Excision of Intra-articular Knee Heterotopic Ossification Using a 70° Arthroscope.

Heterotopic ossification is ectopic lamellar bone formation within soft tissue and can result in significant functional limitations. There are multiple underlying etiologies of HO including musculoskeletal trauma and traumatic brain injury. Intra-articular HO of the knee is rare and is typically located within the cruciate ligaments. We report a case of a 24-year-old female who presented with worsening right knee pain and limited knee extension two and a half years after a motor vehicle crash with multiple lower extremity fractures. Physical examination of the knee revealed anterior pain, limited extension, and a palpable infrapatellar prominence. Imaging showed a retropatellar tendon, intra-articular excrescence of bone proximal to the anterior tibial plateau. Diagnostic arthroscopy with a 70° arthroscope identified HO at the proximal anterior tibial plateau, which was excised with a high-speed burr under direct visualization. At the three-month follow-up, the patient remained asymptomatic and returned to sport. Retropatellar tendon, intra-articular anterior knee HO is a rare but debilitating clinical entity that can be successfully and safely managed with excision under direct visualization using a 70° arthroscope.

A Patella-Sided Tensioning Technique for Medial Patellofemoral Ligament Reconstruction.

Reconstruction of the medial patellofemoral ligament (MPFL) is a common procedure for treatment of recurrent patellofemoral instability. Over the last two decades, multiple surgical techniques for MPFL reconstruction have been described with no clear consensus on a superior reconstruction technique. Appropriate graft tensioning is one of the most important factors for a successful MPFL reconstruction. Overtensioning of the MPFL graft can lead to patellofemoral joint overload and undertensioning can lead to recurrent instability. Current literature demonstrates descriptions of MPFL reconstruction with final graft tensioning performed off of the femoral side. We describe a technique in this article for performing final graft tensioning from the patellar side, which gives the surgeon an option for intraoperative tension adjustments after evaluating patellar tracking.

Computational Metrics Can Provide Quantitative Values to Characterize Arthroscopic Field of View.

Purpose: The purpose of this study was to determine the inter-rater reliability of arthroscopic video quality, determine correlation between surgeon rating and computational image metrics, and facilitate a quantitative methodology for assessing video quality. Methods: Five orthopaedic surgeons reviewed 60 clips from deidentified arthroscopic shoulder videos and rated each on a four-point Likert scale from poor to excellent view. The videos were randomized, and the process was completed a total of three times. Each user rating was averaged to provide a user rating per clip. Each video frame was processed to calculate brightness, local contrast, redness (used to represent bleeding), and image entropy. Each metric was then averaged over each frame per video clip, providing four image quality metrics per clip. Results: Inter-rater reliability for grading video quality had an intraclass correlation of .974. Improved image quality rating was positively correlated with increased entropy (.8142; P < .001), contrast (.8013; P < .001), and brightness (.6120; P < .001), and negatively correlated with redness (-.8626; P < .001). A multiple linear regression model was calculated with the image metrics used as predictors for the image quality ranking, with an R-squared value of .775 and root mean square error of .42. Conclusions: Our study demonstrates strong inter-rater reliability between surgeons when describing image quality and strong correlations between image quality and the computed image metrics. A model based on these metrics enables automatic quantification of image quality. Clinical Relevance: Video quality during arthroscopic cases can impact the ease and duration of the case which could contribute to swelling and complication risk. This pilot study provides a quantitative method to assess video quality. Future works can objectively determine factors that affect visualization during arthroscopy and identify options for improvement.

A Biomechanical Comparison of Alternative Graft Preparations for All-Inside Anterior Cruciate Ligament Reconstruction.

