Biomechanical testing of lateral and medial ligament reconstruction using bone anchors with autologous resident tissue: influence of different reconstruction techniques on stability and mobility.

Introduction: The optimal surgical technique for chronic ankle instability remains disputable. This study had two main questions: the effect of additional medial collateral ligament (MCL) stabilisation in ankle instability and comparison of open and arthroscopic surgical techniques for lateral ligament repair.

Materials and methods: We used 10 fresh-frozen cadaver feet (Science Care, Phoenix, AZ, USA) per group. Eight states were tested in an open surgery group: native; MCL cut; MCL repair; anterior talofibular ligament (ATFL) cut; calcaneofibular ligament (CFL) cut; MCL re-cut + ATFL repair; MCL re-cut + AFTL and CFL repair; and MCL, ATFL, and CFL repair. Three states were tested in an arthroscopic group: Native; ATFL cut; and ATFL repair. A multidirectional loading test with five different movements (anterior translation (AT), supination (SUP), pronation (PRO), internal rotation (IR), and external rotation (ER)) was performed using a robotic system with six degrees-of-freedom.

Results: Refixation of the ATFL and CFL resulted in significant reductions in AT, IR, and SUP laxities (p < 0.05). Compared to this we observed a significant reduction of ER and PRO laxity when the MCL was additionally repaired ("MCL, ATFL and CFL repair") (p < 0.05). The outcomes of "MCL, ATFL and CFL repair" of the open procedure showed no significant differences in AT, SUP and IR laxity in the different ankle positions to the outcomes of "ATFL repair" of the arthroscopic procedure (p > 0.05).

Conclusion: Lateral ligamentoplasty leads to stabilisation of the ankle joint in AT, IR and SUP. Additional medial stabilisation resulted in further stabilisation, highlighting the relevance of preoperative and intraoperative evaluations of the medial ankle ligaments treating ankle instability. The stabilisation of the ankle joint by open and arthroscopic techniques was comparable for lateral ligament repair.