THE ROLE OF EXCHANGE INTRAMEDULLARY NAILING IN INFECTED TIBIAL NON-UNION

Abstract

Aim: The purpose of this study was to investigate the validity of exchange intramedullary nailing for the treatment of infected tibial non-union.

Patients and Methods: Between 1994 and 2001 14 (10 male) patients with tibial fractures were treated in our institution with exchange nailing for infected tibial non-union. The mean age of the patients was 34.3 years (range 18–60) and the mean ISS was 17.5 (range 9–57). Road traffic accidents was the causative mechanism in 10 cases. Seven fractures were originally open (grade IIIb). Initial stabilisation was with intramedullary nailing in 7 cases, external fixator in 3, open reduction internal fixation in 2, Ilizarov frame in 1 and POP in 1. All patients had clinical and radiological evidence of non-union and in each case there was clinical and microbiological evidence of intramedullary infection. All the patients subsequently had an exchange intramedullary nail performed together with debridement and antibiotics. The mean time between original nailing and exchange nailing was 28 weeks. At exchange nailing, the old incisions were reopened and the in situ nail was then removed. Following this, the canal was swabbed and then reamed 1½ mm. more than the diameter of the new nail. The swab and reamings were sent for culture and microscopy. The canal was also irrigated with at least 3 litres of normal saline prior to the insertion of the exchange nail. Antibiotics were then continued for a minimal period of 6 weeks, or longer as the clinical situation warranted. Following discharge from the hospital the patients were seen in the outpatient clinics with regular clinical, haematological and radiographic investigations. The average length of follow-up was 24 months following exchange nailing.

Results: There were 7 positive cultures of MRSA, 4 of staph. aureus and in 3 cases multiple bacteria were grown from the samples. No further treatment was required following exchange nailing in 5 (35.7%) cases out of 14. 4 patients required further soft tissue debridement and a free flap to secure union within a week of the exchange nailing procedure. Of the remaining 5 patients, 1 required dynamisation to encourage union; another required incision and drainage of peri-fracture abscess and proceeded to union uneventfully; the third patient needed iliac crest bone grafting which eventually resulted in union. The penultimate patient had numerous operations after the exchange nailing before finally uniting with bone morphogenic protein. Unfortunately the last patient developed overwhelming sepsis which necessitated below knee amputation. Overall, the mean time to union was 11.3 months (4–24).

Conclusion: In this series of patients the success rate of exchange nailing for septic tibial pseudarthrosis was 78.5% (11/14). However, some of the patients, especially those originally sustaining open fractures required additional procedures to secure union. We believe that exchange tibial nailing remains an effective method of treatment in the presence of deep bone sepsis.