肘关节内侧副韧带断裂对肱桡关节影响的生物力学研究

目的测量肘关节内侧副韧带(MCL)前束完整及断裂时在不同屈曲状态下肱桡关节的生物力学指标,探讨肘关节MCL前束对肱桡关节的生物力学影响。方法取人体肘关节标本,按是否切断肘关节MCL前束将标本分为对照组(MCL前束保留完整)及试验组(MCL前束被切断),分别测量2组标本在不同屈曲角度下(0°、30°、60°、90°)肱桡关节内平均压强和肱桡关节的接触面积。结果肘关节屈曲30°、60°时,试验组肱桡关节内平均压强大于对照组,肱桡关节接触面积小于对照组,差异有统计学意义(P0.05);而肘关节屈曲0°、90°时,2组肱桡关节内平均压强、肱桡关节接触面积差异无统计学意义(P0.05)。结论肘关节MCL前束在肘关节稳定中意义重大,其断裂后可导致肘关节内侧不稳定,造成肱桡关节内压强增大、关节接触面积减小。     

肘关节内侧副韧带前束重建后肱桡关节的生物力学变化

目的通过比较肱桡关节在肘关节内侧副韧带(medial collateral-ligament,MCL)前束完整组与重建组的生物力学数据,评价通过界面螺钉固定人工肌腱重建MCL前束的疗效。方法本次实验选取人类肘关节作为标本,首先将标本分为对照组(前束完整组)及实验组(前束重建组),每组各20例,然后将压敏胶片(pressure sensitive film,PSF)放到肱桡关节内,当肘关节内侧副韧带前束处于不同屈曲角度(0°、30°、60°、90°)和不同状态(完整及重建)时分别测量肘关节外翻松弛度、肱骨小头与桡骨小头的接触面积及肱桡关节内的压强,数据应用SPSS 19.0统计软件进行分析。结果肘关节处于0°、30°、60°、90°时,肘关节外翻松弛度组内及组间比较差异无统计学意义(P0.05)。肘关节处于0°时,对照组和实验组的肱桡关节内压强均明显小于肘关节处于屈曲30°、60°、90°时关节内的压强(P0.05);肘关节处于30°、60°、90°时组内及组间肱桡关节内压强比较差异无统计学意义(P0.05)。前束完整组中,肘关节处于0°位时肱桡关节的受力面积最大(P0.05),两组其余各角度组内及组间比较差异均无统计学意义(P0.05)。结论在维持肘关节外翻稳定性方面,肘关节内侧副韧带前束的作用十分关键,使用人工肌腱重建肘关节内侧副韧带前束可以使肘关节内侧结构迅速恢复至正常状态,不但可以降低肱桡关节内压强,还可以增加肱桡关节接触面积,最终达到降低肱桡关节慢性损伤的发病率。     

肘关节内侧副韧带前束重建的生物力学研究

目的通过测量肘关节内侧副韧带(medial collateral ligament,MCL)前束生物力学指标,探讨前束完整及重建后对肘关节外翻稳定性的影响,评价采用人工肌腱、界面螺钉重建MCL前束疗效。方法成人完整上肢标本12具,男8具,女4具;左、右侧各6具;制成肘关节"骨-韧带"标本。采用生物力学及压敏胶片测量方法,分别测量MCL前束完整(对照组)及使用人工肌腱、界面螺钉重建后(实验组)肘关节屈曲0、30、60、90°时关节外翻松弛度、肱尺关节受力面积及肘关节内压强。结果两组在肘关节不同屈曲角度下,组内及组间关节松弛度比较,差异均无统计学意义(P>0.05)。除肘关节屈曲0°时两组肘关节压强小于其余屈曲角度(P<0.05),及对照组小于实验组(P<0.05)外,两组其余各角度组内及组间比较差异均无统计学意义(P>0.05)。除对照组内肘关节屈曲0°时肱尺关节受力面积大于其余屈曲角度(P<0.05)外,两组其余各角度组内及组间比较差异均无统计学意义(P>0.05)。结论 MCL前束对维持肘关节外翻稳定性具有重要意义,金属界面螺钉加人工肌腱重建后可即刻恢复内侧稳定。     

