Biomechanical analysis of knee flexion and extension

Quadriceps torque curve pattern in patients with anterior cruciate ligament injury

“…The relationship between quadriceps strength and forward displacement of the tibia has been described previously. Smidt [7] reported that during quadriceps contraction, a maximal forward sheer force of 35 kg was exerted on the tibiofemoral joint when the knee was in 15°of flexion. Grood et al [3] and Jurist and Otis [4] reported that when resistance is applied to the shin during quadriceps contraction, it acts to displace the tibia forward for the range of movement of the knee from full extension to slight flexion.…”

Joint forces in extension of the knee: Analysis of a mechanical model

“…The main difference between our results and others is seen at straighter knee angles, where we suggest the moment arm to be shorter than has earlier been reported. This, together with the physiological muscular length-tension relationship, may be one explanation why knee extending strength decreases during the last 30-40" of knee extension (Williams & Lindahl et al 1969, Haffajee et al 1972, Smidt 1973. It may also explain the difficulty in acheiving the last few degrees of knee extension in clinical practice.…”

Factors Influencing Results of High Tibial Osteotomy in Gonarthrosis

“…The relations to the initial angle were discussed above, but the correlation to the correction achieved by operation deserves mention here: We have observed in some patients that there is a loss of correction into varus already during the period of healing. In the normal knee joint, there is a varus stress during the stance phase of gait (Smidt 1973), and it is reasonable to assume that it still was present after the tibial osteotomy in the patients whose deformity was not fully corrected. The unsatisfactory mechanical qualities of the medial tibial condyle in arthrosis (Lereim & Goldie 1973) are further deteriorated by osteotomy.…”