Operative and non-operative treatment regimens for Achilles tendon ruptures vary greatly but commonly involve rigid casting or functional bracing. The aim of our study was to investigate the extent of tendon apposition following such treatments.

Twelve fresh-frozen, adult below knee lower-extremity cadaveric specimens with intact proximal tibiofibular joints were used. Each was prepared by excising a 10cm × 5cm skin and soft tissue window exposing the Achilles tendon. With the ankle in neutral position, the tendon was transfixed with a 2mm k-wire into the tibia, 8cm from its calcaneal insertion. A typical post-rupture gap was created by excising a 2.5cm portion of tendon between 3.5cm and 6cm from its calcaneal insertion.

The specimens were then placed into a low profile walker boot (SideKICK^TM, Procare) without wedges and a window cut into the back. The distance between the proximal and distal Achilles tendon cut edges was measured and repeated with 1, 2 and 3 (10mm) wedges. Subsequently the specimens were placed into a complete below knee cast in full equinus which was also windowed.

The Achilles tendon gap (mean +/− SD) measured: 2.7cm (0.5) with no wedge, 2.3cm (0.4) with 1, 2.0cm (0.4) with 2, 1.5cm (0.4) with 3 wedges and 0.4cm (0.3) in full equinus cast.

The choice of treatment had a significant effect on tendon gap (p< 0.0001 – repeated measures ANOVA), and all pairwise comparisons were significantly different (Bonferroni), with all p< 0.001, apart from 0 wedge vs. 1 wedge (p< 0.01) and 1 wedge vs. 2 wedges (p< 0.05).

Our results showed that each wedge apposed the tendon edges by approximately 0.5cm with the equinus cast achieving the best apposition. Surgeons should consider this when planning appropriate immobilisation regimes for Achilles tendon ruptures.

During surgical reduction of ankle injuries with syndesmotic instability surgeons often use the anteroposterior (AP) and mortise radiographs to assess reduction. Current literature predicts 50% are malreduced mainly in the sagittal plane. Our aim was to develop a radiographic measure based on the lateral view to assess both the normal and abnormal fibula/tibia relationship after simulated syndesmotic malreduction and to evaluate the effect on commonly used AP and mortise measurements.

Nine fresh-frozen cadaveric specimens were dissected to the level of the syndesmosis. AP, mortise and talar dome lateral radiographs were obtained before and following syndesmosis division and posterior fibula displacement. On the lateral radiograph a line was drawn (Orthoview) from the anterior border of the fibula bisecting a line drawn from the anterior to posterior lips of the distal tibia. The ratio of the anterior-posterior segments was calculated. Also a line was drawn from the posterior border of the fibula and the distance was measured to the posterior lip of the tibia.

At 0, 2, 4 and 6mm of displacement the ratio measured 1.3±0.2, 1.1±0.2, 0.9±0.2 and 0.7±0.2 respectively with all pairwise comparisons being significantly different. Inter- and intra-observer variability varied from substantial to perfect. The only significant medial clear space (MCS) difference was on the mortise view between 0mm (2.0±0.3mm) and 6mm (2.4±0.4mm) displacement.

Our new measure of syndesmotic reduction is reproducible and can detect from 2mm of saggital fibular displacement. At maximum fibular displacement the increase in MCS was less than 1mm. This demonstrates standard mortise radiographs are poor at detecting syndesmotic reduction. An interesting observation was in all specimens prior to any displacement, the posterior fibular line always bisected the posterior lip of the tibia or lay just anterior to it, never posterior. This could serve as a useful adjunct for surgeons when assessing syndesmotic reduction intra-operatively.