Can the Acetabular Labrum Be Reconstructed With a Meniscal Allograft? An In Vivo Pig Model.

BACKGROUND: No single graft type has been shown to have a benefit in acetabular labral reconstruction. The native labrum and lateral meniscus share many similarities, suggesting that the meniscus may be a promising source of graft material in labral reconstruction. QUESTIONS/PURPOSES: Using a pig model, we sought to evaluate the healing process of fresh-frozen meniscus allograft for acetabular reconstruction by assessing (1) MRI and macroscopic observations of the meniscus allograft; (2) histologic appearance and immunohistologic evaluation of the meniscus allograft, native meniscus, and labrum; (3) microscopic assessment of the native labrum and meniscus via scanning electron microscopy; and (4) biomechanical assessment of tensile properties. METHODS: Twelve skeletally mature male miniature Bama pigs (24 hips) were randomly divided into two groups: labral defect group (control) and lateral meniscus allograft group. The selection of Bama pig specimens was based on the similarity of their acetabular labrum to that of the human acetabular labrum, characterized by the presence of fibrocartilage-like tissue lacking blood vessels. The pigs underwent bilateral hip surgery. Briefly, a 1.5-cm-long section was resected in the anterior dorsal labrum, which was left untreated or reconstructed using an allogeneic lateral meniscus. The pigs were euthanized at 12 and 24 weeks postoperatively, and then evaluated by macroscopic observations and MRI measurement to assess the extent of coverage of the labral defect. We also performed a histologic analysis and immunohistologic evaluation to assess the composition and structure of meniscus allograft, native labrum, and meniscus, as well as scanning electron microscopy assessment of the microstructure of the native labrum and meniscus and biomechanical assessment of tensile properties. RESULTS: Imaging measurement and macroscopic observations revealed that the resected area of the labrum was fully filled in the lateral meniscus allograft group, whereas in the control group, the labral defect remained at 24 weeks. The macroscopic scores of the meniscus allograft group (8.2 ± 0.8) were higher than those of the control groups (4.8 ± 1.0) (mean difference 3.3 [95% CI 1.6 to 5.0]; p < 0.001). Moreover, in the meniscus allograft group, histologic assessment identified fibrocartilage-like cell cluster formation at the interface between the graft and acetabulum; cells and fibers arranged perpendicularly to the acetabulum and tideline structure that were similar to those of native labrum could be observed at 24 weeks. Immunohistochemical results showed that the average optical density value of Type II collagen at the graft-acetabulum interface was increased in the meniscus allograft group at 24 weeks compared with at 12 weeks (0.259 ± 0.031 versus 0.228 ± 0.023, mean difference 0.032 [95% CI 0.003 to 0.061]; p = 0.013). Furthermore, the tensile modulus of the lateral meniscus allograft was near that of the native labrum at 24 weeks (54.7 ± 9.9 MPa versus 63.2 ± 11.3 MPa, mean difference -8.4 MPa [95% CI -38.3 to 21.4]; p = 0.212). CONCLUSION: In a pig model, lateral meniscus allografts fully filled labral defects in labral reconstruction. Regeneration of a fibrocartilage transition zone at the graft-acetabulum interface was observed at 24 weeks. CLINICAL RELEVANCE: The use of an autograft meniscus for labral reconstruction may be a viable option when labral tears are deemed irreparable. Before its clinical implementation, it is imperative to conduct a comparative study involving tendon grafts, which are extensively used in current clinical practice.

Pectoralis major tendon and enthesis: anatomic, magnetic resonance imaging, ultrasonographic, and histologic investigation.

BACKGROUND: This study evaluates the pectoralis major (PM) tendon humeral insertion, using imaging and histologic assessment in cadaveric specimens. Current descriptions of the pectoralis major tendon depict a bilaminar enthesis, and clarification of the anatomy is important for diagnostic and surgical considerations. MATERIALS AND METHODS: Fourteen fresh-frozen whole upper extremity specimens were used in this study. Magnetic resonance (MRI) and ultrasonographic (US) imaging of the PM muscles, tendons, and entheses were performed, followed by anatomic dissection and inspection. Morphology of the lateral tendon and entheses were evaluated, focused on the presence of layers. In 11 specimens, the lateral 3 cm of the PM tendon was carefully dissected from the footprint, whereas in 3 specimens, the tendon and humeral insertion were preserved and removed en bloc. Histology was performed in axial slabs along the medial-lateral length of the tendon and also evaluated for the presence of layers. RESULTS: The superior-inferior and medial-lateral lengths of the PM footprint were 75 ± 9 mm and 7 ± 1 mm respectively. In all specimens, the clavicular and sternal head muscles and tendons were identified, with the clavicular head tendon generally being shorter. The medial-lateral length of the clavicular head tendon measured 19 ± 8 mm superiorly and 9 ± 3 mm inferiorly. The medial-lateral length of the sternal head tendon measured 38 ± 8 superiorly and 41 ± 18 mm inferiorly. All specimens demonstrated a unilaminar, not bilaminar, enthesis with abundant fibrocartilage on histology. Three specimens demonstrated interspersed entheseal fat and loose connective tissue at the enthesis on MRI and histology. CONCLUSION: The PM tendon humeral insertion consists of a unilaminar fibrocartilaginous enthesis. US, MRI, and histology failed to identify true tendon layers at the enthesis. Delaminating injuries reported in the literature may originate from a location other than the enthesis.

