Groove deepening for intrasheath peroneal tendon subluxation. A, Detachment of superior peroneal retinaculum. B, Osteotomy of posterior fibula. C, Elevation of posterior fibular bone for groove deepening. D, Removal of cancellous bone with burr. E, Bone tamp used to impact bone flap into deepened groove. F and G, Separation of superior peroneal retinaculum into two segments to place superior limb between subluxating peroneal tendons. H, Holes drilled into lateral fibula for attachment of retinaculum. I, Superior limb of retinaculum passed deep to peroneus longus, inferior limb passed over peroneus longus. J, Completed repair.