Twenty-three tendons from 18 consecutive patients (14 men, 4 women), mean age of 40 years (range 25–60 years) with painful midportion Achilles tendinopathy referred for surgical opinion were included. No cases had had pervious surgical treatment or inflammatory diseases. Duration of symptoms ranged from 4 to 120 months.
Sixteen patients had failed a tendon loading program. Nine patients had been treated with injection therapy (high volume saline alone, 3; high volume saline + marcaine + cortisone, 4; cortisone alone, 2). Seven patients were elite athletes (track and field, 3; football, 1; rugby, 1; acrobatics, 1; boxing 1) whereas eleven patients were non-elite (running, 10; football, 1).
Patients were asked specifically about location of tendon pain. Clinical examination was performed in a prone position with the feet hanging freely over the edge of the examination bed and evaluated by the same examiner (HA). Location of tenderness on tendon palpation was noted.
US + CD examination
Ultrasound examinations were performed in a prone position with the feet hanging freely over the edge of the examination bed. A high-resolution greyscale Ultrasound (US) and Colour + Doppler (CD) (Antares-Siemens, Germany) with a linear multifrequency (8–13 MHz) probe was used. Colour Doppler settings were standardised with a gain of 68 dB, sensitivity of 8 cm/s and a pulse repetition frequency of 1250Hz. Achilles tendon thickness, structure and blood flow was assessed by the same examiner (HA) with over 15 years experience in diagnostic musculoskeletal ultrasound. Tendon structure was defined as being normal or irregular and hypoechoic. Furthermore, the location of the hypoechogenicity (medial, ventral, lateral) was noted. The examined Achilles tendons were assessed as having normal or high blood flow. Tendons with “normal blood flow” had no detectable blood flow in the sagittal or axial plane, whereas “high blood flow” tendons exhibited at least one region with localised high blood flow in the sagittal and axial plane. Careful examination of the medial side of the Achilles tendon, starting proximally in the mid calf and moving distally, was performed to look for the plantaris tendon.
Ultrasound Tissue Characterisation (UTC)
When taking UTC scans, patients were positioned prone on the examination table with the affected ankle caudal to the edge of the examination bed. The examiner’s knee was then pushed against the forefoot of the patients in order to achieve maximal passive dorsiflexion. Scans were collected in a distal to proximal direction, and were performed by the same experienced examiner (LM). More practical details are described in .
UTC algorithms were applied to quantify the stability of grey scale levels of corresponding pixels in contiguous images over 25 images. Previous studies using histopathological tissue specimen as reference have shown that the stability of grey scale levels strongly correlates with the architecture and integrity of the tendon matrix [16–19]. Furthermore, UTC has demonstrated high intra- and inter-rater reliability [14, 15].
Validated UTC algorithms can discriminate 4 different echo-types, related to matrix integrity, and is visualised as four different colours. Type I pixels (green) represent intact, continuous and aligned collagen bundles (fibres and fasciculi); type II (blue) indicates less continuous and/or more swollen and/or more wavy collagen bundles (fibres and fasciculi); type III (red) is generated by disintegration with tendon tissue replaced by mainly disorganised, fibrillar matrix; type IV (black) is generated by complete disintegration with tendon tissue replaced by an amorphous matrix and fluid.
Regions with disintegration (echopixels type III and IV) within the midportion of the Achilles tendon were identified and recorded according to site within the midportion of the tendon (superficial, ventral, medial or lateral).
Surgery was undertaken 24 h after clinical assessment, US + CD and UTC examinations. Under local anesthesia , the medial aspect of the Achilles tendon was visualised via a minor longitudinal incision on the medial side of the Achilles tendon midportion. For determination of the presence and exact location of a plantaris tendon, the medial side of the Achilles tendon was carefully inspected. When a plantaris tendon was detected, the location in relation to the medial aspect of the Achilles tendon was documented with photographs. The surgical treatment consisted of release of the plantaris tendon followed by excision distally from the calcaneal insertion and proximally at a level slightly above the distal medial soleus musculotendinous junction. In addition, a ventral tendon scraping procedure was performed in the regions corresponding Ultrasound + Doppler-verified high blood flow on the ventral side of the Achilles tendon . The length of the longitudinal incision was 1–2 cm. All operations were performed by the same surgeon (HA).
The study was approved by University of Queen Mary ethics committee as part of a prospective study on all surgically-treated Achilles tendons at Pure Sports Medicine Clinic in London, UK. All participants provided informed consent prior to participation.