Objective: To assess the Universal Spine System and Kaneda Anterior Scoliosis System. Does one system have particular advantages over another?

Design: A retrospective review of patients with idiopathic scoliosis undergoing anterior fusion and instrumentation. The patients undergoing USS instrumentation were treated between 1994–1998, KASS patients 1997–2001.

Subjects: Thirty two consecutive patients were reviewed. Seventeen patients were in the USS group and 15 in the KASS group, 28/32 were female.

Outcome measures: Preoperative and postoperative radiographs, ISIS scans, and patient review. The in-patient notes were assessed for duration of surgery, blood loss, hospital stay and complications. Correction of Cobb angle and union were assessed.

Results: The patients in the KASS group had less flexible curves (correctability 45% vs. 53%). Despite this correction of Cobb angle was better in patients undergoing KASS instrumentation (38.0 degrees vs. 27.8 degrees, P=< 0.05). The secondary curves also improved more in the KASS group (55% vs. 29%, p=< 0.05). Complications occurred in 30%, but there was no difference between the two groups. There were no non-unions. In every other respect there was no difference between the groups for surgery time, blood loss, loss of correction or progression of secondary curve.

Conclusions: KASS instrumentation has better ability to correct spinal deformity in the short term. Further follow-up is required to assess long term results.

Objective: To assess early results with the KASS system for scoliosis correction. To assess lateral curvature, rotational correction and complications.

Design: The first 22 patients requiring anterior correction of scoliotic curves were retrospectively reviewed. Pre- and post-operative curve measurements were made with a Cobbometer. Topographical assessment (ISIS) scan was used to assess rotation and correction of the rib hump. The notes were reviewed to determine complications and time to discharge.

Subjects: Twenty-two patients: 18 idiopathic scoliosis (4 others); average age 15.4 years; 5 King One, 10 King Two, 6 King Three and one non-definable; 5 thoracic curves

Results: Average pre-op scoliosis 54.85 degrees

Average post-op scoliosis 19.4 degrees. Average correction 65%. One patient required second operation for long screws. Four self limiting rninor complications. Average time to discharge eight days

Conclusion: KASS instrurnentation is a safe, effective and reliable method to correct scoliotic curves including rotational deformities. It was not possible to correct the Cobb angle of purely thoracic curves as much as thoracolumbar curves. Cosmetic correction however has been excellent as demonstrated with ISIS. Long term review will be necessary to confirm that correction is maintained.

Instability may present at a different level after successful stabilisation of an unstable segment in apparently isolated injuries of the cervical spine. It can give rise to progressive deformity or symptoms which require further treatment. We performed one or more operations for unstable cervical spinal injuries on 121 patients over a period of 90 months. Of these, five were identified as having instability due to an initially unrecognised fracture-subluxation at a different level. We present the details of these five patients and discuss the problems associated with their diagnosis and treatment.

We used a rabbit model to investigate the mechanism by which the angulation of fractures is corrected in children. We produced a transverse proximal tibial fracture in one leg of 12 eight-week-old New Zealand white rabbits and measured bone alignment and length and the patterns of bone growth and remodelling.

The angle between the joint surfaces changed rapidly to correct the alignment of the limb as a result of asymmetrical growth of epiphyseal plates. In an adult with closed plates, the angle between the joint surfaces cannot therefore improve. The angle at the fracture itself showed slow improvement because of bone drift and the asymmetrical growth of the epiphyseal plates. Remodelling corrected the shape of the bone in the region of the fracture.

Periosteal division on the convex side increased the growth of the epiphyseal plate on that side, thus slowing the correction. The effect was relatively small, providing an indication that factors other than the periosteum are important in inducing correction.

External torsional deformities developed because of helical growth at the plate. This was probably caused by abnormal posture which induced a torque at the growth plate. Helical growth is the mechanism by which rotational deformities can occur and correct.

We reviewed the results of 545 consecutive total hip replacements using a cementless non-coated high-density polyethylene acetabular component combined with a cemented Muller stem at five to 10 years. In all, 421 patients (445 hips) were available for review, 118 by questionnaire and 303 by examination and radiography. Of these, 86% had a good or excellent result. We found a high rate of radiological loosening of the cup after the sixth year, and a high rate of clinical loosening after the eighth year. Loosening was commoner in women, in younger patients and where a smaller size of acetabulum had been used. Calcar resorption was significantly related to loosening of the acetabulum. Loosening appeared to be mainly due to polyethylene debris produced by micro-movement of the acetabulum against the bone, which had resulted in a giant cell foreign body reaction and subsequent bone erosion. We have abandoned the use of this prosthesis and suggest that direct contact between bone and polyethylene should be prevented by a coating of metal or some other material.

We subjected the proximal tibial growth plates of six-week-old rabbits to either compression or distraction of 1 kg on both legs. On one side the proximal tibial periosteum was divided circumferentially and stripped for 1 cm. After six weeks, growth was measured at both proximal and distal growth plates. Compression inhibited total tibial growth and distraction enhanced it. The compressed growth plate grew less and the distracted growth plate grew more, but there was a reciprocal change at the other end of the bone. Periosteal division enhanced growth at the adjacent growth plate but inhibited it distally; the effect of distraction was enhanced and that of compression reduced. We found reciprocal growth rates at the proximal and distal growth plates. Relatively small amounts of compression or distraction did affect total bone growth. Periosteal division appeared to induce overgrowth at least partly by a mechanical effect; it may be useful as an adjunct to other methods of leg lengthening, though not to epiphyseolysis.