Signaling pathways in osteogenesis and osteoclastogenesis: Lessons from cranial sutures and applications to regenerative medicine.

One of the simplest models for examining the interplay between bone formation and resorption is the junction between the cranial bones. Although only roughly a quarter of patients diagnosed with craniosynostosis have been linked to known genetic disturbances, the molecular mechanisms elucidated from these studies have provided basic knowledge of bone homeostasis. This work has translated to methods and advances in bone tissue engineering. In this review, we examine the current knowledge of cranial suture biology derived from human craniosynostosis syndromes and discuss its application to regenerative medicine

The Purposes and Accountability of the Corporation in Contemporary Society: Corporate Governance at a Crossroads

Little attention has been paid to how the governance structures of public corporations adapt to structural changes in the social, political, economic and legal environments in which they operate. Bradley et al chronicle the recent changes in the conduct of business enterprise and establish the necessary conditions for a system of corporate governance capable of accommodating these changes

Earnings Volatility in America: Evidence from Matched CPS

We offer new evidence on earnings volatility of men and women in the United States over the past four decades by using matched data from the March Current Population Survey. We construct a measure of total volatility that encompasses both permanent and transitory instability, and that admits employment transitions and losses from self employment. We also present a detailed decomposition of earnings volatility to account for changing shares in employment probabilities, conditional variances of continuous workers, and conditional mean variances from labor-force entry and exit. Our results show that earnings volatility among men increased by 15 percent from the early 1970s to mid 1980s, while women’s volatility fell, and each stabilized thereafter. However, this pooled series masks important heterogeneity in volatility levels and trends across education groups and marital status. We find that men’s earnings volatility is increasingly accounted for by employment transitions, especially exits, while the share of women’s volatility accounted for by continuous workers rose, each of which highlights the importance of allowing for periods of non-work in volatility studies

Intraoperative Indocyanine Green Laser Angiography in Pediatric Autologous Ear Reconstruction.

Skin flap vascularity is a critical determinant of aesthetic results in autologous ear reconstruction. In this study, we investigate the use of intraoperative laser-assisted indocyanine green angiography (ICGA) as an adjunctive measure of skin flap vascularity in pediatric autologous ear reconstruction. Twenty-one consecutive pediatric patients undergoing first-stage autologous total ear reconstruction were retrospectively evaluated. The first 10 patients were treated traditionally (non-ICGA), and the latter 11 patients were evaluated with ICGA intraoperatively after implantation of the cartilage construct and administration of suction. Relative and absolute perfusion units in the form of contour maps were generated. Statistical analyses were performed using independent sample Student t test. Statistically significant differences in exposure and infection were not found between the 2 groups. However, decreased numbers of surgical revisions were required in cases with ICGA versus without ICGA (P = 0.03), suggesting that greater certainty in skin flap perfusion correlated with a reduction in revision surgeries. In cases of exposure, we found an average lowest absolute perfusion unit of 14.3, whereas cases without exposure had an average of 26.1 (P = 0.02), thereby defining objective parameters for utilizing ICGA data in tailoring surgical decision making for this special population of patients. Defined quantitative parameters for utilizing ICGA in evaluating skin flap vascularity may be a useful adjunctive technique in pediatric autologous ear reconstruction

Operative management of partial-thickness tears of the proximal hamstring muscles in athletes.