High-field (3 Tesla) MRI of the navicular apparatus of sound horses shows good agreement to histopathology.

Magnetic resonance imaging and the correlation to histopathological findings of the equine palmar foot of lame horses have been described previously, using 0.27 and 1.5 T systems. Compared to these, 3 T systems provide superior spatial resolution and imaging contrast. The aim of our prospective anatomic study was to characterize the imaging anatomy of the navicular region on 3 T MRI in comparison to histopathological findings. We hypothesized that 3 T MRI allows a good visualization of the entire navicular apparatus and reliable measurements of navicular cartilage and cortical bone thickness. Twenty front feet of sound horses were examined using a 3 T MRI system. For histopathological examination, sagittal tissue sections of the navicular bones and adjacent ligaments were prepared. Alterations in magnetic resonance signal were graded for each region and compared to corresponding histological slices. Overall, there was good visualization of the anatomical detail and a very good agreement between MRI and histology for compact bone and spongiosa, good agreement for the fibrocartilage and the distal sesamoidean impar ligament, but only moderate agreement for the hyaline cartilage and the collateral sesamoidean ligament. A comparative measurement of cartilage and cortical bone thickness on magnetic resonance images and histological sections was performed. In MRI, the hyaline cartilage of the articular surface appeared significantly thinner and the fibrocartilage of the flexor surface appeared significantly thicker compared to histology. Findings indicated that MRI at a field strength of 3 T allows reliable depiction of anatomic details of the navicular apparatus.

Morphology of Spring Ligament Fibrocartilage Complex Lesions.

BACKGROUND: The spring ligament fibrocartilage complex (SLFC) is an important static foot stabilizer comprising the superomedial ligament (SML) and the inferior ligament, with anatomical variations (third ligament). The aim of this study was to describe the patterns of the lesions found during SLFC surgery, to allow direct comparison between the results with various surgical techniques. METHODS: Fourteen consecutive patients with SLFC lesions were analyzed during surgical treatment. The mean patient age was 37.3 years, and the mean time from injury was 6.9 months. Intraoperative assessments and anatomical descriptions of the lesions were collected. RESULTS: Three types of lesion were found. In 13 of 14 cases, only the superomedial ligament was involved: five superomedial ligament distentions and eight superomedial ligament ruptures. In one case, total SLFC (superomedial and inferior ligaments) rupture was observed. CONCLUSIONS: The first classification of SLFC lesions is presented, which is simple, consistent, and based on anatomical description.

The Diagnostic Value of Ultrasound in Anterosuperior Acetabular Labral Tear.

PURPOSE: To investigate diagnostic value of ultrasound in acetabular labral tears compared with magnetic resonance (MR) imaging, using arthroscopic surgery as the gold standard in a relatively large sample size. METHODS: We retrospectively evaluated patients who attended the sports medicine clinic of our department and underwent arthroscopic surgery for the diagnosis of an anterosuperior acetabular labral tear between June 2014 and April 2018. All the patients received hip joint ultrasound examination and MR imaging evaluation before arthroscopic surgery. The sensitivity, specificity, and accuracy of ultrasound and MR imaging were calculated and compared. RESULTS: A total of 195 patients were enrolled in this study. Of these, 184 had arthroscopically confirmed anterosuperior acetabular labral tear. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy by ultrasound were, respectively, 68.5%, 81.8%, 98 4%, 13.4%, and 69.2%, retrospectively. For MR imaging, the sensitivity, specificity, PPV, negative predictive value, and accuracy were 84.8%, 63.6%, 97.5%, 20.0%, and 83.6%, respectively. CONCLUSIONS: Although ultrasound had a slightly lower sensitivity for detecting anterosuperior acetabular labral tear, it had a higher specificity and PPV than MR imaging. With the advantages of being inexpensive, relatively quick, noninvasive, and having dynamic evaluation, ultrasound could be used as a feasible method to evaluate anterosuperior acetabular labral tear. LEVEL OF EVIDENCE: Level IV, case series.

