Does muscle improve validated outcome measures in open tibial fractures? New insights from a cohort study of the anterolateral thigh flap (ALT) versus ALT-Vastus lateralis flaps

The benefits of the muscle in open lower limb fractures remain to be determined. This study compared statistically equivalent groups of open tibial fractures treated by free anterolateral thigh (ALT) flaps or ALT flaps incorporating muscle (ALT-Vastus lateralis/ALT- VL). Method and Results: Chang Gung Memorial Hospital, Taiwan, 2004–2008, 49 free flaps in open lower limb fractures (38 open tibial) were specifically reconstructed with free ALT or ALT-VL flaps. Risk factors for non-union: equivalent between the two groups, with no differences in smoking, steroids, diabetes, time to flap and the AO classification of soft tissue and bone injury. Comparison of union rates: no difference was noted between groups in the Radiographic Union Score in Tibial Fractures (RUST) at 3, 6, 9 and 12 months. The only factor significantly associated with non-union was presence of a SPRINT trial defined ‘critical’ bone defect with odds ratio 14.4 (95% CI 1.36 - 131.5), with no association with AO bone classification, flap type, comorbidity or flap size. Patient-reported outcomes: the ALT-VL group showed improved patient satisfaction (p = 0.01, Cohen's d = 1.1). Functional outcomes (Enneking score) were not statistically significant, but the ALT-VL group trended towards significance in function and skin quality domains. Conclusions: Based on the results of this study, one can conclude that the degree of bone injury (specifically a ‘critical’ defect) is of greater relevance than flap choice with regard to fracture consolidation. Muscle does not result in improvements to union, the speed of union or deep infection. However, better PROMs may be related to the inclusion of the muscle around the fracture site.