Alignment-dependent changes in tibiofemoral contact mechanics after selective medial soft tissue release during...

To evaluate tibiofemoral contact mechanics after selective superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL), and posterior oblique ligament (POL) release following transtibial pullout (TPO) repair of medial meniscus posterior root tears. The primary question was whether release reduces medial contact pressure (CP) compared with isolated repair and whether pressure-reduction patterns differ by release site.

18 fresh-frozen human knees were assigned to sMCL, dMCL, or POL release groups (n = 6 each). CP, peak pressure (PP), and contact area were measured at full extension in the intact, root tear, isolated repair, and release states under 2°/5° external rotation, 2°/5° internal rotation (IR), and 30%/40%/60%/70% tibial plateau width (TPW). Linear mixed-effects models with Bonferroni-adjusted comparisons were used.

Isolated repair produced higher medial CP than intact in the sMCL, dMCL, and POL groups (mean differences: 0.52, 0.58, and 0.57 MPa, respectively; all p < 0.05). sMCL and dMCL release reduced medial CP to values not significantly different from intact, whereas POL release showed smaller reductions than sMCL under rotational loading. Medial PP remained elevated after dMCL release at 30% TPW and POL release at 5° IR (mean difference, 2.66 MPa (0.41-4.90), p = 0.012; and 2.44 MPa (0.01-4.87), p = 0.048, respectively).

Selective medial soft-tissue release reduced medial CP after TPO repair under static full-extension knee but did not fully normalize tibiofemoral loading. sMCL release showed the most consistent medial CP reduction; however, this finding should be interpreted as exploratory rather than definitive evidence of superiority.