Subchondral Area Research Articles

Pain in Anterior Knee after Locked Nailing of Diaphyseal Tibia Fractures

The relevance of the study is determined by the high incidence of pain in the anterior knee after the locked nailing of the diaphyseal tibia fracture. The etiology and pathogenesis of this complication remain unclear. Most authors believe that the cause of this complication is a combination of several factors. Material and Methods. The study included 70 patients with consolidated diaphyseal tibia fractures undergone closed blocked nailing through the patellofemoral ligament. The results of the surgery were studied in the time frame of 2 to 4 years (average 36.96±12.05 months). Patients were divided into groups according to the presence or absence of pain in the anterior knee, the type of tibial fractures, the location of the nail in the proximal tibia metaphysis. The evaluation of the outcomes was carried out with the SF-36 questionnaire and the knee X-ray. The significance of differences in the samples was determined by the Pearson’s and Student’s criteria, and Fisher’s exact criterion. Results. The incidence of pain in the anterior knee was 46%. This complication led to a decrease in the patients’ quality of life to a greater extent and in most parameters than in the patient without pain, namely, physical components of health by 10% (p = 0.024), physical activity by 8.8% (p = 0.024), role-based functioning due to physical condition by 14.1% (p = 0.001). The intergroup analysis revealed that the extension of the end of the nail beyond the proximal tibial metaphysis was one of the factors that determeded the development the pain (p0.05). There were differences in the frequency of pain in groups with different depths of immersion of the nail into the proximal metaphysis (p0.05). The closer to the tibial plateau the proximal end of the nail was located, the more often the pain occurred in the postoperative period. In the patients with type C diaphyseal fractures, pain in the knee was much more common than in patients with type A and B fractures (p0.05). Conclusion. The quality of life of the patients with pain in the anterior knee after locked nailing was characterized by a decrease in physical activity and role functioning in society. The main cause of the pain was the projection of the nail beyond the bone borders of the tibial metaphysis or the location of its proximal end in the subchondral area. The type of diaphyseal tibia fracture according to the AO / ASIF classification was a factor that determined the incidence of pain in the anterior knee.

REMODELING OF THE TEMPROMANDIBULAR JOINT FOLLOWING DIFFERENT RATES OF MANDIBULAR DISTRACTION OSTEOGENESIS (AN EXPERIMENTAL STUDY)

Introduction: patients with craniofacial deformities resulting from trauma, infection, tumors and congenital defects usually require skeletal expansion. Tradition treatment methods, involve autogenous bone grafting, which often results in problems including graft resorption, infection and donor site morbidity. Distraction osteogenesis has been adopted more and can help overcome these problems. Aim of the work: the purpose of this study was to compare histologically the effect of bilateral distraction osteogenesis of the mandibular body at different rates on the integrity of the condylar cartilage in rabbits. Material and Methods: This study was performed on 2 groups of twelve healthy rabbits (adult male) : (group 1 and group 2) each group (n=6 rabbits, and 12 joints). Two rabbits (4 joints) in each subgroup according to the post distraction period (1, 2, and 4 weeks). In group 1, the distraction was performed daily at rate of 1 mm for 5 days. In group 2, the distraction was performed twice daily at rate of 1.5 mm (3 mm per day) for 5 days.Results: Animals in both groups (1 and 2) showed changes in condylar head, which seemed to be reversible according to the post distraction period. After the first week, condylar layers were decreased in thickness with irregular fibrous outline, bone trabeculae were decreased in number and invaded by large number of osteoclasts. After the second week, the condylar head showed evidence of regeneration of all layers including the disc. After the fourth week, the subchondral area started to be refilled with new bone with numerous osteoblast. Group 2 (3 mm per day) showed more bone and collagen formation.Conclusion: this experimental study reported that distraction rates of 1 mm per day and 3 mm per day showed degenerative change in the TMJ condylar cartilage in the first post distraction week. At the second week, all the condyles showed adaptive and remodeling signs. Regeneration to the normal histological structure appeared in the fourth post distraction weeks, in group 2 (3 mm per day) more than in group 1 (1 mm per day).

