Chronological changes in the rate of surgical field contamination in the shoulder joint.

BACKGROUND: In shoulder surgery, low-virulence bacteria such as Cutibacterium acnes and coagulase-negative staphylococci can cause postoperative infection. However, the degree of sterility during surgery after disinfection is not known, and the efficacy of double skin preparation for such bacteria is unclear. This study aimed to evaluate chronological changes in the surgical field contamination rate in the shoulder joint and to compare single and double skin preparation. METHODS: In total, 126 shoulders in 121 patients undergoing shoulder surgery (64 men, 62 women; mean age 64 years) were enrolled. Patients were divided into two groups: single skin preparation, where the site was painted with 10% povidone iodine, and double skin preparation, where the site was treated with 1% chlorhexidine gluconate/83% isopropyl alcohol and painted 10% povidone iodine. Swab samples from the axillary and proximal areas in the surgical field were collected chronologically before starting surgery and at 30, 60, and 120 min after starting surgery (MAS). The contamination rate of each sample was compared and detected species were evaluated. RESULTS: The contamination rate for the axillary area was 48.4%, 85.9%, 95.3%, and 97.1% in the single-preparation group and 32.3%, 72.6%, 87.1%, and 91.2% in the double-preparation group before starting surgery and 30, 60, and 120 MAS, respectively, and that the proximal area was 12.5%, 26.6%, 29.7%, and 35.3% in the single-preparation group and 16.1%, 19.4%, 27.4%, and 38.2% in the double-preparation group, respectively. Significant differences were not seen between the groups by area or time point. Most detected species were Cutibacterium acnes and coagulase-negative staphylococci. CONCLUSIONS: The incidence of surgical field contamination in shoulder joint was high from immediately after starting surgery. In the axillary area, the contamination rates exceeded 70% from 30 MAS in both groups. Measures against infection should be instituted considering these findings when performing shoulder surgery.

Primary synovial chondromatosis of the shoulder followed for 11 years after arthroscopic surgery: A case report.

We report a case of primary synovial chondromatosis of the shoulder (Milgram classification, stage III) in a 25-year-old woman. She underwent arthroscopic removal of multiple loose bodies and partial synovectomy. Histological findings revealed primary synovial chondromatosis. Eleven years after surgery, the clinical results have been excellent with no recurrence, although X-ray showed slight degenerative changes of the glenohumeral joint. This is the first report of primary synovial chondromatosis of the shoulder observed over a 10-year follow-up period after arthroscopic surgery.

Signal intensity on MRI after conservative treatment of patients with full-thickness rotator cuff tears: Correlation with shoulder pain.

BACKGROUND: High signal intensity (HSI) on T2-weighted or fat-suppressed magnetic resonance imaging (MRI) around the shoulder is often observed in patients who have a rotator cuff tear, and is generally recognized as an indicator of shoulder pain, especially pain at night. We hypothesized these HSI volumes are reduced after improvement of symptoms. We sought to compare HSI before and after conservative treatment, and to determine if HSI is associated with the patient's pain status over time. METHODS: We enrolled 55 patients (average age 65 years) into the study. All the patients complained of pain at night (University of California, Los Angeles (UCLA) pain score ≤2, Japanese Orthopedic Association (JOA) pain score ≤10) at their initial visits and underwent conservative treatment. MRI was obtained at their initial visit and after improvement of pain when their initial UCLA pain score was ≥6 points or JOA pain score was ≥20 points. The mean time between the MRI examinations was 11.8 months (SD 7.7) (range 2.5-39). HSI was assessed at the location of the subacromial-subdeltoid bursa, glenohumeral joint, subcoracoid bursa, and sheath of the long head of the biceps tendon, and graded. Factors correlating with the improvement of MRI findings were evaluated retrospectively. RESULTS: HSI had improved in 30 shoulders in all or some of the locations (I-group). There was no change in 25 shoulders for any location or aggravation in one or more locations (N-group). Multivariate logistic regression analysis found that the time from pain improvement until the second MRI was the only independent factor related to the improvement in HSI (p = .045). CONCLUSION: Improvement of shoulder symptoms is not directly associated with MRI findings. Improvement in HSI followed symptom improvement after a delay; the changes varied for each shoulder location.

