Lower Extremity Biomechanics during Stair Ascent in Healthy and Total Knee Replacement Older Adults

Altered gait following total knee replacement (TKR) may increase risks for failure of joint replacements and subsequent joint replacements in both the replaced and non-replaced limb of TKR patients. Stair climbing is an activity of daily living that is more demanding than level walking and may be more robust at detecting altered gait biomechanics. Study One reviewed biomechanics during stair ambulation following TKR. Study Two compared lower extremity biomechanics during the first three steps of ascent and level walking in healthy adults. Study Three compared lower extremity biomechanics of the replaced and non-replaced limbs of TKR patients and a healthy control limb during stair ascent. Study Four utilized principal component analysis (PCA) to compare waveforms of knee biomechanical variables in TKR patients and healthy controls. Thirteen TKR participants and fifteen healthy control subjects participated. A motion analysis system and instrumented 3-step staircase were utilized to collect trials of stair ascent and level walking.

The findings of Study Two show that many sagittal plane variables for healthy subjects were smallest in level walking, larger on the first step and greatest on the second and third steps. In the frontal plane the knee was more adducted with greater abduction ROM in the step conditions. The findings of Study Three show that the loading response peak knee extension moment was greater in control and non-replaced knees compared with replaced of TKR. In addition, loading-response peak hip abduction moments were greater in the replaced and nonreplaced limb compared to controls, while the push-off peak hip abduction moment was greater in replaced compared to controls. The findings of Study Four show that peak knee abduction and internal rotation moments were elevated in TKR compared to controls.

TKR patients have compensatory gait that results in deficits in the sagittal plane, with increased demands in the frontal and transverse plane at the knee and hip in the replaced limb in addition to compensation by the non-replaced limb. Rehabilitation strategies should continue to focus on the quadriceps muscle, but should also focus heavily on other muscles surrounding the knee and hip joints for optimal recovery following TKR.