Comparison of Different Bone Age Methods and Chronological Age in Prediction of Remaining Growth Around the Knee.

BACKGROUND: Bone age (BA) has been shown to be superior to chronological age (CA) when predicting remaining growth. However, it is not known whether the calculations are more accurate when BA is assessed by the Greulich and Pyle (GP) or the Sauvegrain (SG) methods. The aim of our study was to identify the method which gives an estimate closest to actual growth in the lower extremities. METHODS: Leg length radiographs, hand radiographs, and elbow radiographs were simultaneously obtained during the adolescent growth spurt (10 to 16 years) in 52 children treated for LLD, with radiographic follow-up of segmental length (femur, tibia, and foot) until skeletal maturity, were randomly selected from a local institutional register. BA, according to GP and SG, were manually rated, and BA based on the GP method was additionally assessed by the automated BoneXpert (BX) method. The remaining growth was calculated based on the White-Menelaus method for both BA methods (GP, SG), the combination of the 2 methods, GP by BX, CA, and the combination of CA and GP by BX. Estimated growth was compared with the actual growth in the distal femur and proximal tibia from the time of BA determination until skeletal maturity. RESULTS: For all included methods, the average calculated remaining growth was higher compared with the actual growth. The mean absolute difference between calculated remaining growth and actual growth in the femur and tibia was lowest using GP by BX [0.66 cm (SD 0.51 cm) and 0.43 cm (SD 0.34 cm)] and highest using CA [1.02 (SD 0.72) and 0.67 (SD 0.46)]. It was a significant association between calculated growth and the difference between actual and calculated growth for the SG method ( P =<0.001). CONCLUSION: During the adolescent growth spurt, the GP method compared with the SG method and CA gives the most accurate estimate of remaining growth around the knee according to our results. CLINICAL RELEVANCE: In calculations of remaining growth around the knee, BA assessment by the GP atlas or BX method should be used as the parameter of biological maturity.

A comparison of 3 different methods for assessment of skeletal age when treating leg-length discrepancies: an inter- and intra-observer study.

Background and purpose - Skeletal maturity is a crucial parameter when calculating remaining growth in children. We compared 3 different methods, 2 manual and 1 automated, in the radiological assessment of bone age with respect to precision and systematic difference. Material and methods - 66 simultaneous examinations of the left hand and left elbow from children treated for leg-length discrepancies were randomly selected for skeletal age assessment. The radiographs were anonymized and assessed twice with at least 3 weeks' interval according to the Greulich and Pyle (GP) and Sauvegrain (SG) methods by 5 radiologists with different levels of experience. The hand radiographs were also assessed for GP bone age by use of the automated BoneXpert (BX) method for comparison. Results - The inter-observer intraclass correlation coefficient (ICC) was 0.96 for the GP and 0.98 for the SG method. The inter- and intra-observer standard error of the measurement (SEm) was 0.41 and 0.32 years for the GP method and 0.27 and 0.21 years for the SG method with a significant difference (p < 0.001) between the methods and between the experienced and the less experienced radiologists for both methods (p = 0.003 and p < 0.001). In 25% of the assessments the discrepancy between the GP and the SG method was > 1 year. There was no systematic difference comparing either manual method with the automatic BX method. Interpretation - With respect to the precision of skeletal age determination, we recommend using the SG method or preferably the automated BX method based on GP assessments in the calculation of remaining growth.

Limb lengthening and deformity correction with externally controlled motorized intramedullary nails: evaluation of 50 consecutive lengthenings.

