Surface Of Condyle Research Articles

Incidence of Medial Plica in 3,889 Knee Joints in the Japanese Population

This study aimed to document the incidence of medial plicae (plica synovialis mediopatellaris) in a large sample of the Japanese population and classify them in a type-dependent manner. The incidence of medial plicae was investigated during arthroscopic surgery of 3,889 knee joints in 3,563 patients (mean age, 35 years); medial plicae were classified according to Sakakibara's classification (type A, a cord-like elevation in the synovial wall; type B, a shelf-like appearance; type C, a large shelf-like appearance covering the anterior surface of the medial femoral condyle; and type D, double insertions into the medial wall or having a central defect). Of all the knee joints examined, 2,006 knees belonged to male patients and 1,883 to female patients. Both knee joints were examined in 326 patients. From these data, the incidence of medial plicae was calculated. The overall incidence rate of medial plicae was 79.9%. The incidence of Sakakibara type A, B, C, and D medial plicae was 35.2%, 22.4%, 12.3%, and 10.0%, respectively. This pattern was reflected in all age groups in both genders, except in women aged 20 to 39 years. The κ coefficient was moderate, at 0.407, in the patients in whom both knee joints were examined. In a large cohort of Japanese patients undergoing arthroscopic knee surgery, the incidence of medial plica was 79.9%. The same pattern was seen in almost all age groups and in both genders (type A > type B > type C > type D). Level IV, prognostic case series.

Treatment Outcomes of Alginate-Embedded Allogenic Mesenchymal Stem Cells Versus Autologous Chondrocytes for the Repair of Focal Articular Cartilage Defects in a Rabbit Model

Background: Mesenchymal stem cells (MSCs) represent a promising alternative form of cell-based therapy for cartilage injury. However, the capacity of MSCs for chondrogenesis has not been fully explored. In particular, there is presently a lack of studies comparing the effectiveness of MSCs to conventional autologous chondrocyte (autoC) treatment for regeneration of full-thickness cartilage defects in vivo. Hypothesis: Treatment with allogenic undifferentiated MSCs (alloMSCs) results in superior cartilage tissue regeneration profiles when compared with autoC for repair of focal articular cartilage defects. Study Design: Controlled laboratory study. Methods: Full-thickness articular cartilage defects were created on the weightbearing surface of the medial femoral condyles in both knees of New Zealand White rabbits (N = 30). Six weeks after the defect was induced, the right knee was treated with either alloMSCs (n = 12) or autoC (n = 18), while the left knee remained untreated (control). The rabbits were sacrificed at 6 months after treatment for assessment of cartilage tissue regeneration, which included the Brittberg morphologic score, histologic grading by O’Driscoll score, and quantitative analysis of glycosaminoglycans per total protein content. Results: Apart from significantly higher Brittberg scores in the alloMSC treatment group (8.8 ± 0.8) versus the autoC treatment group (6.6 ± 0.8) (P = .04), both treatments showed similar cartilage regenerative profiles. All outcome measures were significantly higher in the treatment groups compared with their respective controls (P < .05). Conclusion: AlloMSCs have similar effectiveness as autoC for repair of focal cartilage defects. Both treatments resulted in superior tissue regeneration compared with untreated defects. Clinical Relevance: The results have an implication of supporting the potential use of MSCs for cartilage repair after sports injuries or diseases, in view of similar efficacy but less patient morbidity and potential cost savings as compared with conventional autoC therapy.

Effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee

To evaluate the effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee. The subjects were 40 patients who had undergone autologous osteochondral grafting. Fifteen knees had cartilage defects combined with anterior cruciate ligament tears (ACL group), 15 knees had cartilage defects combined with osteoarthritis (OA group), and 10 knees had cartilage defects combined with osteochondral dissecans (OCD group). From one to five osteochondral pegs were harvested from the less-weight-bearing periphery of the articular surface of the femoral condyle and grafted to cartilage defects. The clinical results were assessed based on the Lysholm score and radiographic and magnetic resonance imaging (MRI) image assessment. The median follow-up duration was 24months (range from 12 to 41months). The mean Lysholm score following treatment was improved in all groups. The patients who had cartilage defects combined with OA had a significantly poorer prognosis than did those with cartilage defects combined with ACL or OCD. In the OA group, advanced stage and an alignment abnormality were correlated with poor prognosis. Advanced age was correlated with poor prognosis. Other parameters showed no significant difference in prognosis. Autologous osteochondral grafting was found to be an effective technique for treating relatively young patients who had cartilage defects combined with ACL injury or OCD, but this technique showed limited results in treating cartilage defects based on advanced patient age and degenerative changes in the cartilage. Diagnostic studies-investigating a diagnostic test, Level III.

