Related Experiment Video
Updated: Sep 19, 2025
A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats
Published on: May 20, 2019
A novel meniscal root refixation pull-in technique with an all-suture anchor shows biomechanical properties
Thorben Briese1, Amaris Kieninger1, Christian Peez1
1Department of Trauma, Hand- and Reconstructive Surgery University Hospital Münster Münster Germany.
Purpose:
Repair techniques for posterior meniscal root (PMMR) tears include repair with transtibial pull-out and anchors. An alternative approach uses all-suture anchors pulled in, avoiding a posterior medial portal. While clinical feasibility has been assessed, biomechanical properties of this technique remain unknown. We hypothesised that the biomechanical properties using the pull-in technique would be comparable to those achieved with conventional repair techniques.
Methods:
Fifty fresh-frozen porcine tibiae were fixed in a steel pot. Whereas in group (1) the native meniscal root was kept intact (native meniscal root (NM)), the PMMR was sectioned and refixed in groups (2)-(5): (2) Double-loaded suture anchor (screw anchor) (SA), (3) transtibial pull-out repair with two sutures (TTPO), (4) double-loaded pull-in repair with all-suture anchor that was pulled into the subcortical bone which was predrilled from retrograde direction (PULL) and (5) double-loaded push-in repair with all-suture anchor traditionally pushed into the predrilled subcortical bone in antegrade direction (PUSH). Testing was performed using a universal testing machine with 1000 cycles (5-20 N/0.5 Hz) with subsequent load-to-failure (LTF) meaning failure of the NM or refixation. Outcomes measured included LTF (N), cyclic displacement (mm), and stiffness (N/mm). The failure mode was documented macroscopically.
Study Design:
Controlled laboratory study.
Results:
No repair technique restored the stability of the NM, reaching 1064.6 ± 226.0 N in LTF (p ≤ 0.0001). Reconstructions had significantly lower LTF: SA (251.4 ± 52.8 N), TTPO (233.4 ± 50.0 N), PULL (206.2 ± 86.5 N) and PUSH (214.3 ± 55.2 N). The NM showed the highest stiffness with 156.1 ± 76.3 N/mm (p ≤ .0001) compared to (SA) 36.2 ± 10.1 N/mm, (TTPO) 33.6 ± 6.2 N/mm, (PULL) 36.8 ± 12.7 N/mm, (PUSH) 27.7 ± 6.6 N/mm. Increased displacement after 1000 cycles was shown, with (2.3 ± 0.7 mm) in PULL, only with significant differences noted between NM (1.5 ± 0.8 mm) and PUSH (3.1 ± 0.7 mm) (p ≤ .001), NM and SA (2.5 ± 0.8 mm) (p ≤ .05), and TTPO (2.1 ± 0.7 mm) and PUSH (p ≤ .05). No failures occurred during cyclic loading. Failure after LTF was always a suture cut-out at the meniscus.
Conclusion:
Current repair techniques for posterior medial root tears do not fully restore the biomechanical properties of an intact root. The new pull-in technique with an all-suture anchor which is pulled in instead of pushed in shows biomechanical properties comparable to conventional methods, especially regarding LTF.
Level Of Evidence:
There is no level of evidence as this study was an experimental laboratory study.
