Dual Hip Bone Mineral Density in Postmenopausal Women: Geometry and Effect of Physical Activity

The objectives of this study were to (1) obtain both femoral neck strength (FNS) and hip axis length (HAL) values from left and right femurs (regardless of hip dominance) measured by DXA and evaluate their relationship with BMD of all hip regions including total hip, (2) determine if there is a difference between dominant and nondominant hip BMD in any of the hip regions, and (3) determine how physical activity influences hip BMD. Participants were 136, generally healthy Caucasian women (57.4–88.6 years). BMD was measured by DPX-MD. Past and present activity was assessed by the Allied Dunbar National Fitness Survey for older adults and normal/brisk walking pace was measured in a straight hallway. FNS analysis uses femoral geometry to calculate stresses at the femoral neck for two loading conditions: Safety Factor Index (SF) indicates risk of fracture for forces generated during a one-legged stance, and Fall Index (FI) indicates risk of fracture for forces generated during a fall on the greater trochanter. Simple and multiple regression analyses were used to determine predictive ability of HAL, SF, and FI for respective hip BMD values. There was no statistical difference in BMD between two hips in any of the measured regions, however, the nondominant hip correlated better with other skeletal sites. Subjects with a faster normal walking speed had higher neck BMD in the nondominant hip, 0.832 ± 0.12 vs. 0.791 ± 0.10 g/cm² (P < 0.05). Longer HAL of the left hip was negatively related to neck, trochanter, shaft, and total hip BMD. FI was significantly associated with all sites of the hip BMD, while SF was associated only with neck and wards BMC (P < 0.05). In summary: (1) a longer HAL is associated with lower BMD and a higher FI with higher BMD, (2) it might be sufficient to measure BMD in only the nondominant hip, and (3) walking at a faster pace may positively benefit femoral neck BMD. Therefore, it appears that HAL, SF, and FI all play important roles in estimating fracture risk and should be assessed along with BMD when using DXA.     

可吸收钉棒内固定治疗股骨头、髋臼骨折

目的 应用可吸收钉棒(SR-PLLA)内固定治疗10例股骨头骨折、髋臼骨折的疗效。方法 本组病例中,4例股骨头骨折,4例髋臼后缘骨折,两者合并存在2例,术前9例合并髋关节后脱位,1例合并骶骼关节开放性脱位。均经髋关节后外侧或后路切开复位可吸收螺钉及固定棒固定,术后持续骨牵引6周,并主动下肢屈髋活动。结果 随访平均14.5个月,按髋关节功能评定标准:优6例,良3例,可1例,术后一年发生股骨头缺血性坏死1例,无感染、骨折移位、关节僵硬等并发症发生。结论 SR-PLLA内固定是治疗股骨头骨折、髋臼骨折的理想方法。     

Genesis Ⅱ与PFC两种假体全膝关节置换术后膝前痛的比较研究

目的 探讨全膝关节置换术后膝前痛与髌骨置换及假体设计的关系,GenesisⅡ与PFC两种股骨假体与髌骨之间的友好性.方法 回顾性分析由同一组高年资医生施行初次全膝关节置换术的145例(145膝)骨关节炎患者的临床资料.均采用后十字韧带替代型全膝关节假体,髌骨置换74例,其中32例使用GenesisⅡ假体、42例使用PFC假体;髌骨未置换71例,其中38例使用GenesisⅡ假体、33例使用PFC假体.术后评估美国特种外科医院(Hospital for Special Surgery,HSS)膝关节评分、髌骨评分、髌骨功能评分、膝关节活动度、膝前痛评分、满意度和X线片上髌骨倾斜和半脱位情况.结果 随访144例,随访时间21～43个月,平均33个月.术后膝前痛发生率:髌骨置换组与未置换组的差异无统计学意义,组内使用GenesisⅡ假体与PFC假体的差异有统计学意义.使用PFC假体者4例再次手术.功能评分:髌骨置换组及髌骨未置换组中使用GenesisⅡ假体与PFC假体术后HSS评分、活动度、满意度的差异均无统计学意义,而术后髌骨评分及髌骨功能评分的差异有统计学意义.结论 术后膝前痛的发生率与是否置换髌骨无关,而与假体设计有关;GenesisⅡ假体与髌骨的关系更加友好.     

