Mean Cartilage Thickness Research Articles

Hyaline Cartilage Thickness in Radiographically Normal Cadaveric Hips: Comparison of Spiral CT Arthrographic and Macroscopic Measurements

To assess spiral multidetector computed tomographic (CT) arthrography for the depiction of cartilage thickness in hips without cartilage loss, with evaluation of anatomic slices as the reference standard. Permission to perform imaging studies in cadaveric specimens of individuals who had willed their bodies to science was obtained from the institutional review board. Two independent observers measured the femoral and acetabular hyaline cartilage thickness of 12 radiographically normal cadaveric hips (from six women and five men; age range at death, 52-98 years; mean, 76.5 years) on spiral multidetector CT arthrographic reformations and on coronal anatomic slices. Regions of cartilage loss at gross or histologic examination were excluded. CT arthrographic and anatomic measurements in the coronal plane were compared by using Bland-Altman representation and a paired t test. Differences between mean cartilage thicknesses at the points of measurement were tested by means of analysis of variance. Interobserver and intraobserver reproducibilities were determined. At CT arthrography, mean cartilage thickness ranged from 0.32 to 2.53 mm on the femoral head and from 0.95 to 3.13 mm on the acetabulum. Observers underestimated cartilage thickness in the coronal plane by 0.30 mm +/- 0.52 (mean +/- standard error) at CT arthrography (P < .001) compared with the anatomic reference standard. Ninety-five percent of the differences between CT arthrography and anatomic values ranged from -1.34 to 0.74 mm. The difference between mean cartilage thicknesses at the different measurement points was significant for coronal spiral multidetector CT arthrography and anatomic measurement of the femoral head and acetabulum and for sagittal and transverse CT arthrography of the femoral head (P < .001). Changes in cartilage thickness from the periphery to the center of the joint ("gradients") were found by means of spiral multidetector CT arthrography and anatomic measurement. Spiral multidetector CT arthrography depicts cartilage thickness gradients in radiographically normal cadaveric hips.

Quantitative and topographical evaluation of ankle articular cartilage using high resolution MRI

The objectives of this study were to quantitatively evaluate the articular cartilage layers of the ankle and describe the cartilage topographical distribution across the joint surfaces using high resolution MRI and image segmentation. An anisotropic diffusion noise reduction algorithm and a directional gradient vector flow (dGVF) snake segmentation algorithm were applied to cartilage sensitive MR images. Eight cadaveric ankles were studied. Six repeated data sets were acquired in five of the ankles. Quantitative parameters were calculated for each cartilage layer; coefficients of variation (CV) were calculated from the six repeated data sets; and 3D thickness distribution maps were generated. The noise reduction algorithm produced marked image enhancement. Mean cartilage thickness ranged from 0.91 +/- 0.08 mm in the fibula to 1.34 +/- 0.14 mm in the talus. Mean cartilage volume was 3.32 +/- 0.55 ml, 1.72 +/- 0.25 ml, and 0.35 +/- 0.06 ml for the talus, tibia, and fibula, respectively. Mean CV ranged 2.82%-5.04% for quantitative parameters in the talus and tibia. The reported noise reduction and segmentation technique allow precise extraction of ankle cartilage and 3D reconstructions show that the thickest cartilage occurs over the talar shoulders, where osteochondritits dissecans (OCD) lesions commonly occur.

Is cartilage thickness different in young subjects with and without patellofemoral pain?