肘关节内侧副韧带前束的生物力学研究

尺侧副韧带(MCL)复合体为关节囊的增厚部分,由前束、后束及斜束构成.前束是肘关节内侧稳定的主要结构,临床上MCL损伤时应重点修复或重建MCL前束以稳定肘关节[1].我们采用压敏胶片对肘关节进行应力及受力面积的分析. 一、材料与方法 防腐保存的正常成人尸体的完整上肢标本12例,其中左、右各6例;男8例,女4例.采用长春试验机研究所生产生物力学试验机(CSS-44020型)及FUJIF-ILM超低压双片型压敏胶片在肘关节不同屈曲角度下承受150 N垂直压力及1.5 N/m外翻扭矩下的外翻松弛度[2].     

胫骨远端内外翻畸形对胫距关节接触的影响

目的通过生物力学方法研究胫骨远端不同程度内外翻畸形对胫距关节接触情况的影响,以及腓骨截骨在其中的作用。方法选取8具新鲜下肢标本,通过踝上截骨建立胫骨远端内外翻模型,包括9种工况:正常中立位(A组),保留腓骨的10°内翻模型(B组)、5°内翻模型(C组)、5°外翻模型(D组)、10°外翻模型(E组),及截断腓骨后的10°内翻模型(F组)、5°内翻模型(G组)、5°外翻模型(H组)、10°外翻模型(I组)。通过Tek Scan踝关节压敏片法测试不同工况下胫距关节的接触面积、接触压强及峰值压强,观察胫距关节受力中心的位置变化。结果 B~E组接触面积、接触压强及峰值压强与A组比较差异均无统计学意义(P0.05)。截断腓骨时,F、I组接触面积显著小于A组(P0.05),F、H、I组接触压强及F、I组峰值压强均显著大于A组(P0.05)。胫距关节在正常中立位载荷时,有前外侧和前内侧两个主要受力区域;关节整体的受力中心位于前外侧象限,接近关节中心区域。保留腓骨时,随着内翻角度的增大,受力中心向前外侧转移;随着外翻角度的增大,受力中心则向后内侧转移。截断腓骨时,受力中心的移位正好相反,内翻时向后内侧转移,外翻时则向前外侧转移。结论腓骨的完整性对胫骨远端内外翻畸形的胫距关节接触情况有显著影响;临床中针对不同的畸形特征,应选择合适的截骨方式。     

重建肘关节外翻稳定性的生物力学研究

目的　评价肘关节桡骨头 (radial head,RH)切除、尺侧副韧带 (medial collateral ligament,MCL )损伤以及 RH假体置换、MCL重建后的外翻稳定性。　方法　新鲜成人尸体上肢标本 12侧 ,制成肘关节“骨 -韧带”标本 ,在2 N· m的外翻力矩作用下 ,分别在肘关节 0°、30°、6 0°、90°和 12 0°伸屈时 ,测量肘关节外翻松弛度 :1完整肘关节(n=12 ) ;2 MCL切断 (n=6 ) ;3RH切除 (n=6 ) ;4 MCL切断 +RH切除 (n=12 ) ;5 RH假体置换 (n=6 ) ;6 MCL重建(n=6 ) ;7RH假体置换 +MCL重建 (n=12 )。用 SPSS 10 .0统计软件包作方差分析 ,比较各组的外翻稳定性。　结果　完整肘关节的平均外翻松弛度最小 ;RH切除后 ,外翻松弛度增大 ;单纯 MCL切断 ,外翻松弛度大于单纯 RH切除 (P<0 .0 1) ;MCL切断 +RH切除 ,外翻稳定性最差 ;行 RH假体置换 ,对稳定性有改善 ;MCL重建与完整 MCL差异无统计学意义 (P>0 .0 5 ) ;RH假体置换同时重建 MCL ,效果最好。　结论　 MCL是抵抗肘关节外翻应力最主要的因素 ,RH是次要因素。在重建肘关节的外翻稳定性方面 ,MCL的重建比 RH的假体置换更重要。在无条件行 RH假体置换时 ,修复MCL是较好的手术方式。     

