A clinical and biomechanical study of cast-brace treatment of fractures of the femoral shaft

Abstract

This thesis reviews fracture treatment from early history to the beginning of the First World War; and treatment of fractures of the femoral shaft from then to the present day. A detailed review of the knowledge of fracture healing in relation to fractures of the femoral shaft is undertaken, with a look at the clinical implica¬ tions which provide a strong argument for cast-bracing. Other factors such as multiple injuries, financial aspects, the recovery of quadriceps function and the different materials and methods are reviewed. The background of the biomechanical aspects are discussed also. Early cast-bracing of fractures of the femoral shaft is shown to be clinically, physiologically and biomechanically a ■sound method of treatment.

The clinical study reviews retrospectively the treat¬ ment of these fractures by traction alone and by traction and cast-bracing of the first year of treatment during the years 1974 and 1975; and the experience of cast-bracing in the Orthopaedic Unit during 1976 and 1977. The first year's experience of a prospective study is also reviewed. The less than good results are correlated with any problems or errors in the technique so that they may be avoided in future. The biomechanical study evaluates the off-loading characteri sties of the cast-brace during stance in patients with femoral fractures alone and aged less than 50 years; in those with multiple injuries, and those aged over 50 years. To do this, strain gauged transducers were applied to the cast at the fracture level where it was circumferentiaily split, and to the hinges at the knee. They measured respectively the load transfer between the two portions of the thigh cast, and the thigh cast as a whole, and the below-knee cast; and by subtraction from the total limb load, the skeletal force at the fracture level, and the knee.

The clinical results compare favourably with other forms of treatment and with other reports of treatment by early cast-bracing. Fractures at all levels were treated successfully and the management of the multiply injured patient was enhanced. The results of the biomechanical study show that the load carried by the two portions of the thigh cast, and the thigh cast as a whole, was proportion¬ ately high at first and stabilised at from 20 to 501 of body weight. The effects of age and concommitant injuries is elucidated.

The biomechanical stability achieved by the brace allows early mobilisation and controlled active motion of the limb with a graded increase in load as union progressed which must be due to a physiological feed-back mechanism.

The physiological environment stimulates earlier union and recovery of soft tissue and joint function. The hospital service benefits financially, and the patient, physically, socially and financially.