Background and purpose - Limb lengthening with an intramedullary motorized nail is a relatively new method. We investigated if lengthening nails are reliable constructs for limb lengthening and deformity correction in the femur and the tibia. Patients and methods - 50 lengthenings (34 Precice and 16 Fitbone devices) in 47 patients (mean age 23 years [11-61]) with ≥12 months follow-up are included in this study. 30 lengthenings were done due to congenital and 20 because of posttraumatic deformity (21 antegrade femora, 23 retrograde femora, 6 tibiae). Initial deformities included a mean shortening of 42 mm (25-90). In 15 patients, simultaneous axial correction was done using the retrograde nailing technique. Results - The planned amount of lengthening was achieved in all but 2 patients. 5 patients who underwent simultaneous axial correction showed minor residual deformity; unintentionally induced minor deformities were found in the frontal and sagittal plane. The consolidation index was 1.2 months/cm (0.6-2.5) in the femur and 2.5 months/cm (1.6-4.0) in the tibia. 2 femoral fractures occurred in retrograde femoral lengthenings after consolidation due to substantial trauma. There were 8 complications, all of which were correctable by surgery, with no permanent sequelae. Interpretation - Controlled acute axial correction of angular deformities and limb lengthening can be achieved by a motorized intramedullary nail. A thorough preoperative planning and intraoperative control of alignment are required to avoid residual and unintentionally induced deformity. In the femur relatively fast consolidation could be observed, whereas healing was slower in the tibia.

Limb lengthening and deformity correction of congenital and acquired deformities in children using the Taylor Spatial Frame.

Background and purpose - Hexapod ring fixators such as the Taylor Spatial Frame (TSF) have shown good outcomes. However, there have only been a few studies comparing the use of TSF with various etiologies of the deformity. We compared the use of TSF in congenital and acquired deformities in children. Patients and methods - We reviewed 213 lower extremity reconstructive procedures with the TSF in 192 patients who were operated between October 2000 and October 2015. 128 procedures (67 proximal tibiae, 51 distal femora, and 10 distal tibiae) in 117 children (median age 14 (4-18) years; 59 girls) fulfilled the inclusion criteria. 89 procedures were done in children with congenital deformities (group C) and 39 were done in children with acquired deformities (group A). Outcome parameters were lengthening and alignment achieved, lengthening index, complications, and analysis of residual deformity in a subgroup of patients. Results - Mean lengthening achieved was 3.9 (1.0-7.0) cm in group C and 3.7 (1.0-8.0) cm in group A (p = 0.5). Deformity parameters were corrected to satisfaction in all but 3 patients, who needed further surgery for complete deformity correction. However, minor residual deformity was common in one-third of the patients. The mean lengthening index was 2.2 (0.8-10) months/cm in group C and 2.0 (0.8-6) months/cm in group A (p = 0.7). Isolated analysis of all tibial and femoral lengthenings showed similar lengthening indices between groups. Complication rates and the need for secondary surgery were much greater in the group with congenital deformities. Interpretation - The TSF is an excellent tool for the correction of complex deformities in children. There were similar lengthening indices in the 2 groups. However, congenital deformities showed a high rate of complications, and should therefore be addressed with care.

Hemiepiphysiodesis: similar treatment time for tension-band plating and for stapling: a randomized clinical trial on guided growth for idiopathic genu valgum.

BACKGROUND: In children with angulating deformities of the lower limbs, hemiepiphysiodesis can be used to guide growth to achieve better alignment at skeletal maturity. Traditionally, this has been performed with staples. The tension-band plating technique is new and it has been advocated because it is believed to reduce the risk of premature closure of the growth plate compared to stapling. The benefit of the tension-band plating technique has not yet been proven in experimental or randomized clinical studies. METHODS: We performed a randomized clinical trial in which 26 children with idiopathic genu valgum were allocated to stapling or tension-band plating hemiepiphysiodesis. Time to correction of the deformity was recorded and changes in angles on long standing radiographs were measured. Pain score using visual analog scale (VAS) was recorded for the first 72 h postoperatively. Analgesics taken were recorded by the parents. RESULTS: Mean treatment times for stapling hemiepiphysiodesis (n = 10) and for tension-band plating hemiepiphysiodesis (n = 10) were similar. Postoperative VAS scores and consumption of analgesics were also similar in both groups. No hardware failure or wound-related infection was observed. INTERPRETATION: Treatment time for the 2 treatment modalities was not significantly different in this randomized clinical trial. Tension-band plating and stapling appeared to have a similar effect regarding correction of genu valgum. We cannot rule out type-II error and the possibility that our study was underpowered. ClinicalTrials.gov Identifier: NCT01641354.

Calcium phosphate cement enhances primary stability of open-wedge high-tibial osteotomies.

