Clinical Assessment of the Dynamic Labral Shear Test for Superior Labrum Anterior and Posterior Lesions.

BACKGROUND: Diagnosing superior labrum anterior and posterior (SLAP) lesions through physical examination remains challenging. The dynamic labral shear test (DLST) has been shown to have likelihood ratios (LRs) of 31.6 and 1.1 for diagnosing SLAP lesions. PURPOSE: To determine the clinical utility of the DLST for diagnosing SLAP lesions. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: This prospective, consecutive case series included 774 patients who underwent diagnostic arthroscopy and a preoperative DLST between 2007 and 2013. Patients were divided into 3 groups: 610 control patients with no SLAP lesion but with other abnormalities, 9 patients with isolated SLAP lesion (ISL), and 155 patients with concomitant SLAP lesion (CSL), who had a SLAP lesion and another shoulder abnormality. We determined sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), odds ratio (OR), and diagnostic accuracy (DA) of the DLST with and without other tests. RESULTS: The DLST was positive for 242 of 610 controls (40%), 7 of 9 patients (78%) in the ISL group, and 88 of 155 patients (57%) in the CSL group. In the ISL group, the DLST had a sensitivity of 78%, specificity of 51%, PPV of 2%, NPV of 100%, OR of 3.58, and DA of 51%. In comparison, the ORs were 1.09 for the active compression test, 1.30 for the lift-off test, and 1.53 for the relocation test, which were not significantly different from each other. For diagnosing a SLAP lesion existing in a joint with other associated injury, the DLST had a sensitivity of 57%, specificity of 52%, PPV of 23%, NPV of 83%, OR of 1.4, and DA of 53%. Combining all 4 tests did not improve the OR for detecting ISLs or CSLs. CONCLUSION: The DLST is sensitive but not specific for detecting ISLs. With an OR of 3.58, the DLST is useful for diagnosing ISLs. However, in patients who have CSLs, the DLST is not as useful for diagnosing SLAP lesions.

Intralesional Osteophyte Regrowth Following Autologous Chondrocyte Implantation after Previous Treatment with Marrow Stimulation Technique.

Objective Bone marrow stimulation surgeries are frequent in the treatment of cartilage lesions. Autologous chondrocyte implantation (ACI) may be performed after failed microfracture surgery. Alterations to subchondral bone as intralesional osteophytes are commonly seen after previous microfracture and removed during ACI. There have been no reports on potential recurrence. Our purpose was to evaluate the incidence of intralesional osteophyte development in 2 cohorts: existing intralesional osteophytes and without intralesional osteophytes at the time of ACI. Study Design We identified 87 patients (157 lesions) with intralesional osteophytes among a cohort of 497 ACI patients. Osteophyte regrowth was analyzed on magnetic resonance imaging and categorized as small or large (less or more than 50% of the cartilage thickness). Twenty patients (24 defects) without intralesional osteophytes at the time of ACI acted as control. Results Osteophyte regrowth was observed in 39.5% of lesions (34.4% of small osteophytes and 5.1% of large osteophytes). In subgroup analyses, regrowth was observed in 45.8% of periosteal-covered defects and in 18.9% of collagen membrane-covered defects. Large osteophyte regrowth occurred in less than 5% in either group. Periosteal defects showed a significantly higher incidence for regrowth of small osteophytes. In the control group, intralesional osteophytes developed in 16.7% of the lesions. Conclusions Even though intralesional osteophytes may regrow after removal during ACI, most of them are small. Small osteophyte regrowth occurs almost twice in periosteum-covered ACI. Large osteophytes occur only in 5% of patients. Intralesional osteophyte formation is not significantly different in preexisting intralesional osteophytes and control groups.

Does preoperative American Society of Anesthesiologists score relate to complications after total shoulder arthroplasty?

BACKGROUND: For hip and knee arthroplasties, an American Society of Anesthesiologists (ASA) score greater than 2 is associated with an increased risk of medical and surgical complications. No study, to our knowledge, has evaluated this relationship for total shoulder arthroplasty (TSA) or reverse total shoulder arthroplasty (reverse TSA). QUESTIONS/PURPOSES: We aimed to assess the relationship between the ASA score and (1) surgical complications, (2) medical complications, and (3) hospitalization length after TSA, reverse TSA, and revision arthroplasty. METHODS: We retrospectively analyzed all patients who had undergone TSAs, reverse TSAs, or revision arthroplasties by the senior author (EGM) from November 1999 through July 2011 who had at least 6 months' followup. Of the 485 procedures, 452 (93.2%) met the inclusion criteria. Data were collected on patient demographics, comorbidities, hospitalization length, and short-term (≤ 6 months) medical and surgical complications. Logistic regression analysis modeled the risk of having postoperative complications develop as a function of the ASA score. RESULTS: Patients with an ASA score greater than 2 had a greater risk of having a surgical complication develop (p < 0.001; OR, 2.27; 95% CI, 1.36-3.70) and three times the risk of prosthesis failure (ie, component dislocation, component loosening, and hardware failure) (p < 0.001; OR, 3.23; 95% CI, 1.54-6.67). Higher ASA scores were associated with prolonged length of hospitalization (effect size 0.46, p < 0.001), but not medical complications. CONCLUSIONS: ASA score is associated with surgical, but not medical, complications after TSA and reverse TSA. The ASA score could be used for risk assessment and preoperative counseling. LEVEL OF EVIDENCE: Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Transcriptional regulation of N-acetylglutamate synthase.

