Improved surgical techniques and new fixation methods have revived interest in high tibial osteotomy surgery in recent years. Our aim was to review our first 59 cases. All patients underwent radiological and clinical review including pre and post operative scores.

Mean age at surgery was 43 (22-59) and mean follow up is 22 months.

The mean pre-operative limb alignment was 5.4° varus (range 1°-16°) with correction to 2° valgus (range -1° - 7°).

HTO is known to increase tibial slope and in this series the change in tibial slope from -5.2° (95%CI: -6.36 to -4.07)) to -7.8° (-8.83 to –6.89) was statistically significant. p= 0.0014 (Mann Whitney).

Patellar height is often reduced following opening wedge HTO and this is confirmed in our series. The Blackburne-Peel ratio changed from 0.74 to 0.58 and the Caton-Descamps from 0.83 to 0.7. Both were statistically significant at p<0.0001 and p=0.0001 respectively.

All scores improved post operatively, the knee injury and osteoarthritis outcome (KOOS) from 48 (8-91) to 73 (27-96), the Oxford knee score (OKS) from 25 (3-47) to 37 (9-48), and the EQ5D from 189809 (11221-32333) to 14138 (11111-22233) with the EQ5D VAS improving from 58 to 75. There was no correlation between change in limb alignment, tibial slope or patellar height and any of the scores used.

There were three superficial wound infections, and one non union which was treated with grafting and re fixation. Six patients have had their plate removed.

Improvement in clinical scores in these patients confirms that medial opening wedge HTO is a reliable joint preserving procedure in the short term and our surgical technique is reproducible and consistent with other published series.