Purpose
The primary objective of this study was to quantify the variations of the medial posterior tibial slope (MPTS) and the lateral posterior tibial slope (LPTS), as well as of the medial proximal ...tibial angle (MPTA), and to determine the fraction of patients for which standard techniques including different alignment techniques would result in alteration of the patient’s individual posterior tibial slope (PTS) and MPTA. Furthermore, it was of interest if a positive correlation between PTS and MPTA or between medial and lateral slope exists.
Methods
A retrospective study was performed on CT-scans of 234 consecutively selected European patients undergoing individual total knee replacement. All measurements were done on three-dimensional CAD models, which were generated on the basis of individual CT-scans, including the hip, knee, and ankle center. Measurements included the medial and lateral PTS and the MPTA. PTS was measured as the angle between the patient’s articular surface and a plane perpendicular to the mechanical axis of the tibia in the sagittal plane. MPTA was defined as the angle between the tibial mechanical axis and the proximal articular surface of the tibia in the coronal plane.
Results
Analysis revealed a wide variation of the MPTS, LPTS, and MPTA among the patients. MPTS and LPTS varied significantly both interindividually and intraindividually. The range of PTS was up to 20° for MPTS (from − 4.3° to 16.8°) and for LPTS (from − 2.9 to 17.2°). The mean intraindividual difference between MPTS and LPTS in the same knee was 2.6° (SD 2.0) with a maximum of 9.5°. MPTA ranged from 79.8 to 92.1° with a mean of 86.6° (SD ± 2.4). Statistical analysis revealed a weak positive correlation between MPTA and MPTS.
Conclusion
The study demonstrates a huge interindividual variability in PTS and MPTA as well as significant intraindividual differences in MPTS and LPTS. Therefore, the question arises, whether the use of standard techniques, including fixed PTSs and MPTAs, is sufficient to address every single patient’s individual anatomy.
Level of evidence
III.
After intramedullary nailing of tibia shaft fractures, torsional malalignment greater than 10 degrees occur in up to 41% of operated legs. The reason is the difficult clinical assessment of rotation ...intraoperatively, the large variation in absolute torsion of the tibia, and the absence of established reliable methods to fluoroscopically evaluate tibial rotation and compare with the contralateral side. We present here a fast and low-tech intraoperative method on how to achieve identical tibial torsion of the operated and noninjured side. The method can be used for tibia shaft and metaphyseal fractures and only requires a normal C-arm fluoroscope with 2 monitors. First, a true lateral image of the knee on the noninjured side with the femoral condyles aligned is obtained. Second, with the leg and the C-arm rotation and tilt fixed, the fluoroscope is moved parallel to the patient axis and a lateral ankle image is obtained and saved. The fibula position relative to the tibia at the level of the Volkmann tubercle on the lateral view defines the torsion of the tibia. The sequence described above is repeated on the operated side after implantation of the nail before proximal locking. On the operated side, the fibula position relative to the tibia should be identical to the noninjured side before proximal locking takes place. Otherwise, a rotational malalignment is present and must be corrected. The comparison between operated and noninjured side is easy on a fluoroscope with 2 monitors. The complete examination takes a few minutes and has minor additional radiation exposure. We performed the intraoperative torsion control in 10 patients and performed a postoperative low-dose Computer Tomography-control of the torsion of both legs and found the rotational deformity to be less than 10 degrees in all patients.
Background
Previous designs of internal bone lengthening devices have been fraught with imprecise distraction, resulting in nerve injuries, joint contractures, nonunions, and other complications. ...Recently, a magnet-operated PRECICE
®
nail (Ellipse Technologies, Inc, Irvine, CA, USA) was approved by the FDA; however, its clinical efficacy is unknown.
Questions/purposes
We evaluated this nail in terms of (1) accuracy and precision of distraction, (2) effects on bone alignment, (3) effects on adjacent-joint ROM, and (4) frequency of implant-related and non-implant-related complications.
Methods
We reviewed medical and radiographic records of 24 patients who underwent femoral and/or tibial lengthening procedures using the PRECICE
®
nail from August 2012 to July 2013 for conditions of varied etiology, the most common being congenital limb length discrepancy, posttraumatic growth arrest, and fracture malunion. This group represented 29% of patients (24 of 82) who underwent a limb lengthening procedure for a similar diagnosis during the review period. At each postoperative visit, the accuracy and precision of distraction, bone alignment, joint ROM, and any complications were recorded by the senior surgeon (SRR). Accuracy reflected how close the measured lengthening was to the prescribed distraction at each postoperative visit, while precision reflected how close the repeated measurements were to each other over the course of total lengthening period. No patients were lost to followup. Minimum followup from surgery was 3 weeks (mean, 14 weeks; range, 3–29 weeks).
