAGs) in extended alginate encapsulation. METHOD: Non-degenerated (ND-NPC) and degenerated (D-NPC) NP cells were expanded in monolayers, and subject to 28-day culture in alginate after serial passaging. CS-GAG compositional expression in monolayer-/alginate-cultured NP cells was evaluated by carbohydrate electrophoresis. Cellular phenotypic changes were assessed by immunologic detection and gene expression analysis. RESULTS: Relative to D-NPC, ND-NPC displayed remarkably higher expression levels of chondroitin-4-sulfate GAGs over the 28-day culture. Compared with monolayer culture, ND-NPC showed increased NP marker expression of KRT18, KRT19, and CDH2, as well as chondrocyte markers SOX9 and MIA in alginate culture. In contrast, expression of fibroblastic marker COL1A1, COL3A1, and FN1 were reduced. Interestingly, ND-NPC showed a loss of Tie2+ but gain in KRT19+/CD24+ population during alginate culture. In contrast, D-NPC showed more consistent expression levels of NP surface markers during culture. CONCLUSION: We demonstrate for the first time that extended alginate culture selectively enriches the committed NP cells and favors chondroitin-4-sulfate proteoglycan production. These findings suggest its validity as a model to investigate IVD cell function.

Mesenchymal stem cell-collagen microspheres for articular cartilage repair: cell density and differentiation status.

Mesenchymal stem cells (MSC) hold promise for cartilage repair. A microencapsulation technique was previously established to entrap MSC in collagen microspheres, and the collagen fibrous meshwork was found to be an excellent scaffold for supporting MSC survival, growth and differentiation. This study investigates the importance of cell density and differentiation status of MSC-collagen microspheres in cartilage repair. MSC were isolated from rabbit bone marrow and encapsulated in collagen microspheres. The effects of pre-differentiating the encapsulated MSC into chondrogenic lineages and different cell densities on cartilage repair were investigated in rabbits. Implantation of undifferentiated collagen-MSC microspheres formed hyaline-like cartilage rich in type II collagen and glycosaminoglycans (GAG) at 1month post-implantation. By 6months, hyaline cartilage rich in type II collagen and GAG, but negative for type I collagen, and partial zonal organization were found in both undifferentiated and chondrogenically differentiated groups in the high cell density group. The undifferentiated group and high cell density group significantly improved the O'Driscoll histological score. Moreover, the undifferentiated group significantly increased the GAG content. The mechanically differentiated group showed stiffer but thinner cartilage, while the undifferentiated group showed thicker but softer cartilage compared with their respective contra-lateral controls. This work suggests that a higher local cell density favors cartilage regeneration, regardless of the differentiation status of MSC, while the differentiation status of MSC does significantly affect regeneration outcomes.

The effect of excision of the posterior arch of C1 on C1/C2 fusion using transarticular screws.

Transarticular screw fixation with autograft is an established procedure for the surgical treatment of atlantoaxial instability. Removal of the posterior arch of C1 may affect the rate of fusion. This study assessed the rate of atlantoaxial fusion using transarticular screws with or without removal of the posterior arch of C1. We reviewed 30 consecutive patients who underwent atlantoaxial fusion with a minimum follow-up of two years. In 25 patients (group A) the posterior arch of C1 was not excised (group A) and in five it was (group B). Fusion was assessed on static and dynamic radiographs. In selected patients CT imaging was also used to assess fusion and the position of the screws. There were 15 men and 15 women with a mean age of 51.2 years (23 to 77) and a mean follow-up of 7.7 years (2 to 11.6). Stable union with a solid fusion or a stable fibrous union was achieved in 29 patients (97%). In Group A, 20 patients (80%) achieved a solid fusion, four (16%) a stable fibrous union and one (4%) a nonunion. In Group B, stable union was achieved in all patients, three having a solid fusion and two a stable fibrous union. There was no statistically significant difference between the status of fusion in the two groups. Complications were noted in 12 patients (40%); these were mainly related to the screws, and included malpositioning and breakage. The presence of an intact or removed posterior arch of C1 did not affect the rate of fusion in patients with atlantoaxial instability undergoing C1/C2 fusion using transarticular screws and autograft.

Photochemically crosslinked collagen annulus plug: a potential solution solving the leakage problem of cell-based therapies for disc degeneration.

