The uncemented Bicontact total hip arthroplasty in octogenarians. Medium-term results.

Uncemented total hip arthroplasty was developed on the principle of biological fixation to enhance longevity of the prosthesis. Though the role of uncemented total hip replacement as an alternative is well accepted in young patients, its role in elderly remains controversial. We reviewed a consecutive series of 60 uncemented Bicontact total hip arthroplasties in 51 octogenarian patients with a mean follow-up of 7 (range 5-9) years. Mean patient age was 87.8 (range 80-97) years. Mean preoperative Harris hip score of 48 (range 32-65) improved postoperatively to a mean of 88 (range 58-94). There were 26 hydroxyapatite (HA) and 34 non-HA plasma pore-coated acetabular cups; one cup was revised for recurrent dislocation. Radiological evaluation revealed no unstable cups; however, two were "probably unstable" (one non-HA and one infection in an HA-coated cup) and two "possibly unstable" (one HA and one non-HA cup) ( P <0.05). None of these cups were clinically symptomatic. Two femoral stems were considered "possibly unstable" and one stem "fibrous stable", while the remaining stems were "osseo-integrated". There were no revisions of either femoral stem or cup for aseptic loosening. Using the recommendation of revision as the end point, cumulative prosthesis survival rate was 98.4% at a mean follow-up of 7 years (95%CI: 95.9-99.4%). However, cumulative survival with revision being the end point for aseptic loosening was 100% for the Bicontact prosthesis. Results of our series are encouraging and justify the continued use of this prosthesis in the elderly.

Transvertebral pedicle fixation in severe grade spondylolisthesis. Report of three cases.

The ideal treatment for spinal stabilization of Myerding Grade III-IV spondylolisthesis remains controversial, with a variety of techniques having been described. The authors report on a consecutive series of three adult patients with high-grade slippage who were treated with transvertebral pedicle fixation and standard spinal instrumentation, as both primary and revision procedures. There were no complications from the procedure, and a good outcome was achieved in all patients. The results at 4- to 8-year follow-up review are presented. This is a relatively simple and safe method of achieving spinal stabilization, which bypasses some of the problems caused by the associated anatomical distortion in high-grade spondylolisthesis and has good results at midterm follow up.

Epidurography in the management of sciatica.

Fifty consecutive patients starting treatment for sciatica with epidural injections of steroid and local anaesthetic underwent concomitant epidurography. The prognostic potential of this combination was investigated. Epidurography was confirmed as a safe out-patient procedure. Incorrect needle siting accounted for five total and two partial failures. The procedure was found to be a sensitive investigation, 36 showing definite abnormalities. It was of particular value in the diagnosis of lateral canal stenosis. However, it was found to have no prognostic value. For 12 of 16 patients requiring invasive therapy, it was considered that epidurography would have obviated later radiculography had the results been known. It is suggested that the combination of this out-patient investigation with the last of three epidural anaesthetic injections in patients whose symptoms persist, represents an improvement in management both financially and in terms of patient convenience.

The effect of postural changes on the inferred pressures within the nucleus pulposus during lumbar discography.

By observing the variation of intradiscal pressure occurring at different body postures, it is possible to infer a functional hydrostatic behavior of a lumbar disc. Results from such observations on normal discs are already available. However, observations on degenerate discs are largely restricted to in vitro studies. The authors are now able to report a series of recordings taken from discographically degenerate lumbar discs in patients presenting with low-back pain. In this study of twenty patients, pressure observations were made on 21 normal and 19 abnormal discs. From the results that the authors have obtained, they can reaffirm that normal discs behave predictably and as previously described. The abnormal discs, however, did not behave as a single group. They showed patterns of pressure changes in different postures often dissimilar from that shown by the normal discs both in the absolute values recorded and the sequential changes that occur during the postural change. Unfortunately, the authors were unable to correlate either the extent or character of disc degeneration with the observed variation in pressure changes.

Flexion and extension radiography of the lumbar spine: a comparison with lumbar discography.

