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Trendelenburg's test of function of the hip joint was first reported before radiology was available. At least four methods of performing it have since been described in the literature. We examined 50 normal subjects and 103 people with disorders affecting either the spine or the hip, in order to determine the different responses that occurred when they were asked to stand on one leg. This has enabled us to define a standard method of performing the Trendelenburg test, and to interpret the test as a method of assessing hip abductor function. The major pitfalls that result in misinterpretation, or false-positive responses, are pain, lack of cooperation from the patient, and impingement between the rib cage and the iliac crest. False-negative responses result from the patient using muscles above and below the pelvis, and from leaning beyond the hip on the standing side.

This paper examines the fate of decalcified allografts (homografts) of iliac cancellous bone impregnated with autologous red marrow and implanted intermuscularly into the anterior abdominal wall of rabbits. In contrast to the findings of Urist and other workers that cortical bone decalcified with hydrochloric acid (HCl) and then freeze-dried is inductive to new bone formation in various heterotopic sites, evidence is presented that iliac bone decalcified by HCl and grafted alone to a muscular site is itself very weakly inductive to bone formation. However, when combined with autologous bone marrow the HCl-decalcified bone provides a better substrate for bone formation by marrow cells than does either undecalcified iliac bone, or iliac bone decalcified with ethylene-diamine-tetra-acetic acid. The freezing or freeze-drying of decalcified bone does not affect new bone formation when implanted alone or with autologous marrow. The differences between the cortical and cancellous bone as inductive substrates for osteogenesis are discussed and the interrelationship of bone and marrow in combined bone grafts are re-evaluated.

1. The normal activity of the medial articular nerve of the knee joint of nine dogs was measured in response to continuous passive movement. Whole nerve recordings were made simultaneously with joint position and angular velocity. 2. When the knee was moved the medial articular nerve discharged at all joint angles with maximum activity at flexion in some animals, and at extension in others. For an individual animal the discharge pattern was reproducible over several cycles of movement. 3. The discharge was direction sensitive, responding with a lesser activity whenever the joint was moved away from the extremes of movement range. 4. With higher velocities of movement, the discharge activity of the nerve increased at the ends of joint movement. 5. The results indicate that the discharge activity of the whole medial articular nerve is influenced not only by joint position but also by the velocity and acceleration of movement. This may reflect changes in the tension of capsular and extra‐capsular tissues.

Intra‐articular pressure levels were determined for joint positions throughout the normal physiological range of movement of dogs' knee joints. Change in joint position resulted in change in intra‐articular pressure. It was demonstrated that intra‐articular pressure is highest with the joint in the fully flexed position. Minimum pressure was recorded at a position between 80 degrees and 120 degrees. Minimum pressures were usually subatmospheric. The rate of change of joint position affected intra‐articular pressure. The relationship of intra‐articular pressure and joint position before and after full flexion demonstrated a hysteresis effect; the pressures were lower than for the same joint position before flexion. Maintenance of the joint in the fully flexed position for increasing periods of time between repeated movement cycles resulted in a similar reduction, of constant magnitude, in pressure between joint positions before and after each period of flexion. However, there was also a progressive decrease in pressure for all joint angles over the total number of movement cycles. There is a contribution to intra‐articular pressure of joint capsular compliance and fluid movement into and out of the joint (both of which are time‐dependent). The recording of intra‐articular pressure in conscious, upright dogs revealed similar pressure levels to those measured in anaesthetized supine dogs. The major determinants of intra‐articular pressure in normal dog knee joints include joint size, synovial fluid volume, position of joint, peri‐articular tissue and joint anatomy, membrane permeability, capsular compliance, and movement of fluid into and out of the joint.