To determine the differences in load-bearing patellofemoral joint cartilage thickness between genders. To determine the differences in load-bearing cartilage thickness between pain-free controls and individuals with patellofemoral pain. The articular cartilage thickness of the patella and anterior femur was estimated from magnetic resonance images in 16 young, pain-free control subjects (eight males, eight females) and 34 young individuals with patellofemoral pain (12 males, 22 females). The average age of all subjects was 28+/-4 years. The cartilage surfaces were divided into regions approximating the location of patellofemoral joint contact during knee flexion. The mean and peak cartilage thicknesses of each region were computed and compared using a repeated-measures Analysis of Variance. On average, males had 22% and 23% thicker cartilage than females in the patella (P < 0.01) and femur (P < 0.05), respectively. Male control subjects had 18% greater peak patellar cartilage thickness than males with patellofemoral pain (P < 0.05); however, we did not detect differences in patellar cartilage thickness between female control subjects and females with patellofemoral pain (P = 0.45). We detected no significant differences in femoral cartilage thickness between the control and pain groups. Thin cartilage at the patella may be one mechanism of patellofemoral pain in male subjects, but is unlikely to be a dominant factor in the development of pain in the female population.

Cartilage atrophy in the knees of patients after seven weeks of partial load bearing.

It is currently unknown whether human cartilage properties change during short periods of partial load bearing. We used a post-ankle fracture model to explore whether changes in cartilage morphology occur in the knee under conditions of partial load bearing. The knees of 20 patients with Weber type B and type C fractures were examined using magnetic resonance imaging. The first scan was obtained shortly (mean +/- SD 3.2 +/- 3.0 days) after the injury, and a second scan was obtained 7 weeks later (mean +/- SD 50.7 +/- 5.5 days). The morphology (mean and maximum thickness, volume, and surface area) of the patellar, tibial, and femoral cartilage was determined from coronal and axial magnetic resonance images (fat-suppressed gradient-echo). Between week 0 and week 7, the cross-sectional area of the quadriceps muscle was reduced by 11% (P< 0.001). Changes in the mean (+/-SD) cartilage thickness ranged from -2.9 +/- 3.2% in the patella to -6.6 +/- 4.9% in the medial tibia. No significant change in cartilage morphology of the contralateral knee was observed. Results of this study demonstrate that in a post-ankle fracture model of partial load bearing, cartilage morphology in all knee compartments is subject to significant change. Changes in the femorotibial joint exceeded those in the patella, whereas no change was observed in the contralateral knee. These findings raise the question of whether cartilage is mechanically less competent and particularly vulnerable after states of partial or complete immobilization.

Quantitative measurements of articular cartilage by magnetic resonance imaging

There is now ever-increasing acceptance that magnetic resonance imaging (MRI) can provide valuable, possibly unique, measurement data for an articular joint as a complete organ. Thus a single MRI scan, duration 10 min, which can be measured with most whole body scanners, visualises not only all the soft tissues within the joint capsule (articular cartilage, ligaments, menisci) and those surrounding it (muscles, tendons, blood vessels), but also the bone (both cortical and trabecular). Importantly, recent software developments enable quantitation of the dimensions of those structural elements. Particular attention has focused on human knee articular cartilage and a large number of studies have already reported measurement of total volumes or local volumes, and of mean cartilage thickness for an entire condyle or more localised regions. This poster will provide an overview of studies from the Herchel Smith Laboratory that demonstrate the practical realities of quantitative measurements relevant to the longitudinal studies that must be made for human drug trials. The specific questions that we have explored since 1995 include the following: • Is it best to make 'focal' or 'total' measurements? • How to enhance reproducibility of spatial relocation for serial measurements? • What are the best statistical definitions of measurement repeatability? • How to decrease interobserver variations of spatial measurements? • How to enhance measurement ergonomics? • How to automate the measurement processes?

Validation of cartilage volume and thickness measurements in the human shoulder with quantitative magnetic resonance imaging