Peripheral Blood Stem Cell Therapy Does Not Improve Outcomes of Femoral Head Osteonecrosis With Cap‐Shaped Separated Cartilage Defect

A combination treatment with porous tantalum rod implantation and intra-arterial infusion of peripheral blood stem cells (PBSCs) provides a promise for treating early and intermediate stages of osteonecrosis of the femoral head (ONFH). However, its clinical indications and application restrictions remain unclear. This study aims to determine the clinical, histological, and radiological outcomes of a combination treatment using mechanical support and a targeted intra-arterial infusion of PBSCs for painful ONFH with a cap-shaped separation (CSS) cartilage defect. Compared with the standard pain management (control group), this combination treatment did not improve the Harris Hip Score (HHS) at 36 months. Micro-CT and histologic analyses showed severe focal destruction in all CSS-ONFH femoral heads in both the combination and control groups. Femoral heads showed a higher percentage of bone lesions in the combination treatment group than in the control group. There was no significant difference in osteoclast number in the subchondral bone areas between the two groups. A high level of expression of inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β, was detected in blood vessels around the subchondral bone in both groups. The RANKL/OPG (receptor activator of the nuclear factor-kB ligand/osteoprotegerin) ratio was also similar between the control and combination treatment groups. Our results indicate that this combination treatment is not an effective method for the treatment of patients with painful CSS-ONFH. Moreover, this combination treatment did not inhibit inflammatory osteoclastogenesis in patients with more advanced disease. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:269-276, 2020.

Diagnostic issue on spontaneous osteonecrosis of medial tibial plateau.

To the Editor: I read with great interest the recent report of Yang et al[1], “Clinical Characteristics and Treatment of Spontaneous Osteonecrosis of Medial Tibial Plateau: A retrospective case study” (published on November 5, 2018, Chin Med J, page 2544–2550), because there have been very few reports on isolated spontaneous medial tibial plateau osteonecrosis and little is known about osteonecrosis of the tibial plateau. I would like to comment on diagnostic issues in this letter. Osteonecrosis of the knee can be a devastating disease that leads to end-stage arthritis of the knee. The knee is the second most commonly affected site after the hip.[2] Spontaneous osteonecrosis of the knee (SPONK) involving medial femoral condyle was described as a distinct entity by Ahlback et al in 1968[3] and is also called idiopathic or primary osteonecrosis to distinguish it from secondary osteonecrosis, which is associated with corticosteroid therapy, blood dyscrasias, Gaucher disease, caisson disease,[4] and other rare conditions, for example, laser-assisted arthroscopic chondroplasty.[5] The condition usually involves a single condyle, most often the medial femoral condyle, affected in 94% of the cases and can also occur in the lateral femoral condyle or in the tibial plateaus.[6] Involvement of the tibial plateau, which was first reported in the French literature by d’Angelijan et al[7] in 1967 and was described in the English literature by Houpt et al[8] is less common. Only 2% of osteonecrosis around the knee may affect the tibial plateau. The medial tibial plateau is more frequently affected than the lateral.[9] Therefore, to our knowledge, it remains a rare cause of knee pain. In the article, the case group contains 22 patients in 15 months (from March 2015 to June 2016), it means real prevalence may be underestimated. Magnetic resonance imaging (MRI) is both sensitive and specific for recognizing SPONK of both medial femoral condyle and tibial plateau and recommended for detection of the disease, due to its high sensitivity in detecting bone marrow edema.[10] MRI characteristics include a diffuse area of hyperintensity widespread into the metaphysics on T2-weighted images, the focal subchondral area of low signal intensity adjacent to the subchondral bone plate on T1-weighted images and focal epiphyseal contour depressions. But the MRI-detected subchondral bone marrow lesion, comprised of fibrosis, necrosis, edema, and bleeding into fatty marrow in different proportions as well as abnormal trabeculae, is also a common finding in patients with OA.[11] In the article, the MRI images showed in Figures 2 and 5 have no typical MRI signs of spontaneous medial tibial plateau osteonecrosis, MRI T1 and T2 images show cartilage degeneration, narrow of joint space, focal bone marrow edema and formation of subchondral cysts in medial knee compartment. We think it is more likely anteromedial osteoarthritis of knee, not a typical SPONK of medial tibial plateau. Although medial unicompartmental knee arthroplasty is also appropriate surgical indication. We also noted that in the series, there are 17 patients (77%) with a Level III medial meniscus posterior root tears (MMPRT) and the lesions of 68% patients involved the central tibial plateau. Subchondral marrow edema deep to the MMPRT was described as a harbinger of meniscal root failure. Ipsilateral tibiofemoral compartment bone marrow edema and insufficiency fractures are commonly noted in the presence of posterior meniscal tears.[12] Therefore, differential diagnosis is important and the condition has not been clearly discussed. Funding This work was supported by a grant from Ministry of Science and Technology of China (No. 2017YFC0108003). Conflicts of interest None.

