The incongruous hip joint. A casting study

A casting method for measuring the intra-articular space in the loaded hip is described. The results of tests on 22 hips from 22 cadavers show that the joint space is variable both in location and size and can disappear under light loads. It seems likely that the size and shape of the space influence how much access synovial fluid has for lubrication and nutrition.

Anatomy of the femoral neck and head, with comparative data from Caucasians and Hong Kong Chinese

The bony anatomy of the proximal femur consists of the femoral head, neck, and greater and lesser trochanters. In the adult the axis between the neck and the shaft averages 135 degrees. The femoral neck is anteverted from the transcondylar plane on the average 8 degrees in the adult. In measurements that we made of femora from cadavers of Caucasians, the anteversion angle averaged 7.0 degrees in males (range, --2 degrees to 35 degrees) and 10.0 degrees in females (range, -2 degrees to 25 degrees). Using similar techniques on cadavers of Hong Kong Chinese, we found that the average in males was 14.0 degrees (range, --4 degrees to 36 degrees) and 16.0 degrees in females (range, 7 degrees to 28 degrees). Normally the axis of the femoral head is parallel to the axis of the femoral neck, but specimens are found where there is retroversion of the femoral head. Sophisticated measurement techniques have confirmed the lack of roundness of the femoral head by establishing that the meridians have longer radii than the radii of the equator. Hence, the femoral head has a subtle egg or barrel shape. There are significant differences in the measurements of the head, neck, and proximal femoral shaft of average normal Caucasian and Hong Kong Chinese people.

Biomechanics of the human hip

The hip joint is one of the body's most amenable joints to a lowering of its interarticular pressure by surgery. It has been shown that such a lowering of pressure can predictably have a significant amelioratory effect on osteoarthrotic degeneration. A workable understanding of the biomechanics of the hip is essential in the planning of any meaningful orthopedic intervention to attempt to delay or reverse hip joint degeneration.

Dislocation in total hip arthroplasties

In a series of 1,443 total hip arthroplasties performed between 1970 and 1975, dislocation was the most frequent complication and its incidence was found to be increasing. Dislocatin was frequently associated with component malposition that the surgeon was not aware of at the time of surgery and was relatively frequent among less experienced surgeons. It was especially frequent if the patient had had previous hip surgery and was related to the difficulty of the surgery rather than the primary hip disease. Increasing incidence was associated with change in operative technique and less stringent patient selection. Dislocation was 2 1/2 times more frequent if trochanteric osteotomy was not performed. The tip of the greater trochanter was moved significantly closer to the center of the prosthetic head in the patients who dislocated. Traction for up to three weeks did not lower the incidence of subsequent dislocation compared with mobilization of the patients as soon as tolerated after dislocation. Surgery was effective in preventing further dislocations in patients with recurrent dislocation and component malposition. The use of an articulated prosthesis is not recommended.

The diagnosis of congenital hip-joint dislocation by the ultrasonic Combound treatment

Due to poor penetration of bone, ultrasonic techniques have not been popular in orthropedic procedures. Since they are non-invasive and are not associated with a radiation hazard, their application in the diagnosis of congenital hip-joint dislocations merits investigation. Methods are presented in Part I which should enable the experienced investigator to make the diagnosis and avoid flash interpretations. In Part II, the practical results of these techniques over an 18 month period are presented and discussed. The small size of the object under examination and the, in general, poor resolving power of ultrasonoscopes constitute the major difficulties encountered when using ultrasonic diagnostic devices. The fact that these methods are harmless to the patient, economical, simple to perform, and noninvasive, make them attractive diagnostic tools for screening infant hip-joints congenital luxations.