SOX Trio Decrease in the Articular Cartilage with the Advancement of Osteoarthritis

SOX trio (SOX-5, SOX-6, and SOX-9) maintain the chondrocytic phenotypes and are vital for chondrogenesis in embryonic development. The purpose of this study is to investigate the change in the expression of SOX trio with the advancement of osteoarthritis (OA) in human articular cartilage (AC). Human OA samples from eight patients were obtained from the distal femoral condyles during total knee arthroplasty. Minimally OA cartilage taken from areas with no obvious surface defects on lateral condyles was compared with advanced OA cartilage obtained from areas within 1 cm of overt lesion located on medial condyle surface. SOX-5, SOX-6, and SOX-9 gene expressions significantly decreased by 41% (p = 0.047), 46% (p = 0.047), and 56% (p = 0.029) in advanced OA area compared with the minimally OA area. There was a significant decrease in aggrecan and type II collagen (COL2A1) gene expressions by 73% (p = 0.029) and 65% (p = 0.029), respectively, in advanced OA area compared with the minimally OA area. From Western blotting and immunohistochemistry, SOX-5, SOX-6, SOX-9, type II collagen, and aggrecan protein expressions also significantly decreased in advanced OA cartilage compared with minimally OA cartilage. DNA methylation study of SOX-9 promoter regions revealed no difference in the epigenetic status between the two areas. It is concluded that SOX trio gene and protein decreased with advancement of OA in human articular cartilage.

MR imaging and anatomic study of articular cartilage of the knee joint

Objective To compare corpse sampling and MR imaging with 3D-FS-SPGR sequences in measurement of the articular cartilage thickness and to investigate knee cartilage topography. Methods Two fresh specimens of the knee joint were obtained from 2 normal young adult male corpses of medium stature. MR1 scanning was carried on the 2 specimens in sagittal 3D-FS-SPGR MR sequences. After defrosted,the knee specimens were dissected longitudinally, and the cartilage thicknesses were measured at different locations of the knee joint. Paraffin sections of the knee cartilage were observed following compound staining with victoria blue and ponceau red. Results The average cartilage thicknesses measured by dissection and MR imaging sequence were respectively: 2. 25 mm and 2. 25 mm at the anterior weight-loading surface of the femoral lateral condyle, 2. 70 mm and 2. 75 mm at the posterior weight-loading surface of the femoral lateral condyle, 2. 00 mm and 2. 10 mm at the anterior weight-loading surface of the tibial lateral condyle,2. 35 mm and 2. 25 mm at the posterior weight-loading surface of the tibial lateral condyle, 2. 20 mm and 2. 20mm at the anterior weight-loading surface of the femoral medial condyle, 2. 15 mm and 2. 30 mm al the posterior weight-loading surface of the femoral medial condyle, 2. 20 mm and 2.45 mm at the anterior weight-loading surface of the tibial medial condyle, 2. 70 mm and 2. 95 mm at the posterior weight-loading surface of the tibial medial condyle and 3. 08 mm and 3. 15 mm at patella cartilage surface. Collagen fibers were rich at the periphery of the articular cartilage with sparse chondrocytes and matrixes, while the opposite was observed at the center of the articular cartilage. Conclusions MR imaging with 3D-FS-SPGR sequences can display the actual knee cartilage topography. Collagen fibers mainly concentrate at the periphery of the articular cartilage, which accounts for the function of the articular cartilage. Key words: Knee joint; Cartilage, articular; Magnetic resonance imaging; Anatomy, cross section

Effect of Low-Intensity Pulsed Ultrasound on MMP-13 and MAPKs Signaling Pathway in Rabbit Knee Osteoarthritis