A three-dimensional printed porous implant combined with bone grafting following curettage of a subchondral giant cell tumour of the proximal tibia: a case report

BackgroundSubchondral bone is commonly affected in cases of giant cell tumour (GCT) of the proximal tibia. Numerous studies have stated that retaining a sufficient subchondral bone layer could decrease the possibilities of postoperative degenerative changes and mechanical failure of the knee joint. However, the most commonly used methods of cement packing only or cement packing combined bone grafting have some limitations regarding the protection of subchondral bone after surgery. Our paper describes our attempt to reconstruct a tumorous defect associated with the subchondral area in the proximal tibia with a three-dimensional (3D)-printed porous implant combined with bone grafting and our evaluation of the short-term outcomes.Case presentationA 42-year-old man with a Campanacci grade II GCT visited our institution for initial assessment. Radiographs showed a tumour located at the epiphyseal part of the proximal tibia, and had invaded the subchondral area. Considering that the residual subchondral bone had to be protected, we used an autograft to ensure a high integration rate between the graft and host subchondral bone. We also used three-dimensional (3D) printing technology to design and fabricate a personalized porous implant to mechanically support the graft and subchondral area and help avoid degenerative changes and mechanical failure. At the last follow-up at 29 months postoperatively, the patient had satisfactory limb function and no further damage was seen to the subchondral area and articular surface.ConclusionsThe 3D-printed porous implant combined bone grafting may be a feasible option in the reconstruction of defects that are close to the subchondral area following extensive intracurettage of GCTs. Moreover, it can result in good postoperative function and low complication rates. However, consistent follow-up is required to clarify its long-term outcomes.

Primary ossifying fibroma of the proximal phalanx in a horse

SummaryA primary ossifying fibroma was found at necropsy in a 5‐year‐old Welsh pony cross mare that was humanely subjected to euthanasia for an intractable severe left hindlimb lameness. Antemortem radiographs of the left hind pastern were characterised by articular, subchondral and cortical areas of lysis. Primary ossifying fibroma is a rare lesion of the distal limb but should be considered when there is extensive lysis extending into the medulla and proximal cortical bone.

B cells inhibit bone formation in rheumatoid arthritis by suppressing osteoblast differentiation

The function of B cells in osteoblast (OB) dysfunction in rheumatoid arthritis (RA) has not been well-studied. Here we show that B cells are enriched in the subchondral and endosteal bone marrow (BM) areas adjacent to osteocalcin+ OBs in two murine RA models: collagen-induced arthritis and the TNF-transgenic mice. Subchondral BM B cells in RA mice express high levels of OB inhibitors, CCL3 and TNF, and inhibit OB differentiation by activating ERK and NF-κB signaling pathways. The inhibitory effect of RA B cells on OB differentiation is blocked by CCL3 and TNF neutralization, and deletion of CCL3 and TNF in RA B cells completely rescues OB function in vivo, while B cell depletion attenuates bone erosion and OB inhibition in RA mice. Lastly, B cells from RA patients express CCL3 and TNF and inhibit OB differentiation, with these effects ameliorated by CCL3 and TNF neutralization. Thus, B cells inhibit bone formation in RA by producing multiple OB inhibitors.

Meniscal pathologies on MRI correlate with increased bone tracer uptake in SPECT/CT.

To assess the relationship of subchondral bone tracer uptake (BTU) on SPECT/CT and meniscal pathologies on MRI in patients with painful knees. Twenty-five patients who had MRI and SPECT/CT within 3 months without knee surgery or grade ≥3 cartilage lesions were prospectively included. Maximum values of each subchondral femorotibial area were quantified and a ratio was calculated in relation to a femoral shaft reference region, which represented the BTU background activity. Meniscal lesions were graded (intact/degeneration/tear) and meniscal extrusion (no/yes) was assessed using MRI by two musculoskeletal radiologists blinded to the SPECT/CT findings. One-tailed Spearman correlations served for statistics (p < 0.05). Knees with meniscal degeneration or tear showed a significantly higher BTU in the medial femorotibial compartment (p = 0.045) when compared to intact menisci. Meniscal degeneration was associated with an increased BTU in the lateral femorotibial compartment; however, this was not statistically significant (p = 0.143). Patients with an extruded meniscus showed significantly higher BTU compared to a non-extruded meniscus (p < 0.020). Medial femorotibial BTU in SPECT/CT was associated with meniscal pathologies. Highest BTU was found in patients with meniscal tears. SPECT/CT appears to be a useful imaging modality to identify patients with overloading or early osteoarthritis. • Meniscal degeneration and tears correlate significantly with increased BTU using SPECT/CT. • Medial meniscus extrusion is associated with an increased BTU in SPECT/CT. • SPECT/CT allows detection of overloading and early osteoarthritis.