PURPOSE: To biomechanically compare alternative graft constructs for all-inside anterior cruciate ligament (ACL) reconstruction in the event that the semitendinosus harvested is too narrow or too short to make a graft larger than 8 mm. METHODS: Bovine extensor tendons were used to make 6 different 9-mm-diameter grafts: traditional 4-strand, anastomosis 4-strand, 6-strand, 3-strand, button-fixation 4-strand, and loop-and-tack 4-strand grafts. The grafts were then subjected to cyclic biomechanical testing followed by failure loading. Force at 3 and 5 mm of displacement and ultimate force were recorded for all grafts. RESULTS: Compared with the traditional 4-strand graft, the only graft that showed significant biomechanical differences during the cyclic phase of testing was the button-fixation 4-strand graft, which was characterized by lower force at 3 mm of displacement (74 ± 34 N vs 122 ± 13 N, P = .004) and 5 mm of displacement (122 ± 35 N vs 172 ± 3 N, P = .006). During failure loading, ultimate force was significantly lower for both the 6-strand graft (491 ± 186 N, P = .041) and button-fixation 4-strand graft (326 ± 27 N, P < .001) than for the traditional 4-strand graft (778 ± 176 N). All other grafts were equivalent for the parameters tested. CONCLUSIONS: The anastomosis 4-strand, 3-strand, and loop-and-tack 4-strand grafts do not biomechanically differ in cyclic loading and ultimate force from traditional 4-strand grafts. This study supports the use of anastomosis 4-strand, 3-strand, or loop-and-tack 4-strand grafts in the event that a traditional all-inside 4-strand graft cannot be prepared from a harvested semitendinosus tendon in ACL reconstruction. CLINICAL RELEVANCE: This study tests and describes alternatives to the traditional 4-strand semitendinosus autograft for all-inside ACL reconstruction in the event that the harvested tendon is not adequate.

A Rare Incidence of Pigmented Villonodular Synovitis of the Ankle in an Adolescent.

Pigmented villonodular synovitis mostly affects the knee and other large joints such as the hip. Although the disease is most commonly found in adult patients aged 30 to 40 years, rare cases in children and the elderly have been reported. We present the case of an 11-year-old female who was found to have biopsy-proven pigmented villonodular synovitis in her subtalar joint in 2012. Five years after surgical excision, the patient has continued to be involved in competitive dancing and cheerleading without any pain in her ankle. Moreover, follow-up magnetic resonance imaging studies showed no evidence of recurrence. Our case report emphasizes that the disease should not be solely considered in the middle-age population but should be included in the differential diagnosis of the pediatric patient.

Enhanced uterine artery stiffness in aged pregnant relaxin mutant mice is reversed with exogenous relaxin treatment.

Pregnancy is associated with a progressive remodeling of the uterine artery. This adaptation is influenced by local and systemic pregnancy-dependent factors. We recently demonstrated that the peptide hormone relaxin mediates uterine artery remodeling in late pregnant rats. The objective of this study in relaxin gene knockout (Rln(-/-)) mice was to test the hypothesis that relaxin deficiency throughout pregnancy disrupts uterine artery remodeling, an effect that is exacerbated by aging and reversed with relaxin treatment. Passive mechanical wall properties and extracellular matrix components were measured using pressure myography, quantitative PCR, and zymography in uterine arteries from pregnant wild-type (Rln(+/+)) and Rln(-/-) mice aged 5 and 8 mo on Days 12.5 and 17.5 pregnancy. In a second study, 8-mo-old Rln(-/-) mice received either placebo or human recombinant relaxin subcutaneously for 5 days from Day 12.5 pregnancy. Relaxin deficiency in pregnancy did not alter uterine artery remodeling in young mice. However, remodeling was impaired in older pregnant Rln(-/-) mice, resulting in significantly stiffer uterine arteries. Uterine arteries of aged Rln(-/-) pregnant mice had increased expression of elastin, whereas several matrix metalloproteinases and cell adhesion molecules were decreased relative to Rln(+/+) mice. Fetal weight was also significantly reduced in Rln(-/-) mice in late pregnancy in both young and old dams, whereas placental weight was unchanged. Arterial stiffness and reduced fetal weight were reversed after relaxin treatment. In conclusion, relaxin deficiency compromises uterine artery remodeling in older pregnant females, increasing the risk of pregnancy complications such as hypertension and intrauterine growth restriction.