The urea cycle converts toxic ammonia to urea within the liver of mammals. At least 6 enzymes are required for ureagenesis, which correlates with dietary protein intake. The transcription of urea cycle genes is, at least in part, regulated by glucocorticoid and glucagon hormone signaling pathways. N-acetylglutamate synthase (NAGS) produces a unique cofactor, N-acetylglutamate (NAG), that is essential for the catalytic function of the first and rate-limiting enzyme of ureagenesis, carbamyl phosphate synthetase 1 (CPS1). However, despite the important role of NAGS in ammonia removal, little is known about the mechanisms of its regulation. We identified two regions of high conservation upstream of the translation start of the NAGS gene. Reporter assays confirmed that these regions represent promoter and enhancer and that the enhancer is tissue specific. Within the promoter, we identified multiple transcription start sites that differed between liver and small intestine. Several transcription factor binding motifs were conserved within the promoter and enhancer regions while a TATA-box motif was absent. DNA-protein pull-down assays and chromatin immunoprecipitation confirmed binding of Sp1 and CREB, but not C/EBP in the promoter and HNF-1 and NF-Y, but not SMAD3 or AP-2 in the enhancer. The functional importance of these motifs was demonstrated by decreased transcription of reporter constructs following mutagenesis of each motif. The presented data strongly suggest that Sp1, CREB, HNF-1, and NF-Y, that are known to be responsive to hormones and diet, regulate NAGS transcription. This provides molecular mechanism of regulation of ureagenesis in response to hormonal and dietary changes.

Does a modified gap-balancing technique result in medial-pivot knee kinematics in cruciate-retaining total knee arthroplasty? A pilot study.

BACKGROUND: Normal knee kinematics is characterized by posterior femorotibial rollback with tibial internal rotation and medial-pivot rotation in flexion. Cruciate-retaining TKAs (CR-TKAs) do not reproduce normal knee kinematics. QUESTIONS/PURPOSES: We hypothesized a more anatomic reconstruction of the medial femoral condyle, simultaneously preserving the tension of the PCL and medial collateral ligament, resulted in (1) medial-pivot rotation and tibial internal rotation, (2) lateral femoral rollback, and (3) reduced liftoff. PATIENTS AND METHODS: We compared 10 patients who underwent CR-TKA using the new technique at their 1-year followup to a matched control group of nine patients using a traditional gap-balancing technique at their 2- to 4-year followup. All patients received lateral radiographs in extension and flexion, which we utilized for three-dimensional implant matching to calculate tibial internal rotation, lateral rollback, and lateral liftoff in extension and flexion. RESULTS: The new gap-balancing technique resulted in a median of 3.5° tibial internal rotation with 2.7-mm rollback of the lateral femoral condyle relative to the medial condyle in flexion, which was different from the control group. We found no differences in liftoff between the groups. CONCLUSIONS: The new technique resulted in tibial internal rotation with flexion and lateral rollback comparing the lateral to the medial condyle in flexion, but no differences in condylar liftoff. These preliminary results were comparable to published kinematic results of an asymmetric CR-TKA or medial-pivot CR-TKA but not to symmetric CR-TKA.

Microfabrication of a three-dimensional polycaprolactone thin-film scaffold for retinal progenitor cell encapsulation.

Retinal degenerations are the leading cause of irreversible visual disability among the adult population. Stem-cell-based therapy has the potential to preserve and restore vision in these conditions. In addition to replacing lost or diseased cells, transplanted cells may be able to rescue dying photoreceptors of the host retina. To fully realize the potential of these cells, improved methods for cell delivery are needed. Utilizing microfabrication processes, a novel biodegradeable thin-film cell encapsulation scaffold was developed in polycaprolactone (PCL) as a possible cell transplantation vehicle. Individual thin-film 2-2.5-D PCL layers (<10 µm thin) were structured with varying micro- and nano-geometries (protrusions, cavities, pores, particles) utilizing a modified spin-assisted solvent casting and melt templating technique. Thin-film layers were aligned and thermally bonded to form the 3-D cell encapsulation scaffold (<30 µm thin) and these were found to promote retinal progenitor cell (RPC) retention and provide appropriate permeability. The resulting scaffolds provide a novel platform for the delivery of cells to the outer retina that addresses critical biological constraints related to transplantation to this anatomical location.