Opposite roles of pannexins in post-traumatic versus aging associated osteoarthritis

Purpose: Osteoarthritis (OA) is a highly disabling and common degenerative joint disease. OA results from pathological changes in all joint tissues during aging or following joint injury. The mechanisms driving disease progression remain unclear, thus resulting in a lack of disease modifying treatments. A hallmarking feature of OA is cartilage degeneration, and chondrocyte hypertrophy is an important driver of cartilage breakdown. Pannexin 3 (Panx3) has been identified as a novel mediator of this process, and our recent study has shown that deletion of the Panx3 gene delays surgically induced cartilage degeneration in the DMM model in mice. Panx1, another member in the pannexin family, shares 60% sequence amino acid homology with Panx3 and is found ubiquitously throughout the joint and the body. Hence, in this study, we examine the systemic effects of global Panx3 and Panx1/Panx3 deletion during aging, with a specific focus on joint and skeletal health. Methods: WT and Panx3-/- mice were aged to 18 and 24 months of age. In parallel, WT and Panx1-/-/Panx3-/- mice were also aged to 24 months of age. MicroCT analysis was used to investigate bone mineral density and body composition. Joints were harvested, and histopathological analysis of OA development was conducted. The modified OARSI scoring system was used to assess cartilage destruction during aging. OsteoMeasure software was used to analyze subchondral bone parameters including subchondral thickness and area. Synovial changes were assessed using a synovitis scoring system modified from Krenn et al. Results: Our data show that the global loss of Panx3 and Panx1/Panx3 is not associated with increased mortality or significant changes in body composition with aging. We found that bone mineral density changes associated with aging were reduced in Panx3-/- mice compared to WT, although there were no significant differences in absolute bone mineral density at 24 months. Mice lacking Panx3 and Panx1/Panx3 had shorter appendicular and axial skeletons compared to WT mice. Lastly, we showed that loss of Panx3 dramatically accelerated cartilage degeneration with aging, at both 18 and 24 months. This is in sharp contrast to the protective effect previously observed in young mice following joint surgery. At 24 months of age, mice lacking Panx1/Panx3 also showed increased cartilage degeneration compared to WT mice. Conclusions: These studies highlight a novel, OA subtype-specific role for Panx3 in the maintenance of joint health following traumatic injury and with aging. While our previous data shows loss of Panx3 protects against post-DMM OA progression, these data show that loss of Panx3 accelerates OA progression during aging. In conclusion, this study shows that Panx3 and likely Panx1 are essential for the maintenance of cartilage homeostasis in aging mice and reinforces the idea that molecular mechanisms driving post-trauamtic and primary aging associated OA are distinct.

Effect of Vertical or Beveled Chondral Defect Creation on Rim Deformation and Contact.

To determine biomechanical effects of knee cartilage defect perimeter morphology based on cartilage strain and opposing subchondral bone contact. Articular cartilage defects were created in 5 bovine femoral condyles: group 1, 45° inner bevel with 8-mm rim; group 2, vertical with 8-mm rim; and group 3, 45° outer bevel with 8-mm base. Samples were placed into a custom-machined micro-computed tomography tube and subjected to 800 N of axial loading. DICOM data were used to calculate cartilage thickness 4 and 6 mm from the center, distance between tibial cartilage surface and femoral subchondral bone, and contact width between tibial cartilage and subchondral bone. Strain 4 mm from the center and both absolute and change in distance (mm) to subchondral bone were compared between groups 1 and 2 using paired t tests. Strain at 6 mm and distance changed, loaded distance, and contact width (mm) were compared between groups using the Friedman test with post hoc analysis using Wilcoxon signed rank test. No significant differences in rim strain were noted between groups 1 and 2 at 4 mm ( P = 0.10) and between groups 1, 2, and 3 at 6 mm ( P = 0.247) from the defect center. The loaded distance was significantly different between groups 1 and 3 ( P = 0.013). No significant change in distance to the subchondral bone was found between groups ( P = 0.156). The difference in subchondral bone contact area approached but did not reach significance ( P = 0.074). When debriding focal articular cartilage defects, establishment of an inner bevel decreases tissue deformation and contact with opposing subchondral bone.

Assessment of the zonal variation of perfusion parameters in the femoral head: a 3-T dynamic contrast-enhanced MRI pilot study.