BACKGROUND: Partial tears of the hamstring muscle origin represent a challenging clinical problem to the patient and orthopaedic surgeon. Although nonoperative treatment is frequently met with limited success, there is a paucity of data on the efficacy of surgical management for partial proximal hamstring tears in the active and athletic population. PURPOSE: To evaluate the results of an anatomic repair for partial tears of the hamstring muscle origin in athletes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The records of 17 patients with partial tears of the proximal hamstring origin were reviewed after institutional review board approval was obtained. All patients were treated with open debridement and primary tendon repair after failure of at least 6 months of nonoperative therapy. Clinical and operative records, radiographs, and magnetic resonance images were reviewed for all patients. A patient-reported outcomes survey was completed by 14 patients that included the Lower Extremity Functional Score (LEFS), Marx activity rating scale, custom LEFS and Marx scales, and subjective patient satisfaction scores. Early and late postoperative complications were recorded. RESULTS: There were 3 male and 14 female patients; their average age was 43 years (range, 19-64 years) and average follow-up was 32 months (range, 12-51 months). There were 2 collegiate athletes (field hockey, track), 14 amateur athletes (distance running, waterskiing, tennis), and a professional bodybuilder. Postoperative LEFS was 73.3 ± 9.9 (range, 50-80) and custom LEFS was 66.7 ± 17.0 (range, 37-80) of a maximum 80 points. The most commonly reported difficulty was with prolonged sitting and explosive direction change while running. The average Marx score was 6.5 ± 5.3 (range, 0-16) of a maximum 16, correlating with a greater return to recreational running activities in this patient cohort than regular participation in pivoting or cutting sports. Marx custom scores were 20 of a maximum 20 in all patients, demonstrating no disability in the operative extremity with activities of daily living. No patient underwent a subsequent surgery. One patient was not satisfied with the result and reported persistent symptoms during competitive distance running. All patients were able to return to their preoperative level of activity after surgery. CONCLUSION: Anatomic surgical treatment of partial proximal hamstring avulsions can lead to satisfactory functional outcomes, a high rate of return to athletic activity, and low complication rate. This procedure should be reserved for patients who have failed an extended course of nonoperative treatment, and the proximity of the sciatic nerve mandates a careful assessment of the risk-benefit ratio before surgery is undertaken

Management of Morel-Lavallee lesion of the knee: Twenty-seven cases in the National Football League

BACKGROUND: The Morel-Lavallee lesion is a closed degloving injury most commonly described in the region of the hip joint after blunt trauma. It also occurs in the knee as a result of shearing trauma during football and is a distinct lesion from prepatellar bursitis and quadriceps contusion. PURPOSE: To review the authors\u27 experience with Morel-Lavallee lesion of the knee in the elite contact athlete to construct a diagnostic and treatment algorithm. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-seven knees in 24 players were identified from 1 National Football League team\u27s annual injury database as having sustained a Morel-Lavallee lesion between 1993 and 2006. Their charts were retrospectively reviewed. RESULTS: The most common mechanism of injury was a shearing blow on the playing surface (81%). The most common motion deficit was active flexion (41%). The mean time for resolution of the fluid collection and achievement of full active flexion was 16.3 days. The mean number of practices missed was 1.5. The mean number of games missed was 0.1. Fourteen knees (52%) were treated successfully with compression wrap, cryotherapy, and motion exercises. Thirteen knees (48%) were treated with at least 1 aspiration, and 6 knees (22%) were treated with multiple aspirations for recurrent serosanguineous fluid collections. In 3 cases (11%), the Morel-Lavallee lesion was successfully treated with doxycycline sclerodesis after 3 aspirations failed to resolve the recurrent fluid collections; return to play was immediate thereafter in each case. CONCLUSION: In football, Morel-Lavallee lesion of the knee usually occurs from a shearing blow from the playing field. Diagnosis is confirmed when examination reveals a large suprapatellar area of palpable fluctuance. Elite athletes are typically able to return to practice and game play long before complete resolution of the lesion. Recurrent fluid collections can occur, necessitating aspiration in approximately half the cases for successful treatment. Recalcitrant fluid collections can be safely and expeditiously treated with doxycycline sclerodesis

Rotator cuff contusions of the shoulder in professional football players: Epidemiology and magnetic resonance imaging findings