Distinctive collagen maturation process in fibroblasts derived from rabbit anterior cruciate ligament, medial collateral ligament, and patellar tendon in vitro.

PURPOSE: Differences in the tissue-specific collagen maturation process between tendon and ligament are still unknown. Collagen cross-link formation is crucial for the collagen maturation process. The aim of this study is to examine collagen maturation processes of anterior cruciate ligament (ACL), medial collateral ligament (MCL), and patellar tendon (PT) in vitro, in order to determine the optimal cell source for tissue engineering of ligament. METHODS: Cells derived from the ACL, MCL, and PT of New Zealand white rabbits were isolated. Each cell type was cultured for up to 4 weeks after reaching confluence. Cell-matrix layers were evaluated and compared for their morphology, collagen cross-links, and gene expression levels of lysine hydroxylase 1 and 2, lysyl oxidase (LOX), tenomodulin, collagen1A1 (Col1A1), and collagen3A1 (Col3A1). RESULTS: Transmission electron microscopy photomicrographs verified that collagen fibrils were secreted from all three types of fibroblasts. A higher ratio of dihydroxylysinonorleucine/hydroxylysinonorleucine was evident in the ligament compared to the tendon, which was consistent with lysine hydroxylase 2/lysine hydroxylase 1 gene expression. The gene expression of LOX, which regulates the total amount of enzymatic cross-linking, and the gene expression levels of Col1A1 and Col3A1 were higher in the ACL matrix than in the MCL and PT matrices. CONCLUSION: ACL, MCL, and PT cells have distinct collagen maturation processes at the cellular level. In addition, the collagen maturation of ACL cells is not necessarily inferior to that of MCL and PT cells in that all three cell types have a good ability to synthesize collagen and induce collagen maturation. This bioactivity of ACL cells in terms of ligament-specific mature collagen induction can be applied to tissue-engineered ACL reconstruction or remnant preserving procedure with ACL reconstruction.

Arthroscopic excision of bone fragments in a neglected fracture of the lateral process of the talus in a junior soccer player.

Fractures of the lateral process of the talus are uncommon and often overlooked. Typically, they are found in adult snowboarders. We report the case of an 11-year-old male soccer player who complained of lateral ankle pain after an inversion injury 6 months earlier. He did not respond to conservative treatment and thus underwent arthroscopic excision of fragments of the talar lateral process. The ankle was approached through standard medial and anterolateral portals. A 2.7-mm-diameter 30° arthroscope was used. Soft tissues around the talus were cleared with a motorized shaver, and the lateral aspect of the talar process was then visualized. The lateral process presented as an osseous overgrowth, and a loose body was impinged between the talus and the calcaneus. The osseous overgrowth was resected piece by piece with a punch, and the loose body was removed en block. The patient returned to soccer 5 weeks after the operation. This case exemplifies 2 important points: (1) This type of fracture can develop even in children and not only in snowboarders. (2) Arthroscopic excision of talar lateral process fragments can be accomplished easily, and return to sports can be achieved in a relatively short time.

Diabetes, collagen, and bone quality.

Diabetes increases risk of fracture, although type 2 diabetes is characterized by normal or high bone mineral density (BMD) compared with the patients without diabetes. The fracture risk of type 1 diabetes as well as type 2 diabetes increases beyond an explained by a decrease of BMD. Thus, diabetes may reduce bone strength without change in BMD. Whole bone strength is determined by bone density, structure, and quality, which encompass the micro-structural and tissue material properties. Recent literature showed that diabetes reduces bone material properties rather than BMD. Collagen intermolecular cross-linking plays an important role in the expression of bone strength. Collagen cross-links can be divided into beneficial enzymatic immature divalent and mature trivalent cross-links and disadvantageous nonenzymatic cross-links (Advanced glycation end products: AGEs) induced by glycation and oxidation. The formation pathway and biological function are quite different. Not only hyperglycemia, but also oxidative stress induces the reduction in enzymatic cross-links and the formation of AGEs. In this review, we describe the mechanism of low bone quality in diabetes and the usefulness of the measurement of plasma or urinary level of AGEs for estimation of fracture risk.

Incomplete joint side tear of the subscapularis tendon with a small fragment in an adolescent tennis player: a case report.

