R. A. B. Mollan

Graduated compression stockings: knee length or thigh length.

The mechanisms by which graduated compression stockings prevent deep venous thrombosis are not completely understood. In the current study the physiologic effect of low-pressure graduated compression stockings on the venous blood flow in the lower limb and the practical aspects of their use were assessed. Patients having elective orthopaedic surgery at a university orthopaedic department were randomized into five groups to wear two different types of graduated compression stockings in thigh and knee lengths. Patients in the fifth control group did not wear graduated compression stockings. Venous occlusion strain gauge plethysmography was used to measure venous flow. After 20-minutes bed rest there was a highly significant increase in venous capacitance and venous outflow in patients in all of the four groups wearing stockings. There was no difference in the mean of the percentage change of venous capacitance in patients in the four groups wearing stockings. The knee length Brevet stockings were less efficient in increasing the venous outflow. There was no significant change in the venous capacitance and venous outflow in patients in the control group. Visual assessment of the fit and use of stockings was done, and patients’ subjective opinion of comfort was sought. The knee length graduated compression stockings wrinkled significantly less, and significantly fewer patients reported discomfort with them. All stockings were reported to be difficult to use. Thigh and knee length stockings have a significant effect on decreasing venous stasis of the lower limb. Knee length graduated compression stockings are similarly efficient in decreasing venous stasis, but they are more comfortable to wear, and they wrinkle less.

Familial Expansile Osteolysis

Familial expansile osteolysis (FEO) is a unique bone dysplasia, which has, over five generations, affected 42 members of a Northern Ireland family. The disease follows a classic autosomal dominant pattern of inheritance. The condition is distinct enough in its clinical features and natural history to be recognized as a new and unique disease. There are both general and focal skeletal changes, the latter having a predominantly peripheral distribution and an onset from the second decade. Progressive osteoclastic resorption accompanied by medullary expansion leads to severe and painful disabling deformities with a tendency to pathologic fracture. Most affected members of the family have an associated early-onset deafness and loss of dentition as a result of unique middle ear and dental abnormalities. The serum alkaline phosphatase and urinary hydroxyproline are elevated to a variable degree, whereas other biochemical indices are normal. The response of the disease to a therapeutic trial using parenteral dichloro-methylene-diphosphonate (dichloro-MDP) produced an initial rapid biochemical response, which was not sustained.

The Effect of Active Movement of the Foot on Venous Blood Flow after Total Hip Replacement

Surgeons often encourage patients to move their feet in an attempt to prevent venous stasis, but there is little evidence that this measure is beneficial. We investigated the effect of active movement of one foot on the venous blood flow four days after total hip replacement. The actual venous outflow at rest was measured with use of venous occlusion strain-gauge plethysmography in thirty-eight patients. The patients were randomly allocated to the control group (eighteen patients) or the exercise group (twenty patients). A baseline measurement was followed by a one-minute period of rest (control group) or of maximum plantar flexion and dorsiflexion of the foot, ankle, and toes at a rate of thirty cycles per minute (exercise group). The venous outflow was measured again at two, seven, twelve, and thirty minutes in both groups. Movement of the foot for one minute produced a significant and sustained increase (p < 0.002) in the venous outflow (mean maximum increase, 22 per cent). The value remained greater than the baseline level for thirty minutes (mean increase, 6.5 per cent) (p < 0.2). The increase was gradual, reaching a maximum twelve minutes after the completion of exercise. Our results confirm the beneficial hemodynamic effects of active movement of the foot in the postoperative period and suggest that patients should move the feet and ankles postoperatively as part of a prophylactic regimen directed at decreasing the risk of venous thrombosis.

The diagnostic potential of vibration arthrography.

The detection and interpretation of vibration emission from the locomotor system is a sensitive, noninvasive method for the objective study of human joints. The projects reviewed here aimed to identify and categorize vibration signals from various joints, chiefly the neonatal hip and the adult knee. Using a vibration detection and computerized analysis system, various studies have suggested that vibration arthrography will be a potentially valuable diagnostic service for the orthopedic surgeon of the 1990s.

