Mark C. Snoddy

Mitochondrial Permeability Transition in Liver Ischemia and Reperfusion: Role of c-Jun N-Terminal Kinase 2

The mitochondrial permeability transition (MPT) mediates hepatic necrosis after ischemia and reperfusion (I/R). Here, we studied the role of c-Jun N-terminal kinase 2 (JNK2) in MPT-induced liver injury. Wildtype (WT) and JNK2 knockout (KO) mice underwent 70% liver ischemia for 1 hr followed by reperfusion for 8 hr, after which hepatocyte injury and animal survival was assessed. Compared with WT, JNK2 KO mice had 38% less alanine transaminase release and 39% less necrosis by histology. Survival out to 14 days was also greater in JNK2 KO mice (57% vs. 11%), and overall Kaplan-Meier survival was improved. No difference in apoptosis was observed. Intravital multiphoton microscopy of potential-indicating rhodamine 123 after reperfusion revealed depolarized mitochondria in 82% of WT hepatocytes, which decreased to 43% in JNK2 KO hepatocytes. In conclusion, JNK2 contributes to hepatocellular injury and death after I/R in association with increased mitochondrial dysfunction via the MPT.

Flexor Tendon Repair Rehabilitation Protocols: A Systematic Review

PURPOSE To systematically review various flexor tendon rehabilitation protocols and to contrast those using early passive versus early active range of motion. METHODS We searched PubMed and Cochrane Library databases to identify articles involving flexor tendon injury, repair, and rehabilitation protocols. All zones of injury were included. Articles were classified based on the protocol used during early rehabilitation. We analyzed clinical outcomes, focusing on incidence of tendon rupture and postoperative functional range of motion. We also analyzed the chronological incidence of published tendon rupture with respect to the protocol used. RESULTS We identified 170 articles, and 34 met our criteria, with evidence ranging from level I to level IV. Early passive motion, including both Duran and Kleinert type protocols, results included 57 ruptures (4%) and 149 fingers (9%) with decreased range of motion of 1598 tendon repairs. Early active motion results included 75 ruptures (5%) and 80 fingers (6%) with decreased range of motion of 1412 tendon repairs. Early passive range of motion protocols had a statistically significantly decreased risk for tendon rupture but an increased risk for postoperative decreased range of motion compared to early active motion protocols. When analyzing published articles chronologically, we found a statistically significant trend that overall (passive and active rehabilitation) rupture rates have decreased over time. CONCLUSIONS Analyzing all flexor tendon zones and literature of all levels of evidence, our data show a higher risk of complication involving decreased postoperative digit range of motion in the passive protocols and a higher risk of rupture in early active motion protocols. However, modern improvements in surgical technique, materials, and rehabilitation may now allow for early active motion rehabilitation that can provide better postoperative motion while maintaining low rupture rates.

Upper Extremity Myonecrosis Caused by Edwardsiella Tarda Resulting in Transhumeral Amputation: Case Report

Necrotizing soft tissue infections are rapidly progressive infections with a high rate of mortality. One type of necrotizing soft tissue infection is caused by marine gram-negative bacteria and commonly occurs in immunocompromised hosts. These types of infections are more common in patients with chronic liver disease, possibly because of impaired iron metabolism. We present the case of a rapidly progressive necrotizing soft tissue infection caused by Edwardsiella tarda, a marine gram-negative pathogen common in catfish. Few extraintestinal infections of E tarda have been described previously. Our patient had hepatitis C and was exposed to the bacteria by a puncture injury from a wild catfish. His infection required multiple debridements and ultimately required a transhumeral amputation for local control of the infection.

Olecranon fractures: factors influencing re-operation

PurposeWe evaluated factors influencing re-operation in tension band and plating of isolated olecranon fractures.MethodsFour hundred eighty-nine patients with isolated olecranon fractures who underwent tension band (TB) or open reduction internal fixation (ORIF) from 2003 to 2013 were identified at an urban level 1 trauma centre. Medical records were reviewed for patient information and complications, including infection, nonunion, malunion, loss of function or hardware complication requiring an unplanned surgical intervention. Electronic radiographs of these patients were reviewed to identify Orthopaedic Trauma Association (OTA) fracture classification and patients who underwent TB or ORIF.ResultsOne hundred seventy-seven patients met inclusion criteria of isolated olecranon fractures. TB was used for fixation in 43 patients and ORIF in 134. No statistical significance was found when comparing complication rates in open versus closed olecranon fractures. In a multivariate analysis, the key factor in outcome was method of fixation. Overall, there were higher rates of infection and hardware removal in the TB compared with the ORIF group.ConclusionsOur results demonstrate that the dominant factor driving re-operation in isolated olecranon fractures is type of fixation. When controlling for all variables, there is an increased chance of re-operation in patients with TB fixation.

