The Holstein-Lewis humerus shaft fracture in children: are they different from adults?

Spiral fractures in the distal third humerus shaft (Holstein-Lewis fracture pattern) have been associated with high risk of radial nerve palsy in adults and surgical treatment is recommended as the treatment of choice to remove the entrapped nerve from the fracture site. But this association and treatment approach has not been evaluated in pediatric humerus shaft fractures. In a retrospective study, 38 pediatric patients with Holstein-Lewis fracture configuration were identified after a review of radiographs of 1609 patients with humerus shaft fracture. Age at initial presentation, sex, mechanism of injury, side involved, presence of any associated injuries, neurovascular status, radial nerve status, fracture management, and any complications were noted. Thiry-three (86.8%) patients with mean age 10.1 ± 3.7 years were successfully treated by closed methods. Five patients (13.2%) with mean age 15.2 ± 2.6 years underwent surgical treatment. Contrary to adults, no children/adolescents had radial nerve palsy at presentation. Radiographic healing was acceptable in all cases at latest follow-up. Holstein-Lewis fracture behaves differently in children with no increased risk of radial nerve palsy. Majority can be treated conservatively. The thick periosteum in children may offer protection to the radial nerve and may be responsible for the success of closed treatment.

Cost-benefit analysis of routine pathology examination in primary shoulder arthroplasty.

BACKGROUND: The annual number of shoulder arthroplasty procedures is continuing to increase. Specimens from shoulder arthroplasty cases are routinely sent for pathologic examination. This study sought to evaluate the clinical utility and associated costs of routine pathologic examination of tissue removed during primary shoulder arthroplasty cases and to determine cost-effectiveness of this practice. METHODS: This is a retrospective review of primary shoulder arthroplasty cases. Patients whose humeral head was sent for routine pathologic examination were included. Cases were determined to have concordant, discrepant, or discordant diagnoses based on preoperative/postoperative diagnosis and pathology diagnosis. Costs were estimated in 2015 U.S. dollars, and cost-effectiveness was determined by the cost per discrepant diagnosis and cost per discordant diagnosis. RESULTS: We identified 714 cases of primary shoulder arthroplasty in 646 patients who met inclusion criteria. The prevalence of concordant diagnoses was 94.1%, the prevalence of discrepant diagnoses was 5.9%, and no cases had discordant diagnoses. There were 172 cases that had biceps tendon specimens sent for pathology examination, and none led to a change in patient care. Total estimated costs were $77,309.34 in 2015 U.S. dollars. Cost per discrepant diagnosis for humeral head specimens was $1424.09, and cost per discordant diagnosis is at least $59,811.78. DISCUSSION/CONCLUSION: Primary shoulder arthroplasty has a high rate of concordant diagnosis. Discrepant diagnoses were 5.9% in our study, and there were no discordant diagnoses. This study showed limited clinical utility in routinely sending specimens from primary shoulder arthroplasty cases for pathology examination, and calculation using a traditional life-year value of $50,000 showed that the standard for cost-effectiveness is not met.

Natural History of Adolescent Idiopathic Scoliosis in Skeletally Mature Patients: A Critical Review.

The surgical treatment of adolescent idiopathic scoliosis is dependent on several factors, including curve type and magnitude, degree of curve progression, skeletal maturity, and other considerations, such as pain and cosmesis. The most common indication for surgery is curve progression. Most authors agree that surgical treatment should be considered in skeletally mature patients with curves > 50° because of the risk of progression into adulthood. Furthermore, most authors would agree that curves measuring < 40° to 45° in skeletally mature patients should be observed. When a skeletally mature patient with a curve measuring between 45° to 55° is presenting to an orthopaedic surgeon, it is not uncommon that the patient has no pain, no progression, and no imbalance. The generally accepted belief has been that curves that reach 50° are likely to progress into adulthood, progressing at a rate of 1° per year, based largely on the Iowa studies. However, the level of evidence for this is relatively weak, and the existing literature is equivocal in supporting the practice of performing surgery on these patients.

Prospective Randomized Comparison of Locked Plates Versus Nonlocked Plates for the Treatment of High-Energy Pilon Fractures.

