Biomechanics of the hip: forces exerted during walking

Summary Since the work of Pauwels, the forces exerted on the coxofemoral joint during walking have been studied either in different spatial planes (frontal, sagittal and horizontal) or by three-dimensional spatial analysis. Starting from the findings of our own studies, our aim was to compare the two methods of analysis (two-dimensional and three-dimensional) in order to provide a better understanding of the benefits and limitations of each method. In pursuit of this aim, we studied the pressure forces exerted on the coxofemoral joint, using a geometric plane technique following a method similar to that of Pauwels [20], and with a three-dimensional modelling technique using the finite element method. The material, taken from the published literature, was the same in both our studies. The results are expressed in terms of the size and orientation of the pressure force exerted on the coxofemoral joint during the monopodal weightbearing phase of walking. A comparison of these two methods of analysis clearly demonstrates the simplicity of two-dimensional analysis (which must incorporate as a minimum the frontal plane and the sagittal plane) and the richness of the three-dimensional analysis. The latter method, by appropriate manipulation of the information obtained, provides a starting point for computer simulations performed with the aim of testing a biomechanical or therapeutic hypothesis.

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Biomécanique de la hanche : les sollicitations à la marche

Résumé Depuis Pauwels, les sollicitations exercées sur l'articulation coxofémorale au cours de la marche ont été étudiées soit dans les différents plans de l'espace (frontal, sagittal et horizontal), soit par des analyses spatiales tridimensionnelles. A partir d'études personnelles, nous avons voulu comparer ces deux méthodes d'analyse (bidimensionnelle et tridimensionnelle) afin de dégager au mieux les apports et les limites de chacune. Pour cela, nous avons étudié les sollicitations en pression s'exerçant sur l'articulation coxofémorale, d'une part selon une étude géométrique plane dont la méthodologie s'apparente à celle de Pauwels [20], d'autre part selon une modélisation tridimensionnelle par la méthode des éléments finis. Le matériel, emprunté à la littérature, est commun à nos deux études. Les résultats intéressent l'intensité et l'orientation de la force en pression exercée sur l'articulation coxofémorale pendant la phase d'appui monopodal de la marche. La comparaison des deux types d'analyse met en valeur la simplicité de l'analyse bidimensionnelle (qui doit combiner le plan frontal et le plan sagittal au minimum) et la richesse de l'analyse tridimensionnelle qui, par la manipulation des informations obtenues, ouvre sur les simulations informatiques, en vue de tester une hypothèse biomécanique ou thérapeutique.

     

Anatomic study of the pre- and neonatal hip. Physiopathologic considerations on dysplasia and congenital dislocation of the hip

Summary Therapeutic success in dysplasia and congenital dislocation of the hip depends on an early diagnosis. The physiopathology remains very debatable and several concepts are propounded. For a better physiopathologic understanding, the authors have carried out a study of the morphology and development of 22 pre- and neonatal hips. At first, the acetabulum is cartilaginous and distorted by the moving femoral head; this acetabulum is histologicaly affected by the femoral pressure.The pathologic hip is characterized by defective posterior bony coverage of the femoral head by the acetabulum. The acetabulum ossifies during the 3 months following birth, forming a cup-like cavity under the pressure of the femoral head. Therefore, neonatal screening tests such as sonography must take place in the first weeks of life.

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Étude anatomique de la hanche antéet néonatale. Réflexions sur la physiopathologie des dysplasies et luxations congénitales de la hanche

Résumé Le succès du traitement des dysplasies et luxations congénitales de hanche est lié à la précocité du diagnostic. La physiopathologie de ces affections reste discutée et plusieurs conceptions ont pu être proposées. Les auteurs ont réalisé une étude structurale et évolutive de 22 hanches anté et néonatales afin de mieux comprendre cette physiopathologie. Dans les périodes anté- et néonatale, l'acétabulum est cartilagineux, déformable sous l'action d'une tête fémorale en mouvement et il est le siège de remainements histologiques dépendant de la pression exercée par l'épiphyse fémorale. L'ossification de l'acétabulum s'effectue lors du ler trimestre postnatal, construisant la cavité articulaire sous l'effet de la pression de la tête du fémur. Dysplasies et luxations apparaissent comme un défaut de couverture postéro-supérieure de l'épiphyse fémorale par l'acétabulum. Le dépistage d'anomalies, notamment par l'échographie, devra donc être réalisé dans les premières semaines de la vie.