单束重建与解剖双束重建治疗内侧副韧带Ⅲ级损伤的生物力学比较研究

目的比较单束重建与解剖双束重建治疗膝关节内侧副韧带(medial collateral ligament,MCL)Ⅲ级损伤后膝关节稳定性差异,为临床MCL损伤治疗提供生物力学参考。方法取自愿捐赠的成人新鲜膝关节标本9具,随机分为3组(n=3)。其中,正常MCL组仅行前交叉韧带(anterior cruciate ligament,ACL)离断并单束重建,保留完整MCL。单束重建组及双束重建组均离断ACL、MCL浅层(superficial MCL,sMCL)及后斜韧带(posterior oblique ligament,POL),制备MCLⅢ级损伤模型;ACL单束重建后,分别行sMCL单束重建、sMCL及POL解剖双束重建。采用生物材料动态力学试验机测量各组膝关节完全伸直位及屈曲不同角度时,胫骨前方移位距离(anterior tibial translation,ATT)、胫骨内旋角(internal rotation,IR)、胫骨外翻角(valgus rotation,VAL),以及内旋及外翻力矩作用下MCL及ACL受力情况。结果膝关节完全伸直位及屈曲15°、30°、45°、60°、90°位时,3组ATT差异均无统计学意义(P0.05)。单束重建组膝关节完全伸直位及屈曲15°位时IR及VAL,以及屈曲30°位时VAL,均明显大于双束重建组及正常MCL组(P0.05);双束重建组与正常MCL组差异均无统计学意义(P0.05)。膝关节完全伸直位及屈曲15°、30°位时,内旋、外翻力矩作用下,3组MCL及ACL受力差异均无统计学意义(P0.05)。结论相比单束重建,解剖双束重建治疗MCLⅢ级损伤可以更好地恢复膝关节的外翻及旋转稳定性。     

桡骨头骨折合并肘内侧副韧带前束损伤的临床解剖和功能研究

[目的]解剖学观察肘内侧副韧带前束(anterior bundle of medial collateral ligament,AMCL)损伤发生的部位、性质;探讨桡骨头骨折合并AMCL损伤对肘关节功能的影响及一期手术修复韧带疗效评价。[方法]2008年1月~2012年10月收治的桡骨头骨折合并AMCL损伤患者44例,男23例,女21例;年龄20~70岁,平均43.8岁,均为急性闭合性损伤,按照Mason分型Ⅱ型15例、Ⅲ型15例、Ⅳ型14例。按照分层随机分配方法分为对照组24例(AMCL损伤保守治疗);观察组20例(AMCL损伤手术治疗)。对照组开放复位内固定桡骨头骨折后单纯行屈肘90°石膏托外固定3周;观察组一期手术行骨折开放复位内固定+修复AMCL损伤,术后屈肘90°石膏托外固定制动3周。对两组患者治疗前行肘关节外翻应力X线片及MRI检查,并评估治疗前后HSS评分、提携角、关节间隙及肘关节各屈曲角度下偏离角度水平。[结果]全部病例获得随访,随访时间12~26个月,平均20.4个月。本研究中韧带损伤手术修复组20例患者,AMCL自内上髁止点撕脱15例(75%)、体部断裂4例(20%)、冠突止点断裂1例(5%),其中AMCL自内上髁止点撕脱和体部断裂者占95%。两组患者治疗前肘关节外翻应力X线片内侧关节间隙、提携角比较、MRI冠状位SE序列T2加权像高信号率比较,差异均无统计学意义;两组患者末次随访肘关节外翻应力X线片内侧关节间隙、提携角、肘关节各屈曲角度下偏离角度水平比较,差异有统计学意义;两组患者治疗前肘关节HSS评分比较,差异无统计学意义,末次随访HSS评分比较,差异有统计学意义。[结论](1)桡骨头骨折合并AMCL断裂部位多在肱骨内上髁附着处和体部,多为撕脱伤,可直接修复;(2)桡骨头骨折合并AMCL损伤可明显影响肘关节功能及稳定性。(3)AMCL损伤一期手术修复后可有效改善肘关节功能及稳定性。     