We evaluated the effect of low-intensity pulsed ultrasound (LIPUS) on MMP-13 and MAPKs expression in rabbit knee osteoarthritis (OA). For this purpose, 18 New Zealand white rabbits were randomly and equally divided into O + L, O - L, and SO groups. In O + L group, animals underwent right back leg ACLT operation and LIPUS radiation. In O - L group, animals underwent ACLT but no LIPUS treatment. In SO (control) group, animals underwent sham operation without LIPUS. After 6 weeks, we assessed the pathologic changes in the articular surface of femoral condyle and compared using Mankin scores. Also, expression of type-II collagen, MMP-13, ERK1/2, p38, and JNK was measured by Western blot. Compared with controls, Mankin scores were higher in O + L (P < 0.05)/O - L (P < 0.01) groups. Compared with O + L group, score was higher in O - L group (P < 0.05). Compared with controls, type-II collagen expression was less in O + L/O - L groups, with more significant decrease in O - L group (P < 0.05). Contrarily, expression of MMP-13, p-ERK1/2, and p-p38 was enhanced in O + L/O - L groups as compared with controls, with more significant increase in O - L group (P < 0.01). Compared with O + L group, expression was higher in O - L group (P < 0.05). We, therefore, concluded that LIPUS application promoted cartilage repair in OA through the downregulation of MMP-13, ERK1/2, and p38.

Posterior Condyle Surface Damage on Retrieved Femoral Knee Components

Twenty-two retrieved femoral knee components were identified with posterior condyle surface damage on average at 99° flexion (range, 43°-135° flexion). Titanium alloy material transfer and abrasive surface damage were evident on cobalt-chromium alloy femoral components that were in contact with titanium alloy tibial trays. Surface damage on the retrieved Oxinium femoral components (Smith and Nephew, Inc, Memphis, Tenn) that were in contact with titanium alloy tibial trays showed gouging, associated with the removal and cracking of the oxide and exposure of the zirconium-niobium alloy substrate. Cobalt-chromium alloy femoral components that were in contact with cobalt-chromium alloy tibial trays showed abrasive wear. Contact between the femoral component and tibial tray should be avoided to prevent surface damage to the femoral condyles, which could potentially accelerate polyethylene wear in vivo.

A Moderate-Intensity Static Magnetic Field Enhances Repair of Cartilage Damage in Rabbits

Electromagnetic fields have been proposed to enhance healing of cartilage defects by stimulation of chondrocyte proliferation, proteoglycan synthesis as well as decreasing pain and improving motion in osteoarthritic patients. However, the effects of a moderate-intensity static magnetic field on cartilage repair have not been investigated. This study tries to determine the effects of a moderate-intensity permanent magnetic field of 40 mT on cartilage repair. Defects of 3 mm in diameter and 6 mm in depth were made on the weight bearing surface of the right medial femoral condyle of 30 rabbits. The animals were divided randomly into three equal groups (magnet, sham and control). In the magnet group, cylindrical permanent magnets were implanted subcutaneously medial to the medial femoral condyle, while in the sham group the cylindrical ceramic were not magnetized, and nothing was implanted in controls. After 12 weeks of observation, Mankin's microscopic scoring was done on all specimens, and irregularity of surface characteristics, cell colonization, hypocellularity, cartilage matrix formation, and presence of empty lacunae were investigated. Each of these characteristics showed significant differences in magnet group relative to control and sham groups (p <0.05). Mankin's score was 1.6 ± 0.6 in magnet group, 7.2 ± 1.6 in sham group and 7.7 ± 1 in control group (p <0.001). [corrected] In this animal study, microscopic Mankin's scoring depicted histological improvement in cartilage of magnet group.

Geometric mismatch analysis of retrograde nail in the Asian femur

The geometric mismatch analysis of the retrograde nail was performed in 108 Asian cadaveric adult femora. The insertion was done virtually based on a three-dimensional geometric model derived from computed tomographic images. The investigation was performed at eight levels located at 120, 140, 160, 180, 200, 220 and 240 mm above the condylar surface. The evaluation of each level included: (1) the diameter of the intramedullary canal, (2) the percentage of area filled by the nail in the unreamed intramedullary canal, (3) the minimal reamer diameter that required enlargement of the canal to accommodate retrograde nail insertion, (4) the minimal inner cortical reaming thickness that needed to be removed, (5) the percentage of the cortical bone area that needed to be removed prior to nail insertion and (6) the deviation of the nail center from the center of the intramedullary canal. The result showed significant mismatch of the nail to most of the study specimens (94 femora, 87%), which the intramedullary canal needed extensive reaming to accommodate the nail insertion. This may lead to a high possibility of clinical complications. Redesign for proper shape and size of retrograde nail should be considered for the use in Asian population.

