Changes in axial tibial rotation after anterior cruciate ligament sectioning were evaluated in 14 fresh human knee joints. Simulation of vertical stance in a quadriceps-stabilized knee was performed. Internal and external rotational torques were applied before and after anterior cruciate ligament sectioning. Pivot shift tests were done in the intact and anterior cruciate ligament sectioned knee. Results of pivot shift tests were all negative before sectioning and positive after isolated sectioning. No significant change in axial rotation occurred between the intact and sectioned knee for external rotation (P = 0.24) or internal rotation (P = 0.12). Presence of a load at the femoral housing in both the intact and ligament-sectioned knees caused a significant change in external rotation (P < 0.0001). No significant change was noted in internal rotation between loaded and unloaded states (P = 0.70). Total tibial rotation in the intact knee was noted to vary between 31 degrees at 0 degree of flexion and 42 degrees at 60 degrees of flexion. These results suggest that the anterior cruciate ligament does not play a significant role in limiting axial rotation and that rotational instability is not a major factor after isolated anterior cruciate ligament rupture.

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Individuals with weak or absent quadriceps who wish to walk independently are prescribed knee-anklefoot orthoses (KAFOs). New stance control orthosis (SCO) designs automatically release the knee to allow swing phase flexion and extension while still locking the joint during stance. Twenty-one participants were fitted unilaterally with the Dynamic Knee Brace System (DKBS), a non-commercial SCO. Thirteen subjects were experienced KAFO users (average 28 + 18 years of experience) while eight were novice users. Novice users demonstrated increased velocity (55 vs. 71cm/sec, p = 0.048) and cadence (77 vs. 85 steps/min, p 5 0.05) when using the DKBS over the traditional locked KAFO. Experienced KAFO users tended to have reduced velocity and cadence measures when using the SCO (p 5 0.10). Knee range of motion was significantly greater for the novice group than for the experienced group (55.2 + 4.8 vs. 42.6 + 3.88, p = 0.05). Peak knee extension moments tended to be greater for the experienced group (0.29 + 0.21 vs. 0.087 + 0.047 Nm/kg, p = 0.09). This report describes gait changes during the introductory phase of DKBS adoption. Experienced KAFO users undoubtedly had ingrained gait patterns designed to compensate for walking with a standard locked KAFO. These patterns may have limited the ability of those users from taking full and immediate advantage of the SCO capabilities. Also, alternate SCO systems may engender different results. Comparison studies and longer term field studies are needed to clarify benefits of the various bracing options.

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This report presents objective motion analysis measurements of 14 stance control orthoses (SCO) users during a prospective open-enrollment 6-month clinical field trial. Participants were fitted with a Dynamic Knee Brace System (DKBS) which is a novel electromechanical SCO developed by the authors. Seven of the 14 subjects that had been prescribed but did not use a KAFO at the time of enrollment were defined as novice users. Those subjects who at the time of enrollment were using a locked KAFO for ambulation were defined as experienced users. Results showed that all subjects significantly increased peak knee flexion from 49.0 +/- 15.5 degrees to 55.9 +/- 11.4 degrees between the initial and six month tests (p = 0.02). They also tended to increase peak hip flexion from 39.6 +/- 13.4 degrees to 46.0 +/- 14.5 degrees between the 3 month and 6 month tests (p = 0.09). Novice users significantly increased velocity from 74.7 +/- 19.4 cm/s to 81.2 +/- 19.0 cm/sec between the initial and 3-month tests (p = 0.005). These same users increased stride length from 109 +/- 15.3 cm to 112 +/- 16.6 cm over the same time period (p = 0.008). Experienced KAFO users, however, tended to increase velocity from 68.8 +/- 20.5 cm/s to 83.2 +/- 16.8 cm/s at 3 months (p = 0.06). This was combined with a significant increase in cadence from 76.2 +/- 14.1 steps/min to 83.9 +/- 8.3 steps/min between the initial and 3 month tests (p = 0.05). Joint kinetics showed no changes for users over the duration of the testing period. These results indicate that KAFO users make significant gains in temporodistance measures, while changes in joint kinematics take longer to develop.

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