     

Ⅰ期双侧全髋关节置换治疗系统性红斑狼疮合并股骨头坏死的早中期疗效

目的分析Ⅰ期双侧全髋关节置换（THA）治疗系统性红斑狼疮（SLE）合并中晚期股骨头缺血性坏死（ANFH）的早中期疗效。方法中山大学附属第三医院骨科对17例SLE合并中晚期ANFH患者均行Ⅰ期双侧THA，按照ARCO分期分为ⅢB期7髋、ⅢC期12髋，Ⅳ期15髋，结合患者年龄与骨质条件选择股骨假体不同的固定方式。采用Harris评分结合SF-36评分方法进行疗效比较与随访，平均随访时间28个月。结果术后2例切口延迟愈合，1例假体脱位，1例大腿痛10月，1例急性肾衰，均经治疗后好转。6例经彩超发现无症状下肢深静脉血栓，无肺栓塞、假体深部感染发生，无肾上腺皮质危象表现，随访期间髋关节疼痛及活动度明显改善，无假体松动。Harris髋关节功能评分（平均91．6分）与术前（平均42．6分）相比差异有统计学意义（P〈0．01），SF-36评分（平均84．5分）与术前（平均51．4分）相比差异有统计学意义（P〈0．01）；不同ARCO分期病例术后Harris评分差异无统计学意义（P〉0．05）；不同假体固定方式术后Harris髋关节功能评分、SF-36评分均差异无统计学意义（P〉0．05）。结论Ⅰ期双侧人工髋关节置换术对SLE合并中晚期ANFH的早中期疗效良好，应严格掌握手术适应证和手术时机，加强围手术期处理，选择合适的假体固定方式。     

髋关节外固定器对股骨头压力影响的三维有限元分析

目的从三维有限元分析的角度,探讨髋关节外固定器对股骨头压力的影响。方法建立正常的髋关节三维有限元模型、安装单轴髋关节外固定器(A型)髋关节三维有限元模型、安装双轴髋关节外固定器(B型)的髋关节三维有限元模型,应用接触压力分析的方法,观察并分析髋关节双足站立位、单腿站立髋关节中立位股骨头的峰值压力,并进行统计学分析。结果髋关节外固定器均能减少股骨头的接触压力(P<0．05),髋关节外固定器在双腿站立时减少最明显,B型髋关节外固定器组较A型髋关节外固定器的股骨头接触压力减小。结论髋关节外固定器可减少股骨头的压力,可辅助治疗髋关节疾病。     

The epidemiology of fragility fractures: Is there a role for bone quality?

Fragility fractures, particularly those of the hip, vertebrae, and distal forearm, constitute a major public health problem. The two ultimate determinants of fracture are bone strength and propensity to trauma. Bone strength depends not only upon bone mass but also upon a variety of qualitative aspects of bone structure. These include its architecture, the amount of fatigue damage it has sustained, and changes in its bulk material properties, indices that are collectively subsumed into the term bone quality Fragility fractures show differences in their patterns of incidence by age, sex, ethnic group, geographic area, and season. Many of these differences are currently unexplained, and disorders of bone quality might contribute to them. There are two fracture sites at which evidence implicates bone quality more directly—the spine and proximal femur. Many vertebral compression fractures follow minimal trauma, and controlled studies suggest that vertebral microarchitecture contributes to fracture risk independently of vertebral bone mass. At the hip, observational studies have pointed to a role for disordered trabecular architecture, accumulation of microfractures (fatigue damage), and the accumulation of osteoid. The extent to which these phenomena act independently of bone mass, however, remains uncertain.Presented at the NIA Workshop on Aging and Bone Quality, September 3–4, 1992, Bethesda, Maryland     

Humeruskopfresektion als therapie bei oberarmkopftrümmerfrakturen —ergebnisse

Zusammenfassung Proximale Humerusfrakturen gehö-ren zu den häufigen Verletzungen des ä1teren Menschen. Gering dislozierte Brüche können mit gutem Erfolg konservativ behandelt werden. Therapeutische Schwierigkeiten bereiten vor allem dislozierte Mehrfragment- oder Trümmerfrakturen des Oberarmkopfes. Im Zeitraum von 1970–1988 wurde in unserer Klinik in dieser Situation bei 8 Patienten eine Resektion des Humeruskopfes durchgeführt. 6 Patienten konnten bei einer mittleren Beobachtungszeit von 69 Monaten nachuntersucht werden. Alle Patienten wiesen postoperativ eine erhebliche Bewegungseinscänkung im betroffenen Schultergelenk auf. Die durchschnittliche Abduktion betrug 60° (40–80dg), die Anteflexion 60° (40–80°) bei einer mittleren AuBenrotation von 17° (5–30°) und Innenrotation von 48° (5–90°). Eine Patientin war postoperativ schmerzfrei, 2 weitere verspürten nächtliche Schmerzen, während die übrigen 3 Patienten fiber eine unterschiedliche Schmerzsymptomatik klagten. Dennoch waren 5 der 6 Patienten mit dem Operationsergebnis zufrieden, eine Patientin bewertete das Resultat mit gut.

