The Effect of Collagen Scaffold Augmentation in Achilles Tendon Rupture Repair

Surgical complications will be recorded, such as would problems and early re-ruptures. Based on current evidence, approximately 1 in 9 patients undergoing operative repair of an acute Achilles tendon rupture developed a postoperative complication.

The Foot and Ankle Outcome Score (FAOS) is a open-source, validated piece of instrument to evaluate overall foot and ankle function . It is extensively used in foot and ankle clinical research and is calculated using multiple Likert scale questions which are organized into 5 sub-categories: symptoms, pain, activities of daily living (ADL), sports and quality of life (QOL). The answers in each subcategory are then converted into a score from 0 to 100; with 100 resembling no symptoms and 0 resembling severe symptoms.

B-mode ultrasound will be used to locate and measure the maximum thickness of the Achilles tendon (4-9mm) using a greyscale sonographic image. To minimize anisotropic effect, the transducer will be adjusted to ensure the ultrasound beam is perpendicular to the tendon fibers.

Doppler mode is used to measure tendon neovascularity. The transducer is placed perpendicular to obtain a sagittal view of the Achilles tendon. The assessor screens the tendon for the area of maximum Doppler flow and takes a sonographic image. The Öhberg score is then determined during the US examination. Scores range from 0 to 3, with a higher score indicating more Doppler flow in the peritendinous and intratendinous tissues. Pressure from the transducer will be kept to a minimum to prevent occlusion of neovascularization

Shear wave elastography (SWE) is a technique used to quantify the stiffness of soft tissue and provide objective, quantitative data for clinical references. It works by using a focused ultrasound beam to generate shear waves within the tissues, and measuring the velocity of their propagation. To measure the stiffness of a tendon, the optimal scan plane must first be identified, and the SWE function is then activated with a measurable range of stiffness standardized at 0-600 kPa. An electrogram is obtained and stored, and the stiffness of the tendon is measured using a Q-box tool. The Q-box is circular and set to 2 mm in diameter, covering only the Achilles tendon without including adjacent soft tissues. The mean stiffness of the tendon is measured for each Q-box.

Achilles tendon resting angle will be measured in flexed positions . The participant will be positioned prone with the knee passively flexed to 90 degrees on visual inspection. A goniometer will be placed on the lateral, plantar aspect of the foot is used to measure the foot angle. The stationary arm of the goniometer is aligned with the lateral midline of the lower leg, extending towards the knee, while the movable arm is aligned with the calcaneal tuberosity, parallel to the long axis of the foot. To ensure accuracy, the measurement is repeated two to three times, and the average resting angle is calculated.

Two tests will measure calf muscle strength. At weeks 6 and 3, and 6 months and 1 year, a handheld dynamometer will measure strength while lying down. At 6- and 12-month follow-up, a heel raise test will measure strength. Participants will raise their heels until they tire, with two fingertips per hand on a wall for balance. The heel raise will be done at a rate of 30 per minute, 2 seconds each, and following a metronome

The weight-bearing lunge test measures ankle dorsiflexion ROM and gauges the flexibility of the gastrocnemius and soleus muscle complex. It is a standardised test that involves standing with heels on the ground and knees aligned with the second and great toe. Participants lunge forward until their knee makes contact with the wall without lifting their heel. The distance between the big toe and the wall is then measured using a ruler

Participants will perform three one-legged counter-movement jumps on a pressure mat (Tekscan, USA) with jump height (cm) calculated from flight time. After demonstration and submaximal practice jumps, the patient executed maximal jumps from a standing position by rapidly squatting (flexing knee/hip/ankle) before exploding upward. The highest jump was recorded, with NPRS-reported Achilles tendon pain immediately post-test.

The pathological tendon's oxygenation and vascularity were quantified using a multiwavelength photoacoustic ultrasound (PAUS) system equipped with a 7Hz probe and dual-wavelength LED sources (850nm/750nm). The participant assumes a prone position with heels extended beyond the examination table. The probe is positioned on the target tendon, with mode-specific presets selected ("Deep PA" for vascularity at 850nm; "Deep Oxy" for oxygenation at 750nm). Each 20-second acquisition captures 200 frames, with two repeated scans per mode to ensure data reliability.

Participants will be advised to avoid physical exercise and hot baths before the procedure to ensure data reliability. Each participant will rest in a seated position for 10 minutes followed by 2 minutes without socks. The room will be maintained at 20-24°C. The infrared camera will be positioned one meter from the participant, using a ThermaCam FLIR-T8210. Images will be analyzed with ThermaCAM Researcher Pro 2.8 SR-1 software, and a rectangular area covering the Achilles tendon will be used for temperature assessment.

The Achilles Tendon Total Rupture Score (ATRS) is a validated patient-reported outcome measure specifically designed to assess functional recovery in patients with complete Achilles tendon ruptures. This 10-item questionnaire evaluates symptoms and physical activity limitations, with each item scored on a 0-10 Likert scale (0 = severe disability/unable to perform, 10 = no disability/full function), yielding a total score ranging from 0 (worst) to 100 (best). The ATRS covers three key domains: pain (during rest and activity), functional impairment (walking, stair climbing, running, jumping), and patient confidence in the affected limb.