Persistent underloading of patellofemoral joint following hamstring autograft ACL reconstruction is associated with cartilage health

Tzu Chieh Liao, Alyssa Bird, Michael A. Samaan, Valentina Pedoia, Sharmila Majumdar, Richard B. Souza

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Objective: To determine the longitudinal changes of patellofemoral joint (PFJ) contact pressure following anterior cruciate ligament reconstruction (ACLR). To identify the associations between PFJ contact pressure and cartilage health. Design: Forty-nine subjects with hamstring autograft ACLR (27 males; age 28.8 [standard deviation, 8.3] years) and 19 controls (12 males; 30.7 [4.6] years) participated. A sagittal plane musculoskeletal model was used to estimate PFJ contact pressure. A combined T/T2 magnetic resonance sequence was obtained. Assessments were performed preoperatively, at 6 months, 1, 2, and 3 years postoperatively in ACLR subjects and once for controls. Repeated Analysis of Variance (ANOVA) was used to compare peak PFJ contact pressure between ACLR and contralateral knees, and t-tests to compare with control knees. Statistical parametric mapping was used to evaluate the associations between PFJ contact pressure and cartilage relaxation concurrently and longitudinally. Results: No changes in peak PFJ contact pressure were found within ACLR knees over 3 years (preoperative to 3 years, 0.36 [CI, −0.08, 0.81] MPa), but decreased over time in the contralateral knees (0.75 [0.32, 1.18] MPa). When compared to the controls, ACLR knees exhibited lower PFJ contact pressure at all time points (at baseline, −0.64 [−1.25, −0.03] MPa). Within ACLR knees, lower PFJ contact pressure at 6 months was associated with elevated T2 times (r = −0.47 to −0.49, p = 0.021–0.025). Conclusions: Underloading of the PFJ following ACLR persists for up to 3 years and has concurrent and future consequences in cartilage health. The non-surgical knees exhibited normal contact pressure initially but decreased over time achieving limb symmetry.

Original languageEnglish
Pages (from-to)1265-1273
Number of pages9
JournalOsteoarthritis and Cartilage
Issue number9
StatePublished - Sep 2023

Bibliographical note

Funding Information:
TCL, RBS, and VP provided the conception and design of the manuscript as well as the interpretation of the data. TCL, AB, and MAS performed the analysis and assembly of data. The drafting of the article was mainly done by TCL. All authors contributed to the critical revision and final approval of the article. Fundings were from NIH-NIAMS (P50 AR060752, K24 AR072133, R00 AR070902, R61 AR073553) and NIH (K01 AG073698). There are no conflicts of interest to disclose. The authors thank Dr. Xiaojuan Li and Dr. Benjamin C. Ma for their contributions to the design and execution of this project and Jonathan Groening for his assistance in data processing.

Publisher Copyright:
© 2023 Osteoarthritis Research Society International


  • Anterior cruciate ligament reconstruction
  • Cartilage relaxation times
  • Contact pressure
  • Hamstring autograft
  • Osteoarthritis

ASJC Scopus subject areas

  • Rheumatology
  • Biomedical Engineering
  • Orthopedics and Sports Medicine


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