Most of the fractures of thumb metacarpals can be treated successfully nonoperative, but a less subset, especially severely displaced RW-C requires aggressive procedures. The rupture of the periosteum makes the distal fragment unstable and immobilization with the first ray unreliable . Studies on this topic are rare. The management of obviously displaced RW-C thumb metacarpal base fractures in children still is a challenge for pediatric orthopedics. Closed reduction is more difficult for severely angulation and displaced RW-C fractures.
According to some authors, RW-C fractures under 30% angulation disbalance can be treated by closed reduction and splinting. We synthesized the results of Kulus SC  and Kuntscher  Anteroposterior and lateral X-ray films and three-dimensional computerized tomography(3DCT) of the injured hand were taken for each child. the maximum angle of fracture was > 40 degrees, displacement of fracture > 2/3, or children with rotational deformity were conducted with aggressive procedures. All 17 cases were in accordance with these operative indications.
The mobility of the metacarpal base and the swelling make closed reduction difficult. Comminution, soft tissue interposition, or transperiosteal “buttonholing” may further complicate reduction [5, 11]. The aim of treatment of these fractures is to obtain anatomic reduction. An unsuccessful closed reduction requires open reduction and fixation . For the RW-C fractures, the distal part fragment of fracture moves toward the second metacarpal and hides into thenar. Manual closed reduction of RW-C fracture needs axial traction on the thumb and pressure is placed on the base of the distal fragment . Both of the second metacarpal and thenar hider impact the manual closed reduction. In our theory, these are the true reasons for the failure of closed reduction. Our leverage technique described in this study proved minimal invasive and reliable to avoid open reduction.
Although some studies reported severely displaced RW-C fractures might require open reduction to remove any interposed periosteum that blocked reduction. Open reduction is indicated for irreducible RW-C fractures [10, 13]. Jehanno et al reported open reduction is not due to interposition of tendons or of the periosteum . In general, manual reduction and leverage treatment of pediatric fractures are successful in most cases with good results, including S-H type Ⅱ fractures of the distal radius, radial neck fracture, supracondylar fracture, Bennett fracture, and satisfactory results have been achieved [14–17]. We conduct leverage reduction to obtain anatomical reduction of these fractures. The attempt times of leverage manual reduction can be reduced to less than 3, meanwhile the injury of physis caused by the tip of leverage k-wire can be avoided. There was no physis premature closure, bone bridge formation and epiphyseal ischemic necrosis in our cases.
There are many options for pin configuration including pinning across the reduced carpometacarpal (CMC) joint, Iselin technique, modified Iselin technique, and direct fixation across the fracture [7, 10, 13, 18, 19, 20]. Some authors recommend that intraarticular k-wires may aggravate articular surface lesion which will cause post-traumatic arthritis. This is why the Iselin method was proposed . Some researchers reported the incidence of secondary displacement because of faulty Iselin technical approach and the loss of the maintaining the quality of reduction . Wiggins preferred the technique that a transfixing k-wire across the epiphyseal growth plate, which has never been reported to cause epiphysiodesis . Hastings also reported the thumb base fracture fixation with the longitudinal K-wires fixation with good results . We prefer DACK-wires fixation, which has been proved to be good technique in previously studies. Bone union was achieved in all 16 patients within a mean time of 4.2 (range4 ~ 6 weeks). The clinical results were 15 excellent results and one good result, without secondary displacement of the fracture, tendinous adhesion. In our experience, the advantages of DACK-wires fixation include easy selection of needle puncturing point, stable transfixing K-wires across the epiphyseal growth plate which is more stable than Iselin technique.
In our research, most of the duration time of leverage procedures were performed within 0.29 min by 1–3 attempts of attempts. Longer duration time of leverage procedure are associated with more radiation exposure (RE). The risk of RE need to be understood and minimized in pediatric trauma theatres, which is associated with malignant diseases . Ultrasonography (US) has also been used for intraoperative monitor for the treatment of radial neck fractures in children to reduce the dose of RE . The US could be courageous alternative of X-ray in the near future for this kind of fractures during the intraoperative intensifier.
Our experience shows that the following key points should be mastered in the procedures: (1) According to preoperative imaging data and C-arm image intensifier, the plane with the largest displacement and angulation of fractures should be judged as the leverage plane, so as to achieve anatomical reduction and reduce times of leverage. (2) adjacency of abductor pollicis longus tendon and the first metacarpal epiphysis are tagged as the puncturing points of wires to reduce the tendinous adhesion. (3) DACK-wires fixation is reliable; (4) When leveraging, the tip of the K-wire should be moved toward the metaphyseal to prevent the injury of physis; (5) Different from other metacarpals, AP and lateral X ray of the thumb metacarpal were available, which can show angulation and displacement more reliable.
The main limit of this study was that it is a retrospective cohort with a small size, without control group. We cannot confirm that our technique is superior than others. However, our series dose obtain satisfactory outcomes with less complains. Further studies with a large cohort would be needed.