Table 3.

Intraoperative complications

Error	Clinical effect	Prevention	Detection	Remedy
Introducing anterior or posterior slope to the proximal tibia/tibial plateau during HTO [6]	If unwanted anterior or posterior slope is introduced, it may alter mechanics at the knee, accelerating arthritis, and negatively impacting pain and function. It also may lead to instability if there is cruciate ligament insufficiency. Can improve instability by changing slope to prevent anterior or posterior tibial translation.	Meticulously line up jig with native posterior slope of tibial plateau.	Intraoperative visual inspection, postoperative x-rays	If noted intraoperatively, may recut bone at more appropriate slope, but must avoid cutting too much bone.
Fracture [10]	Propagation of osteotomy through far cortex can destabilize proximal fragment, leading to possible nonunion. Propagation into the articular surface is even more severe because of potential articular incongruity.	Carrying apex of osteotomy cut to within 10 mm of far cortex and leaving the proximal fragment at least 15 mm thick. Gradual closure also permits stress relaxation of intact far cortex. No difference between medial opening wedge and lateral closing wedge in terms of maximal obtainable correction angle without failure of far cortex.	Heightened suspicion, intraoperative visual inspection, postoperative radiographs	Fractures must be appropriately reduced and stabilized
On removing bone wedge, leaving residual bone	May be encountered on compression of distal and proximal segments of the tibia after wedge is removed, if full compression is not achieved.	Meticulous removal of bone wedge and remaining fragments of bone	Compression may take up to 5 minutes for plastic deformation to occur. If compression and osteotomy closure are not achieved, reassess for bone fragments.	Resect remaining bone and remove it
Neurovascular injury on lateral proximal tibial dissection for lateral closing HTO [8]	Peroneal nerve is most at risk with osteotomy of the proximal fibula, where the nerve wraps around the neck of the fibula before dividing into the deep and superficial branches. The peroneal veins and anterior tibial vessels are close to the fibula in the upper half of its shaft.	Use blunt Hohmann retractor to protect neurovascular structures on dissecting the proximal tibiofibular capsule	Postoperative neurovascular check	Vascular repair/consultation, nerve repair, conservative management.

HTO = high tibial osteotomy.