Biology and Biomechanics in Osteosynthesis of Proximal Humerus Fractures

Abstract Surgical treatment of proximal humeral fractures still remains a challenge. This is primarily due to the fact that sufficient implant fixation in humeral head fractures is often not achieved due to substantial bone tissue loss with increasing age. In the last few years the locking plates and locking nails have been introduced into clinical practice with varying results. The biomechanical studies have focused on locking plate osteosynthesis as well. The following paper focuses on bone quality, biomechanical studies and biology of proper osteosynthesis and reviews the most recent literature.     

Postmenopausal Women With Colles'' Fracture Have Lower Values of Bone Mineral Density Than Controls as Measured by Quantitative Ultrasound and Densitometry

Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density (BMD) to evaluate the probability of Colles' fracture. Two-hundred eighty-nine postmenopausal women (62.3 +/- 8.7 yr) with (n = 76) and without (n = 213) Colles' fracture were studied. BMD of lumbar spine and proximal femur was evaluated in all women by dual-energy X-ray absorptiometry (DXA) and speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness in the calcaneus were measured by a Sahara ultrasonometer (Hologic). Patients suffering from Colles' fracture had lower values of BMD adjusted by height at the lumbar spine, L2-L4 (0.797 g/cm2 vs 0.860 g/cm2), femoral neck (0.685 g/cm2 vs 0.712 g/cm2 ), SOS (1518 m/sg vs 1525 m/sg), and stiffness (74.6 vs 77.7) (p < 0.05). Nevertheless, BUA values were similar in both groups. After stepwise logistic regression analysis, the area found under receiver operating characteristic (ROC) curves was 0.60 for L2L4 and 0.63 for a formula combining L2L4 and height. Our data suggest that patients suffering from Colles' fracture have lower values of BMD by DXA, SOS, and stiffness. However, the ability of these techniques to discriminate is low because the values for the area under ROC curve are 0.60 for L2-L4 and 0.63 for a formula derived of the combination of L2-L4 and height.     

Warping of cross sections in the torsion of long bones with internal fracture fixation plates

Torsion of noncircular beams results in warping of each cross section. When noncircular cross sections are constrained to remain plane, the resulting shear stress distribution is different from what Saint Venant torsion (with warping) would predict. This has practical implications to the stress analysis of plated long bones subjected to torsional loadings. Analyses in which warping is not allowed predict incorrect stress fields in the plate and bone and overpredict the amount of stress shielding associated with fracture plate fixation.     

改良术式综合治疗陈旧性髌骨骨折

目的探讨陈旧性髌骨骨折的治疗方法。方法对11例陈旧性髌骨骨折进行回顾性总结,采用保留髌骨,切开复位,松解粘连,改良张力带钢丝或/和聚髌器坚强的内固定,术后配合CPM机康复锻炼。结果11例全部随访,随访0.5～4.5年,根据胥少汀等制定的评定标准,优4例,良5例,优良率81.8%。结论不做髌骨切除,松解粘连、良好的对位,坚强的内固定,早期配合应用CPM机进行功能锻炼,可取得满意的疗效。     

Adhesive fragment reattachment after orthodontic extrusion: a case report

Abstract –  In the treatment of crown fractures, adhesive fragment reattachment provides a good alternative to other restorative techniques, offering several advantages. The present paper reports a case in which the treatment of a cervical crown fracture was accomplished by reattaching the tooth fragment with a flowable resin composite. Orthodontic root extrusion was performed with a modified Hawley appliance prior to fragment reattachment. The clinical and radiographic results after 2.5 years were successful.     

多巴酚丁胺负荷超声心动图试验

对多巴酚丁胺负荷超声心动图试验诊断冠心病的理论基础、方法学及临床应用价值作一综述     

改良哈氏棒治疗胸腰段脊柱不稳定骨折

本文报告了作者研制的改良哈氏棒治疗胸腰段脊柱不稳定骨折的临床效果。１９９１年１月～１９９４年１０月，治疗２６例，伤椎椎体前缘高度从４１．９１％，恢复至９５．５７％，椎体后缘高度从８１．０３％恢复至１００％，后凸畸形（Ｃｏｂｂ氏法）从２６°恢复至５°，有５例恢复前凸８°～１０°，神经功能恢复１．８级（Ｆｒａｎｋｅｌ分级）。作者认为回复生理前凸的纵轴上纵向撑开力，更有助于胸腰段脊柱骨折的解剖复位。     

带旋髂深血管蒂髂骨瓣移植与加压螺钉治疗青壮年股骨颈骨折

本文报告了自１９８５年￣１９９５年间采用带旋髂深血管蒂髂骨瓣移植与加压螺纹钉内固定治疗青壮年囊内型股骨颈骨折２６例。随访时间平均５年５个月。结果，２６例骨折痊愈，骨折愈合率为１００％。骨折愈合时间平均４个月。仅１例骨折愈后后股骨头发生缺血坏死。股骨头缺血坏死率为４％。     

Open extremity fracture penetrating the skull

We present a case in which an open fracture of the ulna penetrated the skull and caused a comminuted, depressed skull fracture with a large intraparenchymal hematoma containing bone fragments.     

Reversal of stress-induced anhedonia by the dopamine receptor agonist,pramipexole

Chronic exposure to mild unpredictable stress has previously been found to depress the consumption of a palatable (1%) sucrose solution, and to attenuate food-induced place preference conditioning. In this study the effects of pramipexole (SND-919), a dopamine D₂ agonist, were studied during 7–9 weeks of chronic treatment. Pramipexole (1.0 mg/kg per day) reversed the suppression of sucrose intake in stressed animals, increasing sucrose intakes above the levels seen in untreated nonstressed controls. Pramipexole also increased sucrose intake in nonstressed animals; these effects were accompanied by increases in water intake and tended to correlate with weight loss. Drug-treated stressed animals also lost weight, but in this case water intake was unaffected. A second group of animals received a higher dose of pramipexole (2.0 mg/kg per day). The effects of the two doses were very similar. After three weeks of treatment, these animals were switched to a lower dose of pramipexole (0.1 mg/kg per day). Increases in sucrose intake were maintained over three weeks of treatment at the lower dose, with significant recovery of body weight. Two further groups received the same doses of pramipexole (1.0 mg/kg for 6 weeks or 2.0 mg/kg for 3 weeks followed by 0.1 mg/kg thereafter), but received intermittent (twice-weekly) drug treatment. Intermittent pramipexole treatments also tended to increase sucrose intakes, but the results were less consistent from week to week. Following 6–8 weeks of pramipexole treatment, food-induced place preference conditioning was studied in all animals. Untreated stressed animals showed no evidence of place conditioning. Normal conditioning was seen in both groups of stressed animals treated daily with pramipexole (at 1.0 and 0.1 mg/kg) and in the group treated twice weekly at the higher dose (1.0 mg/kg); intermittent treatment at the lower dose (0.1 mg/kg) was ineffective. The results indicate that pramipexole exerts rapid anti-anhedonic effects in the chronic mild stress model. This conclusion is complicated, but not undermined, by drug-induced weight loss and by the presence of significant drug effects in nonstressed control animals.