MATERIALS AND METHODS: Twenty-two fresh cadavers (forty-four knees) were dissected by randomisation under the block of four technique, and two different incisions were performed for each knee. Exploration was performed from the skin incision to the IPBSN around the incision zone. If the discontinuity of the nerve was found, it was classified as IPBSN injury. The anatomic measurement was performed. The IPBSN injury between two groups were analysed with the chi-square test.
RESULTS: The risk of IPBSN injury in the oblique group was 2 from 22 knees (9.1%), and 12 knees from 22 knees (54.5%) in the vertical group (P=0.001). Most common number of branch(es) found, is one branch, the horizontal distance ranged from 2.6cm to 8.5cm (average 5.7±1.6), the vertical distance ranged from 4.4cm to 12.6cm (average 7.6±1.9) and the declination angle ranged from 6° to 87° (average 34.7±24.3).
CONCLUSION: The risk of the IPBSN injury in oblique skin incision may be less than the vertical incision in the medial opening wedge HTO.