Objective: To validate quantitative magnetic resonance imaging (qMRI) for the assessment of cartilage volume and thickness in thin and curved cartilage layers, such as the shoulder. Methods: Eight shoulder specimens from healthy individuals (aged 31–69 years) were investigated using a 3D gradient echo sequence with selective water excitation. After segmentation with a B-spline Snake algorithm, the cartilage volume and thickness were determined three dimensionally. The cartilage volume data were compared with water displacement of surgically removed tissue, and the thickness with A-mode ultrasound. Results: The glenoid and humeral head cartilage volume from qMRI agreed highly with that from water displacement (systematic difference, ±1 to ±3%; absolute difference, 4 to 7%). For the cartilage thickness, the mean systematic difference ranged from −17% (mean cartilage thickness of the glenoid) to +7% (maximal cartilage thickness of the glenoid); the standard error of the estimate was 3.7% for the humeral head, and 6.4% for the glenoid. Conclusions: The applied technique can be used for accurate determination of cartilage volume and thickness in human joints with highly curved and thin cartilage layers, such as the shoulder. In vivo application of this method will depend on the development of efficient surface coils that allow high resolution imaging under in situ conditions.

Quantitative cartilage imaging of the human hind foot: precision and inter-subject variability

Alterations of ankle cartilage are observed in degenerative and inflammatory joint disease, but cartilage cannot be directly visualized by radiography. The purpose of this study was therefore to analyze the feasibility and precision of quantitative cartilage imaging in the human hind foot (talocrural, talotarsal, and intertarsal joints), and to report the inter-subject variability for cartilage volume, thickness and surface areas. The feet of 16 healthy volunteers were imaged using a 3D gradient-echo magnetic resonance imaging sequence with water-excitation. After interpolation to a resolution of 1×0.125×0.125 mm 3 the cartilage plates were segmented, and the cartilage volume, thickness, and surface areas determined. The precision (four repeated measurements) was examined in eight volunteers, the RMS average CV% being 2.1% to 10.9% in single joint surfaces, and ⩽3% for the cumulative values of all joints. The mean cartilage thickness ranged from 0.57±0.08 (navicular surface) to 0.89±0.19 mm (trochlear surface for tibia). In conclusion this study shows that it is feasible to quantify thin cartilage layers in the hind foot under in vivo imaging conditions, and that the precision errors are substantially smaller than the inter-subject variability in healthy subjects.

Interindividual variability and correlation among morphological parameters of knee joint cartilage plates: analysis with three-dimensional MR imaging

Objective To determine the range and variability of the cartilage volume, thickness, and articular surface areas in the knee joints of healthy male subjects, the association of these parameters within and between the knee joint cartilage plates, and their correlation with anthropometric variables.Method The right knees of 27 individuals (age 23 to 64 years) without cartilage damage were examined. Sagittal magnetic resonance imaging was with a fat-suppressed gradient echo sequence (resolution 2×0.31×0.31mm3), quantitative parameters being computed for all cartilage plates.Results The total knee joint cartilage volume ranged from 16.6 to 31.4ml, the size of the articular surfaces from 102 to 163cm2, and the mean cartilage thickness from 1.57 to 2.43mm. The mean and maximal cartilage thickness were highest in the patella (2.76 and 5.72mm). There was a significant correlation of the cartilage volume with the mean thickness (R=0.80) and with the joint surface areas (R=0.56), but not between the thickness and surface area (R=0.37). The association among the patella, tibia, and femur was 0.16 to 0.72 for volumes, 0.08 to 0.78 for thickness, and 0.24 to 0.62 for surfaces. The knee joint cartilage volume and the surface areas were significantly associated with the body height (R=0.51 and 0.57), but not the cartilage thickness (R=0.22).Conclusion There is a surprisingly high variability of the quantitative distribution of cartilage within the knee joint, with only moderate correlaions between knee joint cartilage plates, and this variability cannot be adequately predicted based on anthropometric variables.