Early Achilles Enthesis Involvement in a Murine Model of Spondyloarthropathy: Morphological Imaging with Ultrashort Echo-Time Sequences and Ultrasmall Superparamagnetic Iron Oxide (USPIO) Particle Evaluation in Macrophagic Detection.

Purpose: To confirm the interest of 3-dimensional ultrashort echo-time (3D-UTE) sequences to assess morphologic aspects in normal and pathological Achilles entheses in a rat model of spondyloarthropathy (SpA) with histological correlations, in comparison with conventional RARE T2 Fat-Sat sequences, and, furthermore, to evaluate the feasibility of a 3D multiecho UTE sequence performed before and after the intravenous injection of ultrasmall superparamagnetic iron oxide (USPIO) particles to assess macrophagic involvement in the Achilles enthesis in the same rat model of SpA. Materials and Methods: Fourteen rats underwent in vivo MRI of the ankle at 4.7 T, including a 3D RARE T2 Fat-Sat sequence and a 3D ultrashort echo-time (UTE) sequence for morphologic assessment at baseline and day 3 after induction of an SpA model, leading to Achilles enthesopathy in the left paw (right paw serving as a control). A 3D multiecho UTE sequence was also performed at day 3 before and then 24 (4 rats) and 48 (2 rats) hours after intravenous injection of USPIO. Visual analysis and signal intensity measurements of all images were performed at different locations of the Achilles enthesis and preinsertional area. Visual analysis and T2∗ measurements were performed before and after USPIO injection, on the 3D multiecho UTE sequence in the same locations. Normal and pathological values were compared by Wilcoxon signed-rank tests. MR findings were compared against histological data. Results: 3D-UTE sequences enabled morphologic identification of the anterior fibrocartilage and posterior collagenic areas of the Achilles enthesis. Visual analysis and signal intensity measurements distinguished SpA-affected entheses from healthy ones at day 3 (P=0.02). After administration of USPIO, no differences in signals were detected. Similarly, both visual analysis and signal T2∗ measurements in the enthesis were unable to distinguish the SpA-affected tendons from healthy ones (P=0.914). Neither the normal anatomy of the enthesis nor its pathological pattern could be distinguished using the standard RARE sequence. Histology confirmed the absence of USPIO in Achilles entheses, despite marked signs of inflammation. Conclusion: Unlike conventional RARE T2 Fat-Sat sequences, 3D-UTE sequences enable morphologic assessment of normal enthesis anatomy and early detection of abnormalities in pathological conditions. However, 3D multiecho UTE sequences combined with USPIO injections with T2∗ measurements were unable to detect macrophagic involvement in these pathological conditions.

The Extension-Thickness-Damage (ETD) score: a pre-operative hip MR arthrography-based classification to predict type of labrum surgery.

INTRODUCTION: Hip magnetic resonance arthrography (MRA) is the pre-operative imaging modality of choice in patients with labral damage, with several classifications of labral tears having been reported based on MRA findings. Nevertheless, none of the available classification systems allows the surgeon to predict before surgery how a labral tear could be treated. Our purpose was to develop a new MRA-based scoring system of labral tears to predict before surgery the treatment option more suitable for labral tears. MATERIALS AND METHODS: Forty-seven patients (29 males and 18 females; mean age: 35.9 ± 12.4) performed hip MRA for suspicious of femoroacetabular impingement and were afterwards subjected to arthroscopic treatment. Two musculoskeletal radiologists reviewed all pre-operative examinations and provided the Extension-Thickness-Damage score for each patient, based on Extension of tear, Thickness of labrum, and type of Damage. Chondral lesions grading was based on the arthroscopic findings according to Konan classification. For statistical purposes, patients were divided into two groups, depending on the type of treatment: labral repair or debridement. Mann-Whitney U, Chi-square, receiver operator curves, and Cohen kappa statistics were used. RESULTS: 35/47 underwent repair, while 12/47 were debrided. In both groups, the median chondral damage was grade III, with no significant differences (p = 0.439). The median Extension-Thickness-Damage score in the repair group (6) was significantly lower (p < 0.001) than that in the debridement group (8). The highest diagnostic performance (area under the curve) of Extension-Thickness-Damage was 0.819. The inter-observer agreement was substantial in the evaluation of Extension (k = 0.626) and Thickness (k = 0.771), and almost perfect for Damage (k = 0.827). Higher scores of Extension and Thickness were more frequently associated with debridement (p < 0.001; p = 0.0016, respectively), with no significant differences on the basis of Damage parameter (p = 0.284). CONCLUSIONS: The MRA-based Extension-Thickness-Damage score could represent a helpful pre-operative tool, expressing the extent of the damage and its reparability before arthroscopy.

Ultrasound pathology of the entheses in an age and gender stratified sample of healthy adult subjects: a prospective cross-sectional frequency study.

