Treatment of a Neglected Patellar Tendon Rupture with a Modified Surgical Technique: Ipsilateral Semitendinosus Autograft Reconstruction with Suture Tape Augmentation.

Patellar tendon ruptures are rare, but debilitating injuries are typically seen in young active males in the third and fourth decades of life. They can occur as a single acute injury or from repetitive microtrauma weakening the tendon. Patients typically present complaining of knee pain, swelling, and an inability to perform a straight leg raise. Most conventionally, these injuries are classified as acute (less than two weeks) or chronic (greater than two weeks) based upon the timing of presentation. In patients with patellar tendon ruptures and inability to perform a straight leg raise, patellar tendon repair is most often recommended. A subset of patients with chronic patellar tendon ruptures, however, presents several months after their initial injuries. These neglected patella tendon ruptures present a particularly challenging clinical scenario in which primary repair is often difficult or not possible. This case report describes a modification to an existing surgical technique for reconstructing the patellar tendon using an ipsilateral semitendinosus tendon autograft with suture tape augmentation.

Digital Radiography in Total Hip Arthroplasty: Technique and Radiographic Results.

BACKGROUND: Obtaining the ideal acetabular cup position in total hip arthroplasty remains a challenge. Advancements in digital radiography and image analysis software allow the assessment of the cup position during the surgical procedure. This study describes a validated technique for evaluating cup position during total hip arthroplasty using digital radiography. METHODS: Three hundred and sixty-nine consecutive patients undergoing total hip arthroplasty were prospectively enrolled. Preoperative supine anteroposterior pelvic radiographs were made. Intraoperative anteroposterior pelvic radiographs were made with the patient in the lateral decubitus position. Radiographic beam angle adjustments and operative table adjustments were made to approximate rotation and tilt of the preoperative radiograph. The target for cup position was 30° to 50° abduction and 15° to 35° anteversion. Intraoperative radiographic measurements were calculated and final cup position was determined after strict impingement and range-of-motion testing. Postoperative anteroposterior pelvic radiographs were made. Two independent observers remeasured all abduction and anteversion angles. RESULTS: Of the cups, 97.8% were placed within 30° to 50° of abduction, with a mean angle (and standard deviation) of 39.5° ± 4.6°. The 2.2% of cups placed outside the target zone were placed so purposefully on the basis of intraoperative range-of-motion testing and patient factors, and 97.6% of cups were placed between 15° and 35° of anteversion, with a mean angle of 26.6° ± 4.7°. Twenty-eight percent of cups were repositioned on the basis of intraoperative measurements. Subluxation during range-of-motion testing occurred in 3% of hips despite acceptable measurements, necessitating cup repositioning. There was 1 early anterior dislocation. CONCLUSIONS: Placing the acetabular component within a target range is a critical component to minimizing dislocation and polyethylene wear in total hip arthroplasty. Using digital radiography, we positioned the acetabular component in our desired target zone in 97.8% of cases and outside the target zone, purposefully, in 2.2% of cases. When used in conjunction with strict impingement testing, digital radiography allows for predictable cup placement in total hip arthroplasty.

Current trends in rotator cuff repair: surgical technique, setting, and cost.

PURPOSE: The purpose of this study was to evaluate national trends in the surgical setting and hospital costs of shoulder arthroscopy and rotator cuff repair (RCR) using the Florida State surgical database and national inpatient database. METHODS: In part I we analyzed population-adjusted shifts in RCR technique (arthroscopic v open) in the Florida surgical database from 2000-2007 and quantified the procedural codes associated with arthroscopic and open RCR. In part II we analyzed the Nationwide Inpatient Sample database from 2001-2009 for the total number of inpatient RCRs, the inpatient hospital type (rural, urban non-teaching, or urban teaching), and the cost. RESULTS: Part I showed a 163% increase in outpatient procedures in Florida, with a 353% increase in arthroscopic RCRs. There was a concurrent decrease in open RCRs; however, the overall trend was a 2-fold increase in total RCRs. Associated procedures such as subacromial decompression, distal clavicle resection, and extensive glenohumeral debridement increased by 440%, 589%, and 1,253%, respectively. Part II showed an overall 58.8% decrease in inpatient RCRs that was similar across all hospital settings, with an increase in RCR-associated hospital charges by 144.9%, whereas hospital costs only increased by 85.2%. CONCLUSIONS: The study confirms a shift toward arthroscopic RCR and associated procedures in the outpatient setting. The increased financial cost partly explains the shift; nevertheless, future studies are needed to further examine national trends. CLINICAL RELEVANCE: This study examining RCR trends by hospital type, cost, and setting further elucidates how orthopaedic surgery practice is evolving with the implementation of arthroscopic RCR in the past decade.

MRI quantification of fatty infiltration and muscle atrophy in a mouse model of rotator cuff tears.

Rotator cuff pathology is the most common shoulder problem seen by orthopedic surgeons. Rotator cuff muscle fatty infiltration and muscle atrophy are common in larger tears and are considered predicting factors for the prognosis of cuff repair. Clinically, MRI is the gold standard in determining fatty infiltration and muscle atrophy; however, analysis for MRI imaging is primarily qualitative in nature with the results lacking further validation. We have recently developed a mouse model of rotator cuff tears. The goal of this study is to quantify and verify rotator cuff muscle atrophy and fatty infiltration using high-resolution MRI in our mouse model. The rotator cuff muscles were analyzed for fat using a triglyceride quantification assay (TQA), muscle volume was measured through water displacement (WD), and histology. The study revealed that MRI had a high correlation with fat as measured with histology and TQA (R(2) =098). MRI also correlated well with atrophy measured with WD and wet weight. This suggests that MRI is a reliable modality in evaluating the progression of fatty infiltration and muscle atrophy following rotator cuff tears in a small animal model.

mTOR regulates fatty infiltration through SREBP-1 and PPARγ after a combined massive rotator cuff tear and suprascapular nerve injury in rats.