The objective was to describe MR perfusion characteristics of the femoral head, with a focus on the subchondral bone. This prospective monocentric study was approved by our local Ethics Committee. Written informed consent was obtained from all subjects. Dynamic contrast-enhanced MRI of the right hip was performed in 59 adults with suspected spondyloarthritis (32 women, 28 men). Mean age was 37.5 (±12.5) years. Regions of interest were drawn in the femoral head epiphysis, in the subchondral areas the most exposed to mechanical load (superolateral, anterosuperior, and posterior zones) and in areas less exposed to mechanical load (inferior subchondral zone and center of the femoral head). Semi-quantitative and pharmacokinetic parameters were calculated using the Tofts model. Statistical analysis was performed with a linear mixed model to compare the perfusion parameters in the different femoral head zones. Extravascular extracellular volume and area under the curve were lower in the superolateral zone than in the inferior zone (p=0.0135 and p<0.0001 respectively) and the central zone (p=0.007 and p=0.0134 respectively). Extravascular extracellular volume and rate constant were lower in the anterosuperior zone than in the inferior zones (p=0.011 and p=0.029). In the anterosuperior zone, extravascular extracellular volume was lower, and time to peak was higher than in the central zones (p=0.0056 and p=0.0013 respectively). No significant differences were found for any values between other paired zones. The perfusion of femoral head subchondral bone assessed with dynamic contrast-enhanced magnetic resonance imaging is not homogeneous: the areas exposed to more mechanical loading are less perfused.

Bone replaces articular cartilage in the rat knee joint after prolonged immobilization

BackgroundLost joint range of motion (ROM) is common in chronic osteoarthritis, alters regional weight-bearing across the articular surfaces, and contributes to loss of cartilage and bone alterations. Limited data exist on the regional effects on joints subjected to chronic losses of ROM. ObjectiveTo characterize the regional replacement by bone as part of articular cartilage degeneration after prolonged immobilization. MethodsEleven rat knees were rigidly-immobilized in flexion for 32weeks with contralateral and sham-operated (n=6) knees as controls. Sagittal medial tibial epiphysis histological sections assessed the anterior (non-weight-bearing), middle and posterior (both weight-bearing) regions. We quantified the distribution of collagen I, collagen II, cartilage thickness, glycosaminoglycan (GAG) staining, Mankin scoring, and subchondral bone plate cross-sectional area. Using immunohistochemistry (IHC), we visualized blood vessels, osteoblasts, and mesenchymal stem cells (MSCs). ResultsImmobilized cartilage had increased collagen I content in the anterior tibial region with picrosirius red staining (immobilized=61±20%; contralateral=43±12%, p=0.033; sham=20±10%, p=0.028) and collagen I IHC (immobilized=40±10%; contralateral=11±4%, p=0.003; sham=5±3%, p=0.043). Articular cartilage was thinner anteriorly (18±30μm) in immobilized knees versus contralateral (124±40μm, p<0.001) and sham (125±43μm, p=0.043). GAG staining covered 2±4% of the anterior articular area in immobilized knees versus 28±12% contralaterally (p=0.003) and 26±7% in sham (p=0.043). Mankin scores in immobilized knees were 4.7±1.7 versus 0.2±0.4 and 0±0 for contralateral and sham (p=0.003, p=0.042), respectively. The trabecular bone plate area of anterior and posterior regions showed relative loss of cross-sectional area in immobilized knees compared to controls (immobilized/contralateral area ratios of 0.67 and 0.46 respectively, both p=0.003), while the area in the middle region was preserved. Movat's pentachrome stain and CD31 staining showed chondral vascular ingrowth from subchondral bone. Osteocalcin and CD90 MSC staining were decreased in immobilized knees versus contralateral (p=0.003, p=0.036 respectively). ConclusionsBony replacement characterizes articular cartilage degeneration of knees immobilized for 32weeks in the anterior, non-weight bearing region of the tibia. Replacement of cartilage by bone may have been mediated by chondral vascularization, suggesting irreversible changes. These findings stress the importance of weight-bearing and joint motion to maintain cartilage structure.

Biomimetic design and fabrication of multilayered osteochondral scaffolds by low-temperature deposition manufacturing and thermal-induced phase-separation techniques

Integrative osteochondral repair is a useful strategy for cartilage-defect repair. To mimic the microenvironment, it is necessary that scaffolds effectively mimic the extracellular matrix of natural cartilage and subchondral bone. In this study, biomimetic osteochondral scaffolds containing an oriented cartilage layer, a compact layer, and a three-dimensional (3D)-printed core-sheath structured-bone layer were developed. The oriented cartilage layer was designed to mimic the structural and material characteristics of native cartilage tissue and was fabricated with cartilage matrix-chitosan materials, using thermal-induced phase-separation technology. The 3D-printed core-sheath structured-bone layer was fabricated with poly(L-lactide-co-glycolide)/β-tricalcium phosphate-collagen materials by low-temperature deposition technology, using a specially designed core-sheath nozzle, and was designed to mimic the mechanical characteristics of subchondral bone and improve scaffold hydrophilicity. The compact layer was designed to mimic the calcified-layer structure of natural cartilage to ensure the presence of different suitable microenvironments for the regeneration of bone and cartilage. A dissolving-bonding process was developed to effectively combine the three parts together, after which the bone and cartilage scaffolds exhibited good mechanical properties and hydrophilicity. Additionally, goat autologous bone mesenchymal stem cells (BMSCs) were isolated and then seeded into the bone and cartilage layers, respectively, and following a 1 week culture in vitro, the BMSC-scaffold constructs were implanted into a goat articular-defect model. Our results indicated that the scaffolds exhibited good biocompatibility, and 24 weeks after implantation, the femoral condyle surface was relatively flat and consisted of a large quantity of hyaloid cartilage. Furthermore, histological staining revealed regenerated trabecular bone formed in the subchondral bone-defect area. These results provided a new method to fabricate biomimetic osteochondral scaffolds and demonstrated their effectiveness for future clinical applications in cartilage-defect repair.