The Conversion Rate of Bipolar Hemiarthroplasty after a Hip Fracture to a Total Hip Arthroplasty

Background

Bipolar hip hemiarthroplasty is used in the management of fractures of the proximal femur. The dual articulation is cited as advantageous in comparison to unipolar prostheses as it decreases acetabular erosion, has a lower dislocation rates and is easier to convert to a total hip arthroplasty (THA) should the need arise. However, these claims are debatable. Our study examines the rate of conversion of the bipolar hemiarthroplasty to THA and the justification for using it on the basis of future conversion to THA.

Methods

All cases of bipolar hemiarthroplasty performed in our unit for hip fractures over a 9-year period (1999-2007) were reviewed. Medical notes and radiographs of all patients were reviewed, and all surviving patients that were contactable received a telephone follow-up.

Results

Of all 164 patients reviewed with a minimum of 1 year from date of surgery, 4 patients had undergone a conversion of their bipolar prosthesis to THA. Three conversions were performed for infection, dislocation, and fracture. Only one (0.6%) conversion was performed for groin pain.

Conclusions

Our study show that bipolar hemiarthroplasties for hip fractures have a low conversion rate to THAs and this is comparable to the published conversion rate of unipolar hemiarthroplasties.     

动力髋螺钉与股骨近端防旋髓内钉治疗骨质疏松性股骨转子间骨折的有限元比较研究

目的 建立骨质疏松性改良Evans分型Ⅲ型股骨转子间骨折的有限元模型,比较动力髋螺钉(DHS)和股骨近端防旋髓内钉(PFNA)内固定在不同表观骨密度和载荷下的生物力学特性. 方法 选择1例改良Evans分型为Ⅲ型的老年股骨转子间骨折患者,男性,年龄为75岁,身高172 cm,体质量为70 kg.对患者股骨中上2/3段进行CT扫描,建立骨折模型并予虚拟复位,分别在此模型上搭载DHS(模型Ⅰ组)和PFNA(模型Ⅱ组)两种内固定物.每组分别考虑7种表观骨密度(70％、80％、90％、100％、110％、120％、130％的表观骨密度)及3种载荷(0.5、1.0、3.0倍体质量)下的受力情况,共有42种工况.比较各种条件下两组固定模型的股骨Von Mises应力峰值、内固定物Von Mises应力峰值及股骨单元失效率. 结果 在同一载荷下,模型Ⅰ组股骨及内固定物所承受应力、股骨单元失效率均大于模型Ⅱ组,差异有统计学意义(P＜0.05);同一模型随着载荷的增加,股骨及内固定物所承受的应力、股骨单元失效率均上升,差异有统计学意义(P＜0.05).在3.0倍体质量载荷、70％表观骨密度下,模型Ⅰ组和模型Ⅱ组的股骨最大应力值分别为84.702、38.986 MPa,内固定物最大应力值分别为952.557、580.134 MPa,股骨单元失效率分别为3.25％、7.99×10-3％. 结论 对于骨质疏松性改良Evans分型Ⅲ型股骨转子间骨折,PFNA固定较DHS固定具有明显的生物力学优势,固定强度更好,且不易导致内固定失效.     