Rotator cuff tears (RCTs) are among the most common injuries seen in orthopedic patients. Chronic tears can result in the development of muscular atrophy and fatty infiltration. Despite the prevalence of RCTs, little is known about the underlying molecular pathways that produce these changes. Recently, we have shown that mammalian target of rapamycin (mTOR) signaling plays an important role in muscle atrophy that results from massive RCTs in a rat model. The purpose of this study was therefore to extend our understanding of mTOR signaling and evaluate its role in fatty infiltration after a combined tendon transection and suprascapular nerve denervation surgery. Akt/mTOR signaling was significantly increased and resulted in the up-regulation of two transcription factors: SREBP-1 and PPARγ. We also saw an increase in expression of adipogenic markers: C/EBP-α and FASN. Upon treatment with rapamycin, an inhibitor of mTOR, we observed a decrease in mTOR signaling, activity of transcription factors, and reduction in fatty infiltration. Therefore, our study suggests that mTOR signaling mediates rotator cuff fatty infiltration via SREBP-1 and PPARγ. Clinically, our finding may alter current treatment methods to address rotator cuff fatty infiltration.

Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model.

Atrophy of the rotator cuff muscles is a factor that complicates the treatment of a massive rotator cuff tear (RCT). However, the molecular mechanisms that govern the development of muscle atrophy after RCTs have not been well defined. The Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a central role in maintaining muscle mass in response to mechanical loading. The role of this pathway in the development of muscle atrophy after a massive RCT remains unknown. The purpose of this study was to investigate the regulation of the Akt/mTOR pathway in the development of muscle atrophy after a RCT and suprascapular nerve (SSN) injury. We evaluated the activity of the Akt/mTOR signaling pathway and how this pathway interacts with two atrophy-related genes, MuRF-1 and MAFbx, in supraspinatus muscles of rats that underwent unilateral complete rotator cuff tendon transection or SSN transection. Akt/mTOR activity was significantly reduced after tendon rupture, but increased after nerve injury. MuRF-1 and MAFbx were only up-regulated following denervation. These results suggest that tendon transection leads to a decrease in protein synthesis with down-regulation of the Akt/mTOR signaling pathway, whereas denervation leads to an increase in protein degradation via up-regulation of expression of MuRF-1 and MAFbx.

Muscle degeneration in rotator cuff tears.

Rotator cuff tears are among the most common injuries seen by orthopedic surgeons. Although small- and medium-sized tears do well after arthroscopic and open repair, large and massive tears have been shown to develop marked muscle atrophy and fatty infiltration within the rotator cuff muscles. These pathologic changes have been found to be independent predictors of failed surgical repair with poor functional outcomes. To understand the pathophysiology of rotator cuff disease, we must first develop an understanding of the changes that occur within the cuff muscles themselves. The purpose of this review is to summarize the molecular pathways behind muscular degeneration and emphasize new findings related to the clinical relevance of muscle atrophy and fatty infiltration seen with rotator cuff tears. Understanding these molecular pathways will help guide further research and treatment options that can aim to alter expression of these pathways and improve outcomes after surgical repair of massive rotator cuff tears.

New method for determining apparent axial center of rotation of lumbar and thoracic spine segments.

One main question in spinal kinematics is the determination of the spine's apparent axial center of rotation. Previous research on this topic has yielded contradictory results. The objective of this study was to determine the apparent axial center of rotation for seven lumbar and six thoracic spinal segments by developing and validating a new method. A custom six-degree-of-freedom device, allowing full range of motion, was used with motion recording and analysis software. This system tracked a grid of markers on a specimen when rotational torque was applied in both clockwise and counterclock wise directions at 3.53 Nm, 7.05 Nm, 10.58 Nm, and 14.10 Nm. The area encompassing the apparent axial center of rotation was determined by identifying the five markers with the least amount of motion. The marker angular displacement was calculated as the angle between a virtual line drawn between two points in the initial and final torque conditions. Rotation in both directions was averaged. The lumbar and thoracic spinal segments averaged an apparent axial center of rotation at the posterior border of the vertebral endplates and the anterior border of the spinal canal, with average clockwise to counterclockwise angular displacement ratios of 0.87 and 0.97, respectively.

Diurnal rhythm of cone opsin expression in the teleost fish Haplochromis burtoni.

The biochemical and morphological specializations of rod and cone photoreceptors reflect their roles in sight. The apoprotein opsin, which converts photons into chemical signals, functions at one end of these highly polarized cells, in the outer segment. Previous work has shown that the mRNA of rod opsin, the opsin specific to rods, is renewed in the outer segment with a diurnal rhythm in the retina of the teleost fish Haplochromis burtoni. Here we show that in the same species, all three cone opsin mRNAs (blue, green, and red) also have a diurnal rhythm of expression. Quantitative real-time polymerase chain reaction (PCR) with primer pairs specific for the cone photoreceptor opsin subtypes was used to detect opsin mRNA abundance in animals sacrificed at 3-h intervals around the clock. All three cone opsins were expressed with diurnal rhythms similar to each other but out of phase with the rod opsin rhythm. Specifically, cone opsin expression occurs at a higher level near the onset of the dark period, when cones are not used for vision. Finally, we found that the rhythm of cone opsin expression in fish appears to be light dependent, as prolonged darkness changes normal diurnal expression patterns.