Results
Mean total lengthening was 35 mm (range, 14–65 mm), with an accuracy of 96% and precision of 86%. All patients achieved target lengthening with minimal unintentional effects on bone alignment. The knee and ankle ROM were minimally affected. Of the complications requiring return to the operating room for an additional surgical procedure, there was one (4%) implant failure caused by a nonfunctional distraction mechanism and six (24%) non-implant-related complications, including premature consolidation in one patient (4%), delayed bone healing in two (8%), delayed equinus contracture in two (8%), and toe clawing in one (4%).
Conclusions
We conclude that this internal lengthening nail is a valid option to achieve accurate and precise limb lengthening to treat a variety of conditions with limb shortening or length discrepancy. Randomized, larger-sample, long-term studies are required to further confirm clinical efficacy of these devices, monitor for any late failures and complications, and compare with other internal lengthening devices with different mechanisms of operation.
Level of Evidence
Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
Bioactive glass scaffolds (70S30C; 70% SiO2 and 30% CaO) produced by a sol–gel foaming process are thought to be suitable matrices for bone tissue regeneration. Previous in vitro data showed bone ...matrix production and active remodelling in the presence of osteogenic cells. Here we report their ability to act as scaffolds for in vivo bone regeneration in a rat tibial defect model, but only when preconditioned. Pretreatment methods (dry, pre-wetted or preconditioned without blood) for the 70S30C scaffolds were compared against commercial synthetic bone grafts (NovaBone® and Actifuse®). Poor bone ingrowth was found for both dry and wetted sol–gel foams, associated with rapid increase in pH within the scaffolds. Bone ingrowth was quantified through histology and novel micro-CT image analysis. The percentage bone ingrowth into dry, wetted and preconditioned 70S30C scaffolds at 11weeks were 10±1%, 21±2% and 39±4%, respectively. Only the preconditioned sample showed above 60% material–bone contact, which was similar to that in NovaBone and Actifuse. Unlike the commercial products, preconditioned 70S30C scaffolds degraded and were replaced with new bone. The results suggest that bioactive glass compositions should be redesigned if sol–gel scaffolds are to be used without preconditioning to avoid excess calcium release.
ABSTRACT
Fast-growing broilers are especially susceptible to bone abnormalities, causing major problems for broiler producers. The cortical bones of fast-growing broilers are highly porous, which may ...lead to leg deformities. Leg problems were investigated in 6-wk-old Arkansas randombred broilers. Body weight was measured at hatch and at 6 wk. There were 8 different settings of approximately 450 eggs each. Two subpopulations, slow-growing (SG; bottom quarter, n = 511) and fast-growing (FG; top quarter, n = 545), were created from a randombred population based on their growth rate from hatch until 6 wk of age. At 6 wk of age, the broilers were processed and chilled at 4°C overnight before deboning. Shank (78.27 ± 8.06 g), drum stick (190.92 ± 16.91 g), and thigh weights (233.88 ± 22.66 g) of FG broilers were higher than those of SG broilers (54.39 ± 6.86, 135.39 ± 15.45, and 168.50 ± 21.13 g, respectivly; P < 0.001). Tibia weights (15.36 ± 2.28 g) of FG broilers were also greater than those of SG broilers (11.23 ± 1.81 g; P < 0.001). Shank length (81.50 ± 4.71 g) and tibia length (104.34 ± 4.45 mm) of FG broilers were longer than those of SG broilers (71.88 ± 4.66 and 95.98 ± 4.85 mm, respectively; P < 0.001). Shank diameter (11.59 ± 1.60 mm) and tibia diameter (8.20 ± 0.62 mm) of FG broilers were wider than those of SG broilers (9.45 ± 1.74, 6.82 ± 0.58 mm, respectively; P < 0.001). Tibia breaking strength (28.42 ± 6.37 kg) of FG broilers was higher than those of SG broiler tibia (21.81 ± 5.89 kg; P < 0.001). Tibia density and bone mineral content (0.13 ± 0.01 g/cm2 and 1.29 ± 0.23 g, respectively) of FG broilers were higher than those of SG broiler tibia (0.11 ± 0.01 g/cm2 and 0.79 ± 0.1 g; P < 0.001). Tibia percentage of ash content (39.76 ± 2.81) of FG broilers was lower than that of SG broilers (39.99 ± 2.67; P = 0.173). Fast-growing broiler bones were longer, wider, heavier, stronger, more dense, and contained more ash than SG ones. After all parameters were calculated per unit of final BW at 6 wk, tibia density and bone ash percentage of FG broilers were lower than those of SG broilers.
