| Objective:To investigate the exposed articular surface area of the distal humerus by the combined medial-lateral approach,the finite element analysis of the novel double plates internal fixation and the clinical effects of the combined medial-lateral approach of the elbow joint with double plates internal fixation in the treatment of type C fracture of the distal humerus.Methods:Twelve frozen elbow joints were randomly divided into two groups:the combined medial-lateral approach group(group A)and the olecranon osteotomy approach group(group B),which were used to perform autopsy to expose the distal humeral articular surface,and the exposed area was measured and calculated.The traditional vertical double-plates model(group C)and the novel anteromedial and anterolateral double-plates model(group D)used to establish the type C1 fracture of the distal humerus were modeled by specific software to simulate various tests of biomechanics for finite element analysis.From May 2015 to March 2017,47 eligible patients with type C distal humeral fractures were enrolled into two groups:the combined medial-lateral approach group(group E,32 cases)and the olecranon olecranon approach group(group F,15 cases),through the MEPS and DASH scores to assess the clinical effects of patients with postoperative recovery.Results:The exposed area of the medial incision in group A was 6.8 cm~2,the lateral incision was 6.7 cm~2,and the medial-lateral incision was 9.2 cm~2,accounting for 46.9%of the total articular surface.The posterior incision of group B can expose an area of13.7 cm~2,accounting for 63.1%of the total articular surface.The exposed area of group B was better than group A(P=0.001).Compared with the group C,the group D has a more uniform force distribution,a smaller maximum displacement,a greater stiffness in each working condition,and a stronger deformation resistance.The flexion-extension motion of elbow joint in group E was 112.3°±16.1°,and that in group F was110.7°±17.2°.The difference was not statistically significant(P=0.746).The pronation–supination of the forearm in group E was 160.8°±7.4°,and that in group F was 154.7°±9.3°.The difference was statistically significant(P=0.020).The pronation–supination of the forearm was better in patients with the combined medial-lateral group than the olecranon osteotomy group.There was a significant difference in the postoperative complication rate between the two groups(P=0.037).The postoperative complication rate of the patients with the combined medial-lateral approach group was significantly lower than the olecranon osteotomy group.There was no significant difference in the mean MEPS,DASH and excellent rate between the two groups(P=0.840,P=0.502,P=0.923).Conclusions:The combined medial-lateral approach can expose nearly half of the distal humeral articular surface,mainly focused on the anterior portion,and the internal fixation of the novel double-plates can provide great stiffness and resistance to deformation.The clinical effects of the combined medial-lateral approach with double plates internal fixation in the treatment of type C fracture of the distal humerus is good.Compared with the olecranon osteotomy,the hospital stay is shorter,the intraoperative blood loss is smaller,the complications are less,and the pronation–supination of the forearm is better.Therefore,for the treatment of type C fracture of the distal humerus,the combined medial-lateral approach with double plates internal fixation is a successful surgical approach. |