头颈实测法在人工股骨头置换术中的应用

目的 探讨头颈实测法在人工股骨头置换术中控制肢体长度的作用.方法 回顾性分析2008年1月至2010年7月应用头颈实测法进行的人工股骨头置换术患者资料(实测组),共30例,男9例,女21例;平均年龄为71.2岁.以2003年7月至2007年10月应用经验方法治疗的60例人工股骨头置换术患者为对照组,男17例,女43例;平均年龄68.5岁.比较两组患者术后X线片测量双下肢长度差异和髋关节Harris评分结果.结果 实测组术后双下肢长短差异:优(0～5 mm)21例,良(6～ 10 mm)7例,可(11 ～ 15m m)2例,优良率为93.3％;对照组优19例,良30例,可9例,差(＞15mm)2例,优良率为82.5％,两组比较差异有统计学意义(r=8.350,P=0.008).实测组30例患者中27例术后获12 ～24个月(平均15.3个月)随访,对照组60例患者中56例术后获13～35个月(平均20.5个月)随访.末次随访时按髋关节功能Harris评分评定患髋功能:实测组优20例,良5例,可2例,优良率为91.7％;对照组优29例,良18例,可7例,差2例,优良率为83.9％,两组比较差异有统计学意义(x2=6.451,P:0.017).结论 头颈实测法在术中可以比较准确地控制人工股骨头置换后的肢体长度,是一种简便、可靠的方法.     

髋部骨折术后静脉血栓栓塞症的风险预警及多模式预防

目的:探讨采用多模式方式对髋部骨折术后静脉血栓栓塞症预防的有效性和安全性。方法:2009年3月至2011年7月,根据血栓形成危险因素将患者分为2组,低风险组112例,男47例,女65例;年龄42～88岁,平均(72.40±13.29)岁;高风险组26例,男12例,女14例;年龄65～84岁,平均(78.50±12.76)岁。2组入院后即给予间歇充气加压装置,高风险组术后第1天予低分子肝素0.4ml,皮下注射,每日1次,连续14d;低风险组术后给予口服拜阿司匹林100mg,每日1次,连续14d;在出院前24h行多普勒超声检查。术后随访3个月,分别记录下肢深静脉血栓、肺栓塞的发生率和出血并发症的发生情况。结果:所有患者未发生致命性肺栓塞,1例有症状的肺栓塞发生在低风险组,而高风险组未发现肺栓塞。低风险组术后出现深静脉血栓6例,高风险组术后出现深静脉血栓2例。选取例数较多的骨折切开复位内固定患者比较术后出血量、血红蛋白下降量、血肿及胃肠出血病例数。低风险组分别是(538.10±390.20)ml,(30±19)g/L,0例,1例;高风险组分别是(585.95±403.96)ml,(32±20)g/L,1例,1例,2组比较差异均无统计学意义。结论:阿司匹林加间歇充气加压装置在预防髋部骨折术后静脉血栓栓塞症方面的疗效与低分子肝素加间歇充气加压装置无明显差别,但在降低出血性并发症和减少心脑血管并发症方面具有潜在优势。多模式血栓栓塞预防方案可以保护患者,作为髋部骨折术后常规预防术后静脉血栓栓塞症的方法。     

Pressure-flow relationships of the canine iliac periphery and systemic hemodynamics: Effects of sodiumnitroprusside and adenosine

It has been reported that sodiumnitroprusside (SNP) decreases mean systemic pressure and simultaneously increases pressure pulse amplification towards the iliac periphery (Kenner and van Zwieten 1982). This unexpected finding was suggested to be due to a decrease in iliac peripheral resistance but an increase in iliac differential resistance. In order to investigate this apparent contradiction, the iliac periphery was hemodynamically isolated from the rest of the circulation and perfused with the dog's own blood by means of a pump. Perfusion pressure (P) and flow (F), femoral venous pressure (P_v), systemic pressure (P_s) and cardiac output (CO) were measured. Steady state pressure-flow relations of the isolated bed were obtained during control and during various i.v. infusion rates of SNP and adenosine (ADS) and were found to be straight (meanr=0.99). Their slope (P/F) was defined as differential resistance (R_d). Peripheral resistance (R_p) of the iliac bed was defined as R_p=(P-P_v)/F, calculated at the flow value where perfusion pressure equalled the prevailing systemic pressure. Total peripheral resistance (TPR) was defined as TPR=P_s/CO. The changes of R_d, R_p, P_s, CO and TPR with respect to control show that during low SNP infusion rates R_d and R_p were both increased while TPR was decreased. During all infusion rates of SNP CO did not change while P_s decreased. During low infusion rates of adenosine CO increased while P_s, R_d and R_p did not change and TPR decreased. During high infusion rates of ADS CO decreased again, R_d, R_p and P_s decreased, and TPR remained constant but at a decreased level.It is concluded that: (1) the suggestion of Kenner and van Zwieten is not supported, since SNP (as well as ADS) affects iliac peripheral and iliac differential resistance in a similar way; (2) SNP (as well as ADS) affects iliac peripheral resistance and total peripheral resistance in a differentiated way, and even in an opposite way during low infusion rates of SNP; (3) it is this opposite effect that explains the paradoxical observations of Kenner and van Zwieten; (4) for comparable reductions of TPR, CO is better maintained during infusion of SNP, while P_s is better maintained during infusion of ADS.     