Articular impaction injuries in the lower limb.

The effective management of articular impacted fractures requires the successful elevation of the osteochondral fragment to eliminate joint incongruency and the stable fixation of the fragments providing structural support to the articular surface.The anatomical restoration of the joint can be performed either with elevation through a cortical window, through balloon-guided osteoplasty or direct visualisation of the articular surface.Structural support of the void created in the subchondral area can be achieved through the use of bone graft materials (autologous tricortical bone), or synthetic bone graft substitutes.In the present study, we describe the available techniques and materials that can be used in treating impacted osteochondral fragments with special consideration of their epidemiology and treatment options.Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160072. Originally published online at www.efortopenreviews.org

Longitudinal change in patellofemoral cartilage thickness, cartilage T2 relaxation times, and subchondral bone plate area in adolescent vs mature athletes

ObjectivePatellofemoral cartilage changes have been evaluated in knee trauma and osteoarthritis; however, little is known about changes in patellar and trochlear cartilage thickness, T2 relaxation-time and subchondral bone plate area (tAB) during growth. Our prospective study aimed to explore longitudinal change in patellofemoral cartilage thickness, T2 and tAB in adolescent athletes, and to compare these data with those of mature (i.e., adult) athletes. Materials and methods20 adolescent (age 16±1years) and 20 mature (46±5years) volleyball players were studied over 2-years (10 men and 10 women each group). 1.5T MRI 3D-VIBE and multi-echo spin-echo sequences were acquired at baseline and 2-year follow-up. Using manual segmentation and 3D reconstruction, longitudinal changes in patellar and trochlear cartilage thickness, patellar cartilage T2 (mono-exponential decay curve with five echoes [9.7–67.9ms]), and patellar and trochlear tAB were determined. ResultsThe annual increase in both patellar and trochlear cartilage thickness was 0.8% (95% confidence interval [CI] 0.6, 1.0) and 0.6% (0.3, 0.9), for adolescent males and females respectively; the longitudinal gain in patellar and trochlear tAB was 1.3% (1.1, 1.5) and 0.5% (0.2, 0.8), and 1.6% (1.1, 2.2) and 0.8% (0.3, 0.7) for adolescent males and females, respectively (no significant between-sex differences). Mature athletes showed smaller gains in tAB, and loss of <1% of cartilage thickness annually. While no significant sex-differences existed in adolescent patellar T2 changes, mature males gained significantly greater T2 than mature females (p=0.002–0.013). ConclusionsPatellar and trochlear cartilage thickness and tAB were observed to increase in young athletes in late adolescence, without significant differences between sexes. Mature athletes displayed patellar cartilage loss (and T2 increases in mature males), potentially reflecting degenerative changes.

The Effects of Intra-articular Monosodium Iodoacetate Injection on Joint Pain and both Tibiofemoral and Patellofemoral Joints in Rat Knee

