We allocated randomly 27 patients undergoing 28 primary uncemented total hip replacements (THR) to receive prosthetic components of similar design with either plasma-sprayed titanium alloy (Ti) coating (n = 13) or hydroxyapatite (HA) coating (n = 15). After some exclusions, 15 of the patients (15 THR; 7 with HA- and 8 with Ti-coating) were followed by roentgen stereophotogrammetric analysis at 3, 6 and 12 months to measure migration of the femoral component. Twenty-six of the patients (26 THR) were followed clinically and by conventional radiography. All the femoral components had migrated at 3 months. From 3 to 12 months, the migration of Ti-coated components continued whereas the HA-coated components had stabilised. At 12 months there was significantly less migration of the HA-coated components (p < 0.05). The maximum subsidence was 0.2 mm in both groups. The Harris hip score was equal in the two groups preoperatively but at follow-up it was better in the HA-coated group (p < 0.05) and visual analogue scale scores showed that they had less pain (p < 0.05).

In a prospective study, 41 consecutive patients with a partial tear of the anterior cruciate ligament, diagnosed by arthroscopy, were reviewed after an average of 17 months, having been in plaster for six weeks after injury. Their average age was 29 years and review included clinical examination, measurement of anterior and posterior laxity with the Stryker knee laxity tester as well as evaluation of knee function and activity level. Twenty-one patients had unstable knees at follow-up; the mean total anteroposterior laxity for these patients was 12.6 +/- 3.9 mm compared with 7.1 +/- 4.3 mm for the normal knee. Most patients had few symptoms, but there was a significant reduction in the mean level of activity in the unstable group.