Reliability testing of a new device to measure tibial rotation

Abstract

The purpose of this study was to evaluate the reliability of a new developed device to measure tibial rotation, the Rotameter. Thirty healthy subjects (15 males, 15 females, 24 years) were examined with the Rotameter measurement device. External and internal rotation was performed at an applied torque of 5, 10 and 15 Nm by two independent examiners in order to test the inter-observer reliability. The patients were measured again after a mean of 31 +/- 43 days by the same examiners to test the intra-observer reliability. Statistical analysis was performed using the intra-class correlation coefficient. The Pearson Correlation coefficient was used to compare the measurements of the left with the right side of the participants. In the measurements, a high inter- and intra-observer reliability was found at 5, 10 and 15 Nm of applied torque for the external rotation, internal rotation and the rotational range (internal + external rotation). Comparison of the left and the right knee of the same participant also revealed high correlations in the Pearson correlation coefficient at all applied torques. In conclusion, the Rotameter testing device for the measurement of tibial rotation showed a high inter-observer and intra-observer reliability. It is easy to perform and might be used in a wide field as a non-invasive instrument to objectively determine rotational stability and to investigate the restoration of the rotational stability after surgical procedures.

Static rotational and sagittal knee laxity measurements after reconstruction of the anterior cruciate ligament

“…The Rotameter measurements of the operated knee can be compared with the results of the healthy contralateral side which can be used as a reference for the measurements [20]. The comparison might give important information concerning a possible undercorrection but also an overcorrection of rotational stability or an objectivation of associated injuries.…”

“…Due to the strict inclusion criteria and the complex measurements on the patients, the amount of patients was limited. Because of the retrospective study design and the lack of a healthy control group, the postoperative measurements could only be compared with the contralateral healthy knees as high correlations of the measurements between both knees in healthy volunteers were described [20]. Therefore, possible differences in tibiofemoral rotation compared to the measurements of healthy volunteers cannot be investigated.…”

Objective measurements of static anterior and rotational knee laxity

“…The Rotameter overestimates the total range of rotation at 5, 10, and 15 Nm by an average of 5, 10, and 25°, respectively [33]. ICCs for these different torques were superior to 0.67 [34]. Regarding the second version of the Rotameter, it yields lower values for rotational laxity than the first device due to improvements in the standardization of the patient installation and joint fixation.…”

Optimal measurement of clinical rotational test for evaluating anterior cruciate ligament insufficiency

“…On the other hand, simple rotational angle change against either a simple or combined rotational torque has been utilized as an alternative clinical examination for assessing abnormal knee motion [8,16,21,26,38]. The testing conditions are generally well controlled, but it is still unknown how this rotational angle alteration is related to the rotational instability due to ACL insufficiency and further clinical knee function.…”