Intra-disc injection of mesenchymal stem cells (MSCs) to treat disc degeneration may lead to unfavorable complications, particularly osteophyte formation. Development of an effective method to block the injection portal, prevent the leakage of injected cells and materials and, hence, prevent osteophyte formation is of the utmost importance before MSC-based therapies can be applied in a clinical setting. Here we seek to alleviate the cell leakage problem and the associated complication osteophyte formation by developing an injectable annulus plug to block the injection portal during intra-disc delivery. Specifically, we fabricated a needle-shaped collagen plug by photochemical crosslinking and successfully delivered it intra-discally, in association with MSCs in collagen microsphere carriers, using a custom-made delivery device. The mechanical performance of the plug and its effectiveness in reducing cell leakage were evaluated ex vivo under compression and in torsion push-out tests. The results demonstrate that the plug survived physiologically relevant loadings and significantly reduced leakage and enhanced retention of the injected materials. Finally, a pilot in vivo study in rabbits was conducted to evaluate the performance of the plug. Microcomputed tomography imaging and histology revealed that the plug significantly reduced osteophyte formation. This work suggests the potential of the annulus plug as an adjunct or annulus closure device for intra-disc delivery of cells and materials.

Effects of nucleus pulposus cell-derived acellular matrix on the differentiation of mesenchymal stem cells.

Recent attempts to treat disc degeneration with mesenchymal stem cells (MSCs) showed encouraging results. Differentiating MSCs towards nucleus pulposus cell (NPC)-like lineages represents a speculative mechanism. Niche factors including hypoxia, growth factors and cell-cell interactions have been suggested but the matrix niche factor has not been studied. Our collagen microencapsulation provides a 3D model to study matrix niche as it enables the encapsulated cells to remodel the template matrix. We previously demonstrated the chondro-inductive role of of chondrocytes-derived matrix in MSCs and showed that NPCs maintained their phenotype and remodeled the template matrix of collagen microspheres into a glycosaminoglycan (GAG)-rich one. Here we aim to study the effects of NPC-derived matrix on MSC differentiation towards NPC-like lineages by firstly producing an NPC-derived matrix in collagen microspheres, secondly optimizing a decellularization protocol to discard NPCs yet retaining the matrix, thirdly repopulating the acellular NPC-derived matrix with MSCs and fourthly evaluating their phenotype. Finally, we injected these microspheres in a pilot rabbit disc degeneration model. Results showed that NPCs survived, maintained their phenotypic markers and produced GAGs. A decellularization protocol with maximal removal of the NPCs, minimal loss in major matrix components and partial retention of NPC-specific markers was identified. The resulting acellular matrix supported MSC survival and matrix production, and up-regulated the gene expression of NPC markers including type II collagen and glypican 3. Finally, injection of MSC in these microspheres in rabbit degenerative disc better maintained hydration level with more pronounced staining of GAGs and type II collagen than controls.

A new mechanism of injury in ankylosing spondylitis: non-traumatic hyperextension causing atlantoaxial subluxation.

Ankylosing spondylitis (AS) is a progressive multisystem chronic inflammatory disorder. The hallmark of this pathological process is a progressive fusion of the zygapophyseal joints and disc spaces of the axial skeleton, leading to a rigid kyphotic deformity and positive sagittal balance. The ankylosed spine is unable to accommodate normal mechanical forces, rendering it brittle and susceptible to injury. Traumatic hyperextension injury of the cervical spine leading to atlantoaxial subluxation (AAS) in AS patients can often be fatal. We report a non-traumatic mechanism of injury in AS progressing to AAS attributable to persistent hyperextension, which resulted in fatal migration of C2 through the foramen magnum.

Fabrication of micropillar substrates using replicas of alpha-particle irradiated and chemically etched PADC films.

We proposed a simple method to fabricate micropillar substrates. Polyallyldiglycol carbonate (PADC) films were irradiated by alpha particles and then chemically etched to form a cast with micron-scale spherical pores. A polydimethylsiloxane (PDMS) replica of this PADC film gave a micropillar substrate with micron-scale spherical pillars. HeLa cells cultured on such a micropillar substrate had significantly larger percentage of cells entering S-phase, attached cell numbers and cell spreading areas.

The role of cryopreservation in the biomechanical properties of the intervertebral disc.

Implantation of intervertebral disc (IVD) allograft or tissue engineered disc constructs in the spine has emerged as an alternative to artificial disc replacement for the treatment of severe degenerative disc disease (DDD). Establishment of a bank of cryopreserved IVD allografts enables size matching and facilitates logistics for effective clinical management. However, the biomechanical properties of cryopreserved IVDs have not been previously reported. This study aimed to assess if cryopreservation with different concentrations of cryopreservant agents (CPA) would affect the dynamic viscoelastic properties of the IVD. Whole porcine lumbar IVDs (n = 40) were harvested and processed using various concentrations of CPA, 0 % CPA, 10 % CPA and 20 % CPA. The discs were cryopreserved using a stepwise freezing protocol and stored in liquid nitrogen. After four weeks of storage, the cryopreserved IVDs were quickly thawed at 37 °C for dynamic viscoelastic testing. The apparent modulus, elastic modulus (G'), viscous modulus (G") and loss modulus (G"/G') were calculated and compared to a fresh control group. Cryopreserved IVD without cryopreservants was significantly stiffer than the control. In the dynamic viscoelastic testing, cryopreservation with the use of CPA was able to preserve both G' and G" of an IVD. No significant differences were found between fresh IVD and IVD cryopreserved with 10 % CPA or 20 % CPA. This study demonstrated that CPAs at an optimal concentration could preserve the mechanical properties of the IVD allograft and can provide further credence for the application of long-term storage of IVD allografts for disc transplantation or tissue engineered construct applications.