Superficial zone protein affects boundary lubrication on the surface of mandibular condylar cartilage

We examined the localization and boundary lubricating function of superficial zone protein (SZP) on the surface of mandibular condylar cartilage. Chondrocytes were separated from the surface layer of mandibular condylar cartilage of 6- to 9-month-old female pigs. A cyclic tensile strain of 7% or 21% cell elongation was applied to the cultured chondrocytes. Gene expression levels of cartilage matrix proteins and secretory phospholipase A(2) (sPLA(2)) were quantified by real-time polymerase chain reaction analysis. The friction coefficient of the mandibular condylar surface was measured by a friction tester before and after treatment with 0.1 U/ml sPLA(2). Significantly higher mRNA levels of SZP and type I collagen were found in chondrocytes from the superficial layer than in those in the other layers. The SZP mRNA level was up-regulated by cyclic tensile strain of 7% and 21% cell elongation. Cyclic tensile strain of 21% cell elongation up-regulated the sPLA(2) mRNA level. The friction coefficient of the condylar surface was increased significantly by treatment with sPLA(2). The removal of SZP from the surface layer of mandibular condylar cartilage by sPLA(2) resulted in a significant increase in the friction coefficient on the surface of articular cartilage.

Distribution features of surface stress on the bilateral condyles of the unilateral mandible model for 3 kinds of surgeries of temporomandibular joint ankylosis

To determine the distribution features of surface stress on the bilateral condyles of the normal mandible and the unilateral mandible model for 3 kinds of surgeries of temporomandibular joint ankylosis under normal occlusal strength. The normal mandible 3-dimensional finite element model and the 3-dimensional finite element mandible model for 3 kinds of surgeries of unilateral temporomandibular joint ankylosis were built. The jaw triangle area and the condyle transverse ridge was fixed and bound at mid-point. And 100 N of load was applied to the first molars of the bilateral mandible to obtain a von Mises stress diagram of the condylar surface and the unit von Mises stress of the condylar surface. Statistical analysis was carried out. The transmission of von Mises stress at the operated side of fractured articular arthroplasty of the condylar was interrupted. The von Mises stress at the operated side of the condylar in the group of point-surface contact joint reconstruction was bigger than that of the normal group (P<0.05) whereas there was no significant difference between the group of surface-surface contact joint reconstruction group and the normal group (P>0.05). The von Mises stress of the condylar at the non-operated side in the group of fractured articular arthroplasty was bigger than that of the normal group (P<0.05), whereas there was no significant difference between the group of point-surface contact or surface-surface contact group and the normal group (P>0.05). The surface-surface articular reconstruction is beneficial to the recovery of the masticatory function without increasing the burden for contralateral temporomandibular joint and is helpful to the joint. Thus this surgical method is recommended.

Temporomandibular Joint Synovial Chondromatosis With Intracranial Extension: A Review and Observations of Patient Observed for 4 Years

The diagnosis is from the imaging and histologicfindings. The differential diagnosis includes osteoma,osteoblastoma, osteochondroma, condylar hyperpla-sia, chondroblastoma, chondrosarcoma, and osteosar-coma. The radiologic features of TMJ SC are nonspe-cific but can include calcified loose bodies, soft tissueswelling, widening of the joint space, alterations tothe joint surface, and sclerosis or hyperostosis of theglenoid fossa and/or mandibular condyle.

The expression of SP and CGRP in the temporomandibular joints of the rats undergone emotional stress

