Assessment of fixation for anterior cruciate ligament reconstruction using oversized suspensory devices on full-length femoral tunnels.

BACKGROUND: In ACL repair, full-length single-diameter tunnels facilitate anatomic femoral fixation with suspensory devices, especially with outside-in techniques, and are required after accidental cortical perforation. With tunnel diameters over 6 mm, fixation resistance using regular suspensory devices may not suffice. Oversized cortical footprint devices could be a solution to guarantee fixation performance in larger tunnel diameters. This study aims to assess the biomechanical properties of ACL femoral fixation provided by two enlarged suspensory devices of similar characteristics, a fixed loop (G-Lok™ with G-Lok-XL™) and an adjustable loop (ProCinch™ with G-Lok-XL™), resting on a full-length 9 mm diameter tunnel compared to the widely accepted regular fixed-loop device (G-Lok™) on a socket tunnel. METHODS: Twenty-seven fresh frozen porcine femurs and flexor digitorum profundus tendons were randomly assigned to a study group depending on the fixation method used (N = 9). Graft-femur constructs were subjected to a traction cyclic test (5000 cycles, [50-250]N load, 1 Hz) followed by a load-to-failure test (v = 1 mm/s). Residual displacement during the cyclic test and stiffness, displacements at physiological loads, ultimate load and corresponding displacement during the load-to-failure test were determined. FINDINGS: No significant differences could be established for any parameter measured in the comparison between the control with the socket tunnel and the oversized fixations with full-length tunnels. INTERPRETATION: ACL femoral fixation achieved in full-length single diameter tunnels by using an enlarged suspension device, both with a fixed or an adjustable loop, provide similar biomechanical properties to the gold-standard fixed-loop device in a socket tunnel. Therefore, its clinical use may be safe.

Digital versus light microscopy assessment of extraprostatic extension in radical prostatectomy samples.

Focal or non-focal/extensive extraprostatic extension of prostate carcinoma is an important pathologic prognostic parameter to be reported after radical prostatectomy. Currently, there is no agreement on how to measure and what are the best cutoff points to be used in practice. We hypothesized that digital microscopy would potentially provide more objective measurements of extraprostatic extension, thus better defining its clinical significance. To further our knowledge on digital prostate pathology, we evaluated the status of extraprostatic extension in 107 consecutive laparoscopic radical prostatectomy samples, using digital and conventional light microscopy. Mean linear and radial measurements of extraprostatic extension by digital microscopy significantly correlated to pT status (p = 0.022 and p = 0.050, respectively) but only radial measurements correlated to biochemical recurrence (p = 0.042) and grade groups (p = 0.022). None of the measurements, whether conventional or digital, were associated with lymph node status. Receiving operating characteristic analysis showed a potential cutoff point to assess linear measurements by conventional (< vs. > 24.21 mm) or digital microscopy (< vs. > 15 mm) or by radial measurement (< vs. > 1.6 mm). Finally, we observed an association between the number of paraffin blocks bearing EPE with pT (p = 0.041) status (digital microscopy), and linear measurements by conventional (p = 0.044) or digital microscopy (p = 0.045) with lymph node status. Reporting EPE measurements by digital microscopy, both linear and radial, and the number of paraffin blocks with EPE, might provide additional prognostic features after radical prostatectomy.

Digital versus light microscopy assessment of surgical margin status after radical prostatectomy.

Positive surgical margin (PSM) extension reported as focal or non-focal/extensive is an important pathologic prognostic parameter after radical prostatectomy. Likewise, there is limited or no agreement on how to measure and what the best cut-off points to be used in practice are. We hypothesized that digital microscopy (DM) would potentially provide a more objective way to measure PSM and better define its clinical significance. To further our knowledge, we have evaluated PSM status in 107 laparoscopic radical prostatectomies using digital and conventional light microscopy (LM). DM evaluation detected three additional PSM cases, but no differences were seen (LM vs DM; p = 0.220). Mean linear measurement correlated to biochemical recurrence (BR) (LM, p = 0.002; DM, p = 0.001). ROC analysis identified a cut-off point to assess linear measurement by LM (3.5 mm) or DM (3.2 mm), but only digital measurement was significant for BR-free survival. Our study also evaluated a cut-off ≤ 3 mm that was associated to BR using LM (p = 0.023) or DM (p = 0.001). Finally, the number of paraffin blocks bearing PSM correlated with BR (p < 0.001) status with either LM or DM. In conclusion, DM produces similar data than LM but shows more accurate measurements. Reporting of PSM with score of ≤ 3 vs. > 3 mm linear extent using LM (3.2 mm if digital microscopy is applied) might represent an important prognostic feature after radical prostatectomy. Alternatively, reporting the number of blocks with PSM 1 vs. 2 or more might also provide important prognostic data in practice.