[Age and changes in the fascial compartment structures in the coxofemoral joint region]

Investigations performed on 66 corpses beginning from 5-month-old embryos up to 75 years of age by methods of anatomical preparations (sections were studied after N. L. Pirogov) and on total histotopographical preparations revealed anteromedial, anterolateral and posteroinferior fascial nodes in the area of the coxofemoral joint. The anteromedial node is formed by the network that consists of connective tissue fibres of fascial cases covering the lumboinguinal and pectinate muscles and the common sheaths for the artery and vein. The anterolateral node is formed by the network that consists of the connective tissue fibres of the rectal muscle case, the sheaths of the lateral vessels circumflexing the femur and fasciae of the musculus sartorius and m. tensor fasciae femoris. The posteroinferior node is formed by the network that consists of the connective tissue fibres of the fascial cases of the m. obturatorius, internal and external, fascial sheaths of the internal pudendal vessels and the ischiadic nerve. The fascial nodes in question morphologically complete their formation by the end of the fetal period. In young and adolescent age their components have abundant fibroblastic cells, collagenous and elastic fibres are correctly oriented. By 20 years of development, the fascial nodes are dense and their supporting-protective role is clearly evident. After 55 years of age, the fascial nodes are subjected to involutional alterations characterized by decreasing number of cells, rough collagenous fibre fasciculi, transformed elastic fibres. All these signs demonstrate that their protective and supporting functions decrease at this age.

Arthrosonography--technique, sonographic anatomy, and pathology

Ultrasound scanning of the hips, shoulders, and elbows was investigated as a noninvasive technique for the diagnosis of joint disorders. Sixteen patients with known intra-articular fluid collections, loose bodies, or periarticular abnormalities were studied. Ultrasound images clearly demonstrated the contours of bony surfaces, normal muscles, and other soft-tissue structures around joints. Intra-articular fluid collections were seen as sonolucent halos around the femoral neck and humeral head and as an oval, sonolucent area anterior to the distal humerus. Collections of fluid as small as 10 ml in the hip and 16 ml in the shoulder were visualized. Intra-articular loose bodies and para-articular fluid collections were also demonstrated. It is concluded that gray-scale ultrasound can demonstrate some of the basic pathologic processes in joint disorders. Further evaluation of its scope and applicability is indicated.

The biomechanics of the pediatric hip

Containment refers to the relationship of the most lateral part of the femoral epiphysis to the lip of the acetabulum. Congruence refers to the relation between articular surfaces, but is not as useful a concept as sphericity. Coverage refers to the relationship of the lateral lip of the acetabulum to the resultant force across the hip joint and in most cases is best estimated by the center-edge angle. Femoral heads can be well contained but poorly covered and vice versa. Appreciation of these three concepts is important, not only in considering treatment of the pediatric hip but also in communicating with one's colleagues. Varus osteotomy redirects muscle forces about the hip and improves containment. The innominate osteotomy has these effects also but in addition improves coverage.

[Valgus osteotomy in treatment of osteoarthrosis of hip (author's transl)]

The article reports on Bombelli's theory on the genesis of arthrosis of the hip. Clinical experience has shown that valgus and extension osteotomy is indicated in dysplasia arthrosis, in cystic changes and formation of osteophytes. Although the good clinical results cannot be accepted as a proof of the biomechanical deliberations, they do extend the range of indications pointing to surgery of the diseased hip joint performed for the purpose of preserving the femoral head.

The African neonatal hip and its immunity from congenital dislocation

The hips of twenty full-term African neonates have been examined in detail to determine any anatomical factors which might explain the difference in the incidence of congenital dislocation of the hip in the African and in the Caucasian. Measurements included the degree of anteversion of the femoral neck and the acetabulum and the diameter and depth of the acetabulum. The acetabulum tended to be deeper and to vary within a much narrower range than that reported for Caucasians, lending indirect support to the theoretical role of acetabular dysplasia in the aetiology of congenital dislocation of the hip. Measurements of the anteversion of the acetabulum and femoral neck were similar to those given for Caucasians.

Direct anchorage of Al2O3-ceramic hip components: three years of clinical experience and results of further animal studies

The biocompatibility of high-purity dense Al2O3-ceramics had been shown to open the possibility of direct cement-free anchorage of joint endoprostheses. Three years of clinical experience with ceramic-metal composite total hip prostheses confirm the biomechanical design criteria used for the acetabular components. They also allow for additional conclusions regarding the reaction of bone tissue towards a bioinert implant. Further research activities are directed towards a solution for biomechanically stable anchorage of the femoral component of hip prostheses.

