The design and testing of a composite lower limb prosthesis.

In unilateral lower limb prosthetic gait, the intact limb, together with the hip on the affected side, strive to compensate for the loss of the missing below-knee musculature. The resultant abnormal gait patterns can eventually lead to pathologies of the spine and other joints. The aim of this research was to design a trans-tibial dynamic elastic response (DER) prosthesis which could simulate the power generation and absorption properties of an intact foot and shank segments. A carbon fibre sickle-shaped prosthesis was developed in which the strain energy from the early part of the stride was stored, and was released again at the point of take-off, to simulate the action of the missing musculature. Stress analysis techniques were used in the design of the prosthesis, for the purposes of computing and maximizing the strain energy of the elements. A force transducer was designed into the prosthesis to verify the analysis. Video motion analyses of the prosthesis were carried out in order to determine the most appropriate shape that would reduce gait asymmetries. The research shows that biomechanical techniques, together with good engineering design and the selection of modern materials, can lead to a prosthesis which approaches the function of a natural foot.

Forces generated in guide-wires when drilling human bone.

In orthopaedic surgery guide-wires are extensively used for the drilling of pilot holes in human bones to allow further drilling, reaming and screw-tapping to take place in the repair and reconstruction of fractures. The guide-wires are generally 1.5 to 2.5 mm in diameter and have a three-faceted point with or without a screw thread. This paper describes drilling tests carried out using both types of guide-wire and these are compared with results obtained from a two-faceted geometry developed during this research. Tests were performed on the heads of femurs which had been removed during hip arthroplasty. A variable speed drilling machine together with a very sensitive drilling dynamometer were used for measuring the torque and thrust during the experimental stage of the research. This equipment was developed as part of an overall research programme into the mechanics of drilling of human bone. The indications are, firstly, that little advantage is gained by using a threaded-point guide-wire. In fact using a thread on the guide-wire can be a disadvantage. Secondly, the thrust cutting force is dependent on the spindle speed and feed. An optimum set of speeds of between 800 and 1400 r/min is recommended for 2.5 mm diameter guide-wires.

Acyclovir ointment plus topical betamethasone or placebo in first episode disciform keratitis.

Thirty patients with first episode disciform keratitis and with no previous steroid exposure were randomly assigned to double blind treatment with 3% acyclovir ointment and 0.1% betamethasone (Betnesol) drops or acyclovir ointment and matching placebo. In the steroid group 14 of the 15 patients healed in a mean time of 21.8 days. In the placebo group eight of the 13 patients healed in a mean time of 34.5 days. The difference in mean healing time between the two groups was significant (p < 0.05). The cumulative rate of healing was also quicker in the steroid group when compared with the placebo group (p < 0.001). Other clinical parameters improved more favourably in the combination treatment group. Four patients, two in either group, experienced a mild transient punctate epitheliopathy, but no other serious adverse effects were noted. There has been no significant difference in the recurrence rate between the two groups after a mean follow-up period of approximately 3 years.

Randomised double-masked trial of lodoxamide and sodium cromoglycate in allergic eye disease. A multicentre study.

135 patients were entered into a 28-day randomized double-masked multicentre study comparing the efficacy and short-term safety of lodoxamide 0.1% ophthalmic solution (Alomide--Alcon Laboratories), a mast cell stabilizer, with sodium cromoglycate 2% ophthalmic solution (Opticrom--Fisons Pharmaceuticals) in the treatment of allergic eye disease. Patients given lodoxamide 0.1% showed a significantly more rapid and greater improvement in their signs and symptoms of allergic eye disease than patients given sodium cromoglycate 2%. Both treatments were found to be safe, and side-effect profiles were comparable between the two treatment groups, although the overall incidence of side-effects in this study was found to be less frequent in the lodoxamide-treated group.

Twice daily 4% Sodium Cromoglycate vs. 2% Sodium Cromoglycate used four times daily in seasonal (grass pollen) allergic conjunctivitis.

It is well established that 2% Sodium Cromoglycate is an effective treatment for a number of allergic eye diseases. It has been shown to be non-toxic. It can be used longterm and in serious allergic problems it is a useful adjunctive therapy to steroids. The main problem with Sodium Cromoglycate is that the recommended dosage is a four times daily application and patient non-compliance is common. One of the main objectives of any therapy is to reduce the frequency of dosage and the current study has been designed to investigate the efficacy of a 4% solution of Sodium Cromoglycate, used twice daily, versus a 2% solution used four times daily in seasonal allergic conjunctivitis. A multicentre study, therefore, was carried out to assess the efficacy of both drugs and to assess any possibility of side effects. In addition, a unit dose was used, thus eliminating preservatives and it was used specifically in seasonal allergic conjunctivitis in the pollen season. This study showed that 4% Sodium Cromoglycate used twice daily was at least as affective as 2% Sodium Cromoglycate used four times daily.

Randomised double-blind trial of bromovinyldeoxyuridine (BVDU) and trifluorothymidine (TFT) in dendritic corneal ulceration.

The results of a randomised double-blind clinical trial of 0.1% bromovinyldeoxyuridine (BVDU) and 1% trifluorothymidine (TFT) in 60 patients with corneal dendritic ulceration are presented. There was no significant difference between BVDU and TFT in terms of numbers of ulcers healed (p = 0.61), mean healing time (p = 0.065), and cumulative healing rate (p = 0.058). No serious side effects were observed, though transient stinging was recorded in five patients receiving TFT and in three patients receiving BVDU. One patient in the group treated with TFT developed a punctate epitheliopathy.