Showing papers by "Nuffield Orthopaedic Centre published in 1986"

Intervertebral disc mechanics: a review.

Abstract: Introduction Musculoskeletal problems account for up to 25% of general practitioner consultations1'2. Out of every 100 patients on the general practitioner's list, 4 will each year initiate a consultation for back pain3. Low back pain is responsible for over thirty million working days lost in Britain per annum4. Between 21%5 and 84%6 of such 'lumbago' occurs without a definite diagnosis, but it seems likely that degenerative disease of the spine underlies much of this absenteeism. Some occupations are affected more than others7. A study by the Royal College of Nursing8 reports the incidence of low back pain in nurses to be as great if not greater than amongst manual workers. Following skeletal maturation the spine begins to degenerate both biochemically and biomechanically, and this process continues throughout life at a rate which may be genetically predetermined9. Autoimmune mechanisms may also play a part in this process0'11. Degeneration occurs most rapidly at the L4/5 and L5/S1 levels. These are the levels subjected to the greatest mechanical stresses, so it is reasonable to assume that mechanical forces play a major role in disc degeneration. In this paper a number of mechanical influences on the disc, some physiological others pathological, will be considered (Table 1).

Effect of Surface Replacement Arthroplasty on Stability of the Ankle

Abstract: Loosening after total ankle arthroplasty may result from absorption of tensile and shear forces by relatively small bone-cement interfaces. A surface replacement arthroplasty similar in principle t...

Bones in muscles: the problems of soft tissue ossification.

Abstract: Extraskeletal osteogenesis, most often in muscles, is a rare and inexplicable event with serious clinical consequences [1]. It has many causes but there are two striking examples. The first is inherited, fibrodysplasia (myositis) ossificans progressiva (FOP), and the second acquired after neurological injury. In these cases ossification of the muscles is a clinical catastrophe which leads either to progressive rigidity from early life or compounds the disability of paresis. Investigation of the cause of myositis ossificans has until recently been limited and unrewarding, but this is to be expected whilst we remain so ignorant about the process of normal (skeletal) bone formation and have little idea about what determines phenotypic expression of the bone-forming cell, the osteoblast. However there is now considerable interest, for physiological and possible therapeutic reasons, in identifying and isolating those factors which induce osteogenesis. This research has relevance to ectopic ossification, of which the most extreme form occurs in fibrodysplasia ossificans progressiva [2, 3]. In this very rare condition (less than one per million of the population), regarded as one of the heritable disorders of connective tissue, progressive ossification within muscles is associated with constant and characteristic skeletal abnormalities, especially of the toes and cervical spine [4]. The severe disability reduces biological fitness close to zero and nearly all patients represent new autosomal dominant gene mutations [5]. The abnormal toes are present though often unrecognised, at birth, and ossification of the major muscles, particularly around the neck and spine, begins in infancy to affect about half the patients by the age of three years and all by adult life. Progressive disability results from fixation of the major joints: ossification in the muscles around the hips, often in later childhood or adolescence, is a major setback and may usher in a wheelchair existence. The cause of the ossification is unknown, but each event follows weeks after redness, swelling and pain in the affected muscle which initially suggests inflammation (hence the term 'myositis') or some rare alternative such as sarcoma. Limited histological studies show small round cell and fibroblastic infiltration of the oedematous muscle with myofibrillar fragmentation, followed by bone formation with both cartilage and bony elements. Because of the apparent involvement of the connective tissue within muscle the term 'fibrodysplasia' rather than 'myositis' is now a preferred alternative [1]. Although the episodes of 'myositis' may sometimes appear to follow injury, there is no other known reason for their occurrence. It is difficult to be certain that all such episodes are inevitably followed by ossification, but this is clearly the usual result. There is one obvious question; why in this heritable condition do the mesenchymal cells within the major muscles behave as if they are osteoblasts?

Ischaemic Contracture of the Intrinsic Muscles of the Hands a Hazard of Physical Restraint

Abstract: A case is described of bilateral ischaemic contracture of the intrinsic muscles of the hands, presenting in a mentally-disturbed patient one year after a reported period of immobilisation in a physical restraint device. Involvement of the deep thenar muscles and the interossei on the radial side of the hand can be explained by consideration of the anatomy of the deep palmar arch. Division of the tendons of the contracted interosseous muscles proximal to the metacarpophalangeal joints and release of the left first web improved hand function. Those who supervise the use of physical restraint devices should be aware of the risk of intrinsic muscle ischaemia and of the need for prompt diagnosis and treatment.

Treatment of giant cell tumour of the femoral head and neck.

Abstract: Giant cell tumours of the femoral head and neck treated at the Nuffield Orthopaedic Centre between 1970 and 1982 were reviewed to evaluate the effectiveness of primary treatment by curettage and bone grafting. All 4 cases recurred within two years, necessitating the likelihood of recurrence following curettage and bone grafting, particularly at this anatomical site, is stressed, and the possibility that hip replacement arthroplasty be considered the primary treatment of choice is discussed.

Dentine is biochemically abnormal in osteogenesis imperfecta.

Abstract: 1. In osteogenesis imperfecta the bones are brittle but the teeth, whose dentine contains the same genetic collagen as bone (type I), may be clinically normal. 2. To investigate this paradox we have measured the amino acid composition of insoluble dentine collagen from 16 deciduous and 18 permanent teeth in control subjects and in 59 patients with different forms of osteogenesis imperfecta. 3. In 55 of the patient samples significant differences from normal were found, especially in the number of lysine residues, and in the relative amounts of hydroxylysine to lysine. 4. These results demonstrate the high frequency of biochemical abnormalities in osteogenesis imperfecta. They also suggest that classifications of this disorder based on the presence or absence of clinical dentiogenesis imperfecta are likely to be unsound.

Dysplasia epiphysialis hemimelica of the hip. A case report.

Abstract: Dysplasia epiphysialis hemimelica most commonly presents as overgrowth of part of an epiphysis. A case of dysplasia epiphysialis hemimelica, presenting with hip pain secondary to an isolated epiphyseal exostosis of the femoral head, is reported. Excision of the osteochondroma produced complete relief of symptoms. This forme fruste of dysplasia epiphysialis hemimelica has not previously been described in the hip joint.

Abducted Little Finger in Low Ulnar Nerve Palsy

Abstract: Persistent abduction of the little finger after ulnar nerve palsy has been attributed to the unopposed action of extensor digiti minimi. Evidence is presented that the deformity can also result when re-innervation reaches abductor digiti minimi but not the palmar interossei. Operative correction of the deformity, if required, should be delayed until it is clear that no further muscle recovery is likely to occur.

Biomechanical Compatibility of Cruciate Ligament Prostheses

Abstract: An experiment was performed to determine the effects of stiffness of cruciate ligament prostheses upon joint function and degeneration. Twenty four sheep were allocated into four groups. One group had the ligament excised with no replacement and subsequent groups underwent substitution procedures with either a stiff, matched, or lax prosthesis. After six months the animals with a stiff or matched prosthesis were significantly less lame than those with a lax prosthesis or no prosthesis. However, at post mortem examination the animals with a stiff prosthesis or no prosthesis showed significantly more widespread cartilage damage than the matched or lax groups. The results indicate that either a stiff or matched prosthesis may restore functional activity, but that the stiff prosthesis may predispose to increased degenerative changes.