The articular cartilage of the patella was studied in 100 knees at necropsy. In twenty-one of these knees the cartilage changes were related to the trabecular architecture of the underlying bone. It would appear that the initiation and location of cartilage damage and its rate and degree of progression are related to the relative stiffness of the underlying cancellous bone. On the basis of our observations we suggest that the diagnosis "chondromalacia of the patella" should be reserved for patients with asymptomatic or transiently symptomatic fibrillation of the articular cartilage of the central medial patellar facet. Those patients with persistent patellofemoral pain should be considered to have some other syndrome.

Disc degeneration starts as an avascular necrosis. In the lower lumbar area the discs deteriorate early because of mechanical stresses. During certain early periods of degenerative changes a mechanical disorder between the annulus and the posterior longitudinal ligament may cause tiredness and pain. When the disc is completely degenerated and has lost its physical properties backache disappears.

We reviewed 44 consecutive revision hip replacements in 38 patients performed using the cement-in-cement technique. All were performed for acetabular loosening in the presence of a well-fixed femoral component. The mean follow-up was 5.1 years (2 to 10.1). Radiological analysis at final follow-up indicated no loosening of the femoral component, except for one case with a continuous radiolucent line in all zones and peri-prosthetic fracture which required further revision. Peri-operative complications included nine proximal femoral fractures (20.4%) and perforation of the proximal femur in one hip. In five hips wiring or fixation with a braided suture was undertaken but no additional augmentation was required. There was an improvement in the mean Japanese Orthopaedic Association score from 55.5 (28 to 81) pre-operatively to 77.8 (40 to 95) at final follow-up (p < 0.001). Revision using a cement-in-cement technique allows increased exposure for acetabular revision and is effective in the medium term. Further follow-up is required to assess the long-term results in the light of in vitro studies which have questioned the quality of the cement-in-cement bond.

In 44 consecutive patients, 60 porous-coated anatomic total knee (PCA) prostheses with a porous-coated central tibial stem were implanted without using cement. The clinical results and bony remodelling have been assessed after five years' follow-up. The average Hospital for Special Surgery knee score was 33.1 before operation and 95.7 at the latest follow-up, while the average range of movement improved from 63 degrees to 123 degrees. No subsidence or migration of the components was seen. A radiodense line appeared around the components at six months to one year after the operation and became more dense with time. There was no evidence of bone resorption related to stress-shielding in the tibial plateau

Four cases are described of solitary spinal neurofibroma, a rare tumour of the spinal cord or nerve roots. Computerised tomography provided an accurate topographical definition of the tumour. Magnetic resonance imaging showed an increased T2-weighted signal and multiple areas of decreased T1- and T2-weighted signals centrally. The MR signals matched the histological examination which showed hyperplastic interfascicular connective tissue, pleomorphic cells, and tightly packed nerve fibres compressed by the surrounding loose connective tissue. Electron microscopy showed three types of cell: Schwann cells, fibroblast-like cells, and mast cells. The histological findings suggests that solitary spinal neurofibroma is a distinct pathological entity which could be diagnosed preoperatively from the MR images.

We review 210 Stanmore knee replacements in 163 patients to assess the survival of the prostheses and the long-term results. The annual rate of failure reached a maximum of 4.6% in the fourth year after operation; thereafter it declined to reach zero by the eighth year. Between two and eight years after operation, 66.3% of the surviving knees were completely free of pain and 30.2% had mild retropatellar pain. Fixed flexion deformities present before operation were completely corrected in 73% of the knees, and varus or valgus deformities were invariably corrected. Stability was always restored to unstable knees and 80.8% of knees flexed to 90 degrees or more after replacement. Aseptic loosening (8.1%), prosthetic infection (4.3%) and femoral fracture (2.9%) led to 8.5% of the prostheses being revised or removed over eight years. Modifications in prosthetic design and operative techniques have been introduced to minimise such complications in the future.

A control system for a multifunctional hand prosthesis, which requires a minimum of training for the amputee, has been developed. The great advantage of the pattern recognition technique in making it possible to control as many as six prosthetic movements has prompted this study. The development of a complete miniaturised system has allowed a clinical trial on four patients. Two different tests have been employed to evaluate this system: an objective computer test and a test representing activities of daily living (ADL test). The computer test shows that a high rate of correct recognition is obtained immediately after the prosthesis is applied to the amputee. The ADL test shows that forearm rotation, and flexion and extension of the wrist are used in most activities, indicating that few compensatory movements are performed. It is suggested that this control system is feasible and that long periods of training are unnecessary.

1. Thirty-four patients with severe lumbo-sacral subluxation have been studied. Twenty-nine of these came for advice between the ages of nine and nineteen, and of these, twenty-five developed symptoms and signs of a characteristic syndrome.

2. The details of the syndrome are described: the essential features are spinal stiffness, a lordotic gait, resistance to straight leg raising, and in some cases evidence of interference with cauda equina or nerve root.

3. The danger of attempted reduction by traction is stressed, as well as the difficulties to be encountered during posterior lumbo-sacral fusion.

4. The reasons for operating are given; the results of spinal fusion were satisfactory.

5. The traditional apprehension concerning the effect of severe subluxation on childbirth has probably been over-stressed.

6. The tendency to slip was almost completely arrested by spinal fusion.

This prospective study compares the outcome of 157 hydroxyapatite (HA)-coated tibial components with 164 cemented components in the ROCC Rotating Platform total knee replacement in 291 patients. The mean follow-up was 7.6 years (5.2 to 11). There were two revisions for loosening: one for an HA-coated and one for a cemented tibial component. Radiological evaluation demonstrated no radiolucent lines with the HA-coated femoral components. A total of three HA-coated tibial components exhibited radiolucent lines at three months post-operatively and these disappeared after three further months of protected weight-bearing. With HA-coated components the operating time was shorter (p <  0.006) and the radiological assessment of the tibial interface was more stable (p < 0.01). Using revision for aseptic loosening of the tibial component as the end point, the survival rates at nine years was identical for both groups at 99.1%.

Our results suggest that HA-coated components perform at least as well as the same design with cemented components and compare favourably with those of series describing cemented or porous-coated knee replacements, suggesting that fixation of both components with hydroxyapatite is a reliable option in primary total knee replacement.