Closed versus open kinematic chain measurements of subtalar joint eversion: implications for clinical practice.

Subtalar joint (STJ) range of motion is most critical during the support phase of the gait cycle. The purpose of this study was to determine what differences exist between measures of maximal STJ eversion in open chain and closed chain positions. STJ eversion as a component of STJ pronation was measured in nonweightbearing (NWB) and full weightbearing (WB) positions on 17 subjects who had no significant biomechanical or orthopaedic abnormality. STJ WB eversion was significantly greater than NWB passive ROM. These results indicate that accurate assessment of STJ eversion as a component of pronation requires measurement in a functional WB position as well as in a NWB position. Rehabilitation of persons with lower quarter injuries or disabilities require assessment of ROM in WB positions so that a more accurate and complete evaluation can be done allowing the clinician to make an appropriate diagnosis and treatment.