## 4 Discussion
### Considerations When Using Fresh-Frozen Cadaver Specimens  
Our study was conducted using fresh-frozen human cadaver specimens obtained from the Anatomical Gift Program at the University of Southern California [35]. This program maintains strict long-term storage, controlled thawing, and preparation protocols for human cadavers. The cadaver specimens were delivered on the morning of the study. Including preparation time by the surgeons and use in the study, the cadavers were outside refrigerated storage for about 4.5 h. Between cadaver preparation and the study, the prepared cadavers were kept refrigerated. As part of preparation, our surgeons resected  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & **Rod Implant** & **U Implant** & _Baseline_ **Suture** \\ \hline \multirow{4}{*}{\begin{tabular}{c} **Translation** \\ (mm) \\ \end{tabular} } & Both fingers constrained & \multirow{2}{*}{15.34} & \multirow{2}{*}{17.14} & \multirow{2}{*}{22.68} \\  & \(\leftarrow\)_case_\(1\) — & & & \\ \cline{2-4}  & Index finger constrained & & & \\ \cline{2-4}  & \(\leftarrow\)_case_\(2\) — & & & \\ \cline{2-4}  & Difference & \multirow{2}{*}{\(-\)10.05} & \multirow{2}{*}{\(-\)9.07} & \multirow{2}{*}{\(-\)13.01} \\  & \(\leftarrow\)_(case_\(2\) — _case_\(1\)) — & & & \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} **Mediolateral** \\ **Translation** \\ (mm) \\ \end{tabular} } & Both fingers constrained & \multirow{2}{*}{0.50} & \multirow{2}{*}{7.06} & \multirow{2}{*}{3.90} \\  & \(\leftarrow\)_case_\(1\) — & & & \\ \cline{2-4}  & Index finger constrained & \multirow{2}{*}{5.08} & \multirow{2}{*}{3.72} & \multirow{2}{*}{7.09} \\  & \(\leftarrow\)_case_\(2\) — & & & \\ \hline \multirow{4}{*}{
\begin{tabular}{c} **Implant Rotation** \\ (counterclockwise \\ is positive) \\ \end{tabular} } & Both fingers constrained & \multirow{2}{*}{7.45\({}^{\circ}\)} & \multirow{2}{*}{\(-\)5.29\({}^{\circ}\)} & \multirow{2}{*}{\(\overbrace{\)}} \\  & \(\leftarrow\)_case_\(1\) — & & & \\ \cline{2-4}  & Index finger constrained & \multirow{2}{*}{24.63\({}^{\circ}\)} & \multirow{2}{*}{6.12\({}^{\circ}\)} & \\  & \(\leftarrow\)_case_\(2\) — & & & \\ \cline{2-4}  & Difference & \multirow{2}{*}{17.18\({}^{\circ}\)} & \multirow{2}{*}{11.41\({}^{\circ}\)} & \\  & \(\leftarrow\)_(case_\(2\) — _case_\(1\)) — & & & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparing the translations and rotation of the implants (and suture) when constraining only the index finger versus keeping both fingers unconstrained—measurements from one specimen (see Figure 2).  
unnecessary skin, fat, and muscle tissue from the forearm to slow down decomposition (see Figure 2).  
The study was conducted in an air-conditioned Bio-Safety Level 2 (BSL-2) facility maintained at 16 \({}^{\circ}\)C. During the study, the cadaver was repeatedly irrigated using medical-grade buffered saline to maintain tissue properties. Previous works involving studies on fresh-frozen human cadavers observed no significant changes to the tendons' biomechanical properties relevant to our work as a result of the freeze-thaw cycle or the 4.5 h experiment duration used here [16; 17; 36; 37].  
Additionally, we used computer-controlled precision robotics to quickly perform 200 trials (5 repetitions of 20 paddle orientations at each of 10 input tendon tensions) for each of the four test cases (see Section 2: Testing Protocol) of the rod implant in just 3.5 h. With only three test cases, the U implant was validated in less time. We also had a rehearsal prior to our study to allow time to practice cadaver preparation, instrumentation, and tune our robotic testbed controllers.