Development of Achilles Tendon Elongation and Its Effect on Physical Function the First Year After Rupture

The examination of both the total and the free part of the achilles tendon of both the injured and un-injured leg is performed. The free part of the achilles tendon is defined as the distance between the proximal border of calcaneus and the musculotendinous junction of the soleus muscle. The total length of the achilles tendon is the distance between the proximal border of calcaneus and the musculotendinous junction of the medial gastrocnemius muscle. Measurement is perfomed as described by Barfod et al (1).

The examination of both the total and the free part of the achilles tendon of both the injured and un-injured leg is performed (the free part is measured from week 9). The free part of the achilles tendon is defined as the distance between the proximal border of calcaneus and the musculotendinous junction of the soleus muscle. The total length of the achilles tendon is the distance between the proximal border of calcaneus and the musculotendinous junction of the medial gastrocnemius muscle. Measurement is perfomed as described by Barfod et al (1).

Achilles tendon length is indirectly estimated clinically by use of the Achilles Tendon Resting Angle (ATRA) or the Achilles Tendon Length Measure (ATLM). The patient lies flat in prone position on the examination bed. The knee is flexed at 90 degrees and the ankle sits in relaxed position. The ATRA is determined as the angle between the corpus of the fibula and the corpus of the 5th metatarsus. The ATLM is determined as the distance from the caput of the 5th metatarsus to the surface of the examination bed. Both the ATRA and the ATLM are determined for both the injured and the uninjured leg. The difference between the healthy and the injured leg is evaluated.

Patients will fill out the ATRS questionnaire in connection to the follow-up visits in the Outpatients Department. ATRS is a patient-reported outcome measure.

This questionnaire is a part of the usual examination of the patients' function, and is used during all follow-ups in the usual care.

An endurance test where the patient stands on one leg and lifts the heel up and down until exhaustion. The number and the height of the heel rises are counted and measured and plotted into a diagram on an X-axis and Y-axis respectively. The results are then compared to the weight of the patient and the total work is estimated as area under the curve. The heel lift distance between the heel and the floor is measured in millimeters. The procedure is performed on the uninjured leg first and subsequently on the injured leg. The patient is barefoot for the heel-rise work test and stands on a flat surface with a 10 degree inclination. For these functional tests a measurement system MuscleLab (Ergotest Technology, Oslo, Norway) will be used.

The patient is sits on an examination bed with legs hanging down. The circumference of the calf is measured using a measuring tape (13 cm under apex patella).

MRI will be conducted to obtain a deeper understanding of how the different structures in the muscle-tendon complex change the first year after rupture. The MRI will be conducted at Copenhagen University Hospital Amager-Hvidovre in an Acanto 1,5 T scanner. Both lower legs will be scanned. The patient's head and upper-body are outside the scanner. Total time for the patient in the scanner is approximately 20 minutes.