The role of the splanchnic circulation in the regulation of total intravascular volume during alpha adrenergic receptor stimulation

Previous studies have not defined the contribution of the splanchnic circulation to the total intravascular volume change associated with selective alpha adrenergic receptor stimulation. Since the splanchnic circulation is responsible for the total volume changes associated with other types of selective autonomic receptor stimulation, the present study was undertaken to examine the influence of alpha adrenergic receptor stimulation on splanchnic intravascular volume, the hemodynamic mechanism responsible for the splanchnic volume change, and the contribution of the splanchnic volume change to the change in total volume. In 35 anesthetized dogs, blood from the vena cavae was drained into an extracorporeal reservoir and returned to the right atrium at a constant rate so that changes in total intravascular volume could be measured as reciprocal changes in reservoir volume. Phenylephrine infusion (100 g/min) for 20 min in 28 dogs was associated with a decrease in total volume of 64±17 (SEM) ml (P<0.0001). The response was abolished by either alpha adrenergic blockade or evisceration but was not attenuated by beta adrenergic blockade, sinoaortic baroreceptor denervation, ganglionic blockade, or splenectomy. In 5 animals with separate splanchnic perfusion and drainage, total and splanchnic volumes decreased 59±8 ml (P<0.0001) and 317±20 ml (P<0.0001), respectively, while transhepatic vascular resistance increased 17±4 cm H₂O·min/l (P<0.0001). These responses were abolished after alpha adrenergic blockade. Thus, splanchnic volume decreases with alpha adrenergic receptor stimulation, despite an increase in hepatic resistance to splanchnic, venous outflow. The splanchnic volume decrement is entirely responsible for the total volume decrement.The study was supported by NHLBI Grant 1 R23-HL27185, Grant 11-203-812 from the American Heart Association of Greater Hartford, Inc., and the Duberg Cardiovascular Research Fund. Dr. Rutlen was the Duberg Scholar in Cardiovascular Disease when the study was performed.This work was presented in part at the 1982 Scientific Sessions of the American Heart Association (Circ. 66:II-311)     

Mandibular condylectomy with osteoarthrectomy with and without transfer of the temporalis muscle

Twenty-two patients with chronic arthritis and ankylosis of the temporomandibular joint (TMJ) were treated by resection of the condyle with osteoarthrectomy and interposition with a temporalis muscle flap. We compared them with 14 patients who were treated by condylectomy and osteoarthrectomy alone. All patients were evaluated prospectively. Most patients had had a previous operation on the disc. Variables investigated before and after operation were pain during mandibular movements (using a visual analogue score (VAS) of 1–10) and impaired mandibular function such as chewing and biting off (also using a VAS of 1–10). Maximum interincisal opening was measured with a ruler. Both groups of patients showed significant improvements in all the variables evaluated. Using the predefined success criteria, both methods showed good success rates with few complications. The patients treated by interposition of the temporalis muscle tended to do better, but not significantly so. Both methods induced occlusal changes and some needed dental treatment postoperatively.