Cannot do one foot heel raise but no other symptoms of posterior tibial tendon dysfunction

I fractured my foot at the midfoot 4 months ago. Have been going to PT because was in a cast for 10 weeks. I cannot do a one foot heel raise on the injured foot which I could do before the fracture. Is it possible the muscles are just weak or is the inability to do this heel raise always a symptom of something wrong with the posterior tibial tendon? I do not have extreme pain anywhere in the foot although it seems slightly swollen just above the arch at the midfoot and does ache there occasionally.