A Biomechanical Comparison of Patellar Tendon Repair Materials in a Bovine Model

Background Ruptures of the patellar tendon are rare injuries. Surgical treatment for this injury is mandatory. Hypothesis Gap formation does not differ between the three patellar tendon repair techniques. Study Design Controlled laboratory study. Methods Twelve fresh-frozen cadaveric knees were used to compare three techniques of patellar tendon repairs. The standard suture repair used two Krackow sutures placed in the avulsed patellar tendon, passed through transpatellar drill holes, and secured with the knee in 30° of flexion. In the second group, suture repair was augmented with a No. 5 Ethibond suture. In the third group, suture repair was augmented with a 2.0 Dall-Miles cable. Testing was performed with the specimens mounted to a custom knee jig with the tibia free, simulating the knee moment of a 70-kg person. Each knee was then cycled 250 times at 0.25 Hz. Results Gap formation across the standard suture repair averaged 7.3 mm; across the suture augmentation and cable augmentation groups it averaged 4.9 mm and 3.5 mm, respectively. Conclusions Augmentation of patellar tendon avulsions can decrease gap formation at the repair site, allowing early mobilization. Clinical Relevance Gap formation seen in repair without augmentation could lead to clinical failure with resultant patella alta and extensor mechanism lag.

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Mechanical Stimulation Increases Collagen Type I and Collagen Type III Gene Expression of Stem Cell–Collagen Sponge Constructs for Patellar Tendon Repair

Tissue Engineering ◽

10.1089/ten.2006.0339 ◽

2007 ◽

Vol 13 (6) ◽

pp. 1219-1226 ◽

Cited By ~ 124

Author(s):

Natalia Juncosa-Melvin ◽

Karl S. Matlin ◽

Robert W. Holdcraft ◽

Victor S. Nirmalanandhan ◽

David L. Butler

Keyword(s):

Gene Expression ◽

Stem Cell ◽

Patellar Tendon ◽

Mechanical Stimulation ◽

Collagen Type ◽

Tendon Repair ◽

Collagen Type I ◽

Collagen Sponge ◽

Type I ◽

Collagen Type Iii

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Hypoxia promotes tenocyte differentiation of mesenchymal stem cells

10.21203/rs.2.23515/v1 ◽

2020 ◽

Author(s):

Guanyin Chen ◽

wangqian zhang ◽

Jintao Gu ◽

Yuan Gao ◽

Lei He ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Patellar Tendon ◽

Tendon Repair ◽

Clinical Results ◽

Tendon Injury ◽

Tenogenic Differentiation ◽

Tgf Β1

Abstract Background: Tendon injury is a common but tough medical problem. Unsatisfactory clinical results have been reported in tendon repair using mesenchymal stem cells (MSCs) therapy, creating a need for a better strategy to induce MSCs to tenogenic differentiation. This study was designed to investigate the role of hypoxia in the tenogenic differentiation of MSCs in vitro and in vivo and to compare the tenogenic differentiation capacities of different MSCs under hypoxia condition in vitro. Methods: Adipose tissue-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) were isolated and characterized by the expression of MSC-specific markers and tri-lineage differentiation. The expression of hypoxia induced factor-1 alpha (Hif-1α) and the proliferation of AMSCs and BMSCs were examined in order to confirm the establishment of hypoxia condition. qRT-PCR, western blot, and immunofluorescence staining were used to evaluate the expression of tendon-associated marker Col-1a1, Col-3a1, Dcn, and Tnmd in AMSCs and BMSCs under hypoxia and/or Tgf-β1 condition. In vivo, a patellar tendon injury model was established. Normoxic and hypoxic BMSCs were cultured and implanted. Histological, biomechanical and transmission electron microscopy analyses were performed to assess the improved healing effect of hypoxic BMSCs on tendon injury. Results: Hypoxia remarkably increased the expression of Hif-1α and the proliferation of AMSCs and BMSCs. Our in vitro results detected that hypoxia not only promoted a significant increase in tenogenic markers in both AMSCs and BMSCs compared with the normoxia group, but also showed higher inductility compared with Tgf-β1. In addition, hypoxic BMSCs exhibited higher potential of tenogenic differentiation than hypoxic AMSCs. Our in vivo results demonstrated that hypoxic BMSCs possessed better histological and biomechanical properties than those of normoxic BMSCs, as evidenced by histological scores, quantitative analysis of immunohistochemical staining for Col-1a1 and Tnmd, the range and average of collagen fibril diameters and patellar tendon biomechanical tests. Conclusions: These findings suggested that hypoxia may be a practical and reliable strategy to induce tenogenic differentiation of BMSCs for tendon repair and could enhance the effectiveness of MSCs therapy in treating tendon injury.

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Hypoxia-Induced Mesenchymal Stem Cells Exhibit Stronger Tenogenic Differentiation Capacities and Promote Patellar Tendon Repair in Rabbits

Stem Cells International ◽

10.1155/2020/8822609 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Guanyin Chen ◽

Wangqian Zhang ◽

Kuo Zhang ◽

Shuning Wang ◽

Yuan Gao ◽

...

Keyword(s):

Patellar Tendon ◽

Tendon Repair ◽

Biomechanical Properties ◽

Clinical Results ◽

Medical Problem ◽

Tendon Injury ◽

Tenogenic Differentiation ◽

Tgf Β1

Tendon injury is a common but tough medical problem. Unsatisfactory clinical results have been reported in tendon repair using mesenchymal stem cell (MSC) therapy, creating a need for a better strategy to induce MSCs to tenogenic differentiation. This study was designed to examine the effect of hypoxia on the tenogenic differentiation of different MSCs and their tenogenic differentiation capacities under hypoxia condition in vitro and to investigate the in vivo inductility of hypoxia in tenogenesis. Adipose tissue-derived MSCs (AMSCs) and bone marrow-derived MSCs (BMSCs) were isolated and characterized. The expression of hypoxia-induced factor-1 alpha (Hif-1α) was examined to confirm the establishment of hypoxia condition. qRT-PCR, western blot, and immunofluorescence staining were used to evaluate the expression of tendon-associated marker Col-1a1, Col-3a1, Dcn, and Tnmd in AMSCs and BMSCs under hypoxia condition, compared with Tgf-β1 induction. In vivo, a patellar tendon injury model was established. Normoxic and hypoxic BMSCs were cultured and implanted. Histological, biomechanical, and transmission electron microscopy analyses were performed to assess the improved healing effect of hypoxic BMSCs on tendon injury. Our in vitro results showed that hypoxia remarkably increased the expression of Hif-1α and that hypoxia not only promoted a significant increase in tenogenic markers in both AMSCs and BMSCs compared with the normoxia group but also showed higher inductility compared with Tgf-β1. In addition, hypoxic BMSCs exhibited higher potential of tenogenic differentiation than hypoxic AMSCs. Our in vivo results demonstrated that hypoxic BMSCs possessed better histological and biomechanical properties than normoxic BMSCs, as evidenced by histological scores, patellar tendon biomechanical parameters, and the range and average of collagen fibril diameters. These findings suggested that hypoxia may be a practical and reliable strategy to induce tenogenic differentiation of BMSCs for tendon repair and could enhance the effectiveness of MSCs therapy in treating tendon injury.

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