OBJECTIVES: Ultrasound (US) examination of the entheses is increasingly used. However, little is known about US findings in the entheses in asymptomatic persons. The aim of this study was to investigate the appearance of US signs in the enthuses of the lower limb in asymptomatic subjects. METHODS: We recruited 64 subjects, eight women and eight men whose ages covered four decades, from 20 to 60 years. None had tendon or joint disease in the lower limbs. Participants were examined by a rheumatologist and blood samples were collected to rule out enthesis pathology. The enthesis of the dominant leg were examined with grey-scale and Doppler US to evaluate increased thickness, changed structure, enthesophytes/calcifications, erosions, and colour Doppler signal. RESULTS: Ultrasound examination of 320 entheses was made. At enthesis level, elementary lesions were seen at 73 (22.8%) sites, at subject-level 47 (73.4%) persons showed elementary lesions, in 27 (57%) only one enthesis was affected. Doppler activity was seen in four sites, three at the quadriceps insertion. Most common US elementary lesion was enthesophytes at the Achilles and quadriceps tendon insertion. A tendency towards more elementary lesions was seen in men, and a slight increase was seen with increasing age, however, not statistically significance. CONCLUSIONS: Our findings suggest that US can be used to diagnose/examine subjects in adulthood for pathological changes in the entheses; however, caution should be taken regarding enthesophytes of the quadriceps and Achilles tendon.

Three-dimensional ultrashort echo time (3D UTE) MRI of Achilles tendon at 4.7T MRI with comparison to conventional sequences in an experimental murine model of spondyloarthropathy.

BACKGROUND: Due to the very short T2 of its components, the normal anatomy of Achilles enthesis is impossible to define with "conventional" long echo time (TE) T2 sequences. However, this is a common site affected by rheumatologic disease. Early abnormalities related to inflammatory processes are impossible to detect in this location. PURPOSE: To assess the feasibility of a 3D-UTE (ultrashort echo time) sequence to evaluate normal and pathological Achilles entheses, determining both anterior fibrocartilaginous and posterior collagenic portions at 4.7T, in a rat model of spondyloarthropathy (SpA) with histological correlation. To assess whether this sequence detects SpA enthesopathy prior to long TE T2 sequences, enabling disease monitoring. STUDY TYPE: Prospective case-control study. ANIMAL MODEL: Twelve immunocompetent Wistar male rats imaged before (controls); the model was induced in eight rats (16 tendons) imaged at day 6, day 13, and day 21 with regular sacrifice for ex vivo imaging and histological correlation. FIELD STRENGTH: 4.7T Bruker Biospec Systems. 3D balanced steady-state free precession (bSSFP) and 3D-UTE sequences, performed at baseline (day 0, n = 12 animals / 24 tendons), day 6 (n = 8/16), 13 (n = 4/8), and day 21 (n = 2/4). ASSESSMENT: Visual analysis and signal intensity measurements (signal to noise ratio, SNR) of both bSSFP and UTE images were performed by two independent musculoskeletal radiologists at different locations of the Achilles enthesis and preinsertional area. STATISTICAL TESTS: Normal and pathological rat values were compared by Wilcoxon signed-rank tests, as well as interobserver differences. MRI findings were compared against histological data. RESULTS: The 3D-UTE sequence identified the anterior fibrocartilage and posterior collagenic areas of Achilles entheses in all cases. Visual analysis and signal intensity measurements distinguished SpA-affected entheses from healthy ones at days 6 and 13 (P = 0.002 and P = 0.006, respectively). Neither the normal anatomy of the enthesis nor its pathological pattern could be identified on T2 bSSFP sequences. DATA CONCLUSION: Unlike bSSFP T2 sequences, 3D-UTE sequences enable visualization of normal enthesis anatomy and early detection of abnormalities in pathological conditions. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:127-135.

Revisiting the Anterior Glenoid: An Analysis of the Calcified Cartilage Layer, Capsulolabral Complex, and Glenoid Bone Density.

