Joint, Pelvis, And Trunk Excursions Of Ascending Stairs In Individuals With A Type Ia Rotationplasty

Type Ia rotationplasty is a limb-salvage surgery that repurposes the ankle joint as the new knee joint to achieve active ‘knee’ flexion/extension. The procedure is recommended for patients who desire a more active lifestyle. Ascending stairs is critical to functional independence but has not been examined in individuals with rotationplasty. PURPOSE: To examine lower-limb joint, pelvis, and trunk excursions in stair ascent in individuals with rotationplasty. METHODS: Nine male participants (15.7 ± 5.1 years) executed 4 trials of ascending three stairs (15.24 cm tall, 24.13 cm deep) leading with each limb (surgical [SL], intact [IL]). 3D kinematics were captured via 13 infrared cameras (120 Hz). The swing phase of the lead limb and the stance phase of the trail limb were examined in the middle step. Excursions (°) were calculated in each plane (sagittal [X], frontal [Y], transverse [Z]) as the joint range of motion for the ankle, knee, hip, pelvis, and trunk during each phase. 2x3 (leading limb x plane) RMANOVAs were conducted for each phase. α = .05. RESULTS: When the SL was leading (swing), there was less prosthetic ankle excursion in all planes (SL: X 9.7 ± 1.7°, Y 1.7 ± 1.1°, Z 6.9 ± 2.0°; IL: X 46.3 ± 7.3°, Y 18.3 ± 7.1°, Z 31.1 ± 6.0°) (p < .001), sagittal knee excursion (SL: 44.7 ± 18.3°; IL: 92.2 ± 11.3°) (p = .002), and greater pelvis transverse excursion (SL: 43.7 ± 8.6°; IL: 38.3 ± 5.6°) (p = .04) compared to IL leading. During stance, IL ankle (SL: X 12.3 ± 1.6°, Y 2.2 ± 1.4°, Z 7.5 ± 2.5°; IL: X 46.4 ± 7.3°, Y 19.0 ± 8.6°, Z 27.8 ± 5.8°) and knee (SL: X 49.3 ± 20.7°, Y 6.6 ± 2.1°, Z 5.0 ± 1.8°; IL: X 87.2 ± 15.5°, Y 21.3 ± 4.8°, Z 24.0 ± 9.2°) excursion was greater in all planes (p < .001) than SL. There were no differences between limbs for hip and trunk during either phase. CONCLUSIONS: Individuals with rotationplasty ascend stairs with greater IL motion regardless of leading limb. When the SL was leading, there was ~50% less motion in the ‘knee’ as it ascended to the next step, compensating driving upwards and rotating with the IL. If the IL was leading, greater excursion in all planes was executed in the IL knee and ankle as a potential compensation for reduced motion from the SL, suggesting limited power generation of the SL during stance. During prolonged stair ascension, asymmetric limb kinematics may result in early fatigue, heightened fall risk, or stair avoidance. Supported by: Children's Hospital Colorado and Colorado School of Mines Collaborative Pilot Grant