[EFFECTIVENESS OF HIGH TIBIAL OSTEOTOMY ASSISTED BY THREE- DIMENSIONAL PRINTING TECHNOLOGY FOR CORRECTION OF VARUS KNEE WITH OSTEOARTHRITIS].

Objective: To evaluate the effectiveness of high tibial osteotomy (HTO) assisted by three-dimensional (3-D) printing technology for correction of varus knee with osteoarthritis.

Methods: Between January 2014 and June 2015, 16 patients (20 knees) with varus knee and osteoarthritis underwent HTO assisted by 3-D printing technology; a locking compression plate was used for internal fixation after HTO. There were 6 males and 10 females, aged 30-60 years (mean, 45.5 years). The disease duration was 1-10 years (mean, 6.2 years). The unilateral knee was involved in 12 cases and bilateral knees in 4 cases. According to Koshino's staging system, 3 knees were classified as stage I, 7 knees as stage II, 8 knees as stage III, and 2 knees as stage IV. Preoperative Hospital for Special Surgery (HSS) knee score was 63.8 ± 2.2; the femorotibial angle was (184.8 ± 2.9)°; and Insall-Salvati index was 1.03 ± 0.13.

Results: All the wounds healed primarily, and no complication of infection, osteofacial compartment syndrom, or deep vein thrombosis was observed. All patients were followed up 6-18 months (mean, 12.6 months). Personal paralysis was observed in 1 case (1 knee), and was cured after expectant treatment. Bone union time was 2.7-3.4 months (mean, 2.9 months). At 6 months after operation, the femorotibial angle was (173.8 ± 2.0)°, showing significant difference when compared with preoperative one (t = 11.70, P = 0.00); Insall-Salvati index was 1.04 ± 0.12, showing no significant difference when compared with preoperative one (t = -0.20, P = 0.85); and HSS knee score was significantly increased to 88.9 ± 3.1 (t = -25.44, P = 0.00). At last follow-up, the results were excellent in 13 knees, good in 6 knees, fair in 1 knee, and the excellent and good rate was 95%.

Conclusion: 3-D printing cutting block can greatly improve the accuracy of HTO, avoid repeated X-ray and multiple osteotomy, shorten the operation time, and ensure better effectiveness for correction of varus knee with osteoarthritis.