AJSM - 2026-06-01 - Journal Article; Comparative Study
Knee Chondral Shear Injury Repair: A Biomechanical Laboratory Comparison of Suture Bridge to Chondral Pin Fixation.
Duru NO, Stoner AJ, Frey C, Pham NS, Ellis HB, Schmitz MR, Yen YM, Tompkins MA, Ganley TJ, Wilson P, Meadows MC, Chan C, Shea KG
Topics
Key Takeaway
Suture bridge fixation demonstrated significantly higher pre- and postcyclic stiffness (0.0113 vs 0.0067 N·m/deg and 0.0215 vs 0.0089 N·m/deg) compared to chondral pin fixation, with 5 of 7 chondral pin constructs failing completely by end of testing.
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Summary
This study compared suture bridge versus bioabsorbable chondral pin fixation for 15 mm circular chondral shear lesions in a pediatric cadaveric femur model. Each specimen received one repair of each type on opposing condyles, with constructs subjected to precyclic rotational shear, cyclic loading, and postcyclic rotational shear testing. Suture bridge constructs showed significantly greater stiffness at both timepoints and maintained integrity in all 7 specimens, while 5 of 7 chondral pin constructs failed completely.
Key Limitation
The extremely small sample size of 7 paired specimens limits statistical power and generalizability, and no load-to-failure data were reported, preventing determination of ultimate fixation strength.
Original Abstract
BACKGROUND
Delamination of chondral fragments in pediatric patients is common and is usually caused by osteochondritis dissecans (OCD) or patellar dislocations. For fragments with minimal to no bone, fixation with screws may not be ideal due to hardware prominence on the cartilage or suboptimal screw purchase, which can result in hardware migration and loss of fixation. Lower-profile chondral fixation devices may be ideal in these circumstances, such as the suture bridge fixation construct and bioabsorbable chondral pin fixation.
HYPOTHESIS
Suture bridge constructs would provide superior fixation over chondral pins for chondral shear injury fragments.
STUDY DESIGN
Controlled laboratory study.
METHODS
Seven pediatric cadaveric femurs were utilized. Circular lesions, 15 mm in diameter, were created on both femoral condyles. One lesion was randomized to chondral pin repair, while the other received suture bridge repair using 2-0 suture fixated with suture anchors. Each specimen was then potted before undergoing biomechanical testing on a materials testing frame. Each construct underwent precyclic rotational shear testing, cyclic loading, and postcyclic rotational shear testing. The stiffness (N·m/deg) of each repair during pre- and postcyclic rotational shear testing was recorded and compared using paired t tests.
RESULTS
Suture bridge fixations, compared with chondral pin fixations, demonstrated significantly higher precycle stiffness (0.0113 vs 0.0067 N·m/deg; P = .0359) and postcycle stiffness (0.0215 vs 0.0089 N·m/deg; P = .0421). While all suture bridge repairs remained intact, 5 of 7 chondral pin repairs fully detached by the end of biomechanical testing.
CONCLUSION
Suture bridge repair demonstrated significantly higher fixation stiffness and durability compared with chondral dart repair in the pediatric cadaveric model.
CLINICAL RELEVANCE
This study attempts to find the biomechanically superior construct for pediatric chondral shear injuries.