Biochemical characterization of the cell-biomaterial interface by quantitative proteomics.

Surface topography and texture of cell culture substrata can affect the differentiation and growth of adherent cells. The biochemical basis of the transduction of the physical and mechanical signals to cellular responses is not well understood. The lack of a systematic characterization of cell-biomaterial interaction is the major bottleneck. This study demonstrated the use of a novel subcellular fractionation method combined with quantitative MS-based proteomics to enable the robust and high-throughput analysis of proteins at the adherence interface of Madin-Darby canine kidney cells. This method revealed the enrichment of extracellular matrix proteins and membrane and stress fibers proteins at the adherence surface, whereas it shows depletion of extracellular matrix belonging to the cytoplasmic, nucleus, and lateral and apical membranes. The asymmetric distribution of proteins between apical and adherence sides was also profiled. Apart from classical proteins with clear involvement in cell-material interactions, proteins previously not known to be involved in cell attachment were also discovered.

Nano-scale surface morphology, wettability and osteoblast adhesion on nitrogen plasma-implanted NiTi shape memory alloy.

Plasma immersion ion implantation (PIII) is an effective method to increase the corrosion resistance and inhibit nickel release from orthopedic NiTi shape memory alloy. Nitrogen was plasma-implanted into NiTi using different pulsing frequencies to investigate the effects on the nano-scale surface morphology, structure, wettability, as well as biocompatibility. X-ray photoelectron spectroscopy (XPS) results show that the implantation depth of nitrogen increases with higher pulsing frequencies. Atomic force microscopy (AFM) discloses that the nano-scale surface roughness increases and surface features are changed from islands to spiky cones with higher pulsing frequencies. This variation in the nano surface structures leads to different surface free energy (SFE) monitored by contact angle measurements. The adhesion, spreading, and proliferation of osteoblasts on the implanted NiTi surface are assessed by cell culture tests. Our results indicate that the nano-scale surface morphology that is altered by the implantation frequencies impacts the surface free energy and wettability of the NiTi surfaces, and in turn affects the osteoblast adhesion behavior.

A biomimetic hierarchical scaffold: natural growth of nanotitanates on three-dimensional microporous Ti-based metals.

Nanophase materials are promising alternative implant materials in tissue engineering. Here we report for the first time the large-scale direct growth of nanostructured bioactive titanates on three-dimensional (3D) microporous Ti-based metal (NiTi and Ti) scaffolds via a facile low temperature hydrothermal treatment. The nanostructured titanates show characteristics of 1D nanobelts/nanowires on a nanoskeleton layer. Besides resembling cancelous bone structure on the micro/macroscale, the 1D nanostructured titanate on the exposed surface is similar to the lowest level of hierarchical organization of collagen and hydroxyapatite. The resulting surface displays superhydrophilicity and favors deposition of hydroxyapatite and accelerates cell attachment and proliferation. The remarkable simplicity of this process makes it widely accessible as an enabling technique for applications from engineering materials treatment including energy-absorption materials and pollution-treatment materials to biotechnology.

Right hip adduction deficit and adolescent idiopathic scoliosis.

PURPOSE: To determine whether right hip adduction deficit is associated with adolescent idiopathic scoliosis. METHODS: 102 adolescents (mean age, 14 years) with idiopathic scoliosis were prospectively studied. Their spinal curve pattern (according to Lenke's classification), curve severity (by Cobb's angle), and hip adduction ranges of both sides were recorded. Additional factors that may affect hip adduction range including the preferred leg during standing, the presence of hip flexor tightness, and the side of the dominant leg were also assessed. RESULTS: The mean Cobb's angle was 27 degrees. The difference in hip adduction range between the right and left hips was 5 degrees (p<0.05). Of 102 patients, 64 had an adduction range deficit of the right hip, 4 of the left hip, and 34 had no difference. Patients with >10 degrees of right hip adduction deficit were associated with a higher proportion of left leg dominance than those with less than or equal to 10 degrees of right hip adduction deficit (18% vs 4%). CONCLUSION: Left leg dominance may play a role in right hip adduction deficit and scoliosis.