We investigated if injectable calcium phosphate cement improves primary stability in open-wedge high-tibial osteotomy. A 10 mm open-wedge osteotomy was performed on eight pairs of preserved cadaver tibiae and seven pairs of composite (Sawbone) left tibiae. Osteosynthesis was performed with the Dynafix plate system. The gap resulting from surgery either was filled with 15 g injectable calcium phosphate cement in half the bones or was left untreated. The composite tibiae were loaded at a ramp speed of 20 mm/min up to 20 kN. The cadaver tibiae were exposed to 100 cycles with a maximum compressive force of 2,250 N. After 100 cycles of loading with 2,250 N, the final loaded displacement was 1.2 mm for the cadaver tibiae treated with injectable calcium phosphate cement as compared with 3.6 mm for the empty defects (P = 0.028). All the seven empty defect composite specimens failed prior to 20 kN (median 2.8 kN) as compared with five of the injectable calcium phosphate cement specimens (median 17 kN) (P = 0.005). The injection of injectable calcium phosphate cement following open-wedge osteotomy of the proximal tibia increases the initial stability of the bone as measured by load-to-failure and displacement after cyclic loading. Clinical studies are ongoing to investigate whether injectable calcium phosphate cement also has clinical advantage on wedge healing and stability.

Parathyroid hormone PTH(1-34) increases the volume, mineral content, and mechanical properties of regenerated mineralizing tissue after distraction osteogenesis in rabbits.

BACKGROUND AND PURPOSE: Parathyroid hormone (PTH) has attracted considerable interest as a bone anabolic agent. Recently, it has been suggested that PTH can also enhance bone repair after fracture and distraction osteogenesis. We analyzed bone density and strength of the newly regenerated mineralized tissue after intermittent treatment with PTH in rabbits, which undergo Haversian bone remodeling similar to that in humans. METHODS: 72 New Zealand White rabbits underwent tibial mid-diaphyseal osteotomy and the callus was distracted 1 mm/day for 10 days. The rabbits were divided into 3 groups, which received injections of PTH 25 microg/kg/day for 30 days, saline for 10 days and PTH 25 microg/kg/day for 20 days, or saline for 30 days. At the end of the study, the rabbits were killed and the bone density was evaluated with DEXA. The mechanical bone strength was determined by use of a 3-point bending test. RESULTS: In the 2 PTH-treated groups the regenerate callus ultimate load was 33% and 30% higher, absorbed energy was 100% and 65% higher, BMC was 61% and 60% higher, and callus tissue volume was 179% and 197% higher than for the control group. INTERPRETATION: We found that treatment with PTH during distraction osteogenesis resulted in substantially higher mineralized tissue volume, mineral content, and bending strength. This suggests that treatment with PTH may benefit new bone formation during distraction osteogenesis and could form a basis for clinical application of this therapy in humans.

Low rate of clinically important avascular necrosis of the femoral head after Ludloff's procedure.

INTRODUCTION: Ludloff's procedure for open reduction of congenital dislocation of the hip (CDH) is recommended for its minimal tissue damage, but is criticised for the risk of late avascular necrosis (AVN) of the femoral head. The aim of present study was primarily to assess the risk of late AVN of the femoral head and secondly the range of motion (ROM) of the hip and the quality of life in children following Ludloff's procedure. METHODS AND MATERIALS: 13 hips in 11 children after Ludloff's procedure due to CDH were included retrospectively from 1997 to 2005 at Aarhus University Hospital. Radiographs were evaluated for the presence of AVN of the femoral head and classified according to the Bucholz and Ogden classification, with type 2-4 having clinical relevance. A clinical examination included range of motion (ROM) and leg length discrepancy (LLD) measurements. The HAGOS hip questionnaire evaluated activity, participation and quality of life. RESULTS: No severe type 3-4 AVN was observed. 2 type 2 and 5 type 1 were observed. AVN was observed in 7 of the 13 operated hips (54%). An 8.6° difference in flexion for unilaterally treated hips was observed (p<0.02). 8 of 11 patients had minor LLD (range 0.5-2 cm). CONCLUSIONS: Only minor AVN of clinical importance was seen after Ludloff's procedure.

Surgery in hemophilia. The general view: patient selection, timing, and preoperative assessment.