PURPOSE: In this cadaveric study, we aim to define the basic anatomy of the anterior glenoid with attention to the relationships of calcified cartilage, capsulolabral complex, and osseous morphology of the anterior glenoid. METHODS: Seventeen cadaveric glenoid specimens (14 male, 3 female, mean age 53.9 ± 10) were imaged with micro-computed tomography (CT) and embedded in poly-methyl-methacrylate. Specimens were included for final analysis only if the entire glenoid articular cartilage, labrum, capsule, and biceps insertion were pristine and without evidence of injury, degeneration, or damage during the preparation process. Group 1 members (n = 9) were axially sectioned through 3 to 9 o'clock and 4 to 8 o'clock; group 2 members (n = 8) were radially sectioned through 3, 4, 5, and 9 o'clock. A scanning electron microscope (SEM) analysis quantified the percentage of bone within a 5 × 2.5 mm region at the glenoid rim. Micro-CT, SEM, and light microscopy evaluated the capsulolabral complex and calcified fibrocartilage. RESULTS: A 7 ± 2.1 mm region of calcified fibrocartilage at 4 o'clock was identified from the articular face to the medial glenoid neck supporting the overlying capsulolabral footprint and was >3× thicker at the articular attachment (316 ± 153 µm) versus the glenoid neck (92 ± 66 µm). At 3 to 9 o'clock and 4 to 8 o'clock 79.2% ± 5.4% and 75.2% ± 7.8% of the glenoid osseous width was covered with articular cartilage. The labrum accounted for 13.1% ± 3.4% of the glenoid width at 4 o'clock. SEM analysis demonstrated decreased glenoid bone density at 3, 4, and 5 o'clock (P ≤ .015) and no difference (P = .448) at 9 o'clock versus central subchondral bone. CONCLUSIONS: The capsulolabral footprint contributes significantly to the glenoid face, inserts directly adjacent to the articular cartilage, and extends medially along the glenoid neck. A layer of calcified fibrocartilage lies immediately beneath the capsulolabral footprint and is 3× thicker at the articular insertion compared with the glenoid neck. Lastly, there is a bone density gradient at the anterior-inferior rim versus the central subchondral bone. CLINICAL RELEVANCE: Arthroscopic Bankart repair has been reported to have a significant failure rate in many settings. It is felt that reproducing anatomy with the repair could help improve outcomes. Based on this study's findings, an arthroscopic Bankart technique that most closely reproduces native anatomy and potentially optimizes soft-tissue healing could be performed. This includes removal of 1 to 2 mm of articular cartilage from the glenoid face with anchor placement at this location to appropriately reposition the capsulolabral complex.

Surgical Treatment of Synovial Chondromatosis in the Inferior Compartment of the Temporomandibular Joint With Articular Disc Involvement.

The authors report an unusual case of painful synovial chondromatosis originated in the inferior compartment of the temporomandibular joint (TMJ) with articular disc involvement in a 56-year-old woman with complaint of severe pain in the right preauricular region. Magnetic resonance images showed advanced destruction of the right articular disc anteriorly displaced, condylar erosion, and distinct nodules within an extremely expanded inferior joint compartment with large amount of fluid, as well as a large TMJ effusion. A scintigraphy showed elevated bone uptake in the right TMJ, demonstrating intense bone remodeling activity in the region. After a right internal maxillary artery embolization, the patient underwent open surgery. The intraoperative procedures, including articular disc removal, condylar remodeling, and replacement of the articular disc, are described in detail. Synovial chondromatosis of the TMJ is a rare disease, especially when it affects the inferior compartment and the articular disc. Initial diagnosis is challenging and imaging techniques (magnetic resonance imaging and scintigraphy) play an important role in identifying signs, making accurate diagnosis, and offering additional information not available with conventional imaging, such as TMJ inflammation or remodeling. In these patients, open surgery may be considered a definitive treatment, since the postoperative recurrence rate is very low.

Magnetic resonance imaging evaluation of the labrum to predict acetabular development in developmental dysplasia of the hip: A STROBE compliant study.

Recently, more attention has been paid to the role of the acetabular labrum. Therefore, we designed a retrospective cohort study of patients with residual hip dysplasia (RHD) who underwent magnetic resonance imaging (MRI). The objective of this study was to investigate an association between the MRI appearance of the labrum before school age and the natural history of RHD.We retrospectively investigated 45 hips of 40 patients who underwent MRI at about 3 and 4 years of age for RHD and were conservatively followed up with until 6 years of age or older. We evaluated the extent of eversion with a new method that measures the ß angle (MRI ß angle) using landmarks of the Graf method on MRI T2*-weighted images. The outcome measure was the Severin classification at the final follow-up. We compared the radiographic and MRI parameters at approximately 3 and 4 years of age between the good and poor outcome groups. The Student t test or one-way analysis of variance was used to compare the quantitative variables between groups. The Chi-square test was used to perform a ratio comparison.Although there was a significant difference in the center-edge (CE) angle, there was no significant difference in the acetabular index and the ratio of the presence of femoral head necrosis and the break in Shenton line between the good and poor groups. The MRI ß angle was significantly greater in the poor outcome group than in the normal and good outcome groups. The cut-off value of the MRI ß angle to differentiate the good and poor outcome groups was 65°, and its specificity and sensitivity were 92% and 53%, respectively.There was labral eversion on MRI scans in patients with RHD. Acetabular development before adolescence was poorer with greater labral eversion on MRI scans. The specificity for poor acetabular development was high when the MRI ß angle was 65° or more. The MRI ß angle has the potential to predict acetabular development.

