Osteochondroma and secondary synovial osteochondromatosis

Secondary synovial osteochondromatosis (SOC) is a rare disorder caused by a variety of joint disorders. Two unusual cases of secondary SOC are presented. The first patient is a 43-year-old man with extensive SOC developing within a bursa surrounding an osteochondroma of the pubic bone. The second patient is a 23-year-old man who developed florid and progressive SOC of his hip joint following excision of a femoral neck osteochondroma. SOC recurred despite three excisions over a 15-month period. Imaging was useful in pre-operative diagnosis of bursal SOC in the first patient and in detecting multiple recurrences in the second patient. Both cases illustrate prominent SOC developing secondary to osteochondroma. The different hypotheses regarding bursal and secondary SOC are reviewed. Received: 8 October 1998 Revision requested: 28 October 1998 Revision received: 13 November 1998 Accepted: 16 November 1998     

Transient osteoporosis of the Hip: a densitometric study

Summary Three new cases of transient osteoporosis of the hip are reported. Diagnosis was achieved by plain radiographs, bone scintiscan, magnetic resonance imaging and X-ray absorptiometry of proximal femurs. The densitometry showed at the Ward's triangle a mean reduction of bone mineral density in the affected side of 36%. All subjects were treated with i.v. clodronate for ten consecutive days with a complete recovery of femoral density within 4 months. X-ray absorptiometry allows a quantification of the demineralization process and can be useful in the long term evaluation of this entity.     

Four and a half years experience with a vertical flow sterile enclosure

Summary During the use of a vertical flow enclosure of our own design for almost five years, bacteriological studies and the infection rates in different groups of patients have taught us the following:1. In a clean room operating theatre, the use of a respired air exhaust system improves the sterility compared with the use of ordinary masks. In a vertical flow enclosure, the chest, the arms, and the hands of the team are contaminated from respired airborne bacteria if helmets, etc., are not worn.2. In our vertical flow enclosure with almost continuous absolute sterility of the air, the infection rate in primary total hip replacement is very low and less than 1%, including early and late infections. Antibiotics have not been used.In secondary surgery, i.e., total hip replacement in hip joints previously operated upon, the infection rate is markedly higher, probably because of a flare-up of latent infection.Clean room surgery therefore, can only prevent air borne contamination, and no more; but this is very valuable.3. Vertical flow enclosures of the Charnley-Howorth (1975) and Weber et al. (1971) type provide considerable improvement in sterility of the air compared with adaptations of more conventional theatres. We recommend that these facilities be made available for implant surgery. It is also necessary to have a stringent operational policy with cooperation and discipline on the part of all members of the theatre team.

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Résumé Durant l'utilisation, depuis plus de 5 ans, de la serre stérile à flux laminaire vertical que nous avons construite, nous avons pratiqué des études bactériologiques et pu comparer les taux d'infection suivant les groupes de patients.1. Dans une salle d'opération propre, la stérilité est considérablement améliorée par le port de casques possédant un système d'aspiration de l'air expiré, ceci par rapport au port de masques ordinaires. De plus, si l'on ne porte pas le casque dans une serre à flux laminaire vertical, le tronc, les mains et les membres supérieurs de l'équipe chirurgicale sont contaminés par les microbes en suspension dans l'air expiré.2. Dans notre serre où l'air est pratiquement stérile, le taux d'infections précoces et tardives est inférieur à 1% dans les arthroplasties de la hanche, et cela sans utilisation d'antibiotiques.Lors d'interventions dites secondaires, c'est-à-dire dans les cas déjà opérés au préalable, par exemple par ostéotomie, ostéosynthèse, etc., le taux d'infection est plus élevé. On doit probablement en rechercher la cause dans une contamination de la plaie lors de la première intervention, l'infection alors à l'état latent pouvant se réveiller à la faveur d'une nouvelle opération.En opérant dans une serre stérile, on peut donc prévenir la contamination par l'air ambiant, mais pas plus. Cela est cependant déjà très appréciable.3. Comparées aux salles d'opération conventionnelles modernes, les serres stériles à flux laminaire vertical, comme celle de Charnley-Howorth (1975) et Weber-Meierhans (1971), améliorent considérablement la stérilité de l'air. Surtout pour la chirurgie prothétique de la hanche, dont les risques d'infection sont élevés, nous recommandons l'emploi de ce genre d'installation. Mais il est nécessaire que tous les membres de l'équipe chirurgicale adoptent des règles très strictes de discipline.

     

Forces and moments on the human leg in the frontal plane during static bipedal stance.

An experimental apparatus was assembled that permitted measurement of the vertical and lateral ground reaction forces as the hip is abducted, resulting in foot separations ranging from 0.25 to 71 cm, with the knee in 0 degree flexion. Twelve healthy volunteers (8 men and 4 women) were tested. The hip joint was located by means of center of rotation measurements on each subject's legs, and the location of the knee joint was determined using anatomical measurements. It was observed that the mediolateral force was nonzero and directed toward the body midline, even when the subject's feet were placed together. With the feet placed at shoulder width, the population mean mediolateral force was 3% of body weight. It was determined that simplifying assumptions based upon either "zero lateral force," or "zero hip moment," produced errors, when compared with our measured values, over various ranges of foot separation, with the zero hip moment assumption providing accuracy over a broader range. The inclination of the tibial plateau, with respect to the long axis of the tibia, that would produce minimal mediolateral shear at the knee is presented. Research and clinical applications of our results and techniques are discussed.     

