J Knee Surg
DOI: 10.1055/a-2741-1142
Authors
Author Affiliations
Elizabeth A. Abe
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Benjamin Miltenberg
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Michael Meghpara
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Harrison S. Fellheimer
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Elijah Hoffman
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Matthew B. Sherman
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
James J. Purtill
1
Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania,
United States
Funding Information The authors received no financial support for the research, authorship, and/or publication
of this article.
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Abstract
Patellar tendon shortening (PTS) following primary total knee arthroplasty (TKA) is
thought to occur because of excessive soft tissue tensioning during wound closure.
Few studies have examined the incidence of acute PTS in TKA patients. The purpose
of this prospective study was to evaluate the incidence and clinical implications
of acute PTS after primary TKA. All patients undergoing primary TKA for osteoarthritis
(OA) from January 2024 through April 2024 by a single, fellowship-trained surgeon
were included. Patient demographics and range of motion (ROM) were recorded preoperatively.
Range of motion and physical therapy (PT) requirements were recorded at 6-week follow-up.
Patellar tendon length was determined by the Insall-Salvati ratio (ISR) and measured
preoperatively, on postoperative day (POD) 0, and at 6 weeks following surgery. Significant
PTS was defined as a decrease in the ISR of ≥10%. In total, 89 patients were included
in the analysis. Of these, 54 (60.7%) patients experienced significant PTS and 35
(39.3%) did not experience significant PTS immediately following TKA. Preoperative
ISR and ROM was similar between cohorts; however, on POD 0, the ISR decreased by 21.9 ± 8.7%
in the significant PTS cohort versus 0.8 ± 10.9% (p < 0.001) in the insignificant PTS cohort. From POD 0 to 6 weeks postoperatively,
ISR increased by 25.0 ± 15.8% in the significant PTS cohort versus 7.6 ± 12.0% in
the insignificant PTS cohort (p < 0.001). The ISR decreased by 2.9 ± 10.9% for patients in the significant PTS cohort
and increased by 5.7 ± 7.9% for patients in the insignificant PTS cohort (p < 0.001). There was no significant difference in PT requirements or ROM between cohorts
at 6-week follow-up. Patellar tendon shortening following TKA resolved by 6 weeks
postoperatively; no ROM deficits or additional PT requirements were found to exist
between cohorts.
Keywords
patellar tendon shortening -
postoperative outcomes
Publication History
Received: 25 April 2025
Accepted: 06 November 2025
Accepted Manuscript online:
12 November 2025
Article published online:
01 December 2025
© 2025. Thieme. All rights reserved.
Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA
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