Our aim was to compare the degree of patellar descent and alteration in angle of the inclination of the tibial plateau in lateral closing-wedge and medial opening-wedge high tibial osteotomy (HTO) in 51 consecutive patients with osteoarthritis of the medial compartment and varus malalignment. Patellar height was measured by the Insall-Salvati (IS) and the Blackburne-Peel (BP) ratios. The tibial inclination was determined by the Moore-Harvey (MH) method. Multivariate linear regression analysis was used to determine the influence of the type of HTO (closing vs opening wedge) on the post-operative patellar height or tibial inclination. The intra- and interobserver variability of these methods was determined before operation and at follow-up at one year. After an opening-wedge HTO the patellar height was significantly more decreased (mean post-operative difference: IS = 0.15; 95% confidence interval (CI) 0.06 to 0.23; BP = 0.11; 95% CI 0.05 to 0.18) compared with a closing-wedge HTO. The angle of tibial inclination differed significantly (mean post-operative difference MH = -6.40 degrees; 95% CI -8.74 to -4.02) between the two HTO techniques, increasing after opening-wedge HTO and decreasing after closing-wedge HTO. There was no clinically-relevant difference in the intra- and interobserver variability of measurements of patellar height either before or after HTO.

From 1986 until 1995 we used the BurchSchneider anti-protrusio cage in 31 patients (33 hips) and followed the patients for 5 years. Five patients died within the 5-year follow-up. Clinical outcome listed an average Harris hip score of 71/70/66 points after 1, 2 and 5 years respectively. One patient had a revision due to late-onset haematogenous infection. We found cup migration in nine patients. Migration was self-limiting in three cases and in two there was no bony graft ingrowth. Screw breakage was seen in one case. All migrated cages showed a higher rotational centre than cages without migration.Résumé Entre 1986 et 1995 nous avons utilisé l'anneau anti-protrusion de Burch Schneider chez 31 malades (33 hanches) qui ont été suivis 5 années. Cinq malades sont morts dans ce délai. Le résultat clinique donne un score moyen de Harris de 71/70/66 points après respectivement 1, 2 et 5 années. Un malade a eu une révision à cause d'une infection hématogène à début tardif. Nous avons trouvé une migration de la cupule chez 9 malades. La migration s'était limitée spontanément dans trois cas. Dans deux cas il n'y avait aucune réhabitation de la greffe. Une rupture de la vis a été vue dans un cas. Toutes les cupules ayant migré avaient un centre rotationnel plus haut situé que les cupules sans migration.