Optimization and validation of a rapid high-resolution T1-w 3D FLASH water excitation MRI sequence for the quantitative assessment of articular cartilage volume and thickness

In view of follow up, survey and development of therapeutic strategies for osteoarthritis where cartilage deterioration plays an important role, a non invasive, reliable and quantitative assessment of the articular cartilage is desirable. The currently available high resolution T1-weighted (T1-w) 3D FLASH pulse sequences with frequency selective fat suppression are very time consuming. We have 1) optimized a high resolution T1-w 3D FLASH water excitation (WE) sequence for short acquisition time and cartilage visualization, and 2) validated this sequence for cartilage volume and thickness quantification. The spectral fat presaturation was replaced by selective water excitation. The flip angle of the WE sequence was optimized for the contrast to noise (C/Ncart) ratio of cartilage. Sagittal datasets (voxel size: 0.31 × 0.31 × 2 mm3) of the knees of nine healthy volunteers were acquired both, with the 3D FLASH WE (17.2/6.6/30°) sequence (WE) and a previously validated 3D FLASH fat saturated (42/11/30°) sequence (FS). For validation of the WE sequence, cartilage volume, mean and maximal cartilage thickness of the two sequences were compared. Reproducibility was assessed by calculating the coefficient of variation (COV %) of 4 consecutive WE data sets in the volunteers. The acquisition time was reduced from 16′30″ (FS) down to 7′14″ for the WE sequence. Image contrast and visualization of the cartilage was very similar, but delineation of the basal layer of the cartilage was slightly improved with the WE sequence. A flip angle of 30° provided the best C/Ncart ratios (WE). Reproducibility (COV) was between 1.9 and 5.9%. Cartilage volume and thickness agreed within 4% between FS and WE sequence. The WE sequence allows for rapid, valid and reproducible quantification of articular cartilage volume and thickness, prerequisites for follow-up examinations. The reduced acquisition time (50% of FS) enables routine clinical application and thus may contribute to a broader assessment of osteoarthritis.

Ultrasonographic evaluation of tarsocrural joint cartilage in normal adult horses.

Ultrasonographic examination of the tarsus was performed on four clinically and radiographically normal limbs of adult horses. Particular attention was paid to the articular cartilage surfaces of the trochlear ridges of the talus and the distal intermediate ridge of the tibia. Two separate measurements of articular cartilage thickness were acquired from a longitudinal view at each site. Anatomy was confirmed with post mortem dissection. Ultrasonography was found to be a practical method for imaging the articular cartilage over the trochlear ridges of the talus and distal intermediate ridge of the tibia. The cartilage appeared as a hypoechoic band overlying the hyperechoic subchondral bone. The mean cartilage thickness over the lateral and medial trochlear ridges of the talus and the distal intermediate ridge of the tibia were 0.57 mm, 0.58 mm and 0.7 mm respectively. These measurements may have value for comparison to thickened cartilage and lesions of osteochondrosis and abnormally thinned cartilage of osteoarthritis. Ultrasound examination was not helpful in evaluating the proximal and distal intertarsal and tarsometatarsal joints, the close proximity of the articular surfaces obscured visualization of the articular cartilage.

Validation of high-resolution water-excitation magnetic resonance imaging for quantitative assessment of thin cartilage layers

Objective To employ a magnetic resonance (MR) imaging technique for quantitative assessment of thin cartilage layers, and to validate the cartilage volume and thickness measurements.Methods We investigated 10 normal elbow joints (age 20 to 69 years) with a 3D gradient echo sequence with selective water excitation (TR 18ms; TE 9ms; FA 25°, resolution 1×0.25×0.25mm2, imaging time 19min). After interpolating the image data to a 0.125×0.125mm2in-plane resolution, the cartilage plates were segmented, reconstructed in 3D, and the cartilage volume and thickness determined with a 3D Euclidean distance transformation algorithm, independent of the original section plane. The cartilage volume and thickness values were compared with CT arthrography and A-mode ultrasound.Results The mean systematic difference between the elbow cartilage volume obtained from MR imaging and CT arthrography was −0.11% (−6.0mm3) and the mean random difference 5.7% (314mm3). Except for the fovea capitis radii, the deviations were not statistically significant (range −7.6 to +11.7%). In the humerus, the mean cartilage thickness (average=1.35mm) was overestimated relative to CT arthrography (+20.7%/+0.23mm), and slightly underestimated relative to A-mode ultrasound (−6.0%/−0.05mm). With few exceptions, there were no significant differences between MRI, CT arthrography and ultrasound in the other joint surfaces of the elbow (random deviations between 0.08 and 0.39mm).Conclusions The technique presented can be applied for determining the cartilage volume and 3D thickness in joints with thin cartilage layers with a reasonable degree of accuracy.

