This study aimed to ascertain whether stabilising only the AITFL is enough to prevent talar shift, and to test a simple, novel technique to reconstruct the AITFL.

Twelve cadavers were used. Talar shift was measured following: 1- no ligaments cut; 2- entire deltoid ligament division; 3- group A (5 specimens) PITFL cut whilst group B (7 specimens) AITFL cut; 4- group A had AITFL divided whilst group B had the PITFL cut. Reconstruction of the AITFL was performed using part of the superior extensor retinaculum as a local flap. Measurement of talar shift was then repeated.

With no ligaments divided, mean talar shift was 0.8mm for group A and 0.7mm for group B. When the deltoid ligament was divided, mean talar shift for group A was 4.8mm compared to 4.7mm in group B (P=1.00). The mean shift in group A after PITFL division was 6.0mm, increasing the talar shift by an average of 1.2mm. In group B after AITFL division mean talar shift was 8.3mm (P=0.06), increasing talar shift by an average of 3.6 mm. After division of the second tibiofibular ligament, mean talar shift in group A measured 10.0mm and in group B was 10.9mm(P=0.29).

Three times more talar shift occurred after the AIFTL was divided compared to the PITFL. Repairing just the PITFL (for example by fixation of the posterior malleolus avulsion fracture) may not adequately prevent talar shift while reconstruction of the AITFL potentially restores ankle stability.

Adequate perpendicular access to the posterolateral talar dome for osteochondral defect repair is difficult to achieve and a number of different surgical approaches have been described. This cadaveric study examined the exposure available from various approaches to help guide pre-operative surgical planning.

Four surgical approaches were performed in a step-wise manner on 9 Thiel-embalmed cadavers; anterolateral approach with arthrotomy, anterolateral approach with anterior talo-fibular ligament (ATFL) release, anterolateral approach with antero-lateral tibial osteotomy, and anterolateral approach with lateral malleolus osteotomy. The furthest distance posteriorly which allowed perpendicular access with a 2mm k-wire to the lateral surface of the talar dome was measured from the anterior aspect of the talar dome.

The mean antero-posterior diameter of the lateral talar domes included in this study was 45.1mm. An anterolateral approach to the ankle with arthrotomy provided a mean exposure of the anterior 1/3rd of the lateral talar dome. ATFL release increased this to 43.2%. A lateral malleolus osteotomy provided superior exposure (81.5% vs 58.8%) compared to an anterolateral tibial osteotomy.

Only the anterior half of the lateral border of the talar dome could be accessed with an anterolateral approach without osteotomy. A fibular osteotomy provided best exposure to the posterolateral aspect of the talar dome and is recommended for lesions affecting the posterior half of the lateral talar dome.

There is debate whether a home run screw (medial cuneiform to 2nd metatarsal base) combined with k-wire fixation of 4th & 5th rays is sufficient to stabilise Lisfrance injuries or if fixation of the 3rd ray is also required. Unlike the 2nd, 4th and 5th TMTJ, stabilisation of the 3rd requires either intra-articular screw or a cross joint plate which both risk causing chondrolysis and/or OA.

Using 8 Theil embalmed specimens, measurements of TMTJ dorsal displacement at each ray (1st to 5th) and 1st – 2nd metatarsal gaping were made during simulated weight bearing with sequential ligamentous injury and stabilisation to determine the contribution of anatomical structures and fixation to stability.

At baseline mean dorsal TMTJ displacement of the intact specimens during simulated weight bearing (mm) was: 1st: 0.14, 2nd: 0.1, 3rd:0, 4th: 0, 5th: 0.14. The 1st-2nd IM Gap was 0mm. After transection of the Lisfranc ligament only, there was 1st-2nd intermetatarsal gaping (mean 4.5mm), but no increased dorsal displacement. After additional transection of all the TMTJ ligaments dorsal displacement increased at all joints (1st: 4.5, 2nd: 5.1, 3rd: 3.6, 4th: 2, 5th: 1.3). Stabilisation with the home run screw and 4th and 5th ray k-wires virtually eliminated all displacement. Further transection of the 3rd/4th inter-metatarsal ligaments increased mean dorsal displacement of the 3rd ray to 2.5mm. K-wire fixation of the 3rd ray completely eliminated dorsal displacement.

The results suggest that stabilising the 2nd and 4/5th TMTJs will stabilise the 3rd if the inter-metatarsal ligaments are intact. Thus 3rd TMTJ stability should be checked after stabilising the 2nd and 4/5th. Provided the intermetatarsal ligaments (3rd-4th) are intact the 3rd ray does not need to be stabilised routinely.