Prevalence and clinical significance of hypertrophic labrum in non-dysplastic hips.

BACKGROUND: Hypertrophic labrum in dysplastic hip has been frequently reported and is known as limbus in developmental dysplasia of the hip. However, hypertrophic labrum without hip dysplasia has not been reported to date. The purpose of this study was to define hypertrophic labrum and to investigate the prevalence and clinical significance of an abnormally hypertrophic labrum in non-dysplastic hips. METHODS: Between 2007 and 2014, direct CT arthrography was performed in 464 patients (470 hips) who had chronic groin pain and positive impingement or Faber test. There were 189 male (192 hips) and 275 female (278 hips) patients. The mean age was 46.8 years (range, 16-74 years). The hypertrophic labrum was defined as a labrum wider than two standard deviations away from the mean. Surgical correlation of hypertrophic labrum was obtained in cases with hip arthroscopy by a single surgeon. RESULTS: Seventeen hips (3.6%) were found to have a hypertrophic labrum which had a mean width of 11.2 mm (±1.1) (range, 9.8-14.1 mm). The average width (±SD) of the labrum without hypertrophy was 5.5 mm (±2.4) (range, 2-9.8 mm). Arthroscopic findings of the hypertrophic labrum included fissure and longitudinal tear at the chondrolabral junction and they were associated with chondral abnormality adjacent to the lesion. CONCLUSIONS: Hypertrophic labrum without hip dysplasia is not rare with a high incidence of tears. Care should be taken during arthroscopic access to the hip joint in patients with this morphologic variation as iatrogenic damage can occur more easily. LEVEL OF EVIDENCE: Case Series; Level IV.

Is there a distinct pattern to the acetabular labrum and articular cartilage damage in the non-dysplastic hip with instability?

PURPOSE: The purpose of this study was to determine whether or not there is a distinct pattern of injury to the acetabular labrum and/or cartilage in the hip with instability without bony dysplasia. METHODS: Surgical records and intra-operative images of consecutive patients who underwent primary hip arthroscopy for femoroacetabular impingement (FAI) and/or hip instability by the senior author from April 2007 to December 2014 were retrospectively reviewed. Pathological changes were documented and charted on a novel diagram of the acetabulum, and classified into eight patterns corresponding to the lesion's location and size. In patients who had acetabular chondroplasty treatment, the width of the cartilage lesion was recorded. RESULTS: A total of 953 hips in 886 patients were included, and patients who met our inclusion/exclusion criterion were grouped into an Instability-Only group (45 hips), an Instability-Dysplasia group (12 hips), as well as Pincer-FAI, Cam-FAI, and Combined-FAI groups consisting of 100, 54, and 269 hips, respectively. In the Instability-Only group, 42.2 % of the chondral and labral lesions demonstrated a "Straight-Anterior" pattern, which proportion was statistically significantly different compared with Pincer-FAI (p < 0.000), Cam-FAI (p = 0.0002), and Combined-FAI (p < 0.000) groups. In Instability-Only patients, only 15.6 % of the lesions had an "Anterior to Lateral" pattern, a significantly lower proportion (p < 0.000) compared with the FAI groups. Also 11.1 % of the lesions demonstrated a "Lateral" pattern, which is a significantly greater proportion compared with Pincer-FAI (p < 0.000) and Combined-FAI (p < 0.000) groups. The mean width of the cartilage lesions for the Instability-Only group was 2.9 mm, which was significantly shallower than for the other FAI groups (p < 0.000). CONCLUSION: A significant predilection of "Straight-Anterior" or "Lateral" location of labral and/or cartilage damage was observed in the hip with instability, while there was shallow width of articular cartilage damage in these patients. These results suggest that there is a distinctive labral and cartilage damage pattern for hips with instability without inherent bony dysplasia. LEVEL OF EVIDENCE: Diagnostic study, Level IV.

New perspectives on femoroacetabular impingement syndrome.

Femoroacetabular impingement (FAI) is characterized by an abnormality in the shape of the femoral head-neck or acetabulum that results in impingement between these two structures. Arthroscopic treatment has become the preferred method of management of FAI owing to its minimally invasive approach. Surgical correction involves resection of impinging osseous structures as well as concurrent management of the associated chondral and labral pathology. Research from the past 5 years has shown that repair of the labrum results in a better anatomic correction and improved outcomes compared with labral debridement. Research is underway to improve cartilage assessment by using innovative imaging techniques and biochemical tests to inform predictions of prognosis. Several ongoing randomized controlled trials, including the Femoroacetabular Impingement Trial (FAIT) and the Femoroacetabular Impingement Randomized Controlled Trial (FIRST), will provide critical information regarding the diagnosis, management and prognosis of patients undergoing arthroscopic management of FAI.