药物对微粒刺激单核细胞溶骨性因子分泌的影响

目的建立人工关节无菌性松动的体外模型，探讨药物防治人工关节松动的可能性。方法(1)体外模型：人体外周血单核细胞分别与骨水泥、聚乙烯和钛合金微粒混合培养，测定上清中溶骨性因子。(2)实验分组：采集志愿献血外周血，分离单核细胞。分骨水泥、聚乙烯和钛合金三组。每组再分4亚组，I亚组：单核细胞；H亚组：单核细胞十微粒；Ⅲ亚组：单核细胞十微粒十帕米膦酸钠；IV亚组：单核细胞十微粒十降钙素。培养48小时，检测上清TNF-α、IL-l和IL-6的含量。结果Ⅱ亚组上清中溶骨因子含量高于I、Ⅲ、IV(p＜0．01)；I、Ⅲ、IV组间差异无统计学意义(P＞0．05)。结论二磷酸盐类药物和降钙素能够抑制微粒对单核巨噬细胞的激活作用，并能直接抑制破骨细胞，因此有望成为防治人工关节无菌性松动的有效药物。     

髋臼造顶术治疗159例先天性髋关节脱位回顾性分析

目的：评价先天性髋关节脱位髋臼造顶术的疗效。方法：为１５９例（２０４髋）先天性髋关节脱位的患儿进行了髋关节切开复位、股骨上端短缩截骨、髋臼造顶术。患儿年龄１．５￣１３岁，平均７．５岁。结果：随访３年５０例（６６髋），随访１０年以上２９例（３７髋）。按Ｍｃｋａｙ临床评定标准，３年随访组优良率为８７．８％，随访１０年组为８５．０％。按Ｓｅｖｅｒｉｎ的Ｘ线评定标准，随访３年及１０年组均为７３．０％。结论     

强直性脊柱炎髋关节软组织的扫描电镜和X线能谱观察及其临床意义

目的：采用扫描电镜—Ｘ线能谱联机观察强直性脊柱炎（ＡＳ）髋关节囊和滑膜组织的病理变化，用以指导临床治疗。方法：对６例年青ＡＳ病人的髋关节囊和滑膜组织进行固定、干燥、喷金行扫描电镜观察，并用２例老年股骨头坏死髋关节炎的同名组织作对照。对扫描图象中的组织进行Ｘ线能谱扫描以确定是否存在钙颗粒。结果：ＡＳ组的关节囊和滑膜组织中胶原排列紊乱，其间有钙颗粒沉积。而对照组同名组织仅见胶原排列紊乱，Ｘ线能谱显示无钙峰出现。结论：青年ＡＳ病人髋关节囊和滑膜组织均有成骨现象发生，而老年股骨头坏死髋关节炎同名组织无成骨现象。这种软组织病理变化是影响ＡＳ髋关节功能的主要原因。其关节清理术需将关节囊和滑膜全部切除。     

Do the hamstrings and adductors contribute to excessive internal rotation of the hip in persons with cerebral palsy?

Children with cerebral palsy frequently walk with excessive internal rotation of the hip. Spastic medial hamstrings or adductors are presumed to contribute to the excessive internal rotation in some patients; however, the capacity of these muscles to produce internal rotation during walking in individuals with cerebral palsy has not been adequately investigated. The purpose of this study was to determine the hip rotation moment arms of the medial hamstrings and adductors in persons who walk with a crouched, internally-rotated gait. Highly accurate computer models of three subjects with cerebral palsy were created from magnetic resonance images. These subject-specific models were used in conjunction with joint kinematics obtained from gait analysis to calculate the rotational moment arms of the muscles at body positions corresponding to each subject’s internally-rotated gait. Analysis of the models revealed that the medial hamstrings, adductor brevis, and gracilis had negligible or external rotation moment arms throughout the gait cycle in all three subjects. The adductor longus had an internal rotation moment arm in two of the subjects, but the moment arm was small (<4 mm) in each case. These findings indicate that neither the medial hamstrings nor the adductor brevis, adductor longus, or gracilis are likely to be important contributors to excessive internal rotation of the hip. This suggests that these muscles should not be lengthened to treat excessive internal rotation of the hip and that other factors are more likely to cause internally-rotated gait in these patients.     

Acetabular ossicles: normal variant or disease entity?

Ossicles located in the acetabular fossa may confuse diagnostic and therapeutic work-up. An accessory ossification centre may persist unfused as an os acetabuli centrale which is surrounded by intact hyaline cartilage representing an anatomic variant. Bone islands located in the pillars of the acetabulum can project into the acetabular fossa simulating acetabular ossicles. Osteochondrosis dissecans, posttraumatic articular bodies, degenerative disease and other rare lesions may be responsible for clinical symptoms and are of similar appearance than anatomic variants. Plain film radiography, X-ray tomography, CT and MRI are used to categorize these lesions. MRI is very valuable to assess cartilage integrity in a noninvasive way, but arthro-CT or arthro-MRI have to be used in unclear cases. Therefore the purpose of this presentation is to discuss the appearance, the possible etiology and the differential diagnosis of acetabular ossicles and how they can be evaluated to avoid an unnecessary arthrotomy. Received: 22 December 1998; Revised: 28 May 1999; Accepted: 8 July 1999     

MR arthrography of the hip: normal intra-articular structures and common disorders

This pictorial review illustrates the anatomical features of normal intra-articular components of the hip and their common disorders on MR arthrography. On T1-weighted MR arthrograms, the normal contrast-filled joint cavity shows a homogeneous high signal intensity. Normal acetabular labrum appears as a well-delineated triangle showing a low signal intensity, surrounded by contrast material in the perilabral recess. Intra-articular paramagnetic contrast outlines labral tears, loose bodies, communicating labral cysts and cartilage lesions (traumatic tears, focal defects, degenerative fissures and thinning), and improves their detection. Overall, MR arthrography enables accurate detection and staging of hip intra-articular structure abnormalities. Received: 6 June 1998; Revision received: 2 January 1999; Accepted: 2 April 1999