Innate immune cells recruited to inflammatory sites have short life spans and originate from the marrow, which is distributed throughout the long and flat bones. While bone marrow production and ...release of leukocyte increases after stroke, it is currently unknown whether its activity rises homogeneously throughout the entire hematopoietic system. To address this question, we employed spectrally resolved in vivo cell labeling in the murine skull and tibia. We show that in murine models of stroke and aseptic meningitis, skull bone marrow-derived neutrophils are more likely to migrate to the adjacent brain tissue than cells that reside in the tibia. Confocal microscopy of the skull-dura interface revealed myeloid cell migration through microscopic vascular channels crossing the inner skull cortex. These observations point to a direct local interaction between the brain and the skull bone marrow through the meninges.
Haematopoietic stem cells (HSCs) reside in a perivascular niche but the specific location of this niche remains controversial. HSCs are rare and few can be found in thin tissue sections or upon live ...imaging, making it difficult to comprehensively localize dividing and non-dividing HSCs. Here, using a green fluorescent protein (GFP) knock-in for the gene Ctnnal1 in mice (hereafter denoted as α-catulin(GFP)), we discover that α-catulin(GFP) is expressed by only 0.02% of bone marrow haematopoietic cells, including almost all HSCs. We find that approximately 30% of α-catulin-GFP(+)c-kit(+) cells give long-term multilineage reconstitution of irradiated mice, indicating that α-catulin-GFP(+)c-kit(+) cells are comparable in HSC purity to cells obtained using the best markers currently available. We optically cleared the bone marrow to perform deep confocal imaging, allowing us to image thousands of α-catulin-GFP(+)c-kit(+) cells and to digitally reconstruct large segments of bone marrow. The distribution of α-catulin-GFP(+)c-kit(+) cells indicated that HSCs were more common in central marrow than near bone surfaces, and in the diaphysis relative to the metaphysis. Nearly all HSCs contacted leptin receptor positive (Lepr(+)) and Cxcl12(high) niche cells, and approximately 85% of HSCs were within 10 μm of a sinusoidal blood vessel. Most HSCs, both dividing (Ki-67(+)) and non-dividing (Ki-67(-)), were distant from arterioles, transition zone vessels, and bone surfaces. Dividing and non-dividing HSCs thus reside mainly in perisinusoidal niches with Lepr(+)Cxcl12(high) cells throughout the bone marrow.
This study analyses the evaluation of tomographic indicators of tibia structure, assuming that the usual loading pattern shifts from uniaxial compression close to the heel to a combined compression, ...torsion and bending scheme towards the knee. To this end, pQCT scans were obtained at 5% intervals of the tibia length (S5–S95 sites from heel to knee) in healthy men and women (10/10) aged 20–40 years. Indicators of bone mass cortical area, cortical/total bone mineral content (BMC), diaphyseal design (peri/endosteal perimeters, cortical thickness, circularity, bending/torsion moments of inertia – CSMIs), and material quality (cortical vBMD (bone mineral density) were determined. The longitudinal patterns of variation of these measures were similar between genders, but male values were always higher except for cortical vBMD. Expression of BMC data as percentages of the minimal values obtained along the bone eliminated those differences. The correlative variations in cortical area, BMC and thickness, periosteal perimeter and CSMIs along the bone showed that cortical bone mass was predominantly associated with cortical thickness toward the mid‐diaphysis, and with bone diameter and CSMIs moving more proximally. Positive relationships between CSMIs (y) and total BMC (x) showed men’s values shifting to the upper‐right region of the graph and women’s values shifting to the lower‐left region. Total BMC decayed about 33% from S5 to S15 (where minimum total BMC and CSMI values and variances and maximum circularity were observed) and increased until S45, reaching the original S5 value at S40. The observed gender‐related differences reflected the natural allometric relationships. However, the data also suggested that men distribute their available cortical mass more efficiently than women. The minimum amount and variance of mass indicators and CSMIs, and the largest circularity observed at S15 reflected the assumed adaptation to compression pattern at that level. The increase in CSMIs (successively for torsion, A–P bending, and lateral bending), the decrease in circularity values and the changes in cortical thickness and periosteal perimeter toward the knee described the progressive adaptation to increasing torsion and bending stresses. In agreement with the biomechanical background, the described relationships: (i) identify the sites at which some changes in tibial stresses and diaphyseal structure take place, possibly associated with fracture incidence; (ii) allow prediction of mass indicators at any site from single determinations; (iii) establish the proportionality between the total bone mass at regions with highly predominant trabecular and cortical bone of the same individual, suitable for a specific evaluation of changes in trabecular mass; and (iv) evaluate the ability of bone tissue to self‐distribute the available cortical bone according to specific stress patterns, avoiding many anthropometric and gender‐derived influences.
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