Function and development of the elbow after the transphyseal fracture of the distal humerus in infants

ZHOU Wei-Zheng; ZHANG Li-Jun; LI Lian-Yong

doi:10.3969/j.issn.2095-252X.2017.07.002

Abstract：Objective To evaluate the function and development of the elbow after the transphyseal fracture of the distal humerus in infants. Methods From January 2005 to February 2015, institutional records of 16 patients ( 16 elbows ) were reviewed retrospectively. These patients were treated in the authors' institution for the transphyseal fracture of the distal humerus. All the patients were injured by fall from a bed or bicycle. The average age of the patients was 18 months ( range: 11 - 37 months ); 10 of the cases were boys ( 10 elbows ), and 6 were girls ( 6 elbows );the fracture involved the left elbow in 9 patients ( 56.3% ) and the right elbow in 7 ( 43.7% ). According to the Salter-Harris classification, three ( 18.8% ) lesions were type Ⅰ, and the others were type Ⅱ. As for the displacement of the distal fragment, 14 of the 16 lesions ( 87.5% ) were moved posteromedially, and the rest two ( 12.5% ) were posterolaterally; secondary ossification center of capitellum was non-ossifying in 6 elbows. Five ( 31.3% ) patients underwent open reduction and percutaneous pinning, and the other 11 ( 68.7% ) patients were treated with closed reduction and percutaneous pinning. One closed reduction was performed under the assistance of arthrogram. The anteroposterior ( AP ) and lateral radiography of the double elbows and the whole-length anteroposterior ( AP ) radiography of the double humerus were taken at follow-up, the humeral-ulnar angle, the humeral shaft-condylar angle and the humeral length were measured and compared between the injured elbow and the normal. The Mayo Elbow Performance Score ( MEPS ) was used to evaluate the functional outcomes of the elbow. Results All the 16 patients were followed up for an average of 42.3 months ( range: 6 - 98 months ). For the range of elbow motion, the maximal extension was in average 5.9 degrees on the injured elbow, and 7.5 degrees on the normal ( P = 0.33 ). The maximal flexion was in average 124.4 degrees on the injured elbow, and 133.1 degrees on the normal ( P = 0.01 ). The humeral shaft-condylar angle on the affected elbow was in average 47.1 degrees ( range: 25 - 59 degrees ) , and that was 51.9 degrees ( range: 35 - 65 degrees ) on the normal side, P = 0.073. The average humeral-ulnar angle was 1.2 degrees ( range: -18 - 14 degrees ) on the injured elbow, and 8.8 degrees ( range: 2 - 19 degrees ) on the normal side, P = 0.001. The average humeral length was 20.7 cm ( range: 16.0 - 26.3 cm ) on the injured size, and 20.3 cm ( range: 15.5 -25.8 cm ) on the normal size, P < 0.001. The MEPS was in average 85.6 points ( range: 70 - 95 points ) on the involved side, and 95 points ( range: 90 - 100 points ) on the uninvolved side, P < 0.001. There were no statistical differences in the humeral-ulnar angle ( P = 0.57, 0.23 ) when compared the reduction procedures and the Salter-Harris classification. MEPS was not related to the displacement ( P = 1.00 ), Salter-Harris classification ( P = 0.35 ) and reduction procedures ( P = 1.00 ) and ossifying of capitellum secondary ossification center ( P = 0.93 ). Conclusions For the transphyseal fracture of the distal humerus in infants, an excellent functional outcome is expected when treated with closed or open reduction and percutaneous pinning. However, it should be kept in mind that residual cubitus varus is a frequently seen complication. Further investigations should focus on whether the intraoperative arthrogram is helpful to avoid cubitus varus.