Purpose: Several experimental animal models have been developed for human osteoarthritis (OA) and used to study the preclinical efficacy of disease and symptom modifying OA drug candidates in various species. One of these models is induced chemically by an intra-articular injection of monosodium iodoacetate (MIA) into rat knee. Intra-articular MIA disrupts chondrocyte glycolysis through the inhibition of glyceraldehyde-3-phosphate dehydrogenase, results in chondrocyte death and damage in the entire joint space, and leads to OA symptoms. Hitherto, most data of MIA-induced damage in rat knee has been obtained from tibiofemoral joint and not much information is available from patellofemoral junction. In order to improve this rat MIA model as the animal model of OA in preclinical efficacy studies, the effects of intra-articular MIA injection were characterized on the entire rat knee including both tibiofemoral and patellofemoral joints. Methods: The study was conducted using male Lewis rats. Unilateral OA was induced in their knee joints at the age of 3 months by the intra-articular injection of MIA at the dose of 1 mg. The effects of MIA injection on body weight and OA symptoms were followed during the study. Knee joint discomfort and pain were used as OA symptoms. The knee joint discomfort was determined as static weight bearing and measured as hind paw weight distribution using Incapacitance Tester. The knee joint pain was determined as static mechanical secondary allodynia and measured as paw withdrawal threshold using von Frey monofilaments. Rats were terminated at 4 weeks after the MIA injection and their hind limbs were harvested for analyses. Digital radiographs were obtained and both tibiofemoral and patellofemoral joints were analyzed in radiographs using Carimas software. Knee joints were fixed and representative images were obtained by micro-computed tomography. Then, knee joints were decalcified, embedded in paraffin, and sectioned in a coronal plane. The histological OA assessment of tibiofemoral joint was performed according to the recommendations of Osteoarthritis Research Society International (OARSI) histopathology initiative followed by the analysis of epiphyseal bone structure. Knee joints were also embedded in plastic without decalcification and sectioned in a sagittal plane. Both tibiofemoral and patellofemoral joints were analyzed by bone histomorphometry. For the determination of dynamic histomorphometry parameters, bone labelling was performed with oxytetracycline at 8 days and with calcein green at one day before sacrifice. This experimental protocol was approved by National Animal Experiment Board, Regional State Administrative Agency for Southern Finland, Hämeenlinna, Finland. Results: Intra-articular MIA injection into rat knee decreased paw withdrawal threshold, starting at 3 days after the injection and continuing up to the end of the study. This demonstrated the presence of mechanical hypersensitivity and neuropathic pain in MIA-injected hind limb. In tibiofemoral joint, the neuropathic pain was associated with mild to moderate degenerative changes demonstrated by increased total joint and tibial scores and increased cartilage degeneration width and volume. The cartilage degeneration included the loss of chondrocytes, proteoglycans and collagen matrix down to intermediate layer. These degenerative changes were observed together with a reduction in the amount of epiphyseal bone including decreased epiphyseal bone area fraction, decreased trabecular bone area fraction and decreased subchondral bone plate area. In MIA-injected patellofemoral joint, the neuropathic pain was associated with apparent damage including the degradation of articular surface both in femoral condyle and patella and a reduction in the density of subchondral bone in patella. Dynamic bone histomorphometry revealed impaired and ceased endochondral ossification in the articular cartilage of MIA-injected tibiofemoral and patellofemoral joints, respectively, in association with increased subchondral bone turnover. Conclusions: This study characterized the effects of intra-articular MIA injection on the entire rat knee including both tibiofemoral and patellofemoral joints together with OA symptoms in the rat MIA model used widely in the preclinical efficacy studies of OA. The injection of MIA induced a neuropathic pain in association with a significant damage both in tibiofemoral and patellofemoral joints. Therefore, treatment effects on the patellofemoral joint could be studied as well when testing the preclinical efficacy of OA drug candidates in the rat MIA model.

Radiological morphology variances of transient osteoporosis of the hip.

Although several morphological abnormalities or variances of the hip joint have been proposed to be associated with hip joint degeneration, few studies have investigated any radiological features in patients with transient osteoporosis of the hip (TOH). The purpose of this study is to evaluate the morphological variances of the hip joint in TOH patients radiographically. The TOH group consisted of 31 hips in 31 patients. Age- and gender-matched asymptomatic hips in patients with unilateral osteonecrosis of the femoral head were served as controls. Radiographs and MRI were utilized to examine the following parameters: acetabular dysplasia, acetabular overcoverage, acetabular retroversion, and asphericity of the femoral head-neck junction. Also, localization of the main bone marrow edema (BME) lesion was investigated. TOH patients had a significantly higher incidence of acetabular retroversion (52% with a positive cross-over sign and 29% with posterior wall deficiency) than the controls (13%, P=0.0023; 6%, P=0.043, respectively), which was also confirmed by smaller acetabular anteversion angles on axial MRI. In addition, TOH patients tended to show asphericity of the anterior femoral head-neck junction compared to controls (39% vs. 13%, P=0.040). In 90% of the TOH patients, the main BME lesion was located in the subchondral area of the superior portion of the femoral head, and 77% of the lesion were recognized as a band-like pattern in MRI. Acetabular retroversion and asphericity of the femoral head-neck junction were more commonly observed in TOH patients compared to controls. The main BME lesion was most frequently located in the superior portion of the femoral head.

Transient osteoporosis of the hip: review of the literature.