肘关节创伤中内侧副韧带重建必要性之辩

肘关节创伤中内侧副韧带结构损伤较为常见。内侧副韧带复合体分为前、斜、后三束,前束起始于肱骨内侧髁的前下部,止于尺骨冠突的前内缘。斜束紧贴尺骨面,连续前束和后束在尺骨上的止点。后束起于肱骨内侧髁的内下缘,止于尺骨鹰嘴近中1/3内缘。2009年肘关节恐怖三联征治疗指南中治疗肘关节恐怖三联征应常规行外侧副韧带修复,是否需要修复内侧结构（包括内侧副韧带及共同屈肌复合体）是争论焦点。肘关节恐怖三联征损伤不一定都损伤外侧副韧带,也有可能仅损伤内侧副韧带。内侧副韧带前束在抗外翻应力方面起主要作用,是肘关节内侧稳定的主要结构。内侧副韧带前束是肘关节韧带中最坚韧的一束,从肘关节伸直到屈曲60°的过程中呈紧张状态;屈曲超过60°,在抗外翻应力方面前、后束共同起作用。Eygendaal等通过长期随访发现,大部分内侧副韧带损伤的患者都存在肘关节外翻不稳定相关性疾病,如关节退化、异位骨化、疼痛等,因此认为应该对存在内侧副韧带损伤的患者进行MCL修复。Jeong等对13例肘关节恐怖三联征患者在对修复肘关节外侧的同时,常规通过外侧入路或内侧入路修复内侧受损结构,平均随访25个月,Mayo评分为平均95分（85~100分）,获优10例,良3例。他们认为采用内、外侧入路修复所有内、外侧损伤组织可达到满意的临床及影像学效果,建议对于肘关节恐怖三联征患者应常规修复关节内侧结构。Toros等认为一般仅对外侧结构修复完毕后仍存在持续性肘关节屈伸不稳定或明显外翻不稳定的患者,应采取内侧入路修复内侧结构。     

肘关节尺侧副韧带的生物力学评价

肘关节尺侧副韧带由前束和后束组成[1-4],其前束被认为是肘关节抗外翻应力的主要结构[4-7],前束损伤将导致肘关节轻度的外翻不稳定及在做投掷动作时肘内侧疼痛.前束又可分为前部和后部[3,4,8].肘关节尺侧副韧带各组成部分在维持肘关节稳定中的生物力学作用目前尚不明确.本实验通过系统的解剖学和生物力学研究,探讨肘关节尺侧副韧带各组成部分在肘关节运动时的生物力学作用,研究肘关节外翻不稳定的发生机制.     