[A method for the measurement of the collodiaphyseal angle in case of external rotational contracture (author's transl)]

The authors discuss the objectivity of measurements for the collodiaphyseal angle of the hip fixed in external rotation on the a.p. projection. Since the antetorsion cannot be measured because of the external rotation contracture, an alternative projection is proposed. Several pictures are demonstrated for the determination of the rotation. To find the true value of the distorted collodiaphyseal angle the authors propose a formula for the calculation on theoretical grounds. They consider this formula valuable for clinical use.

The thickness of the cartilage in the hip joint

The pattern of distribution of cartilage thickness in corresponding femoral heads and acetabula was ascertained in ten hip joints. The differences between individual acetabula and their corresponding heads were small enough for it to be admissible to calculate an average distribution pattern for head and socket. Comparison of these patterns showed that: (a) The maximum thickness is found at points in the ventrocranial area of the acetabulum and ventrolateral area of the head. (b) From these points the cartilage thickness decreases concentrically. (c) In the 'natural position' of the hip joint the points of maximum thickness of head and acetabular cartilage do not correspond. In relation to the line of the hip joint 'force resultant', the area with the thickest cartilage on the head is slightly shifted towards its medial side, and on the socket slightly to the lateral side. It is not possible fully to explain these results on the basis of existing conceptions about the functional stressing of the hip joint.

The joint space in normal hip radiographs

The hip joint space in standard anteroposterior images of 120 normal subjects was measured with the aid of a special transparent pattern. The normal value was slightly over 4mm, scattered between 3 and 5 mm, except for elderly men in whom values of 6 mm or more may be normal. The lower borderline value does not change with age, nor is there any change in the average joint space with age except in men in whom it increases slightly. A narrow joint space in an elderly patient should not be expected simply because the patient is old. The measuring technique is useful in population studies. In individual cases a simple measurement with a ruler serves the same purpose if the outline of the acetabular roof is well-defined on the images.

[Köhler's "tear drop". Relationship between the radiologic picture and anatomic substrate]

The diagnostic value and anatomical basis of Köhler's "tear drop" has been in doubt. By means of radiographs of the right side of the pelvis taken with various degrees of rotation tilt, and by X-raying serial sections, it was possible to demonstrate how this appearance is produced. It was shown which parts of the pelvis contribute to the "tear drop". This simplifies an understanding of the radiographic appearances of the pelvis in the region of the hip joint.

Sexual dimorphism and mechanics of the human hip: a multivariate assessment

The present research was undertaken to determine the effects of sexual dimorphism in the human pelvis and femur on the mechanics of human locomotion. The analysis was based on six biomechanical variables determined from 25 male and 32 female skeletal remains from the Dickson Mound site. Discriminant function analysis indicates that the mechanical variables which primarily contribute to dimorphism are the moment arm of the gluteus medius and the torque produced by the abductors at the hip. These mechanical aspects of hip function produce greater pressure on the femoral head in females.

The CE angle of normal hips

The Center-Edge angle (CE angle) of Wiberg was measured in normal hips in patients between 8 and 75 years of age. Males and females were recorded separately. Means and standard deviations are presented here. The angle increased with growth up to adult age, and then only slowly. In children only values below 15 degrees can be classified as abnormal.

An experimental study of hip stability in human newborn cadavers

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[Results of treatment with Pavlik harness for congenital dislocation of the hip (author's transl)]

The results of treatment with Pavlik harness in 168 hip joints have been reviewed. The average follow-up period was 8 years 6 months. In total 114 hip joints were treated only by Pavlik harness. Four hip joints were treated by surgical methods after conservative treatment. The results were very good in 81.0%. Subluxated hips were in 8.9%. Coxa valga et antetorta in 6.0% and deformed head in 4.1%. In a high percentage of our cases radiologically very good results were found. Joint development must be further followed up.

