Benefit of Adding Fibular Osteotomy to Open-Wedge, Valgus, Distal Tibial Osteotomy for Correcting Varus Ankle Arthritis: An In Vitro Study

Abstract

Early-stage varus ankle arthritis can usually be treated with a medial, open-wedge, valgus, distal tibial osteotomy; however, the value of adding a fibular osteotomy has been debated. We sought to determine the increase in the maximum medial osteotomy gap and correction angle provided by fibular osteotomy. In 3 sequential experiments on 12 fresh cadaveric legs, we first performed a medial open-wedge, valgus, distal tibial osteotomy alone. Second, we added a transverse fibular osteotomy. Finally, we added a blocked fibular osteotomy. In each experiment, we measured the maximum corrected osteotomy gap and the maximum correction angle. Correction was defined as the absence of lateral cortex diastasis and talocrural joint incongruity. The mean ± standard deviation maximum osteotomy gaps and correction angles were 8.40 ± 1.6 mm and 10.70° ± 3.3° for the tibial osteotomy alone, 15.70 ± 4.6 mm and 20.20° ± 5.6° for the tibial plus transverse fibular osteotomy, and 16.67 ± 3.7 mm and 20.56° ± 4.6° for the tibial plus transverse plus blocked fibular osteotomies, respectively. The corresponding median maximum correction angles were 10° (range 8° to 18°), 19.5° (range 14° to 30°), and 20° (range 14° to 28°). The osteotomy gap and correction angle in the distal tibial and transverse fibular osteotomy were significantly greater than those in the distal tibial osteotomy alone (p < .001 for both) but not in the distal tibial and blocked fibular osteotomy (p = .62 for the gap and p = .88 for the correction angle). Our data support the clinical use of adjunct transverse fibular osteotomies. The blocked fibular osteotomy provided no additional benefit.