In 1785, Lee injured a knee on an expedition for Washington. Three years later, while he went to the post office in Alexandria, he fell and injured his other knee, which rendered him seriously disabled. After Washington was elected president in 1789, Lee attempted to make the journey to New York City for Washington's first inauguration but had to be left in Philadelphia for medical treatment. He was attended by several physicians, who made a steel brace for his knee, which allowed him to join Washington's presidential household. Frank's nephew, Christopher Sheels, assisted Lee in New York City and took over Lee's duties in 1790 at the Philadelphia President's House.