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Resection of the humeral head in cases of head-splitting humeral fractures — results

Summary Proximal humeral fractures are frequent injuries in older patients. Most of these fractures respond satisfactorily to conservative treatment. Problems arise in cases of four-part displacements and in head-splitting fractures with massive defects in the articular surface. Between 1970 to 1988 eight patients were treated in our clinic in this situation by resection of the humeral head. 6 patients could be followed-up for an average of 69 months. Postoperative findings showed a restricted range of motion in all operated shoulders. The average abduction of the arm was 6° (40-80°) and elevation 60° (40–80°). The patients showed a mean external rotation of 17° (5–30°) and an internal rotation of 48° (5–90°). Only one patient was painless, 2 patients had pain during the night, and 3 patients suffered from various pain symptoms. Nevertheless 5 of 6 patients assessed the result as satisfactory and one patient as good.

     

先天性髋关节脱位的一期手术治疗

目的 改进先天性髋关节脱位的治疗。方法 对３８例５２髋先天性髋关节脱位术前不牵引,一期综合手术矫正全部畸形。手术步骤包括彻底软组织松解,股骨粗隆下短缩,去旋转、内翻截骨,髋臼覆盖重建,准确地同心圆中心关节复位。结果 本组５２髋术后获得满意复位,其中３０例４１髋随访８￣３０个月,按Ｍｕｌｌｅｒ和Ｓｅｄｄｏｎ的标准,优２８髋,良１０髋,可３髋。结论 一期综合手术治疗效果满意,具有住院时间短,病人痛苦小     

改进Zahradnicek手术治疗先天性髋脱位疗效观察

目的 :探讨先天性髋脱位治疗优化方法 ,减少并发症。方法 :自 1 986～ 1 998年应用改进Zahradnicek手术治疗先天性髋脱位 1 0 3例、1 36个关节 ,用特制的小儿髋臼钻有限切削臼软骨 ,重建髋臼孤形结构 ,恢复其头臼同心圆关系 ,同时矫正前倾角至 5°～ 1 0°,颈干角至1 2 0° ,用专用的 1 2 0°鹅颈钢板固定。结果 :术后疗效评定 :优 76髋 ,为 5 3% ,良 45髋 ,为 33% ,可 9髋 ,为 6 6 % ,差 6髋 ,为 4 4% ,优良率占 89%。结论 :此种手术在一次手术中使股骨头、髋臼、股骨颈及股骨干恢复或接近恢复正常解剖和功能的方法     

60岁以上患者人工股骨头置换分析

目的探讨60岁以上患者人工股骨头置换手术治疗时术前准备,手术入路及疗效.方法回顾性分析87例60岁以上患者人工股骨头置换术手术治疗的临床资料.结果①72例经髋关节前外侧入路手术,其中61例术前采用下肢皮牵引带牵引,11例术前采用骨牵引,术中复位均较容易;术后优良者占93.1%,很好者占4.2%,好者占2.7%,十年内无后脱位和修正者.②15例经髋关节后侧入路手术.其中12例术前采用骨牵引,术中复位较容易;术后优良者占80%,好者占13.3%,尚可占6.7%;术后后脱位者2例,十年内修正者2例;另3例术前采用下肢皮牵引,术中难复位2例,稍难复位1例;五年内无后脱位者,2例进行修正术.结论60岁以上患者人工股骨头置换手术采用髋关节前外侧入路较理想,术前采用下肢皮牵引带牵引即可,不需骨牵引;股骨距(即股骨颈内侧皮质)残留长度和术后早期功能锻炼是决定疗效的关键.     

THE OPERATIVE TREATMENT OF SPINAL FRACTURE-DISLOCATION WITHOUT NEUROLOGIC DEFICITS

Objective. To evaluate the results of operative treatment of spinal fracture-dislocation without neumlogic deficits. Metods. Eighteen patients with spinal fracture-dislocation were neurologically intact at the time of injury, and all were treated operatively. The fracture sites were:8 cases in cervical spine, 3 cases in thoracic spine, and 7 cases in lumbar spine. Eight patients with cervical injuries had variant degrees of forward slide and kyphotic deformity. Of the 10 thoracic and lumbar fractures, one had lateral dislocation, 4 cases with kyphotic deformities, 5 cases withspinal canal compromise averaged 50% (ranging from 40% to 70% ).Results. The aveiage period of follow-up was 4.4 years with a range of 11 months to 13 years. All the patients returned to full-time work. No patient developed neurologic deterioration. Kyphotic deformity was corrected in the 4 cases, and no progressive kyphosis was noted. There was no operation-related complication. The averaged post-opera-five hospitalization time was 13 days. Conclusions. Despite the rare incidence of spinal fracture-dislocation without neurologic deficits, we suggested that kind of fracture be considered unstable fracture because of its potential risk of delayed neurologic deterioration and kyphotic deformity, and be treated operatively to restore the sagittal alignment and the stability of the spine.