Total hip replacement, lower limb blood flow and venous thrombogenesis

The effect of Charnley cemented total hip replacement on venous blood flow in the legs and its relationship to deep-vein thrombosis were investigated in 413 patients. Blood flow was measured using strain-gauge plethysmography before operation, after surgery, and after discharge from hospital. There was a significant reduction in both venous capacitance and venous outflow, affecting both legs but greater in the operated leg. Venous flow remained significantly below preoperative levels in the operated leg six weeks after surgery. There was a highly significant correlation between the degree of reduction in blood flow and the development of postoperative deep-vein thrombosis. Venous stasis was shown to be a major factor in venous thrombogenesis.

A Critical Appraisal of Auscultation of Human Joints

Auscultation of human joints is a rarely practiced art. Many attempts have been made to develop a technique with objective parameters but none are sufficiently sensitive for clinical use. This article reviews the history of auscultation as applied to human joints. An acoustic system was critically evaluated and attempts were made to exclude skin friction and ambient noise. Human joint sounds were found to be at the low end of the acoustic range. The microphone was a poor transducer in terms of frequency and dynamic sensitivities for use with human joint emission because of the large acoustic impedance. Many of the problems encountered by workers in this field might be due to failure to appreciate the limitation of detection apparatus.

Dislocation of total hip replacements. A comparative study of standard, long posterior wall and augmented acetabular components.

Augmentation of the acetabular component of total hip replacements is a method of increasing stability and preventing recurrent dislocation. We report a series of mechanical experiments designed to evaluate the turning moments and angles required to dislocate standard, long posterior wall and two different augmented prostheses.

A Study of the Cracking Sounds from the Metacarpophalangeal Joint

The familiar cracking sounds produced by distraction of the metacarpophalangeal joints were studied using accelerometers and a computerized signal analysis system. The joints were distracted in a controlled manner using a motorized device which simultaneously monitored the load on the joint and its extension. The load and extension parameters and those from the signal analysis were used to examine diurnal variation, the effects of multiple distractions, distraction speed, hand temperature and loading between distractions, and to show that in many cases, the energy contained in a crack signal, expressed as a ratio of the articular cartilage volume, exceeded a known level needed to produce articular cartilage damage.

VENOUS HAEMODYNAMICS IN BOTH LEGS AFTER TOTAL KNEE REPLACEMENT

We studied the effect of total knee replacement on venous flow in 110 patients. Resting venous blood flow was measured using strain-gauge plethysmography before operation, after surgery and after discharge from hospital. There was a significant reduction in mean venous capacitance (p < 0.001) and mean venous outflow (p < 0.004) affecting only the operated leg. Both improved significantly after mobilisation in the early postoperative period, returning to preoperative levels by six days after surgery and before discharge from hospital. Our findings showed that venous stasis may contribute to deep-vein thrombosis only in the first few days after total knee replacement. This would be the most important period for the use of flow-enhancing prophylactic devices. Comparison with changes in blood flow after total hip replacement identified different patterns of altered haemodynamics suggesting that there are different mechanisms of venous stasis and thrombogenesis in hip and knee arthritis and during surgery for these conditions.

Culture of human osteoblasts on demineralised human bone. Possible means of graft enhancement

We cultured human osteoblasts from trabecular bone explants and confirmed their phenotype by alkaline phosphatase assay, increased cyclic adenosine monophosphate production in response to prostaglandin E2 and radiographic micro-analysis of nodules of calcification. The osteoblasts were seeded on to demineralised human bone fragments and examined at ten-day intervals over a 50-day period by scanning electron microscopy. During this time the bank bone became progressively repopulated by the cultured osteoblasts. This system may offer a means of graft enhancement in elective orthopaedic and maxillofacial surgery by delivery of cultured autologous human osteoblasts to bone defects.