Patellar Tendon Autografts Outperform Fascia Lata in Superior Capsular Reconstruction: A Comparative Histopathological and Biomechanical Study

Muhammed Uslu; Erdinc Genc; Ergun Bozdag; Fatih Yamak; Mehmet Kapicioglu; Serdar Yuksel; Kerem Bilsel

doi:10.1016/j.jse.2025.05.015

Patellar Tendon Autografts Outperform Fascia Lata in Superior Capsular Reconstruction: A Comparative Histopathological and Biomechanical Study

J Shoulder Elbow Surg. 2025 Jun 26:S1058-2746(25)00484-7. doi: 10.1016/j.jse.2025.05.015. Online ahead of print.

Authors

Muhammed Uslu¹, Erdinc Genc², Ergun Bozdag³, Fatih Yamak³, Mehmet Kapicioglu⁴, Serdar Yuksel⁵, Kerem Bilsel⁶

Affiliations

¹ Department of Orthopedics and Traumatology, University of Health Science, Bagcilar Training and Research Hospital, Istanbul, Turkey.
² Department of Orthopedics and Traumatology, Istanbul Medipol University, Bahçelievler Medipol Hospital, Istanbul, Turkey. Electronic address: erdincgenc@yahoo.com.
³ Department of Mechanical Engineering, Istanbul Technical University, Istanbul, Turkey.
⁴ Department of Orthopedics and Traumatology, T.C. Bezmialem Vakif University, Istanbul, Turkey.
⁵ Department of Orthopedics and Traumatology, Istanbul Physical Therapy and Rehabilitation Training and Research Hospital, Istanbul, Turkey.
⁶ Department of Orthopaedics and Traumatology, Fulya Acibadem Hospital, Istanbul, Turkey.

PMID: 40581085
DOI: 10.1016/j.jse.2025.05.015

Abstract

Background: In the treatment of irreversible rotator cuff (RC) tears, surgeons reconstruct the superior capsule of the shoulder using tensor fascia lata (TFL) or various allografts to halt progressive joint degeneration. This study evaluated the healing characteristics of patellar tendon (PT) autograft versus TFL autograft in superior capsule reconstruction (SCR), examining both biomechanical and histological aspects.

Methods: A total of 28 shoulders from 14 rabbits were used in this experimental study. Retracted tear models involving complete resection of both the supraspinatus and subscapularis tendons were created in all surgical groups. After an 8-week retraction period, superior capsular reconstruction (SCR) was performed using standardized techniques: fascia lata (FL) autografts were implanted in the right shoulders and patellar tendon (PT) autografts in the left shoulders, while the control group received no intervention. All grafts were fixed identically with bone tunnels and prolene sutures at the glenoid superiorly and the greater tuberosity laterally. Rabbits were observed for 8 weeks postoperatively. Outcome measures included biomechanical testing (load-to-failure) and histopathological analysis (tendon maturation scoring, collagen type I-III ratio, and CD31 immunoreactivity).

Results: Post hoc pairwise analysis revealed that the load-to-failure values were significantly lower in FL group compared to control group (P<0.01), suggesting that FL group could not maintain biomechanical stability and tendon-bone integration. No significant difference was found between PT and control groups(P>0.05). Cellularity, vascularity, collagen continuity, and tidemark development showed no significant differences between the PT and control groups (P>0.05), while these parameters were significantly reduced in the FL group (P<0.05). FL group's mean total modified Watkins score was much lower than that of the control group (P=0.01) whilst the PT group nearly equaled the control group. Tendons of PT groups had significantly higher immunoreactivity for collagen type I and type III and CD31 compared to the control group (P=0.019, P=0.015 and P=0.014, respectively).

Conclusions: In this rabbit model, PT autografts showed superior biomechanical strength, vascularity, and collagen remodeling compared to FL autografts in SCR, suggesting improved graft integration. Further studies, including cadaver-based research and clinical trials, are required to validate these findings and establish the clinical relevance of graft choice for SC in humans.

Keywords: Superior capsular reconstruction; fascia lata; irreparable cuff tears; patellar tendon.