The continued value of clinical and radiological surveillance: the Charnley Elite Plus hip replacement system at 12 years.

We report the follow-up at 12 years of the use of the Elite Plus total hip replacement (THR). We have previously reported the results at a mean of 6.4 years. Of the 217 patients (234 THRs), 83 had died and nine had been lost to follow-up. The patients were reviewed radiologically and clinically using the Oxford hip score. Of the 234 THRs, 19 (8.1%) had required a revision by the final follow-up in all but one for aseptic loosening. Survivorship analysis for revision showed a survival of 93.9% (95% confidence interval (CI) 89.2 to 96.5) at ten years, and of 88.0% (95% CI 81.8 to 92.3) at 12 years. At the final follow-up survival analysis showed that 37% (95% CI 37.3 to 44.7) of the prostheses had either failed radiologically or had been revised. Patients with a radiologically loose femoral component had a significantly poorer Oxford hip score than those with a well-fixed component (p = 0.03). Radiological loosening at 6.4 years was predictive of failure at 12 years. Medium-term radiographs and clinical scores should be included in the surveillance of THR to give an early indication of the performance of specific implants.

Chewing side preferences in children.

The dentition of 57 children aged 6-8 years old was examined clinically and radiographically. Subjects were divided into groups according to state of the dentition: caries free, no pathology and no pain; caries, no pathology and no pain; caries, pathology and no pain; caries, pathology and pain. The existence of a preferred chewing side (PCS) was determined using a visual spot-checking method. Subjects were instructed to chew gum on their posterior teeth. After 15 s the position of the chewing gum was recorded as right or left. This procedure was carried out seven times consecutively. Subjects had an 'observed preferred chewing side' (OPCS) when they chewed 5/7, 6/7 or 7/7 times on the same side. To determine if children were aware of their chewing side preference each subject's stated PCS was then recorded as left, right or none. 'Coincidence' between stated and OPCSs was said to occur if the stated PCS corresponded to the OPCS. Seventy-seven per cent of children had a PCS. The majority (70%) of caries free children also had a PCS (P < 0.05). The percentage with an OPCS varied from 70% of the caries free group to 92% of the group with caries, pathology and pain. However, there was no statistically significant association between state of the dentition and the presence of a PCS. Coincidence occurred in 56% of children. There was a statistically significant association between state of the dentition and coincidence (P=0.02). Children in pain were most likely to show coincidence (kappa=0.81).

The sulcus angle and malalignment of the extensor mechanism of the knee.

Anterior knee pain due to dysplasia of the extensor mechanism is common. We have studied 137 knees (103 patients) in order to identify a rapid and reproducible radiological feature which would indicate the need for further analysis. Overall, 67 knees (49%) had at least one radiological abnormality; 70 (51%) were considered normal. There were five cases of Dejour type-3 dysplasia of the femoral trochlea, nine of type-2 and 12 of type-1. There were 49 cases of patella alta and five of patella infera. Four knees had an abnormal lateral patellofemoral angle (patellar tilt), and in 15 knees there was more than one abnormality. Classification of trochlear dysplasia was difficult and showed poor reproducibility. This was also true for the measurement of the lateral patellofemoral angle. Patellar height was more easily measured but took time. The sulcus angle is an easily and rapidly measurable feature which was reproducible and was closely related to other features of dysplasia of the extensor mechanism. The finding of a normal sulcus angle suggested that seeking other radiological evidence of malalignment of the extensor mechanism was unlikely to reveal additional useful information. The severity of other features of dysplasia of the extensor mechanism correlated with increasing sulcus angle.