This study has investigated changes in intra‐articular hydrostatic pressure in the knee joints of normal dogs in response to continuous and stepwise infusions of fluids. The relationship between pressure and volume in the joint was examined over the pressure range of ‐8 to +50 mmHg, and also at much higher pressures often associated with joint disease or injury. The effects of joint angle and dog weight on the pressure‐volume relationship and on elastance of the dogs' knees were also examined. With liquid paraffin B.P. the pressure was found to increase more with each unit volume infused at subatmospheric pressures than at pressures around atmospheric, and increased more again at higher pressures. The pressure‐volume curve with saline infusions was affected by egress of fluid from the joint at supra‐atmospheric pressure. Above +5 mmHg the rise in pressure per unit volume infused was less than that for paraffin at the same volume. Elastance and compliance of the normal joint capsule were calculated from the pressure‐volume data. Elastance was high at subatmospheric pressures, decreased rapidly as atmospheric pressure was approached and rose as a linear function of pressure above 12 mmHg. The biphasic shape of the elastance‐pressure curve is discussed, and explanations for the shape are suggested. After intra‐articular pressure in the knee was raised by infusion of paraffin oil the joint was moved through the range of positions from 125 deg extension to 50 deg flexion. Intra‐articular pressure did not change across the range 125‐110 deg. However, increasing the angle of flexion from 110 to 50 deg resulted in a rise in pressure which became steeper for each volume increment. Increasing intra‐articular fluid volume caused a decrease in the total range of movement of the joint. The pressure‐volume curves measured at extended angles of 110, 125 and 140 deg, where the starting pressures were subatmospheric, were the same. At flexed joint positions of 80 and 50 deg, where the starting pressures were supra‐atmospheric, the pressure‐volume curves became steeper with greater flexion. Elastance of the joint tissues increased with flexion. The elastance at each joint angle depended also on the volume or pressure. Significant differences were found to exist between pressure‐volume curves for three groups of animals of different weight.(ABSTRACT TRUNCATED AT 400 WORDS)

The acute childhood diseases haematogenous staphylococcal osteomyelitis and septic arthritis were studied concurrently using avian models which closely resemble the human diseases. Ultrastructural studies during the initial stages of bone and joint infection showed that adherence of bacteria to cartilage, bacterial proliferation, cartilage destruction and subsequent bacterial spread along the vascular channels within cartilage were common to both disease processes. Histological studies revealed that transphyseal blood vessels were present in the growing chickens and were a likely explanation for the frequency of the concurrence of acute osteomyelitis and adjacent joint infection following intravenous injection of bacteria. Transphyseal vessels provide a direct connection between the growth plate (physis) and epiphyseal cartilage supplying a route for bacteria to spread from an osteomyelitic focus in the metaphysis to the epiphysis and subsequently to the joint lumen.

Single‐ and multi‐unit recordings were obtained from the medial articular nerve (m.a.n.) of knee joints in the anaesthetized dog. The single‐unit recordings were confined to low threshold (group I and II) articular mechanoreceptors. Multi‐unit recordings revealed that the m.a.n. discharge was maximal in extension, submaximal in flexion, and minimal at intermediate angles, i.e. a U‐shaped profile. Subatmospheric intra‐articular pressures do not appear to influence the m.a.n. discharge. Intra‐articular infusion of even small quantities of fluid, although not affecting the U‐shaped profile, reversed the m.a.n. discharge pattern with maximum neural activity occurring in flexion and being submaximal in extension. Recordings from single units indicated that the enhanced discharge after fluid infusion was a result of increased discharge frequency and 'recruitment' of individual afferents.

A model of acute hematogenous osteomyelitis initiated by injection of Staphylococcus aureus into 29-day-old chickens was used. Transmission electron microscopy showed that the bacteria adhered to exposed cartilage matrix in the metaphyseal region of long bones but not to adjacent vascular linings or to erythrocytes. It is proposed that the combination of exposure of growth plate cartilage during normal bone growth and the ability of S. aureus to adhere to this cartilage is the mechanism for initiation of infection which proceeds to an osteomyelitic abscess.

Three unusual injuries of the cervical spine in wearers of safety belts are reported. In each case, the presence of diagonal bruising and abrasions in the line of the sash strap indicated its involvement in the mechanism of the injury.

Background: There are numerous studies about morbidity and mortality, technical complications and in-hospital factors after proximal femoral fracture surgery in the elderly. Although experienced clinicians are often able to make an accurate prediction, little information is available about the factors that allow early determination of whether a patient may return to the community. The present study aimed to provide that information and, hence, allow better use of health resources.
Methods: At Westmead Hospital a prospective study was conducted of 304 patients with a proximal femoral fracture who were previously residing at home. A number of different factors were analysed using statistical methods to determine their effect on outcome, which was defined simply in terms of whether the patient was able to return to the community or whether they needed institutional care.
Results: Factors that had an adverse influence on return to the community were: a low activities of daily living (ADL) score on admission; increasing age; dementia; the use of regional analgesia; and the occurrence of postoperative complications. Other factors such as gender, fracture type, delay to surgery and length of stay were not significant.
Conclusions: Consideration of the ADL score, age and mental state at the time of admission to hospital is all that is needed to determine return to the community. This is helpful to the patient and their family, and allows an early and appropriate referral pattern to either community services or a nursing home.