Intra- and intertester reliability and criterion validity of the parallelogram and universal goniometers for measuring maximum active knee flexion and extension of patients with knee restrictions

Objective: To examine the intra- and intertester reliability of the univers al goniometer (UG) and parallelogram goniometer (PG), and to assess the cri terion validity of the same instruments on subjects with knee restrictions. Design: Reliability and validation study. Setting: Radiology department at university hospital. Participants: Sixty subjects (34 men, 26 women; mean age, 52yr) with variou s knee restrictions. Interventions: Sixteen goniometric measurements were collected per patient by 2 physical therapists. Subjects were evaluated in knee flexion and knee extension positions. To serve as a gold standard, radiographs were taken in both positions. Main Outcome Measures: Active knee flexion and knee extension on 2 goniomet ers, radiographs. Maximum active range of motion (AROM). Results: The UG intratester reliability (intraclass correlation coefficient s [ICCs]) was .997 in flexion and .972 to .985 in extension. The results we re also high with the PG (ICC = .996,.953-.955) for flexion and extension, respectively. The intertester reliability was high for flexion (ICC = .977- .982) and for extension (ICC = .893-.926) when using the UG. For the PG, IC C results ranged from .959 to .970 for flexion and from .856 to,898 for ext ension. Criterion validity (r) varied from .975 to .987 for flexion and fro m .390 to .442 for extension with the UG, and from .976 to .985 for flexion and .423 to .514 for extension with the PG. Conclusion: Intra- and intertester reliability were high for both goniomete rs, The results for the criterion validity varied. Our study also revealed that it is preferable to use goniometry rather than Visual estimations when measuring AROM. It is recommended that the same therapist take all the mea surements when assessing AROM for UG and PG goniometric measurements on pat ients with knee restrictions.