Precision of tibial cartilage morphometry with a coronal water-excitation MR sequence.

The aim of this study was to analyze the precision of tibial cartilage morphometry, by using a fast, coronal water-excitation sequence with high spatial resolution, to compare the reproducibility of 3D thickness vs volume estimates, and to test the technique in patients with severe osteoarthritis. The tibiae of 8 healthy volunteers and 3 patients selected for total knee arthroplasty were imaged repeatedly with a water-excitation sequence (image time 6 h 19 min, resolution 1.2 x 0.31 x 0.31 mm(3)), with the knee being repositioned between each replicate acquisition. After 3D reconstruction, the cartilage volume, the mean, and the maximal tibial cartilage thickness were determined by 3D Euclidean distance transformation. In the volunteers, the precision of the volume measurements was 2.3 % (CV%) in the medial and 2.6 % in the lateral tibia. The reproducibility of the mean cartilage thickness was similar (2.6 and 2.5 %, respectively), and that of the maximal thickness lower (6.5 and 4.4 %). The patients showed a considerable reduction in volume and thickness, the precision being comparable with that in the volunteers. We find that, using a new imaging protocol and computational algorithm, it is possible to determine tibial cartilage morphometry with high precision in healthy individuals as well as in patients with osteoarthritis.

Precision MRI-based joint surface and cartilage density analysis of the knee joint using rapid water-excitation sequence and semi-automatic segmentation algorithm

The aim of this study was to analyse the precision of three-dimensional joint surface and cartilage thickness measurements in the knee, using a fast, high-resolution water-excitation sequence and a semiautomated segmentation algorithm. The knee joint of 8 healthy volunteers, aged 22 to 29 years, were examined at a resolution of 1.5 mm x 0.31 mm x 0.31 mm, with four sagittal data sets being acquired after repositioning the joint. After semiautomated segmentation with a B-spline Snake algorithm and 3D reconstruction of the patellar, femoral and tibial cartilages, the joint surface areas (triangulation), cartilage volume, and mean and maximum thickness (Euclidean distance transformation) were analysed, independently of the orientation of the sections. The precision (CV%) for the surface areas was 2.1 to 6.6%. The mean cartilage thickness and cartilage volume showed coefficients of 1.9 to 3.5% (except for the femoral condyles), the value for the medial femoral condyle being 9.1%, and for the lateral condyle 6.5%. For maximum thickness, coefficients of between 2.6 and 5.9% were found. In the present study we investigate for the first time the precision of MRI-based joint surface area measurements in the knee, and of cartilage thickness analyses in the femur. Using a selective water-excitation sequence, the acquisition time can be reduced by more than 50%. The poorer precision in the femoral condyles can be attributed to partial volume effects that occur at the edges of the joint surfaces with a sagittal image protocol. Since MRI is non-invasive, it is highly suitable for examination of healthy subjects (generation of individual finite element models, analysis of functional adaptation to mechanical stimulation, measurement of cartilage deformation in vivo) and as a diagnostic tool for follow-up, indication for therapy, and objective evaluation of new therapeutic agents in osteoarthritis.

Determination of 3D cartilage thickness data from MR imaging: Computational method and reproducibility in the living

The objective of this work was to develop a computational approach for quantifying the three-dimensional (3D) thickness distribution of articular cartilage with magnetic resonance (MR) imaging, independent of the imaging plane, and to test the reproducibility of the method in the living. An algorithm was implemented, based on a 3D Euclidean distance transformation, and its accuracy was assessed in geometric test objects, for which an analytic solution was available. The precision of the method was evaluated in six replicated MR data sets of the knee joint cartilage of eight volunteers. The algorithm produced 3D thickness values identical to those of the analytic solutions in the test objects. The reproducibility of the mean cartilage thickness in the patellar and tibial cartilages was 1.5–3.4% (root-mean-square average of the individual coefficient of variation percent), that of the maximal thickness 2.1–7.9%, and that of the thickness distribution 2.3–6.1%. The method presented allows for noninvasive analysis of 3D cartilage thickness from MR images in biomechanical and clinical investigations. Magn Reson Med 41:529–536, 1999. © 1999 Wiley-Liss, Inc.

