Introduction: This paper reports leg alignment and knee surface measurements taken from 100 young adult limbs using actual physical bone measurements (APB).

Method: The specimens were part of the Spitalfields Collection of 1000 skeletons held in the Natural History Museum, London. Selection criteria included full life documentation, absence of degenerative change and perfect preservation. There were 28 females (45 knees) and 29 males (55 knees). Mean age was 40 years. The femora and tibiae were accurately articulated with the knee extended. Digital images were obtained in neutral, 15 degrees internal rotation and 15 degrees external rotation.

Results: Mean axial alignment of both sexes was valgus (female> male). Using the 2 tailed t-test valgus alignment differed significantly from neutral alignment (p< 0.001) in this population. Internal rotation exaggerated an alignment into valgus and external rotation exaggerated an alignment into varus. The knee joint inclination of both sexes was valgus with respect to the mechanical axis of the tibia (female> male). The physiological valgus angle of the knee more closely resembled the accepted value of 6 degrees in the female.

Discussion: This is the first report of APB measurements as opposed to x-ray analysis in a normal population. It is clear that considerable individual variation occurs in all parameters. Development is likely to be affected by genetic, cultural and occupational factors. Measurements are also affected by limb rotation. We believe that arthroplasty techniques may be more successful if alignment is planned to the individual.