Study Design Retrospective chart analysis of 199 individuals aged 18-80 years scheduled for lumbar spine surgery. Objective The purpose of this study was to quantify changes in muscle cross sectional area (CSA) and fat signal fraction (FSF) with age in men and women with lumbar spine pathology and compare them to published normative data. Summary of Background Data Pathological changes in lumbar paraspinal muscle are often confounded by age-related decline in muscle size (CSA) and quality (fatty infiltration). Individuals with pathology have been shown to have decreased CSA and fatty infiltration of both the multifidus and erector spinae muscles, but the magnitude of these changes in the context of normal aging is unknown. Methods Individuals aged 18-80 years who were scheduled for lumbar surgery for diagnoses associated with lumbar spine pain or pathology were included. Muscle CSA and FSF of the multifidus and erector spinae were measured from preoperative T2-weighted magnetic resonance images at the L4 level. Univariate and multiple linear regression analyses were performed for each outcome using age and gender as predictor variables. Statistical comparisons of univariate regression parameters (slope and intercept) to published normative data were also performed. Results There was no change in CSA with age in either gender (p>0.05), but women had lower CSA's than men in both muscles (p<0.0001). There was an increase in FSF with age in erector spinae and multifidus muscles in both genders (p<0.0001). Multifidus FSF values were higher in women with lumbar spine pathology than published values for healthy controls (p=0.03), and slopes tended to be steeper with pathology for both muscles in women (p<0.08) but not in men (p>0.31). Conclusions Lumbar muscle fat content, but not CSA changes with age in individuals with pathology. In women, this increase is more profound than age-related increases in healthy individuals.

Histological and cell-level changes in the lumbar musculature in individuals with chronic lumbar spine degenerative conditions are not well characterized. Although prior literature supports evidence of changes in fiber type and size, little information exists describing the tissue quality and biology of pathological features of muscle in this population. The purpose of this study was to quantify multifidus tissue composition and structure, inflammation, vascularity, and degeneration in individuals with chronic degenerative lumbar spine pathology. Human multifidus biopsies were acquired from 22 consecutive patients undergoing surgery for chronic degenerative lumbar spine pathology. Relative fractions of muscle, adipose, and extracellular matrix were quantified along with muscle fiber type and cross-sectional area (CSA) and markers of inflammation, vascularity, satellite cell density, and muscle degeneration. On average, multifidus biopsies contained 48.5% muscle, 11.7% adipose tissue, and 26.1% collagen tissue. Elevated inflammatory cell counts (48.5 ± 30.0 macrophages/mm2) and decreased vascularity (275.6 ± 69.4 vessels/mm2) were also observed compared to normative values. Satellite cell densities were on average 13 ± 9 cells per every 100 muscle fibers. Large fiber CSA (3,996.0 ± 1,909.2 um2) and a predominance of type I fibers (61.8 ± 18.0%) were observed in addition to evidence of pathological degeneration-regeneration cycling (18.8 ± 9.4% centrally nucleated fibers, and 55.2 ± 24.2% of muscle regions containing degeneration). High levels of muscle degeneration, inflammation, and decreased vascularity were commonly seen in human multifidus biopsies of individuals with lumbar spine pathology in comparison to normative data. Evidence of active muscle degeneration suggests that changes in muscle tissue are more complex than simple atrophy.

* Careful scrutiny of radiographs is important in the assessment of pediatric elbow injuries. Disruption of the radiocapitellar line and an increased bow of the posterior ulnar border are sometimes subtle signs of a Monteggia injury.* An attempt at closed reduction up to 4 weeks after injury has been cited in the literature as successfully treating some missed injuries.* Operative reduction of chronic radial-head dislocation provides good to excellent range of motion and functional outcome in the setting of irreducible chronic radial-head dislocation.* Ulnar osteotomy and correction of the ulnar deformity component of the missed Monteggia injury are the key to indirect anatomic reduction of the radiocapitellar joint.* Supplemental procedures aimed at increasing the stability of the radiocapitellar joint (e.g., annular ligament reconstruction, radiocapitellar Kirschner wire fixation, radioulnar Kirschner wire fixation) should be directed by a thorough assessment of radiocapitellar stability following ulnar osteotomy and correction of the ulnar deformity.

Modular neck femoral stems have been associated with adverse local tissue reactions (ALTR), leading to a voluntary recall, but these effects have not been well-characterized. A retrospective review of intraoperative findings and cobalt/chromium levels was performed in 103 hips undergoing revision for ALTR. The average preoperative serum cobalt level was 7.6 μg/L (range 1.1-23 μg/L) and chromium level was 1.8 μg/L (range 0.1-6.8 μg/L). Metallic sludge was noted in 100%, synovitis in 98%, pericapsular rind in 82%, and calcar erosion in 85%. An osteotomy was required for removal in 44%. We concluded that revision of modular neck femoral stems is associated with increased preoperative metal ion levels and stem-neck corrosion. Despite advanced stem explantation techniques, osteotomy was frequently required, leading to increased morbidity.