Tibia deformity correction by circular external fixator in multiple enchondromatosis

Abstract

Objective To discuss the outcomes of tibia varum and shorting deformity correction by circular external fixator in multiple enchondromatosis. Methods Thirty-one tibias treated with varum and shorting deformity correction by circular external fixator in multiple enchondromatosis were statistically analyzed. Of 31 tibias (28 cases), 12 were from boys, and 19 from girls, with an average age of 12.3 years. After open tibia and fibula osteotomy through small incision, all tibia varum and shorting deformity were corrected slowly by circular external fixator. The patients were followed up for 1, 2, 3, 6, 12, 24 and 36 months after the operation. Preoperative and postoperative data at 12th and 36th month about tibia shorting deformity, angle of varus knee, medial proximal tibial angle, lateral distal tibial angle, the maximum length and width of the tumors which had been gone through by stainless steel needles were analyzed. Results As compared with the preoperative group whose tibia shorting deformity was (35.16±8.62) mm, postoperative tibia shorting deformity at 12th and 36th month was (16.04±2.73) mm and (6.99±1.93) mm respectively, the difference between the two groups had statistical significance (t=15.927, P=0.000; t=20.814, P=0.000). As compared with the preoperative group whose angle of varus knee was (25.0±7.9)°, postoperative angle of varus knee at 12th and 36th month was (2.1±0.9)° and (5.0±1.1)° respectively, the difference between the two groups had statistical significance (t=15.955, P=0.000; t=13.843, P=0.000). As compared with the preoperative group whose medial proximal tibial angle was (70.6±3.0)°, postoperative medial proximal tibial angle at 12th and 36 month was (88.7±1.6)° and (87.6±1.4)° respectively, the difference between the two groups had statistical significance (t=-26.806, P=0.000; t=-28.591, P=0.000). As compared with the preoperative group whose lateral distal tibial angle was (131.5±2.9)°, postoperative lateral distal tibial angle at 12th and 36th month was (88.9±1.9)° and (89.3±1.8)° respectively, the difference between the two groups had statistical significance (t=78.459, P=0.000; t=71.467, P=0.000). As compared with the preoperative group whose the maximum length of the tumors was (46.2±23.7) mm, postoperative maximum length of the tumors at 12th and 36th month was (47.2±24.0) mm and (46.6±24.1) mm respectively, the difference between the two groups had no statistical significance (t=-1.808, P=0.081; t=-0.741, P=0.464). As compared with the preoperative group whose maximum width of the tumors was (33.9±5.0) mm, postoperative the maximum width of the tumors at 12th and 36th month was (34.6±6.3) mm and (35.1±5.1) mm respectively, the difference between the two groups had no statistical significance (t=-1.014, P=0.319; t=-1.910, P=0.066). All patients were not diagnosed with osteomyelitis and had no symptoms of nerve and vascular injury. Conclusion It demonstrates that tibia deformity correction by circular external fixator in multiple enchondromatosis is safe and effective. Tumors being gone through by stainless steel needles have no growth rapidly in a short time. But the higher probability of malignant change is necessitating lifelong follow-up. Key words: Multiple enchondromatosis; Tibia; Circular external fixator