Intramedullary Nailing Compared with Spica Casts for Isolated Femoral Fractures in Four and Five-Year-Old Children

BACKGROUND Flexible intramedullary nailing (IMN) is a valuable tool in the treatment of femoral fractures in school-age children, whereas spica cast immobilization has been the standard of care for younger children. We compared these treatment modalities in a group of preschool-age children (four to five years of age). METHODS A retrospective cohort of consecutive patients, four to five years of age, with an isolated, complete femoral shaft or subtrochanteric fracture treated with intramedullary nailing or early spica cast immobilization and followed until fracture-healing were identified from two centers. Radiographic and clinical outcomes were compared between the groups. Statistical methods included chi-square and Fisher exact tests for categorical variables and the Mann-Whitney test for continuous variables. RESULTS Two hundred and sixty-two patients followed for a mean of thirty-two weeks were identified. One hundred and four patients underwent IMN and 158 patients were treated with immediate spica cast immobilization at the surgeons discretion. The patients who underwent IMN were older than those who underwent spica cast immobilization (mean, 5.2 versus 4.7 years; p < 0.001), were heavier (mean, 21.5 versus 18.0 kg; p < 0.001), and were more likely to have a higher-energy mechanism of injury (p = 0.025). At the time of final follow-up, there was no difference between groups with regard to the percentages of patients who had acceptable coronal angulation (≤15°), sagittal angulation (≤20°), and early fracture shortening (≤20 mm) (96.2% in the spica group versus 99.0% in the IMN group; p = 0.09). While there was no significant difference in the percentages who had an unplanned return to the operating room (3.8% in the IMN group versus 4.4% in the spica group; p > 0.99), the patients in the IMN group had more clinic visits (mean, 5.8 versus 4.0; p < 0.001) and longer follow-up (mean, forty-four versus twenty-five weeks; p < 0.001) than the patients in the spica group and a higher percentage of them underwent repeat procedures (89.4% versus 5.1%; p < 0.001), primarily for elective implant removal. CONCLUSIONS Preschool-age children (four to five years old) with an isolated femoral fracture have similar clinical and radiographic outcomes regardless of whether they are treated with immediate spica cast immobilization or IMN.

Charcot shoulder and elbow: a review of the literature and update on treatment

Charcot arthropathy of the shoulder and elbow is a rare disease process initially described in the 1700s; however, it was not until the 19th century that physicians understood its association with other disease processes such as cervical spine pathology and diabetes. A primary complaint is painful or painless joint dysfunction, meaning the orthopedic surgeon is regularly the first physician to evaluate the patient. Frequently, the condition of these patients is misdiagnosed. Although the pathogenesis of the disease is controversial, the etiology is commonly due to syringomyelia. The key to successful management is a thorough history and examination along with a workup including specific laboratory testing and imaging to rule out other disease processes. Most neuropathic shoulders and elbows have historically been managed conservatively because of poor outcomes with operative interventions. Newer data have emerged hinting that early neurosurgical intervention can stabilize this degenerative process. If clinical and radiographic stabilization occurs, recent studies have outlined surgical indications that can provide surgeons with a guide as to patients in whom successful operative outcomes can be achieved in the face of failed conservative management.

Biomechanical Strength of Scaphoid Partial Unions

Background It remains unknown how much force a partially united scaphoid can sustain without refracturing. This is critical in determining when to discontinue immobilization in active individuals. Purpose The purpose of this study was to test the biomechanical strength of simulated partially united scaphoids. We hypothesized that no difference would exist in load‐to‐failure or failure mechanism in scaphoids with 50% or more bone at the waist versus intact scaphoids. Materials and Methods Forty‐one cadaver scaphoids were divided into four groups, three experimental osteotomy groups (25, 50, and 75% of the scaphoid waist) and one control group. Each was subjected to a physiologic cantilever force of 80 to 120 N for 4,000 cycles, followed by load to failure. Permanent deformation during physiologic testing and stiffness, max force, work‐to‐failure, and failure mechanism during load to failure were recorded. Results All scaphoids survived subfailure conditioning with no significant difference in permanent deformation. Intact scaphoids endured an average maximum load to failure of 334 versus 321, 297, and 342 N for 25, 50, and 75% groups, respectively, with no significant variance. There were no significant differences in stiffness or work to failure between intact, 25, 50, and 75% groups. One specimen from each osteotomy group failed by fracturing through the osteotomy; all others failed near the distal pole loading site. Conclusion All groups behaved similarly under physiologic and load‐to‐failure testing, suggesting that inherent stability is maintained with at least 25% of the scaphoid waist intact. Clinical Relevance The data provide valuable information regarding partial scaphoid union and supports mobilization once 25% union is achieved.