Although often overlooked, the life of the patient with severe hemophilia is characterized by both intermittent and chronic pain. Bleeds into joints and muscles cause extensive pressure on sensory nerves and, following recurrent bleeds, joint destruction, and synovial reaction is accompanied by constant pains that are frequently mistaken for further bleeding. The orthopedic surgeon may break the vicious cycle of chronic synovitis by excising inflamed and hypertrophic synovium or severely damaged cartilage and adjacent bone ends, and implanting an artificial joint. Numerous technical solutions are now available and orthopedic surgery is increasingly on offer to those hemophilia patients who, since childhood, have been victims of insufficiently treated bleeds because no or limited treatment was available, and because the concept of prophylaxis had not yet been developed. Nonetheless, orthopedic surgery in patients with hemophilia requires much more effort and planning than surgery in non-hemophilic patients. In this overview, we will address issues related to surgery in hemophilic patients, as well as some practical issues related to the timing of surgery, preoperative testing, perioperative hemostasis, and patient rehabilitation.

Effects of parathyroid hormone on newly regenerated bone during distraction osteogenesis in a rabbit tibial lengthening model. A pilot study.

OBJECTIVE: The overall purpose of the study is to determine the effects of parathyroid hormone (PTH) (1-34) on bone formation in regenerated and surrounding bone of distracted callus during limb lengthening in rabbits. Additionally the aim of the pilot study is to titrate the optimal dose of PTH for distraction osteogenesis treatment in rabbits' tibial lengthening model. MATERIALS AND METHODS: A total of 18 rabbits underwent right tibia lengthening by callus distraction. Lengthening was started 5 days postoperatively 1 mm/day for a 10-day period and consolidation of 20 days followed. Rabbits were divided into three groups: group I received PTH (1-34) treatment at a dose of 5 microg/kg/day, group II received treatment with PTH (1-34) at a dose of 25 microg/kg/day; group III rabbits were treated with saline. After euthanasia, tibiae of both legs were dissected free, kept frozen and underwent x-ray analysis, dual x-ray absorptiometry-scanning, microcomputed tomography scanning and three-dimensional evaluation and mechanical test followed. RESULTS: Over all, during distraction osteogenesis in a new regenerated bone, PTH (1-34) treatment with two different doses of 5 microg/kg/day and 25 microg/kg/day increased callus cross-sectional area, callus bone mineral density and bone mineral content, bone volume density; dramatically increased trabecular number with slight increase in trabecular thickness, whereas decreased trabecular separation, bone surface density and decreased degree of anisotropy when compared to control group animals. CONCLUSION: PTH (1-34) treatment improved mineralization, structural indices of regenerated distracted rabbits' tibiae, whereas treatment at a dose of 25 microg/kg/day PTH (1-34) was significantly more effective than 5 microg/kg/day PTH(1-34) dose treatment when compared to control group. Bigger dose has been chosen for the main study.

The biology of bone lengthening.

Distraction osteogenesis biologically resembles fracture healing with distinctive characteristics notably in the distraction phase of osteogenesis. In the latency phase of bone lengthening, like in the inflammatory phase of fracture repair, interleukines are released and act with growth factors released from platelets in the local haematoma, leading to attraction, proliferation and differentiation of mesenchymal stem cells into osteoblasts and other differentiated mesenchymal cells. These in turn produce matrix, collagen fibers and growth factors. A callus containing cells, collagen fibers, osteoid and cartilage matrix is formed. Provided stable fixation, distraction will trigger intramembranous bone formation. As distraction proceeds, the distraction gap develops five distinctive zones with unmineralized bone in the middle, remodelling bone peripherally, and mineralizing bone in between. During consolidation, the high concentration of anabolic growth factors in the regenerate diminishes with time as remodelling takes over to form mature cortical and cancellous bone. Systemic disease, congenital bone deficiencies, medications and substance abuse can influence the quality and quantity of regenerate bone, usually in a negative way. The regenerate bone can be manipulated when needed by using injection of mesenchymal stem cells and platelets, growth factors (BMP-2 and -7), and systemic medications (bisphosphonates and parathyroid hormone). Growth factors and systemic anabolic and antiresorptive drugs are prescribed on special indications, while distraction osteogenesis is not an authorized indication. To some extent, however, these compounds can be used off-label. Use in children presents special problems since growth factors and specific anabolic medications may involve a risk of inducing cancer.