Stabilizers of capitellocondylar total elbow arthroplasty

The contribution of the medial and lateral collateral ligaments (MCL, LCL) and muscle forces to the kinematics and stability of the capitellocondylar total elbow arthroplasty was investigated in six fresh cadaveric elbows. The three-dimensional orientation of the ulna relative to the humerus was monitored with the use of an electromagnetic tracking device in neutral, valgus, and varus stress positions with (1) the ligaments intact, (2) LCL insufficiency obtained by osteotomizing the lateral epicondyle, (3) partial MCL insufficiency obtained by sectioning either the anterior or posterior bundle of the MCL, and (4) complete MCL insufficiency. Simulated muscle forces were applied as follows: (1) no load, (2) 1 kg each to the biceps and the brachialis and 2 kg to the triceps, and (3) 2 kg to the biceps and the brachialis and 4 kg to the triceps. The laxity was defined as the difference in valgus/varus orientation of the ulna in the valgus and varus stress positions. The laxity at 40°, 75°, and 110° elbow flexion was analyzed. The greatest laxity occurred with LCL insufficiency (40.7° ± 11.6°, average at three flexion angles) followed by that with MCL insufficiency (15.7° ± 9.9°), both of which were significantly larger than laxity with the intact ligaments (5.6° ± 2.5°). The laxity with the anterior bundle sectioned (12.0° ± 8.1°) was significantly greater than with the posterior bundle sectioned (3.3° ± 3.6°); thus the contribution of anterior bundle to stability was four times that of posterior bundle. Stabilizing effect of muscle loading was small in elbows with intact ligaments, whereas it was large with LCL or MCL insufficiency. Based on these data, we can see that the integrity of both the MCL and LCL is essential to maintain stability of this total elbow, the anterior bundle is a more important stabilizer than the posterior bundle, and the collateral ligaments seem to be the primary stabilizer and the musculature seems to be the secondary stabilizer. Careful implantation technique to preserve the collateral ligaments is required to obtain postoperative stability of this arthroplasty. Otherwise, routine exposure of the MCL and repair or reinforcement of the MCL, if deficient, may need to be considered during surgery.     

尺骨鹰嘴骨折不同程度骨量丢失对肘关节稳定性的影响

目的 探讨尺骨鹰嘴骨折时不同程度骨量丢失对肘关节稳定性的影响.方法 取10具20侧男性新鲜上技标本,在距尺骨鹰嘴尖部10 mm处向远端截骨,制备鹰嘴中部不同程度骨缺损,即骨量丢失模型,截骨分为4组,每组5侧上肢标本,即尺骨鹰嘴完整组、截除3mm组、截除6mm组、截除9 mm组,骨折断端予张力带内固定后,测量每组肘关节屈伸活动范围变化及肘关节在屈曲30°、60°、90°、120°时,前臂施加1.96 N·m扭距,肘关节内外翻角度的变化,同时观察肱尺关节关系.结果当尺骨鹰嘴截骨至3 mm时,肘关节的伸直活动开始受限;当尺骨鹰嘴截骨至6 mm时,CB片示肱尺关节出现不服贴,鹰嘴尖紧贴滑车关节面,滑车与鹰嘴之间间隙增大,肘关节的伸直活动明显受限;当尺骨鹰嘴截骨至9mm时,CR片示肘关节明显处于半脱位,滑车切迹的弧度基本消失.肘关节屈曲30°、60°、90°时,随截骨量增大肘外翻角度增大,当截骨量达到6 mm时外翻角度明显增大,差异有统计学意义(P＜0.05).而肘关节屈曲30°、60°、90°、120°时,内翻角度组间差异无统计学意义(P＞0.05).结论 尺骨鹰嘴中部截骨缩短达到6mm时,滑车切迹弧度发生改变,出现肘关节不稳定.临床对于尺骨鹰嘴中部粉碎性骨折如短缩不超过6 mm可单纯固定,否则应考虑原位植骨内固定.     

An anatomic investigation of the elbow joint, with special reference to aging of the articular cartilage

The architecture of the articular surface of the elbow joint and the location of cartilage degeneration with aging was analyzed. The study included 131 elbow joints of 66 cadavers preserved by embalming. The age of subjects at death ranged from 49 to 96 years (mean 79 years). The elbow joint was observed macroscopically and analyzed. The degenerative changes in the radiohumeral joint were always more advanced than those in the humeroulnar joint. The erosion or chondral defect in the capitulum is located in the area 45° anterior to the long axis of the humerus. The anterior part of the erosion in the crest separating the trochlea from the capitulum was roughly 48.5° to the long axis of the humerus. It was similar in position to the erosion found in the capitulum. Based on the degree and area of cartilage degeneration, the changes in the radial head could be divided into four types. The mode of radial head cartilage degeneration correlated well with cartilage degeneration in the radiohumeral articulation and also with osteoarthritis of the elbow joint. Simplistically, one could classify elbow joint osteoarthritis by knowing the extent of radial head degeneration.     