CASE: In this case report, we presented the case of an adolescent tennis player with avulsion injury of the subscapularis tendon of the right shoulder. PATIENTS: A 17-year-old right-hand-dominant male tennis player visited our hospital complaining of pain in the anterior aspect of the right shoulder. We performed X-ray and three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI) scans for the diagnosis. RESULTS: Plain radiographs did not reveal the presence of lesion; however, 3D-CT and MRI scans showed a small bony fragment located between the humeral head and the glenoid of the scapula and a high-intensity area of the subscapularis tendon. He was subsequently diagnosed with incomplete joint side tear of the subscapularis tendon with a small bony fragment. Subsequently, we performed arthroscopic excision of the bony fragment and repair of the subscapularis tendon. CONCLUSIONS: This case highlighted the presence of an injury with minor trauma associated with repeated tennis strokes in a skeletally immature patient.

Effects of alfacalcidol on mechanical properties and collagen cross-links of the femoral diaphysis in glucocorticoid-treated rats.

Bone fragility is increased in glucocorticoid (GC)-induced osteopenia even though GC-treated patients have higher bone mineral density (BMD), suggesting that the impaired bone quality may affect bone strength. This study was conducted to clarify the effects of GC on bone strength and collagen cross-links of adult rats and the effect of coadministration of alfacalcidol (ALF), a prodrug of active vitamin D(3). Six-month-old male Wistar-Imamichi rats (n = 32) were divided into the following four groups with equal average body weight: (1) 4-week age-matched controls, (2) 4-week GC (prednisolone, 10 mg/kg daily, i.m.) with concomitant administration of vehicle, (3) 4-week GC with concomitant administration of ALF (0.05 µg/kg daily, p.o.), and (4) 4-week GC with concomitant administration of ALF (0.1 µg/kg daily, p.o.). At the end of treatment, BMD, collagen cross-links, mechanical properties of the femoral midshaft, bone metabolic markers, and biochemical parameters were analyzed. In the GC group, femoral bone strength decreased without any change of BMD. This was accompanied by a decrease in the content of enzymatic cross-links. ALF (0.1 µg/kg) inhibited the GC-induced reduction in bone strength. The content of mature cross-links in the 0.1-µg/kg ALF group was significantly higher than that in the GC group. GC treatment caused a decrease in bone metabolic markers and serum calcium levels, which was counteracted by ALF coadministration. Preventive treatment with ALF inhibited the deterioration of bone mechanical properties primarily in association with the restoration of enzymatic cross-link formation and amelioration of the adverse effects of GC treatment on calcium metabolism.

The proteasome inhibitor bortezomib inhibits FGF-2-induced reduction of TAZ levels in osteoblast-like cells.

OBJECTIVES: Bortezomib (PS-341; Velcade), a proteasome inhibitor, is used as a therapeutic agent for multiple myeloma. Bortezomib has been shown to strongly induce osteoblast differentiation and elevate the levels of osteoblast-related differentiation markers in the serum of patients with myeloma. Bortezomib also reportedly increases the activity of the transcription factor, Runx2. However, the mechanism of action by which bortezomib-elevated Runx2 activity mediates osteoblast differentiation remains unclear. On the other hand, fibroblast growth factor 2 (FGF-2) is found at high levels in patients with multiple myeloma. We previously reported that FGF-2 reduces the levels of the transcriptional coactivator with PDZ-binding motif (TAZ). We therefore investigated the effects of bortezomib on TAZ protein levels in the presence of FGF-2. METHODS: Osteoblastic MC3T3-E1 cells were treated with different concentrations of bortezomib in the presence or absence of FGF-2 and various biologic responses were investigated by immunoblotting, RT-PCR, quantitative PCR, and alizarin red staining. RESULTS: We found that bortezomib inhibited FGF-2-induced reduction of TAZ levels through a pathway other than that used for proteasome inhibition, while maintaining TAZ function, which in turn, enhanced the expression of Runx2-transcribed osteogenic differentiation markers. Bortezomib also suppressed the antimineralization effect of FGF-2. CONCLUSIONS: These findings suggest that bortezomib inhibited FGF-2-induced reduction of TAZ and consequently stimulated osteogenic differentiation independently of proteasome inhibition. These findings may contribute to elucidate the osteolytic mechanism in multiple myeloma, and to the development of new drugs for multiple myeloma and other osteolytic diseases.