Effects of hyaluronan on three-dimensional microarchitecture of subchondral bone tissues in guinea pig primary osteoarthrosis.

Hyaluronan (HA) has received increasing interest as a potential agent in therapeutic intervention in osteoarthrosis (OA). HA has been shown to reduce arthritic lesions in experimental animal models of articular cartilage injury. This study was to investigate the effects of high molecular weight HA intra-articular injection on subchondral bone tissues. Fifty-six male guinea pigs were randomly divided into 5 groups. During the initial 2.5-month period, three groups received intra-articular injection of HA 0.4 mg/kg/week for 5 weeks in both knee joints. Two control groups received vehicle. After 2.5 months, one HA group and one control group were sacrificed. The remaining 3 groups (5.5-month groups) were left for an additional 3 months before sacrifice during which time one HA group received additional 5 weeks injections, one HA group received no more injections, and the control group received vehicle. The left tibiae were harvested and micro-CT scanned to quantify three-dimensional microarchitecture of subchondral bone plate, cancellous bone and cortical bone, followed by mechanical testing and collagen and mineral determinations. All HA-treated groups had almost normal cartilage, whereas the control groups had typical OA-related cartilage degradation. In the 2.5-month group, HA resulted in significantly decreased subchondral plate volume fraction and thickness and HA-treated cancellous bone had significantly lower bone volume fraction, and typical rod-like structure. After 5.5 months, these changes were more pronounced, with an additional marked decrease in connectivity and bone surface density. HA-treated cortical bone had significantly greater volume fraction at both observation times. HA groups had greater bone mineral concentration and reduced collagen to mineral ratio with similar mechanical properties of cancellous bone but less stiff cortical bone. The effects of HA on cartilage and subchondral bone were maintained when treatment was discontinued. In summary, HA effectively protects against cartilage degeneration, decreases subchondral bone density and thickness, changes trabecular structure toward rod-like, so that subchondral bone becomes more compliant and thereby reduces cartilage stress during impact loading. HA preserved cancellous bone mechanical properties by increasing bone mineralization. Early HA administration is effective for intervention of OA initiation and progression, and short-term early HA treatment is sufficient to maintain treatment effects.

Age-related variations in the microstructure of human tibial cancellous bone.

A thorough understanding of the microstructure of cancellous bone is crucial for diagnosis, prophylaxis, and treatment of age-related skeletal diseases. Until now, little has been known about age-related variations in the microstructure of peripheral cancellous bone. This study quantified age-related changes in the three-dimensional (3D) microstructure of human tibial cancellous bone. One hundred and sixty cylindrical cancellous bone specimens were produced from 40 normal proximal tibiae from 40 donors, aged 16-85 years. These specimens were micro-computed tomography (micro-CT) scanned, and microstructural properties were determined. The specimens were then tested in compression to obtain Young's modulus. The degree of anisotropy, mean marrow space volume, and bone surface-to-volume ratio increased significantly with age. Bone volume fraction, mean trabecular volume, and bone surface density decreased significantly with age. Connectivity did not have a general relationship with age. Bone volume fraction together with anisotropy best predicted Young's modulus. Age-related changes in the microstructural properties had the same trends for both medial and lateral condyles of the tibia. The observed increase of anisotropy and constant connectivity suggest a bone remodeling mechanism that may reorient trabecular volume orientation in aging tibial cancellous bone. The aging trabeculae align more strongly to the primary direction--parallel to the tibial longitudinal loading axis.

Effects of locally applied vascular endothelial growth factor (VEGF) and VEGF-inhibitor to the rabbit tibia during distraction osteogenesis.