Kinematics of partial and total ruptures of the medial collateral ligament of the elbow

In this study the kinematics of partial and total ruptures of the medial collateral ligament of the elbow are investigated. After selective transection of the medial collateral ligament of 8 osteoligamentous intact elbow preparations was performed, 3-dimensional measurements of angular displacement, increase in medial joint opening, and translation of the radial head were examined during application of relevant stress. Increase in joint opening was significant only after complete transection of the anterior part of the medial collateral ligament was performed. The joint opening was detected during valgus and internal rotatory stress only. After partial transection of the anterior bundle of the medial collateral ligament was performed, there was an elbow laxity to valgus and internal rotatory force, which became significant after transection of 100% of the anterior bundle of the medial collateral ligament and was maximum between 70 degrees to 90 degrees of flexion. No radial head movement was seen after partial or total transection of the anterior bundle of the medial collateral ligament was performed. In conclusion, this study indicates that valgus or internal rotatory elbow instability should be evaluated at 70 degrees to 90 degrees of flexion. Detection of partial ruptures in the anterior bundle of the medial collateral ligament based on medial joint opening and increased valgus movement is impossible.     

Single-strand ligament reconstruction of the medial collateral ligament restores valgus elbow stability

The purpose of this study was to determine the contribution of the central portion of the anterior bundle of the medial collateral ligament (MCL) to elbow stability and to evaluate the effectiveness of a single-strand MCL reconstruction in restoring elbow stability. Testing of 11 fresh-frozen upper extremities was first performed on the intact elbow and then with the capsule, flexor-pronator muscle group, posterior bundle, anterior or posterior band, and central band cut sequentially. Next, a single-strand reconstruction of the MCL was performed. The elbow was moved passively through a full arc of flexion in both varus and valgus gravity-loaded positions. Ulnar movement with respect to the humerus was analyzed by means of an electromagnetic tracking system. Maximum varus-valgus laxity throughout the arc of supinated flexion and pronated flexion was 6.6 degree plus minus 2.4 degree and 7.4 degree plus minus 2.0 degree, respectively, for the intact specimen, 34.2 degree plus minus 5.6 degree and 37.7 degree plus minus 11.8 degree for the specimen with all of the medial valgus elbow stabilizers cut, and 9.0 degree plus minus 2.5 degree and 10.5 degree plus minus 2.7 degree for the reconstructed specimen. Maximum varus-valgus laxity was not significantly different among any of the sectioning sequences until the central band was cut (P <.0001). There was no significant difference in maximum varus-valgus laxity between the intact and reconstructed elbows (P <.05). Our results demonstrate that the central band is an important valgus stabilizer of the elbow and that a simplified single-strand reconstruction is able to restore stability to the MCL-deficient elbow.     

A biomechanical study of stability of the elbow to valgus stress before and after reconstruction of the medial collateral ligament

The purpose of this study was to assess the stability of the elbow to valgus loads after reconstruction of the anterior bundle of the medial collateral ligament (MCL). The MCL in 14 human cadaveric elbows was exposed with a muscle-splitting approach. Each sample was secured in a materials test frame,5 N-m valgus moments were applied in 30 degrees, 60 degrees, 90 degrees, and 120 degrees of flexion, and baseline stability was measured. This sequence was performed after the anterior bundle was sectioned and again after ligamentous reconstruction was done with the Jobe technique. At 30 degrees, 60 degrees, 90 degrees, and 120 degrees of flexion, reconstruction reproduced an average of 99%, 102%, 97%, and 89%, respectively, of the stability of the intact ligament. The only significant difference between intact and reconstructed samples was at 120 degrees of flexion (P <.05). We concluded that this procedure reliably restores stability to a ruptured MCL throughout the flexion arc in the immediate postoperative period.     