Four methods of quantifying relative intervertebral body movement from static flexion/extension radiographs are reviewed and the ability of each of these techniques to indicate the site(s) of disc degeneration is compared with that of lumbar discography. Of the methods examined, that of measuring the linear displacement of one vertebra in the antero-posterior plane was found to be the most accurate method of indicating disc degeneracy. None of the methods examined was free from artefacts. With regard to the clinical usefulness of flexion/extension radiography, we discuss two separate situations. Firstly, the taking of a single set of flexion/extension radiographs is concluded to be of little value in the management of patients with low back pain. Secondly, flexion/extension radiography, on a serial basis, is considered to be of possible value in specific situations (for example, follow-up of a spinal fusion).

The use of in vivo lumbar discography to assess the clinical significance of the position of the intercrestal line.

An investigation of the clinical relevance of the location of the intercrestal line in relation to the pattern of disc degeneration in the lower lumbar spine is presented. An analysis of the discograms from 89 symptomatic patients has demonstrated a difference in the incidence of disc degeneration in the L4-5 and L5-S1 disc spaces dependent on the position of the intercrestal line. This difference supports the hypothesis that additional protection will be given to those L5-S1 discs with which high intercrestal lines are associated as compared to those associated with intercrestal lines lying lower down the spine. A corollary of this hypothesis is that for any individual there is an increased likelihood that the L4-5 disc space will undergo degeneration from the influence of normal mechanical stresses before the L5-S1 disc space if the intercrestal line lies comparatively high up the spine.

Observations of pressures within normal discs in the lumbar spine.

As a result of performing pressure standardised lumbar discography, in vivo pressure measurements within lumbar discs have been recorded. Our results support the theory that for normal discs, the internal pressure within the nucleus pulposus increases when the subject changes from lying prone to standing and thence to sitting. However, when comparing our results with other published data, we consistently show a reduction in the absolute values recorded. We discuss the possible reasons for this discrepancy. Arguments have been advanced in the literature both for and against the nucleus in a normal disc behaving hydrostatically. An hypothesis which occupies the middle ground between these two concepts is proposed which could well be consistent with all the published data including our own.

The significance of osteophytes on lumbar vertebral bodies in relation to discographic findings.

Marginal osteophytes of the lumbar vertebral bodies have been related to the discographic findings in lumbar disc spaces. Every case of Scheuermann's anterior marginal epiphysitis was associated with a direct communication with the disc nucleus. Eleven per cent of discs with related 'traction' spurs were discographically normal Forty-three per cent of discs with related 'claw-type' osteophytes appeared normal with discography. It is concluded that when reported radiographs of the lumbosacral spine with osteophytes, particularly those of the claw-type, it is incorrect to describe these changes as representative of disc degeneration in the absence of unequivocal disc space narrowing.

Some experimental observations of the influence of a single lumbar floating fusion on the remaining lumbar spine.

Observations of the ranges of flexion of the lumbar interbody joints under standardized loading have been made before and after isolated floating fusions were performed. The observed effect was that the movement which had previously occurred at the free disc level was transferred preferentially to discs immediately adjacent to the fusion-usually, but not always, most of this movement being taken up by the disc immediately below the fusion. The implications of these observations for patients on whom a floating spinal fusion is to be performed are discussed. A clinical case is discussed in which a congenital fusion is associated with degeneracy of an immediately neighboring disc.

Pressure standardized lumbar discography.

The basic procedure for carrying out clinical lumbar discography has been examined. As a consequence, a pressure-standardized injection technique has been established. It is shown that monitoring the flow of contrast medium into the disc can, in the case of a true nuclear injection, improve the diagnostic efficiency. Additionally, knowledge of this flow can help to avoid a commonly occurring, but not often recognized, artefact described in detail elsewhere (Quinnell and Stockdale, 1980).

An investigation of artefacts in lumbar discography.

An artefact of lumbar discography which can confuse or negate delineation of the nucleus pulposus is presented. This artefact is the inadvertent injection of contrast medium into a cavity which is not the true nuclear cavity. A positive diagnosis cannot be made in this situation, normality has not been proven and, in particular, the presence of a protrusion of the nucleus through the annulus fibrosus may not have been demonstrated. Hypotheses are proposed to explain the occurrence of these artefactual injections.