Proximal tibiofibular joint (PTFJ) dislocation due to Ehlers-Danlos syndrome: posterolateral open-wedge high tibial osteotomy combined with medial closed-wedge distal femoral osteotomy can correct the severe valgus deformity with a markedly increased tibial posterior slope.

Ehlers-Danlos syndrome (EDS) causes joint hypermobility and joint dislocation. Since there are no reports of proximal tibiofibular joint (PTFJ) dislocation caused by EDS, little is known about the long-term course of this disease. A woman in her 40s presented with a posterolaterally depressed tibial condyle and severe valgus deformity caused by a long-standing PTFJ dislocation due to EDS. Considering the pathology, posterolateral open-wedge high tibial osteotomy (PLOWHTO) and medial closed-wedge distal femoral osteotomy were performed according to the deformity analysis. A favourable short-term clinical outcome was obtained and the PTFJ dislocation was reduced over time. Although PLOWHTO has several pitfalls, it is a logical and useful surgical technique that can help treat posterolateral dysplasia of the tibial plateau concomitant with severe valgus deformity, regardless of joint laxity, if performed with attention to pitfalls.