尺骨鹰嘴部分切除对肘关节稳定性影响的研究

目的探讨尺骨鹰嘴尖部截骨短缩对肘关节稳定性的影响。方法取10具20侧男性新鲜上肢标本，随机分为四组，每组5侧标本，即尺骨鹰嘴完整组、截骨3mm组、截骨6mm组、截骨9mm组，截骨在尺骨鹰嘴尖部。每组分别在肘关节屈曲30°、60°、90°、120°时，前臂加1．96Nm力矩的情况下，测量外翻位肘外翻角度和内侧副韧带前束长度及内翻位肘内翻角度和桡侧尺副韧带长度。结果尺骨鹰嘴尖部截骨时，于同一肘关节屈曲位，随着尺骨鹰嘴尖部截骨量增大，肘关节内侧副韧带前束的长度逐渐变长，外翻角逐渐增大，当截骨量大于3mm上述变化差异显著，有统计学意义（P〈0．05）。结论尺骨鹰嘴尖部截骨量超过3mm时，肘关节出现不稳定。因此临床上当尺骨鹰嘴尖部严重粉碎性骨折片不超过3mm时，可予以手术切除，对肘关节稳定性影响不大，否则应给予修复重建。而对于尺骨鹰嘴尖部后内侧骨赘，建议仅切除骨赘或切除范围不超过正常鹰嘴尖部3mm。     

Fractures of the olecranon: an in vitro study of elbow joint stresses after tension-band wire fixation versus proximal fracture fragment excision

BACKGROUND: Displaced fractures of the olecranon usually require operative treatment, by either open reduction with internal fixation (ORIF) or excision of the proximal fragment. However, the relative merits of these treatment options have not been fully delineated. One treatment outcome measure of joint function is residual intra-articular stress. The purpose of this study was to evaluate the effect of these two types of olecranon fracture treatment on humeroulnar joint stress. METHODS: Eight matched pairs of fresh frozen cadaveric upper extremities were thawed; stripped of skin, muscular, and neurovascular tissue; and potted in polymethylmethacrylate. The intra-articular humeroulnar joint peak pressures were measured at 90 degrees of elbow flexion using pressure-sensitive film after application of a 0.15 kg-m torque through the remaining triceps muscle attachment. First, pretreatment (normal) pressures were obtained from the major contact regions of the humeroulnar joint. A 50% olecranon osteotomy was then performed simulating a fracture, and the elbows from each of the paired specimens were randomly assigned to one or the other of two treatment groups: ORIF (using a tension-band wiring technique) and proximal fragment excision. Joint pressures were remeasured. A two-tailed paired t test was used for statistical analysis. RESULTS: After osteotomy, the peak pressures were higher, overall, in the excision group. Comparing each posttreatment experimental group to its pretreatment (normal) counterpart revealed that the peak pressures in the distal medial and distal lateral articular subzones were significantly higher for the fragment excision group (p = 0.005 and p= 0.0008, respectively), but were not significantly different in the ORIF group (p = 0.545 and p= 0.153, respectively). CONCLUSION: The findings of this study indicate that ORIF restores the normal biomechanics of the elbow joint and proximal fragment excision results in abnormally elevated joint stresses. These elevated joint stresses may, over time, contribute to the development of elbow pain and osteoarthrosis. Therefore, ORIF should continue to be regarded as the treatment of choice for displaced fractures of the olecranon involving large proximal fracture fragments similar in size to those in this study.     

Anatomy of the anterior bundle of the ulnar collateral ligament

The purpose of this project was to study the anatomy of the anterior bundle of the ulnar collateral ligament and provide anatomic measurements not previously described. Thirteen fresh-frozen cadaver elbows were dissected. A 3-dimensional, electromagnetic, digitizing device was used to measure several anatomic parameters of the anterior bundle of the ulnar collateral ligament. The width of the ligament was not uniform, increasing distally toward the insertion. The average area of the origin was 45.5 mm2, and the average area of the insertion was 127.8 mm2. The edge of the insertion was separated from the ulna articular margin by an average of 2.8 mm. The study provides quantitative data describing the anatomy of the anterior bundle of the ulnar collateral ligament. This information may prove useful in surgical techniques designed to reproduce the anatomy and biomechanics of the elbow after injury.