Objective To observe the substance P(SP) and calcitonin gene-related peptide(CGRP) expressions in the temporomandibular joints(TM J) of the rats undergone emotional stress and explore the relationship between emotional stress and temporomandibular joint disorder(TMD). Methods Ninety SD rats were averagely randomly divided into emotional stress ( ES ) group( n = 30 ), electric foot-shocked (FS) group ( n = 30 ) and control (CON) group( n = 30). The emotional stress was induced by communication box. The TMJ tissues in ES and CON groups were removed after 1, 3 and 5 weeks of emotional stress for scanning electron microscope ( SEM ) test and immunohistochemistry test. The SP and CGRP expressions were examined with SABC immunohistochemistry and then analyzed by image analysis system. Results The expressions of SP and CGRP had significant difference after 1 ,3 and 5 weeks emotional stress ( SP: 124.5 ± 16.9,185.6 ± 1.8 and 193.5 ± 3.5, respectively; CGRP: 185.9 ±5.3, 112.5 ±5.2 and 174.3 ±5.3 ,respectively) (P＜0. 05 ). The SEM results showed that there was a series of structural change on the condylar surface after emotional stress. Conclusion The SP and CGRP energy nerve fibers take part in the TMJ pathological process undergone emotional stress. Key words: Substance P; Calcitonin gene related peptide; Temporomandibular joint; Emotional stress

Repair of articular cartilage defects with tissue-engineered osteochondral composites in pigs

To compare the results of repair of knee cartilage defects with tissue-engineered osteochondral composites and tissue-engineered cartilage in pigs. Autologous chondrocytes and osteoblasts were seeded on scaffolds of polylactic-co-glycolic acid (PLGA) and tricalcium phosphate (TCP) to generate tissue-engineered cartilage and tissue-engineered bone, respectively. The tissue-engineered osteochondral composite was formed by a chondrocyte-PLGA construct sutured to an osteoblast-TCP construct with an absorbable suture. Cartilage defects were surgically created at the weightbearing surface of the bilateral femoral medial condyles of 12 mini-pigs. Thus, 24 defects in 12 pigs were randomly assigned to three treatment groups: tissue-engineered osteochondral composite group, tissue-engineered cartilage group, and blank control group. Six months after surgery, the regenerated cartilage was scored macroscopically and histologically. The compressive properties and glycosaminoglycan (GAG) content of the cartilage were also assessed. The gross grading scale indicated that the mean scores of the tissue-engineered osteochondral composite group were significantly higher than those of the tissue-engineered cartilage group. According to the International Cartilage Repair Society (ICRS) Visual Histological Assessment Scale, the scores of the osteochondral composite group were significantly better than those of the tissue-engineered cartilage group and blank control group. Assessment of compressive properties and GAG content showed better repair results in the osteochondral composite group than those of the tissue-engineered cartilage group. Using tissue-engineered osteochondral composites to repair cartilage defects was better than that of tissue-engineered cartilage.

Condylar volume and surface in Caucasian young adult subjects

BackgroundThere have been no quantitative standards for volumetric and surface measurements of the mandibular condyle in Caucasian population. However, the recently developed cone-beam computed tomography (CBCT) system allows measurement of these parameters with high accuracy.MethodsCBCT was used to measure the condylar volume, surface and the volume to surface ratio, called the Morphometric Index (MI), of 300 temporo-mandibular joints (TMJ) in 150 Caucasian young adult subjects, with varied malocclusions, without pain or dysfunction of TMJs.ResultsThe condylar volume was 691.26 ± 54.52 mm3 in males and 669.65 ± 58.80 mm3 in, and was significantly higher (p< 0.001) in the males. The same was observed for the condylar surface, although without statistical significance (406.02 ± 55.22 mm2 in males and 394.77 ± 60.73 mm2 in females).Furthermore, the condylar volume (693.61 ± 62.82 mm3 ) in the right TMJ was significantly higher than in the left (666.99 ± 48.67 mm3, p < 0.001) as was the condylar surface (411.24 ± 57.99 mm2 in the right TMJ and 389.41 ± 56.63 mm2 in the left TMJ; t = 3.29; p < 0.01). The MI is 1.72 ± 0.17 for the whole sample, with no significant difference between males and females or the right and left sides.ConclusionThese data from temporomandibular joints of patients without pain or clinical dysfunction might serve as examples of normal TMJ's in the general population not seeking orthodontic care.

INTRAJOINT OSTEOTOMIES FOR POSTTRAUMATIC DEFORMITIES OF TIBIAL CONDYLAR SURFACES

Twenty two patients were operated on account of joint surface deformities developed due to malunion of healed tibial condylar impressions. The peculiarity of operation was the osteotomy line, which contoured the perimeter of impression to mobilize it, and after that the fragments were plated with bone grafting. Early function is essential. We met one deep infection. The late follow-up was generally positive. The intrajoint osteotomies can effectively restore posttraumatic deformities of tibial condylar surface and normalize the anatomy with good function and low pain. This operation optimizes anatomic and functional conditions for probable joint replacement and is able to delay the need in it at least for decade and for thus decrease the problems of revisions.