Automatic three-dimensional reconstruction and characterization of articular cartilage from high-resolution ultrasound acquisitions

Three-dimensional (3D) high-resolution ultrasonography has proved to be useful for in vitro assessment of cartilage remodeling due to osteoarthritis. The diagnosis is performed by computation of the mean thickness of the cartilage, which reveals hypertrophy or thinning, and by 3D reconstruction of the data, which provides essential information about the size, extent, and localization of the lesion. In both cases, preliminary segmention of the cartilage is necessary. This article proposes an algorithm for automatic segmentation of the cartilage from 3D ultrasonic acquisitions of the rat patella, which includes the detection of the cartilage surface and the cartilage/bone interface. The method was designed on the assumption of regularity and smoothness of the interfaces. The use of a global threshold was sufficient to separate the patella area from the background. The cartilage/bone interface was detected by selection of regions of interest (ROIs) encompassing the interface, followed by the detection of the interface within these ROIs using the graph theory. The method was applied to 162 samples. The detection accuracy was judged to be very good or good in 99% of the cases for the cartilage surface and in 86% of the cases for the cartilage/bone interface. The mean cartilage thickness value in the central part of the patella obtained from the automatic detection method was compared to that obtained manually. The coefficient of correlation between the two measurements was 0.92. These results show that our method is reliable. Thus, fast processing of a large number of acquisitions and a more complete analysis of the cartilage surface become possible.

Nichtinvasive Analyse des Knorpelvolumens und der Knorpeldicke im menschlichen Ellbogengelenk mittels MRT

The aim of the study was to non-invasively analyse the cartilage volume and thickness in the human elbow joint with magnetic resonance imaging. 12 fresh frozen specimens (ages 20 to 69 yrs.) were investigated using a 1.5 T magnet, and a water-excitation FLASH-3D sequence at a resolution of 1 x 0.25 x 0.25 mm3. After linear interpolation to 0.125 x 0.125 mm2 in the image plane, the cartilages were segmented interactively with a Snake algorithm. Following three-dimensional reconstruction, the cartilage volumes were determined, and the mean and maximal cartilage thickness computed by Euclidean distance transformation. The total cartilage volume of the human elbow joint amounted to between 3.90 and 7.17 ml (mean 5.5 ml +/- 20%). The humerus occupied 49 to 60%, the radius 15 to 27% and the ulna 20 to 29% of the total volume. The mean cartilage thickness ranged from an average of 0.9 (proximal part of the ulna) to 1.4 mm (capitulum humeri), and the maximal thickness from 2.3 mm (proximal part of the ulna) to 2.9 mm (distal part of the ulna). The ulnar cartilage showed a more inhomogeneous distribution than that of the humerus and radius. The interindividual variability of the cartilage thickness was less than that of the volume. There was no significant relationship of the volume with age (r = 0.11) or body weight (r = 0.51). However, based on the joint size (r = 0.71-medio-lateral extension of the articular surfaces) about 50% of the variability of the total cartilage volume could be predicted. The technique presented is suitable for designing computer models to investigate the load transmission and functional adaptation of diarthrodial joints, and for diagnosing and monitoring joint disease.