[Features of pathological changes of fibro-cartilaginous tissue knee in patients with Baker cyst.]

Objective: Using magnetic resonance imaging (MRI) to evaluate the characteristics of pathological changes of fibro-cartilage of the knee in patients with Baker cyst, to assess the compliance of degrees of damage stages of osteoarthritis on a scale of Kellgren­Lawrence (K­L), and compare the results with the data of other researchers. Material and Methods: This study included patients (38­82 years) with a cyst Baker accidentally detected during ultrasound veins of the lower extremities. The subjects underwent a single knee MRI. MRI was made in three dimensions using 3D gradient-echo protocol. Independent radiologist evaluated the presence and severity of chondral defect osteophytosis, damage to the menisci and ligaments, intraosseous edema and subchondral cysts. The osteoarthritis stage of the knee were identified by X-ray performed in a standing position in the standard two projections, with K­L scale. Results: In this study, the results of a survey of 20 people, whose average age was 57.2 years. According to the radiological scale of K­L two patients were assigned to the stage 0 degree, 5 people to stage 1, 2, 4 each, and 3 ­ to stage 3. Synovitis of various severity was detected in 85% of the studies. Nineteen visualized the patellar cartilage damage, the condyles of the femur and tibia are most commonly affects the joint area. Among the most commonly injured ligament anterior cruciate ligament was determined ­ 9 (45%) patients in the same amount of detected intramedullary edema condyles femur and tibia. Eighteen subjects had at least one anomaly meniscus detectable by MRI, while in 11 (55%) persons were deviations, at least two or more regions of the knee examined. Conclusions: Our results suggest that not all visualized on MRI degenerative damage to intra fibro-cartilaginous tissue correlate positively with the stages of osteoarthritis of the knee, identified by standard radiographs and may not significantly affect the onset and progression of synovial cyst of the popliteal region.

High-purity magnesium interference screws promote fibrocartilaginous entheses regeneration in the anterior cruciate ligament reconstruction rabbit model via accumulation of BMP-2 and VEGF.

Interference screw in the fixation of autologous tendon graft to the bone tunnel is widely accepted for the reconstruction of anterior cruciate ligament (ACL), but the regeneration of fibrocartilaginous entheses could hardly be achieved with the traditional interference screw. In the present work, biodegradable high-purity magnesium (HP Mg) showed good cytocompatibility and promoted the expression of bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF), fibrocartilage markers (Aggrecan, COL2A1 and SOX-9), and glycosaminoglycan (GAG) production in vitro. The HP Mg screw was applied to fix the semitendinosus autograft to the femoral tunnel in a rabbit model of ACL reconstruction with titanium (Ti) screw as the control. The femur-tendon graft-tibia complex was retrieved at 3, 6, 9 and 12 weeks. Gross observation and range of motion (ROM) of the animal model reached normal levels at 12 weeks. No sign of host reaction was found in the X-ray scanning. The HP Mg group was comparable to the Ti group with respect to biomechanical properties of the reconstructed ACL, and the ultimate load to failure and stiffness increased 12 weeks after surgery. In the histological analysis, the HP Mg group formed distinct fibrocartilage transition zones at the tendon-bone interface 12 weeks after surgery, whereas a disorganized fibrocartilage layer was found in the Ti group. In the immunohistochemical analysis, highly positive staining of BMP-2, VEGF and the specific receptor for BMP-2 (BMPR1A) was shown at the tendon-bone interface of the HP Mg group compared with the Ti group. Furthermore, the HP Mg group had significantly higher expression of BMP-2 and VEGF than the Ti group in the early phase of tendon-bone healing, followed by enhanced expression of fibrocartilage markers and GAG production. Therefore we proposed that the stimulation of BMP-2 and VEGF by Mg ions was responsible for the fibrochondrogenesis of Mg materials. HP Mg was promising as a biodegradable interference screw with the potential to promote fibrocartilaginous entheses regeneration in ACL reconstruction.

External rotation and active supination CT arthrography for the postoperative evaluation of type II superior labral anterior to posterior lesions.