Podocyte detachment and reduced glomerular capillary endothelial fenestration promote kidney disease in type 2 diabetic nephropathy.

Podocyte detachment and reduced endothelial cell fenestration and relationships between these features and the classic structural changes of diabetic nephropathy have not been described in patients with type 2 diabetes. Here we studied these relationships in 37 Pima Indians with type 2 diabetes of whom 11 had normal albuminuria, 16 had microalbuminuria, and 10 had macroalbuminuria. Biopsies from 10 kidney donors (not American Indians) showed almost undetectable (0.03%) podocyte detachment and 43.5% endothelial cell fenestration. In patients with type 2 diabetes, by comparison, the mean percentage of podocyte detachment was significantly higher in macroalbuminuria (1.48%) than in normal albuminuria (0.41%) or microalbuminuria (0.37%). Podocyte detachment correlated significantly with podocyte number per glomerulus and albuminuria. The mean percentage of endothelial cell fenestration was significantly lower in macroalbuminuria (19.3%) than in normal albuminuria (27.4%) or microalbuminuria (27.2%) and correlated significantly with glomerular basement membrane thickness, albuminuria, fractional mesangial area, and the glomerular filtration rate (iothalamate clearance). Podocyte detachment and diminished endothelial cell fenestration were not correlated, but were related to classic lesions of diabetic nephropathy. Thus, our findings confirm the important role these injuries play in the development and progression of kidney disease in type 2 diabetes, just as they do in type 1 diabetes. Whether podocyte detachment creates conduits for proteins to escape the glomerular circulation and reduced endothelial fenestration lowers glomerular hydraulic permeability requires further study.

The usefulness of MRI in atypical pulled/nursemaid's elbow: a case report.

BACKGROUND: A nursemaid's elbow most frequently occurs with transient longitudinal traction of the pronated forearm and extended elbow, which can be reduced by manipulation without sedation. There are circumstances in which the history is atypical and reduction of the elbow is unsuccessful. Imaging may be helpful in these cases. METHODS: A 33-month-old child was injured in a fall from a tire swing and sustained what was thought to be a nursemaid's elbow. Typical reduction maneuvers were unsuccessful. The patient underwent magnetic resonance imaging (MRI) with conscious sedation, which demonstrated the entrapment of the annular ligament in the radicapitellar joint. A presumed successful reduction was performed with confirmed reduction of the annular ligament by immediate MRI. CONCLUSIONS: To our knowledge, this is the first case report on MRI being used to diagnose and confirm treatment of an atypical nursemaid's elbow. LEVEL OF EVIDENCE: IV.

Podocyte detachment in type 2 diabetic nephropathy.

BACKGROUND: Glomerular podocyte number declines and urinary excretion of podocytes increases as kidney disease progresses in persons with type 2 diabetes mellitus (T2DM). METHODS: Using high-power electron microscopy, we quantified podocyte detachment in T2DM. RESULTS: We evaluated 106 glomeruli (range 1-6 per subject) from 40 Pima Indian subjects with T2DM enrolled in a clinical trial. On high-power electron micrographs, 35% of the subjects had no evidence of podocyte detachment. Among the remaining subjects, the median percentage of basement membrane with podocyte detachment was 0.62% (interquartile range = 0.32-1.52%). CONCLUSION: Podocyte detachment from the glomerular basement membrane has been described and measured in type 1 diabetes mellitus using a different method. We now document podocyte detachment microscopically and quantify it morphometrically in humans with T2DM. The findings offer quantitative histologic support to a potential mechanism for the functional impairment, and possibly the sclerosis of glomeruli, in diabetic glomerular injury.