Computer-aided three dimensional assessment of knee-joint cartilage with magnetic resonance imaging

Objective. An MRI-based technique for non-invasive assessment of the quantitative distribution of articular cartilage in the knee-joint was to be developed, and its accuracy and reproducibility tested.Design. Three cadaveric specimens and one patient were studied and MRI measurements compared with anatomical sections or arthroscopy.Background. Data on articular cartilage thickness is needed for the design of computer models, determination of cartilage material properties from arthroscopy and staging of osteoarthrosis.Methods. The knees were imaged using strongly T2-weighted spin-echo and FISP-3D sequences. After digital subtraction and automatic segmentation, three-dimensional reconstruction of the cartilages was performed. Surface areas, volumes and the mean cartilage thickness were calculated, and the regional distribution displayed after trigonometric correction.Results. The difference between MRI volumes and those obtained from the sections ranged from 4 to 21% with a reproducibility of ±4 to ±12% after repositioning. The thickness maps obtained with MRI were very similar to those from the sections. In the patient, a full-thickness defect demonstrated with MRI was verified by arthroscopy.Conclusions. Using the technique presented, the quantitative distribution of knee-joint cartilage may be analysed non-invasively, accurately, and in a very time-effective manner, in cadavers and in living subjects.

The potential of magnetic resonance imaging (MRI) for quantifying articular carrtilage thickness—a methodological study

The thickness of patellar articular cartilage was assessed in a cadaveric human knee joint by magnetic resonance imaging. Imaging was conducted at 1.0 T, using three-dimensional gradient-echo sequences. From each of the sequences the total cartilage volume, the size of the articular surface, the mean cartilage thickness and the regional distribution of cartilage thickness were determined by image analysis. These values were then compared with those obtained from anatomical sections. The fat-suppressed flash sequence was found to allow the most accurate evaluation of the total volume and the regional distribution of the articular cartilage. Slight underestimation of the cartilage thickness by about 5% may be due to the fact that the calcified layer is not made visible by magnetic resonance imaging. There is, however, a very high degree of similarity between the distribution patterns obtained from the MR images and the anatomical sections. The contrast-to-noise ratios and reproducibility were also highest with the fat-suppressed flash sequence. This pulse sequence can therefore be recommended for experimental and clinical use.

Chondrogenesis by Free and Vascularized Rabbit Auricular Perichondrium

Many qualitative studies examining the chondrogenic potential of perichondrium have suggested that it may be useful for airway reconstruction. This study was performed to quantitatively evaluate cartilage formation by free and vascularized rabbit perichondrium placed in sterile and contaminated (airway) environments for 8 weeks. The mean cartilage thickness for free sterile perichondrium was 0.09 mm, for free contaminated perichondrium was 0.13 mm, for vascularized sterile perichondrium was 0.16 mm, and for vascularized contaminated perichondrium was 0.44 mm. Contaminated vascularized grafts produced significantly more cartilage when compared to both sterile vascularized grafts (p = .001) and contaminated free grafts (p < .001). No differences in cartilage formation were seen between sterile and contaminated free grafts (p = .198), or between free and vascularized grafts that were sterile (p = .170). These findings support further investigation of airway reconstruction with vascularized perichondrial grafts.

Comparison of the Chondrogenic Potential of Free and Vascularized Perichondrium in the Airway

Revascularized perichondrium or periosteum may be the ideal graft to repair severe laryngotracheal stenosis because of its pliability, potential for bone or cartilage formation, resistance to infection, and rapid mucosalization. To begin our evaluation of these grafts in airway reconstruction, this study was designed to quantify the chondrogenic capacity of free and vascularized perichondrium placed in the airway. In a rabbit model, free auricular perichondrium (N = 16) produced a mean cartilage thickness of 0.15 mm, whereas vascularized auricular perichondrium (N = 18) produced a mean of 0.45 mm at 8 weeks (p < .0001). In a third group of rabbits (N = 4) vascularized auricular perichondrial grafts were subjected to a 2-hour intraoperative ischemic insult in order to simulate the ischemia of revascularization. The mean cartilage thickness at 8 weeks was 0.50 mm. We conclude that in the rabbit model, vascularized perichondrium provides significantly more cartilage than free perichondrial grafts.