Chondrogenic effect of the perichondrium graft on the internal derangement and osteoarthritis of the temporomandibular joint of the rabbit

Internal derangement of the temporomandibular joint is usually defined as the disruption of the condyle and disc relationship. In addition to this description the other elements of the joint including the cartilage surface, synovial fluid, the ligaments and the bony surface itself demonstrate varying degrees of pathology in concordance with the stage of the internal derangement, as well. This study is designed to create an osteoarthritic model in the rabbit temporomandibular joint. A 2 × 2 mm defect was performed on the cartilage surface of the both condyles of each animal ( n = 30). The osteoarthritic changes were demonstrated by computerised tomography sections. The right joints of the animals constituted the control group and the left, the study group. At the time of the defect generation, a perichondrium graft from the animal’s ear was implanted onto the defect in the study group. The control group was left to heal secondarily. The joints of three randomized groups of 10 animals for each were inspected at the 4th, 6th, and 8th weeks. Cartilage regeneration and regression of the osteoarthritic changes were demonstrated in the study group both in the 6th and 8th week groups. However, the control group showed less cartilage regeneration and progression of the osteoarthritic changes in all weeks, with progression with time. The perichondrium graft has demonstrated chondrogenic effect on the condyle and this in turn changed the progression to internal derangement.

Anatomical Study of the Radius and Center of Curvature of the Distal Femoral Condyle

In this anatomical study, the anteroposterior curvature of the surface of 16 cadaveric distal femurs was examined in terms of radii and center point. Those two parameters attract high interest due to their significance for total knee arthroplasty. Basically, two different conclusions have been drawn in foregoing studies: (1) The curvature shows a constant radius and (2) the curvature shows a variable radius. The investigations were based on a new method combining three-dimensional laser-scanning and planar geometrical analyses. This method is aimed at providing high accuracy and high local resolution. The high-precision laser scanning enables the exact reproduction of the distal femurs-including their cartilage tissue-as a three-dimensional computer model. The surface curvature was investigated on intersection planes that were oriented perpendicularly to the surgical epicondylar line. Three planes were placed at the central part of each condyle. The intersection of either plane with the femur model was approximated with the help of a b-spline, yielding three b-splines on each condyle. The radii and center points of the circles, approximating the local curvature of the b-splines, were then evaluated. The results from all three b-splines were averaged in order to increase the reliability of the method. The results show the variation in the surface curvatures of the investigated samples of condyles. These variations are expressed in the pattern of the center points and the radii of the curvatures. The standard deviations of the radii for a 90 deg arc on the posterior condyle range from 0.6 mm up to 5.1 mm, with an average of 2.4 mm laterally and 2.2 mm medially. No correlation was found between the curvature of the lateral and medial condyles. Within the range of the investigated 16 samples, the conclusion can be drawn that the condyle surface curvature is not constant and different for all specimens when viewed along the surgical epicondylar axis. For the portion of the condylar surface that articulates with the tibia during knee flexion-extension, the determined center points approximate the location of the centers of rotation. The results suggest that the concept of a fixed flexion-extension axis is not applicable for every specimen.

Regeneration of the articular surface of the rabbit synovial joint by cell homing: a proof of concept study

