Complication rate following high tibial open-wedge osteotomy with spacer plates for incipient osteoarthritis of the knee with varus malalignment.

PURPOSE: Medial open-wedge high tibial osteotomy (HTO) with spacer plates is recommended to correct varus malalignment of the knee with symptomatic overload of the medial compartment.
METHODS: Fifty-five knees in 50 patients were assessed. Intra- and post-operative complications were recorded, and Tegner, Lysholm and IKDC scores were used to evaluate functional results. Radiological parameters consisted of medial proximal tibial angle (aMPTA), femorotibial angle (aFTA), posterior proximal tibial angle, lateral distal femur angle, mechanical axis deviation (MAD) and osteoarthritis score (Jäger and Wirth).
RESULTS: Duration of follow-up was 5.0 ± 1.4 years. Overall and implant-related complication rates were 27.3 and 10.9 %, respectively. No statistical association could be detected between overall and implant-related complication rates and age, gender, wedge size, angle of correction or body mass index. Mean improvement in Lysholm score was 26.8. Overall IKDC scores at follow-up were A25, B26, C2 and D2. Post-operative correction of MPTA and FTA averaged to 89.6° and 173° and to 89° and 173.5° at follow-up, respectively. Initial MAD of 21.8 mm was corrected to 11.8 mm at follow-up. Osteoarthritis score increased from 1.4 ± 0.9 to 1.9 ± 0.9 points.
CONCLUSIONS: HTO with spacer plates improves knee function and is an effective procedure in selected patients. Overall and implant-related complication rates should be considered and seem to be lower with a smaller angle of correction corresponding to incipient osteoarthritis and less varus deformity. LEVEL OF EVIDENCE: Retrospective case series, Level IV.