PURPOSE: To evaluate the effectiveness of external rotation and active supination CT arthrography in postoperative evaluation by comparing it with neutral CT arthrography and analyzing its agreement with postoperative clinical results after the repair of type II superior labral anterior to posterior (SLAP) lesions. MATERIALS AND METHODS: A total of 25 patients who had undergone CT arthrography in neutral, external rotation and active supination position at least 1 year after the arthroscopic repair of SLAP lesions were enrolled. Two radiologists independently evaluated the status of the repaired SLAP lesions with neutral CT arthrography and then with external rotation and active supination CT arthrography. RESULTS: Five patients had residual symptoms and positive findings upon SLAP-specific examinations. Agreements between the presence of symptoms and radiologic diagnoses based on neutral CT arthrography were insignificant for reader 1 (κ = 0.138, p = n.s.) and significant for reader 2 (κ = 0.328, p = 0.027). However, agreements were highly significant in the analysis following the evaluation of external rotation and active supination CT arthrography for both readers (κ = 0.694, p < 0.001 in reader 1; κ = 0.783, p < 0.001 in reader 2). CONCLUSIONS: The presence of contrast-filled gaps between the labrum and glenoid on neutral CT arthrography after SLAP repair is frequent with satisfactory clinical outcomes. Gaps without additional widening upon external rotation and active supination CT arthrography may suggest postoperatively stable biceps anchors, so this new method could minimize the overdiagnosis of recurrent SLAP lesions. Additional gap widening on external rotation and active supination CT arthrography could be related to a true recurrent SLAP lesion and the symptoms of the patients. LEVEL OF EVIDENCE: Case series, Level IV.

Ultrasound of the joints and entheses in healthy children.

BACKGROUND: Tendon insertion pathologies such as enthesitis and apophysitis in children can result from trauma, overuse syndrome and arthritis. Knowledge of the US appearance of normal joints by age might aid diagnosis of pathologies. OBJECTIVE: We describe the age-related sonographic features of the elbows, knees and feet in healthy children, providing a reference for the normal appearance of tendon insertions, apophyseal cartilage and bursae. MATERIALS AND METHODS: This is a prospective cross-sectional study of 30 healthy children. Children were grouped according to age: group 1 (4-9 years, n = 11), group 2 (10-13 years, n = 9) and group 3 (14-18 years, n = 10). Children completed pain and function questionnaires and underwent a standardized joint examination by a pediatric rheumatologist. The common extensor, common flexor, quadriceps, patellar and Achilles tendons and plantar fascia insertions were evaluated with gray-scale and power Doppler ultrasound. The anterior elbow, suprapatellar and retrocalcaneal bursae were evaluated for fluid. We measured the apophyseal cartilage thickness at the enthesis. Correlation analyses examined associations between age and tendon thickness. We used ANOVA, with location as a repeated measure, to test for gender differences in cartilage thickness. RESULTS: Children had a median age of 12.4 years and 55% were boys. All 360 entheses appeared normal on gray-scale imaging. There was a strong linear relationship between tendon thickness and age. Tendon vascularity was only present in young children (group 1), in 7/22 (32%) quadriceps tendons. Peri-tendinous power Doppler signal was seen at seven sites: two patellar, four quadriceps and one common flexor tendon, and all these children were in group 2. Suprapatellar bursal fluid <3 mm was detected in 9/60 (15%) knees. Of the children in group 1, boys had thicker apophyseal cartilage than girls at the medial epicondyle, patellar poles and os calcis (P < 0.05). CONCLUSION: Tendon vascularity may be a normal finding in young children, and mild peri-tendinous vascularity is not uncommon in children 10-13 years of age. Tendon thickness has a linear relationship with age; however cartilage thickness varies across sites and also differs as a function of gender.

Endochondral fracture healing with external fixation in the Sost knockout mouse results in earlier fibrocartilage callus removal and increased bone volume fraction and strength.

Sclerostin deficiency, via genetic knockout or anti-Sclerostin antibody treatment, has been shown to cause increased bone volume, density and strength of calluses following endochondral bone healing. However, there is limited data on the effect of Sclerostin deficiency on the formative early stage of fibrocartilage (non-bony tissue) formation and removal. In this study we extensively investigate the early fibrocartilage callus. Closed tibial fractures were performed on Sost(-/-) mice and age-matched wild type (C57Bl/6J) controls and assessed at multiple early time points (7, 10 and 14days), as well as at 28days post-fracture after bony union. External fixation was utilized, avoiding internal pinning and minimizing differences in stability stiffness, a variable that has confounded previous research in this area. Normal endochondral ossification progressed in wild type and Sost(-/-) mice with equivalent volumes of fibrocartilage formed at early day 7 and day 10 time points, and bony union in both genotypes by day 28. There were no significant differences in rate of bony union; however there were significant increases in fibrocartilage removal from the Sost(-/-) fracture calluses at day 14 suggesting earlier progression of endochondral healing. Earlier bone formation was seen in Sost(-/-) calluses over wild type with greater bone volume at day 10 (221%, p<0.01). The resultant Sost(-/-) united bony calluses at day 28 had increased bone volume fraction compared to wild type calluses (24%, p<0.05), and the strength of the fractured Sost(-/-) tibiae was greater than that that of wild type fractured tibiae. In summary, bony union was not altered by Sclerostin deficiency in externally-fixed closed tibial fractures, but fibrocartilage removal was enhanced and the resultant united bony calluses had increased bone fraction and increased strength.