[A comparative study on two different absorbable intramedullary nails in treating metacarpal and phalanx fractures]

To study the effect of two different absorbable intramedullary nails in treatment of metacarpal and phalanx fractures.

From January 2002 to December 2002, open reduction and internal fixation were done with two different absorbable intramedullary nails in 60 cases of metacarpal and phalanx fractures (52 cases of open fractures and 8 cases of closed fractures). The fracture locations were metacarpal in 24 cases, proximal phalanx in 22 cases and media phalanx in 14 cases. The emergency operation was performed in 47 cases, selective operation in 13 cases. Out of 60 patients, 24 were treated with intramedullary nails of poly-DL-lactic acid (PDLLA) (PDLLA group), 36 with intramedullary wire of PDLLA composed of chitosan(PDLLA+chitosan group).

In the PDLLA group(n = 24), the rejection occurred in 8 cases 3-4 weeks after operation. PDLLA nails were taken out in 6 of the 8 cases after 5-10 days of operation and bone healing was achieved 2 months after re-fixation by Kirschner wire; the rejection subsided in the other 2 cases after 25 days of conservative treatment, and bone fracture healed after 14 weeks. No rejection was observed with primary healing in the other 16 cases of the PDLLA group. In PDLLA + chitosan group(n = 36), the rejection occurred in 1 case 19 days after operation, but the rejection subsided after 3 days of conservative treatment. No rejection was observed in the other 35 cases with primary healing. All patients were followed up 4-11 months with an average of 6 months. No rejection was observed and bone healing was achieved during the follow-up. The time of bone healing was 6-16 weeks (8 weeks on average). There was statistically significant difference in the curative result between two groups(P < 0. 05). Conclusion Intramedullary nail of PDLLA was very suitable to fix fractures of metacarpal and phalanx. During the degradation of PDLLA, the acidic products can cause rejection. When PDLLA mixed with chitosan, PDLLA can not only strengthen the intensity but also neutralize the acidity. So the rejection can be decreased. PDLLA intramedullary nails composed of chitosan were better than PDLLA intramedullary nails in clinical treatment of metacarpal and phalanx fractures.