INTRODUCTION: Therapeutic angiogenesis, a novel concept in tissue engineering, is neo-formation of blood vessels in a tissue upon delivery of an angiogenic growth factor to the tissue. We hypothesised that therapeutic angiogenesis could enhance bone formation and challenged the hypothesis in an experimental model of distraction osteogenesis. METHODS: Rabbits, divided into three equal groups of 12, had their right tibia lengthened by distraction osteogenesis. A mini-osmotic pump delivered to the osteotomy gap either recombinant human vascular endothelial growth factor (VEGF), VEGF-inhibitor, or vehicle alone during the latency and distraction phase. After consolidation, we assessed bone blood flow by radioactive microsphere entrapment, measured torsional stiffness and bone mineral content, and did histomorphometry. RESULTS: VEGF and VEGF-inhibitor treatment failed to influence bone blood flow, torsional stiffness, bone mineral content and histomorphometric indices of the bone regenerate. However, VEGF treatment increased the blood flow in bone of the distracted limb and VEGF-inhibitor treatment decreased bone blood flow. CONCLUSION: The regenerate was unresponsive to VEGF and VEGF-inhibitor treatment in contrast to the neighbouring bone, which implies different biological properties of the vasculature in native and regenerating bone. VEGF is not recommended for enhancement of bone formation in this setting.

Mutual associations among microstructural, physical and mechanical properties of human cancellous bone.

Previous studies have shown that low-density, rod-like trabecular structures develop in regions of low stress, whereas high-density, plate-like trabecular structures are found in regions of high stress. This phenomenon suggests that there may be a close relationship between the type of trabecular structure and mechanical properties. In this study, 160 cancellous bone specimens were produced from 40 normal human tibiae aged from 16 to 85 years at post-mortem. The specimens underwent micro-CT and the microstructural properties were calculated using unbiased three-dimensional methods. The specimens were tested to determine the mechanical properties and the physical/compositional properties were evaluated. The type of structure together with anisotropy correlated well with Young's modulus of human tibial cancellous bone. The plate-like structure reflected high mechanical stress and the rod-like structure low mechanical stress. There was a strong correlation between the type of trabecular structure and the bone-volume fraction. The most effective microstructural properties for predicting the mechanical properties of cancellous bone seem to differ with age.

Parathyroid hormone--possible future drug for orthopedic surgery.

Parathyroid hormone naturally secreted by the parathyroid glands is a potent anabolic agent for bone. Parathyroid hormone is primarily thought of as a catabolic protein involved in the physiologic release of calcium from bone. Whereas during recent years, a number of animal studies and clinical trials have demonstrated that intermittent parathyroid hormone administration induces anabolic effects on both cancellous and cortical bone, enhances bone mass and increases mechanical strength of the bones. Most of the studies, both animal and human, have addressed the treatment of osteoporosis and parathyroid hormone represents an important new advance in the therapy of osteoporosis. Few studies have investigated the effect of intermittent parathyroid hormone treatment in the field of orthopedics on fracture healing and fixation of orthopedic implants. The results of those studies indicated an enhancement of fracture healing, faster bone repair and better fixation of the implant. Recently there were few animal studies started to investigate the effects of parathyroid hormone treatment on bone formation in regenerated and surrounding bone of distracted callus during limb lengthening. Distraction osteogenesis is a technique for bone lengthening that is widely used clinically and experimentally. Newly forming bone during distraction osteogenesis is expected to be an appropriate pattern for parathyroid hormone anabolic effect. Preclinical studies as well as clinical trials suggest that parathyroid hormone might be useful as a stimulator of bone formation whereas a lot of questions regarding parathyroid hormone therapy remain unanswered and require further experimental studies and investigations.

[Child orthopedics]. / Børneortopaedi.

Children's fractures are a challenge to the treatment system, in that 17,000 children are treated in Denmark each year. The true burden on patients and society is unknown. It is estimated that 1000 new-born infants are treated for hip instability in Denmark per year, and 30 are diagnosed late. Ultrasound scanning is recommended for secondary screening and selective screening of children at risk. Identification of acetabular dysplasia followed by surgical correction could be an important prophylactic measure, with a potential reduction in expenses to society. To some extent, congenital clubfoot is hereditary. Environmental factors are important, maternal smoking being one. Early operative treatment yields good results. There is a need for prospective registration. Perthes' disease is an idiopathic necrosis of the capital femoral epiphysis. Passive smoking is a significant factor. A young age (< 7 years) and limited necrosis carry a good prognosis, and active treatment can improve the prognosis for the other patients.