Neonatal Enthesis Healing Involves Noninflammatory Acellular Scar Formation through Extracellular Matrix Secretion by Resident Cells.

Wound healing typically recruits the immune and vascular systems to restore tissue structure and function. However, injuries to the enthesis, a hypocellular and avascular tissue, often result in fibrotic scar formation and loss of mechanical properties, severely affecting musculoskeletal function and life quality. This raises questions about the healing capabilities of the enthesis. Herein, this study established an injury model to the Achilles entheses of neonatal mice to study the effectiveness of early-age enthesis healing. Histology and immunohistochemistry analyses revealed an atypical process that did not involve inflammation or angiogenesis. Instead, healing was mediated by secretion of collagen types I and II by resident cells, which formed a permanent hypocellular and avascular scar. Transmission electron microscopy showed that the cellular response to injury, including endoplasmic reticulum stress, autophagy, and cell death, varied between the tendon and cartilage ends of the enthesis. Single-molecule in situ hybridization, immunostaining, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays verified these differences. Finally, gait analysis showed that these processes effectively restored function of the injured leg. These findings reveal a novel healing mechanism in neonatal entheses, whereby local extracellular matrix secretion by resident cells forms an acellular extracellular matrix deposit without inflammation, allowing gait restoration. These insights into the healing mechanism of a complex transitional tissue may lead to new therapeutic strategies for adult enthesis injuries.

Diagnosis and Management of Infectious Arthritis in Children.

PURPOSE OF REVIEW: Septic arthritis is limb and life-threatening condition which necessitates rapid diagnosis and treatment. It is important for a medical practitioner to be familiar with this condition. This review summarizes the epidemiology, risk factors, diagnosis and differential diagnosis, complications, as well as treatment and the following-up of this condition. RECENT FINDINGS: Different causative organisms require unique diagnostic and treatment approaches. Establishing the diagnosis often requires multiple diagnostic modalities, some of which are new and innovative. Differential diagnosis requires excluding non-infectious inflammatory causes, such as reactive arthritis, juvenile rheumatoid arthritis, transient synovitis, and pericapsular pyomyositis. There is no consensus regarding the nature or duration of pharmacological or surgical treatment. Treatment includes administration of appropriate antimicrobial therapy and including the use of steroids and drainage. The most common complications are osteonecrosis of the femoral head and chronic osteomyelitis. Complications of septic arthritis are mostly due to a missed diagnosis. Further studies are required to better evaluate the diagnostic and therapeutic choice.

Anchor suture fixation of distal pole fractures of patella: twenty seven cases and comparison to partial patellectomy.

PURPOSE: Partial patellectomy (PP) and reattachment of the patellar ligament with transosseous suturing is the mainstay of surgical treatment for distal pole patellar fractures. An anchor suturing (AS) technique has recently been reported as an alternative to PP in such fractures and allows for bone-to-bone interface and possibly superior fracture healing than bone-to-tendon interface with PP. We present our experience with AS and compare it to PP. METHODS: Between 2006 and 2011, 60 patients with distal pole patellar fracture underwent either AS (n = 27) or PP (n = 33). We retrospectively gathered their demographic data and information on fracture type, fixation technique, operation time, postoperative complications and knee range of motion. A telephone survey was performed to grade functional outcomes with standard questionnaires (the SF-12 for quality of life, the Kujala score for patellofemoral function and a visual analog scale [VAS] pain score). RESULTS: AS was equivalent to PP in terms of residual pain and functional outcomes (VAS: 2.45 vs. 2.26, p = 0.83 and Kujala score: 74.3 vs. 69, p = 0.351, respectively) as well as for knee range of motion. Complications included three cases of infection in each group, two cases of early hardware failure and one case of non-union in the AS group. Operation time was significantly shorter for AS compared to PP (68.5 vs. 79.1 min, p = 0.03). CONCLUSIONS: AS is non-inferior to PP for function and pain after distal pole patellar fractures and is superior to PP with regard to operative time. Common complications of this technique are hardware failure and infections. LEVEL OF EVIDENCE: Therapeutic Level III.

Predictors for nonunion, reoperation and infection after surgical fixation of patellar fracture.

INTRODUCTION: The most common major complications following surgical fixation of patellar fractures are infection, nonunion and reoperation. In this study, we sought to define the predisposing factors to the development of these complications. METHODS: Open reduction and internal fixation surgeries for patellar fractures that were performed in a single institution between 2006 and 2011 were retrospectively reviewed. Patients' demographic data (age, gender, comorbidities), injury and fracture data (associated injuries, type of fracture, open or closed fracture), surgical data (type of surgery and interval between fracture occurrence and surgery) and major postoperative complications (infection, nonunion, symptomatic hardware and revision surgery) were collected from the medical records and verified by a telephone survey. Correlation analysis identified the major variables influencing the development of these complications. RESULTS: The cohort of 188 patients had an average follow-up of 908 days. Thirteen (6.9 %) patients developed infection, 3 (1.6 %) had fracture nonunion and 42 (22.3 %) required a second operation. A history of cerebrovascular accident (CVA) correlated significantly with the development of infection (OR 6.18, CI 1.1-35.6, p = 0.041) and nonunion (OR 14.9, CI 1.2-188.1; p = 0.037). A history of diabetes significantly increased the risk of a second operation (OR 8.69, CI 95 % 1.8-41.9, p = 0.007). Open fracture did not increase the risk of any of these complications. CONCLUSIONS: A history of CVA and diabetes mellitus significantly increased the risk of complications following patellar fracture fixation. Patients with these comorbidities should be informed of their increased risk of these complications and be followed up more rigorously.

The effects of 'old' red blood cell transfusion on mortality and morbidity in elderly patients with hip fractures--a retrospective study.

BACKGROUND: Elderly patients admitted with hip fractures often receive allogenic blood transfusion (ABT) in the perioperative period. We examined the effect of the shelf life of the ABT on mortality and morbidity. METHODS: A total of 1381 patients with hip fractures were retrospectively analysed. Two groups were compared, group A ('new'), with an ABT shelf life≤14 days, and group B ('old'), with an ABT shelf life>14 days. Data collected for both groups included general demographic data, data regarding postoperative infections and other complications rates and data regarding mortality. Kaplan-Meier curves were used to assess difference in survival between the groups. Cox regression was performed to analyse the survival after controlling for age, sex, pre-surgical haemoglobin concentration, pre-surgical creatinine, American Society of Anesthesiologists (ASA) score, surgery type and number of blood units given. RESULTS: Higher mortality was seen in hip fracture patients who received 'old' blood unit compared to 'new' blood unit but the difference was not statistically significant (P=0.5). Cox regression model demonstrated that designation into either young or old groups was not associated with mortality (hazard ratio: 1.14 (confidence interval: 0.85-1.53)). No differences were noted between the groups with regard to infection and other postoperative complication rates. CONCLUSION: Patients undergoing surgery for hip fractures who received 'old' units of blood did not differ from those receiving 'new' units with regard to mortality and morbidity. Large-scale clinical trials are needed to further investigate this association.