Sentence:  Since a Skeletal Age rating can be made at any age during growth , from Elbow , Shoulder , <WSD>Knee</WSD> , or Foot as well as Hand , it seems to be the method of choice when one wishes to study most aspects of skeletal developmental progress during childhood . 
Meaning of the word marked with <WSD> tags:  hinge joint in the human leg connecting the tibia and fibula with the femur and protected in front by the patella