Aspects of aetiology, pathoanatomy and diagnostic methods in chronic mid-portion achillodynia

Abstract

The objectives of this thesis are to study aetiology and pathoanatomy, and to evaluate diagnostic methods in patients with long-standing pain and tenderness localised to the mid portion of the Achilles tendon. Treatment had failed to relieve symptoms prior to referral to our clinic, where some of these patients underwent surgical treatment.

Fifty eight patients, derived from 60 consecutive operations, were analysed regarding history, clinical assessment, ultrasound, histopathology and outcome of surgery. One third of the patients were not used to any form of vigorous physical activity. Ultrasonographic pathology was observed in 54 out of 59 examinations. Macroscopically diseased tendon tissue showed marked histopathological changes. At the follow-up to surgery, after in median 25 months (range 12-50), there was an overall satisfactory result in 75% of the patients.

Topical applications of ketoprofen, a hydrophilic non-steroidal anti-inflammatory drug, in patients in surgery for chronic tendon disorders revealed high concentrations of ketoprofen in fat, paratenon and tendon, while plasma levels were found to below. The results indicated a direct penetration and that tissues act as a reservoir for ketoprofen. No attempt was made to study clinical effects.

Tendon biopsies from 40 surgically treated patients revealed abnormal fibre structure and arrangement, focal variations in cellularity, rounded nuclei, decreased collagen stainability and increased non-collagenous matrix. Increased vascularity was seen in 26 out of the 40 subjects. Inflammatory cell infiltration was not found. A semi-quantitative grading, using a total tendon score, had a median of 21 (6-24) compared to 0 (0-13)in control biopsies (p<0.001). The volume-density estimation of glycosaminoglycan-rich areas had a median of 0.47 (0-0.86) in patients and 0 (0-0.07) in controls (p<0.001). A percutaneous core biopsy technique, guided by ultrasound and performed under local anaesthesia, turned out to be a reliable and valid tool, which can be used in clinical and experimental in vivo studies of Achilles tendon disorders.

Gadolinium contrast enhancement improved the imaging of intra-tendinous signal abnormality on Tl-weighted magnetic resonance images. The increased amount of extracellular glycosaminoglycans, highly fixed negatively charged macromolecules with water retaining capacity, may contribute to explain this finding.

Intra-tendinous alterations were imaged with contrast medium enhanced magnetic resonance and with ultrasound in 20 patients with achillodynia. Core biopsies were obtained from ultrasound hypoechoic and normoechoic regions. The increased signal abnormality in gadolinium contrast enhanced Tl-weighted images revealed a larger volume of the lesion compared with ultrasound. Hypoechoic areas showed a markedly abnormal tendon structure. However, moderate pathology was found also in the neighbouring normoechogenous areas within the same tendon, indicating a more generalised disorder than imaged by echogenic properties.

In conclusion, the data and the new tools presented in this thesis encourage further studies including treatment on the Achilles and other tendon disorders.