A Clinical Study Of Changes In Rotational Alignment Of The Lower Limbs Following Opening Wedge High Tibial Osteotomy

Objective::This study evaluated the changes in rotational alignment of the lower limbs before and after open-wedge high tibial osteotomy(OWHTO)and compared the results according to whether there is a lateral hinge fracture(LHF).Methods::Thirty patients who suffered symptomatic medial compartment knee osteoarthritis underwent OWHTO from June 2017 to September 2019.Two patients(2 knees)loss to follow-up,and were excluded from the study,28 patients(34 knees)were included,The mean age of the patients at surgery was 48.7 years(range,22 to 64 years).Functional improvement was assessed by subjective International Knee Documentation Committee(IKDC)scores and Kujala Patellofemoral Scores.Pre-and postoperative Knee rotation angle(KRA),tibial torsion angle(TTA),tibial tuberosity–trochlear groove distances(TT-TGD)and The gap ratio(GR)were obtained.The authors analyzed radiological features and functional improvement between non-LHFs group and LHFs group.Results:The mean follow-up at 47.2±8.8 months(range,36-64 months).IKDC scores(64.97±9.43 vs 28.59±7.12;P<0.001)and kujala scores(80.29±6.82 vs 52.74±9.5;P<0.001)significantly improved.LHFs were observed in 7 knees(20.6%),All were Type ⅠLHF.The KRA significantly increased after OWHTO(2.3±2.3;P<0.001).The TTA significantly increased in LHFs group(2.2±1.6;P=0.001)but decreased in non-LHFs group(-2.2±0.7;P<0.001).The increment of TT-TGD(5.6±4.5 vs 2.2±1.2;P<0.001)in LHFs group was larger than that in non-LHFs group.The GR(1.3±0.5 vs 0.5±0.2;P<0.001)were significantly greater in LHFs group than in non-LHFs group.At the final follow-up,There was no significant difference in IKDC(63.7±10.0 vs 65.3±9.5;P=0.699)and Kujala(79.3±8.8 vs 80.6±6.4;P=0.668)scores between this two groups.Conclusion:OWHTO significantly improves the knee function in patients with knee osteoarthritis.External rotation of the tibia occurred after OWHTO.Increase of the TTA、GR occurred after type Ⅰ LHFs,with a 20.6% incidence of LHFs.There is no significant difference in the short-term clinical function in patients with type Ⅰ LHFs compared with those without LHFs,but the problems of delayed gap space healing should be noticed.