## 3 Results  
### In-Vitro Sensor Experiment  
Multiple sensor readings were taken with the Medical Model leg set-up using different configurations of adjustment shims. Four sensor readings were taken with four different shims that increased in thickness by increments of 1 mm, from 6 mm to 9 mm. Each sensor reading had three distinct peaks in amplitude over time. The shape of the amplitude peak for a single line trace was visibly very similar for all three amplitude peaks in the reading. Minimal relative load was recorded by the inferior sensor during all sensor readings.  
With the 6 mm shim, the highest observed load was recorded by the lateral sensor, while the thicker shims resulted in the superior sensor recording the highest load. As the thickness of the shim increased from 6 mm to 9 mm, the relative load recorded by the superior sensor increased (Figure 7). With the 6 mm shim, the highest relative load of the lateral sensor was considerably higher than the medial sensor. However, with a shim depth of 7 mm or thicker, the highest relative load of the lateral sensor and the medial sensor were very similar. There was a significant difference between the four readings (\(p\leq 0.01\)). There was also a significant difference between the highest load of the superior sensor each time the thickness of the shim was increased (6 mm and 7 mm shim, \(p\leq 0.01\); 7 mm and 8 mm shim, \(p\leq 0.01\); 8 mm and 9 mm shim, \(p\leq 0.01\)).  
The 6 mm 2.5\({}^{\circ}\) shim was attached to the sensor in two different orientations, such that forces could be measured as the plane of the angle of the patella was changed. First, the shim was attached to the sensor so that the thickest part of the shim was on the lateral side of the patella and a sensor reading was performed. The highest relative load was recorded by the lateral sensor, followed by the superior sensor. The relative load of the medial sensor was considerably lower than the lateral and superior sensor. The shim was then oriented so the thickest part of the shim was on the medial side of the patella. The highest relative load was subsequently recorded by the superior sensor, closely followed by the medial sensor and then the lateral sensor. The highest relative load recorded by the superior sensor was very similar in both sensor readings. The most significant changes in recorded load were demonstrated by the lateral and medial sensors (Figure 8). When comparing the two sensor readings, the highest relative load recorded by the medial and lateral sensors were significantly different (\(p\leq 0.01\), \(p\leq 0.01\), respectively). There was no significant difference between the superior sensor load in the two readings recorded (\(p=0.57\)).  
Figure 8: Graph of dynamic time warping analysis performed for the medial sensor load measurements obtained in an in vitro experiment using a model knee. Trials performed for the 6 mm 2.5\({}^{\circ}\) angled shims were consolidated and standardized by time, demonstrating the changes in measured force based on shim angle orientation. Red = 6 mm neutral shim, Green = 6 mm 2.5\({}^{\circ}\) medial angle shim, Blue = 6 mm 2.5\({}^{\circ}\) lateral angle shim. X-axis denotes Time Index (total of 12 s), and Y-axis denotes Average Force (in mV).  
Figure 7: Graph of dynamic time warping analysis performed for the superior sensor load measurements obtained in an in vitro experiment using a model knee. Trials performed for the 6 mm to 9 mm neutral shims were consolidated and standardized by time, demonstrating the increase in measured force observed with each incremental increase in shim size. Purple = 6 mm neutral shim, Blue = 7 mm neutral shim, Green = 8 mm neutral shim, Red = 9 mm neutral shim. X-axis denotes Time Index (total of 12 s), and Y-axis denotes Average Force (in mV).