OBJECTIVES: To compare the radiographic and functional outcome of patients with high-energy pilon fractures treated with locked versus nonlocked plates. DESIGN: Randomized prospective trial. SETTING: Academic level 1 trauma center. PATIENTS: Between December 2006 and December 2008, 60 consecutive patients with 62 AO/OTA type A, B, and C tibial pilon fractures were enrolled in the study. Thirty-two of the fractures were treated using locked plates and 29 were treated with nonlocked plates. Follow-up data were available for 33 of the 60 patients. INTERVENTION: Treatment with locked versus nonlocked plates. MAIN OUTCOME MEASURES: Short Musculoskeletal Function Assessment (SMFA) questionnaire and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale (AHS). Radiographic measurements on anteroposterior and lateral views for the quality of reduction and maintenance of alignment immediately postoperatively compared with the latest follow-up. RESULTS: There were no significant differences in the mechanism or injury pattern, average age of the patients, ratio of males to females, tourniquet time, operative time, interval to surgery, AHS, or SMFA scores. One of 15 fractures in the locked plate group lost reduction at the latest follow-up compared with 3 of 19 fractures in the nonlocked group. CONCLUSIONS: In this study, there seems to be no difference between the 2 constructs. Thus, one must question the routine use of locked plates in the treatment of high-energy pilon fractures. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Improved biomechanical and biological outcomes in the MRL/MpJ murine strain following a full-length patellar tendon injury.

Musculoskeletal injuries greatly affect the U.S. population and current clinical approaches fail to restore long-term native tissue structure and function. Tissue engineering is a strategy advocated to improve tendon healing; however, the field still needs to establish biological benchmarks for assessing the effectiveness of tissue-engineered structures. Investigating superior healing models, such as the MRL/MpJ, offers the opportunity to first characterize successful healing and then apply experimental findings to tissue-engineered therapies. This study seeks to evaluate the MRL/MpJ's healing response following a central patellar tendon injury compared to wildtype. Gene expression and histology were assessed at 3, 7, and 14 days following injury and mechanical properties were measured at 2, 5, and 8 weeks. Native patellar tendon biological and mechanical properties were not different between strains. Following injury, the MRL/MpJ displayed increased mechanical properties between 5 and 8 weeks; however, early tenogenic expression patterns were not different between the strains. Furthermore, expression of the cyclin-dependent kinase inhibitor, p21, was not different between strains, suggesting an alternative mechanism may be driving the healing response. Future studies will investigate collagen structure and alignment of the repair tissue and characterize the complete healing transcriptome to identify mechanisms driving the MRL/MpJ response.

The paratenon contributes to scleraxis-expressing cells during patellar tendon healing.

The origin of cells that contribute to tendon healing, specifically extrinsic epitenon/paratenon cells vs. internal tendon fibroblasts, is still debated. The purpose of this study is to determine the location and phenotype of cells that contribute to healing of a central patellar tendon defect injury in the mouse. Normal adult patellar tendon consists of scleraxis-expressing (Scx) tendon fibroblasts situated among aligned collagen fibrils. The tendon body is surrounded by paratenon, which consists of a thin layer of cells that do not express Scx and collagen fibers oriented circumferentially around the tendon. At 3 days following injury, the paratenon thickens as cells within the paratenon proliferate and begin producing tenascin-C and fibromodulin. These cells migrate toward the defect site and express scleraxis and smooth muscle actin alpha by day 7. The thickened paratenon tissue eventually bridges the tendon defect by day 14. Similarly, cells within the periphery of the adjacent tendon struts express these markers and become disorganized. Cells within the defect region show increased expression of fibrillar collagens (Col1a1 and Col3a1) but decreased expression of tenogenic transcription factors (scleraxis and mohawk homeobox) and collagen assembly genes (fibromodulin and decorin). By contrast, early growth response 1 and 2 are upregulated in these tissues along with tenascin-C. These results suggest that paratenon cells, which normally do not express Scx, respond to injury by turning on Scx and assembling matrix to bridge the defect. Future studies are needed to determine the signaling pathways that drive these cells and whether they are capable of producing a functional tendon matrix. Understanding this process may guide tissue engineering strategies in the future by stimulating these cells to improve tendon repair.

Treatment of protrusio fractures of the acetabulum in patients 70 years and older.

