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Similar Histopathological Picture in Males with Achilles and Patellar Tendinopathy

MAFFULLI, NICOLA1; TESTA, VITTORINO2; CAPASSO, GIOVANNI3; EWEN, STANLEY W.4; SULLO, ALESSIO5; BENAZZO, FRANCESCO6; KING, JOHN B.7

Medicine & Science in Sports & Exercise: September 2004 - Volume 36 - Issue 9 - pp 1470-1475
CLINICAL SCIENCES: Clinical Investigations

MAFFULLI, N., V. TESTA, G. CAPASSO, S. W. EWEN, A. SULLO, F. BENAZZO, and J. B. KING. Similar Histopathological Picture in Males with Achilles and Patellar Tendinopathy. Med. Sci. Sports Exerc., Vol. 36, No. 9, pp. 1470–1475, 2004.

Purpose: To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons.

Methods: In males, we studied biopsies from tendinopathic Achilles (N = 28; average age 34.1 yr) and patellar tendons (N = 28; average age 32.1), Achilles tendons (N = 21; average age 61.8 yr) from deceased patients with no known tendon pathology, and patellar tendons (N = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Hematoxylineosin stained slides were interpreted using a semiquantitative grading scale (0: normal to 3: maximally abnormal) for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (kappa statistics).

Results: The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 ± 5 and 10.4 ± 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low.

Conclusions: Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etiopathological mechanism may have acted on both these tendon populations.

1 Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, Stoke on Trent, Keele, UNITED KINGDOM; 2 Department of Sports Traumatology, Dynamic Center, Angri, ITALY; 3 Second University of Naples, Faculty of Medicine and Surgery, Department of Orthopaedics and Traumatology, Napoli, ITALY; 4 Department of Pathology, University of Aberdeen Medical School, Aberdeen, UNITED KINGDOM; 5 Second University of Naples, Faculty of Medicine and Surgery, Department of Experimental Medicine, Human Physiology Section, Napoli, ITALY; 6 Department of Orthopaedics and Traumatology, Faculty of Medicine, University of Pavia, I.R.C.C.S.-Policlinico San Matteo, Pavia, ITALY; and 7 Department of Orthopaedics, The Royal London Hospital Trust, Whitechapel, London, UNITED KINGDOM

Address for correspondence: N. Maffulli, Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, North Staffordshire Hospital, Thornburrow Drive, Hartshill, Stoke on Trent, Staffordshire, ST4 7QB, England; E-mail: n.maffulli@keele.ac.uk.

Submitted for publication July 2002.

Accepted for publication May 2004.

©2004The American College of Sports Medicine