Abstract
The purpose of this study was to investigate whether the location of the hinge affects
the incidence of hinge fracture during medial closing-wedge distal femoral varus osteotomy
(DFVO). Twenty knees from 10 fresh-frozen human cadavers (mean age, 75 ± 17 years)
were used to perform uniplanar medial closing-wedge DFVO with a 7-mm wedge. Each specimen
was randomly assigned to either group A (supracondylar hinge) or group B (lateral
condylar hinge). The incidence of hinge fracture and stability was compared between
both groups after uniplanar medial closing-wedge DFVO. In group A, 8 of 10 knees had
a lateral cortex fracture during closure of the osteotomy gap, and all fractured knees
were unstable. Two knees with an intact lateral cortical hinge showed stability under
manual valgus and varus forces. After intentional breakage of the lateral cortical
hinge, both knees were found to be unstable under the same force. In group B, 2 of
10 knees had a lateral cortex fracture, and 8 knees had no fractures. All specimens
were found to be stable under manual valgus and varus forces. After intentional breakage
of the lateral cortical hinge in group B, 2 knees were unstable, while 8 knees remained
stable. This study showed a significantly higher incidence of lateral cortical hinge
fracture and instability in group A than in group B during closure of the osteotomy
gap.
Keywords
femur - knee - osteotomy - hinge fracture - osteoarthritis