OBJECTIVE: To present clinical, radiographic, and functional outcomes in patients 70 years and older with a protrusio-type acetabulum fracture. DESIGN: Retrospective case series. SETTING: Two level 1 trauma centers. PATIENTS: Between November 2000 and December 2009, 39 consecutive patients older than 70 years with protrusio acetabulum fractures were enrolled. INTERVENTION: Open reduction internal fixation using a combination of pelvic brim and infrapectineal plates. MAIN OUTCOME MEASUREMENTS: Clinical, radiographic, and functional outcomes as assessed with the modified Merle d'Aubigné score. RESULTS: Twelve patients were lost to follow-up (<12 months), and one patient was excluded from analysis because he was treated with a percutaneous technique. The remaining 26 (67%) had a mean follow-up of 34 months (12-127 months). At the final follow-up, radiographic grades were excellent in 15, good in 3, poor in 3, and 5 patients had a total hip arthroplasty (19%) at an average of 18 months after the index procedure .The average modified Merle d'Aubigné score was 16 (9-18); categorized as excellent in 10, very good in 4, good in 7, fair in 2, and poor in 3. CONCLUSION: In the senior patient with a protrusio acetabulum fracture, a treatment strategy that optimizes preoperative conditions, minimizes operative time and blood loss, achieves a stable concentric hip joint, and encourages immediate postoperative ambulation can result in reasonable clinical, radiographic, and functional outcomes with acceptable morbidity. This appears to remain true even in the face of a less than anatomic reduction. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The relationships among spatiotemporal collagen gene expression, histology, and biomechanics following full-length injury in the murine patellar tendon.

Tendon injuries are major orthopedic problems that worsen as the population ages. Type-I (Col1) and type-II (Col2) collagens play important roles in tendon midsubstance and tendon-to-bone insertion healing, respectively. Using double transgenic mice, this study aims to spatiotemporally monitor Col1 and Col2 gene expression, histology, and biomechanics up to 8 weeks following a full-length patellar tendon injury. Gene expression and histology were analyzed weekly for up to 5 weeks while mechanical properties were measured at 1, 2, 5, and 8 weeks. At week 1, the healing region displayed loose granulation tissue with little Col1 expression. Col1 expression peaked at 2 weeks, but the ECM was highly disorganized and hypercellular. By 3 weeks, Col1 expression had reduced and by 5 weeks, the ECM was generally aligned along the tendon axis. Col2 expression was not seen in the healing midsubstance or insertion at any time point. The biomechanics of the healing tissue was inadequate at all time points, achieving ultimate loads and stiffnesses of 48% and 63% of normal values by 8 weeks. Future studies will further characterize the cells within the healing midsubstance and insertion using tenogenic markers and compare these results to those of tendon cells during normal development.

Immediate full weightbearing after percutaneous fixation of anterior column acetabulum fractures.

OBJECTIVE: To present clinical, radiographic, and functional outcomes of patients allowed immediate full weightbearing after closed reduction and percutaneous fixation of anterior column component acetabulum fractures. DESIGN: Retrospective review. SETTING: Academic Level I trauma center. PATIENTS: Between September 2001 and December 2008, 28 patients with anterior column or anterior column posterior hemitransverse acetabulum fractures that were determined to be amenable to percutaneous fixation (at the discretion of the senior author [M.T.A.]) were selected. INTERVENTION: All patients underwent closed reduction and anterior to posterior supra-acetabular percutaneous screw fixation followed by immediate postoperative full weightbearing. MAIN OUTCOME MEASUREMENTS: Primary outcome measures included clinical, radiographic, and functional outcomes assessed with the modified Merle d'Aubigne Score and the Short Musculoskeletal Function Assessment questionnaire. RESULTS: Six patients were lost to follow-up (less than 1 year), and the remaining 22 (79%) had a mean follow-up of 39 months (range, 12-74 months). There were no intraoperative complications. Radiographic grades were excellent in 19 patients, good in two patients, and fair in one patient. The mean modified Merle d'Aubigné Score was 17.4 (range, 11-18). The mean Short Musculoskeletal Function Assessment function and bothersome index were 20.2 (range, 0-72.8) and 20.1 (range, 0-72.9), respectively. CONCLUSION: Clinical, radiographic, and functional outcomes of patients in this study are comparable to other reported studies. Despite an immediate full weightbearing protocol, complications, particularly poor final radiographic grade, do not appear common. The advantage of this protocol lies in the ability to immediately ambulate postoperatively with early return to work and recreation. We believe this technique is safe and offers a reasonable alternative for anterior column acetabulum fractures.

