The design of external fixators for the repair of fractures of the hand is mandated by the need for simplicity of reduction that respects the anatomy adjacent to the bone. Although less invasive, Kirschner wires do not always provide sufficient stability to permit early mobilization and hence functional rehabilitation. In addition, the surgeon has to work in limited areas making sure to preserve the hand’s anatomical balance.

Materials and Methods

Since the 1980s our Orthopedic Division and subsequently our Hand Surgery and Microsurgery Unit have employed external fixation systems to manage traumas of the hand. The system most frequently used is the SEM (the Modular External Stabilizer), designed specifically for the hand and employing both trans-skeletal threaded pins or simple K-wires. As a result, the SEM system can be used as means of reduction and fixation or as a stabilizer after minimal fixation with K-wires, in both cases allowing early joint mobilization.

The modular system also enables skeletal lengthening procedures even in segments less than 2cm long. The system was formerly constrained by the excessive mobility of the clamp and threaded rod assembly, which given the very small size of the clamps, proved difficult for surgeons to manipulate easily. Surgical outcomes reported in the literature were, however, always positive.

The system has recently been revised becoming more user- friendly while keeping all the distinctive features of the SEM system. In particular, the clamps are still designed to hold both trans- skeletal self-threading pins or simple K-wires of either equal or different size. In addition, compression and distraction can be obtained simply by engaging the threaded rod or creating an arc linking the threaded rods to form a bridging or delta frame, a technique used both in lengthening procedures as well as to maintain alignment in cases of massive bone loss.

The SEM II has been employed to manage all kinds of phalangeal and metacarpal fractures and allows early mobilization. Fracture and osteotomy-site healing have always been achieved.

Results

Average consolidation time is 4 weeks for metacarpal fractures, 6 weeks for phalangeal fractures and 3 months for lengthening procedures up to 2 cm. Patients without complex trauma resume their daily activities within 48 hours of surgery.

Conclusions

External fixation systems are a valid solution in the management of hand fractures. The possibility of using self-tapping pins or simple K-wires is key to maintaining the structural anatomy and allowing early mobilization and so early rehabilitation. In conclusion, we underline the importance of SEM II in the management of corrective osteotomies since the system allows progressive post- operative realignment over time.

References

Mele R. Stabilizzatore esterno modulare SEM” Riv. Chir Mano, 25(3): 431-442, 1988 Mele R., Vivaldi R. Allungamento dei monconi delle dita lunghe. Riv. Chir. Mano, 29(1-2): 139-142,1992
Ghiggio P., Nobile G. L’utilizzo dello stabilizzatore esterno modulare SEM nelle patologie traumatiche della mano, 26(2-3): 152-155,1989 Guerini R.,Budassi P.La fissazione esterna nelle patologie traumatiche della mano, 30(2): 195-203, 1993