Transient osteoporosis of the hip (TOH) is a temporary clinical condition of unknown etiology which usually resolves with conservative therapy though may be complicated by fracture or progression to avascular necrosis (AVN). TOH may be slightly more prevalent in men but when it occurs in women, it is most often seen in the latter part of pregnancy. Though fracture is a rare complication of TOH when it occurs, it is most often associated with TOH occurring in pregnancy. Magnetic resonance imaging (MRI) is the best method to diagnosis TOH. Low signal intensity on T1-weighted images, high signal intensity on T2-weighted images, and homogenous pattern of edema (the femoral head and/or neck) with normal subchondral area are in favor of TOH. A shortened course to recovery is reported by use of bisphosphonates, calcitonin, or teriparatide. Based on reported cases, core decompression is not superior to medical therapy. Transient osteoporosis of the hip, which often has no known etiology, usually resolves with conservative therapy but may predispose the patient to fracture or avascular necrosis. Diagnostic method of choice is magnetic resonance imaging. Bisphosphonates, calcitonin, or teriparatide are reported as a useful approach to reduce duration of recovery.

Transient Bone Marrow Edema Syndrome versus Osteonecrosis: Perfusion Patterns at Dynamic Contrast-enhanced MR Imaging with High Temporal Resolution Can Allow Differentiation.

Purpose To prospectively evaluate the perfusion patterns at quantitative dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging of transient bone marrow edema syndrome (TBMES) and avascular osteonecrosis. Materials and Methods Institutional review board approval and written informed consent were obtained. Thirty-two patients (21 men, 11 women; mean age, 48 years; 26 hips, 10 knees) underwent conventional MR imaging and a dynamic contrast-enhanced three-dimensional spoiled gradient-echo sequence at 3 T. Parameter maps for mean transit time (MTT) and plasma flow (PF) were evaluated qualitatively and quantitatively. Differences in perfusion patterns were analyzed by using the Fisher exact test. Regions of interest were drawn in areas of high PF and long MTT on each parametric map. Mean, median, standard deviation, minimum, and maximum values were determined. TBMES and osteonecrosis were compared statistically by using the Mann-Whitney U and Wilcoxon signed-rank tests, with a P value of less than .05 considered indicative of a significant difference. Results Nineteen joints with TBMES and 17 joints with osteonecrosis were evaluated. TBMES joints showed a subchondral elongated area of high PF and low MTT that was surrounded by an area of long MTT and low PF. Osteonecrosis joints showed a subchondral area with low or no detectable PF and MTT adjacent to the joint surface, which was surrounded by a rim of high PF and intermediate MTT. Patterns for TBMES and osteonecrosis did not overlap. A significant difference (P < .001) in PF in the immediate subchondral area was found between TBMES and osteonecrosis; in joints with osteonecrosis, this was comparable to background noise, and therefore, could not be quantified. In the circumscribed rim of high PF and intermediate MTT, which was only found in joints with osteonecrosis, mean ± standard deviation PF was 18.9 mL/100 mL per minute ± 11.0 and mean MTT was 213.3 seconds ± 56.8. No significant difference between TBMES and osteonecrosis was found for MTT (P = .09) and PF (P = .75) in the surrounding area. Conclusion Parameter maps derived at dynamic contrast-enhanced MR imaging with high temporal resolution can allow differentiation of osteonecrosis from TBMES in hip and knee joints. © RSNA, 2016 Online supplemental material is available for this article.

Clinical outcomes after arthroscopic acetabular labral repair using knot-tying or knotless suture technique

The purpose of the study was to compare the clinical results of arthroscopic labral repair using knot-tying and knotless suture anchor techniques for patients with labral tears. From September 2012 to May 2013, we performed a randomized, prospective analysis of 40 hips with labral tears treated with arthroscopic labral repair via knot-tying (group A) or knotless suture anchors (group B). A total of 33 patients were treated for labral tears, and 7 of them received bilateral labral repair. Outcomes and intraoperative parameters were prospectively measured with the UCLA score, the modified Harris Hip Score (MHHS), the Hip disability and Osteoarthritis Outcome Score (HOOS), and the Hip Outcome Score (HOS). Three patients (3 hips) were lost to follow up. A total of 37 hips (30 patients) were finally analyzed: 19 hips in group A and 18 in group B. The mean traction time for group A and group B was 72.2 versus 68.7min, respectively (p=0.314). Although the clinical outcome scores in both groups improved between the initial and final visits, there was no difference in measurements parameters between the two groups. Survival rate, using reoperation or progression of osteoarthritis as the primary end points, was 100%. 83% of cases had excellent and good MHHS scores after 2years of follow-up. During arthroscopic surgery, the drill penetrated the closing subchondral area or the joint in three hips. There was no progression of arthritic change at the latest follow-up. Labral repair with either knot-tying or knotless suture anchor resulted in significant postoperative improvements and no difference between the two groups after 2years of follow-up.