[Effectiveness of distal femoral osteotomy assisted by three-dimensional printing technology for correction of valgus knee with osteoarthritis].

Objective: To evaluate the effectiveness of distal femoral osteotomy aided by three-dimensional (3D) printing cutting block for correction of vaglus knee with osteoarthritis. Methods: Between January 2014 and January 2016, 12 patients (15 knees) with vaglus deformity and lateral osteoarhritis underwent medial closing wedge distal femoral osteotomy. There were 5 males and 7 females, aged 30-60 years (mean, 43.8 years). The mean disease duration was 6.6 years (range, 1-12 years). The unilateral knee was involved in 9 cases and bilateral knees in 3 cases. According to Koshino's staging system, 1 knee was classified as stage I, 9 knees as stage II, and 5 knees as stage III. The X-ray films of bilateral lower extremities showed that the femorotibial angle (FTA) and anatomical lateral distal femoral angle (aLDFA) were (160.40±2.69)° and (64.20±2.11)° respectively. Mimics software was used to design and print the cutting block by 3D printing technique. During operation, the best location of distal femoral osteotomy was determined according to the cutting block. After osteotomy, internal fixation was performed using a steel plate and screws. Results: All incisions healed primarily; no complication of infection or deep vein thrombosis was observed. All patients were followed up 6-18 month (mean, 12.2 months). At 6 months after operation, the hospital for special surgery (HSS) score for knee was significantly improved to 89.07±2.49 when compared with preoperative score (65.27±1.49, t=-28.31, P=0.00); the results were excellent in 10 knees, good in 4 knees, and fair in 1 knee with an excellent and good rate of 93.3%. The bony union time was 2.9-4.8 months (mean, 3.3 months). Bone delayed union occurred in 1 case (1 knee). The postoperative FTA and aLDFA were (174.00±1.41)° and (81.87±1.06)° respectively, showing significant differences when compared with preoperative ones ( t=-18.26， P=0.00; t=-25.19, P=0.00). The percentage of medial tibial plateau in whole tibial plateau was 49.78%±0.59%, showing no significant difference when compared with intraoperative measurement (49.82%±0.77%, t=0.14, P=0.89). Conclusion: 3D printing cutting block can greatly improve the accuracy of distal femoral osteotomy, and ensure better effectiveness for correction of vaglus knee with osteoarthritis.

[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.