A common approach for tissue regeneration is cell delivery, for example by direct transplantation of stem or progenitor cells. An alternative, by recruitment of endogenous cells, needs experimental evidence. We tested the hypothesis that the articular surface of the synovial joint can regenerate with a biological cue spatially embedded in an anatomically correct bioscaffold. In this proof of concept study, the surface morphology of a rabbit proximal humeral joint was captured with laser scanning and reconstructed by computer-aided design. We fabricated an anatomically correct bioscaffold using a composite of poly-epsilon-caprolactone and hydroxyapatite. The entire articular surface of unilateral proximal humeral condyles of skeletally mature rabbits was surgically excised and replaced with bioscaffolds spatially infused with transforming growth factor beta3 (TGFbeta3)-adsorbed or TGFbeta3-free collagen hydrogel. Locomotion and weightbearing were assessed 1-2, 3-4, and 5-8 weeks after surgery. At 4 months, regenerated cartilage samples were retrieved from in vivo and assessed for surface fissure, thickness, density, chondrocyte numbers, collagen type II and aggrecan, and mechanical properties. Ten rabbits received TGFbeta3-infused bioscaffolds, ten received TGFbeta3-free bioscaffolds, and three rabbits underwent humeral-head excision without bioscaffold replacement. All animals in the TGFbeta3-delivery group fully resumed weightbearing and locomotion 3-4 weeks after surgery, more consistently than those in the TGFbeta3-free group. Defect-only rabbits limped at all times. 4 months after surgery, TGFbeta3-infused bioscaffolds were fully covered with hyaline cartilage in the articular surface. TGFbeta3-free bioscaffolds had only isolated cartilage formation, and no cartilage formation occurred in defect-only rabbits. TGFbeta3 delivery yielded uniformly distributed chondrocytes in a matrix with collagen type II and aggrecan and had significantly greater thickness (p=0.044) and density (p<0.0001) than did cartilage formed without TGFbeta3. Compressive and shear properties of TGFbeta3-mediated articular cartilage did not differ from those of native articular cartilage, and were significantly greater than those of cartilage formed without TGFbeta3. Regenerated cartilage was avascular and integrated with regenerated subchondral bone that had well defined blood vessels. TGFbeta3 delivery recruited roughly 130% more cells in the regenerated articular cartilage than did spontaneous cell migration without TGFbeta3. Our findings suggest that the entire articular surface of the synovial joint can regenerate without cell transplantation. Regeneration of complex tissues is probable by homing of endogenous cells, as exemplified by stratified avascular cartilage and vascularised bone. Whether cell homing acts as an adjunctive or alternative approach of cell delivery for regeneration of tissues with different organisational complexity warrants further investigation. New York State Stem Cell Science; US National Institutes of Health.

Nonanatomic Tunnel Position in Traditional Transtibial Single-Bundle Anterior Cruciate Ligament Reconstruction Evaluated by Three-Dimensional Computed Tomography

Transtibial drilling techniques are widely used for arthroscopic reconstruction of the anterior cruciate ligament, most likely because they simplify femoral tunnel placement and reduce surgical time. Recently, however, there has been concern that this technique results in nonanatomically positioned bone tunnels, which may cause abnormal knee function. The purpose of this study was to use three-dimensional computed tomography models to visualize and quantify the positions of femoral and tibial tunnels in patients who underwent traditional transtibial single-bundle reconstruction of the anterior cruciate ligament and to compare these positions with reference data on anatomical tunnel positions. Computed tomography scans were performed on thirty-two knees that had undergone transtibial single-bundle reconstruction of the anterior cruciate ligament. Three-dimensional computed tomography models were aligned into an anatomical coordinate system. Tibial tunnel aperture centers were measured in the anterior-to-posterior and medial-to-lateral directions on the tibial plateau. Femoral tunnel aperture centers were measured in anatomic posterior-to-anterior and proximal-to-distal directions and with the quadrant method. These measurements were compared with reference data on anatomical tunnel positions. Tibial tunnels were located at a mean (and standard deviation) of 48.0% +/- 5.5% of the anterior-to-posterior plateau depth and a mean of 47.8% +/- 2.4% of the medial-to-lateral plateau width. Femoral tunnels were measured at a mean of 54.3% +/- 8.3% in the anatomic posterior-to-anterior direction and at a mean of 41.1% +/- 10.3% in the proximal-to-distal direction. With the quadrant method, femoral tunnels were measured at a mean of 37.2% +/- 5.5% from the proximal condylar surface (parallel to the Blumensaat line) and at a mean of 11.3% +/- 6.6% from the notch roof (perpendicular to the Blumensaat line). Tibial tunnels were positioned medial to the anatomic posterolateral position (p < 0.001). Femoral tunnels were positioned anterior to both anteromedial and posterolateral anatomic tunnel locations (p < 0.001 for both). Transtibial anterior cruciate ligament reconstruction failed to accurately place femoral and tibial tunnels within the native anterior cruciate ligament insertion site. If anatomical graft placement is desired, transtibial techniques should be performed only after careful identification of the native insertions. If anatomical positioning of the femoral tunnel cannot be achieved, then an alternative approach may be indicated.