RESEARCH REPORT PLATFORM PRESENTATION

RELIABILITY AND VALIDITY FOR TEST BATTERIES FOR MAXIMAL SINGLE-LEG HOP PERFORMANCE AND MUSCLE POWER IN PATIENTS WITH ACL INJURY. Neeter C¹, Gustavsson A, Thomeé R, Grävare Silbernagel K, Augustsson J, Karlsson J; ¹Dept of Orthopaedics, Lundberg Laboratory, Göteborg University

PURPOSE: The purpose was to develop test batteries with high ability to discriminate performance between the injured and the uninjured side in patients with anterior cruciate ligament (ACL) injury. RELEVANCE: The literature clerly points out that there is a need for reliable, valid and sensitive instruments to evaluate muscle functionto in order to determine when it is safe to return to strenuous physical activities. PARTICIPANTS: For the single-leg hop test battery 15 healthy subjects performed five hop tests at three separate occasions in a test-retest design on each leg (n = 30). Thereafter 30 patients with ACL injury were tested 6 months after injury and 35 patients were tested 12 months after ACL reconstruction. For the muscle power strength test battery 13 healthy subjects were tested in a test-retest design on each leg (n = 26). Twenty-three patients with an ACL injury were tested 6 months after injury and 44 patients were tested 6 months after ACL reconstruction. METHODS: Five hop tests were analysed and the three tests with the highest ability to discriminate hop performance between the injured and uninjured side were chosen for the test battery: the counter movement jump, the hop for distance and the side hop test. Three tests were chosen for the strength test battery to reflect quadriceps and hamstrings muscle power in a knee extension and a knee flexion test (open chain) and lower extremity muscle power in a leg press test (closed chain). ANALYSIS: Conventional methods were used for descriptive statistics and correlations. Non parametric methods were used for group comparisons. Significance was considered at p < 0.05. Test-retest analysis was determined by intraclass correlation coefficient (ICC). A methodological error in percent was calculated. Lower limb symmetry index (LSI) was calculated to determine whether a side-to-side leg difference was classified as normal or abnormal. In this study LSI greater than or equal to 90% was classified as normal. RESULTS: No significant differences were found between test occasions in any of the three strength tests or the three hop tests. The ICC ranged from 0.87 to 0.98 and the methodological error from 3 to 10%, for the strength and hop tests. The sensitivity for the hop test battery was 87% in the patients with ACL injury and 91% in the patients after ACL reconstruction. The three strength tests combined into one test battery gave a sensitivity of 60% for the patients 6 months after ACL injury and 94% for the patients 6 months after ACL reconstruction. CONCLUSIONS: The principal finding of this study was that a test batteries had high ability in terms of discriminating hop as well as strength performance between the injured and the uninjured side, both in patients with ACL injury and in patients after ACL reconstruction. It is concluded that the test batteries showed high test-retest reliability and a higher sensitivity than any of the tests individually. IMPLICATIONS: The test battery may contribute to the decision-making process of deciding whether patients can return safely to strenuous physical activities after ACL injury or reconstruction. KEYWORDS: power, hop, test battery. FUNDING ACKNOWLEDGEMENTS: This study was supported by a grant from the Swedish Centre for Research in Sports and The Local Research and Development Council for Gothenburg and Southern Bohuslän, Sweden. CONTACT: camille.neeter@orthop.gu.se

ETHICS COMMITTEE: Approval for the study was obtained from the Human Ethics Committee at Göteborg University, Sweden.