Reaming as an adjuvant to irrigation on bacterial presence and propagation: an open, cadaveric intramedullary fracture model.

OBJECTIVES: The purpose of this investigation is to evaluate the effect of intramedullary reaming on bacterial presence and propagation in an open, cadaveric intramedullary fracture model. METHODS: Twelve fresh-frozen human cadaveric femurs were osteotomized and inoculated with Staphylococcus aureus, the open, cadaveric intramedullary fracture model. Low-pressure pulsed lavage irrigation was performed to irrigate the osteotomy sites. The specimens were divided into two groups of six paired specimens: CNT, irrigation only; and REAM, irrigation coupled with intramedullary reaming. Intramedullary contents were cultured at the osteotomy site and in 1-cm increments through the distal femoral metaphysis. Mean bacterial colony-forming units were compared between groups using analysis of variance. RESULTS: A statistically significant higher bacterial colony-forming unit count was noted at the osteotomy site (bacterial presence) in the CNT group compared with the REAM group. In terms of bacterial propagation, when compared with the sterile osteotomy site, the CNT group demonstrated significant bacterial propagation only at the 1.1- to 2.0-cm increment and the REAM group demonstrated no significant propagation. In comparing bacterial propagation between the CNT and the REAM groups, no significant differences were noted at any distal increment. CONCLUSION: In this open, cadaveric intramedullary fracture model, low-pressure pulse lavage coupled with intramedullary reaming demonstrated significantly less bacterial presence at the osteotomy site compared with irrigation without reaming. Additionally, intramedullary reaming does not appear to significantly propagate bacteria into the intramedullary canal nor into the distal metaphysis. These observations might have clinical significance.

Interfacial polar interactions affect gramicidin channel kinetics.

Critical to biological processes such as secretion and transport, protein-lipid interactions within the membrane and at the membrane-water interface still raise many questions. Here we examine the role of lipid headgroups in these interactions by using gramicidin A (gA) channels in planar bilayers as a probe. We show that although headgroup demethylation from phosphatidylcholine (DOPC) to phosphatidylethanolamine decreases the lifetime of gA channels by an order of magnitude in accordance with the currently accepted hydrophobic mismatch mechanism, our findings with diether-DOPC suggest the importance of the headgroup-peptide interactions. According to our x-ray diffraction measurements, this lipid has the same hydrophobic thickness as DOPC but increases gA lifetime by a factor of 2. Thus we demonstrate that peptide-headgroup interactions may dominate over the effect of hydrophobic mismatch in regulating protein function.

Voltage gating of VDAC is regulated by nonlamellar lipids of mitochondrial membranes.

Evidence is accumulating that lipids play important roles in permeabilization of the mitochondria outer membrane (MOM) at the early stage of apoptosis. Lamellar phosphatidylcholine (PC) and nonlamellar phosphatidylethanolamine (PE) lipids are the major membrane components of the MOM. Cardiolipin (CL), the characteristic lipid from the mitochondrial inner membrane, is another nonlamellar lipid recently shown to play a role in MOM permeabilization. We investigate the effect of these three key lipids on the gating properties of the voltage-dependent anion channel (VDAC), the major channel in MOM. We find that PE induces voltage asymmetry in VDAC current-voltage characteristics by promoting channel closure at cis negative applied potentials. Significant asymmetry is also induced by CL. The observed differences in VDAC behavior in PC and PE membranes cannot be explained by differences in the insertion orientation of VDAC in these membranes. Rather, it is clear that the two nonlamellar lipids affect VDAC gating. Using gramicidin A channels as a tool to probe bilayer mechanics, we show that VDAC channels are much more sensitive to the presence of CL than could be expected from the experiments with gramicidin channels. We suggest that this is due to the preferential insertion of VDAC into CL-rich domains. We propose that the specific lipid composition of the mitochondria outer membrane and/or of contact sites might influence MOM permeability by regulating VDAC gating.