D-hole breakage of 2 angular stable locking plates for medial opening-wedge high tibial osteotomy: Analysis of results from 12 cases

An adequate stable fixation implant should be used for medial opening-wedge high tibial osteotomy (MOWHTO) to promote rapid bone healing without complications. To date, the highest fixation stability has been observed for angular stable locking plates. However, there is still little medical literature regarding breakage of these plates. The purpose of the present study was to report the results of plate breakage around D-hole with the use of both types of locking plate fixation for MOWHTO. Medical records of 12 patients who experienced plate breakage after MOWHTO with either a TomoFix or OhtoFix plate between August 2013 and August 2016 were retrospectively reviewed. A total of 12 patients (7 males and 5 females) who experienced plate breakage at the screw hole just above the osteotomy were evaluated (age, 63 ± 8 years; body mass index (BMI), 28 ± 2 kg/m(2); opening gap height, 12 ± 2 mm). There were 9 patients (75%) with plate breakage and loss of correction necessitating revision surgery, and 11 patients (92%) had lateral cortical hinge fractures postoperatively. Of the 9 patients with loss of correction necessitating revision surgery, 4 had a TomoFix plate and 5 had an OhtoFix plate. The only statistically significant association with broken plates lost reduction was the presence of lateral cortical hinge fractures (P = .003), but there was no significant association with age, gender, BMI, diabetes, smoking, plate type, opening gap height, and material used to fill the wedge. In addition, mean knee society score in the 12 patients was significantly higher postoperatively than preoperatively (P < .001). Since the amount of plate breakage was just over 1% and with only 12 in total, no true conclusion can be made with certainty. However, in the face of no lateral hinge or cortical disruption, there is a 99% success rate with the plate described. If the lateral hinge is disrupted, a restriction of activity or weight bearing may be needed.