## 4 Discussions
\begin{table}
\begin{tabular}{l l l l} \hline
**Quadrant** & **Pre-Cut** & **Post-Cut** & \(p\)**-Value** \\ \hline Medial: & 13.3 \(\pm\) 15.3 & 15.4 \(\pm\) 13.0 & 0.281 \\ Lateral: & 33.5 \(\pm\) 15.7 & 15.7 \(\pm\) 9.7 & 0.002 * \\ Superior: & 7.6 \(\pm\) 9.3 & 10.5 \(\pm\) 2.9 & 0.249 \\ Inferior: & 2.5 \(\pm\) 2.2 & 4.9 \(\pm\) 3.6 & 0.031 * \\ \hline \end{tabular}
* denotes statistical significance.  
\end{table} 
Table 5: Comparison of mean maximal load (N) and standard deviation recorded prior to making a planned adjustment cut (\(n=3\): Left knee of Specim 1; both knees of Specim 2) compared to the post-adjustment cut measurement obtained using 9 mm neutral shim. Analyzed via paired t-test. adjustments in resection depth and angle of the patella resection, which could decrease the risk for patella under-resection and \"over-stuffing\". Pre-operative alignment may also play a role in PFJ loads which are encountered. Notably, within the two cadaveric experiments conducted, we noted increased lateral PFJ loads. While the reason these lateral PFJ loads were observed is not immediately evident, this increase may be due to overall valgus alignment of the specimens, as lateral patella tracking was appreciable pre-operatively. Altered loads of the PFJ and extensor hood, even after an optimally implanted TKR may explain why patients rarely experience the \"forgotten knee\" [21]. Various methods for evaluating the quality of PFJ management following TKR have been studied, particularly to predict excessive PFJ loads and patellar maltracking which contribute to complications including anterior knee pain [12; 13; 14]. Q-angle, lateral patellar tilt, and patellar displacement have been measured in the post-operative or intraoperative setting to assess adequate patellar tracking [3; 14]. An increase in Q-angle is associated with complications such as anterior knee pain following TKR, and this increase can be multifactorial occurring due to malrotated femoral or tibial components as well as an inadequately managed patella [3]. Lateral patellar tilt and patellar displacement, measured on a skyline axial radiograph, have also been implicated as important factors in patellar tracking, with lateral patellar tilt \(>\) 10\({}^{\circ}\) and patellar displacement \(>\) 3 mm associated with patellar maltracking [13; 22]. Lateral patellar tilt and patellar displacement are determined by patellar resection angle, patellar component medialization, as well as positioning of the femoral component [14]. A prior study has also used surgical navigation systems to assess patellar tracking intraoperatively, as well as use of a force transducer to quantify patellofemoral contact pressures [23]. Compared to these prior techniques implemented to improve patellar tracking and reduce PFJ loads, none have implemented a technique where dynamic measurements are obtained intraoperatively to guide adjustment resection of the patella in a patient-specific fashion. Patella maltracking occurring in the setting of too little tension or \"under-tensioning\" of the patella leads to reduced function and mechanical disadvantage as well [8]. Maltracking or malorientation of the extensor hood produces soft tissue pain and reduction in function as well as the prospect of increased wear in the patella resurfacing implant [9]. Important factors which contribute to patellar instability are component malposition. Oversized femoral components and/or its rotation are thought to cause patella tilting onto the trochlear grove, and resultant complications including AKP and instability. Rotation of the femoral component varies based on the alignment strategy used (mechanical or anatomical), with internal rotation of the femoral component demonstrated to correlate with poorer outcomes [15], and whilst less common, internal rotation of the tibial component, can cause increased strain on the PFJ.