BACKGROUND: No published reports have studied the epidemiology and magnetic resonance imaging findings associated with rotator cuff contusions of the shoulder in professional football players. PURPOSE: To determine a single professional football team\u27s incidence, treatment, and magnetic resonance imaging appearance of players sustaining rotator cuff contusions of the shoulder. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From 1999 to 2005, a North American professional football team\u27s injury records were retrospectively reviewed for athletes who had sustained a rotator cuff contusion of the shoulder during in-season participation. Those patients who had magnetic resonance imaging of the shoulder with a 1.5-Tesla magnet were reviewed by a musculoskeletal radiologist and graded according to the appearance and severity of clinical injury. RESULTS: Twenty-six players had a rotator cuff contusion. There was an average of 5.5 rotator cuff contusions per season (47% of all shoulder injuries). The predominant mechanism of injury was a direct blow in 70.3%. Magnetic resonance imaging findings included peritendon edema at the myotendinous junction, critical zone tendon edema, and subentheseal bone bruises. Treatment consisted of a protocol involving modalities and cuff rehabilitation in all patients. Six patients had persistent pain and weakness for a minimum of 3 days and were given a subacromial corticosteroid injection. Overall, 3 patients (11.4%) required later surgical treatment on the shoulder. CONCLUSION: Rotator cuff contusions accounted for nearly half of all shoulder injuries in the football players in this study. Magnetic resonance imaging is an extremely useful tool in determining severity of injury and integrity of the rotator cuff. The majority of athletes are able to return to sports with conservative treatment; a minority of shoulders might progress to more severe injuries such as rotator cuff tears

Functional results and outcomes after repair of proximal hamstring avulsions.

BACKGROUND: The purpose of this study was to assess postsurgical outcomes in active patients after primary repair of acute and chronic proximal hamstring tears. HYPOTHESIS: Surgical treatment of both acute and chronic proximal hamstring avulsion injuries would result in improved patient outcomes using validated outcome scores and a hamstring-specific questionnaire, and operative repair of these injuries results in excellent outcomes with a high level of patient satisfaction, pain relief, and return to function. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fifty-two patients who underwent proximal hamstring repair (26 male and 26 female; average age, 47.7 years) completed the Lower Extremity Functional Scale (LEFS), a custom LEFS, the Marx Activity Scale, a custom Marx scale, a proximal hamstring score (which combines the sum of the custom LEFS and Marx), and a proximal hamstring questionnaire with subjective questions. Forty patients were characterized as having acute repairs, and 12 patients had chronic repairs. All patients underwent surgical repair with 5 suture anchors on the ischial tuberosity through a transverse incision. The rehabilitation protocol was also similar with the use of a hip orthosis for 6 to 8 weeks, allowing progressive weightbearing and range of motion. RESULTS: The mean follow-up in our study was 33 months (range, 12-76 months). The mechanism of injury in 28 patients was eccentric hip flexion and knee extension in the ipsilateral knee typically caused by a slip and fall accident. One patient\u27s injury was caused by trauma to the proximal hamstring. In 23 patients, hamstring injuries were sports related. Overall, 51 (98%) were satisfied with their outcome after surgery. The LEFS, Marx, custom LEFS, custom Marx, and proximal hamstring scores for patients with acute injuries were 76.2, 10.0, 71.4, 20, and 91.7, respectively. For those with chronic injury, the scores were 71.5, 10.4, 70.8, 18.7, and 89.8, respectively. The scores were not statistically different for LEFS, Marx, custom LEFS, and proximal hamstring scores (P = .22, P = .6, P = .72, and P = .6, respectively). Patients with acute injury did have a greater custom Marx score (P = .001). Postoperatively, 5 patients (9.6%) had burning pain or numbness in the posterior thigh or foot, and 25 (48%) had at least some discomfort sitting. Thirty-five patients (67%) reported they could participate in strenuous activities at their latest follow-up. All patients estimated their strength recovery at ≥75%. CONCLUSION: Results of this study indicate successful outcomes for both acute and chronic repairs, although patients with the acute repairs had higher functional and hamstring scores, and estimated hamstring strength

Digital Transformation Normalization: Using Managerial Actions to Effectively Execute Digital Business Strategy

Technological developments are challenging incumbent organizations’ business models, increasing the need for the Top Management Teams (TMT) to initiate a Digital Transformation (DT). This requires a Digital Business Strategy (DBS), which is executed using Managerial Actions (MAs). However, DT success is low, and MAs do not address the complexity and digital leadership skills required to execute the DBS and embed DT into the organization (DT Normalization). To explore these MAs in the context of DBS execution and DT Normalization, we conducted seven in-depth case studies of Dutch incumbent firms in the process of implementing a DBS across a range of industries. Our findings identified eight granular Digital Managerial Dimensions (DMDs), and we have related them to the previously identified MAs. We also related the DMDs to DT Normalization, providing pathways from DBS execution to DT Normalization. Our research contributes to the TMT’s role in guiding the organization through DBS implementation