Excessive apoptosis in patellar tendinopathy in athletes

Lian, Øystein, Scott, Alex, Engebretsen, Lars, Bahr, Roald, Duronio, Vincent and Khan, Karim (2007) Excessive apoptosis in patellar tendinopathy in athletes. The American Journal of Sports Medicine, 35 4: 605-611. doi:10.1177/0363546506295702

Author Lian, Øystein
Scott, Alex
Engebretsen, Lars
Bahr, Roald
Duronio, Vincent
Khan, Karim
Title Excessive apoptosis in patellar tendinopathy in athletes
Journal name The American Journal of Sports Medicine   Check publisher's open access policy
ISSN 0363-5465
Publication date 2007-04-01
Sub-type Article (original research)
DOI 10.1177/0363546506295702
Open Access Status Not yet assessed
Volume 35
Issue 4
Start page 605
End page 611
Total pages 7
Place of publication Thousand Oaks, CA, United States
Publisher Sage
Language eng
Subject 1106 Human Movement and Sports Science
Formatted abstract
The pathogenesis of tendon overuse injuries is poorly understood. The histopathology underlying tendinopathy at various anatomical locations is similar and may reflect a common pathologic process.

Apoptosis contributes to the pathophysiology in patellar tendinopathy.

Study Design:
Case control study; Level of evidence, 3.

We compared biopsy specimens from the patellar tendon in patients with patellar tendinopathy diagnosed clinically and with typical magnetic resonance image findings with biopsy specimens from a control group without any previous or current knee complaints to suggest patellar tendinopathy. The presence of apoptosis was examined with immunohistochemical methods using a polyclonal antibody recognizing active caspase-3, confirmed by labeling DNA strand breaks (F7-26 antibody) and nuclear morphology (fragmentation and condensation).

The number of apoptotic cells per unit area (4.5 mm2) was 0.91 ± 0.81 (SD) in tendinopathic samples and 0.21 ± 0.21 in controls (P = .026). Although the tendinopathic samples displayed increased cellularity (average 162.5 nuclei/mm2 vs 98.9 nuclei/mm2), the apoptotic index was higher (0.42% vs 0.17%, P = .014).


Increased apoptotic cell death is a feature of patellar tendinosis. The role of apoptosis within the broader framework and time course of tendon overuse injury remains to be established.
Keyword Tendon
Patellar tendinosis
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Official publication of the American Orthopaedic Society for Sports Medicine

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Human Movement and Nutrition Sciences Publications
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 76 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 83 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Fri, 20 Mar 2009, 20:18:48 EST by Jason Parr on behalf of School of Human Movement and Nutrition Sciences