Specimen testing

Specimens were loaded in an Instron 8874 servo-hydraulic materials testing machine (Instron, High Wycombe, UK). The FDL tendon was identified proximally at the musculotendinous junction and sectioned. The proximal tendon end was then held using an established technique in a freeze clamp attached to the actuator of the testing machine [23]. The specimen was positioned on the machine under the actuator so that the load would be applied in line with the physiological line of pull of the FDL tendon (Fig. 3).

Specimen set up. The foot was fixed into a custom made aluminium tray using Steinmann pins and acrylic cement. The FDL tendon was fixed to the hydraulic arm of the Instron machine using a freeze clamp and then loaded

The FDL tendon was preloaded to 100 N (ramp rate 10 N/s for 10 s). Baseline digital photographs were taken of the tendon insertion point. Cyclic loading from 50 to 150 N was then commenced at a rate of 1 Hz, for 1000 cycles. Digital photographs were taken every 100 cycles until completion of testing. For each photograph a ruler was placed next to the wound so that accurate scale measurements of tendon-bone displacements could be made using a digital software program [12]. Following cyclic loading, a load to failure test was performed, at a rate of 1000 mm per minute.

Ethics approval was obtained from the Tissue Management Committee of Imperial College Healthcare Tissue Bank (Application No. {"type":"entrez-nucleotide","attrs":{"text":"R17009","term_id":"770619","term_text":"R17009"}}R17009).