Disadvantages Of Musculoskeletal Dysfunctions

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Abstract: Musculoskeletal dysfunctions such as osteoarthritis and low back pain are commonly seen among transfemoral amputees (TFAs), and are considered as secondary disabilities among amputees. The amputation surgery changes the biomechanics of transfemoral amputees abruptly. It is not unusual that the gait deviation in TFAs is commonly observed and the primary cause is muscle weakness. The amputation leads to the loss of muscle distal insertion sites and the change of muscle’s moment arm, thus the force can be generated by hip muscles is affected. These biomechanical disadvantages result in hyperlordotic posture and load increment at the intact limb. As the consequences, TFAs have a high risk of getting back pain and knee osteoarthritis at …show more content…
The articular cartilage has viscoelastic properties. This unique feature allows articular cartilage to carry out its functions, to absorb the compressive load and transmit it to the subchondral bone (Sophia Fox et al., 2009). Excessive loading on cartilage can damage the extracellular matrix and increase catabolic activity (Sun, 2010). Moreover, bone in the osteoarthritic stage has lower modulus to absorb the forces, and transfer the load back to cartilage (Leng et al., 2013). This vicious cycle will lead to knee osteoarthritis. TFAs commonly have shorter prosthesis stance duration as they are incapable to balance at the amputated leg, feel the stump pressure pain or lack of confidence to transfer weight to the prosthetic leg. They rely on intact limb in walking, climbing stairs and overcoming ramps, soft ground (Kendell et al., 2016). Hence, the load at sound limb is consistently high. As a result, osteoarthritic changes are more pronounce at the intact limb as the cumulative of excessive joint load deforms articular cartilage (Maly, 2008). There is another interesting finding in TFAs population. According to Chang et al, the knee adduction moment of the intact leg was 32% more than the prosthetic side (Diagram 3) (Chang et al., 2011). A larger knee adduction moment means a higher torque trying to rotate the tibia into varus position, and leads to higher stress at the medial side of the knee. Therefore, the knee adduction moment has a significant correlation with the severity of medial compartmental knee OA (Maly,

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