[The development of the dysplastic hip-joint following intertrochanteric rotating varus-osteotomy (author's transl)]

Evaluation of radiographs of 267 children with 465 intertrochanteric rotating varus osteotomies, carried out between the ages of 15 months and 14 1/2 years. The period of follow-up varied between 2 and 15 1/4 years. 1. The CCD angle on the last radiograph was normal in 77%, once more in values in 16.2%, coxa vara in 7%. 2. The AT angle was about normal only in 58.3% (0-20 degrees); it relapsed in 8.4% (over 35 degrees); in 8.8% a corrected angle did not return after retrorotation, particularly on the left. 3. The Ac angle was normal in 63.3%. 4. The CE angle corresponded to the norm in 59.1%. 5. Good late results (normal angles and shape of head) occur only in 20%. If one omits the AT condition, they rise to 40%. 6. The main causes of return of valgus appear to be: too early operation before the fifth year, mainly when disregarding the dysplastic acetabular roof, insufficient correction of the CCD angle of over 115 degrees, and technical faults. For physiologic weightbearing by the acetabular roof an AT angle of 10 appears necessary. 7. When dysplasia of the acetabular roof is present, the polyaxial correction of the proximal end of femur must be combined with acetabuloplasty or pelvic osteotomy.

[Results of the Chiari pelvic osteotomy (author's transl)]

This is a report about 82 Chiari pelvic osteotomies, the functional and the x-ray results are demonstrated. On the x-rays of the hip the CE- und the ACM-angles were measured routinely. In opposite to satisfying results on the x-rays we did not find adequate functional results.

Walking patterns of men with unilateral surgical hip fusion

The gait of men with unilateral hip fusion is somewhat slow, asymmetrical, and arrhythmic as compared with that of normal men. Compensation for absent hip motion is accomplished by increased transverse and sagittal rotation of the pelvis, increased motion in the sound hip, and increased flexion of the knee throughout the stance phase on the fused side. Relationships between the fusion position, certain physical traits, and walking performance suggest that the best gait can be expected in young patients who have free motion of the lumbar spine, the sound hip, and the knee on the side of fusion, and who have equal limb lengths and a hip fused in a position that does not include excessive adduction.

The hip joint: structure, stability, and stress; a review

A review of the structure of the hip joint as related to its stability is presented. The forces exerted at the hip and along the proximal end of the femur are discussed in relation to the anatomical position of bone and to normal stresses incurred during standing and gait. Clinical considerations of selected hip abnormalities include a review of changes in normal mechanical forces found in coxa valga, coxa vava, arthritis, and fracture.

[The Salter innominate osteotomy as the treatment of congenital dislocation and subluxation (author's transl)]

The Salter innominate osteotomy is useful in the treatment of congenital dislocation and subluxation of the hip after the age of 18 months. The procedure provides stable reduction of the femur even with weight bearing. In addition, the acetabulum depth is not diminished and the head is covered with hyaline cartilage. Derotation-varization intertrochanteric osteotomy improves hip biomechanics and when done in combination with the innominate osteotomy, the wedge of bone from the femur may be used in the ilium, precluding the necessity for a separate iliac graft. Combined Salter innominate osteotomy, intertrochanteric femoral osteotomy and open reduction as a single operation has produced satisfactory results and has distinct advantages over staged procedures.

[Biomechanics of the hip joint. I. A new model for the calculation of the forces in the hip joint]

After a short review of the theory of the forces acting in the human hip joint we develope a new model for the calculation of the forces R acting on the head of the supporting femur, of their direction phi and of the maximal pressure of the femoral head. The new concept is the determination of a fixed point A, the attachement of the resultant muscle force M at the pelvis, and the insertion T of this muscle force at the trochanter. After determination of this points in a single standard radiography of the pelvis and hips, the model calculate the resultant force R at the hip joint. The pressure in the articulation is calculated also by the same proceeding. The influence of the choice of the point A is discussed.

Anatomic restoration of congenital hip dysplasia in adulthood by total hip displacement

Congenital dysplasia, treated or untreated, produces a hip joint difficult to reconstruct and is even more difficult when coxarthrosis supervenes producing significant disability. Total hip replacement can be dramatically successful in these patients, and equals those with coxarthrosis without congenital dislocation. The acetabulum must be totally reconstructed and relocated as near as possible to its original orientation. Usually a small straight stem femoral component must be placed into a generally constricted femoral canal. A thoughtful preoperative plan including X-ray templates is absolutely essential for a successful reconstruction without postoperative complications.