Vascularized fibular graft in infected tibial bone loss

Abstract

Background:The treatment options of bone loss with infections include bone transport with external fixators, vascularized bone grafts, non-vascularized autogenous grafts and vascularized allografts. The research hypothesis was that the graft length and intact ipsilateral fibula influenced hypertrophy and stress fracture. We retrospectively studied the graft hypertrophy in 15 patients, in whom vascularized fibular graft was done for post-traumatic tibial defects with infection.Materials and Methods:15 male patients with mean age 33.7 years (range 18 - 56 years) of post traumatic tibial bone loss were analysed. The mean bony defect was 14.5 cm (range 6.5 – 20 cm). The mean length of the graft was 16.7 cm (range 11.5 – 21 cm). The osteoseptocutaneous flap (bone flap with attached overlying skin flap) from the contralateral side was used in all patients except one. The graft was fixed to the recipient bone at both ends by one or two AO cortical screws, supplemented by a monolateral external fixator. A standard postoperative protocol was followed in all patients. The hypertrophy percentage of the vascularized fibular graft was calculated by a modification of the formula described by El-Gammal. The followup period averaged 46.5 months (range 24 – 164 months). The Pearson correlation coefficient (r) was worked out, to find the relationship between graft length and hypertrophy. The t-test was performed to find out if there was any significant difference in the graft length of those who had a stress fracture and those who did not and to find out whether there was any significant difference in hypertrophy with and without ipsilateral fibula union. The Chi square test was performed to identify whether there was any association between the stress fracture and the fibula union. Given the small sample size we have not used any statistical analysis to determine the relation between the percentage of the graft hypertrophy and stress fracture.Results:Graft union occurred in all patients in a mean time of 3.3 months, at both ends. At a minimum followup of 24 months the mean hypertrophy noted was 63.6% (30 – 136%) in the vascularized fibular graft. Ten stress fractures occurred in seven patients. The mean duration of the occurrence of a stress fracture in the graft was 11.1 months (2.5 – 18 months) postoperatively. The highest incidence of stress fractures was when the graft hypertrophy was less than 20%. The incidence of stress fractures reduced significantly after the graft hypertrophy exceeded 20%.Conclusion:In most cases hypertrophy of the vascularized fibular graft occurs in response to mechanical loading by protected weight bearing, and the amount of hypertrophy is variable. The presence or absence of an intact fibula has no bearing on the hypertrophy or incidence of stress fracture. The length of the fibular graft has no bearing on the hypertrophy or stress fracture.

Length of Vascularized Fibula Graft Utilized and Union: Is There a Relationship?

“…9 Furthermore, the length of the graft has not been found to correlate with other parameters of graft incorporation or healing such as graft hypertrophy. 10,11 Increasing graft length has been associated with increased rates of graft fracture, 3 although no cases of fracture were seen in the present study. Increased graft length does not seem to result in lower union rates but may increase risk of complication.…”

“…Other series have reported union rates ranging from 41 to 100%. [3][4][5][6]9,[11][12][13][14][15][16] Our results are in the middle of previously reported rates. In all but one patient, primary union occurred at least at one end of the graft, suggesting that when a nonunion occurs it is likely to be only at one of the junctions and not both.…”

Infected nonunion of tibia

“…Infection and anastomotic failure could result in significant morbidity. Combining the free vascularized fibula with the Ilizarov fixator combines benefits of both methods to fill up gaps in infected nonunions 4243…”

“…Bone transport technique 3 4 5 6 7 8 with its variations of technique and hardware is the established method. The alternative is to use the induced membrane technique described by Masquelet et al ., 37 38 39 40 41 and fill up the gap with the help of vascularized bone grafts 42 43 and/or substitutes. 44 45 …”

Strategies for large bone defect reconstruction after trauma, infections or tumour excision: a comprehensive review of the literature

“…A classical single vascularized fibular graft (Fig. 1 ), having a reduced cross section, could be at risk of stress fractures if used in the lower limbs [ 34 , 38 , 39 ]. To prevent them, techniques such as the double-barrel technique and the combined vascularized fibula and allograft reconstruction have been developed [ 38 ].…”